CA2103549A1 - Method for fiber loading a chemical compound - Google Patents
Method for fiber loading a chemical compoundInfo
- Publication number
- CA2103549A1 CA2103549A1 CA002103549A CA2103549A CA2103549A1 CA 2103549 A1 CA2103549 A1 CA 2103549A1 CA 002103549 A CA002103549 A CA 002103549A CA 2103549 A CA2103549 A CA 2103549A CA 2103549 A1 CA2103549 A1 CA 2103549A1
- Authority
- CA
- Canada
- Prior art keywords
- pulp
- accordance
- fibers
- paper
- carbon dioxide
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP 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
- D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
- D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
- D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
- D21H23/06—Controlling the addition
- D21H23/14—Controlling the addition by selecting point of addition or time of contact between components
- D21H23/16—Addition before or during pulp beating or refining
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
- D21C9/004—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives inorganic compounds
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP 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
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP 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
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/63—Inorganic compounds
- D21H17/70—Inorganic compounds forming new compounds in situ, e.g. within the pulp or paper, by chemical reaction with other substances added separately
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP 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
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/63—Inorganic compounds
- D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
- D21H17/675—Oxides, hydroxides or carbonates
Abstract
The present invention relates to a method for loading a chemical compound within the fibers of a fibrous material and to the fibrous materials produced by the method. In the method, a fibrous cellulose material is provided which consists of a plurality of elongated fibers having a fiber wall surrounding a hollow interior.
The fibrous material has a moisture content such that the level of water ranges from 40-95 % of the weight of the fibrous material and the water is positioned substantially within the hollow interior of the fibers and within the fiber walls of the fibers. A
chemical is added to the fibrous material in a manner such that the chemical is disposed in the water present in the fibrous material. The fibrous material is then contacted with a gas which is reactive with the chemical to form a water insoluble chemical compound. The method provides a fibrous material having a chemical compound loaded within the hollow interiors and within the fiber walls of the plurality of fibers.
The fibrous material has a moisture content such that the level of water ranges from 40-95 % of the weight of the fibrous material and the water is positioned substantially within the hollow interior of the fibers and within the fiber walls of the fibers. A
chemical is added to the fibrous material in a manner such that the chemical is disposed in the water present in the fibrous material. The fibrous material is then contacted with a gas which is reactive with the chemical to form a water insoluble chemical compound. The method provides a fibrous material having a chemical compound loaded within the hollow interiors and within the fiber walls of the plurality of fibers.
Description
W092/15754 21 u 3 ~ ~ ~ PCT/US92/01737 .
A ~BT~OD FO~ FIBgR LOAD~G A CEB~ICaL OO~PO~oD
Relat-d app-~ication This application is a continuation-in-part of Application Serial No. 665,464, filed March 6, 1991 entitled "A Method for Loading a Chemical Compound Within the Hollow Interior of Fibers".
Fi-ld of the Invention The present invention relates generally to a method for loading a chemical compound within the hollow interior, cell walls and on the surfaces of the ~ibers of a fibrous material. More particularly, the present invention is directed to an improved process for the production of filler-containing paper pulp in which the filler is formed in situ while in proximity to the paper pulp and a substantial portion of the filler is disposed in the lumens and cell walls of the cellulose fibers of the paper pulp, to the paper pulp produced thereby and to papers produced from such pulp.
Backq~ound of t~e In~en~ion Paper is a material made from flexible cellulose fibers which, while very short (0.02 - 0.16 in.
or 0.5 - 4 mm), are about 100 times as long as they are wide. These fibers have a strong attraction for water and for each other; when suspended in water they swell by absorption. When a suspension of a large number of such fibers in water is filtered on a wire screen, the fibers adhere weakly to one another. When more water is~removed from the mat formed on the screen by suction and by pressing, the sheet becomes stronger but is still relatively weak. When the sheet is dried, it becomes stronger, and paper is produced.
Any fibrous raw material such as wood, straw, bamboo, hemp, bagasse, sisal, flax, cotton, jute and ramie, can be used in paper manufacture. Separation of the fibers in such materials is called pulping, ~- - :'' ~. . ',' . ' , ,. ' .! , ; ~
r, .. ..
,; ' . . ~ '' ,. .'. '~' ' ~' ~ ' i`~, . ' ' .
.
, WO92/157~4 ~10~ ~ PCTtUS92/01737 regardless of the extent of purification involved in the process. The separated fibers are called pulp, whether in suspension in water as a slurry or dewatered to any degree. Pulp from a pulping process which has been dewatered to an extent such that it is no longer a slurry and has been broken up into clumps which appear to have no free water is referred to as "dewatered crumb pulp".
While dewatered crumb pulp appears to be particulate fragments, such pulp may contain up to about 95% by weight of water.
Wood is the major source of fiber for pulping because of its wide distribution and its high density compared with other plants. While any species of wood can be used, soft woods are preferred to hard woods because of their longer fibers and absence of vessels.
Wood and most other fibrous material have cellulose as their main structural component, along with hemicellulose, lignin and a large number of substances collectively called resins or extractives.
Pulping may be carried out by any of several well known processes, such as mechanical pulping, kraft pulping and sulfite pulping. An essential property of paper for many end uses is its opacity. It is particularly important in papers for printing, where it is desirable that as little as possible of the print on the reverse side of a printed sheet or on a sheet below it be visible through the paper. For printing and other applications, paper must also have a certain degree of whiteness (or brightness as it is know in the paper industry). For many paper proaucts, acceptable levels of these optical properties can be achieved from the pulp fibers alone. However, in other products, the inherent light-reflective powers of the fibers are insufficient to meet consumer demands. In such cases, the papermaker adds a filler to the papermaking furnish.
~, .
, WO92/15754 PCT/US9t/01737 213~3~9 A filler consists of fine particles of an insoluble solid, usually of a mineral origin. By virtue of the high ratio of surface area to weight (and sometimes high refractive index), the particles confer high light-reflectance to the sheet and thereby increase both opacity and brightness. Enhancement of the optical properties of the paper produced therefrom is the principal object in adding fillers to the furnish although other advantages, such as improved smoothness, lo improved printability and improved durability, can be imparted to the paper.
The increasing use of alkaline conditions in the manufacture of printing and writing papers has made it technically feasible to incorporate high loadings of alkaline fillers, such as calcium carbonate. There is an economic incentive to increase this filler loading, because when paper is sold on a weight basis (or by the sheet), the cheaper filler material effectively substitutes for the more costly fiber. In Europe, where fiber i8 more expensive, printing and writing grade papers are commonly produced containing 30-50 percent calcium carbonate; whereas only 15-20 percent loading is typically used in the United States. At the higher levels of filler loading, in order to maintain other desirable paper properties, like strength, it is necessary to use additional expensive chemical additives.
In Europe, this added expense is justifiable due to the high cost of fiber. Lower fiber cost in the United States, however, makes the use of chemical additives in order to achieve higher filler substitution less cost effective. Yet, since calcium carbonate is about 20-25 of the cost of a pulp fiber, an economical way to increase the level of pulp substitution by filler remains desirable. However, filler addition does pose some problems.
... . .
.
.~ -., , . ~
. ' ' , - ~ .
WO 92~15754 2 1 0 3 ~ ~ 9 PCr/US92/01737 One problem associated with filler addition is that the mechanical strength of the sheet is less than could be expected from the ratio of load bearing fiber to --non-load-bearing filler. The usual explanation for this 5 is that some of the filler particles become trapped between fibers, thereby reducing the strength of the fiber-to-fiber bonds which are the primary source of paper strength.
A second problem associated with the addition ~o of fillers is that a significant fraction of the small particles drain out with the water during sheet formation on the paper machine. The recovery and recycling of the particles from the drainage water, commonly known as the white water, poses a difficult problem for the 15 papermaker. In seeking to reduce this problem, many researchers have examined the manner in which filler is retained by a sheet. It has become accepted that the main mechanism is co-flocculation, i.e., the adhesion of pigment particles to the fibers. As a result of this 20 finding, major effort in filler technology has gone into increasing the adhesive forces. This work has lead to the development and use of a wide variety of soluble chemical additives known as retention aids. T~e oldest and the most widely-used of these is aluminum sulfate 25 (Papermakers' alum), but in recent years a variety of proprietary polymers have been introduced. With all of these retention aids, however, retention is still far from complete. A further mechanism of retention is filtration of pigment particles by the paper web. This 30 is relatively important with coarse fillers, but its effect is negligible with fine fillers.
U.S. Patent 4,510,020 to Green, et al.
describes a process whereby a particulate filler, such as titanium dioxide, whey or calcium carbonate, is loaded in t 35 the lumens of the cellulose fibers of paper pulp. In the method of the Green, et al. patent, the particulate . ' ~ ~ ' . ; .
', ~, ' . ....... ... ' ~ ' -`-': ~ - ;., ' ., : . -. . - ' ,:
~, W092/15754 210 3 ~ PCT/US92/01737 filler is selectively loaded within the fiber lumens by agitating a suspen~ion of pulp and filler until the fiber , lumens become loaded with filler. The method requires the use of substantially more particulate filler than can be loaded within the lumens of the fiber. Accordingly, the method reguires a step of separating the residual suspended filler from the loaded fibers by vigorously washing the pulp until substantially all of the filler on the external surfaces of the fibers is removed. Thus, ~0 the Green, et al. patent does not solve the problem referred to hereinabove wherein the filler must be recovered from the white water.
U.S. Patent No. 2,583,548 to Craig describes a process for producing a pigmented cellulosic pulp by precipitatinq pigment in and on and around the fibers.
According to the method of the Craig '548 patent, dry cellulosic fibers are added to a solution of calcium chloride. The suspension is mechanically worXed so as to effect a gelatinization of the fi~ers. The proportions of the dry cellulosic stock to the calcium chloride solution can be varied, but in general, the amount of calcium chloride present in the dilute solution is several times the weight of the cellulose fibers which are treated therewith. A second reactant, such as sodium carbonate, is then added so as to effect the precipitation of fine solid particles of calcium carbonate in and on and around the fibers. The fibers are then washed to remove the soluble by-product, which in this case is sodium chloride. The pigmented fibers produced by the Craig '548 patent contain more pigment than cellulose and when used as a paper additive are combined with-additional untreated paper pulp. The fibrous form of the pigmented additive provides good retention, but the process does have considerable limitations. The presence of filler on the fiber ...... . .
, ... . .
.. :
. ' ' ' ~ ' . : !
' ' ' ., . ~ , WO92/1~754 ,, , PCT/US92/01~37 a.,~ - 6 -surfaces and the gelatinizing effect on the fibers are detrimental to paper strength.
A modification of the '548 Craig patent is disclosed in U.S. Patent No. 2,599,09l to Craig. in the method of the Craig '09l patent, dry paper stock containing as high as 13% pulp solids is treated by the addition of solid calcium chloride to the stock. The solid calcium chloride brinqs about a profound modification of the cellulose fibers after a few minutes of agitation. The fibers become more or less gelatinous and transparent in appearance. After the treatment with calcium chloride, the stock is treated with a soluble carbonate salt in the form of a 10% solution, which is added in sufficient amount to react with the calcium chloride and precipitate an insoluble pigment of calcium carbonate. ~he resulting treated and pigmented stock is highly hydrated and has little strength or relatively much less strength than the untreated stock. The pigmented stock is then combined with untreated paper stock to provide a pigmented paper stock suitable for the preparation of paper.
U.S. Patent 3,029,181 to Thomsen is a further modification of the in situ precipitation process of the Craig patents. In the method of the Thomsen patent, the fiber is first suspended in a 10% solution of calcium chloride. Thereafter, the fiber is pressed to a moisture content of 50% and is sprayed with a concentrated solution of ammonium carbonate in an amount sufficient to precipitate all the calcium as the carbonate. The fiber is then washed to remove ammonium chloride. The washed fiber is ready for the paper machine and will usually contain approximately 10% of loading material. The Thomsen patent indicates that the method disclosed therein coats the internal area with the loading material -~5 and increases the opacity of the cellulose fibers with such internal loading.
: - ~ :
WO92/1~754 210 3 5 ~19 PCT/US92/01737 Japanese Patent Application 60-297382 to Hokuetsu Seishi describes a method for precipitating calcium carbonate in a slurry of pulp. In the method of the Hokuetsu patent, as set forth in the examples, , 5 calcium hydroxide is dispersed in a 1% slurry of beaten or unbeaten pulp. Carbon dioxide gas was then blown into the mixture of pulp slurry and calcium hydroxide to convert the calcium hydroxide to calcium carbonate.
While the Craig patents and the Thomsen patent ~0 disclose methods for the precipitation of pigment in the presence of fibers, each of the methods disclosed in these patents requires a washing step to remove the unwanted salt, i.e., sodium chloride or ammonium chloride. These methods also suffer from the aforementioned reduction in paper strength due to the gelatinizing effect on the fibers. The method of the Hokuetsu patent suffers from the fact that the calcium carbonate is precipitated in the aqueous phase of the slurry rather than a crumb pulp and is not substantially present in the lumen and cell walls of the pulp fiber.
Accordingly, it would be highly desirable to provide a method wherein a substantial amount of a filler can be dispersed within the lumens and cell walls of cellulose fibers by a simple method which is adapted to be used with existing papermaking machinery. It would also be highly desirable to provide a method for loading a chemical compound within the hollow interior and cell wall of the fibers of fibrous cellulose materials by a method which obviates the need for a subsequent washing step.
8u~ary of the Invention In a product aspect, the present invention relates to novel fibrous materials comprising a plurality of elongated fibers having a fiber wall surrounding a hollow interior and having a chemical compound loaded .
.,. : '. , . . . ' ' :
~ . . . . - , ': . . .
- : : .
