WO2000029667A1 - Method for maximizing water removal in a press nip - Google Patents

Method for maximizing water removal in a press nip Download PDF

Info

Publication number
WO2000029667A1
WO2000029667A1 PCT/US1999/027097 US9927097W WO0029667A1 WO 2000029667 A1 WO2000029667 A1 WO 2000029667A1 US 9927097 W US9927097 W US 9927097W WO 0029667 A1 WO0029667 A1 WO 0029667A1
Authority
WO
WIPO (PCT)
Prior art keywords
nip
pressing unit
web
pressure
less
Prior art date
Application number
PCT/US1999/027097
Other languages
French (fr)
Other versions
WO2000029667A9 (en
Inventor
Robert J. Marinack
Jeffrey Charles Mcdowell
Gary L. Worry
Steven L. Edwards
Original Assignee
Fort James Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fort James Corporation filed Critical Fort James Corporation
Priority to EP99960375A priority Critical patent/EP1047830A1/en
Priority to CA002317438A priority patent/CA2317438C/en
Publication of WO2000029667A1 publication Critical patent/WO2000029667A1/en
Publication of WO2000029667A9 publication Critical patent/WO2000029667A9/en
Priority to US10/376,319 priority patent/US7300552B2/en
Priority to US11/874,251 priority patent/US7754049B2/en

Links

Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00Press section of machines for making continuous webs of paper
    • D21F3/02Wet presses
    • D21F3/0209Wet presses with extended press nip
    • D21F3/0218Shoe presses
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F11/00Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
    • D21F11/14Making cellulose wadding, filter or blotting paper
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F11/00Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
    • D21F11/14Making cellulose wadding, filter or blotting paper
    • D21F11/145Making cellulose wadding, filter or blotting paper including a through-drying process
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00Press section of machines for making continuous webs of paper
    • D21F3/02Wet presses
    • D21F3/0209Wet presses with extended press nip
    • D21F3/0218Shoe presses
    • D21F3/0227Belts or sleeves therefor
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00Press section of machines for making continuous webs of paper
    • D21F3/02Wet presses
    • D21F3/0281Wet presses in combination with a dryer roll
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F3/00Press section of machines for making continuous webs of paper
    • D21F3/02Wet presses
    • D21F3/029Wet presses using special water-receiving belts
    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H25/00After-treatment of paper not provided for in groups D21H17/00 - D21H23/00
    • D21H25/08Rearranging applied substances, e.g. metering, smoothing; Removing excess material
    • D21H25/12Rearranging applied substances, e.g. metering, smoothing; Removing excess material with an essentially cylindrical body, e.g. roll or rod
    • D21H25/14Rearranging applied substances, e.g. metering, smoothing; Removing excess material with an essentially cylindrical body, e.g. roll or rod the body being a casting drum, a heated roll or a calender

Definitions

  • the invention relates to a method for maximizing water removal from an absorbent paper web in a press nip. More particularly, the present invention relates to the use of a shoe press on the Yankee dryer with a pressure profile that maximizes water removal. Still more particularly, the present invention relates to a method for utilizing a very steep pressure drop at and/or following the exit of a nip curve in order to maximize water removal by minimizing rewet. Finally, the present invention relates to a method for increasing paper machine speed by utilizing a press section that maximizes water removal.
  • packaged paper products In modern society, bath tissue, paper towels, facial tissue, and paper napkins (hereinafter referred to as packaged paper products) have been remarkably successfully consumer products. The success of these paper products stems from the ability of manufacturers to consistently enhance product attributes at lower cost and to meet volume demands on a timely basis.
  • Packaged paper products offer consumers an array of attributes necessary to such jobs as performing the daily tasks of wiping up spills, personal cleansing, and cleaning household goods.
  • paper towels are engineered to be absorbent and strong while wet whereas bath tissue products are expected to be soft to the touch yet strong while in use. Absorbency and softness are inversely related to strength, often making it difficult to obtain the right balance of attributes.
  • This patent describes a papermaking scheme for enhancing product quality by avoiding overall web compression and by using a pattern array of densified regions in the xy plane of the sheet to enhance product strength.
  • Thicker more absorbent structures can be made using a low batting papermaking felt as described in U.S. Patent No. 4,533,457 by Curran et al., assigned to Scott Paper Company, and incorporated herein by reference in its entirety.
  • a more recent method for improving the quality of a through-air-dried sheet is described in U.S. Patent No. 4,440,597 by Wells and Hensler, assigned to Procter and Gamble Company, and incorporated herein by reference in its entirety.
  • This patent describes a method for increasing the stretch of a paper web by operating the forming section of a paper machine faster than the through air dryer section of the paper machine. As a result of the speed differential, the paper web is inundated into the through air-dryer- fabric leading to enhanced stretch and absorbency properties in the base sheet and resulting product.
  • Fibers and chemicals can be used to enhance the quality of packaged paper products.
  • U.S. Patent No. 5,320,710 by Reeves et al., assigned to Fort James Corporation, and incorporated herein by reference in its entirety describes a new furnish combination extracted from the species Funifera of the genus Hesporaloe in the Agavaceae family. This furnish has fibers which are very long and which have very fine-geometrical attributes known to enhance tissue and towei performance.
  • U.S. Patent No. 3,755,220 by Freimark and Schaftlein, assigned to Scott Paper Company, and incorporated herein by reference in its entirety describes a debonding scheme for maintaining wet strength while reducing product dry strength-a method known to enhance the handfeel of towel products.
  • U.S. Patent No. 5,348,620 by Hermans et al., assigned to Kimberly- Clark Worldwide Inc., and incorporated herein by reference discusses a high consistency/high temperature fiber-treatment-process using a disperser to improve product attributes.
  • a disperser to improve product attributes.
  • several approaches are available to the papermaker such as using certain species of hardwood like eucalyptus in stratified webs as disclosed in U.S. Patent No. 4,300,981 by Carstens and U.S. Patent No. 3,994,771 by Morgan et al.
  • the last two patents are incorporated herein by reference in their entirety. These aforementioned patents describe just a few of the many methods developed over the last thirty years to enhance the quality of packaged paper products.
  • gap formers have been developed to enhance sheet drainage ultimately leading to increased machine speed.
  • New developments in Yankee hood design and Yankee cylinder design have allowed improvements in heat transfer coefficients and mass transfer coefficients, ultimately leading to enhanced machine speeds.
  • New developments in forming fabrics, e.g., multi-layer and triple-layer forming fabrics have resulted in improved drainage, better fabric life, and enhanced fiber support. These factors translate into enhanced machine speed and productivity. Improvements in press felts, e.g.
  • the present invention improves the efficiency of known water removal methods by adding one or more pressing units to the production paper machine, in place of or in conjunction with a suction pressure roll.
  • Pressure units include those units that physically engage a belt or pressing blanket, which contacts the impression fabric or felt upon which the web travels.
  • Formaminous endless fabric as defined in accordance with the present invention includes either an impression fabric or felt.
  • Pressing unit as defined in accordance with the present invention includes any press members allowing deformation of the pressing blanket/impression fabric and/or felt/web sandwich to result in asymmetric pressure profiles.
  • Pressing units including pressing blankets are generally discussed in the literature as “shoe presses.”
  • Pressing units according to the present invention do not include suction pressure rolls since they lead to symmetrical pressure distributions frequently mathematically described by sine or haversine functions.
  • Shoe presses have been used to increase water removal at wet presses, ultimately leading to increased machine speed for linerboard grades and more recently, newsprint and fine paper grades.
  • the idea of extending the time in a press nip as a means to enhance water removal is not a new idea.
  • Nissan in 1954 published a paper in Tappi, Vol. 37, No.12, p.597 (1954) suggesting that the use of extended time in a press nip would enhance the water removal performance of a press.
  • a wide shoe press as described in the literature is essentially a controlled crown roll with a flexible shell and a concave shoe hydrodynamically loaded against each other.
  • the belt or blanket is usually a fabric reinforced polyurethane-coated structure that can be grooved or blind drilled for more efficient water removal.
  • the inside of the belt is generally lubricated with oil, which develops a hydrodynamic film as it passes over the shoe and reduces wear/friction in both surfaces.
  • Wide shoe press nips are on average 5 to 10 times longer than conventional roll press nips (generally, 5" - 10" versus 1" - 2"). Water deflectors (not shown) on the outside surface will dewater the blanket.
  • Yankee dryers are loaded with suction pressure rolls to remove water from the tissue web and attach the web to the dryer for further processing by the creping operation.
  • the pressure distribution in the suction pressure roll nip is symmetrical in shape and is described mathematically by a sine or a haversine curve.
  • Suction pressure rolls loaded to a Yankee dryer are
  • the loading cylinders are located at each end of the pressure roll, profiling
  • the typical peak pressure is on the order of 1700 kN/m as Figure 3 demonstrates. Since the press nip for low weight tissue and towel grades is pressure controlled, the very low peak pressure could cause a decrease in
  • Ampulski et al. achieves this extended nip length through the use of a shoe press. Ampulski et al., like all previous users of shoe presses, fails to consider the use of increased peak pressure.
  • dwell times in an extended nip press serve to density the sheet beyond that experienced by conventional tissue wet pressing methods.
  • Friedbaurer overcome the increased density due to extended nip pressing by incorporating modified resilient fibers (e.g., chemically cross-linked cellulosic fibers) in the web and by wet micro-shaping the web. They also disclose shoe lengths typically in the range of 5 to 10 inches. Like Ampulski et al., Hermans and Friedbaurer do not consider critical peak pressures or line loads
  • the '384 patent describes the use of a shoe press preceding or contacting a Yankee drying cylinder.
  • the shoe press is used in conjunction with an impermeable belt to reduce remoistening of the sheet by the felt.
  • presses are suited essentially for drying thick, heavy webs, since they
  • the second nip is a shoe press nip.
  • the criticality of pressure distribution shape and peak pressure/line load magnitudes are not disclosed in the '092 patent. In the September 1997 article W. Schuwerk, "Shoe Presses and
  • Steiner et al. also discloses that the joint path of travel of the paper web, felt, and blanket can be made substantially shorter than prior art.
  • the joint travel of the felt, web, and blanket can be made equal to zero, i.e., the web can detach itself from the felt directly at the emergence from the press nip.
  • Steiner et al. does not address low line loads and high peak pressures needed for optimum shoe press
  • Escher Wyss and incorporated herein by reference describes a process for
  • the heated pressing arrangement can be a shoe press.
  • Crouse et al. found that by application of pressure for an increased period of time, the
  • WO 97/16593 by Wedel and Worcester discloses an impulse drying method for tissue structures using a
  • the present inventors unexpectedly discovered that good sheet dewatering and appropriate bulk/strength properties for low weight absorbent products could be attained with this pressure optimized shoe press.
  • the optimized pressure conditions can be achieved according to the present
  • the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m 2 at an overall line load of less than about 240 kN/m.
  • An apparatus for forming an absorbent paper sheet product comprising: a moving foraminous endless fabric;
  • a pressing unit engaging the pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric into engagement with the Yankee drying cylinder thereby forming a nip
  • the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m 2 at an overall line load of less than about 240 kN/m, the pressing unit being configured to disengage the web from the foraminous endless fabric such that rewet of the nascent web by the foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the properties of the foraminous endless
  • a pressing unit engaging the pressing blanket adapted to urge the
  • pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m 2 at an overall line load of less than about 240 kN/m,
  • the pressing unit being configured to both disengage the web from the foraminous endless fabric and disengage the foraminous endless fabric from the pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches zero.
  • a pressing unit engaging the pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric into engagement with the transfer cylinder thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m 2 at an overall line load of less than about 240 kN/m.
  • a moving endless pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric into engagement with the transfer cylinder thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about
  • a nascent web for the absorbent paper sheet on the foraminous endless fabric means for depositing a nascent web for the absorbent paper sheet on the foraminous endless fabric; a moving endless pressing blanket; a backing roll; and a pressing unit engaging the pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric
  • the pressing unit being configured to create a peak engagement pressure of at least about
  • a method of making an absorbent paper sheet product comprising:
  • the moving foraminous endless fabric and contacting the moving foraminous endless fabric bearing the deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m 2 at an overall line load of
  • a method of making an absorbent paper sheet product comprising:
  • a method of making an absorbent paper sheet product comprising:
  • nascent web with a shoe press thereby forming a nip between the shoe press and a Yankee drying cylinder, the shoe press being configured to create a peak engagement pressure of at least about 2000 kN/m 2 at an overall line load of less than about 240 kN/m; disengaging the web from the foraminous endless fabric in the nip onto
  • Figure 1 illustrates a side view of a typical stand alone shoe press.
  • Figure 2 illustrates the relationship between peak pressure and line load for a variety of shoe press arrangements found in the literature, as well as for Yankee suction pressure rolls.
  • Figure 3 illustrates nip pressure profiles for a suction pressure roll
  • FIG 4 illustrates one conventional wet press processing apparatus.
  • FIG. 5 illustrates one conventional through-air-drying processing
  • Figure 6 illustrates a typical pressure profile in the nip of a suction
  • Figure 7 illustrates a pressure profile in the nip of a shoe press.
  • Figure 8 illustrates a preferred pressure profile in the nip of a shoe press where the negative pressure corresponds to the vacuum level in the
  • Figure 9 illustrates a shoe press with a large diameter transfer cylinder
  • Figure 10 illustrates a tapered shoe in a shoe press with a large diameter transfer cylinder where the felt is rapidly separated from the web but
  • Figure 11 illustrates a tapered shoe in a shoe press with a large diameter transfer cylinder where the felt is simultaneously stripped from the sheet and from the pressing blanket on the exit side of the nip.
  • Figure 12 shows a plot of cold Yankee press solids versus line loading for a conventional 120 mm shoe, for a 50 mm shoe made according to the present invention, and for a suction pressure roll.
  • Figure 13 illustrates a side view of a typical stand alone shoe press
  • Figure 14 illustrates a blind drilled blanket or belt.
  • Figure 15 illustrates a grooved blanket or belt.
  • the present invention improves paper web moisture removal through the controlled use of a pressing unit in conjunction with a backing roll and/or a transfer cylinder or Yankee drying cylinder.
  • An absorbent paper web as defined herein includes bath tissue, paper towels, paper napkins, wipers, and facial tissue. The basis weight of such products and their base sheets
  • absorbent paper may be produced
  • papermaking methods are (I) conventional wet pressing (CWP) and (II)
  • TAD through-air-drying
  • a furnish is fed by means not shown through conduits (40, 41 ) to headbox chambers (20, 20').
  • a web (W) is formed on a conventional wire former on fabric (12), supported by rolls (18, 19), from a
  • conduit (24) The web is then transferred to a moving felt (14), supported by roll (11 ) for pressing and drying. Materials removed from
  • Liquid adhesive may be applied to the surface of the
  • web is then usually passed between calender rollers (not shown) and rolled up on reel (28) prior to further converting operations, for example, embossing.
  • a web may alternatively be subjected to vacuum deformation on an
  • impression fabric alone or in conjunction with other physical deformation
  • TAD process through- air-drying process
  • the web is carried along forming fabric (30) until it is transferred to a TAD fabric (70) at junction (80) by means of a vacuum pickup shoe (90).
  • the web is further dewatered at dewatering box (100) to increase web solids. Besides removing water from the web, vacuum pickup shoe (90) and
  • dewatering box (100) inundate the web into TAD fabric (70) causing bulk and absorbency improvements.
  • the web is then carried on TAD fabric (70) to drying unit (110) where heated air is passed through both the web and the fabric to increase the solids content of the web.
  • drying unit (110) where heated air is passed through both the web and the fabric to increase the solids content of the web.
  • the web is 30 to 95% dry after exiting drying unit (110).
  • the web may be removed directly from TAD fabric (70) in an uncreped state.
  • creped web is then usually passed between calender rollers (160) and rolled
  • an absorbent paper web can be made by dispersing fibers into aqueous slurry and depositing the aqueous
  • any art recognized forming scheme might be used.
  • an extensive but non- exhaustive list includes a crescent former, a C-wrap twin wire former, an S- wrap twin wire former, a suction breast roll former, a fourdrinier former, or any
  • the forming fabric can be any material that is critical to the success of the present invention.
  • the forming fabric can be any material that is not critical to the success of the present invention.
  • the forming fabric can be any material that is not critical to the success of the present invention.
  • One forming fabric found particularly
  • present invention include cellulosic fibers commonly referred to as wood pulp
  • Fibers liberated in the pulping process from softwood (gymnosperms or coniferous trees) and hardwoods (angiosperms or deciduous trees).
  • Cellulosic fibers from diverse material origins may be used to form the web of
  • These fibers include non-woody fibers liberated from
  • sugar cane bagasse, sabai grass, rice straw, banana leaves, paper mulberry (i.e., bast fiber), abaca leaves, pineapple leaves, esparto grass leaves, and fibers from the genus Hesperaloe in the family Agavaceae. Also recycled
  • Suitable fibers are
  • Papermaking fibers can be liberated from their source material by any one of the number of chemical pulping processes familiar to one experienced in the art including sulfate, sulfite, polysulfide, soda pulping, etc.
  • the pulp can be bleached if desired by chemical means including the use of chlorine,
  • papermaking fibers can be liberated from source material by any one of a number of
  • thermomechanical pulping These mechanical pulps can be bleached, if
  • the suspension of fibers or furnish may contain chemical additives to alter the physical properties of the paper produced. These chemistries are well understood by the skilled artisan and may be used in any known
  • the pulp can be mixed with strength adjusting agents such as wet
  • urea-formaldehyde resins melamine formaldehyde resins, glyoxylated polyacrylamide resins, polyamide-epichlorhydrin resins and the like.
  • Thermosetting polyacrylamides are produced by reacting acrylamide with
  • DMAC diallyl dimethyl ammonium chloride
  • dialdehydes can be substituted for glyoxal to produce thermosetting wet
  • polyamide-epichlorhydrin resins an example of which is sold under the tradenames Kymene 557LX and Kymene 557H by Hercules Incorporated of Wilmington, Delaware and CASCAMID® from Borden Chemical Inc. These resins and the process for
  • the pulp when making towel grades according to the present invention, preferably contains up to about 30 lbs/ton, more preferably from 10 to 20 lbs/ton of wet strength aids. Wet strength resins are not normally added
  • carboxymethyl cellulose includes starch, guar gum, polyacrylamides, carboxymethyl cellulose and the like. Of particular utility is carboxymethyl cellulose, an example of which is
  • the pulp preferably contains from 0 to10 lbs/ton, more preferably from 1 to 5 lbs/ton of dry strength aid.
  • debonders will be readily apparent to the skilled artisan. Debonders or softeners may also be incorporated into the pulp or sprayed
  • the pulp preferably contains from 0 to 10 lbs/ton, more preferably from 1 to 5 lbs/ton of debonder/softener.
  • the present invention may be used with a particular class of softener materials - amido amine salts derived from partially acid neutralized amines.
  • Quasoft 202-JR is a suitable softener material, which may be derived by alkylating a condensation product of oleic acid and diethylenetriamine.
  • non-ethylated species result in a mixture consisting of cationic ethyiated and cationic non-ethylated species.
  • a minor proportion (e.g., about 10%) of the resulting amido amine cyclize to imidazoline compounds. Since only the imidazoline portions of these material are quaternary ammonium compounds,
  • compositions as a whole are pH-sensitive. Therefore, in the practice of the present invention with this class of chemicals, the pH in the headbox
  • Quaternary ammonium compounds such as dialkyl dimethyl quaternary ammonium salts are also suitable particularly when the alkyl
  • Biodegradable softeners can be utilized. Representative biodegradable cationic softeners/debonders are disclosed in U.S. Patent Nos.
  • the fibrous web is then either deposited on an impression drying
  • impression fabrics would include plain weave fabrics described in U.S. Patent No. 3,301 ,746; semitwill fabrics described in U.S. Patent Nos. 3,974,025 and 3,905,863; bilateraily- staggered-wicker-basket-cavity type fabrics described in U.S. Patent Nos.
  • felts can have double- layer base weaves, triple-layer base weaves, or laminated base weaves.
  • Preferred felts according to the present invention are those having the laminated base weave design.
  • a wet-press-felt found particularly useful with the present invention is AMFIex 3 made by Appleton Mills Corporation.
  • Non- exhaustive background art in the press felt area includes U.S. Patent Nos. 5,657,797; 5,368,696; 4,973,512; 5,023,132; 5,225,269; 5,182,164;
  • web/foraminous fabric sandwich is contacted with a pressing blanket engaged with a pressing unit, one embodiment in the art referred to as a shoe press.
  • the web/foraminous fabric sandwich is preferably contacted with the pressing blanket engaged with a pressing unit after the web has reached a solids content of at least about
  • the pressing unit including a pressing blanket according to the present invention can have any art-recognized configuration.
  • the nip can be created
  • backing roil refers to a roll that contacts the web but does not remove the fibrous web from the carrier fabric or felt.
  • Backing rolls for use according to the present invention may be
  • the backing roll can be made of hard rubber or metal.
  • the rolls are heated with an induction heater
  • the roll is preferably constructed or coated with high diffusivity material, such as copper, to aid in increasing
  • transfer cylinder refers to a roll that
  • cylinders according to the present invention can include a steel roll, a metal coated roll, a granite roll, a Yankee drying cylinder, and a gas fired drying cylinder.
  • Transfer cylinders for use according to the present method may be heated or cold.
  • the transfer cylinder is heated with an induction heater the cylinder is preferably constructed or coated with high diffusivity material, such as copper, to aid in increasing heat transfer.
  • high diffusivity material such as copper
  • Heat is preferably applied to the transfer cylinder and/or backing roll.
  • Heat can be applied by any art-known scheme including induction heating, oil heating and steam heating. Commercial available induction heaters can be used to heat any art-known scheme including induction heating, oil heating and steam heating. Commercial available induction heaters can be used to heat any art-known scheme. Commercial available induction heaters can be used to heat any art-known scheme. Commercial available induction heaters can be used to heat any art-known scheme. Commercial available induction heaters can be used to heat any art-known scheme including induction heating, oil heating and steam heating. Commercial available induction heaters can be used to any art-known scheme. Commercial available induction heaters can be used to heat.
  • Backing roll or transfer cylinder temperature can be anywhere from ambient to 700 ° F but are more preferably from 180 ° F to
  • Preferred heating schemes according to the present invention are induction heating and steam-heating. Increased temperature in the backing roll or transfer cylinder
  • the pressing unit including a pressing blanket according to the
  • a shoe press includes a shoe element(s), which is pressed against the backing roll or transfer cylinder.
  • the shoe element is loaded hydrodynamically against the backing roll or transfer
  • a pressing belt or blanket traverses the shoe press nip with the fibrous web in contact with the foraminous fabric. Pressing blankets can be smooth, or to enhance water removal at the press they can be grooved or blind drilled. Conventional pressing blanket designs contain a fabric coated with polyurethane where the fabric is used as reinforcement. Other pressing blanket designs use yarns embedded in the polyurethane to provide reinforcement.
  • One preferred pressing blanket according to the present invention is a yarn reinforced blanket design under the tradename QualiFlex B, which is supplied by Voith Sulzer Corporation.
  • the shoe element length can be less than about 7 inches but is more preferably less than about 3 inches for the present invention. According to the present invention the shoe element will also be referred to as a hydraulic
  • Shoe designs can be hydrodynamic, hydrodynamic
  • the hydrodynamic pocket design incorporates a machined full width pocket in the shoe used for emptying the oil in the pressurized zone of the shoe.
  • the final design is the hydrostatic design where oil is fed into the center region of the shoe.
  • the preferred shoe design according to the present invention is hydrodynamic.
  • Shoe presses for use according to the present invention can be open
  • the peak pressure in the shoe press is preferably greater than about 2000 kN/m 2 , with a line load of preferably less than about 240 kN/m.
  • the peak pressure is preferably greater than about 2000 kN/m 2 , while the line load is
  • kN/m is an abbreviation for
  • kilonewtons per meter and kN/m 2 is an abbreviation for kilonewtons per
  • the sheet can be creped from the transfer cylinder by any art- recognized methods using any art recognized creping aid.
  • the maximum line load a current standard Yankee can sustain is on the order of 100kN/m.
  • the Yankee needs to be precisely crowned at the prevailing load to obtain a uniform nip. This procedure is necessary due to the inflexibility of
  • Figure 6 shows a schematic sketch of a typical pressure distribution curve for a suction pressure roll described by symmetrical mathematical functions like the sine and haversine curves. Since the nip pressure is
  • Figure 7 shows a schematic sketch of a pressure distribution curve for a shoe press with a steep drop off where the felt is stripped from the sheet and
  • Figure 8 shows a schematic sketch of a pressure distribution curve for a shoe press with a steeper drop off and where suction occurs in the felt at the point of simultaneous separation of the felt, sheet, and blanket when the nip pressure reaches about zero.
  • the negative pressure in the felt, when the blanket and felt are stripped apart, is caused by capillary forces and should aid in holding water in the felt and should help further
  • Figure 9 is a schematic sketch of a shoe press nip showing sheet, felt, and blanket. Point A in Figure 9 is the point of zero pressure on
  • K p K 0 + R/W
  • K p is the moisture ratio of the paper after the wet press in grams
  • R is the magnitude of the rewet of paper in g/m 2 and corresponds to the slope of the straight line used to fit moisture ratio versus
  • Sweet plot frequently referred to in the literature as a Sweet plot.
  • the original work can be found in Sweet, J.S., Pulp and Paper Mag. Can., 62, No. 7: T267 (1961 ) and a review article can be found in Heller, H., MacGregor, M., and Bliesner,
  • Rewet has been estimated to be from 5 to 50 g/m 2 of water, depending on the
  • Rewet for a conventional shoe press can be determined from the above equation.
  • the amount of rewet for the optimum shoe press is preferably less than about 50 % of the amount determined from Sweet's
  • Rewet is preferably from 0 to
  • a pressing felt wraps the blanket and, therefore, pulls away quickly from the sheet reducing the time for possible rewetting.
  • This design can be achieved by altering the take-away angle of the felt from the nip and tapering the exit side of the shoe.
  • the blanket diameter can be reduced; the blanket can be eccentrically arranged with respects to the press plane; or a roll (not shown in Figure 10) positioned against the blanket can deflect the belt
  • FIG. 11 shows another embodiment according to the present
  • FIG 11 a schematic sketch of a shoe press showing a sheet, felt, and blanket is displayed. This shoe press utilizes a very steep pressure
  • the press can control the tension level on the felt.
  • the objective of this embodiment according to the present invention is to affect the transfer of the sheet from the felt at the same time that the negative pulse caused by the separation of the felt and blanket occurs. This design not only minimizes the
  • Point A in Figure 11 is the point of zero pressure on the pressure
  • the web is preferably either adhered to the Yankee dryer by nip
  • the web is dried by steam and hot air
  • any suitable art recognized adhesive might be used on the Yankee dryer.
  • Preferred adhesives include poiyvinyl alcohol with suitable plasticizers, glyoxylated polyacrylamide with or without poiyvinyl alcohol, and polyamide epichlorohydrin resins such as Quacoat A-252 (QA252),
  • Betzcreplus 97 (Betz+97) and Calgon 675 B.
  • Suitable adhesives are widely described in the patent literature. A comprehensive but non-exhaustive list
  • the final product may be calendered or uncalendered and is usually
  • the products according to the present invention may be subjected to any art recognized converting operations, including embossing, printing, etc.
  • a nascent web was formed on a Crescent-forming machine using a
  • the basis weight of the sheet on the Yankee dryer was 8.5 lbs/3000 ft 2 .
  • the sheet was pressed onto a Yankee dryer with a suction
  • the vacuum in the suction roll was nominally 0.22 bar.
  • the suction pressure roll was replaced by a
  • the sheet was conditioned before the shoe press with a suction turning roll having the same size and open area as the suction pressure roll.
  • the suction turning roll vacuum was nominally equivalent to the level used during the suction pressure roll experiments.
  • the web was pressed onto the Yankee with a shoe press.
  • a shoe press In order to obtain precise sheet solids data after the shoe press or the suction
  • Figure 12 depicts a plot of sheet solids versus line loading.
  • the typical 120 mm shoe shows no solids benefit versus the suction pressure roll at present operating iine load limits of current Yankee dryers (i.e., approximately, 87.5 kN/m), while the 50 mm pressure optimized shoe press shows an advantage of several
  • Figures 13-15 illustrate a method for maximizing water removal in a press nip in accordance with another embodiment of the present invention.
  • the present embodiment involves a conventional wet pressing (CWP)
  • the present embodiment uses a shoe press, preferably a controlled crown roll with a flexible shell and a concave shoe
  • the present embodiment further includes a belt or blanket (100) having a void volume that enhances
  • void volume can be achieved by a number of blanket configurations, including, but not limited to, those made by grooving, blind drilling and the like.
  • the total void volume of the belt or blanket for use according to the present invention is preferably about 50 to about 3000 cm 3 /m 2 , more preferably about 100 to about 1000 cm 3 /m 2 , most preferably from about 200 to about 500 cm 3 /m 3 .
  • Blankets for use according to the present invention can include any art
  • blankets disclosed by E.J. Justus and D. Cronin in Tappi disclose blankets disclosed by E.J. Justus and D. Cronin in Tappi.
  • the groove width is about 0.01 to about 0.03 in.
  • the land width is about 2 to about 20 times the groove width and the groove depth is about 2 to about
  • the belts include groove widths of about 0.5 to about 1 mm and a void volume of about 100 cc/m 2 to about 500 cc/m 2 .
  • blankets disclosed by P. Slater and K. Fitzpatrick in the 84 th Annual Meeting of the Technical Section, CPPA, January 1998 which is incorporated herein by reference, include grooved belts that provide a press dryness about 1 % to about 3% greater than the press dryness obtained with a similar smooth belt.
  • the belts have groove widths of about 0.58 to about 0.79 mm and a void volume of about 200 cc/m 2
  • grooved belts that provide a press dryness about 1 % greater than the dryness obtained with a blind drilled belt.
  • the grooved belt has an open area of about a 20.3% and a void volume of about 260 cc/m 2 ,
  • the blind drilled belt has an open area of about 21 % and a void volume of
  • blind drilling involves drilling holes into a smooth blanket, as will be understood by one of skill in the art.
  • the blind drilled blanket preferably has a plurality of holes sequentially
  • the blind drilled blanket can take a variety of configurations.
  • the hole depth, hole diameter, hole spacing, hole angle, hole geometry, row spacing and/or row pattern can be varied.
  • the hole depth can range from about 0.2 to about 10 mm, more preferably about 0.5 to about 5 mm, most preferably from about 0.5 to
  • the hole depth can extend partially or completely through
  • the hole diameter can range from about 0.2 to about 10 mm, more preferably about 0.5 to about 5 mm, most preferably from about 1 to about 3
  • the hole spacing can range from about 1 to about 20 mm between
  • the hole angle (i.e., the angle measured from the surface of the belt material counterclockwise to the side of the hole) can range from about 45 to about 135 degrees along any wall in either the machine or cross-machine, more preferably about 70 to about 110 degrees, most preferably from about
  • the row spacing can range from about 1 to about 20 mm, more
  • the hole geometry can be curved, linear or curvilinear, e.g. round,
  • square, elliptical, polygonal, and the row pattern can be such that the holes in each row are aligned in the cross-machine direction, offset in the cross- machine direction, aligned in the machine direction, offset in the machine
  • each of the holes can have a different configuration, or one or more individual or set of holes can have the same configuration as one or more
  • hole pattern form any type of geometric or other pattern, for example, the pattern can be random.
  • Nip compression of the grooved blanket and the press felt causes a hydraulic pressure gradient in the machine direction, which improves water flow and removal.
  • the grooved blanket preferably has a plurality of grooved sections sequentially arranged in the cross-machine direction that circumscribe the blanket to cause machine direction water movement.
  • the grooved blanket can take a variety of configurations. For example, the groove depth, groove
  • the groove depth can range from about 0.1 to about 8 mm, more preferably about 0.2 to about 5 mm, most preferably from about
  • the groove width can range from about 0.1 to about 6 mm, more preferably about 0.2 to about 4 mm, most preferably from about 0.4 to about 3
  • the groove bevel (i.e., the angle measured from the surface of the belt material counterclockwise to the side of the groove minus 90°) can range from about 0 to about 45°, more preferably about 0 to about 30°, most preferably from about 0 to about 20°.
  • the groove angle can range from about 45 to about 135 degrees (with 90 degrees being orthogonal to the cross-machine direction), more preferably
  • the land width can range from about 0.2 to about 25 mm, more
  • the open area can range up to 80% of the total blanket area, more preferably about 15 to about 50%, most preferably from about 20 to about
  • the groove pattern can be such that the grooves in each row are
  • grooves need not have the same configuration, rather, all the grooves can have a different configuration
  • one or more individual or set of grooves can have the same configuration as one or more other individual or set of grooves. Further, there is no
  • the groove pattern form any type of geometric or other pattern, for example, the groove placement can also be random.
  • Blankets having the disclosed void volume will be readily apparent to the skilled artisan. Such blankets can include any physical arrangement as long as the void space requirements are satisfied. Blankets for use in the
  • present invention may be manufactured by any art recognized process, including but not limited to, casting molding, laser engraving, etc.
  • EXAMPLE 2 A punch press was used to perform dewatering experiments with different belt structures. An AMFIex 3S felt manufactured by Appleton Mills Corporation was used to dewater the paper web. The web basis weight was
  • Web moisture was controlled to 19.3% dryness by rewetting moist webs using a water spray. The webs were
  • a smooth belt, a blind drilled belt and a grooved belt were used in the
  • the blind drilled belt had a bore area of 3.82 mm 2 ,
  • the grooved belt had a groove width of 0.66 mm, a groove depth of
  • the punch press was operated such that the average nip pressure was