WO92/lS754 PCT/US92/01737 2103~9 - 8 -within the hollow interior, within the fiber walls of the fibers and on the surface of the fibers.
In process aspects, the present invention relates to a method for producing a chemical compound in situ while in proximity to the fibers of a fibrous material. In the method, a fibrous material is provided which consists of a plurality of elongated fibers having a fiber wall surrounding a hollow interior. ~he fibrous material has a moisture content such that the level of water ranges from 40-95% of the weight of the fibrous material and the water is positioned substantially within the hollow interior of the fibers and within the fiber walls of the fibers. A chemical is added to the fibrous material in a manner such that the chemical becomes associated with the water present in the fibrous material. The fibrous material is then contacted with a gas which is reactive with the chemical to form a water insoluble chemical compound. The method provides a fibrous material having a chemical compound loaded within the hollow interiors of the fibers, within the fiber walls of the fibers and on the surface of the fibers.
While various aspects of the present invention will be described with more particularity in respect to the loading of paper pUlp, it should be understood that the method of the invention is amenable to use with other fibrous materials, which comprise a plurality of elongated fibers having a fiber wall surrounding a hollow interior and which are adapted to have a substantial amount of water dispersed in the hollow interior and fiber walls.
Desoription of th- D~awings FIGURES l-7 are plots of various parameters of paper handsheets prepared from cellulose loaded with calcium carbonate in accordance with the invention and compared with paper handsheets directly loaded on the - ., . . ~ . :
. . ' ' . !
'~
:' .
' ~ ' ' W092/15754 21~3 ' a 4 ~ PCT/US92tO1737 _ g _ ~ .
surface with calcium carbonate in accordance with a conventional methoa.
Det~iled Descr~ption of the Invention The structure of and physical properties of cellulosic fibers is an important aspect of the present invention. The most widely-used cellulosic fibers for papermaking are those derived from wood. As liberated by the pulping process, the majority of papermaking fibers appear as long hollow tubes, uniform in size for most of the length but tapered at each end. Along the length of the fiber, the fiber wall is perforated by small apertures (pits) which connect the central cavity (lumen) to the fiber exterior. It is well known that papermaking pulp can contain a high level of moisture within the cell wall and interior central cavity or lumen without appearing to be wet or without forming a slurry. An example of such pulp is referred to as "dewatered crumb pulp". The highest level of moisture that can be present in dewatered crumb pulp without providing free moisture on the surface of the pulp is dependent on the type of wood used to produce the pulp, the pulping process used to defiberize the wood and the dewatering method. The level of moisture for a particular pulp at which free water appears on the surface is referred to as the "free moisture level". At levels of moisture above the free moisture level, the pulp fibers become dispersed in the water and slurry is formed. Depending on the type of pulp, the free moisture level of the pulp can be from about 95% to about 90% of moisture, i.e., from about 5%
to about 10% of pulp. All percentages used herein are by weight and all temperatures are in degrees Fahrenheit, unless otherwise indicated.
In accordance with the present invention, dewatered crumb pulp is utilized which contains less moisture than the free moisture level. Preferably, the dewatered crumb pulp contains from about 40% to about 95%
. - . ~ . , - ., - ' ' '~
:; ' ' ':
WO92/15754 i ~ PCT/US92/01737 2103~9 - lO -of moisture, by weight, based on the total weight. In an important embodiment of the invention, it is preferred to use dewatered crumb pulp having from about 70% to about -15% of moisture, i.e., from about 85~ to about 30% of cellulose fiber.
The process of the present invention for loading fibers is applicable to a wide range of papermaking fibers. The process can be carried out on pulps derived from many species of wood by any of the common pulping and bleaching procedures. The pulp can enter the process in a "never-dried" dewatered form or it may be reconstituted with water to a level of moisture within the indicated range from a dry state.
Cellulosic fibers of diverse natural origins may be used, including soft wood fibers, hard wood fibers, cotton fibers and fibers from bagasse, hemp and flax. The fibers may be prepared by chemical pulping, however, mechanically pulped fibers, such as ground wood, thermomechanical pulp and chemithermomechanical pulp can also be used. ~he fibers may have received some mechanical treatment, such as refining or beating prior to loading the chemical compound into the lumen.
Synthetic fibers, such as hollow filament rayon, bearing accessible internal hollow structures can also be lumen-loaded by the process of the invention.
Further in accordance with the invention,calcium oxide (lime) or calcium hydroxide is mixed with dewatered crumb pulp having the desired level of moisture. In this connection, the calcium oxide can be added to the water used for reconstituting dried fibers prior to adding the water to the fibers. Upon adding the calcium oxide to a dewatered crumb pulp and simple mixing for a period of a few minutes, the calcium oxide (as a white powder) combines with the water to form calcium hydroxide within the mass of fibers in the pulp. Since both calcium oxide and calcium hydroxide are both - , ~ .
:.
WO92/15754 2i ~ PCT/US92/01737 relatively insoluble in water (1.2 and 1.6 grams per liter, respectively) and there is no substantial free surface moisture on the fibers, the mechanism whereby the calcium oxide is drawn into the water located in the hollow fiber interior and the fiber walls is not completely understood. Calcium oxide, however, reacts vigorously with water in an exothermic reaction to produce calcium hydroxide, enough for 100 grams of quicklime to heat 200 grams of water from 0- F. to boiling. ~hile not wishing to be bound by any theory, it is believed that the calcium oxide reacts with water at the surface openings of the fiber-to form calcium hydroxide and that the calcium hydroxide is drawn into the cell walls and hollow interior of the cellulose fibers by hydrostatic forces. For this reason, the highly reactive forms of calcium oxide (quicklime) are preferably used in the process of the invention. The less reactive forms, such as dolomitic limestone and dead burned limestone are less suitable.
The calcium oxide or calcium hydroxide may be added at any desired level up to about 50%, based on the weight of the dry cellulosic material. The lower limit for addition of the calcium oxide may be as low as desired, but is preferably not less than about 0.1%.
Most preferably, the calcium oxide or calcium hydroxide is present at a level of from about 10% to about 40%, based on the weight of the dry cellulosic material. The carbon dioxide is added at a level sufficient to cause complete reaction of the chemical with the gas to form the water insoluble chemical compound. Excess gas can be used since no further reaction takes place. Since there is no extraneous chemical material formed, such as would be the case with precipitating a water-insoluble chemical compound with two water soluble salts, there is no need to wash the cellulosic material after treatment with carbon dioxide in accordance with the invention to load ..., ., , . ~ -, , , ~ -WO92/1~754 PCT/US92/01737 21~5~9 - 12 -the fibers with the precipitated calcium carbonate. In the case of paper pulp, the paper pulp can be immediately transferred to a papermaking operation where it is formed into a slurry, refined and placed onto a Fourdrinier S machine or other suitable papermaking apparatus.
Alternatively, the paper pulp having the chemical compound loaded therein may be further dried and shipped as an item of commerce to a papermaking facility for subsequent usage.
It has been determined that the precipitation of calcium carbonate in cellulosic fibers containing from about 40% to about 85% of moisture (15~ to 60% of fiber) and loaded with from about 10% to about 40% of calcium oxide or calcium hydroxide is easily effected in a pressurized container with low shear mixing. The carbon dioxide pressure in the container is preferably from about 5 psig to about 60 psig and the low shear mixing is preferably continued for a period of from about l minute to about 60 minutes.
It has also been determined that for fibers containing from about 95% to about 85% of moisture (5% to 15%) of fiber) and the same calcium oxide loading, that high shear treatment during contact with the carbon dioxide is required to cause complete precipitation of calcium carbonate. In this connection, any suitable high shear mixing device can be used. Preferably, the high shear treatment is sufficient to impart from about lO to about 70 watt hours of energy per kilo of fiber, dry weight basis.
It has been determined that a simple way to provide contact of the carbon dioxide with the paper pulp under high shear treatment is by means of a pressurized refiner. The pressurized refiner is a well known piece of apparatus utilized in the papermaking industry and consists of a cylindrical hopper into which the paper pulp is loaded. The cylindrical hopper is gas tight and ~ : - - ,. : .
...
.:. . . : -' ' ' - ' :
: ' ' 2 ~
can be pressurized with a gas. A rotating shaft containing beater arms is disposed within the hopper to keep the paper pulp from matting. An auger screw is located beneath the hopper for conveying the paper pulp into the interior space between a set of matched discs.
one of the discs is stationary whereas the opposing disk is driven by means of a motor. The discs are spaced apart by a distance sufficient to shred the pulp crumbs as the pulp passes between the stationary disk and the revolving disk. The discs may be provided with refining surfaces. The use of a "devil's tooth" plate, or fiberizing plate, has also been found to be suitable.
Prior to forcing the pulp into contact with the rotating plate, the carbon dioxide is pumped into the sealed hopper to pressurized the hopper with carbon dioxide and remains in contact with the pulp while the paper pulp is stirred in the hopper and while the pulp is being transported by the auger through the refiner discs.
It has also been determined that it is not possible to effect the reaction between the calcium oxide or calcium hydroxide and the carbon dioxide by blowing the carbon dioxide through the mixture of dewatered crumb pulp and the calcium oxide or calcium hydroxide.
Through an investigation of handsheets prepared in accordance with the invention, it has been determined that about 50% of the precipitated calcium carbonate is retained by the pulp fibers. The remaining 50% is recovered as white water which can be used to fill paper on the papermaking machine in accordance with conventional surface filling processes. The retained calcium carbonate is distributed approximately equally in the lumen, within the cell walls of the cellulose fibers and on the surface of the cellulose fibers. A higher level of retention is attained by precipitation of calcium carbonate in a pressurized container with low shear than through use of the pressurized refiner. The : - - : , , , : :
; :, . I , . , - .
W092/1~7~4 i PCT/US92/01737 210~54~` - 14 -quality of handsheets prepared from pulp wherein the ?
precipitation is effected with the pressurized refiner is, however, superior.
The following example further illustrates 5 various features of the invention, but is intended to in no way limit the scope of the invention as set forth in the appended claims.
Materials Pulp - The pulps used were a softwood pulp 10 mixture and a hardwood pulp mixture that were supplied by Consolidated Paper Company and refined further in a single disk refiner to pulp freenesses of 410 and 180 (CSF) for the softwood, and 395 and 290 (CSF) for the hardwood.
Calcium reactants - Calcium oxide used was a technical grade (Fisher Chemical Company) or a high reactivity Continental lime (Marblehead Lime Co.).
Reagent grade calcium hydroxide (Aldrich Chemical) was also used. For the direct loading comparison, papermaker 20 grade calcium carbonate (Pfizer) was used.
Equip~en~
Mixer - A bench-model 3-speed Hobart food mixer with a 20 quart stainless steel bowl and flat beater was used for mixing the calcium reactants with the pulp.
Refiner - A Sprout-Bauer pressurized disk refiner was used as both the reaction chamber and refiner ~ -for precipitating calcium carbonate and incorporating it into pulp fibers.
Filtering centrifuge - This 2-speed centrifuge is eguipped with a perforated vessel lined with a canvas bag to filter a continuous flow of low consistency slurries.
Bauer-McNett Fiber Analyzer - An industry standard method for determining non-leachable filler retention.
.
- :
' ' '' ' ' ~' ' ' ' .
.
- . . . , . :
- '- . . ' ' . : ~ . - .
:
. .
2 1 ~ 3 ~ ~ 9 PCT/US92/01737 Muffle furnace - A Thermodyne furnace was used r ashing samples.
pical Refiner Run Procedure Hobart - For each run, 1 kg pulp (based on dry weight of fiber) was blended in the Hobart mixer with - varying amounts of calcium reactant and water required for a specific chemical load and consistency. The pulp was mixed for 15 minutes at low speed (approxim~tely 110 rpm) to uniformly incorporate the calcium.
lo Refiner - The high consistency pulp was then - loaded into the hopper of the refiner which was closed and sealed. Carbon dioxide was injected into the hopper to react with the calcium hydroxide. Carbon dioxide was held in the tank at 20 lbs. pressure for 15 minutes.
During this interval, calcium carbonate was precipitated in the pulp fibers by the reaction of calcium oxide or calcium hydroxide with the carbon dioxide. The pulp is then refined in a carbon dioxide atmosphere at the desired plate gap and feed rate to provide intimate contact of the carbonate and fibers.
Direct loading - For comparisons, pulps were -loaded directly with calcium carbonate without the aid of the pressurized refiner. Pulp for direct loading was fiberized in the British Disintegrator according to Tappi 25 Standard T-205 for 60g/m2 handsheet preparation and poured into the doler tank. Varying amounts of calcium carbonate was added to the low consistency pulp slurry in the doler tank and stirred to assure uniform distribution prior to maXing handsheets.
Centrifuging - In order to avoid the high consistency mixing step using the Hobart mixer, pulps were sometimes loaded with calcium oxide or calcium hydroxide at low consistency and then dewatered. Pulp and the calcium reactant was stirred at 2% consistency with an air stirrer for 15 minutes. The pulp slurry was then fed into the filtering centrifuge to dewater the . . ', ~ ~ `
: ' ' . ....
WO92/15754 . PCT/US92/01737 21~3~4~ - 16 -pulp to approximately 30% consistency. The pulp was removed from the centrifuge bag, shredded and loaded into the pressurized refiner for reaction with carbon dioxide.
TEST ME3~LODS
Scanning Electron Microscopy (SEM) - SEM
observations and X-ray microanalysis was carried out on transverse sections of pulp fibers and handsheets.
Sections were hand-cut with a razor blade. The dry pulps and strips of handsheets (1 cm x 0.3 cm) were cemented to aluminum stubs and sputter-coated with gold. Samples were photographed in a JEOL 840 SEM at an accelerating voltage of 20 kv.
SEM X-ray microanalysis - Samples were prepared as for SEM observation, but were adhered to carbon specimen stubs and coated with a conductive carbon layer.
X-ray microanalysis was performed with a Tracor Northern T-2000/4000 energy-dispersive spectrometer in combination with the scanning electron microscope. The microanalysis spectra were recorded in an energy range of 15 keV.
The specimen preparation procedures for x-ray analysis make it necessary for controls to be employed if x-ray data are to be compared with any validity. The samples of pulp and handsheets were dried at the same time, under the same conditions. This eliminates variations arising from inconsistencies in procedures.
Once a sample is dried, care was taken to keep it free of moisture. The samples were not exposed to room air and not stored in a desiccator with chemical desiccants for fear of elemental contamination. All x-ray data to be compared was obtained with the same specimen current for biological x-ray microanalysis.
Ca~konate Test Pulp and handsheet specimens were placed in 1%
aqueous silver nitrate for 30 minutes, rinsed in distilled water and placed in 5% aqueous sodium thiosulfate for 3 minutes and washed in tap water (Van ', ' ' ',.' ~ .' . ~ ' '~, . ' .
WO92/1~754 2 1~3 ~ PCT/US92/01737 Kossa's method for carbonates). Carbonate groups (calcium) stain black. Rapid spot tests were run on samples to confirm the presence of carbonates.
Pulp/Paper Tests As each filled pulp sample was discharged from the refiner, a random sample was taken for the determination of freeness, pH and ash content. Ash content of the pulp was assessed by Tappi Method T-211.
Handsheets (60g/m2) were prepared from the pulp by standard Tappi Method T-205. Again, the ash content was determined on the handsheet, and the percent retention is reported as the percent filler in the handsheet based on the percent filler in the pulp (and subtracting the small blank of the pulp's original ash content). Percent lS retention, therefore, represents the filler retention that stays with the pulp during standard handsheet formation. Another sample of pulp from the refiner discharge was subjected to a thorough washing (20 minutes) with tap water in a chamber of a Bauer-McNett fiber fractionator and collected on a 200 mesh screen.
The ash content was determined on this Bauer-McNett --washed pulp sample, and is identified in the data tables as B/M ash%.
The handsheets were used for evaluation of burst index and for the evaluation of optical properties.
Burst index, as determined by Tappi Method T-403, is a convenient measure of strength and an accepted measure of fiber bonding. Densities of the handsheets were measured according to Tappi Method T-220 and appeared to correlate meaningfully with both freeness and burst index. Optical properties of brightness, opacity and scattering coefficient were determined on a Technidyne photometer.
Spread sheets of all the test data obtained on the pulp and handsheets are attached in the appendix.
, ... ..
- ~-, .
. -.
WO92/1~754 ~ PCT/US92/01737 2103~49 - 18 -SEM
Initial loading experiments using CaO indicated that rhombohedral calcite crystals in the 1 to 3 micron size were attained, as evidenced by electron microscopy.
Scanning electron microscopy of the cross-sections of pulp and handsheet fibers showed that calcium carbonate was precipitated as discrete angular particles, i.e., crystals. Crystalline aggregates can be seen in the lumen and on the surface. The distinctive spectrum of calcium is found within the cell-wall as well as on the fiber surface and in the cell lumen. This latter information indicates that a portion of the calcium ions can diffuse into the fiber wall as well. Calcium carbonate was confirmed to be in the lumen and on the surface of pulp and handsheet fibers.
Table 1 is a comparison of the burst and optical properties (at the same initial freeness) of refiner-run handsheets. The two numbers in parentheses, such as (15,20), indicate the pulp consistency and the calcium reactant loading, respectively. Also for comparison, are the burst and optical properties of handsheets in which the filler loading was obtained by direct addition during handsheet formation of papermaker's grade carbonate (Pfizer). The results in Table 1 are also presented in the FIGURES 1-7. If scattering coefficient, opacity or brightness are plotted versus burst index, FIGURES 1-7 points from the fiber loaded handsheets lie approximately on the same curves as the points from the direct-loaded handsheets. These plots indicate the expected inverse relationship between optical properties and strength; that is, as burst - strength increases, the desirable optical properties decreases. The fact that both fiber loaded handsheets and direct loaded handsheets of the invention lie on the same curves means that for any given gain in optical properties, one should expect a comparable loss in ~-: ' , : ,:, -, ~ , -,.............. . - - : - :
.: . . , -.
: , - : .
,' ~ , ' ~: ' ' ,, - - , , ~ , , , : , , ' '' . .: " .' . -.~ , , .
- - - WO 92t1~;75~ 21~ 3 ~ 'i 9 PCr/US92/01737 strength properties regardless of how the filler is incorporated.
T~ble 1 C~IP~RISO~I OF WRST ~IID CPTIC~- PROPERTIES
5~T~EEN F10ER ~,~pED ~ DIRECT LOADED H~IIDSNEETS
P. Sc~tt ~rightnessOp city Coeff Density aurst Index P~per Ash 9/11 Ash Type ~X) ~X~2/ltg)~ltc~m3) ~ .mVg) ~X) ~X) CTRL-al.HU~395) 87.7 78.5 47.7 717.7 3.14 0.24 --10 46X D.C~CO3 90.6 87.2 101.6 648.4 1.12 16.25 --36X D.C C03 90.3 86.2 93.0 651.6 1.26 12.35 0.35 ~ 27X D.C-C03 89.6 84.6 79.6 671.7 1.65 8.80 0.35 16X D.C-CD3 U.5 81.5 60.4 676.2 2.03 4.10 --12X D.C C03 U.l 81.5 58.2 687.2 2.23 3.02 --15 10X D.C CO3 U.6 81.5 60.3 679.2 2.12 3.83 --5X D.C-CO387.8 79.5 53.5 696.0 2.57 1.74 --Ru~ 4214 ~21,20)89.082.2 64.1 722.6 1.70 9.82 4.19 Rm ~233 ~21,20) U.8 82.5 63.9 750.8 1.92 10.U 5.34 Ru~ #243 ~21,20)U.7 82.2 62.6 741.1 1.86 9.38 3.80 20 Rvl #245 ~21,20)88.~82.4 64.0 738.5 1.81 9.51 3.30 Rv~ #275 ~21,20)88.682.2 63.1 737.1 1.78 9.16 3.34 Rv~ #265 ~21,20~U.7 83.0 66.7 727.2 1.71 10.17 3.77 R~ #213 ~18,20)88.8 82.2 64.3 736.3 1.80 10.04 3.59 Uu~ #217 ~18,30)90.0 K.5 78.9 719.2 1.27 15.39 5.22 25 Ru~ ~211 ~15,20)88.882.7 65.1 712.6 2.10 10.58 3.54 Rul #218 ~18,10)87.879.8 53.2 r20.7 2.34 5.11 2.69 FIGURE 4 is a plot of burst index versus ash content. The direct loaded handsheets lie on a smooth curve; again demonstrating that as the ash content increases, the burst strength decreases. The points from the fiber-loaded handsheets are plotted in the same figure and all of the fiber-loaded handsheets lie considerably above the direct-loaded curve. This means that at comparable ash contents, the fiber-loaded handsheets of the invention are considerably stronger.
The converse also holds true, as seen in FIGURES 5-7, when optical properties are plotted versus ash content.
At equal ash content, the direct-loaded handsheets exhibit better optical properties than the fiber-loaded handsheets of the invention.
. .
.
WO92/1~7~4 PCT/US92/01737 2103~'~9 - 20 -Conclusions It has been demonstrated that fiber loading with calcium carbonate can be accomplished by an in situ --reaction between calcium oxide (or hydroxide) and carbon dioxide in high consistency dewatered crumb pulps. A
pressurized Sprout-Bauer disk refiner adequately serves as both reaction chamber and as a means for obtaining a good dispersion of filler and fiber. SEM examination has revealed the presence of calcium carbonate crystals on both external fiber surfaces and within the cell lumen;
and x-ray microprobe analysis indicates the presence of calcium within the cell wall. Optimum conditions for fiber loading using the pressurized refiner occur at pulp consistency of 18% for softwood pulp and 21% for hardwood 15 pulp.
In some respects, handsheet properties prepared from fiber-loaded pulp outperformed direct loaded handsheets. When compared at equal filler content and equal freeness, the fiber-loaded handsheet exhibited greater bursting strength. This indicates that comparable burst strength can be obtained at higher ash content for handsheets made from fiber loaded pulp than handsheets made from direct loaded pulp. Also, at the same burst strengths, similar optical properties are obtained. This permits lower cost calcium carbonate to be substituted for higher cost fiber at no loss in burst or optical properties. This is a potential large æaving in papermaking costs.
At equal ash contents, the poorer optical -properties in comparison to the direct loaded sheets is partly understandable because the papermakers' carbonate was specifically designed in terms of crystal morphology and particle size to achieve maximum scattering power.
In addition, filler in close contact with cell-wall material (as for example inside cell lumen) may inherently scatter less because the difference in .' ~ : , ' ~ ,,.
W092/1~7~ PCT/~S92/0173/
21û3~9 refractive index between filler and cell-wall material is smaller than the difference in refractive index between filler and air.
.
. . ~. . , . : ~ ..
-.,: ' ' ' ' ` ', ' ' '' ` ' ' '' ' ' ' . , ~ ' ',, ' " ' ' ' '.: ',, ' ~ ' ' ' ' ~ .' ', ., , . : , .. : ' , ~
,' .' ,. ' , ' ':
: ' . . ' . . ` ' ,...
', : , :' ~:' ~ . ` . '.
~,' ' '; ' ' ~ ' ,' ., ' '' '''' ' ~
A ~BT~OD FO~ FIBgR LOAD~G A CEB~ICaL OO~PO~oD
Relat-d app-~ication This application is a continuation-in-part of Application Serial No. 665,464, filed March 6, 1991 entitled "A Method for Loading a Chemical Compound Within the Hollow Interior of Fibers".
Fi-ld of the Invention The present invention relates generally to a method for loading a chemical compound within the hollow interior, cell walls and on the surfaces of the ~ibers of a fibrous material. More particularly, the present invention is directed to an improved process for the production of filler-containing paper pulp in which the filler is formed in situ while in proximity to the paper pulp and a substantial portion of the filler is disposed in the lumens and cell walls of the cellulose fibers of the paper pulp, to the paper pulp produced thereby and to papers produced from such pulp.
Backq~ound of t~e In~en~ion Paper is a material made from flexible cellulose fibers which, while very short (0.02 - 0.16 in.
or 0.5 - 4 mm), are about 100 times as long as they are wide. These fibers have a strong attraction for water and for each other; when suspended in water they swell by absorption. When a suspension of a large number of such fibers in water is filtered on a wire screen, the fibers adhere weakly to one another. When more water is~removed from the mat formed on the screen by suction and by pressing, the sheet becomes stronger but is still relatively weak. When the sheet is dried, it becomes stronger, and paper is produced.
Any fibrous raw material such as wood, straw, bamboo, hemp, bagasse, sisal, flax, cotton, jute and ramie, can be used in paper manufacture. Separation of the fibers in such materials is called pulping, ~- - :'' ~. . ',' . ' , ,. ' .! , ; ~
r, .. ..
,; ' . . ~ '' ,. .'. '~' ' ~' ~ ' i`~, . ' ' .
.
, WO92/157~4 ~10~ ~ PCTtUS92/01737 regardless of the extent of purification involved in the process. The separated fibers are called pulp, whether in suspension in water as a slurry or dewatered to any degree. Pulp from a pulping process which has been dewatered to an extent such that it is no longer a slurry and has been broken up into clumps which appear to have no free water is referred to as "dewatered crumb pulp".
While dewatered crumb pulp appears to be particulate fragments, such pulp may contain up to about 95% by weight of water.
Wood is the major source of fiber for pulping because of its wide distribution and its high density compared with other plants. While any species of wood can be used, soft woods are preferred to hard woods because of their longer fibers and absence of vessels.
Wood and most other fibrous material have cellulose as their main structural component, along with hemicellulose, lignin and a large number of substances collectively called resins or extractives.
Pulping may be carried out by any of several well known processes, such as mechanical pulping, kraft pulping and sulfite pulping. An essential property of paper for many end uses is its opacity. It is particularly important in papers for printing, where it is desirable that as little as possible of the print on the reverse side of a printed sheet or on a sheet below it be visible through the paper. For printing and other applications, paper must also have a certain degree of whiteness (or brightness as it is know in the paper industry). For many paper proaucts, acceptable levels of these optical properties can be achieved from the pulp fibers alone. However, in other products, the inherent light-reflective powers of the fibers are insufficient to meet consumer demands. In such cases, the papermaker adds a filler to the papermaking furnish.
~, .
, WO92/15754 PCT/US9t/01737 213~3~9 A filler consists of fine particles of an insoluble solid, usually of a mineral origin. By virtue of the high ratio of surface area to weight (and sometimes high refractive index), the particles confer high light-reflectance to the sheet and thereby increase both opacity and brightness. Enhancement of the optical properties of the paper produced therefrom is the principal object in adding fillers to the furnish although other advantages, such as improved smoothness, lo improved printability and improved durability, can be imparted to the paper.
The increasing use of alkaline conditions in the manufacture of printing and writing papers has made it technically feasible to incorporate high loadings of alkaline fillers, such as calcium carbonate. There is an economic incentive to increase this filler loading, because when paper is sold on a weight basis (or by the sheet), the cheaper filler material effectively substitutes for the more costly fiber. In Europe, where fiber i8 more expensive, printing and writing grade papers are commonly produced containing 30-50 percent calcium carbonate; whereas only 15-20 percent loading is typically used in the United States. At the higher levels of filler loading, in order to maintain other desirable paper properties, like strength, it is necessary to use additional expensive chemical additives.