Abstract

The present invention is a method for maximizing water removal from an absorbent web in a press nip. The present invention uses a pressing unit having a blanket with a void volume and with a pressure profile that maximizes water removal in the press section or on the Yankee dryer of a paper machine. The pressure profile of the pressing unit according tho the present invention has a very steep pressure drop at and/or following the exit of a pressure distribution curve in order to maximize water removal by minimizing rewet of the web. The improved pressure profile according to the present invention results in increased water removal and/or improved line speed. The void volume further increases water removal and/or improves line speed.

Description

METHOD FOR MAXIMIZING WATER REMOVAL IN A PRESS NIP RELATED CASES
This application is a continuation-in-part of copending application Serial No. 09/191 ,376, filed November 13, 1998. FIELD OF INVENTION
The invention relates to a method for maximizing water removal from an absorbent paper web in a press nip. More particularly, the present invention relates to the use of a shoe press on the Yankee dryer with a pressure profile that maximizes water removal. Still more particularly, the present invention relates to a method for utilizing a very steep pressure drop at and/or following the exit of a nip curve in order to maximize water removal by minimizing rewet. Finally, the present invention relates to a method for increasing paper machine speed by utilizing a press section that maximizes water removal. BACKGROUND OF THE INVENTION
In modern society, bath tissue, paper towels, facial tissue, and paper napkins (hereinafter referred to as packaged paper products) have been remarkably successfully consumer products. The success of these paper products stems from the ability of manufacturers to consistently enhance product attributes at lower cost and to meet volume demands on a timely basis. Packaged paper products offer consumers an array of attributes necessary to such jobs as performing the daily tasks of wiping up spills, personal cleansing, and cleaning household goods. For example, paper towels are engineered to be absorbent and strong while wet whereas bath tissue products are expected to be soft to the touch yet strong while in use. Absorbency and softness are inversely related to strength, often making it difficult to obtain the right balance of attributes. Accordingly, significant research and development efforts are routinely expended to enhance the quality of these products while continuing to reduce cost by, for example, improving the production of these products. Although numerous schemes have been developed and patented, the search by R&D departments continues to seek out new and innovative methods for improving -these products.
There are numerous methods described in the patent literature for improving the quality of packaged paper products. One of the earliest known methods to enhance the quality of consumer paper products is described in U. S. Patent No. 3,301 ,746 by Sanford and Sisson, assigned to Procter and Gamble Corporation, and incorporated herein by reference in its entirety.
This patent describes a papermaking scheme for enhancing product quality by avoiding overall web compression and by using a pattern array of densified regions in the xy plane of the sheet to enhance product strength.
Other early methods for improving the quality of packaged paper products are described in U.S. Patent No. 3,812,000 by Salvucci and Yiannos and U.S. Patent No. 3,821 ,068 by Shaw. These patents are assigned to Scott Paper Company, each of which is incorporated herein by reference in its entirety. Shaw discloses a papermaking scheme for producing soft tissue by avoiding mechanical compression until the sheet has been dried to at least 80% solids. Salvucci and Yiannos disclose a technique for producing a soft tissue structure by avoiding mechanical compression of an elastomeric containing fiber furnish until the consistency of the web is at least 80% solids.
Thicker more absorbent structures can be made using a low batting papermaking felt as described in U.S. Patent No. 4,533,457 by Curran et al., assigned to Scott Paper Company, and incorporated herein by reference in its entirety. U.S. Patent Nos. 5,591 ,305 and 5,569,358 by Cameron, assigned to James River Corporation, and incorporated herein by reference in their entirety, disclose a low-batting, high-bulk-generating felt with improved dewatering capabilities. A more recent method for improving the quality of a through-air-dried sheet is described in U.S. Patent No. 4,440,597 by Wells and Hensler, assigned to Procter and Gamble Company, and incorporated herein by reference in its entirety. This patent describes a method for increasing the stretch of a paper web by operating the forming section of a paper machine faster than the through air dryer section of the paper machine. As a result of the speed differential, the paper web is inundated into the through air-dryer- fabric leading to enhanced stretch and absorbency properties in the base sheet and resulting product.
Fibers and chemicals can be used to enhance the quality of packaged paper products. For example, U.S. Patent No. 5,320,710 by Reeves et al., assigned to Fort James Corporation, and incorporated herein by reference in its entirety, describes a new furnish combination extracted from the species Funifera of the genus Hesporaloe in the Agavaceae family. This furnish has fibers which are very long and which have very fine-geometrical attributes known to enhance tissue and towei performance. U.S. Patent No. 3,755,220 by Freimark and Schaftlein, assigned to Scott Paper Company, and incorporated herein by reference in its entirety, describes a debonding scheme for maintaining wet strength while reducing product dry strength-a method known to enhance the handfeel of towel products.
The use of bulking fibers can improve the quality of the final end product. U.S. Patent No. 3,434,918 by Bernardin, U.S. Patent No. 4,204,504 by Lesas et al., U.S. Patent No. 4,431 ,481 by Drach et al., U.S. Patent No. 3,819,470 by Shaw et al., and U.S. Patent No. 5,087,324 by Awofeso et al. disclose the use of bulking fibers in papermaking webs to improve product attributes like thickness, absorbency, and softness. These aforementioned patents are incorporated herein by reference in their entirety.
U.S. Patent No. 5,348,620 by Hermans et al., assigned to Kimberly- Clark Worldwide Inc., and incorporated herein by reference discusses a high consistency/high temperature fiber-treatment-process using a disperser to improve product attributes. To improve tissue softness, several approaches are available to the papermaker such as using certain species of hardwood like eucalyptus in stratified webs as disclosed in U.S. Patent No. 4,300,981 by Carstens and U.S. Patent No. 3,994,771 by Morgan et al. The last two patents are incorporated herein by reference in their entirety. These aforementioned patents describe just a few of the many methods developed over the last thirty years to enhance the quality of packaged paper products. There are also numerous schemes for enhancing the productivity of paper machines. For example, gap formers have been developed to enhance sheet drainage ultimately leading to increased machine speed. New developments in Yankee hood design and Yankee cylinder design have allowed improvements in heat transfer coefficients and mass transfer coefficients, ultimately leading to enhanced machine speeds. New developments in forming fabrics, e.g., multi-layer and triple-layer forming fabrics, have resulted in improved drainage, better fabric life, and enhanced fiber support. These factors translate into enhanced machine speed and productivity. Improvements in press felts, e.g. Scapa's SPECTRA ™ felt concept of using a soft polyurethane sandwich near the base of the felt or the use of stratified batting, have led to improvements in felt life, reductions in break-in time, and improvements in water removal at wet presses. These improved press-felt developments have ultimately translated into improved machine speed and productivity. Improvements in Yankee creping adhesives have been helpful to enhance blade wear and reduce sheet plugging.
Continuos creping doctors have alleviated the need to frequently change doctor blades. The last two aforementioned developments have led to improvements in machine speed, reductions in down time, and reductions in paper waste. In spite of all these advances, methods are sought to enhance productivity.
The present invention improves the efficiency of known water removal methods by adding one or more pressing units to the production paper machine, in place of or in conjunction with a suction pressure roll. "Pressing units" according to the present invention include those units that physically engage a belt or pressing blanket, which contacts the impression fabric or felt upon which the web travels. "Foraminous endless fabric" as defined in accordance with the present invention includes either an impression fabric or felt. "Pressing unit" as defined in accordance with the present invention includes any press members allowing deformation of the pressing blanket/impression fabric and/or felt/web sandwich to result in asymmetric pressure profiles. These pressing units including pressing blankets are generally discussed in the literature as "shoe presses." Pressing units according to the present invention do not include suction pressure rolls since they lead to symmetrical pressure distributions frequently mathematically described by sine or haversine functions. Shoe presses have been used to increase water removal at wet presses, ultimately leading to increased machine speed for linerboard grades and more recently, newsprint and fine paper grades. The idea of extending the time in a press nip as a means to enhance water removal is not a new idea. Nissan in 1954 published a paper in Tappi, Vol. 37, No.12, p.597 (1954) suggesting that the use of extended time in a press nip would enhance the water removal performance of a press. Over twenty-five years, ago Busker published an early paper in Tappi, Vol. 54, No.3, p.373 (1971) on the use of extended nip times, as a means to enhance water removal. Beloit Corporation commercialized the first open belt wide shoe press on a linerboard machine in 1980 as described in an article by J. Blackledge presented during the 2nd International Pira Conference, entitled 'Modem Technologies in Pressing and Drying', Nov 6-8, 1990, p. 1. The aforementioned three articles are herein incorporated by reference in their entirety. Figure 1 shows a typical closed belt wide shoe press (see Figure 2 in an article entitled "New Pressing Technologies for Multiply Board" by J. Breiten in 81st Annual Meeting, Technical Section, CPPA, p. A137 for a more detailed drawing). A wide shoe press as described in the literature is essentially a controlled crown roll with a flexible shell and a concave shoe hydrodynamically loaded against each other. The belt or blanket is usually a fabric reinforced polyurethane-coated structure that can be grooved or blind drilled for more efficient water removal. The inside of the belt is generally lubricated with oil, which develops a hydrodynamic film as it passes over the shoe and reduces wear/friction in both surfaces. Wide shoe press nips are on average 5 to 10 times longer than conventional roll press nips (generally, 5" - 10" versus 1" - 2"). Water deflectors (not shown) on the outside surface will dewater the blanket. By utilizing such a wide nip, loads up to 10,000 pli are possible without the risk of damaging blankets and felts or crushing the sheet. The exit side of the shoe features a sharply curved nose designed to pull the sheet directly out of the nip and away from the felt, thus reducing rewet and improving sheet dryness. U.S. Patent No. 4,931 ,142 describes certain advantages to this type of take off angle in conjunction with long press nips. Rolls do not normally support the belt loop of the wide shoe press. The loop generally is closed off with special head assemblies for containing the oil.
Numerous schemes for improving the operation of shoe presses have been developed over the years. For example, in U.S. Patent No. 5,043,046 by Laapotti and assigned to Valmet Corporation, U.S. Patent No. 4,625,376 by Schiel et al. and assigned to Voith Corporation, and U.S. Patent No. 4,673,461 by Roerig and assigned to Beloit Corporation, methods are described to enclose the shoe press in order to contain the oil within the unit. The previous three patents are incorporated herein by reference. U.S. Patent
No. 5,167,768 by Cronin and Roerig and assigned to Beloit Corporation and U.S. Patent No. 5,582,689 by Rolf Van Haag and Hans-Rolf Conard and assigned to Voith Corporation describe methods for varying the pressure distribution in a shoe press. This capability avoids the need to offset the center of loading or reshape the shoe to change the pressure distribution.
These last two patents are also incorporated herein by reference. U.S. Patent No. 5,693,186 by Vallius, assigned to Valmet Corporation, and incorporated herein by reference describes a tension link scheme for containing the loading within the framing of the shoe press apparatus. This scheme ultimately avoids the need to fortify flooring when operating at high line loads. These are just a few of the many developments that have led to improved operating shoe presses.
In the art of pressing linerboard, newsprint, and fine paper webs with a shoe press, a long shoe with a gradual pressure rise is desirable for good dewatering and enhanced bulk properties. This is especially true for flow controlled webs. Linerboard and to a certain extent newsprint and fine paper have flow controlled pressing conditions. Flow controlled pressing conditions occur when the time in the nip becomes an important factor determining the amount of water removed from the web. High pressure can be attained with these long shoes but it requires high line loads. Figure 2 shows the relationship between peak pressure (i.e., the maximum pressure in the nip) and line load (i.e., the total force divided by linear width) for shoe press nips compiled from an extensive but not exhaustive search of the literature. Table I describes the literature references used to develop Figure 2. Table I: References Used to Generate Figure 2.
Figure imgf000009_0001
The graph in Figure 2 shows that shoe presses normally operate at
high line load conditions, usually greater than 270kN/m and at high peak pressures. It also shows that shoe presses are not operated at low line loads and at high peak pressures (e.g., see the crosshatched region in Figure 2).
In the art of making tissue by the conventional wet pressing operation,
Yankee dryers are loaded with suction pressure rolls to remove water from the tissue web and attach the web to the dryer for further processing by the creping operation. The pressure distribution in the suction pressure roll nip is symmetrical in shape and is described mathematically by a sine or a haversine curve. Suction pressure rolls loaded to a Yankee dryer are
routinely run at line loads less than 100 kN/m and at peak pressures of less than 4500 kN/m2. In the lower left-hand corner of Figure 2 some typical peak pressure versus line load data for suction pressure rolls are shown. The
deflection of large, conventional Yankee dryers due to hoop stress levels
limits the line load to less than about 100 kN/m. As a result, it is very difficult to attain high peak pressures in the nip at these low line loads, since the pressure distribution cannot be altered. This limitation has extreme consequences for tissue grades since they are pressure controlled, i.e., the flow resistance in the web is low due to the use of high freeness furnishes and low basis weight webs, thus it is believed that peak pressure, not time in
the nip, controls press dewatering. These suction pressure rolls suffer from other disadvantages. For example, since the nip diverges after the maximum
pressure is achieved, rewet can occur for a large part of the press nip. A
typical suction pressure roll curve appears in Figure 3, where nip divergence is apparent. Also, the suction pressure roll unit is not flexible so that the line load needs to be fixed and matched to a given Yankee crown condition in order to obtain a uniform nip profile across the machine. Furthermore, since
the loading cylinders are located at each end of the pressure roll, profiling
capabilities are very limited.
The use of conventional shoe presses on a Yankee dryer at the maximum hoop stress limit of 100kN/m would lead to very low peak pressures as Figures 2 and 3 demonstrate. For example, with a 120 mm shoe at 100
kN/m, the typical peak pressure is on the order of 1700 kN/m as Figure 3 demonstrates. Since the press nip for low weight tissue and towel grades is pressure controlled, the very low peak pressure could cause a decrease in
post press dryness, ultimately causing a loss in production. The counter roll
in a conventional shoe press is small by comparison to the diameter of a Yankee dryer. As a result, the use of a conventional shoe shape would make it very difficult to remove the felt/fabric from the sheet at the nip exit. Therefore, conventional shoe shapes and conventional felt/fabric takeoff angles would exacerbate rewet for low weight absorbent products.
Currently, there are no commercial uses of shoe press technology in the production of absorbent paper products. U.S. Patent No. 5,795,440 by Ampulski et al., and U.S. Patent No. 5,776,307 by Ampulski et al.-both assigned to Procter and Gamble Corporation and both incorporated herein by
reference, describe a scheme for making a shaped web by pressing an embryonic web into an imprinting fabric between two felts. These patents use
a shoe press assembly in the preparation of a wet pressed paper web. Ampulski et al., like others using pressing units, teaches the use of longer
conventional press nips. Ampulski et al. discloses that the nip length is
greater than 3.0 inches and may be as long as 20.0 inches. Ampulski et al. achieves this extended nip length through the use of a shoe press. Ampulski et al., like all previous users of shoe presses, fails to consider the use of increased peak pressure.
International patent application WO 97/43483 by Hermans and
Friedbaurer, assigned to Kimberly-Clark Worldwide, Inc., and incorporated herein by reference discloses that extended nip presses, while having been
successfully used for making paperboard, have not been used to make low
density paper products such as tissue because the high pressure and longer
dwell times in an extended nip press serve to density the sheet beyond that experienced by conventional tissue wet pressing methods. Hermans and
Friedbaurer overcome the increased density due to extended nip pressing by incorporating modified resilient fibers (e.g., chemically cross-linked cellulosic fibers) in the web and by wet micro-shaping the web. They also disclose shoe lengths typically in the range of 5 to 10 inches. Like Ampulski et al., Hermans and Friedbaurer do not consider critical peak pressures or line loads
as important.
U.S. Patent No. 5,393,384 by Steiner et al., and assigned to J.M. Voith, GmbH (hereinafter "the '384 patent") generally describes the use of a
shoe press in the production of a tissue web. The '384 patent describes the use of a shoe press preceding or contacting a Yankee drying cylinder. The shoe press is used in conjunction with an impermeable belt to reduce remoistening of the sheet by the felt. These authors used the impermeable
belt since they state: "the prevailing opinion in selecting suitable drying presses in contingence on the web thickness so far has been that for drying
thin webs there are only simple roll presses suited which generate a sufficiently high contact pressure for a short time, thus optimally removing the water from a thin web (tissue web) due to the short path, whereas shoe type
presses are suited essentially for drying thick, heavy webs, since they
generate a persistent pressure which allows the water sufficient time for the
considerable longer path in leaving the web." Critical peak pressure and line loads are not discussed in the disclosure. Since the shoe press described in
this disclosure is conventional, a pressure curve for this type of shoe press is most likely similar to the "typical shoe press curve" illustrated in Figure 3.
Voith, the assignee of the '384 patent, continues to develop the use of a shoe press for the production of paper products. U.S. Patent No. 5,500,092 by Schiel describes a tissue making machine using a triple press nip where
the second nip is a shoe press nip. The criticality of pressure distribution shape and peak pressure/line load magnitudes are not disclosed in the '092 patent. In the September 1997 article W. Schuwerk, "Shoe Presses and
Sleeves for Newsprint-Concepts and Initial Operating Experience," PaperAge, Pp. 18-23, Voith described the advantages of their NIPCOFLEX shoe press.
According to that article, "(T]o obtain optimum product characteristics,
dewatering in the press must [therefore] show as flat a pressure gradient as possible." In fact, the shoe press described in the article refers to the third
section of a newsprint paper machine operating at a line loading of 850 kN/m and a peak pressure of -5.6 MPa, typical of standard conventional shoe designs and well outside the range of the present invention.
U.S. Patent No. 4,931 ,142 by Steiner, Muller, Schiel, and Flamig, assigned to Voith Corporation and incorporated herein by reference in its
entirety describes a method of eccentrically arranging a press blanket with
respect to the press plane. This arrangement enables the blanket upon
leaving the press nip to immediately move steeply downward and away from the sheet in order to reduce remoistening of the web. Methods of varying the
felt angle with respect to the traveling web in a double felted press nip were
disclosed to avoid remoistening the sheet and for quick release of the sheet from the felt. Steiner et al. also discloses that the joint path of travel of the paper web, felt, and blanket can be made substantially shorter than prior art.
By utilizing the Steiner et al. invention, the joint travel of the felt, web, and blanket can be made equal to zero, i.e., the web can detach itself from the felt directly at the emergence from the press nip. Steiner et al. does not address low line loads and high peak pressures needed for optimum shoe press
performance on Yankee dryers. It also does not disclose the need to taper
the press shoe to achieve minimized rewet. U.S. Patent No. 5,556,511 by Bluhm and Gotz, assigned to Sulzer-
Escher Wyss, and incorporated herein by reference describes a process for
making toilet tissue webs whereby a web is wet pressed in a heated pressing arrangement. The heated pressing arrangement can be a shoe press. This disclosure does not address the importance of proper choice of peak pressure, line load, and shoe shape for making absorbent products at high speeds. In fact, the critically of line loads and peak pressures is not
discussed. Bluhm and Gotz like all previous users of shoe presses, fails to consider the use of increased peak pressure at low line loads as a means to
improve water removal.
U.S. Patent No. 4,973,384 by Crouse, Pulkowski, and Porter, assigned to Beloit Corporation, and incorporated herein by reference describes a
process for using a heated extended nip press for optimizing sheet properties
without lamination. To accomplish the aforementioned task Crouse et al. found that by application of pressure for an increased period of time, the
increased residence time enables the removal of more water from the formed web. As a result, these authors teach toward the use of a conventional long shoe design. They also found that for a heated extended nip press by "gradually decreasing pressure in machine direction toward the trailing edge of the shoe, rapid flashing of steam from the emerging pressed web was
avoided." As a result these authors teach away from the use of a heavy peaked pressure distribution at the exit side of a shoe press nip.
WO 97/16593 by Wedel and Worcester incorporated herein by reference discloses an impulse drying method for tissue structures using a
shoe press and an induction heater. This disclosed impulse-drying method is
intended to replace the Yankee dryer with its associated problems. These authors list the issues with Yankee dryers as being limited in surface temperature to 185°F, as being limited in line load to 500 pli due to shell thickness limitations, and as being limited in roll diameter. These authors state that shoe length is typically ten inches for the impulse drying unit. The line loads disclosed are 1000 pli to10,000 pli. As a result, this application teaches away from the combined use of a low line load with a substantial
peak pressure.
Contrary to the current state of the art, the present inventors have,
quite unexpectedly, found that in the production of absorbent paper products,
the use of a steep, sharp pressure gradient and controlled separation when producing absorbent paper can improve dewatering efficiency without
adversely affecting product properties. An example of the pressure profile of the new shoe design for absorbent paper production according to the present invention is illustrated in Figure 3.
The present inventors unexpectedly discovered that good sheet dewatering and appropriate bulk/strength properties for low weight absorbent products could be attained with this pressure optimized shoe press. The optimized pressure conditions can be achieved according to the present
invention by shaping the shoe, tilting the shoe in the shoe press, reducing the
length of the shoe in the shoe press, and/or tapering the exit side of the shoe. In addition, these conditions can also be achieved by deflecting the pressing
blanket from the web carrying foraminous-endless-fabric at a point nearly simultaneous with separation of the foraminous-endless-fabric from the nascent web, thereby reducing rewet. These techniques enable the pressure optimized shoe press according to the present invention to achieve improved
dewatering while maintaining bulk with line loads less than about 240kN/m and peak pressures greater than about 2000 kN/m2. SUMMARY OF THE INVENTION Further advantages of the invention will be set forth in part in the
description, which follows and in part will be apparent from the description.
The advantages of the invention may be realized and attained by means of
the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the foregoing advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is disclosed:
An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric; means for depositing a nascent web for the absorbent paper sheet on
the foraminous endless fabric;
a moving endless pressing blanket; a Yankee drying cylinder; and a pressing unit engaging the pressing blanket adapted to urge the
nascent web for the absorbent paper sheet on the foraminous endless fabric
into engagement with the Yankee drying cylinder thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m. There is further disclosed:
An apparatus for forming an absorbent paper sheet product comprising: a moving foraminous endless fabric;
means for depositing a nascent web for the absorbent paper sheet on the foraminous endless fabric;
a moving endless pressing blanket;
a Yankee drying cylinder; and
a pressing unit engaging the pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric into engagement with the Yankee drying cylinder thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m, the pressing unit being configured to disengage the web from the foraminous endless fabric such that rewet of the nascent web by the foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the properties of the foraminous endless
fabric and the nascent web.
There is still further disclosed:
An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric;
means for depositing a nascent web for the absorbent paper sheet on the foraminous endless fabric;
a moving endless pressing blanket; a Yankee drying cylinder; and
a pressing unit engaging the pressing blanket adapted to urge the
nascent web for the absorbent paper sheet on the foraminous endless fabric into engagement with the Yankee drying cylinder thereby forming a nip, the
pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m,
the pressing unit being configured to both disengage the web from the foraminous endless fabric and disengage the foraminous endless fabric from the pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches zero.
There is still further disclosed: An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric; means for depositing a nascent web for the absorbent paper sheet on
the foraminous endless fabric; a moving endless pressing blanket; a transfer cylinder; and
a pressing unit engaging the pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric into engagement with the transfer cylinder thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m. There is still further disclosed: An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric;
means for depositing a nascent web for the absorbent paper sheet on the foraminous endless fabric;
a moving endless pressing blanket; a transfer cylinder; and a pressing unit engaging the pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric into engagement with the transfer cylinder thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about
2000 kN/m2.
There is still further disclosed:
An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric;
means for depositing a nascent web for the absorbent paper sheet on the foraminous endless fabric; a moving endless pressing blanket; a backing roll; and a pressing unit engaging the pressing blanket adapted to urge the nascent web for the absorbent paper sheet on the foraminous endless fabric
into engagement with the backing roll thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about
2000 kN/m2 at an overall line load of less than about 240 kN/m. There is still further disclosed:
A method of making an absorbent paper sheet product comprising:
depositing a nascent web for the absorbent paper sheet product on a
moving foraminous endless fabric; and contacting the moving foraminous endless fabric bearing the deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of
less than about 240 kN/m.
There is also disclosed:
A method of making an absorbent paper sheet product comprising:
depositing a nascent web for the absorbent paper sheet product on a
moving foraminous endless fabric; contacting the moving foraminous endless fabric bearing the deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip, the pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m; transferring the web to a Yankee drying cylinder; and
creping the web from the Yankee drying cylinder. There is finally disclosed:
A method of making an absorbent paper sheet product comprising:
depositing a nascent web for the absorbent paper sheet product on a moving foraminous endless fabric;
contacting the moving foraminous endless fabric bearing the deposited
nascent web with a shoe press thereby forming a nip between the shoe press and a Yankee drying cylinder, the shoe press being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m; disengaging the web from the foraminous endless fabric in the nip onto
a Yankee drying cylinder; drying the web on the Yankee drying cylinder; and
creping the web from the Yankee drying cylinder.
The accompanying drawings are included to provide a further
understanding of the invention and are incorporated in and constitute a part of the specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates a side view of a typical stand alone shoe press. Figure 2 illustrates the relationship between peak pressure and line load for a variety of shoe press arrangements found in the literature, as well as for Yankee suction pressure rolls.
Figure 3 illustrates nip pressure profiles for a suction pressure roll, a
typical shoe press, and a shoe press made according to the present
invention.
Figure 4 illustrates one conventional wet press processing apparatus.
Figure 5 illustrates one conventional through-air-drying processing
apparatus.
Figure 6 illustrates a typical pressure profile in the nip of a suction
pressure roll, backing roll, or transfer cylinder according to the prior art.
Figure 7 illustrates a pressure profile in the nip of a shoe press. Figure 8 illustrates a preferred pressure profile in the nip of a shoe press where the negative pressure corresponds to the vacuum level in the
felt. Figure 9 illustrates a shoe press with a large diameter transfer cylinder
where the felt rides the web causing rewet after the press nip.
Figure 10 illustrates a tapered shoe in a shoe press with a large diameter transfer cylinder where the felt is rapidly separated from the web but
not from the pressing blanket.
Figure 11 illustrates a tapered shoe in a shoe press with a large diameter transfer cylinder where the felt is simultaneously stripped from the sheet and from the pressing blanket on the exit side of the nip. Figure 12 shows a plot of cold Yankee press solids versus line loading for a conventional 120 mm shoe, for a 50 mm shoe made according to the present invention, and for a suction pressure roll.
Figure 13 illustrates a side view of a typical stand alone shoe press
with a blanket having void space.
Figure 14 illustrates a blind drilled blanket or belt.
Figure 15 illustrates a grooved blanket or belt. DETAILED DESCRIPTION
In the production of absorbent paper products, paper web drying
efficiency and paper web moisture removal directly affect machine speed, and
therefore have a significant effect on the productivity that can be attained on a papermachine. The present invention improves paper web moisture removal through the controlled use of a pressing unit in conjunction with a backing roll and/or a transfer cylinder or Yankee drying cylinder. An absorbent paper web as defined herein includes bath tissue, paper towels, paper napkins, wipers, and facial tissue. The basis weight of such products and their base sheets
are in the range of about 8 lb/3000ft2 to about 50 lb/3000ft2.
According to the present invention, absorbent paper may be produced
using any known method or papermaking scheme. The most common
papermaking methods are (I) conventional wet pressing (CWP) and (II)
through-air-drying (TAD), in a conventional wet press process, i.e., apparatus
(10), as exemplified in Figure 4, a furnish is fed by means not shown through conduits (40, 41 ) to headbox chambers (20, 20'). A web (W) is formed on a conventional wire former on fabric (12), supported by rolls (18, 19), from a
liquid slurry of pulp, water and other chemicals. Materials removed from the web through fabric (12) in the forming zone are returned to silo (50), from
saveall (22) through conduit (24). The web is then transferred to a moving felt (14), supported by roll (11 ) for pressing and drying. Materials removed from
the web during pressing or from the Uhle box (29) are collected in saveall (44)
and fed to white water conduit (45). The web is pressed by suction pressure roll (16) against the surface of a rotating Yankee dryer cylinder (26), which is
heated to cause the paper to substantially dry on the cylinder surface. The moisture within the web as it is laid on the Yankee surface causes the web to transfer to the surface. Liquid adhesive may be applied to the surface of the
dryer to provide substantial adherence of the web to the creping surface. The
web is then creped from the surface with a creping blade (27). The creped
web is then usually passed between calender rollers (not shown) and rolled up on reel (28) prior to further converting operations, for example, embossing.
A web may alternatively be subjected to vacuum deformation on an
impression fabric, alone or in conjunction with other physical deformation
processes, and a dewatering step which removes water from the web to a solids content of at least about 30% without the need for overall physical compression. This type of process is conventionally referred to as a through- air-drying process or TAD process. This process is generally described in
U.S. Patent Nos. 3,301 ,746 to Sanford et al. and 3,905,863 to Ayers, which are incorporated herein by reference in their entirety. As an example, one conventional TAD process is illustrated in Figure
5. In this process, fibers are fed from a headbox (10) to a converging set of forming wires (20,30). In this twin wire forming arrangement water is removed
from the web by centrifugal forces and by vacuum means. The wet nascent web is cleanly transferred to forming wire (30) via Uhle box (40). The web
can be optionally processed to remove water by vacuum box (50) and steam
shroud (60). The web is carried along forming fabric (30) until it is transferred to a TAD fabric (70) at junction (80) by means of a vacuum pickup shoe (90). The web is further dewatered at dewatering box (100) to increase web solids. Besides removing water from the web, vacuum pickup shoe (90) and
dewatering box (100) inundate the web into TAD fabric (70) causing bulk and absorbency improvements.
Further enhancements in bulk and absorbency can be obtained by
operating the speed of the forming section (i.e., the speeds of forming fabrics
20 and 30) faster than the speed of TAD fabric (70). This is referred to as
fabric/fabric creping. In this manner the web is inundated and wet shaped into the fabric creating bulk and absorbency. Thickness created by wet shaping is more effective in generating absorbency (i.e. less structural
collapse) than thickness created in the dry state, e.g., by conventional embossing. The web is then carried on TAD fabric (70) to drying unit (110) where heated air is passed through both the web and the fabric to increase the solids content of the web. Generally, the web is 30 to 95% dry after exiting drying unit (110). In one process, the web may be removed directly from TAD fabric (70) in an uncreped state. In the embodiment shown in
Figure 5, the web is transferred from TAD fabric (70) to Yankee dryer cylinder
(130) and is creped from dryer cylinder (130) via creping blade (150). The
creped web is then usually passed between calender rollers (160) and rolled
up on reel (170) prior to further converting operations, for example, embossing to make roll products.
According to the present invention, an absorbent paper web can be made by dispersing fibers into aqueous slurry and depositing the aqueous
slurry onto the forming wire of a paper making machine. Any art recognized forming scheme might be used. For example, an extensive but non- exhaustive list includes a crescent former, a C-wrap twin wire former, an S- wrap twin wire former, a suction breast roll former, a fourdrinier former, or any
art recognized forming configuration. The particular forming apparatus is not
critical to the success of the present invention. The forming fabric can be any
art recognized foraminous member including single layer fabrics, double layer fabrics, triple layer fabrics, photopolymer fabrics, and the like. Non- exhaustive background art in the forming fabric area include U.S. Patent Nos.
4,157,276; 4,605,585; 4,161 ,195; 3,545,705; 3,549,742; 3,858,623;
4,041 ,989; 4,071 ,050; 4,112,982; 4,149,571 ; 4,182,381 ; 4,184,519; 4,314,589; 4,359,069; 4,376,455; 4,379,735; 4,453,573; 4,564,052; 4,592, 395; 4,611 ,639; 4,640,741 ; 4,709,732; 4,759,391 ; 4,759,976; 4,942,077;
4,967,085; 4,998,568; 5,016,678; 5,054,525; 5,066,532; 5,098,519; 5,103,874; 5,114,777; 5,167,261 ; 5,199,467; 5,211 ,815; 5,219,004; 5,245,025; 5,277,761 ; 5,328,565; and 5,379,808 all of which are incorporated
herein by reference in their entirety. The particular forming fabric is not critical
to the success of the present invention. One forming fabric found particularly
useful with the present invention is Appleton Mills Forming Fabric 2184 made
by Appleton Mills Forming Fabric Corporation, Florence, MS. Papermaking fibers used to form the absorbent products of the
present invention include cellulosic fibers commonly referred to as wood pulp
fibers, liberated in the pulping process from softwood (gymnosperms or coniferous trees) and hardwoods (angiosperms or deciduous trees). Cellulosic fibers from diverse material origins may be used to form the web of
the present invention. These fibers include non-woody fibers liberated from
sugar cane, bagasse, sabai grass, rice straw, banana leaves, paper mulberry (i.e., bast fiber), abaca leaves, pineapple leaves, esparto grass leaves, and fibers from the genus Hesperaloe in the family Agavaceae. Also recycled
fibers which may contain any of the above fiber sources in different
percentages, can be used in the present invention. Suitable fibers are
disclosed in U.S. Patent Nos., 5,320,710 and 3,620,911 , both of which are incorporated herein by reference.
Papermaking fibers can be liberated from their source material by any one of the number of chemical pulping processes familiar to one experienced in the art including sulfate, sulfite, polysulfide, soda pulping, etc. The pulp can be bleached if desired by chemical means including the use of chlorine,
chlorine dioxide, oxygen, etc. Furthermore, papermaking fibers can be liberated from source material by any one of a number of
mechanical/chemical pulping processes familiar to anyone experienced in the art including mechanical pulping, thermomechanical pulping, and chemi-
thermomechanical pulping. These mechanical pulps can be bleached, if
necessary, by a number of familiar bleaching schemes including alkaline
peroxide and ozone bleaching.
The suspension of fibers or furnish may contain chemical additives to alter the physical properties of the paper produced. These chemistries are well understood by the skilled artisan and may be used in any known
combination.
The pulp can be mixed with strength adjusting agents such as wet
strength agents, dry strength agents and debonders/softeners. Suitable wet strength agents will be readily apparent to the skilled artisan. A
comprehensive but non-exhaustive list of useful wet strength aids include
urea-formaldehyde resins, melamine formaldehyde resins, glyoxylated polyacrylamide resins, polyamide-epichlorhydrin resins and the like.
Thermosetting polyacrylamides are produced by reacting acrylamide with
diallyl dimethyl ammonium chloride (DADMAC) to produce a cationic polyacrylamide copolymer which is ultimately reacted with glyoxal to produce a cationic cross-linking wet strength resin, glyoxylated polyacrylamide. These materials are generally described in U.S. Patent Nos. 3,556,932 to Coscia et
al. and 3,556,933 to Williams et al., both of which are incorporated herein by reference in their entirety. Resins of this type are commercially available under the tradename of PAREZ 631 NC by Cytec Industries. Different mole ratios of acrylamide/DADMAC/glyoxal can be used to produce cross-linking
resins, which are useful as wet strength agents. Furthermore, other
dialdehydes can be substituted for glyoxal to produce thermosetting wet
strength characteristics. Of particular utility are the polyamide-epichlorhydrin resins, an example of which is sold under the tradenames Kymene 557LX and Kymene 557H by Hercules Incorporated of Wilmington, Delaware and CASCAMID® from Borden Chemical Inc. These resins and the process for
making the resins are described in U.S. Patent No. 3,700,623 and U.S. Patent No. 3,772,076 each of which is incorporated herein by reference in its
entirety. An extensive description of polymeric-epihaiohydrin resins is given in
Chapter 2: Alkaline -Curing Polymeric Amine-Epichlorohvdrin by Espy in Wet
-Strength Resins and Their Application (L. Chan, Editor, 1994), herein
incorporated by reference in its entirety. A reasonably comprehensive list of wet strength resins is described by Westfelt in Cellulose Chemistry and Technology, Volume 13, p. 813, 1979, which is incorporated herein by
reference. The pulp, when making towel grades according to the present invention, preferably contains up to about 30 lbs/ton, more preferably from 10 to 20 lbs/ton of wet strength aids. Wet strength resins are not normally added
to tissue grades. Suitable dry strength agents will be readily apparent to one skilled in
the art. A comprehensive but non-exhaustive list of useful dry strength aids
includes starch, guar gum, polyacrylamides, carboxymethyl cellulose and the like. Of particular utility is carboxymethyl cellulose, an example of which is
sold under the tradename Hercules CMC by Hercules Incorporated of
Wilmington, Delaware. The pulp preferably contains from 0 to10 lbs/ton, more preferably from 1 to 5 lbs/ton of dry strength aid.
Suitable debonders will be readily apparent to the skilled artisan. Debonders or softeners may also be incorporated into the pulp or sprayed
upon the web after its formation. The pulp preferably contains from 0 to 10 lbs/ton, more preferably from 1 to 5 lbs/ton of debonder/softener.
The present invention may be used with a particular class of softener materials - amido amine salts derived from partially acid neutralized amines.
Such materials are disclosed in U.S. Patent No. 4,720,383. Evans, Chemistry and Industry, 5 July 1969, Pp. 893-903; Egan, J. Am. Oil Chemist's Soc. Vol. 55 (1978), Pp. 118-121 ; and Trivedi et al.. J. Am. Oil Chemist's Soc. June 1981 , Pp. 754-756, incorporated by reference in their entirety, indicate that
softeners are often available commercially only as complex mixtures rather
than as single compounds. While the following discussion will focus on the predominant species, it should be understood that commercially available mixtures would generally be used in practice.
Quasoft 202-JR is a suitable softener material, which may be derived by alkylating a condensation product of oleic acid and diethylenetriamine.
Synthesis conditions using a deficiency of alkylation agent (e.g., diethyl sulfate) and only one alkylating step, followed by pH adjustment to protonate
the non-ethylated species, result in a mixture consisting of cationic ethyiated and cationic non-ethylated species. A minor proportion (e.g., about 10%) of the resulting amido amine cyclize to imidazoline compounds. Since only the imidazoline portions of these material are quaternary ammonium compounds,
the compositions as a whole are pH-sensitive. Therefore, in the practice of the present invention with this class of chemicals, the pH in the headbox
should be approximately 6 to 8, more preferably 6 to 7 and most preferably
6.5 to 7.
Quaternary ammonium compounds, such as dialkyl dimethyl quaternary ammonium salts are also suitable particularly when the alkyl
groups contain from about 14 to 20 carbon atoms. These compounds have the advantage of being relatively insensitive to pH.
Biodegradable softeners can be utilized. Representative biodegradable cationic softeners/debonders are disclosed in U.S. Patent Nos.
5,312,522; 5,415,737; 5,262,007; 5,264,082; and 5,223,096, all of which are incorporated herein by reference in their entirety. These compounds are biodegradable diesters of quaternary ammonia compounds, quaternized amine-esters, and biodegradable vegetable oil based esters functional with quaternary ammonium chloride and diester dierucyldimethyl ammonium
chloride and are representative biodegradable softeners.
The fibrous web is then either deposited on an impression drying
fabric, in the case of the TAD process or on a dewatering felt for the CWP process. Any art recognized fabrics or felts could be used with the present
invention. For example, a non-exhaustive list of impression fabrics would include plain weave fabrics described in U.S. Patent No. 3,301 ,746; semitwill fabrics described in U.S. Patent Nos. 3,974,025 and 3,905,863; bilateraily- staggered-wicker-basket-cavity type fabrics described in U.S. Patent Nos.
4,239,065 and 4,191 ,609; sculptured/load bearing layer type fabrics described in U.S. Patent No. 5,429,686; photopolymer fabrics described in U.S. Patent Nos. 4,529,480, 4,637,859, 4,514,345, 4,528,339, 5,364,504,
5,334,289, 5,275,799, and 5,260,171 ; and fabrics containing diagonal
pockets described in U.S. Patent No. 5,456,293. The aforementioned patents are incorporated herein by reference, in their entirety. Any art-recognized-felt
can be used with the present invention. For example, felts can have double- layer base weaves, triple-layer base weaves, or laminated base weaves.
Preferred felts according to the present invention are those having the laminated base weave design. A wet-press-felt found particularly useful with the present invention is AMFIex 3 made by Appleton Mills Corporation. Non- exhaustive background art in the press felt area includes U.S. Patent Nos. 5,657,797; 5,368,696; 4,973,512; 5,023,132; 5,225,269; 5,182,164;
5,372,876; and 5,618,612 all-of-which are incorporated herein by reference in their entirety. After the web made by the conventional wet press process has reached a solids content of about 15 %, more preferably about 20 %, the
web/foraminous fabric sandwich is contacted with a pressing blanket engaged with a pressing unit, one embodiment in the art referred to as a shoe press.
In a similar web made by through air drying, the web/foraminous fabric sandwich is preferably contacted with the pressing blanket engaged with a pressing unit after the web has reached a solids content of at least about
20%, more preferably at least about 25%.
The pressing unit including a pressing blanket according to the present invention can have any art-recognized configuration. The nip can be created