In Europe, this added expense is justifiable due to the high cost of fiber. Lower fiber cost in the United States, however, makes the use of chemical additives in order to achieve higher filler substitution less cost effective. Yet, since calcium carbonate is about 20-25 of the cost of a pulp fiber, an economical way to increase the level of pulp substitution by filler remains desirable. However, filler addition does pose some problems.
... . .
.
.~ -., , . ~
. ' ' , - ~ .
WO 92~15754 2 1 0 3 ~ ~ 9 PCr/US92/01737 One problem associated with filler addition is that the mechanical strength of the sheet is less than could be expected from the ratio of load bearing fiber to --non-load-bearing filler. The usual explanation for this 5 is that some of the filler particles become trapped between fibers, thereby reducing the strength of the fiber-to-fiber bonds which are the primary source of paper strength.
A second problem associated with the addition ~o of fillers is that a significant fraction of the small particles drain out with the water during sheet formation on the paper machine. The recovery and recycling of the particles from the drainage water, commonly known as the white water, poses a difficult problem for the 15 papermaker. In seeking to reduce this problem, many researchers have examined the manner in which filler is retained by a sheet. It has become accepted that the main mechanism is co-flocculation, i.e., the adhesion of pigment particles to the fibers. As a result of this 20 finding, major effort in filler technology has gone into increasing the adhesive forces. This work has lead to the development and use of a wide variety of soluble chemical additives known as retention aids. T~e oldest and the most widely-used of these is aluminum sulfate 25 (Papermakers' alum), but in recent years a variety of proprietary polymers have been introduced. With all of these retention aids, however, retention is still far from complete. A further mechanism of retention is filtration of pigment particles by the paper web. This 30 is relatively important with coarse fillers, but its effect is negligible with fine fillers.
U.S. Patent 4,510,020 to Green, et al.
describes a process whereby a particulate filler, such as titanium dioxide, whey or calcium carbonate, is loaded in t 35 the lumens of the cellulose fibers of paper pulp. In the method of the Green, et al. patent, the particulate . ' ~ ~ ' . ; .
', ~, ' . ....... ... ' ~ ' -`-': ~ - ;., ' ., : . -. . - ' ,:
~, W092/15754 210 3 ~ PCT/US92/01737 filler is selectively loaded within the fiber lumens by agitating a suspen~ion of pulp and filler until the fiber , lumens become loaded with filler. The method requires the use of substantially more particulate filler than can be loaded within the lumens of the fiber. Accordingly, the method reguires a step of separating the residual suspended filler from the loaded fibers by vigorously washing the pulp until substantially all of the filler on the external surfaces of the fibers is removed. Thus, ~0 the Green, et al. patent does not solve the problem referred to hereinabove wherein the filler must be recovered from the white water.
U.S. Patent No. 2,583,548 to Craig describes a process for producing a pigmented cellulosic pulp by precipitatinq pigment in and on and around the fibers.
According to the method of the Craig '548 patent, dry cellulosic fibers are added to a solution of calcium chloride. The suspension is mechanically worXed so as to effect a gelatinization of the fi~ers. The proportions of the dry cellulosic stock to the calcium chloride solution can be varied, but in general, the amount of calcium chloride present in the dilute solution is several times the weight of the cellulose fibers which are treated therewith. A second reactant, such as sodium carbonate, is then added so as to effect the precipitation of fine solid particles of calcium carbonate in and on and around the fibers. The fibers are then washed to remove the soluble by-product, which in this case is sodium chloride. The pigmented fibers produced by the Craig '548 patent contain more pigment than cellulose and when used as a paper additive are combined with-additional untreated paper pulp. The fibrous form of the pigmented additive provides good retention, but the process does have considerable limitations. The presence of filler on the fiber ...... . .
, ... . .
.. :
. ' ' ' ~ ' . : !
' ' ' ., . ~ , WO92/1~754 ,, , PCT/US92/01~37 a.,~ - 6 -surfaces and the gelatinizing effect on the fibers are detrimental to paper strength.
A modification of the '548 Craig patent is disclosed in U.S. Patent No. 2,599,09l to Craig. in the method of the Craig '09l patent, dry paper stock containing as high as 13% pulp solids is treated by the addition of solid calcium chloride to the stock. The solid calcium chloride brinqs about a profound modification of the cellulose fibers after a few minutes of agitation. The fibers become more or less gelatinous and transparent in appearance. After the treatment with calcium chloride, the stock is treated with a soluble carbonate salt in the form of a 10% solution, which is added in sufficient amount to react with the calcium chloride and precipitate an insoluble pigment of calcium carbonate. ~he resulting treated and pigmented stock is highly hydrated and has little strength or relatively much less strength than the untreated stock. The pigmented stock is then combined with untreated paper stock to provide a pigmented paper stock suitable for the preparation of paper.
U.S. Patent 3,029,181 to Thomsen is a further modification of the in situ precipitation process of the Craig patents. In the method of the Thomsen patent, the fiber is first suspended in a 10% solution of calcium chloride. Thereafter, the fiber is pressed to a moisture content of 50% and is sprayed with a concentrated solution of ammonium carbonate in an amount sufficient to precipitate all the calcium as the carbonate. The fiber is then washed to remove ammonium chloride. The washed fiber is ready for the paper machine and will usually contain approximately 10% of loading material. The Thomsen patent indicates that the method disclosed therein coats the internal area with the loading material -~5 and increases the opacity of the cellulose fibers with such internal loading.
: - ~ :
WO92/1~754 210 3 5 ~19 PCT/US92/01737 Japanese Patent Application 60-297382 to Hokuetsu Seishi describes a method for precipitating calcium carbonate in a slurry of pulp. In the method of the Hokuetsu patent, as set forth in the examples, , 5 calcium hydroxide is dispersed in a 1% slurry of beaten or unbeaten pulp. Carbon dioxide gas was then blown into the mixture of pulp slurry and calcium hydroxide to convert the calcium hydroxide to calcium carbonate.
While the Craig patents and the Thomsen patent ~0 disclose methods for the precipitation of pigment in the presence of fibers, each of the methods disclosed in these patents requires a washing step to remove the unwanted salt, i.e., sodium chloride or ammonium chloride. These methods also suffer from the aforementioned reduction in paper strength due to the gelatinizing effect on the fibers. The method of the Hokuetsu patent suffers from the fact that the calcium carbonate is precipitated in the aqueous phase of the slurry rather than a crumb pulp and is not substantially present in the lumen and cell walls of the pulp fiber.
Accordingly, it would be highly desirable to provide a method wherein a substantial amount of a filler can be dispersed within the lumens and cell walls of cellulose fibers by a simple method which is adapted to be used with existing papermaking machinery. It would also be highly desirable to provide a method for loading a chemical compound within the hollow interior and cell wall of the fibers of fibrous cellulose materials by a method which obviates the need for a subsequent washing step.
8u~ary of the Invention In a product aspect, the present invention relates to novel fibrous materials comprising a plurality of elongated fibers having a fiber wall surrounding a hollow interior and having a chemical compound loaded .
.,. : '. , . . . ' ' :
~ . . . . - , ': . . .
- : : .
WO92/lS754 PCT/US92/01737 2103~9 - 8 -within the hollow interior, within the fiber walls of the fibers and on the surface of the fibers.
In process aspects, the present invention relates to a method for producing a chemical compound in situ while in proximity to the fibers of a fibrous material. In the method, a fibrous material is provided which consists of a plurality of elongated fibers having a fiber wall surrounding a hollow interior. ~he fibrous material has a moisture content such that the level of water ranges from 40-95% of the weight of the fibrous material and the water is positioned substantially within the hollow interior of the fibers and within the fiber walls of the fibers. A chemical is added to the fibrous material in a manner such that the chemical becomes associated with the water present in the fibrous material. The fibrous material is then contacted with a gas which is reactive with the chemical to form a water insoluble chemical compound. The method provides a fibrous material having a chemical compound loaded within the hollow interiors of the fibers, within the fiber walls of the fibers and on the surface of the fibers.
While various aspects of the present invention will be described with more particularity in respect to the loading of paper pUlp, it should be understood that the method of the invention is amenable to use with other fibrous materials, which comprise a plurality of elongated fibers having a fiber wall surrounding a hollow interior and which are adapted to have a substantial amount of water dispersed in the hollow interior and fiber walls.
Desoription of th- D~awings FIGURES l-7 are plots of various parameters of paper handsheets prepared from cellulose loaded with calcium carbonate in accordance with the invention and compared with paper handsheets directly loaded on the - ., . . ~ . :
. . ' ' . !
'~
:' .
' ~ ' ' W092/15754 21~3 ' a 4 ~ PCT/US92tO1737 _ g _ ~ .
surface with calcium carbonate in accordance with a conventional methoa.
Det~iled Descr~ption of the Invention The structure of and physical properties of cellulosic fibers is an important aspect of the present invention. The most widely-used cellulosic fibers for papermaking are those derived from wood. As liberated by the pulping process, the majority of papermaking fibers appear as long hollow tubes, uniform in size for most of the length but tapered at each end. Along the length of the fiber, the fiber wall is perforated by small apertures (pits) which connect the central cavity (lumen) to the fiber exterior. It is well known that papermaking pulp can contain a high level of moisture within the cell wall and interior central cavity or lumen without appearing to be wet or without forming a slurry. An example of such pulp is referred to as "dewatered crumb pulp". The highest level of moisture that can be present in dewatered crumb pulp without providing free moisture on the surface of the pulp is dependent on the type of wood used to produce the pulp, the pulping process used to defiberize the wood and the dewatering method. The level of moisture for a particular pulp at which free water appears on the surface is referred to as the "free moisture level". At levels of moisture above the free moisture level, the pulp fibers become dispersed in the water and slurry is formed. Depending on the type of pulp, the free moisture level of the pulp can be from about 95% to about 90% of moisture, i.e., from about 5%
to about 10% of pulp. All percentages used herein are by weight and all temperatures are in degrees Fahrenheit, unless otherwise indicated.
In accordance with the present invention, dewatered crumb pulp is utilized which contains less moisture than the free moisture level. Preferably, the dewatered crumb pulp contains from about 40% to about 95%
. - . ~ . , - ., - ' ' '~
:; ' ' ':
WO92/15754 i ~ PCT/US92/01737 2103~9 - lO -of moisture, by weight, based on the total weight. In an important embodiment of the invention, it is preferred to use dewatered crumb pulp having from about 70% to about -15% of moisture, i.e., from about 85~ to about 30% of cellulose fiber.
The process of the present invention for loading fibers is applicable to a wide range of papermaking fibers. The process can be carried out on pulps derived from many species of wood by any of the common pulping and bleaching procedures. The pulp can enter the process in a "never-dried" dewatered form or it may be reconstituted with water to a level of moisture within the indicated range from a dry state.
Cellulosic fibers of diverse natural origins may be used, including soft wood fibers, hard wood fibers, cotton fibers and fibers from bagasse, hemp and flax. The fibers may be prepared by chemical pulping, however, mechanically pulped fibers, such as ground wood, thermomechanical pulp and chemithermomechanical pulp can also be used. ~he fibers may have received some mechanical treatment, such as refining or beating prior to loading the chemical compound into the lumen.
Synthetic fibers, such as hollow filament rayon, bearing accessible internal hollow structures can also be lumen-loaded by the process of the invention.
Further in accordance with the invention,calcium oxide (lime) or calcium hydroxide is mixed with dewatered crumb pulp having the desired level of moisture. In this connection, the calcium oxide can be added to the water used for reconstituting dried fibers prior to adding the water to the fibers. Upon adding the calcium oxide to a dewatered crumb pulp and simple mixing for a period of a few minutes, the calcium oxide (as a white powder) combines with the water to form calcium hydroxide within the mass of fibers in the pulp. Since both calcium oxide and calcium hydroxide are both - , ~ .
:.
WO92/15754 2i ~ PCT/US92/01737 relatively insoluble in water (1.2 and 1.6 grams per liter, respectively) and there is no substantial free surface moisture on the fibers, the mechanism whereby the calcium oxide is drawn into the water located in the hollow fiber interior and the fiber walls is not completely understood. Calcium oxide, however, reacts vigorously with water in an exothermic reaction to produce calcium hydroxide, enough for 100 grams of quicklime to heat 200 grams of water from 0- F. to boiling. ~hile not wishing to be bound by any theory, it is believed that the calcium oxide reacts with water at the surface openings of the fiber-to form calcium hydroxide and that the calcium hydroxide is drawn into the cell walls and hollow interior of the cellulose fibers by hydrostatic forces. For this reason, the highly reactive forms of calcium oxide (quicklime) are preferably used in the process of the invention. The less reactive forms, such as dolomitic limestone and dead burned limestone are less suitable.
The calcium oxide or calcium hydroxide may be added at any desired level up to about 50%, based on the weight of the dry cellulosic material. The lower limit for addition of the calcium oxide may be as low as desired, but is preferably not less than about 0.1%.
Most preferably, the calcium oxide or calcium hydroxide is present at a level of from about 10% to about 40%, based on the weight of the dry cellulosic material. The carbon dioxide is added at a level sufficient to cause complete reaction of the chemical with the gas to form the water insoluble chemical compound. Excess gas can be used since no further reaction takes place. Since there is no extraneous chemical material formed, such as would be the case with precipitating a water-insoluble chemical compound with two water soluble salts, there is no need to wash the cellulosic material after treatment with carbon dioxide in accordance with the invention to load ..., ., , . ~ -, , , ~ -WO92/1~754 PCT/US92/01737 21~5~9 - 12 -the fibers with the precipitated calcium carbonate. In the case of paper pulp, the paper pulp can be immediately transferred to a papermaking operation where it is formed into a slurry, refined and placed onto a Fourdrinier S machine or other suitable papermaking apparatus.