between the pressing unit and a backing roll, in the case of a stand-alone pressing unit, or can be created between the pressing unit and a transfer cylinder. As used in the present invention, backing roil refers to a roll that contacts the web but does not remove the fibrous web from the carrier fabric or felt. Backing rolls for use according to the present invention may be
heated or cold. The backing roll can be made of hard rubber or metal. When
the rolls are heated with an induction heater the roll is preferably constructed or coated with high diffusivity material, such as copper, to aid in increasing
heat transfer.
As used in the present invention, transfer cylinder refers to a roll that
picks up the fibrous web thereby transferring the fibrous web from the foraminous carrier fabric upon which it had been carried. Typical transfer
cylinders according to the present invention can include a steel roll, a metal coated roll, a granite roll, a Yankee drying cylinder, and a gas fired drying cylinder. Transfer cylinders for use according to the present method may be heated or cold. When the transfer cylinder is heated with an induction heater the cylinder is preferably constructed or coated with high diffusivity material, such as copper, to aid in increasing heat transfer. One or more transfer
cylinders may be used in the process according to the present invention. Heat is preferably applied to the transfer cylinder and/or backing roll.
Heat can be applied by any art-known scheme including induction heating, oil heating and steam heating. Commercial available induction heaters can
generate very high energy-transfer rates. An induction heater induces electrical current to the conducting roll surface. Since the induced current can be quite large, this factor produces a substantial amount of resistive heating
in the conducting roll. Backing roll or transfer cylinder temperature can be anywhere from ambient to 700 ° F but are more preferably from 180 ° F to
500 ° F. Preferred heating schemes according to the present invention are induction heating and steam-heating. Increased temperature in the backing roll or transfer cylinder
decreases the viscosity of the water and makes the sheet more deformable hence improving water removal. Also, increased temperature and operating pressure bring the sheet into intimate contact with the transfer cylinder or backing roll, which improves heat transfer to the web. Furthermore, high steam pressure in the web within the nip can aid in rapidly displacing water
from the sheet to the felt.
The pressing unit including a pressing blanket according to the
present invention is preferably a shoe press. A shoe press includes a shoe element(s), which is pressed against the backing roll or transfer cylinder. The shoe element is loaded hydrodynamically against the backing roll or transfer
cylinder causing a nip to be formed. A pressing belt or blanket traverses the shoe press nip with the fibrous web in contact with the foraminous fabric. Pressing blankets can be smooth, or to enhance water removal at the press they can be grooved or blind drilled. Conventional pressing blanket designs contain a fabric coated with polyurethane where the fabric is used as reinforcement. Other pressing blanket designs use yarns embedded in the polyurethane to provide reinforcement. One preferred pressing blanket according to the present invention is a yarn reinforced blanket design under the tradename QualiFlex B, which is supplied by Voith Sulzer Corporation.
The shoe element length can be less than about 7 inches but is more preferably less than about 3 inches for the present invention. According to the present invention the shoe element will also be referred to as a hydraulic
engagement member. Shoe designs can be hydrodynamic, hydrodynamic
pocket, or hydrostatic. In the hydrodynamic shoe design, the oil lubricant forms a wedge at the ingoing side of the nip ultimately causing the formation of a thin oil film that protects the blanket and the shoe. The hydrodynamic pocket design incorporates a machined full width pocket in the shoe used for emptying the oil in the pressurized zone of the shoe. The final design is the hydrostatic design where oil is fed into the center region of the shoe. The preferred shoe design according to the present invention is hydrodynamic.
Shoe presses for use according to the present invention can be open
or closed. Early shoe press designs were the open belt configurations where an impermeable pressing blanket encircled a series of rollers similar to that of
a fabric or felt run. These open designs suffered from papermachine system contamination by oil. The oil loss was at one time, up to 20 liters per day on some systems. The open shoe design is also inferior to a closed design since it cannot be operated in the inverted mode. The closed shoe design alleviates the oil contamination issue and is therefore preferred for use in the
present invention.
According to one embodiment of the present invention, the peak pressure in the shoe press is preferably greater than about 2000 kN/m2, with a line load of preferably less than about 240 kN/m. In another embodiment of
the present invention, for conventionally made wide-Yankee-dryers the peak pressure is preferably greater than about 2000 kN/m2, while the line load is
preferably less than about 175 kN/m and more preferably less than about 100 kN/m. For the purposes of the present invention, kN/m is an abbreviation for
kilonewtons per meter and kN/m2 is an abbreviation for kilonewtons per
square meter.
The sheet can be creped from the transfer cylinder by any art- recognized methods using any art recognized creping aid. The maximum line load a current standard Yankee can sustain is on the order of 100kN/m. When a Yankee is used in conjunction with a suction pressure roll, the Yankee needs to be precisely crowned at the prevailing load to obtain a uniform nip. This procedure is necessary due to the inflexibility of
the suction pressure roll arrangement and also due to loading at only the ends of the suction pressure roll. For the case of a shoe press, loading
occurs at multiple points across the cross machine direction; individual shoe elements can be installed across the machine to give more precise cross machine direction pressing flexibility; and the shoe press is flexible and capable of conforming to the Yankee dryer surface. As a result, the precision to which the Yankee is ground for crowning will be less.
Figure 6 shows a schematic sketch of a typical pressure distribution curve for a suction pressure roll described by symmetrical mathematical functions like the sine and haversine curves. Since the nip pressure is
relieved when the nip diverges, rewet is exacerbated for the suction pressure
roll. Figure 7 shows a schematic sketch of a pressure distribution curve for a shoe press with a steep drop off where the felt is stripped from the sheet and
later from the pressing blanket. Such a steep drop-off in pressure reduces
the amount of rewet. Figure 8 shows a schematic sketch of a pressure distribution curve for a shoe press with a steeper drop off and where suction occurs in the felt at the point of simultaneous separation of the felt, sheet, and blanket when the nip pressure reaches about zero. The negative pressure in the felt, when the blanket and felt are stripped apart, is caused by capillary forces and should aid in holding water in the felt and should help further
dewater the web.
Previous shoe, belt or blanket, and felt designs in wide nip presses do not permit optimum separation of these members. For instance, present
designs allow for quick separation of the felt and blanket since the felt cannot "wrap" the unsupported blanket. But the drawback is that the felt stays in
contact with the sheet allowing capillary flow back into the sheet, i.e., rewet (see Figure 9). Figure 9 is a schematic sketch of a shoe press nip showing sheet, felt, and blanket. Point A in Figure 9 is the point of zero pressure on
the pressure distribution curve at the exit side of the nip.
Rewet is determined in the literature by plotting moisture ratio versus the reciprocal of the basis weight using the following equation:
Kp = K0 + R/W
where Kp is the moisture ratio of the paper after the wet press in grams of
water per gram of fiber; K0 is the moisture ratio of paper for 1/W = 0; W is the
basis weight in g/m2; and R is the magnitude of the rewet of paper in g/m2 and corresponds to the slope of the straight line used to fit moisture ratio versus
reciprocal basis weight data. The aforementioned equation was first
established by John Sweet. Data plotted according to the above equation is
frequently referred to in the literature as a Sweet plot. The original work can be found in Sweet, J.S., Pulp and Paper Mag. Can., 62, No. 7: T267 (1961 ) and a review article can be found in Heller, H., MacGregor, M., and Bliesner,
W., Paper Technology and Industry, p.154, June, 1975. Rewet is much more significant for lightweight tissue grades than heavy weight linerboard grades.
Rewet has been estimated to be from 5 to 50 g/m2 of water, depending on the
felt, furnish, etc. Rewet for a conventional shoe press can be determined from the above equation. The amount of rewet for the optimum shoe press is preferably less than about 50 % of the amount determined from Sweet's
theory using a conventional shoe press system. Rewet is preferably from 0 to
10 g/m2 of water, more preferably from 0 to 5 g/m2 of water.
According to another embodiment of the present invention, a pressing felt wraps the blanket and, therefore, pulls away quickly from the sheet reducing the time for possible rewetting. This design, as depicted in Figure 10, can be achieved by altering the take-away angle of the felt from the nip and tapering the exit side of the shoe. To aid in blanket deflection from the felt at the exit side of the shoe, the blanket diameter can be reduced; the blanket can be eccentrically arranged with respects to the press plane; or a roll (not shown in Figure 10) positioned against the blanket can deflect the belt
further.
Figure 11 shows another embodiment according to the present
invention. In Figure 11 , a schematic sketch of a shoe press showing a sheet, felt, and blanket is displayed. This shoe press utilizes a very steep pressure
drop at and following the exit of a nip curve of the press while simultaneously,
separating the felt from the blanket and from the sheet. In this manner, the negative pressure generated by surface tension forces as the felt and blanket separate are effective in reducing the flow of water back into the sheet as the felt and sheet are separated. The drawing shows a sharp drop off of the blanket near the shoe which in turn permits a quick separation of the felt from both the blanket and the sheet. The outgoing felt would be pulled at an angle
that equally bisected the Yankee and blanket surfaces. Then by adjusting the tension on the felt, the exact point of separation can be controlled to affect the
minimum in rewet. A felt drive roll located immediately following the shoe
press can control the tension level on the felt. The objective of this embodiment according to the present invention is to affect the transfer of the sheet from the felt at the same time that the negative pulse caused by the separation of the felt and blanket occurs. This design not only minimizes the
time the felt is in contact with the sheet; the added vacuum pulse will significantly reduce the amount of water that can flow, even over the short time. Point A in Figure 11 is the point of zero pressure on the pressure
distribution curve at the exit side of the nip. The nip pressure curve for the sheet/felt in Figure 11 would most likely approach that shown in Figure 8.
The web is preferably either adhered to the Yankee dryer by nip
transfer with a pressing unit including a pressing blanket or is after pressing adhered to the Yankee dryer. The web is dried by steam and hot air
impingement hoods. Any suitable art recognized adhesive might be used on the Yankee dryer. Preferred adhesives include poiyvinyl alcohol with suitable plasticizers, glyoxylated polyacrylamide with or without poiyvinyl alcohol, and polyamide epichlorohydrin resins such as Quacoat A-252 (QA252),
Betzcreplus 97 (Betz+97) and Calgon 675 B. Suitable adhesives are widely described in the patent literature. A comprehensive but non-exhaustive list
includes U.S. Patent Nos. 5,246,544; 4,304,625; 4,064,213; 3,926,716; 4,501 ,640; 4,528,316; 4,788,243; 4,883,564; 4,684,439; 5,326,434;
4,886,579; 5,374,334; 4,440,898; 5,382,323; 4,094,718; 5,025,046; and 5,281 ,307. Typical release agents can be used in accordance with the
present invention.
The final product may be calendered or uncalendered and is usually
reeled to await further converting processes. The products according to the present invention may be subjected to any art recognized converting operations, including embossing, printing, etc.
The following example is illustrative of the invention embodied herein.
EXAMPLE 1
A nascent web was formed on a Crescent-forming machine using a
blend of 50/50 long fiber/short fiber refined to 23° SR freeness. Chemicals like wet strength agents or dry strength agents were not added to the stock.
The basis weight of the sheet on the Yankee dryer was 8.5 lbs/3000 ft2. Two
pressing arrangements were used on the paper machine. In the first pressing
arrangement, the sheet was pressed onto a Yankee dryer with a suction
pressure roll. The vacuum in the suction roll was nominally 0.22 bar. In the second pressing arrangement, the suction pressure roll was replaced by a
Yankee shoe press. The sheet was conditioned before the shoe press with a suction turning roll having the same size and open area as the suction pressure roll. The suction turning roll vacuum was nominally equivalent to the level used during the suction pressure roll experiments. After sheet
conditioning, the web was pressed onto the Yankee with a shoe press. In order to obtain precise sheet solids data after the shoe press or the suction
pressure roll, the Yankee dryer was run cold. Blotters were used to collect
flatsheets for physical property determination. Two types of shoes were run:
a typical 120 mm shoe and a 50 mm shoe. Figure 3 shows the pressure
distribution of the shoes and the suction pressure roll. Figure 12 depicts a plot of sheet solids versus line loading. The typical 120 mm shoe shows no solids benefit versus the suction pressure roll at present operating iine load limits of current Yankee dryers (i.e., approximately, 87.5 kN/m), while the 50 mm pressure optimized shoe press shows an advantage of several
percentage points of solids. Furthermore, the strength and specific volume
properties of a web made with the 50 mm pressure optimized shoe press were equivalent to the strength and specific volume properties of a web made
by the suction pressure roll.
Figures 13-15 illustrate a method for maximizing water removal in a press nip in accordance with another embodiment of the present invention.
The present embodiment involves a conventional wet pressing (CWP)
process. For consistency, like numbers have been used to indicate the
corresponding portions of the apparatus depicted in Figures 13-15 with those of Figures 1-12. The description of the apparatus of Figures 1-12 thus applies equally to this embodiment, unless stated otherwise.
Referring to Figure 13, the present embodiment uses a shoe press, preferably a controlled crown roll with a flexible shell and a concave shoe
hydrodynamically loaded against one another. The present embodiment further includes a belt or blanket (100) having a void volume that enhances
sheet solids after the shoe press to further improve water removal in the press nip. Appropriate void volume can be achieved by a number of blanket configurations, including, but not limited to, those made by grooving, blind drilling and the like. The total void volume of the belt or blanket for use according to the present invention is preferably about 50 to about 3000 cm3/m2, more preferably about 100 to about 1000 cm3/m2, most preferably from about 200 to about 500 cm3/m3.
Blankets for use according to the present invention can include any art
recognized blanket having, or which can be modified to have, the required
void volume. For example, blankets disclosed by E.J. Justus and D. Cronin in Tappi,
August 1964, Vol. 47, No. 8, p. 493, which is incorporated herein by reference, include grooved belts that improve water removal in a press nip
where the groove width is about 0.01 to about 0.03 in., the land width is about 2 to about 20 times the groove width and the groove depth is about 2 to about
10 times the groove width.
For another example, blankets disclosed by Bo-Christer Aberg in Das
Papier No.6, 1996, which is incorporated herein by reference, include grooved belts that work at higher line loads and machine speeds than smooth belts. The belts have groove widths of about 0.5 to about 1 mm and a void volume of about 100 cc/m2 to about 500 cc/m2.
For yet another example, blankets disclosed by P. Slater and K. Fitzpatrick in the 84th Annual Meeting of the Technical Section, CPPA, January 1998, which is incorporated herein by reference, include grooved belts that provide a press dryness about 1 % to about 3% greater than the press dryness obtained with a similar smooth belt. The belts have groove widths of about 0.58 to about 0.79 mm and a void volume of about 200 cc/m2
to about 365 cc/m2. For still another example, blankets disclosed by D. Madden et al. in the
Tappi 1998 Engineering Conference, which is incorporated herein by
reference, include grooved belts that provide a press dryness about 1 % greater than the dryness obtained with a blind drilled belt. The grooved belt has an open area of about a 20.3% and a void volume of about 260 cc/m2,
and the blind drilled belt has an open area of about 21 % and a void volume of
about 380 cc/m2 void volume.
Referring to Figure 14, blind drilling involves drilling holes into a smooth blanket, as will be understood by one of skill in the art. Nip
compression between a blind drilled blanket and the felt causes a hydraulic pressure gradient between the holes in the blanket and the felt which
improves water flow and removal.
The blind drilled blanket preferably has a plurality of holes sequentially
arranged in the machine direction and a plurality of rows sequentially
arranged in the cross-machine direction to cause a hydraulic pressure gradient. The blind drilled blanket can take a variety of configurations. For
example, the hole depth, hole diameter, hole spacing, hole angle, hole geometry, row spacing and/or row pattern can be varied.
In particular, the hole depth can range from about 0.2 to about 10 mm, more preferably about 0.5 to about 5 mm, most preferably from about 0.5 to
about 3 mm. Also, the hole depth can extend partially or completely through
the blanket.
The hole diameter can range from about 0.2 to about 10 mm, more preferably about 0.5 to about 5 mm, most preferably from about 1 to about 3
mm.
The hole spacing can range from about 1 to about 20 mm between
holes arranged within the same row, more preferably about 1 to about 10 mm,
most preferably from about 1 to about 5 mm. The hole angle (i.e., the angle measured from the surface of the belt material counterclockwise to the side of the hole) can range from about 45 to about 135 degrees along any wall in either the machine or cross-machine, more preferably about 70 to about 110 degrees, most preferably from about
80 to about 100 degrees. The row spacing can range from about 1 to about 20 mm, more
preferably about 1 to about 10 mm, most preferably from about 1 to about 5
mm.
The hole geometry can be curved, linear or curvilinear, e.g. round,
square, elliptical, polygonal, and the row pattern can be such that the holes in each row are aligned in the cross-machine direction, offset in the cross- machine direction, aligned in the machine direction, offset in the machine
direction and the like.
There is no requirement that all holes have the same configuration,
rather, each of the holes can have a different configuration, or one or more individual or set of holes can have the same configuration as one or more
other individual or set of holes. Further, there is no requirement that the hole pattern form any type of geometric or other pattern, for example, the pattern can be random.
Referring to Figure 15, forming grooves in the blanket involves
removing elongated sections, as will be understood by one of skill in the art.
Nip compression of the grooved blanket and the press felt causes a hydraulic pressure gradient in the machine direction, which improves water flow and removal.
The grooved blanket preferably has a plurality of grooved sections sequentially arranged in the cross-machine direction that circumscribe the blanket to cause machine direction water movement. The grooved blanket can take a variety of configurations. For example, the groove depth, groove
width, groove bevel, groove angle, land width, open area and groove pattern
can all be varied.
In particular, the groove depth can range from about 0.1 to about 8 mm, more preferably about 0.2 to about 5 mm, most preferably from about
0.4 to about 3mm. The groove width can range from about 0.1 to about 6 mm, more preferably about 0.2 to about 4 mm, most preferably from about 0.4 to about 3
mm.
The groove bevel (i.e., the angle measured from the surface of the belt material counterclockwise to the side of the groove minus 90°) can range from about 0 to about 45°, more preferably about 0 to about 30°, most preferably from about 0 to about 20°.
The groove angle can range from about 45 to about 135 degrees (with 90 degrees being orthogonal to the cross-machine direction), more preferably
about 65 to about 115°, most preferably from about 80 to about 100°. The land width can range from about 0.2 to about 25 mm, more
preferably about 0.4 to about 10 mm, most preferably from about 0.6 to about 4 mm. The open area can range up to 80% of the total blanket area, more preferably about 15 to about 50%, most preferably from about 20 to about
40%.
The groove pattern can be such that the grooves in each row are
aligned in the cross-machine direction, offset in the cross-machine direction, aligned in the machine direction, offset in the machine direction and the like.
Also, for blankets for use in the present invention, grooves need not have the same configuration, rather, all the grooves can have a different configuration,
or one or more individual or set of grooves can have the same configuration as one or more other individual or set of grooves. Further, there is no
requirement that the groove pattern form any type of geometric or other pattern, for example, the groove placement can also be random.
Blankets having the disclosed void volume will be readily apparent to the skilled artisan. Such blankets can include any physical arrangement as long as the void space requirements are satisfied. Blankets for use in the
present invention may be manufactured by any art recognized process, including but not limited to, casting molding, laser engraving, etc.
EXAMPLE 2 A punch press was used to perform dewatering experiments with different belt structures. An AMFIex 3S felt manufactured by Appleton Mills Corporation was used to dewater the paper web. The web basis weight was
8.9 Ibs/rm. The felt dryness was controlled to 69.3% dryness by using blotters
and a couch roll to remove excess water. Web moisture was controlled to 19.3% dryness by rewetting moist webs using a water spray. The webs were
made from a 50/50 blend of northern softwood kraft and eucalyptus refined in a PFI mill to 510 ml CSF.
A smooth belt, a blind drilled belt and a grooved belt were used in the
punch press experiment. The blind drilled belt had a bore area of 3.82 mm2,
a bore depth of 1.76 mm, an open area of 22.73% and a void volume of 402.9 cc/m2. The grooved belt had a groove width of 0.66 mm, a groove depth of
1.41 mm, a pitch of 0.33 grooves/mm, an open area of 21.78%, and a void volume of 270.6 cc/m2.
The punch press was operated such that the average nip pressure was
fixed at 400 psi and the average nip dwell time was fixed at 1.8 ms. The experimental post press dryness results for the experiment were: smooth belt 31.0 +/- 0.30% blind drilled belt 39.2 +/- 0.28%
grooved belt 40.3 +/- 0.42% with the +/- percentage being the 95% confidence limit for the test.
These results indicate that pressing with either a blind drilled or grooved belt leads to enhanced sheet solids when compared to a smooth belt. These results also indicate that pressing with a grooved belt leads to enhanced sheet solids over a blind drilled belt.
Other embodiments of the invention will be apparent to those skilled in
the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention
being indicated by the following claims.