Alternatively, the paper pulp having the chemical compound loaded therein may be further dried and shipped as an item of commerce to a papermaking facility for subsequent usage.
It has been determined that the precipitation of calcium carbonate in cellulosic fibers containing from about 40% to about 85% of moisture (15~ to 60% of fiber) and loaded with from about 10% to about 40% of calcium oxide or calcium hydroxide is easily effected in a pressurized container with low shear mixing. The carbon dioxide pressure in the container is preferably from about 5 psig to about 60 psig and the low shear mixing is preferably continued for a period of from about l minute to about 60 minutes.
It has also been determined that for fibers containing from about 95% to about 85% of moisture (5% to 15%) of fiber) and the same calcium oxide loading, that high shear treatment during contact with the carbon dioxide is required to cause complete precipitation of calcium carbonate. In this connection, any suitable high shear mixing device can be used. Preferably, the high shear treatment is sufficient to impart from about lO to about 70 watt hours of energy per kilo of fiber, dry weight basis.
It has been determined that a simple way to provide contact of the carbon dioxide with the paper pulp under high shear treatment is by means of a pressurized refiner. The pressurized refiner is a well known piece of apparatus utilized in the papermaking industry and consists of a cylindrical hopper into which the paper pulp is loaded. The cylindrical hopper is gas tight and ~ : - - ,. : .
...
.:. . . : -' ' ' - ' :
: ' ' 2 ~
can be pressurized with a gas. A rotating shaft containing beater arms is disposed within the hopper to keep the paper pulp from matting. An auger screw is located beneath the hopper for conveying the paper pulp into the interior space between a set of matched discs.
one of the discs is stationary whereas the opposing disk is driven by means of a motor. The discs are spaced apart by a distance sufficient to shred the pulp crumbs as the pulp passes between the stationary disk and the revolving disk. The discs may be provided with refining surfaces. The use of a "devil's tooth" plate, or fiberizing plate, has also been found to be suitable.
Prior to forcing the pulp into contact with the rotating plate, the carbon dioxide is pumped into the sealed hopper to pressurized the hopper with carbon dioxide and remains in contact with the pulp while the paper pulp is stirred in the hopper and while the pulp is being transported by the auger through the refiner discs.
It has also been determined that it is not possible to effect the reaction between the calcium oxide or calcium hydroxide and the carbon dioxide by blowing the carbon dioxide through the mixture of dewatered crumb pulp and the calcium oxide or calcium hydroxide.
Through an investigation of handsheets prepared in accordance with the invention, it has been determined that about 50% of the precipitated calcium carbonate is retained by the pulp fibers. The remaining 50% is recovered as white water which can be used to fill paper on the papermaking machine in accordance with conventional surface filling processes. The retained calcium carbonate is distributed approximately equally in the lumen, within the cell walls of the cellulose fibers and on the surface of the cellulose fibers. A higher level of retention is attained by precipitation of calcium carbonate in a pressurized container with low shear than through use of the pressurized refiner. The : - - : , , , : :
; :, . I , . , - .
W092/1~7~4 i PCT/US92/01737 210~54~` - 14 -quality of handsheets prepared from pulp wherein the ?
precipitation is effected with the pressurized refiner is, however, superior.
The following example further illustrates 5 various features of the invention, but is intended to in no way limit the scope of the invention as set forth in the appended claims.
Materials Pulp - The pulps used were a softwood pulp 10 mixture and a hardwood pulp mixture that were supplied by Consolidated Paper Company and refined further in a single disk refiner to pulp freenesses of 410 and 180 (CSF) for the softwood, and 395 and 290 (CSF) for the hardwood.
Calcium reactants - Calcium oxide used was a technical grade (Fisher Chemical Company) or a high reactivity Continental lime (Marblehead Lime Co.).
Reagent grade calcium hydroxide (Aldrich Chemical) was also used. For the direct loading comparison, papermaker 20 grade calcium carbonate (Pfizer) was used.
Equip~en~
Mixer - A bench-model 3-speed Hobart food mixer with a 20 quart stainless steel bowl and flat beater was used for mixing the calcium reactants with the pulp.
Refiner - A Sprout-Bauer pressurized disk refiner was used as both the reaction chamber and refiner ~ -for precipitating calcium carbonate and incorporating it into pulp fibers.
Filtering centrifuge - This 2-speed centrifuge is eguipped with a perforated vessel lined with a canvas bag to filter a continuous flow of low consistency slurries.
Bauer-McNett Fiber Analyzer - An industry standard method for determining non-leachable filler retention.
.
- :
' ' '' ' ' ~' ' ' ' .
.
- . . . , . :
- '- . . ' ' . : ~ . - .
:
. .
2 1 ~ 3 ~ ~ 9 PCT/US92/01737 Muffle furnace - A Thermodyne furnace was used r ashing samples.
pical Refiner Run Procedure Hobart - For each run, 1 kg pulp (based on dry weight of fiber) was blended in the Hobart mixer with - varying amounts of calcium reactant and water required for a specific chemical load and consistency. The pulp was mixed for 15 minutes at low speed (approxim~tely 110 rpm) to uniformly incorporate the calcium.
lo Refiner - The high consistency pulp was then - loaded into the hopper of the refiner which was closed and sealed. Carbon dioxide was injected into the hopper to react with the calcium hydroxide. Carbon dioxide was held in the tank at 20 lbs. pressure for 15 minutes.
During this interval, calcium carbonate was precipitated in the pulp fibers by the reaction of calcium oxide or calcium hydroxide with the carbon dioxide. The pulp is then refined in a carbon dioxide atmosphere at the desired plate gap and feed rate to provide intimate contact of the carbonate and fibers.
Direct loading - For comparisons, pulps were -loaded directly with calcium carbonate without the aid of the pressurized refiner. Pulp for direct loading was fiberized in the British Disintegrator according to Tappi 25 Standard T-205 for 60g/m2 handsheet preparation and poured into the doler tank. Varying amounts of calcium carbonate was added to the low consistency pulp slurry in the doler tank and stirred to assure uniform distribution prior to maXing handsheets.
Centrifuging - In order to avoid the high consistency mixing step using the Hobart mixer, pulps were sometimes loaded with calcium oxide or calcium hydroxide at low consistency and then dewatered. Pulp and the calcium reactant was stirred at 2% consistency with an air stirrer for 15 minutes. The pulp slurry was then fed into the filtering centrifuge to dewater the . . ', ~ ~ `
: ' ' . ....
WO92/15754 . PCT/US92/01737 21~3~4~ - 16 -pulp to approximately 30% consistency. The pulp was removed from the centrifuge bag, shredded and loaded into the pressurized refiner for reaction with carbon dioxide.
TEST ME3~LODS
Scanning Electron Microscopy (SEM) - SEM
observations and X-ray microanalysis was carried out on transverse sections of pulp fibers and handsheets.
Sections were hand-cut with a razor blade. The dry pulps and strips of handsheets (1 cm x 0.3 cm) were cemented to aluminum stubs and sputter-coated with gold. Samples were photographed in a JEOL 840 SEM at an accelerating voltage of 20 kv.
SEM X-ray microanalysis - Samples were prepared as for SEM observation, but were adhered to carbon specimen stubs and coated with a conductive carbon layer.
X-ray microanalysis was performed with a Tracor Northern T-2000/4000 energy-dispersive spectrometer in combination with the scanning electron microscope. The microanalysis spectra were recorded in an energy range of 15 keV.
The specimen preparation procedures for x-ray analysis make it necessary for controls to be employed if x-ray data are to be compared with any validity. The samples of pulp and handsheets were dried at the same time, under the same conditions. This eliminates variations arising from inconsistencies in procedures.
Once a sample is dried, care was taken to keep it free of moisture. The samples were not exposed to room air and not stored in a desiccator with chemical desiccants for fear of elemental contamination. All x-ray data to be compared was obtained with the same specimen current for biological x-ray microanalysis.
Ca~konate Test Pulp and handsheet specimens were placed in 1%
aqueous silver nitrate for 30 minutes, rinsed in distilled water and placed in 5% aqueous sodium thiosulfate for 3 minutes and washed in tap water (Van ', ' ' ',.' ~ .' . ~ ' '~, . ' .
WO92/1~754 2 1~3 ~ PCT/US92/01737 Kossa's method for carbonates). Carbonate groups (calcium) stain black. Rapid spot tests were run on samples to confirm the presence of carbonates.
Pulp/Paper Tests As each filled pulp sample was discharged from the refiner, a random sample was taken for the determination of freeness, pH and ash content. Ash content of the pulp was assessed by Tappi Method T-211.
Handsheets (60g/m2) were prepared from the pulp by standard Tappi Method T-205. Again, the ash content was determined on the handsheet, and the percent retention is reported as the percent filler in the handsheet based on the percent filler in the pulp (and subtracting the small blank of the pulp's original ash content). Percent lS retention, therefore, represents the filler retention that stays with the pulp during standard handsheet formation. Another sample of pulp from the refiner discharge was subjected to a thorough washing (20 minutes) with tap water in a chamber of a Bauer-McNett fiber fractionator and collected on a 200 mesh screen.
The ash content was determined on this Bauer-McNett --washed pulp sample, and is identified in the data tables as B/M ash%.
The handsheets were used for evaluation of burst index and for the evaluation of optical properties.
Burst index, as determined by Tappi Method T-403, is a convenient measure of strength and an accepted measure of fiber bonding. Densities of the handsheets were measured according to Tappi Method T-220 and appeared to correlate meaningfully with both freeness and burst index. Optical properties of brightness, opacity and scattering coefficient were determined on a Technidyne photometer.
Spread sheets of all the test data obtained on the pulp and handsheets are attached in the appendix.
, ... ..
- ~-, .
. -.
WO92/1~754 ~ PCT/US92/01737 2103~49 - 18 -SEM
Initial loading experiments using CaO indicated that rhombohedral calcite crystals in the 1 to 3 micron size were attained, as evidenced by electron microscopy.
Scanning electron microscopy of the cross-sections of pulp and handsheet fibers showed that calcium carbonate was precipitated as discrete angular particles, i.e., crystals. Crystalline aggregates can be seen in the lumen and on the surface. The distinctive spectrum of calcium is found within the cell-wall as well as on the fiber surface and in the cell lumen. This latter information indicates that a portion of the calcium ions can diffuse into the fiber wall as well. Calcium carbonate was confirmed to be in the lumen and on the surface of pulp and handsheet fibers.
Table 1 is a comparison of the burst and optical properties (at the same initial freeness) of refiner-run handsheets. The two numbers in parentheses, such as (15,20), indicate the pulp consistency and the calcium reactant loading, respectively. Also for comparison, are the burst and optical properties of handsheets in which the filler loading was obtained by direct addition during handsheet formation of papermaker's grade carbonate (Pfizer). The results in Table 1 are also presented in the FIGURES 1-7. If scattering coefficient, opacity or brightness are plotted versus burst index, FIGURES 1-7 points from the fiber loaded handsheets lie approximately on the same curves as the points from the direct-loaded handsheets. These plots indicate the expected inverse relationship between optical properties and strength; that is, as burst - strength increases, the desirable optical properties decreases. The fact that both fiber loaded handsheets and direct loaded handsheets of the invention lie on the same curves means that for any given gain in optical properties, one should expect a comparable loss in ~-: ' , : ,:, -, ~ , -,.............. . - - : - :
.: . . , -.
: , - : .
,' ~ , ' ~: ' ' ,, - - , , ~ , , , : , , ' '' . .: " .' . -.~ , , .
- - - WO 92t1~;75~ 21~ 3 ~ 'i 9 PCr/US92/01737 strength properties regardless of how the filler is incorporated.
T~ble 1 C~IP~RISO~I OF WRST ~IID CPTIC~- PROPERTIES
5~T~EEN F10ER ~,~pED ~ DIRECT LOADED H~IIDSNEETS
P. Sc~tt ~rightnessOp city Coeff Density aurst Index P~per Ash 9/11 Ash Type ~X) ~X~2/ltg)~ltc~m3) ~ .mVg) ~X) ~X) CTRL-al.HU~395) 87.7 78.5 47.7 717.7 3.14 0.24 --10 46X D.C~CO3 90.6 87.2 101.6 648.4 1.12 16.25 --36X D.C C03 90.3 86.2 93.0 651.6 1.26 12.35 0.35 ~ 27X D.C-C03 89.6 84.6 79.6 671.7 1.65 8.80 0.35 16X D.C-CD3 U.5 81.5 60.4 676.2 2.03 4.10 --12X D.C C03 U.l 81.5 58.2 687.2 2.23 3.02 --15 10X D.C CO3 U.6 81.5 60.3 679.2 2.12 3.83 --5X D.C-CO387.8 79.5 53.5 696.0 2.57 1.74 --Ru~ 4214 ~21,20)89.082.2 64.1 722.6 1.70 9.82 4.19 Rm ~233 ~21,20) U.8 82.5 63.9 750.8 1.92 10.U 5.34 Ru~ #243 ~21,20)U.7 82.2 62.6 741.1 1.86 9.38 3.80 20 Rvl #245 ~21,20)88.~82.4 64.0 738.5 1.81 9.51 3.30 Rv~ #275 ~21,20)88.682.2 63.1 737.1 1.78 9.16 3.34 Rv~ #265 ~21,20~U.7 83.0 66.7 727.2 1.71 10.17 3.77 R~ #213 ~18,20)88.8 82.2 64.3 736.3 1.80 10.04 3.59 Uu~ #217 ~18,30)90.0 K.5 78.9 719.2 1.27 15.39 5.22 25 Ru~ ~211 ~15,20)88.882.7 65.1 712.6 2.10 10.58 3.54 Rul #218 ~18,10)87.879.8 53.2 r20.7 2.34 5.11 2.69 FIGURE 4 is a plot of burst index versus ash content. The direct loaded handsheets lie on a smooth curve; again demonstrating that as the ash content increases, the burst strength decreases. The points from the fiber-loaded handsheets are plotted in the same figure and all of the fiber-loaded handsheets lie considerably above the direct-loaded curve. This means that at comparable ash contents, the fiber-loaded handsheets of the invention are considerably stronger.