Claims

We Claim:
1. An apparatus for forming an absorbent paper sheet product comprising: a moving foraminous endless fabric; means for depositing a nascent web for said absorbent paper sheet on said foraminous endless fabric; a moving endless pressing blanket;
a Yankee drying cylinder; and a pressing unit engaging said pressing blanket adapted to urge said
nascent web for said absorbent paper sheet on said foraminous endless
fabric into engagement with said Yankee drying cylinder thereby forming a
nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than
about 240 kN/m.
2. The apparatus of claim 1 , wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such that the pressure declines from a peak pressure to a value of 20% of said peak pressure over a nip length which is no more than about half of the nip length over which it rose to said peak pressure from 20% of said peak
pressure.
3. The apparatus of claim 1 , wherein said pressing unit comprises at least one hydraulic engagement member.
4. The apparatus of claim 3, wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
5. The apparatus of claim 4, wherein said at least one hydraulic engagement member has a length of less than about 2 inches.
6. The apparatus of claim 1 , wherein said foraminous endless fabric is a press felt or an impression fabric
7. The apparatus of claim 1 , wherein the means for forming a nascent web is selected from a crescent former, a twin wire former, a suction
breast roll former, or a fourdrinier former.
8. The apparatus of claim 1 , wherein said pressing unit is configured to have a line load of less than about 175 kN/m.
9. The apparatus of claim 1 , wherein said pressing unit is configured to have a line load of less than about 100 kN/m.
10. The apparatus of claim 1 , wherein the peak pressure in said nip is at least about 2500 kN/m2.
11. The apparatus of claim 1 , wherein the peak pressure in said nip is at least about 3000 kN/m2.
12. The apparatus of claim 1 , wherein the peak pressure in said nip is at least about 3150 kN/m2.
13. The apparatus of claim 1 , further comprising a creping blade for removing said absorbent paper sheet from said Yankee dryer.
14. The apparatus of claim 1 , wherein said pressing unit is configured to disengage said web from said foraminous endless fabric such that rewet of said nascent web by said foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the
properties of said foraminous endless fabric and said nascent web.
15. The apparatus of claim 14, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric at a nip length of less than about one inch from the point the nip pressure reaches
zero.
16. The apparatus of claim 14, wherein said pressing unit is
configured to both disengage said web from said foraminous endless fabric and disengage said foraminous endless fabric from said pressing blanket at a
nip length of less than about one inch from the point the nip pressure reaches
zero.
17. An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric; means for depositing a nascent web for said absorbent paper sheet on
said foraminous endless fabric; a moving endless pressing blanket;
a Yankee drying cylinder; and
a pressing unit engaging said pressing blanket adapted to urge said nascent web for said absorbent paper sheet on said foraminous endless
fabric into engagement with said Yankee drying cylinder thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall iine load of less than about 240 kN/m, said pressing unit being configured to disengage said web from said foraminous endless fabric such that rewet of said nascent web by said
foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the properties of said foraminous endless fabric and said nascent web.
18. The apparatus of claim 17, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric at a
nip length of less than about one inch from the point the nip pressure reaches
zero.
19. The apparatus of claim 17, wherein said pressing unit is
configured to both disengage said web from said foraminous endless fabric and disengage said foraminous endless fabric from said pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches
zero.
20. The apparatus of claim 17, wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon
said nascent web, said asymmetrical pressure distribution being skewed such that the pressure declines from a peak pressure to a value of 20% of said peak pressure over a nip length which is no more than about half of the nip
length over which it rose to said peak pressure from 20% of said peak
pressure.
21. The apparatus of claim 17, wherein said pressing unit comprises at least one hydraulic engagement member.
22. The apparatus of claim 21 , wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
23. The apparatus of claim 22, wherein said at least one hydraulic engagement member has a length of less than about 2 inches.
24. The apparatus of claim 17, wherein said foraminous endless
fabric is a press felt or an impression fabric.
25. The apparatus of claim 17, wherein the means for forming a
nascent web is selected from a crescent former, a twin wire former, a suction breast roll former, or a fourdrinier former.
26. The apparatus of claim 17, wherein said pressing unit is
configured to have a line load of less than about 175 kN/m.
27. The apparatus of claim 17, wherein said pressing unit is configured to have a line load of less than about 100 kN/m.
28. The apparatus of claim 17, wherein the peak pressure in said
nip is at least about 2500 kN/m2.
29. The apparatus of claim 17, wherein the peak pressure in said
nip is at least about 3000 kN/m2.
30. The apparatus of claim 17, wherein the peak pressure in said nip is at least about 3150 kN/m2.
31. The apparatus of claim 17, further comprising a creping blade for removing said absorbent paper sheet from said Yankee dryer.
32. An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric; means for depositing a nascent web for said absorbent paper sheet on said foraminous endless fabric; a moving endless pressing blanket;
a Yankee drying cylinder; and
a pressing unit engaging said pressing blanket adapted to urge said
nascent web for said absorbent paper sheet on said foraminous endless
fabric into engagement with said Yankee drying cylinder thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than
about 240 kN/m, said pressing unit being configured to both disengage said web from said foraminous endless fabric and disengage said foraminous endless fabric from said pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches zero.
33. The apparatus of claim 32, wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such that the pressure declines from a peak pressure to a value of 20% of said
peak pressure over a nip length which is no more than about half of the nip length over which it rose to said peak pressure from 20% of said peak pressure.
34. The apparatus of claim 32, wherein said pressing unit comprises at least one hydraulic engagement member.
35. The apparatus of claim 34, wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
36. The apparatus of claim 35, wherein said at least one hydraulic engagement member has a length of less than about 2 inches.
37. The apparatus of claim 32, wherein said foraminous endless fabric is a press felt or an impression fabric.
38. The apparatus of claim 32, wherein the means for forming a
nascent web is selected from a crescent former, a twin wire former, a suction breast roll former, or a fourdrinier former.
39. The apparatus of claim 32, wherein said pressing unit is configured to have a line load of less than about 175 kN/m.
40. The apparatus of claim 32, wherein said pressing unit is configured to have a line load of less than about 100 kN/m.
41. The apparatus of claim 32, wherein the peak pressure in said nip is at least about 2500 kN/m2.
42. The apparatus of claim 32, wherein the peak pressure in said nip is at least about 3000 kN/m2.
43. The apparatus of claim 32, wherein the peak pressure in said nip is at least about 3150 kN/m2.
44. The apparatus of claim 32, further comprising a creping blade for removing said absorbent paper sheet from said Yankee dryer.
45. The apparatus of claim 32, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric such that rewet of said nascent web by said foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the
properties of said foraminous endless fabric and said nascent web.
46. An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric;
means for depositing a nascent web for said absorbent paper sheet on
said foraminous endless fabric; a moving endless pressing blanket;
a transfer cylinder; and a pressing unit engaging said pressing blanket adapted to urge said nascent web for said absorbent paper sheet on said foraminous endless fabric into engagement with said transfer cylinder thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at
least about 2000 kN/m2 at an overall line load of less than about 240 kN/m.
47. The apparatus of claim 46, wherein said pressing unit is additionally configured to impose an asymmetrical pressure distribution upon
said nascent web, said asymmetrical pressure distribution being skewed such
that the pressure declines from a peak pressure to a value of 20% of said peak pressure over a nip length which is no more than about half of the nip length over which it rose to said peak pressure from 20% of said peak pressure.
48. The apparatus of claim 46, wherein said pressing unit comprises at least one hydraulic engagement member.
49. The apparatus of claim 48, wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
50. The apparatus of claim 49, wherein said at least one hydraulic
engagement member has a length of less than about 2 inches.
51. The apparatus of claim 46, wherein said foraminous endless fabric is a press felt or an impression fabric.
52. The apparatus of claim 46, wherein the means for forming a nascent web is selected from a crescent former, a twin wire former, a suction breast roll former, or a fourdrinier former.
53. The apparatus of claim 46, wherein said pressing unit is configured to have a line load of less than about 175 kN/m.
54. The apparatus of claim 46, wherein said pressing unit is configured to have a line load of less than about 100 kN/m.
55. The apparatus of claim 46, wherein the peak pressure in said nip is at least about 2500 kN/m2.
56. The apparatus of claim 46, wherein the peak pressure in said nip is at least about 3000 kN/m2.
57. The apparatus of claim 46, wherein the peak pressure in said nip is at least about 3150 kN/m2.
58. The apparatus of claim 46, further comprising a creping blade for removing said absorbent paper sheet from said transfer cylinder.
59. The apparatus of claim 46, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric such
that rewet of said nascent web by said foraminous endless fabric is less than
about 50% of the rewet predicted by the Sweet equations based upon the properties of said foraminous endless fabric and said nascent web.
60. The apparatus of claim 59, wherein said pressing unit is
configured to disengage said web from said foraminous endless fabric at a
nip length of less than about one inch from the point the nip pressure reaches
zero.
61. The apparatus of claim 59, wherein said pressing unit is configured to both disengage said web from said foraminous endless fabric and disengage said foraminous endless fabric from said pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches
zero.
62. The apparatus of claim 46, wherein said transfer cylinder is
heated.
63. The apparatus of claim 46, wherein said transfer cylinder is
selected from a granite roll, a cold steel roll, a gas fired heater, or a Yankee
drying cylinder.
64. The apparatus of claim 63, wherein said transfer cylinder is a Yankee drying cylinder.
65. The apparatus of claim 64, further comprising a creping blade for removing said absorbent paper sheet from said Yankee drying cylinder.
66. The apparatus of claim 62, wherein said transfer cylinder is heated by an induction heater.
67. An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric;
means for depositing a nascent web for said absorbent paper sheet on
said foraminous endless fabric; a moving endless pressing blanket;
a transfer cylinder; and a pressing unit engaging said pressing blanket adapted to urge said nascent web for said absorbent paper sheet on said foraminous endless fabric into engagement with said transfer cylinder thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at
least about 2000 kN/m2.
68. The apparatus of claim 67, wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such
that the pressure declines from a peak pressure to a value of 20% of said
peak pressure over a nip length which is no more than about half of the nip length over which it rose to said peak pressure from 20% of the said peak pressure.
69. The apparatus of claim 67, wherein said pressing unit comprises at least one hydraulic engagement member.
70. The apparatus of claim 69, wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
71. The apparatus of claim 70, wherein said at least one hydraulic
engagement member has a length of less than about 2 inches.
72. The apparatus of claim 67, wherein said foraminous endless fabric is a press felt or an impression fabric.
73. The apparatus of claim 67, wherein the means for forming a nascent web is selected from a crescent former, a twin wire former, a suction
breast roll former, or a fourdrinier former.
74. The apparatus of claim 67, wherein said pressing unit is configured to have a line load of less than about 240 kN/m.
75. The apparatus of claim 67, wherein said pressing unit is configured to have a line load of less than about 175 kN/m.
76. The apparatus of claim 67, wherein said pressing unit is configured to have a line load of less than about 100 kN/m.
77. The apparatus of claim 67, wherein the peak pressure in said
nip is at least about 2500 kN/m2.
78. The apparatus of claim 67, wherein the peak pressure in said nip is at least about 3000 kN/m2.
79. The apparatus of claim 67, wherein the peak pressure in said nip is at least about 3150 kN/m2.
80. The apparatus of claim 67, wherein said transfer cylinder is heated.
81. The apparatus of claim 67, wherein said transfer cylinder is selected from a granite roll, a cold steel roll, a gas fired heater or a Yankee drying cylinder.
82. The apparatus of claim 81 , wherein said transfer cylinder is a Yankee drying cylinder.
83. The apparatus of claim 82, further comprising a creping blade for removing said absorbent paper sheet from said Yankee drying cylinder.
84. The apparatus of claim 67, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric such that rewet of said nascent web by said foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the properties of said foraminous endless fabric and said nascent web.
85. The apparatus of claim 67, further comprising a creping blade for removing said absorbent paper sheet from said transfer cylinder.
86. The apparatus of claim 80, wherein said transfer cylinder is heated by an induction heater.
87. The apparatus of claim 84, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric at a nip length of less than about one inch from the point the nip pressure reaches
zero.
88. The apparatus of claim 84, wherein said pressing unit is configured to both disengage said web from said foraminous endless fabric
and disengage said foraminous endless fabric from said pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches
zero.
89. An apparatus for forming an absorbent paper sheet product comprising: a moving foraminous endless fabric; means for depositing a nascent web for said absorbent paper sheet on said foraminous endless fabric; a moving endless pressing blanket;
a backing roll; and
a pressing unit engaging said pressing blanket adapted to urge said nascent web for said absorbent paper sheet on said foraminous endless
fabric into engagement with said backing roll thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at
least about 2000 kN/m2 at an overall line load of less than about 240 kN/m.
90. The apparatus of claim 89, wherein said pressing unit is additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such that the pressure declines from a peak pressure to a value of 20% of said peak pressure over a nip length which is no more than about half of the nip
length over which it rose to said peak pressure from 20% of said peak
pressure.
91. The apparatus of claim 89, wherein said pressing unit comprises
at least one hydraulic engagement member.
92. The apparatus of claim 91 , wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
93. The apparatus of claim 92, wherein said at least one hydraulic engagement member has a length of less than about 2 inches.
94. The apparatus of claim 89, wherein said foraminous endless fabric is a press felt or an impression fabric.
95. The apparatus of claim 89, wherein the means for forming a nascent web is selected from a crescent former, a twin wire former, a suction
breast roll former, or a fourdrinier former.
96. The apparatus of claim 89, wherein said backing roll is heated.
97. The apparatus of claim 96, wherein said backing roll is heated
by steam.
98. The apparatus of claim 96, wherein said baking roll is heated by an induction heater.
99. The apparatus of claim 89, wherein said pressing unit is configured to have a line load of less than about 175 kN/m.
100. The apparatus of claim 89, wherein said pressing unit is configured to have a line load of less than about 100 kN/m.
101. The apparatus of claim 89, wherein the peak pressure in said nip is at least about 2500 kN/m2.
102. The apparatus of claim 89, wherein the peak pressure in said nip is at least about 3000 kN/m2.
103. The apparatus of claim 89, wherein the peak pressure in said
nip is at least about 3150 kN/m2.
104. A method of making an absorbent paper sheet product
comprising: depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric; and contacting said moving foraminous endless fabric bearing said deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m.
105. The method of claim 104, wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such
that the pressure declines from a peak pressure to a value of 20% of said peak pressure over a nip length which is no more than about half of the nip
length over which it rose to said peak pressure from 20% of said peak
pressure.
106. The method of claim 104, wherein said pressing unit comprises at least one hydraulic engagement member.
107. The method of claim 106, wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
108. The method of claim 107, wherein said at least one hydraulic engagement member has a length of less than about 2 inches.
109. The method of claim 104, wherein said foraminous endless
fabric is a press felt or an impression fabric.
110. The method of claim 104, wherein said pressing unit is configured to have a line load of less than about 175 kN/m.
111. The method of claim 104, wherein said pressing unit is
configured to have a line load of less than about 100 kN/m.
112. The method of claim 104, wherein the peak pressure in said nip is at least about 2500 kN/m2.
113. The method of claim 104, wherein the peak pressure in said nip
is at least about 3000 kN/m2.
114. The method of claim 104, wherein the peak pressure in said nip
is at least about 3150 kN/m2.
115. The method of claim 104, wherein said pressing unit is
configured to disengage said web from said foraminous endless fabric such that rewet of said nascent web by said foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the properties of said foraminous endless fabric and said nascent web.
116. The method of claim 115, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric at a nip length of less than about one inch from the point the nip pressure reaches
zero.
117. The method of claim 115, wherein said pressing unit is
configured to both disengage said web from said foraminous endless fabric
and disengage said foraminous endless fabric from said pressing blanket at a
nip length of less than about one inch from the point the nip pressure reaches
zero.
118. The method of claim 104, wherein said nascent web contacts a transfer cylinder.
119. The method of claim 118, wherein said transfer cylinder is heated.
120. The method of claim 104, wherein said nascent web contacts a
backing roll.
121. The method of claim 120, wherein said backing roll is heated.
122. The method of claim 119, wherein said transfer cylinder is heated by an induction heater.
123. The method of claim 121 , wherein said backing roll is heated by
an induction heater.
124. The method of claim 118, further comprising a creping blade for removing said absorbent sheet from said transfer cylinder.
125. The method of claim 104, wherein said moving endless blanket engaged with said pressing unit forms said nip with a Yankee drying cylinder.
126. The method of claim 125, wherein said web is dried on said
Yankee drying cylinder.
127. The method of claim 126, wherein said dried web is creped from
said Yankee drying cylinder.
128. The method of claim 104, wherein said pressing unit is a shoe
press.
129. The method of claim 121 , wherein said nascent web contacts
said backing roll.
130. The method of claim 104, wherein said nascent web is compactively dewatered on said foraminous endless fabric prior to entering
said nip.
131. The method of 104, wherein said pressing unit includes a hydraulic engagement member and said hydraulic engagement member is
shaped and positioned to substantially align the separation of said foraminous endless fabric from said web and the separation of said foraminous endless
fabric from said endless pressing blanket.
132. A method of making an absorbent paper sheet product
comprising: depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric;
contacting said moving foraminous endless fabric bearing said deposited nascent web with a moving endless pressing blanket engaged with a pressing unit thereby forming a nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than about 240 kN/m;
transferring said web to a Yankee drying cylinder; and
creping said web from said Yankee drying cylinder.
133. The method of claim 132, wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon
said nascent web, said asymmetrical pressure distribution being skewed such that the pressure declines from a peak pressure to a value of 20% of said peak pressure over a nip length which is no more than about half of the nip length over which it rose to said peak pressure from 20% of said peak
pressure.
134. The method of claim 132, wherein said moving endless pressing blanket
engaged with said pressing unit is configured to form said nip with said Yankee drying cylinder.
135. The method of claim 132, wherein said moving endless pressing blanket engaged with said pressing unit is configured to form said nip with a
backing roll.
136. The method of claim 132, wherein said nascent web is compactively dewatered on said foraminous endless fabric prior to entering said nip.
137. The method of claim 132, wherein said pressing unit includes a hydraulic engagement member and said hydraulic engagement member is shaped and positioned to substantially align the separation of said foraminous
endless fabric from said web and the separation of said foraminous endless fabric from said endless pressing blanket.
138. The method of claim 132, wherein said pressing unit is
configured to both disengage said web from said foraminous endless fabric
and disengage said foraminous endless fabric from said pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches
zero.
139. The method of claim 132, wherein said pressing unit is configured to have a line load of less than about 175 kN/m.
140. The method of claim 132, wherein said pressing unit is
configured to have a line load of less than about 100 kN/m.
141. The method of claim 132, wherein said pressing unit comprises at least one hydraulic engagement member.
142. The method of claim 141 , wherein said at least one hydraulic
engagement member has a length of less than about 3 inches.
143. The method of claim 142, wherein said at least one hydraulic engagement member has a length of less than about 2 inches.
144. The method of claim 132, wherein the peak pressure in said nip is at least about 2500 kN/m2.
145. The method of claim 132, wherein the peak pressure in said nip is at least about 3000 kN/m2.
146. The method of claim 132, wherein the peak pressure in said nip is at least about 3150 kN/m2.
147. A method of making an absorbent paper sheet product
comprising: depositing a nascent web for said absorbent paper sheet product on a
moving foraminous endless fabric; contacting said moving foraminous endless fabric bearing said deposited nascent web with a shoe press thereby forming a nip between said shoe press and a Yankee drying cylinder, said shoe press being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an
overall line load of less than about 240 kN/m; disengaging said web from said foraminous endless fabric in said nip
onto said Yankee drying cylinder; and drying said web on said Yankee drying cylinder; and
creping said web from said Yankee drying cylinder.
148. The method of claim 147, wherein said shoe press is configured to have a line load of less than about 175 kN/m.
149. The method of claim 147, wherein said shoe press is configured to have a line load of less than about 100 kN/m.
150. The method of claim 147, wherein said shoe press comprises at least one hydraulic engagement member.
151. The method of claim 150, wherein said at least one hydraulic engagement member has a length of less than about 3 inches.
152. The method of claim 151 , wherein said at least one hydraulic engagement member has a length of less than about 2 inches.
153. The method of claim 147, wherein the peak pressure in said nip
is at least about 2500 kN/m2.
154. The method of claim 147, wherein the peak pressure in said nip is at least about 3000 kN/m2.
155. The method of claim 147, wherein the peak pressure in said nip is at least about 3150 kN/m2.
156. The method of claim 147, wherein said shoe press is additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such that the pressure declines from a peak pressure to a value of 20% of said
peak pressure over a nip length which is no more than about half of the nip length over which it rose to said peak pressure from 20% of said peak
pressure.
157. An apparatus for forming an absorbent paper sheet product
comprising: a moving foraminous endless fabric;
means for depositing a nascent web for said absorbent paper sheet on said foraminous endless fabric; a moving endless pressing blanket having a void volume; a Yankee drying cylinder; and a pressing unit engaging said pressing blanket adapted to urge said nascent web for said absorbent paper sheet on said foraminous endless
fabric into engagement with said Yankee drying cylinder thereby forming a
nip, said pressing unit being configured to create a peak engagement
pressure of at least about 2000 kN/m2 at an overall line load of less than
about 240 kN/m.
158. The apparatus of claim 157, wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such that the pressure declines from a peak pressure to a value of 20% of said peak pressure over a nip length which is no more than about half of the nip
length over which it rose to said peak pressure from 20% of said peak
pressure.
159. The apparatus of claim 157, wherein said foraminous endless
fabric is a press felt or an impression fabric.
160. The apparatus of claim 157, wherein the means for forming a
nascent web is selected from a crescent former, a twin wire former, a suction breast roll former, or a fourdrinier former.
161. The apparatus of claim 157, further comprising a creping blade for removing said absorbent paper sheet from said Yankee dryer.
162. The apparatus of claim 157, wherein said pressing unit is
configured to disengage said web from said foraminous endless fabric such
that rewet of said nascent web by said foraminous endless fabric is less than
about 50% of the rewet predicted by the Sweet equations based upon the properties of said foraminous endless fabric and said nascent web.
163. The apparatus of claim 162, wherein said pressing unit is
configured to disengage said web from said foraminous endless fabric at a nip length of less than about one inch from the point the nip pressure reaches
zero.
164. The apparatus of claim 163, wherein said pressing unit is
configured to both disengage said web from said foraminous endless fabric and disengage said foraminous endless fabric from said pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches
zero.
165. The apparatus of claim 157, wherein the pressing blanket is a
blind drilled blanket.
166. The apparatus of claim 165, wherein the blind drilled blanket
has a plurality of holes formed thereon.
167. The apparatus of claim 166, wherein the holes are sequentially
arranged in the machine direction.
168. The apparatus of claim 166, wherein the diameter of the holes is about 0.2 to about 10 mm.
169. The apparatus of claim 166, wherein the holes extend into but not through the blanket.
170. The apparatus of claim 166, wherein the angle of the holes as
measured along a hole wall vertically extending in the machine direction
ranges from about 45 to about 135 degrees.
171. The apparatus of claim 166, wherein the angle of the holes as
measured along a hole wall vertically extending in the cross-machine direction can range from about 45 to about 135 degrees.
172. The apparatus of claim 166, wherein the spacing between adjacent holes is about 1 to about 20 mm.
173. The apparatus of claim 167, wherein a plurality of rows of holes are sequentially arranged in the cross-machine direction.
174. The apparatus of claim 173, wherein the spacing between rows
is about 1 to about 20 mm.
175. The apparatus of claim 173, wherein the rows of holes are
arranged in a geometric pattern.
176. The apparatus of claim 175, wherein the geometric pattern is arranged so that the holes in each row are aligned in the cross-machine
direction.
177. The apparatus of claim 175, wherein the geometric pattern is arranged so that the holes in each row are offset in the crass-machine direction.
178. The apparatus of claim 175, wherein the geometric pattern is arranged so that the holes in each row are aligned in the machine direction.
179. The apparatus of claim 175, wherein the geometric pattern is
arranged so that the holes in each row are offset in the machine direction.
180. The apparatus of claim 173, wherein or one or more individual hole or row of holes has the same configuration as one or more other
individual hole or row of holes.
181. The apparatus of claim 157, wherein the blanket is a grooved
blanket.
182. The apparatus of claim 181 , wherein the grooved blanket has at least one groove that extends in the machine direction.
183. The apparatus of claim 182, wherein the width of the widest
portion of a groove is about 0.1 to about 6 mm.
184. The apparatus of claim 182, wherein the groove extends into but not through the blanket and has a depth of about 0.1 to about 8 mm.
185. The apparatus of claim 182, wherein the groove bevel is about 0
to about 45 degrees.
186. The apparatus of claim 182, wherein the groove angle is about 45 to about 135 degrees, with 90 degrees being orthogonal to the cross-
machine direction.
187. The apparatus of claim 182, wherein a plurality of grooves are sequentially arranged in the cross-machine direction of the blanket.
188. The apparatus of claim 187, wherein each of the plurality of grooves circumscribe the blanket.
189. The apparatus of claim 187, wherein the groove width is about 0.4 to about 3 mm.
190. The apparatus of claim 187, wherein the rows of grooves are
arranged in a geometric pattern.
191. The apparatus of claim 187, wherein one or more individual groove has the same configuration as one or more other individual groove.
192. The apparatus of claim 187, wherein the land width is about 0.2 to about 25 mm.
193. The apparatus of claim 187, wherein the open area is up to
about 80% of the total blanket area.
194. A moving endless pressing blanket for forming an absorbent paper sheet product produced by a pressing unit engaging said pressing
blanket adapted to urge a nascent web on a foraminous endless fabric into
engagement with a Yankee drying cylinder, said pressing unit being
configured to create a peak engagement pressure of at least about 2000
kN/m2 at an overall line load of less than about 240 kN/m, said pressing blanket comprising a void volume less than about 1500 cm3/m2.
195. The apparatus of claim 194, wherein the void volume is achieved by a blind drilled blanket.
196. The apparatus of claim 195, wherein the blind drilled blanket has a plurality of holes arranged in a predetermined geometric pattern.
197. The apparatus of claim 194, wherein the void volume is
achieved by a grooved blanket.
198. The apparatus of claim 197, wherein the grooved blanket has a
plurality of grooves arranged in a predetermined geometric pattern.
199. A method of making an absorbent paper sheet product
comprising: depositing a nascent web for said absorbent paper sheet product on a moving foraminous endless fabric; and contacting said moving foraminous endless fabric bearing said
deposited nascent web with a moving endless pressing void volume containing a pressing blanket engaged with a pressing unit thereby forming a
nip, said pressing unit being configured to create a peak engagement pressure of at least about 2000 kN/m2 at an overall line load of less than
about 240 kN/m.
200. The method of claim 199, wherein said pressing unit is
additionally configured to impose an asymmetrical pressure distribution upon said nascent web, said asymmetrical pressure distribution being skewed such
that the pressure declines from a peak pressure to a value of 20% of said
peak pressure over a nip length which is no more than about half of the nip length over which it rose to said peak pressure from 20% of said peak pressure.
201. The method of claim 199, wherein said pressing unit is configured to disengage said web from said foraminous endless fabric such that rewet of said nascent web by said foraminous endless fabric is less than about 50% of the rewet predicted by the Sweet equations based upon the
properties of said foraminous endless fabric and said nascent web.
202. The method of claim 201 , wherein said pressing unit is configured to disengage said web from said foraminous endless fabric at a
nip length of less than about one inch from the point the nip pressure reaches
zero.
203. The method of claim 201 , wherein said pressing unit is
configured to both disengage said web from said foraminous endless fabric and disengage said foraminous endless fabric from said pressing blanket at a nip length of less than about one inch from the point the nip pressure reaches
zero.
204. The method of claim 199, wherein said nascent web contacts a
heated transfer cylinder.
205. The method of claim 204, further comprising a creping blade for removing said absorbent sheet from said heated transfer cylinder.
206. The method of claim 199, wherein said moving void volume
containing endless blanket engaged with said pressing unit forms said nip
with a Yankee drying cylinder.
207. The method of claim 199, wherein said pressing unit is a shoe press.
PCT/US1999/027097 1998-11-13 1999-11-12 Method for maximizing water removal in a press nip WO2000029667A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP99960375A EP1047830A1 (en) 1998-11-13 1999-11-12 Method for maximizing water removal in a press nip
CA002317438A CA2317438C (en) 1998-11-13 1999-11-12 Method for maximizing water removal in a press nip
US10/376,319 US7300552B2 (en) 1998-11-13 2003-03-03 Method for maximizing water removal in a press nip
US11/874,251 US7754049B2 (en) 1998-11-13 2007-10-18 Method for maximizing water removal in a press nip

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US09/191,376 US6248210B1 (en) 1998-11-13 1998-11-13 Method for maximizing water removal in a press nip
US09/191,376 1998-11-13

Related Child Applications (2)

Application Number Title Priority Date Filing Date
US09/191,376 Continuation-In-Part US6248210B1 (en) 1998-11-13 1998-11-13 Method for maximizing water removal in a press nip
US09/439,610 Continuation-In-Part US6387217B1 (en) 1998-11-13 1999-11-12 Apparatus for maximizing water removal in a press nip

Publications (2)

Publication Number Publication Date
WO2000029667A1 true WO2000029667A1 (en) 2000-05-25
WO2000029667A9 WO2000029667A9 (en) 2000-11-02

Family

ID=22705241

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1999/027097 WO2000029667A1 (en) 1998-11-13 1999-11-12 Method for maximizing water removal in a press nip

Country Status (5)

Country Link
US (7) US6248210B1 (en)
EP (1) EP1047830A1 (en)
CA (1) CA2317438C (en)
TR (1) TR200002032T1 (en)
WO (1) WO2000029667A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1111127A3 (en) * 1999-12-23 2002-01-23 Voith Paper Patent GmbH Pressing arrangement
DE10233920A1 (en) * 2002-07-25 2004-02-12 Voith Paper Patent Gmbh Papermaking machine dewaters tissue paper or web of fibrous hygiene web material in conjunction with a dewatering belt with reversible water take-up
DE10237826A1 (en) * 2002-08-19 2004-03-11 Voith Paper Patent Gmbh Device for the production of material webs
US6860968B1 (en) 2000-05-24 2005-03-01 Kimberly-Clark Worldwide, Inc. Tissue impulse drying
US7754049B2 (en) * 1998-11-13 2010-07-13 Georgia-Pacific Consumer Products Lp Method for maximizing water removal in a press nip

Families Citing this family (57)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19860687A1 (en) * 1998-12-29 2000-07-06 Voith Sulzer Papiermasch Gmbh Machine and method for producing a fibrous web
US6790315B2 (en) * 1999-06-17 2004-09-14 Metso Paper Karlstad Ab Drying section and method for drying a paper web
SE517618C2 (en) * 1999-10-27 2002-06-25 Stora Kopparbergs Bergslags Ab Apparatus and method in connection with the manufacture of paper or cardboard
US6413363B1 (en) * 2000-06-30 2002-07-02 Kimberly-Clark Worldwide, Inc. Method of making absorbent tissue from recycled waste paper
DE10042906A1 (en) * 2000-08-31 2002-03-14 Voith Paper Patent Gmbh Press arrangement
DE10129613A1 (en) * 2001-06-20 2003-01-02 Voith Paper Patent Gmbh Method and device for producing a fibrous web provided with a three-dimensional surface structure
DE10130038A1 (en) * 2001-06-21 2003-01-02 Voith Paper Patent Gmbh Method and machine for producing a fibrous web
US6797114B2 (en) * 2001-12-19 2004-09-28 Kimberly-Clark Worldwide, Inc. Tissue products
US6821387B2 (en) * 2001-12-19 2004-11-23 Paper Technology Foundation, Inc. Use of fractionated fiber furnishes in the manufacture of tissue products, and products produced thereby
US20030111195A1 (en) * 2001-12-19 2003-06-19 Kimberly-Clark Worldwide, Inc. Method and system for manufacturing tissue products, and products produced thereby
JP3870783B2 (en) * 2001-12-27 2007-01-24 日産自動車株式会社 Exhaust gas purification system for fuel cell vehicle and purification method for exhaust gas of fuel cell vehicle
US7150110B2 (en) * 2002-01-24 2006-12-19 Voith Paper Patent Gmbh Method and an apparatus for manufacturing a fiber web provided with a three-dimensional surface structure
DE10209582A1 (en) * 2002-03-05 2003-09-18 Voith Paper Patent Gmbh Machine for making a tissue web
US7185537B2 (en) * 2003-06-04 2007-03-06 Metso Paper, Inc. Nip and loading analysis system
CA2546004C (en) * 2003-11-12 2010-09-14 National Paintball Supply, Inc. Projectile, projectile core, and method of making
ITMI20040676A1 (en) * 2004-04-02 2004-07-02 Sca Hygiene Prod Ab APPARATUS FOR THE CONTINUOUS PRODUCTION OF A PAPER TAPE, PARTICULARLY FOR HYGIENE USE
US8293072B2 (en) 2009-01-28 2012-10-23 Georgia-Pacific Consumer Products Lp Belt-creped, variable local basis weight absorbent sheet prepared with perforated polymeric belt
DE102004052157A1 (en) * 2004-10-26 2006-04-27 Voith Fabrics Patent Gmbh Machine for producing a material web
US20070018364A1 (en) * 2005-07-20 2007-01-25 Pierre Riviere Modification of nonwovens in intelligent nips
DE102005057918A1 (en) * 2005-12-02 2007-06-06 Eduard Küsters Maschinenfabrik GmbH & Co. KG Method and device for treating a textile or nonwoven web
US7850823B2 (en) * 2006-03-06 2010-12-14 Georgia-Pacific Consumer Products Lp Method of controlling adhesive build-up on a yankee dryer
US8540846B2 (en) 2009-01-28 2013-09-24 Georgia-Pacific Consumer Products Lp Belt-creped, variable local basis weight multi-ply sheet with cellulose microfiber prepared with perforated polymeric belt
US20080176690A1 (en) * 2007-01-18 2008-07-24 Lefkowitz Leonard R Anti-rewet transfer belt
US9752283B2 (en) 2007-09-12 2017-09-05 Ecolab Usa Inc. Anionic preflocculation of fillers used in papermaking
US9181657B2 (en) * 2007-09-12 2015-11-10 Nalco Company Method of increasing paper strength by using natural gums and dry strength agent in the wet end
US8088250B2 (en) 2008-11-26 2012-01-03 Nalco Company Method of increasing filler content in papermaking
US20090184056A1 (en) * 2008-01-23 2009-07-23 Smith Kevin W Method of removing dissolved iron in aqueous systems
CA2735867C (en) 2008-09-16 2017-12-05 Dixie Consumer Products Llc Food wrap basesheet with regenerated cellulose microfiber
DE102009028215B3 (en) * 2009-08-04 2010-09-09 Voith Patent Gmbh Combination of a press felt with a press roll cover and / or a suction roll cover for a paper machine
US8968517B2 (en) 2012-08-03 2015-03-03 First Quality Tissue, Llc Soft through air dried tissue
SE536662C2 (en) * 2012-11-13 2014-05-06 Valmet Aktiebolag Yankee cylinder made of steel
PL2944720T3 (en) * 2014-05-15 2019-02-28 ICONè S.R.L. Former section and method for producing paper
US11391000B2 (en) 2014-05-16 2022-07-19 First Quality Tissue, Llc Flushable wipe and method of forming the same
US20160073686A1 (en) 2014-09-12 2016-03-17 R.J. Reynolds Tobacco Company Tobacco-derived filter element
AU2015320307A1 (en) 2014-09-25 2017-03-16 Gpcp Ip Holdings Llc Methods of making paper products using a multilayer creping belt, and paper products made using a multilayer creping belt
US9988763B2 (en) 2014-11-12 2018-06-05 First Quality Tissue, Llc Cannabis fiber, absorbent cellulosic structures containing cannabis fiber and methods of making the same
WO2016086019A1 (en) 2014-11-24 2016-06-02 First Quality Tissue, Llc Soft tissue produced using a structured fabric and energy efficient pressing
MX2017006840A (en) 2014-12-05 2018-11-09 Manufacturing process for papermaking belts using 3d printing technology.
US9950858B2 (en) 2015-01-16 2018-04-24 R.J. Reynolds Tobacco Company Tobacco-derived cellulose material and products formed thereof
US10538882B2 (en) 2015-10-13 2020-01-21 Structured I, Llc Disposable towel produced with large volume surface depressions
US10544547B2 (en) 2015-10-13 2020-01-28 First Quality Tissue, Llc Disposable towel produced with large volume surface depressions
CA3001608C (en) 2015-10-14 2023-12-19 First Quality Tissue, Llc Bundled product and system and method for forming the same
CA3012766C (en) 2016-02-08 2023-11-14 Gpcp Ip Holdings Llc Methods of making paper products using a molding roll
KR20180114109A (en) 2016-02-08 2018-10-17 쥐피씨피 아이피 홀딩스 엘엘씨 Manufacturing method of paper product using forming roll
BR112018016166B1 (en) 2016-02-08 2022-07-26 Gpcp Ip Holdings Llc ROLLER TO MOLD A FIBROUS SHEET
AU2017218159A1 (en) 2016-02-11 2018-08-30 Structured I, Llc Belt or fabric including polymeric layer for papermaking machine
US20170314206A1 (en) 2016-04-27 2017-11-02 First Quality Tissue, Llc Soft, low lint, through air dried tissue and method of forming the same
WO2018039623A1 (en) 2016-08-26 2018-03-01 Structured I, Llc Method of producing absorbent structures with high wet strength, absorbency, and softness
WO2018049390A1 (en) 2016-09-12 2018-03-15 Structured I, Llc Former of water laid asset that utilizes a structured fabric as the outer wire
US11583489B2 (en) 2016-11-18 2023-02-21 First Quality Tissue, Llc Flushable wipe and method of forming the same
US10697120B2 (en) 2017-08-08 2020-06-30 Gpcp Ip Holdings Llc Methods of making paper products using a patterned cylinder
US10619309B2 (en) 2017-08-23 2020-04-14 Structured I, Llc Tissue product made using laser engraved structuring belt
DE102018114748A1 (en) 2018-06-20 2019-12-24 Voith Patent Gmbh Laminated paper machine clothing
US11738927B2 (en) 2018-06-21 2023-08-29 First Quality Tissue, Llc Bundled product and system and method for forming the same
US11697538B2 (en) 2018-06-21 2023-07-11 First Quality Tissue, Llc Bundled product and system and method for forming the same
DE102019124681A1 (en) * 2019-09-13 2020-08-20 Voith Patent Gmbh Device and method for producing a fibrous web
IT202000020926A1 (en) 2020-09-03 2022-03-03 A Celli Paper Spa PAPER SHOE PRESS AND RELATED METHOD

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0289477A2 (en) * 1987-04-28 1988-11-02 Valmet Paper Machinery Inc. Method for hot-pressing of a paper web and a drying device for the implementation of the method
DE19654198A1 (en) * 1996-12-23 1998-06-25 Voith Sulzer Papiermasch Gmbh Machine for the production of a fibrous web
EP0854232A2 (en) * 1996-12-23 1998-07-22 Voith Sulzer Papiermaschinen GmbH Machine for the manufacture of a fibrous web