The converse also holds true, as seen in FIGURES 5-7, when optical properties are plotted versus ash content.
At equal ash content, the direct-loaded handsheets exhibit better optical properties than the fiber-loaded handsheets of the invention.
. .
.
WO92/1~7~4 PCT/US92/01737 2103~'~9 - 20 -Conclusions It has been demonstrated that fiber loading with calcium carbonate can be accomplished by an in situ --reaction between calcium oxide (or hydroxide) and carbon dioxide in high consistency dewatered crumb pulps. A
pressurized Sprout-Bauer disk refiner adequately serves as both reaction chamber and as a means for obtaining a good dispersion of filler and fiber. SEM examination has revealed the presence of calcium carbonate crystals on both external fiber surfaces and within the cell lumen;
and x-ray microprobe analysis indicates the presence of calcium within the cell wall. Optimum conditions for fiber loading using the pressurized refiner occur at pulp consistency of 18% for softwood pulp and 21% for hardwood 15 pulp.
In some respects, handsheet properties prepared from fiber-loaded pulp outperformed direct loaded handsheets. When compared at equal filler content and equal freeness, the fiber-loaded handsheet exhibited greater bursting strength. This indicates that comparable burst strength can be obtained at higher ash content for handsheets made from fiber loaded pulp than handsheets made from direct loaded pulp. Also, at the same burst strengths, similar optical properties are obtained. This permits lower cost calcium carbonate to be substituted for higher cost fiber at no loss in burst or optical properties. This is a potential large æaving in papermaking costs.
At equal ash contents, the poorer optical -properties in comparison to the direct loaded sheets is partly understandable because the papermakers' carbonate was specifically designed in terms of crystal morphology and particle size to achieve maximum scattering power.
In addition, filler in close contact with cell-wall material (as for example inside cell lumen) may inherently scatter less because the difference in .' ~ : , ' ~ ,,.
W092/1~7~ PCT/~S92/0173/
21û3~9 refractive index between filler and cell-wall material is smaller than the difference in refractive index between filler and air.
.
. . ~. . , . : ~ ..
-.,: ' ' ' ' ` ', ' ' '' ` ' ' '' ' ' ' . , ~ ' ',, ' " ' ' ' '.: ',, ' ~ ' ' ' ' ~ .' ', ., , . : , .. : ' , ~
,' .' ,. ' , ' ':
: ' . . ' . . ` ' ,...
', : , :' ~:' ~ . ` . '.
~,' ' '; ' ' ~ ' ,' ., ' '' '''' ' ~
Claims (30)
1. A method for loading cellulosic fibers with calcium carbonate comprising:
(a) providing a cellulosic fibrous material comprising a plurality of elongated fibers having a fiber wall surrounding a hollow interior, said fibrous material having moisture present at a level sufficient to provide said cellulosic fibrous material in the form of dewatered crumb pulp;
(b) adding a chemical selected from the group consisting of calcium oxide and calcium hydroxide to said pulp in a manner such that at least some of said chemical becomes associated with the water present in said pulp;
and (c) contacting said cellulosic fibrous material with carbon dioxide while subjecting said cellulosic fibrous material to high shear mixing so as to provide a cellulosic fibrous material having a substantial amount of calcium carbonate loaded within the hollow interior and within the fiber walls of the plurality of cellulosic fibers.
(a) providing a cellulosic fibrous material comprising a plurality of elongated fibers having a fiber wall surrounding a hollow interior, said fibrous material having moisture present at a level sufficient to provide said cellulosic fibrous material in the form of dewatered crumb pulp;
(b) adding a chemical selected from the group consisting of calcium oxide and calcium hydroxide to said pulp in a manner such that at least some of said chemical becomes associated with the water present in said pulp;
and (c) contacting said cellulosic fibrous material with carbon dioxide while subjecting said cellulosic fibrous material to high shear mixing so as to provide a cellulosic fibrous material having a substantial amount of calcium carbonate loaded within the hollow interior and within the fiber walls of the plurality of cellulosic fibers.
2. A method in accordance with Claim 1 wherein the moisture content of said fibrous material is from about 40% to about 95% by weight.
3. A method in accordance with Claim 1 wherein said chemical is added at a level of from about 0.1% to about 50% by weight based on the dry weight of said fibrous material.
4. A method in accordance with Claim 1 wherein said chemical is added at a level of from about 5% to about 20% by weight based on the dry weight of said fibrous cellulose material.
5. A method in accordance with Claim 1 wherein said contact with carbon dioxide is effected in a closed container pressurized with carbon dioxide gas.
6. A method in accordance with Claim 5 wherein said carbon dioxide gas pressure is from about 5 psig to about 60 psig.
7. A method in accordance with Claim 5 wherein said carbon dioxide is maintained in contact with said pulp for a period of from about 1 minute to about 60 minutes.
8. A method in accordance with Claim 1 wherein said contact with carbon dioxide is effected while said pulp is subjected to high shear mixing.
9. A method in accordance with Claim 1 wherein said high shear mixing is sufficient to impart from about 10 to about 70 watt hours of energy per kilo of fiber, dry weight basis.
10. A paper pulp loaded with calcium carbonate wherein said calcium carbonate is partially within the lumens and the cell walls of the cellulose fibers.
11. A paper pulp in accordance with Claim 10 wherein said calcium carbonate is present at a level of from about 0.1% to abut 50% by weight on a calcium oxide basis on the dry weight of said paper pulp.
12. A paper pulp in accordance with Claim 10 wherein said calcium carbonate is present at a level of from about 5% to about 20% by weight on a calcium oxide basis on the dry weight of said paper pulp.
13. A filled paper made from the paper pulp of Claim 10.
14. A filled paper wherein the lumens and cell walls of cellulose fibers contain calcium carbonate which was formed in said lumens and cell walls by adding a chemical selected from the group consisting of calcium oxide and calcium hydroxide to dewatered crumb pulp and said chemical is contacted with carbon dioxide while subjecting said pulp to high shear mixing.
15. A filled paper in accordance with Claim 14 wherein the moisture content of said paper pulp is from about 40% to about 95% by weight.
16. A filled paper in accordance with Claim 14 wherein said chemical is added to said paper pulp at a level of from about 0.1% to about 50% by weight based on the dry weight of said paper pulp.
17. A filled paper in accordance with Claim 14 wherein said chemical is added to said paper pulp at a level of from about 5% to about 20% by weight based on the dry weight of said paper pulp.
18. A method for making a filled paper from cellulose fibers having tubular walls and lumens which contain precipitated calcium carbonate comprising:
(a) providing cellulose fibers containing water;
(b) adding a chemical selected from the group consisting of calcium hydroxide and calcium oxide to the cellulose fibers;
(c) contacting said fibers with carbon dioxide gas while subjecting said fibers to high shear mixing so that there is a reaction with the chemical to form precipitated calcium carbonate both in the interior of the fibers and in the fiber walls; and (d) forming paper from said fibers.
(a) providing cellulose fibers containing water;
(b) adding a chemical selected from the group consisting of calcium hydroxide and calcium oxide to the cellulose fibers;
(c) contacting said fibers with carbon dioxide gas while subjecting said fibers to high shear mixing so that there is a reaction with the chemical to form precipitated calcium carbonate both in the interior of the fibers and in the fiber walls; and (d) forming paper from said fibers.
19. A method in accordance with Claim 18 wherein the water is present at a level of from about 40%
to about 95% based on the dry weight of said cellulose fibers.
to about 95% based on the dry weight of said cellulose fibers.
20. A method in accordance with Claim 18 wherein said chemical is added at a level of from about 0.1% to about 50% by weight based on the dry weight of said cellulose fibers.
21. A method in accordance with Claim 18 wherein said chemical is added at a level of from about 5% to about 20% by weight based on the dry weight of said cellulose fibers.
22. A method in accordance with Claim 18 wherein said contact with carbon dioxide is effected in a closed container pressurized with carbon dioxide gas.
23. A method in accordance with Claim 22 wherein said carbon dioxide gas pressure is from about 5 psig to about 60 psig.
24. A method in accordance with Claim 22 wherein said carbon dioxide is maintained in contact with said pulp for a period of from about 10 minutes to about 60 minutes.
25. A method in accordance with Claim 22 wherein said contact with carbon dioxide is effected while said pulp is subjected to high shear mixing.
26. A method in accordance with Claim 18 wherein said high shear mixing is sufficient to impart from about 10 to about 70 watt hours of energy per kilo of fiber, dry weight basis.
27. A filled paper having precipitated calcium carbonate present in both the interior of the cellulose fibers and within the fiber walls.
28. A filled paper in accordance with Claim 27 wherein said precipitated calcium carbonate is formed by a reaction between calcium hydroxide and carbon dioxide.
29. A filled paper in accordance with Claim 27 wherein said calcium carbonate is present at a level of from about 0.1% to about 50% by weight on a calcium oxide basis based on the dry weight of said cellulose fibers.
30. A filled paper in accordance with Claim 27 wherein said calcium carbonate is present at a level of from about 5% to about 20% by weight on a calcium oxide basis based on the dry weight of said cellulose fibers.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US66546491A | 1991-03-06 | 1991-03-06 | |
| US665,464 | 1991-03-06 | ||
| US805,025 | 1991-12-11 | ||
| US07/805,025 US5223090A (en) | 1991-03-06 | 1991-12-11 | Method for fiber loading a chemical compound |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2103549A1 true CA2103549A1 (en) | 1992-09-07 |
Family
ID=27099205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002103549A Abandoned CA2103549A1 (en) | 1991-03-06 | 1992-03-05 | Method for fiber loading a chemical compound |
Country Status (21)
| Country | Link |
|---|---|
| US (2) | US5223090A (en) |
| EP (1) | EP0690938B1 (en) |
| JP (1) | JP3145707B2 (en) |
| KR (1) | KR100213456B1 (en) |
| AR (1) | AR245965A1 (en) |
| AT (1) | ATE158036T1 (en) |
| AU (1) | AU650968B2 (en) |
| BG (1) | BG98139A (en) |
| BR (1) | BR9205696A (en) |
| CA (1) | CA2103549A1 (en) |
| CZ (1) | CZ183093A3 (en) |
| DE (1) | DE69222190T2 (en) |
| ES (1) | ES2107532T3 (en) |
| FI (1) | FI933789A0 (en) |
| HU (1) | HUT67632A (en) |
| MX (1) | MX9200975A (en) |
| PL (1) | PL171323B1 (en) |
| RO (1) | RO110837B1 (en) |
| SK (1) | SK87293A3 (en) |
| UA (1) | UA27109C2 (en) |
| WO (1) | WO1992015754A1 (en) |
Families Citing this family (143)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2689530B1 (en) * | 1992-04-07 | 1996-12-13 | Aussedat Rey | NEW COMPLEX PRODUCT BASED ON FIBERS AND FILLERS, AND METHOD FOR MANUFACTURING SUCH A NEW PRODUCT. |
| SE9301220D0 (en) * | 1993-04-14 | 1993-04-14 | Kabi Pharmacia Ab | MANUFACTURING MATRICES |
| US5665205A (en) * | 1995-01-19 | 1997-09-09 | International Paper Company | Method for improving brightness and cleanliness of secondary fibers for paper and paperboard manufacture |
| US5679220A (en) * | 1995-01-19 | 1997-10-21 | International Paper Company | Process for enhanced deposition and retention of particulate filler on papermaking fibers |
| FI100729B (en) | 1995-06-29 | 1998-02-13 | Metsae Serla Oy | Filler used in papermaking and method of making the filler |
| US5759349A (en) * | 1995-12-14 | 1998-06-02 | Westvaco Corporation | Lumen loading of hygienic end use paper fibers |