Family Cites Families (191)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3301746A (en) 1964-04-13 1967-01-31 Procter & Gamble Process for forming absorbent paper by imprinting a fabric knuckle pattern thereon prior to drying and paper thereof
US3556932A (en) 1965-07-12 1971-01-19 American Cyanamid Co Water-soluble,ionic,glyoxylated,vinylamide,wet-strength resin and paper made therewith
US3434918A (en) 1965-12-13 1969-03-25 Kimberly Clark Co Process of forming absorbent paper from a mixture of cellulosic fibers and partially crosslinked cellulosic fibers and paper thereof
US3545705A (en) 1967-04-14 1970-12-08 Jwi Ltd Stainless steel fourdrinier cloth
US3537954A (en) * 1967-05-08 1970-11-03 Beloit Corp Papermaking machine
US3549742A (en) 1967-09-29 1970-12-22 Scott Paper Co Method of making a foraminous drainage member
US3556933A (en) 1969-04-02 1971-01-19 American Cyanamid Co Regeneration of aged-deteriorated wet strength resins
US3858623A (en) 1969-06-10 1975-01-07 Huyck Corp Papermakers fabrics
US3620911A (en) 1969-07-03 1971-11-16 Beloit Corp Wet depithing of a nonwoody lignocellulosic plant material
US3772076A (en) 1970-01-26 1973-11-13 Hercules Inc Reaction products of epihalohydrin and polymers of diallylamine and their use in paper
US3700623A (en) 1970-04-22 1972-10-24 Hercules Inc Reaction products of epihalohydrin and polymers of diallylamine and their use in paper
US3691010A (en) * 1970-07-27 1972-09-12 Kimberly Clark Co Method and apparatus for dewatering paper webs
US3819470A (en) 1971-06-18 1974-06-25 Scott Paper Co Modified cellulosic fibers and method for preparation thereof
US3812000A (en) 1971-06-24 1974-05-21 Scott Paper Co Soft,absorbent,fibrous,sheet material formed by avoiding mechanical compression of the elastomer containing fiber furnished until the sheet is at least 80%dry
US3755220A (en) 1971-10-13 1973-08-28 Scott Paper Co Cellulosic sheet material having a thermosetting resin bonder and a surfactant debonder and method for producing same
US3981084A (en) * 1972-06-19 1976-09-21 Fort Howard Paper Company Closed draw transfer system with gaseous pressure direction of web
US4071050A (en) 1972-09-01 1978-01-31 Nordiska Maskinfilt Aktiebolaget Double-layer forming fabric
US3821068A (en) 1972-10-17 1974-06-28 Scott Paper Co Soft,absorbent,fibrous,sheet material formed by avoiding mechanical compression of the fiber furnish until the sheet is at least 80% dry
US3905863A (en) 1973-06-08 1975-09-16 Procter & Gamble Process for forming absorbent paper by imprinting a semi-twill fabric knuckle pattern thereon prior to final drying and paper thereof
US3926716A (en) 1974-03-19 1975-12-16 Procter & Gamble Transfer and adherence of relatively dry paper web to a rotating cylindrical surface
US3974025A (en) 1974-04-01 1976-08-10 The Procter & Gamble Company Absorbent paper having imprinted thereon a semi-twill, fabric knuckle pattern prior to final drying
SE385486B (en) 1974-10-10 1976-07-05 Nordiska Maskinfilt Ab PROPAGATION WIRE FOR PAPER, CELLULOSE OR SIMILAR MACHINES AND MANUFACTURED THE SAME
DE2517228C2 (en) 1975-04-18 1981-09-24 Hermann Wangner Gmbh & Co Kg, 7410 Reutlingen Paper machine fabric and its use in the wet end of a paper machine
US3994771A (en) 1975-05-30 1976-11-30 The Procter & Gamble Company Process for forming a layered paper web having improved bulk, tactile impression and absorbency and paper thereof
US4094718A (en) 1975-11-17 1978-06-13 E. I. Du Pont De Nemours And Company Process of preparing corrugated paper board with a particular polyvinyl alcohol modified starch-based corrugating adhesive
US4064213A (en) 1976-02-09 1977-12-20 Scott Paper Company Creping process using two-position adhesive application
SE397371C (en) 1976-02-24 1980-08-07 Nordiska Maskinfilt Ab PREPARATION VIRUS FOR PAPER, CELLULOSA OR SIMILAR MACHINES
GB1572905A (en) 1976-08-10 1980-08-06 Scapa Porritt Ltd Papermakers fabrics
GB1574341A (en) * 1976-09-13 1980-09-03 Valmet Oy Method of and means for applying suction to a web suspension layer felt forming wire or assembly of such in a paper-making machine
US4309246A (en) * 1977-06-20 1982-01-05 Crown Zellerbach Corporation Papermaking apparatus and method
US4161195A (en) 1978-02-16 1979-07-17 Albany International Corp. Non-twill paperforming fabric
US4149571A (en) 1978-03-03 1979-04-17 Huyck Corporation Papermaking fabrics
SE423118B (en) 1978-03-31 1982-04-13 Karlstad Mekaniska Ab PROCEDURE AND DEVICE FOR CONSOLIDATION AND DRYING OF A MOISTURIZED POROS COAT
US4204504A (en) 1978-05-15 1980-05-27 Dabrio John W Fuel heating, air metering valve unit for engine air inlet system
US4184519A (en) 1978-08-04 1980-01-22 Wisconsin Wires, Inc. Fabrics for papermaking machines
US4314589A (en) 1978-10-23 1982-02-09 Jwi Ltd. Duplex forming fabric
US4239065A (en) 1979-03-09 1980-12-16 The Procter & Gamble Company Papermachine clothing having a surface comprising a bilaterally staggered array of wicker-basket-like cavities
US4191609A (en) 1979-03-09 1980-03-04 The Procter & Gamble Company Soft absorbent imprinted paper sheet and method of manufacture thereof
US4304625A (en) 1979-11-13 1981-12-08 Kimberly-Clark Corporation Creping adhesives for through-dried tissue
US4300981A (en) 1979-11-13 1981-11-17 The Procter & Gamble Company Layered paper having a soft and smooth velutinous surface, and method of making such paper
US4359069A (en) 1980-08-28 1982-11-16 Albany International Corp. Low density multilayer papermaking fabric
US4376455A (en) 1980-12-29 1983-03-15 Albany International Corp. Eight harness papermaking fabric
IT1144439B (en) 1981-07-27 1986-10-29 Lavorazione Mat Plast PROCEDURE FOR THE PRODUCTION OF EXPANDED POLYSTYRENE PANELS OR SIMILAR MATERIAL DEVICE FOR THE EXECUTION OF THE PROCEDURE AND PRODUCT OBTAINED
US4379735A (en) 1981-08-06 1983-04-12 Jwi Ltd. Three-layer forming fabric
DE3146385C2 (en) 1981-11-23 1985-10-31 Hermann Wangner Gmbh & Co Kg, 7410 Reutlingen Double-layer fabric as a covering for paper machines
US4440597A (en) 1982-03-15 1984-04-03 The Procter & Gamble Company Wet-microcontracted paper and concomitant process
US4431481A (en) 1982-03-29 1984-02-14 Scott Paper Co. Modified cellulosic fibers and method for preparation thereof
FI821139L (en) * 1982-04-01 1983-10-02 Tampella Oy Ab LAONGZONSPRESS FOER EN PAPPERSMASKIN
SE441016B (en) 1982-04-26 1985-09-02 Nordiskafilt Ab PREPARATION WIRES FOR PAPER, CELLULOSA OR SIMILAR MACHINES
FI65103C (en) 1982-05-05 1984-03-12 Tampella Oy Ab LAONGZONSPRESS FOER EN PAPPERSMASKIN
US4440898A (en) 1982-06-17 1984-04-03 Kimberly-Clark Corporation Creping adhesives containing ethylene oxide/propylene oxide copolymers
JPS5938647A (en) 1982-08-28 1984-03-02 Toshiba Corp Ion selective electrode apparatus and flowing type ion analytical apparatus
FI70952C (en) 1982-10-14 1986-10-27 Valmet Oy ANORDNING MED LAONG PRESON VID PRESSBEHANDLING AV FIBERBANA
SE435739B (en) 1983-02-23 1984-10-15 Nordiskafilt Ab DOUBLE TEXTILE TYPE FORMATION WIRES
DE3307144A1 (en) 1983-03-01 1984-09-13 Hermann Wangner Gmbh & Co Kg, 7410 Reutlingen PAPER MACHINE COVERING IN A FABRIC BINDING THAT DOES NOT HAVE A SYMMETRY AXIS LONGITUDE
FI71369C (en) 1983-03-23 1986-12-19 Valmet Oy LAONGNYPPRESS FOER PAPER MASK
FI70950C (en) 1983-03-25 1986-10-27 Valmet Oy PRESSPARTI MED SLUTET DRAG I PAPPERSMASKIN
US4482601A (en) * 1983-05-31 1984-11-13 Albany International Corp. Wet press papermakers felt and method of fabrication
US4529480A (en) 1983-08-23 1985-07-16 The Procter & Gamble Company Tissue paper
US4637859A (en) 1983-08-23 1987-01-20 The Procter & Gamble Company Tissue paper
US4514345A (en) 1983-08-23 1985-04-30 The Procter & Gamble Company Method of making a foraminous member
US4528316A (en) 1983-10-18 1985-07-09 Kimberly-Clark Corporation Creping adhesives containing polyvinyl alcohol and cationic polyamide resins
US4501640A (en) 1983-10-18 1985-02-26 Kimberly-Clark Corporation Creping adhesives containing polyvinyl alcohol and cationic polyamide resins
JPS60119293A (en) 1983-11-30 1985-06-26 日本フィルコン株式会社 Papermaking fabric
US4528339A (en) 1983-12-27 1985-07-09 The Dow Chemical Company Polymerization of olefins employing catalysts prepared from novel titanium compounds
FI842114A (en) 1984-05-25 1985-11-26 Valmet Oy PRESSPARTI MED SEPARATA PRESSZON I EN PAPPERSMASKIN.
DE3501635A1 (en) 1985-01-19 1986-07-24 J.M. Voith Gmbh, 7920 Heidenheim PRESS ROLLER
US5066532A (en) 1985-08-05 1991-11-19 Hermann Wangner Gmbh & Co. Woven multilayer papermaking fabric having increased stability and permeability and method
US5114777B2 (en) 1985-08-05 1997-11-18 Wangner Systems Corp Woven multilayer papermaking fabric having increased stability and permeability and method
JPS63501158A (en) * 1985-10-03 1988-04-28 ベロイト コーポレーション Support blanket for wide nip press
US4673461A (en) 1985-11-25 1987-06-16 Beloit Corporation Enclosed shoe press with flexible end connections for its annular belt
DE3600530A1 (en) 1986-01-10 1987-07-16 Wangner Gmbh Co Kg Hermann USE OF A PAPER MACHINE TREATMENT FOR THE PRODUCTION OF TISSUE PAPER OR POROESE FLEECE AND THEREFORE SUITABLE PAPER MACHINE TENSIONING
US4709732A (en) 1986-05-13 1987-12-01 Huyck Corporation Fourteen harness dual layer weave
US4720383A (en) 1986-05-16 1988-01-19 Quaker Chemical Corporation Softening and conditioning fibers with imidazolinium compounds
US4702383A (en) 1986-08-07 1987-10-27 Filtromatic Corp. Tamper proof package
US4684439A (en) 1986-10-08 1987-08-04 Kimberly-Clark Corporation Creping adhesives containing polyvinyl alcohol and thermoplastic polyamide resins derived from poly(oxyethylene) diamine
US4788243A (en) 1986-10-08 1988-11-29 Kimberly-Clark Corporation Creping adhesives containing polyvinyl alcohol and thermoplastic polyamide resins derived from poly(oxyethylene) diamine
DE3705241A1 (en) 1986-12-24 1988-07-07 Escher Wyss Gmbh METHOD FOR MECHANICAL-THERMAL DRAINAGE OF A FIBER web
DE3708189A1 (en) 1987-03-13 1988-09-22 Voith Gmbh J M LONG NIP ROLLING PRESS
DE3713510A1 (en) 1987-04-22 1988-11-10 Oberdorfer Fa F PAPER MACHINE SCREEN FROM A DOUBLE-LAYER FABRIC
US4759976A (en) 1987-04-30 1988-07-26 Albany International Corp. Forming fabric structure to resist rewet of the paper sheet
US4788779A (en) 1987-06-15 1988-12-06 Pulp And Paper Research Institute Of Canada Method and apparatus for the rapid consolidation and/or drying of moist porous webs
US5804036A (en) 1987-07-10 1998-09-08 The Procter & Gamble Company Paper structures having at least three regions including decorative indicia comprising low basis weight regions
US5277761A (en) 1991-06-28 1994-01-11 The Procter & Gamble Company Cellulosic fibrous structures having at least three regions distinguished by intensive properties
US4886579A (en) 1988-04-29 1989-12-12 Scott Paper Company Adhesive material for creping of fibrous webs
DE3817144A1 (en) 1988-05-19 1989-11-30 Wangner Gmbh Co Kg Hermann DOUBLE-LAYER COVERING FOR THE SHEET FORMING AREA OF A PAPER MACHINE
SE461171C (en) 1988-05-25 1992-05-15 Valmet Paper Machinery Inc LONG NYP PRESSES BEFORE PAPER OR CARTON MACHINERY
SE461154B (en) 1988-05-25 1990-01-15 Valmet Paper Machinery Inc LONG NYP PRESSES BEFORE PAPER OR CARTON MACHINERY
US4883564A (en) 1988-06-01 1989-11-28 Scott Paper Company Creping device adhesive formulation
EP0346307A3 (en) 1988-06-09 1991-03-06 Nordiskafilt Ab Wet press felt to be used in a papermaking machine
US5118557A (en) * 1988-10-31 1992-06-02 Albany International Corp. Foam coating of press fabrics to achieve a controlled void volume
DE3920171A1 (en) 1988-12-21 1990-07-05 Escher Wyss Ag ROLLER WITH A ROTATABLE ROLL SHELL AND METHOD FOR OPERATING THE SAME
FI82092C (en) 1989-03-22 1991-01-10 Valmet Paper Machinery Inc long nip press
FI82274C (en) 1989-03-30 1991-02-11 Valmet Paper Machinery Inc Method of hot pressing and drying device
US4942077A (en) 1989-05-23 1990-07-17 Kimberly-Clark Corporation Tissue webs having a regular pattern of densified areas
US5054525A (en) 1989-06-23 1991-10-08 F. Oberdorfer Gmbh & Co. Double layer forming wire fabric
US4973384A (en) 1989-06-23 1990-11-27 Beloit Corporation Heated extended nip press apparatus
US5225269A (en) 1989-06-28 1993-07-06 Scandiafelt Ab Press felt
US5101574A (en) 1989-10-15 1992-04-07 Institute Of Paper, Science & Technology, Inc. Method and apparatus for drying web
US5272821A (en) 1989-10-15 1993-12-28 Institute Of Paper Science And Technology, Inc. Method and apparatus for drying web
US5098519A (en) 1989-10-30 1992-03-24 James River Corporation Method for producing a high bulk paper web and product obtained thereby
US5211815A (en) 1989-10-30 1993-05-18 James River Corporation Forming fabric for use in producing a high bulk paper web
US5025046A (en) 1989-12-15 1991-06-18 Kimberly-Clark Corporation Creping adhesive composition
FI91789C (en) 1989-12-21 1994-08-10 Tampella Oy Ab Paper machine long zone press
US5098523A (en) 1990-01-16 1992-03-24 Valmet Paper Machinery, Inc. Press roll with wedge clamp for the press jacket edges
US4976085A (en) 1990-02-28 1990-12-11 Krueger Robert E Construction plate
US4973512A (en) 1990-04-03 1990-11-27 Mount Vernon Mills, Inc. Press felt for use in papermaking machine
US5023132A (en) 1990-04-03 1991-06-11 Mount Vernon Mills, Inc. Press felt for use in papermaking machine
SE464922B (en) 1990-05-08 1991-07-01 Valmet Paper Machinery Inc PRESS ROLL
US5199467A (en) 1990-06-06 1993-04-06 Asten Group, Inc. Papermakers fabric with stacked machine direction yarns
US5167261A (en) 1990-06-06 1992-12-01 Asten Group, Inc. Papermakers fabric with stacked machine direction yarns of a high warp fill
US5103874A (en) 1990-06-06 1992-04-14 Asten Group, Inc. Papermakers fabric with stacked machine direction yarns
KR100218034B1 (en) 1990-06-29 1999-09-01 데이비드 엠 모이어 Papermaking belt and method of making the same using differential light transmission techniques
US5098522A (en) 1990-06-29 1992-03-24 The Procter & Gamble Company Papermaking belt and method of making the same using a textured casting surface
US5260171A (en) 1990-06-29 1993-11-09 The Procter & Gamble Company Papermaking belt and method of making the same using a textured casting surface
US5246544A (en) 1990-10-02 1993-09-21 James River Corporation Of Virginia Crosslinkable creping adhesives
US5087324A (en) 1990-10-31 1992-02-11 James River Corporation Of Virginia Paper towels having bulky inner layer
US5389205A (en) 1990-11-23 1995-02-14 Valmet Paper Machinery, Inc. Method for dewatering of a paper web by pressing using an extended nip shoe pre-press zone on the forming wire
US5141601A (en) 1991-01-08 1992-08-25 Valmet Paper Machinery, Inc. Press roll with wedge clamp for the press-jacket edges
US5327661A (en) 1991-01-18 1994-07-12 Institute Of Paper Science And Technology, Inc. Method and apparatus for drying web
GB9107311D0 (en) 1991-04-08 1991-05-22 Shell Int Research Process for preparing a crystalline zeolite
DE4112355A1 (en) 1991-04-16 1992-10-22 Escher Wyss Gmbh PRESS RELEASE OF A PAPER MACHINE
CA2069193C (en) 1991-06-19 1996-01-09 David M. Rasch Tissue paper having large scale aesthetically discernible patterns and apparatus for making the same
US5245025A (en) 1991-06-28 1993-09-14 The Procter & Gamble Company Method and apparatus for making cellulosic fibrous structures by selectively obturated drainage and cellulosic fibrous structures produced thereby
US5820730A (en) * 1991-06-28 1998-10-13 The Procter & Gamble Company Paper structures having at least three regions including decorative indicia comprising low basis weight regions
US5223096A (en) 1991-11-01 1993-06-29 Procter & Gamble Company Soft absorbent tissue paper with high permanent wet strength
US5167768A (en) 1991-11-07 1992-12-01 Beloit Corporation Wide nip web press and method using a press shoe with two pivots
US5171389A (en) * 1991-11-08 1992-12-15 Albany International Corp. Spiral construction of grooved long nip press
DE4138788C2 (en) 1991-11-26 1995-05-18 Escher Wyss Gmbh Device for dewatering a fibrous web
US5639351A (en) 1991-12-23 1997-06-17 Valmet Corporation Press section of a paper machine, in particular for printing paper qualities
SE469600B (en) 1991-12-23 1993-08-02 Valmet Karlstad Ab pressure shoe
US5219004A (en) 1992-02-06 1993-06-15 Lindsay Wire, Inc. Multi-ply papermaking fabric with binder warps
US5264082A (en) 1992-04-09 1993-11-23 Procter & Gamble Company Soft absorbent tissue paper containing a biodegradable quaternized amine-ester softening compound and a permanent wet strength resin
US5262007A (en) 1992-04-09 1993-11-16 Procter & Gamble Company Soft absorbent tissue paper containing a biodegradable quaternized amine-ester softening compound and a temporary wet strength resin
US5348620A (en) 1992-04-17 1994-09-20 Kimberly-Clark Corporation Method of treating papermaking fibers for making tissue
DE4216264C2 (en) 1992-05-16 2000-05-25 Voith Sulzer Papiermasch Gmbh Process for drying and loosening a paper web
US5355593A (en) 1992-06-24 1994-10-18 J.M. Voith Gmbh Device for transferring a fiber web
US5328569A (en) 1992-06-26 1994-07-12 Beloit Technologies, Inc. Curved suction box apparatus in a papermaking machine press section
DE4224730C1 (en) 1992-07-27 1993-09-02 J.M. Voith Gmbh, 89522 Heidenheim, De Tissue paper mfg. machine preventing moisture return - comprises shoe press for press unit(s) for drying tissue web, for min. press units
TW244342B (en) * 1992-07-29 1995-04-01 Procter & Gamble
DE4225297C2 (en) 1992-07-31 1996-11-28 Voith Sulzer Papiermasch Gmbh Headbox for a paper machine
US5368696A (en) 1992-10-02 1994-11-29 Asten Group, Inc. Papermakers wet press felt having high contact, resilient base fabric with hollow monofilaments
FI94267C (en) 1992-12-30 1995-08-10 Valmet Paper Machinery Inc Long nip press shoe
US5313596A (en) 1993-01-05 1994-05-17 Dell Usa Lp Motorized portable computer/expansion chassis docking system
US5382323A (en) 1993-01-08 1995-01-17 Nalco Chemical Company Cross-linked poly(aminoamides) as yankee dryer adhesives
US5281307A (en) 1993-01-13 1994-01-25 Air Products And Chemicals, Inc. Crosslinked vinyl alcohol/vinylamine copolymers for dry end paper addition
US5312522A (en) 1993-01-14 1994-05-17 Procter & Gamble Company Paper products containing a biodegradable chemical softening composition
US5320710A (en) 1993-02-17 1994-06-14 James River Corporation Of Virginia Soft high strength tissue using long-low coarseness hesperaloe fibers
FI96046C (en) 1993-03-24 1996-04-25 Valmet Paper Machinery Inc Opening procedure for a pinch in a long pinch press and plant for opening a pinch in a long pinch press
US5326434A (en) 1993-05-07 1994-07-05 Scott Paper Company Creping adhesive formulation
CA2141292A1 (en) 1993-05-29 1994-12-08 Karl Steiner Press of paper machine for thin papers
DE4318036C1 (en) 1993-05-29 1994-07-28 Voith Gmbh J M Press unit of a paper machine for the production of tissue paper
US5372876A (en) 1993-06-02 1994-12-13 Appleton Mills Papermaking felt with hydrophobic layer
DE4321268C2 (en) 1993-06-28 1996-08-14 Voith Gmbh J M Headbox and method for producing a multi-layer and multi-layer paper web
SE502125C2 (en) 1993-12-02 1995-08-28 Valmet Karlstad Ab Compact rack for a press in a paper or cardboard machine
US5374334A (en) 1993-12-06 1994-12-20 Nalco Chemical Company Class of polymeric adhesives for yankee dryer applications
US5861082A (en) * 1993-12-20 1999-01-19 The Procter & Gamble Company Wet pressed paper web and method of making the same
US5776307A (en) 1993-12-20 1998-07-07 The Procter & Gamble Company Method of making wet pressed tissue paper with felts having selected permeabilities
US5904811A (en) 1993-12-20 1999-05-18 The Procter & Gamble Company Wet pressed paper web and method of making the same
US5795440A (en) 1993-12-20 1998-08-18 The Procter & Gamble Company Method of making wet pressed tissue paper
US6423186B1 (en) * 1993-12-20 2002-07-23 The Procter & Gamble Company Apparatus and process for making structured paper and structured paper produced thereby
FI101633B1 (en) 1994-02-04 1998-07-31 Valmet Paper Machinery Inc Coupling structure between long nip rolls and method for interconnecting long nip rolls
DE4410129A1 (en) 1994-03-24 1995-09-28 Kleinewefers Gmbh Press device for sheet material
US5429686A (en) 1994-04-12 1995-07-04 Lindsay Wire, Inc. Apparatus for making soft tissue products
DE4415645A1 (en) 1994-05-04 1995-11-09 Voith Sulzer Papiermasch Gmbh Bending roller for a papermaking machine
US5569358A (en) 1994-06-01 1996-10-29 James River Corporation Of Virginia Imprinting felt and method of using the same
FI942616A (en) 1994-06-03 1995-12-04 Valmet Corp Paper web pre-press
US5897745A (en) * 1994-06-29 1999-04-27 The Procter & Gamble Company Method of wet pressing tissue paper
US5456293A (en) 1994-08-01 1995-10-10 Wangner Systems Corporation Woven papermaking fabric with diagonally arranged pockets and troughs
US5415737A (en) 1994-09-20 1995-05-16 The Procter & Gamble Company Paper products containing a biodegradable vegetable oil based chemical softening composition
FI950580A (en) 1995-02-10 1996-08-11 Valmet Corp Equipment for connecting long nip forming rollers
FI114227B (en) 1995-04-24 2004-09-15 Metso Paper Inc Paper machine with press section and dryer section
DE19515832C1 (en) 1995-04-29 1996-05-02 Voith Sulzer Papiermasch Gmbh Hydraulic piston for flexing shoe press on paper:making machine
US5618612A (en) 1995-05-30 1997-04-08 Huyck Licensco, Inc. Press felt having fine base fabric
FI98843C (en) 1995-10-03 1997-08-25 Valmet Corp A method and apparatus for removing water from a paper or board web by compression
FI955014A (en) 1995-10-20 1997-04-21 Valmet Corp Press section in a paper machine, where a long press is used
WO1997016593A1 (en) 1995-11-02 1997-05-09 Beloit Technologies, Inc. Tissue impulse dryer
US5732876A (en) 1995-11-20 1998-03-31 Bradford Company Welded partition assembly
US5700356A (en) * 1996-01-19 1997-12-23 Lefkowitz; Leonard R. Air permeable belt for dewatering web in press nip
US5657797A (en) 1996-02-02 1997-08-19 Asten, Inc. Press felt resistant to nip rejection
US6174825B1 (en) * 1997-12-09 2001-01-16 Albany International Corp. Resin-impregnated belt for application on papermaking machines and in similar industrial application
DE19756422A1 (en) * 1997-12-18 1999-06-24 Voith Sulzer Papiertech Patent Machine for producing a fibrous web, in particular a tissue paper web
ID26515A (en) * 1998-03-17 2001-01-11 Procter & Gamble EQUIPMENT AND PROCESS FOR MAKING STRUCTURED PAPER AND STRUCTURED PAPER PRODUCED.
US20020060042A1 (en) * 1998-03-20 2002-05-23 Ingvar Klerelid Paper machine for and method of manufacturing soft paper
US6171446B1 (en) * 1998-10-19 2001-01-09 Shakespeare Company Press felt with grooved fibers having improved dewatering characteristics
US6248210B1 (en) 1998-11-13 2001-06-19 Fort James Corporation Method for maximizing water removal in a press nip
DE10032251A1 (en) * 2000-07-03 2002-01-17 Voith Paper Patent Gmbh Water extraction station for a web of tissue/toilet paper has a shoe press unit at the drying cylinder with an extended press gap and a suction unit within an overpressure hood at the carrier belt
US6610173B1 (en) * 2000-11-03 2003-08-26 Kimberly-Clark Worldwide, Inc. Three-dimensional tissue and methods for making the same
US6752907B2 (en) * 2001-01-12 2004-06-22 Georgia-Pacific Corporation Wet crepe throughdry process for making absorbent sheet and novel fibrous product
US7494563B2 (en) * 2002-10-07 2009-02-24 Georgia-Pacific Consumer Products Lp Fabric creped absorbent sheet with variable local basis weight
US7442278B2 (en) * 2002-10-07 2008-10-28 Georgia-Pacific Consumer Products Lp Fabric crepe and in fabric drying process for producing absorbent sheet

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0289477A2 (en) * 1987-04-28 1988-11-02 Valmet Paper Machinery Inc. Method for hot-pressing of a paper web and a drying device for the implementation of the method
DE19654198A1 (en) * 1996-12-23 1998-06-25 Voith Sulzer Papiermasch Gmbh Machine for the production of a fibrous web
EP0854232A2 (en) * 1996-12-23 1998-07-22 Voith Sulzer Papiermaschinen GmbH Machine for the manufacture of a fibrous web

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7754049B2 (en) * 1998-11-13 2010-07-13 Georgia-Pacific Consumer Products Lp Method for maximizing water removal in a press nip
EP1111127A3 (en) * 1999-12-23 2002-01-23 Voith Paper Patent GmbH Pressing arrangement
US6488814B2 (en) 1999-12-23 2002-12-03 Voith Paper Patent Gmbh Pressing arrangement
US6860968B1 (en) 2000-05-24 2005-03-01 Kimberly-Clark Worldwide, Inc. Tissue impulse drying
DE10233920A1 (en) * 2002-07-25 2004-02-12 Voith Paper Patent Gmbh Papermaking machine dewaters tissue paper or web of fibrous hygiene web material in conjunction with a dewatering belt with reversible water take-up
DE10237826A1 (en) * 2002-08-19 2004-03-11 Voith Paper Patent Gmbh Device for the production of material webs

Also Published As

Publication number Publication date
US20020088595A1 (en) 2002-07-11
US20020088594A1 (en) 2002-07-11
US6387217B1 (en) 2002-05-14
US7754049B2 (en) 2010-07-13
CA2317438A1 (en) 2000-05-25
TR200002032T1 (en) 2001-01-22
US6458248B1 (en) 2002-10-01
WO2000029667A9 (en) 2000-11-02
US6517672B2 (en) 2003-02-11
US20030226650A1 (en) 2003-12-11
US6248210B1 (en) 2001-06-19
US20080035289A1 (en) 2008-02-14
CA2317438C (en) 2008-10-28
EP1047830A1 (en) 2000-11-02
US7300552B2 (en) 2007-11-27
US6669821B2 (en) 2003-12-30

Similar Documents

Publication Publication Date Title
US6387217B1 (en) Apparatus for maximizing water removal in a press nip
EP1116824B1 (en) Method of making absorbent sheet
US6379496B2 (en) Wet creping process
CA2367616C (en) Wet crepe throughdry process for making absorbent sheet and novel fibrous products
US7794566B2 (en) Method of making a paper web having a high internal void volume of secondary fibers
US6558510B1 (en) Wet-crepe process utilizing narrow crepe shelf for making absorbent sheet

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA TR

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

WWE Wipo information: entry into national phase

Ref document number: 1999960375

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2317438

Country of ref document: CA

WWE Wipo information: entry into national phase

Ref document number: 2000/02032

Country of ref document: TR

121 Ep: the epo has been informed by wipo that ep was designated in this application
AK Designated states

Kind code of ref document: C2

Designated state(s): CA TR

AL Designated countries for regional patents

Kind code of ref document: C2

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE

COP Corrected version of pamphlet

Free format text: PAGES 1/15-15/15, DRAWINGS, REPLACED BY NEW PAGES 1/15-15/15; DUE TO LATE TRANSMITTAL BY THE RECEIVING OFFICE

WWP Wipo information: published in national office

Ref document number: 1999960375

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1999960375

Country of ref document: EP