| FI100670B (en) * | 1996-02-20 | 1998-01-30 | Metsae Serla Oy | Process for adding filler to cellulose fiber based m assa |
| US5786080A (en) * | 1996-04-03 | 1998-07-28 | E. Khashoggi Industries | Compositions and methods for manufacturing ettringite coated fibers and aggregates |
| US5925218A (en) * | 1997-03-03 | 1999-07-20 | Westvaco Corporation | Rehydration of once-dried fiber |
| US6579410B1 (en) * | 1997-07-14 | 2003-06-17 | Imerys Minerals Limited | Pigment materials and their preparation and use |
| US6406594B1 (en) * | 1997-07-18 | 2002-06-18 | Boise Cascade Corporation | Method for manufacturing paper products comprising polymerized mineral networks |
| US5928470A (en) * | 1997-11-07 | 1999-07-27 | Kimberly-Clark Worldwide, Inc. | Method for filling and coating cellulose fibers |
| FI103520B1 (en) * | 1998-03-03 | 1999-07-15 | Aga Ab | Improved papermaking methods |
| WO1999049133A1 (en) | 1998-03-23 | 1999-09-30 | Pulp And Paper Research Institute Of Canada | Method for producing pulp and paper with calcium carbonate filler |
| GB2337989B (en) * | 1998-05-25 | 2003-10-01 | Chisso Corp | Intermediates and improved processes for the preparation of neplanocin A |
| DE19828952B4 (en) | 1998-06-29 | 2005-04-14 | Voith Paper Patent Gmbh | Method for producing satined paper |
| US6503466B1 (en) | 1998-08-06 | 2003-01-07 | Voith Sulzer Paper Technology North America, Inc. | Apparatus and method for chemically loading fibers in a fiber suspension |
| US6210533B1 (en) | 1998-12-18 | 2001-04-03 | Voith Sulzer Paper Technology North America, Inc. | Revolver valve for discharging a pressurized vessel in a fiber stock preparation system |
| US6045656A (en) * | 1998-12-21 | 2000-04-04 | Westvaco Corporation | Process for making and detecting anti-counterfeit paper |
| US6773769B1 (en) * | 1999-05-18 | 2004-08-10 | 3M Innovative Properties Company | Macroporous ink receiving media |
| ES2318885T3 (en) | 1999-08-13 | 2009-05-01 | Georgia-Pacific France | MANUFACTURING PROCEDURE OF A PAPER SHEET THAT INCLUDES THE SETTING OF A MINERAL LOAD ON A CELLULOSICAL FIBERS. |
| US6533895B1 (en) | 2000-02-24 | 2003-03-18 | Voith Sulzer Paper Technology North America, Inc. | Apparatus and method for chemically loading fibers in a fiber suspension |
| US6355138B1 (en) | 2000-02-24 | 2002-03-12 | Voith Sulzer Paper Technology North America, Inc. | Method of chemically loading fibers in a fiber suspension |
| US6379498B1 (en) * | 2000-02-28 | 2002-04-30 | Kimberly-Clark Worldwide, Inc. | Method for adding an adsorbable chemical additive to pulp during the pulp processing and products made by said method |
| BR0109283A (en) | 2000-03-14 | 2002-12-17 | James Hardie Res Pty Ltd | Fiber cement construction materials containing low density additives |
| DE10021979A1 (en) * | 2000-05-05 | 2001-11-08 | Voith Paper Patent Gmbh | Method and device for forming a multilayer and / or multilayer fibrous web |
| EP1158088A3 (en) * | 2000-05-26 | 2003-01-22 | Voith Paper Patent GmbH | Process and device for treating a fibrous suspension |
| ATE278838T1 (en) * | 2000-06-27 | 2004-10-15 | Int Paper Co | METHOD FOR MAKING PAPER USING FIBER AND FILLER COMPLEXES |
| DE10033979A1 (en) * | 2000-07-13 | 2002-01-24 | Voith Paper Patent Gmbh | Method for loading fibers with calcium carbonate |
| DE10033978A1 (en) * | 2000-07-13 | 2002-01-24 | Voith Paper Patent Gmbh | Method and device for loading fibers with calcium carbonate |
| US6445316B1 (en) | 2000-09-29 | 2002-09-03 | Intel Corporation | Universal impedance control for wide range loaded signals |
| KR100855848B1 (en) | 2000-10-04 | 2008-09-01 | 제임스 하디 인터내셔널 파이낸스 비.브이. | Fiber cement composite materials using sized cellulose fibers |
| PL365806A1 (en) * | 2000-10-04 | 2005-01-10 | James Hardie Research Pty Limited | Fiber cement composite materials using cellulose fibers loaded with inorganic and/or organic substances |
| US20050126430A1 (en) * | 2000-10-17 | 2005-06-16 | Lightner James E.Jr. | Building materials with bioresistant properties |
| ATE337281T1 (en) * | 2000-10-17 | 2006-09-15 | James Hardie Int Finance Bv | FIBER CEMENT COMPOSITE MATERIAL WITH BIOCIDE TREATED, DURABLE CELLULOSE FIBERS |
| AU2001296904B2 (en) | 2000-10-17 | 2007-08-30 | James Hardie Technology Limited | Method and apparatus for reducing impurities in cellulose fibers for manufacture of fiber reinforced cement composite materials |
| US20040104003A1 (en) * | 2000-11-28 | 2004-06-03 | Biopulping International, Inc. | Eucalyptus biokraft pulping process |
| US6458241B1 (en) | 2001-01-08 | 2002-10-01 | Voith Paper, Inc. | Apparatus for chemically loading fibers in a fiber suspension |
| DE10107448A1 (en) * | 2001-02-16 | 2002-08-22 | Voith Paper Patent Gmbh | Method and device for loading fibers contained in a fiber suspension with a filler |
| US7749356B2 (en) | 2001-03-07 | 2010-07-06 | Kimberly-Clark Worldwide, Inc. | Method for using water insoluble chemical additives with pulp and products made by said method |
| US6582560B2 (en) | 2001-03-07 | 2003-06-24 | Kimberly-Clark Worldwide, Inc. | Method for using water insoluble chemical additives with pulp and products made by said method |
| JP4384411B2 (en) * | 2001-03-09 | 2009-12-16 | ジェイムズ ハーディー インターナショナル ファイナンス ベスローテン フェンノートシャップ | Fiber reinforced cement composites using chemically treated fibers with improved dispersibility |
| DE10113998A1 (en) * | 2001-03-22 | 2002-09-26 | Voith Paper Patent Gmbh | Method for loading fibers contained in a fiber suspension with an auxiliary |
| DE10115421A1 (en) * | 2001-03-29 | 2002-10-02 | Voith Paper Patent Gmbh | Process and preparation of pulp |
| DE10117236A1 (en) * | 2001-04-06 | 2002-10-17 | Voith Paper Patent Gmbh | Paper making process uses never-dried-pulp with additive introduced by chemical precipitation |
| FI117873B (en) * | 2001-04-24 | 2007-03-30 | M Real Oyj | Fiber web and method of making it |
| FI117870B (en) * | 2001-04-24 | 2011-06-27 | M Real Oyj | Coated fiber web and method of making it |
| FI117872B (en) * | 2001-04-24 | 2007-03-30 | M Real Oyj | Fillers and process for their preparation |
| FI117871B (en) * | 2001-04-24 | 2007-03-30 | M Real Oyj | Multilayer fiber product and process for its preparation |
| DE10120526A1 (en) * | 2001-04-26 | 2002-10-31 | Voith Paper Patent Gmbh | Process for the production of pulp |
| DE10120637A1 (en) * | 2001-04-27 | 2002-10-31 | Voith Paper Patent Gmbh | Process for loading fibers |
| DE10120636A1 (en) * | 2001-04-27 | 2002-10-31 | Voith Paper Patent Gmbh | Method and device for the preparation of material used in particular for papermaking |
| DE10120635A1 (en) * | 2001-04-27 | 2002-10-31 | Voith Paper Patent Gmbh | Method and device for loading fibers with calcium carbonate |
| NZ530337A (en) * | 2001-06-01 | 2005-08-26 | Biopulping Int Inc | Process fro making wood pulp from eucalyptus using the white rot fungus Ceriporiopsis subvermispora followed by mechanical pulping |
| US6673211B2 (en) | 2001-07-11 | 2004-01-06 | Voith Paper Patent Gmbh | Apparatus for loading fibers in a fiber suspension with calcium carbonate |
| US6413365B1 (en) | 2001-07-11 | 2002-07-02 | Voith Paper Patent Gmbh | Method of loading a fiber suspension with calcium carbonate |
| US20030094252A1 (en) * | 2001-10-17 | 2003-05-22 | American Air Liquide, Inc. | Cellulosic products containing improved percentage of calcium carbonate filler in the presence of other papermaking additives |
| CA2466505A1 (en) * | 2001-11-09 | 2003-05-15 | Biopulping International, Inc. | Microwave pre-treatment of logs for use in making paper and other wood products |
| DE10204254A1 (en) * | 2002-02-02 | 2003-08-14 | Voith Paper Patent Gmbh | Online production of crystalline precipitation particles in fiber suspension processes is preferably effected using precipitated calcium carbonate |
| DE10204255A1 (en) * | 2002-02-02 | 2003-08-07 | Voith Paper Patent Gmbh | Loading fiber and/or coating slip suspensions for papermaking involves addition of precipitate followed by milling |
| CN100363554C (en) * | 2002-02-02 | 2008-01-23 | 沃伊斯造纸专利有限公同 | Method for preparing fibres contained in a pulp suspension |
| DE10208983A1 (en) * | 2002-02-28 | 2003-09-11 | Voith Paper Patent Gmbh | Process for producing a fibrous web |
| US20050121157A1 (en) * | 2002-02-28 | 2005-06-09 | Klaus Doelle | Method for the fabrication of a fiber web |
| JP4000949B2 (en) * | 2002-08-08 | 2007-10-31 | 株式会社アドヴィックス | Wedge-operated brake device |
| US6942726B2 (en) * | 2002-08-23 | 2005-09-13 | Bki Holding Corporation | Cementitious material reinforced with chemically treated cellulose fiber |
| US20040050515A1 (en) * | 2002-09-13 | 2004-03-18 | Klaus Doelle | Method for the production of a fiber web |
| US7993570B2 (en) | 2002-10-07 | 2011-08-09 | James Hardie Technology Limited | Durable medium-density fibre cement composite |
| US20040108081A1 (en) * | 2002-12-09 | 2004-06-10 | Specialty Minerals (Michigan) Inc. | Filler-fiber composite |
| US20040108083A1 (en) * | 2002-12-09 | 2004-06-10 | Specialty Minerals (Michigan) Inc. | Filler-fiber composite |
| EP1587767B1 (en) | 2003-01-09 | 2017-07-19 | James Hardie Technology Limited | Fiber cement composite materials using bleached cellulose fibers and their manufacturing method |
| DE10302783A1 (en) * | 2003-01-24 | 2004-08-12 | Voith Paper Patent Gmbh | Process for producing a fiber suspension intended for the production of a tissue or hygiene web |
| FI120463B (en) * | 2003-07-15 | 2009-10-30 | Upm Kymmene Corp | Method of making paper and paper |
| FI119563B (en) | 2003-07-15 | 2008-12-31 | Fp Pigments Oy | Process and apparatus for the pre-processing of fibrous materials for the production of paper, paperboard or other equivalent |
| DE10335751A1 (en) * | 2003-08-05 | 2005-03-03 | Voith Paper Patent Gmbh | Method for loading a pulp suspension and arrangement for carrying out the method |
| JP4716989B2 (en) * | 2003-08-29 | 2011-07-06 | ビーケイアイ・ホールディング・コーポレーション | Fiber foam for feeding into concrete |
| EP1518961A1 (en) * | 2003-09-23 | 2005-03-30 | Voith Paper Patent GmbH | Method for the production of a fiber web |
| DE10351292A1 (en) * | 2003-10-31 | 2006-02-02 | Voith Paper Patent Gmbh | Method for loading a pulp suspension and arrangement for carrying out the method |
| DE10357437A1 (en) * | 2003-12-09 | 2005-07-07 | Voith Paper Patent Gmbh | Method for loading a pulp suspension and arrangement for carrying out the method |
| US7479578B2 (en) * | 2003-12-19 | 2009-01-20 | Kimberly-Clark Worldwide, Inc. | Highly wettable—highly flexible fluff fibers and disposable absorbent products made of those |
| US7186318B2 (en) * | 2003-12-19 | 2007-03-06 | Kimberly-Clark Worldwide, Inc. | Soft tissue hydrophilic tissue products containing polysiloxane and having unique absorbent properties |
| US7147752B2 (en) | 2003-12-19 | 2006-12-12 | Kimberly-Clark Worldwide, Inc. | Hydrophilic fibers containing substantive polysiloxanes and tissue products made therefrom |
| US7811948B2 (en) * | 2003-12-19 | 2010-10-12 | Kimberly-Clark Worldwide, Inc. | Tissue sheets containing multiple polysiloxanes and having regions of varying hydrophobicity |
| US20050152621A1 (en) * | 2004-01-09 | 2005-07-14 | Healy Paul T. | Computer mounted file folder apparatus |
| US7220001B2 (en) * | 2004-02-24 | 2007-05-22 | Searete, Llc | Defect correction based on “virtual” lenslets |
| US20050215146A1 (en) * | 2004-03-24 | 2005-09-29 | Kimberly-Clark Worldwide, Inc. | Wiping products containing deliquescent materials |
| DE102004028047A1 (en) * | 2004-06-09 | 2005-12-29 | Voith Paper Patent Gmbh | Method and machine for producing a fibrous web |
| GB0413068D0 (en) * | 2004-06-11 | 2004-07-14 | Imerys Minerals Ltd | Treatment of pulp |
| US7998571B2 (en) | 2004-07-09 | 2011-08-16 | James Hardie Technology Limited | Composite cement article incorporating a powder coating and methods of making same |
| CA2572630A1 (en) * | 2004-07-14 | 2006-02-23 | International Paper Company | Method to manufacture paper |
| DE102004045089A1 (en) * | 2004-09-17 | 2006-03-23 | Voith Paper Patent Gmbh | Method and device for loading a pulp suspension |
| DE102004060405A1 (en) * | 2004-12-14 | 2006-07-06 | Voith Paper Patent Gmbh | Method and device for loading suspension-containing fibers or pulp with a filler |
| US7638016B2 (en) * | 2005-02-19 | 2009-12-29 | International Paper Company | Method for treating kraft pulp with optical brighteners after chlorine bleaching to increase brightness |
| DE102005012168A1 (en) * | 2005-03-17 | 2006-09-28 | Voith Paper Patent Gmbh | Method and device for loading fibers contained in a pulp suspension with filler |
| FI121311B (en) * | 2005-05-03 | 2010-09-30 | M Real Oyj | A process for the preparation of a mechanical pulp for use in the manufacture of paper and board |
| FI20055380L (en) * | 2005-07-01 | 2007-01-02 | M Real Oyj | Method for coating cellulose particles, coated cellulose particles and their use in paper and cardboard manufacturing |
| CA2614813A1 (en) * | 2005-07-12 | 2007-01-18 | Voith Patent Gmbh | Method for loading fibers contained in a pulp suspension |
| DE102006012835B3 (en) * | 2006-03-21 | 2007-11-15 | Voith Patent Gmbh | Process for the treatment of pulp containing disruptive vascular cells |
| MX2008013202A (en) | 2006-04-12 | 2009-01-09 | James Hardie Int Finance Bv | A surface sealed reinforced building element. |
| US7967948B2 (en) * | 2006-06-02 | 2011-06-28 | International Paper Company | Process for non-chlorine oxidative bleaching of mechanical pulp in the presence of optical brightening agents |
| DE102006029642B3 (en) * | 2006-06-28 | 2008-02-28 | Voith Patent Gmbh | Method for loading a pulp suspension with filler |
| KR101174952B1 (en) | 2006-07-24 | 2012-08-17 | 가부시끼가이샤 도꾸야마 | Print sheet |
| JP2008100877A (en) * | 2006-10-19 | 2008-05-01 | Nichiha Corp | Inorganic board and its manufacturing method |
| JP5069911B2 (en) * | 2007-01-12 | 2012-11-07 | ニチハ株式会社 | Bearing material and manufacturing method thereof |
| DE102007007295A1 (en) | 2007-02-14 | 2008-08-21 | Voith Patent Gmbh | Process for forming fillers, especially calcium carbonate in a pulp suspension |
| DE102007011796A1 (en) | 2007-03-12 | 2008-09-18 | Voith Patent Gmbh | Process for the treatment of loaded fibers |
| DE102007018240A1 (en) | 2007-04-18 | 2008-10-23 | Voith Patent Gmbh | Process for the formation of calcium carbonate in a pulp suspension |
| DE102007018726A1 (en) | 2007-04-20 | 2008-10-23 | Voith Patent Gmbh | Process for forming fillers, especially calcium carbonate in a pulp suspension |
| DE102007020324A1 (en) * | 2007-04-30 | 2008-11-06 | Voith Patent Gmbh | Process for the formation of calcium carbonate in a pulp suspension |
| DE102007028540A1 (en) | 2007-06-21 | 2008-12-24 | Voith Patent Gmbh | Process for forming fillers, especially calcium carbonate in a pulp suspension |
| DE102007028539A1 (en) * | 2007-06-21 | 2008-12-24 | Voith Patent Gmbh | Process for forming calcium carbonate in a pulp suspension |
| DE102007029688A1 (en) * | 2007-06-27 | 2009-01-02 | Voith Patent Gmbh | Process for forming fillers, in particular calcium carbonate in a suspension |
| DE102007029686A1 (en) | 2007-06-27 | 2009-01-02 | Voith Patent Gmbh | Process for forming calcium carbonate in a pulp suspension |
| US7758934B2 (en) | 2007-07-13 | 2010-07-20 | Georgia-Pacific Consumer Products Lp | Dual mode ink jet paper |
| DE102007051664A1 (en) | 2007-10-30 | 2009-05-07 | Voith Patent Gmbh | Process for the formation of calcium carbonate in a pulp suspension II |
| DE102007051665A1 (en) | 2007-10-30 | 2009-05-07 | Voith Patent Gmbh | Process for the formation of calcium carbonate in a pulp suspension |
| US8209927B2 (en) | 2007-12-20 | 2012-07-03 | James Hardie Technology Limited | Structural fiber cement building materials |
| US8808503B2 (en) * | 2009-02-02 | 2014-08-19 | John Klungness | Fiber loading improvements in papermaking |
| HUE035151T2 (en) | 2009-03-30 | 2018-05-02 | Fiberlean Tech Ltd | Process for the production of nano-fibrillar cellulose gels |
| EP4105380A1 (en) | 2009-03-30 | 2022-12-21 | FiberLean Technologies Limited | Process for the production of nanofibrillar cellulose suspensions |
| GB0908401D0 (en) | 2009-05-15 | 2009-06-24 | Imerys Minerals Ltd | Paper filler composition |
| FI124831B (en) * | 2010-03-10 | 2015-02-13 | Upm Kymmene Oyj | Process and reactor for in-line production of calcium carbonate in a pulp flow |
| PL2386683T3 (en) | 2010-04-27 | 2014-08-29 | Omya Int Ag | Process for the production of gel-based composite materials |
| ES2467694T3 (en) | 2010-04-27 | 2014-06-12 | Omya Development Ag | Process for manufacturing structured materials using nanofibrillar cellulose gels |
| FI125826B (en) | 2010-08-04 | 2016-02-29 | Nordkalk Oy Ab | Process for the production of paper or board |
| FI125278B (en) * | 2010-08-20 | 2015-08-14 | Upm Kymmene Corp | Process for precipitating calcium carbonate and using the process |
| GB201019288D0 (en) | 2010-11-15 | 2010-12-29 | Imerys Minerals Ltd | Compositions |
| FI124859B (en) * | 2011-06-21 | 2015-02-27 | Upm Kymmene Corp | A printing paper product and a method and system for producing a printing paper product |
| US20130168893A1 (en) * | 2011-12-29 | 2013-07-04 | Hollingsworth & Vose Company | Charging of filter media |
| RU2504609C1 (en) * | 2012-06-21 | 2014-01-20 | Леонид Асхатович Мазитов | Method of producing composite material |
| FI126072B (en) | 2013-03-18 | 2016-06-15 | Linde Ag | Fiber filling method |
| KR101510313B1 (en) * | 2013-08-21 | 2015-04-10 | 충남대학교산학협력단 | Preparation method of filler and the paper containing the filler thereby |
| SE538770C2 (en) * | 2014-05-08 | 2016-11-15 | Stora Enso Oyj | Process for making a thermoplastic fiber composite material and a fabric |
| KR101535522B1 (en) * | 2014-07-09 | 2015-07-10 | 충남대학교산학협력단 | Preparation method of filler containing cellulose and the paper containing the filler thereby |
| CN104818641B (en) * | 2015-05-08 | 2017-08-25 | 大唐国际发电股份有限公司高铝煤炭资源开发利用研发中心 | It is a kind of that the method that fiber discongests mashing is carried out based on flyash desiliconization liquid |
| BR112018007115B1 (en) | 2015-10-14 | 2022-06-14 | Fiberlean Technologies Limited | 3D-FORMABLE SHEET MATERIAL, PROCESSES FOR PREPARING A 3D-FORMED ARTICLE, ITS USES AND 3D-FORMED ARTICLE |
| SE540790C2 (en) * | 2016-02-12 | 2018-11-13 | Stora Enso Oyj | Calcium carbonate precipitated on natural fibers and method for the production thereof |
| US11846072B2 (en) | 2016-04-05 | 2023-12-19 | Fiberlean Technologies Limited | Process of making paper and paperboard products |
| DK3828339T3 (en) | 2016-04-05 | 2024-01-02 | Fiberlean Tech Ltd | PAPER AND CARDBOARD PRODUCTS |
| KR102255179B1 (en) | 2016-04-22 | 2021-05-24 | 파이버린 테크놀로지스 리미티드 | Compositions comprising microfibrilated cellulose and polymers and methods of manufacturing fibres and nonwoven materials therefrom |
| US10487452B1 (en) * | 2017-01-26 | 2019-11-26 | Kimberly-Clark Worldwide, Inc. | Treated fibers and fibrous structures comprising the same |
| WO2018180699A1 (en) * | 2017-03-31 | 2018-10-04 | 日本製紙株式会社 | Method for manufacturing inorganic particle composite fiber sheet |
| JP6855904B2 (en) * | 2017-04-24 | 2021-04-07 | セイコーエプソン株式会社 | Processing equipment and sheet manufacturing equipment |
| WO2021252572A1 (en) * | 2020-06-12 | 2021-12-16 | Specialty Minerals (Michigan) Inc. | Surface mineralized organic fibers and methods of making the same |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62162098A (en) * | 1985-12-29 | 1987-07-17 | 北越製紙株式会社 | Production of neutral paper |
| JPS62199898A (en) * | 1986-02-20 | 1987-09-03 | 北越製紙株式会社 | Production of neutral paper |
| US5096539A (en) * | 1989-07-24 | 1992-03-17 | The Board Of Regents Of The University Of Washington | Cell wall loading of never-dried pulp fibers |
| CA2063567C (en) * | 1989-07-24 | 2000-12-26 | G. Graham Allan | Cell wall loading of never-dried pulp fibers |
| DE69131108T2 (en) * | 1990-05-14 | 1999-11-25 | Oji Paper Co | Process for modifying water-absorbent fibers with a practically water-insoluble inorganic compound |
-
1991
- 1991-12-11 US US07/805,025 patent/US5223090A/en not_active Ceased
-
1992
- 1992-03-05 AT AT92908104T patent/ATE158036T1/en not_active IP Right Cessation
- 1992-03-05 HU HU9302500A patent/HUT67632A/en unknown
- 1992-03-05 WO PCT/US1992/001737 patent/WO1992015754A1/en not_active Application Discontinuation
- 1992-03-05 DE DE69222190T patent/DE69222190T2/en not_active Expired - Fee Related
- 1992-03-05 CZ CS931830A patent/CZ183093A3/en unknown
- 1992-03-05 SK SK872-93A patent/SK87293A3/en unknown
- 1992-03-05 MX MX9200975A patent/MX9200975A/en unknown
- 1992-03-05 UA UA93004133A patent/UA27109C2/en unknown
- 1992-03-05 AU AU15845/92A patent/AU650968B2/en not_active Ceased
- 1992-03-05 AR AR92321876A patent/AR245965A1/en active
- 1992-03-05 CA CA002103549A patent/CA2103549A1/en not_active Abandoned
- 1992-03-05 RO RO93-01190A patent/RO110837B1/en unknown
- 1992-03-05 JP JP50826292A patent/JP3145707B2/en not_active Expired - Fee Related
- 1992-03-05 ES ES92908104T patent/ES2107532T3/en not_active Expired - Lifetime
- 1992-03-05 PL PL92300491A patent/PL171323B1/en unknown
- 1992-03-05 BR BR9205696A patent/BR9205696A/en not_active Application Discontinuation
- 1992-03-05 EP EP92908104A patent/EP0690938B1/en not_active Expired - Lifetime
- 1992-03-05 KR KR1019930702648A patent/KR100213456B1/en not_active IP Right Cessation
-
1993
- 1993-08-30 FI FI933789A patent/FI933789A0/en unknown
- 1993-10-05 BG BG98139A patent/BG98139A/en unknown
- 1993-10-21 US US08/141,181 patent/USRE35460E/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| HUT67632A (en) | 1995-04-28 |
| SK87293A3 (en) | 1994-04-06 |
| AR245965A1 (en) | 1994-03-30 |
| RO110837B1 (en) | 1996-04-30 |
| US5223090A (en) | 1993-06-29 |
| ATE158036T1 (en) | 1997-09-15 |
| AU650968B2 (en) | 1994-07-07 |
| AU1584592A (en) | 1992-10-06 |
| JPH06507944A (en) | 1994-09-08 |
| MX9200975A (en) | 1992-09-01 |
| USRE35460E (en) | 1997-02-25 |
| EP0690938A1 (en) | 1996-01-10 |
| WO1992015754A1 (en) | 1992-09-17 |
| PL171323B1 (en) | 1997-04-30 |
| JP3145707B2 (en) | 2001-03-12 |
| FI933789A (en) | 1993-08-30 |
| BR9205696A (en) | 1994-05-24 |
| UA27109C2 (en) | 2000-02-28 |
| CZ183093A3 (en) | 1994-04-13 |
| DE69222190D1 (en) | 1997-10-16 |
| EP0690938B1 (en) | 1997-09-10 |
| KR100213456B1 (en) | 1999-08-02 |
| EP0690938A4 (en) | 1994-03-17 |
| BG98139A (en) | 1994-06-30 |
| ES2107532T3 (en) | 1997-12-01 |
| HU9302500D0 (en) | 1994-03-28 |
| DE69222190T2 (en) | 1998-02-26 |
| FI933789A0 (en) | 1993-08-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5223090A (en) | Method for fiber loading a chemical compound | |
| US10982387B2 (en) | Process for the production of nano-fibrillar cellulose suspensions | |
| JP6516854B2 (en) | Composite of cellulose fiber and inorganic particles | |
| EP0403849B1 (en) | High opacity paper containing expanded fiber and mineral pigment | |
| FI68282B (en) | PAPER MUSHROOMS VARI FIBRERNAS SNOW INNEHAOLLER FYLLMEDEL FRAMSTAELLNING OCH ANVAENDNING AV DENNA | |
| US6958108B1 (en) | Method of producing a fiber product having a strength suitable for printing paper and packaging material | |
| EP3604671B1 (en) | Method for manufacturing inorganic particle composite fiber sheet | |
| EP1165889A1 (en) | Method for increasing filler retention of cellulosic fiber sheets | |
| Klungness et al. | Lightweight, high-opacity paper by fiber loading: Filler comparison | |
| KR20120094393A (en) | Method for manufacturing lignocellulosic fillers for papermaking and the lignocellulosic fillers prepared thereby | |
| RU2098534C1 (en) | Method of filling cellulose fibers with calcium carbonate, compounded paper containing cellulose fiber mass, and method of manufacturing thereof | |
| Klungness et al. | Lightweight, High Opacity Paper: Process Costs and Energy Use Reduction | |
| Laukala | Controlling particle morphology in the in-situ formation of precipitated calcium carbonate-fiber composites | |
| JP2024051717A (en) | X-ray contrast material containing composite fiber of inorganic particles and fiber | |
| Klungness et al. | Novel lightweight, high-opacity papers made from mechanical pulps | |
| Dimic-Misic et al. | The effect of micro and nanofibrillated cellulose water uptake on high filler content composite paper properties and furnish dewatering |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |