WO1997023265A1 - High efficiency dust sock - Google Patents
High efficiency dust sock Download PDFInfo
- Publication number
- WO1997023265A1 WO1997023265A1 PCT/US1996/019851 US9619851W WO9723265A1 WO 1997023265 A1 WO1997023265 A1 WO 1997023265A1 US 9619851 W US9619851 W US 9619851W WO 9723265 A1 WO9723265 A1 WO 9723265A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- filter medium
- laminate
- dust
- dust sock
- medium laminate
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
- B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
- B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/08—Filter cloth, i.e. woven, knitted or interlaced material
- B01D39/083—Filter cloth, i.e. woven, knitted or interlaced material of organic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/02—Particle separators, e.g. dust precipitators, having hollow filters made of flexible material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/022—Non-woven fabric
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/08—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer the fibres or filaments of a layer being of different substances, e.g. conjugate fibres, mixture of different fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
- B01D2239/0216—Bicomponent or multicomponent fibres
- B01D2239/0225—Side-by-side
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
- B01D2239/0216—Bicomponent or multicomponent fibres
- B01D2239/0233—Island-in-sea
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/04—Additives and treatments of the filtering material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/04—Additives and treatments of the filtering material
- B01D2239/0407—Additives and treatments of the filtering material comprising particulate additives, e.g. adsorbents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/04—Additives and treatments of the filtering material
- B01D2239/0457—Specific fire retardant or heat resistant properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
- B01D2239/0604—Arrangement of the fibres in the filtering material
- B01D2239/0622—Melt-blown
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
- B01D2239/0604—Arrangement of the fibres in the filtering material
- B01D2239/0627—Spun-bonded
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
- B01D2239/065—More than one layer present in the filtering material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
- B01D2239/065—More than one layer present in the filtering material
- B01D2239/0654—Support layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
- B01D2239/065—More than one layer present in the filtering material
- B01D2239/0668—The layers being joined by heat or melt-bonding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/10—Filtering material manufacturing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/1233—Fibre diameter
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
- B01D2239/12—Special parameters characterising the filtering material
- B01D2239/1291—Other parameters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
- B29K2105/08—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns
- B29K2105/0854—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of continuous length, e.g. cords, rovings, mats, fabrics, strands or yarns in the form of a non-woven mat
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/02—Synthetic macromolecular fibres
- B32B2262/0253—Polyolefin fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/12—Conjugate fibres, e.g. core/sheath or side-by-side
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/40—Properties of the layers or laminate having particular optical properties
- B32B2307/42—Polarizing, birefringent, filtering
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/903—Microfiber, less than 100 micron diameter
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S55/00—Gas separation
- Y10S55/05—Methods of making filter
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
- Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
- Y10T428/1362—Textile, fabric, cloth, or pile containing [e.g., web, net, woven, knitted, mesh, nonwoven, matted, etc.]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
- Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
- Y10T442/608—Including strand or fiber material which is of specific structural definition
- Y10T442/614—Strand or fiber material specified as having microdimensions [i.e., microfiber]
- Y10T442/622—Microfiber is a composite fiber
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
- Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
- Y10T442/637—Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
- Y10T442/638—Side-by-side multicomponent strand or fiber material
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
- Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
- Y10T442/637—Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material
- Y10T442/641—Sheath-core multicomponent strand or fiber material
Definitions
- This invention relates generally to a nonwoven fabric or web which is formed from spunbond fibers of a thermoplastic resin, and laminates using such a web as a component.
- the fabric is used as a filter, particularly for industrial applications where the fabric is in the form of a sock.
- thermoplastic resins have been extruded to form fibers, fabrics and webs for a number of years.
- the most common thermoplastics for this application are polyolefins, particularly polypropylene.
- Other materials such as polyesters, polyetheresters, polyamides and polyurethanes are also used to form nonwoven spunbond fabrics.
- Nonwoven fabrics or webs are useful for a wide variety of applications such as diapers, feminine hygiene products, towels, recreational or protective fabrics and as geotextiles and filter media.
- the nonwoven webs used in these applications may be simply spunbond fabrics but are often in the form of nonwoven fabric laminates like spunbond/spunbond (SS) laminates or spunbond/meltblown/spunbond (SMS) laminates.
- SS spunbond/spunbond
- SMS spunbond/meltblown/spunbond
- High filtration efficiency is, of course, the main purpose for a filter and great efficiency and ability to maintain the efficiency at an acceptable level are key to filter performance.
- a dust sock filter medium laminate which has at least two nonwoven webs of microfibers which have an average diameter (using a sample size of at least 10) between about 10 and 25 microns and which webs have been joined by a method comprising the steps of (a) directing the component layers to a separation zone, (b) applying water in the amount of from about 5% to 25% based on the weight of the combined layers, (c) combining the component layers, (d) passing the combination through a sonic bonder operating within the range of up to about 40,000 cps against a patterned anvil to produce a corresponding pattern of thermal bond areas over about 3% to 25% of the surface area of the combination, and, (e) drying the sonically bonded combination. While this invention is directed mainly to air filtration, other gasses may be filtered as well.
- the dust socks of this invention desirably have a basis weight between about 85 and 205 gsm, a Frazier permeability of above 100
- the Figure is a schematic drawing of a dust sock attached to a fan.
- nonwoven fabric or web means a web having a structure of individual fibers or threads which are interlaid, but not in an identifiable manner as in a knitted fabric.
- Nonwoven fabrics or webs have been formed from many processes such as, for example, meltblowing processes, spunbonding processes, and bonded carded web processes.
- the basis weight of nonwoven fabrics is usually expressed in ounces of material per square yard (osy) or grams per square meter (gsm) and the fiber diameters useful are usually expressed in microns. (Note that to convert from osy to gsm, multiply osy by 33.91).
- microfibers means small diameter fibers having an average diameter not greater than about 75 microns, for example, having an average diameter of from about 0.5 microns to about 50 microns, or more particularly, microfibers may have an average diameter of from about 2 microns to about 40 microns.
- denier is defined as grams per 9000 meters of a fiber and may be calculated as fiber diameter in microns squared, multiplied by the density in grams/cc, multiplied by 0.00707. A lower denier indicates a finer fiber and a higher denier indicates a thicker or heavier fiber.
- the diameter of a polypropylene fiber given as 15 microns may be converted to denier by squaring, multiplying the result by .89 g/cc and multiplying by .00707.
- spunbonded fibers refers to small diameter fibers which are formed by extruding molten thermoplastic material as filaments from a plurality of fine, usually circular capillaries of a spinneret with the diameter of the extruded filaments then being rapidly reduced as by, for example, in U.S. Patent no. 4,340,563 to Appel et al., and U.S. Patent no. 3,692,618 to Dorschner et al., U.S. Patent no. 3,802,817 to Matsuki et al., U.S. Patent nos. 3,338,992 and 3,341,394 to Kinney, U.S. Patent no. 3,502,763 to Hartman, and U.S. Patent no.
- Spunbond fibers are generally not tacky when they are deposited onto a collecting surface. Spunbond fibers are generally continuous and have average diameters (using a sample size of at least 10) larger than 7 microns, more particularly, between about 10 and 25 microns.
- meltblown fibers means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into converging high velocity, usually hot, gas (e.g. air) streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed meltblown fibers.
- gas e.g. air
- conjugate fibers refers to fibers which have been formed from at least two polymers extruded from separate extruders but spun together to form one fiber. Conjugate fibers are also sometimes referred to as multicomponent or bicomponent fibers.
- the polymers are usually different from each other though conjugate fibers may be monocomponent fibers.
- the polymers are arranged in substantially constantly positioned distinct zones across the cross- section of the conjugate fibers and extend continuously along the length of the conjugate fibers.
- the configuration of such a conjugate fiber may be, for example, a sheath/core arrangement wherein one polymer is surrounded by another or may be a side by side arrangement, a segmented configuration or an "islands-in-the-sea" arrangement.
- Conjugate fibers are taught in U.S. Patent 5,108,820 to Kaneko et al., U.S. Patent 5,336,552 to Strack et al., and U.S. Patent 5,382,400 to Pike et al.
- the polymers may be present in ratios of 75/25, 50/50, 25/75 or any other desired ratios.
- thermal point bonding involves passing a fabric or web of fibers to be bonded between a heated calender roll and an anvil roll.
- the calender roll is usually, though not always, patterned in some way so that the entire fabric is not bonded across its entire surface and the anvil is usually flat.
- various patterns for calender rolls have been developed for functional as well as aesthetic reasons.
- One example of a pattern is the Hansen Pennings or "H&P" pattern with between about a 5 and 50% bond area with between about 50-3200 bonds/square inch as taught in U.S. Patent 3,855,046 to Hansen and Pennings.
- H&P pattern has square point or pin bonding areas wherein each pin has a side dimension of 0.038 inches (0.965 mm), a spacing of 0.070 inches (1.778 mm) between pins, and a depth of bonding of 0.023 inches (0.584 mm).
- Another typical point bonding pattern is the expanded Hansen Pennings or "EHP" bond pattern which produces about a 15% bond area with a square pin having a side dimension of 0.037 inches (0.94 mm), a pin spacing of 0.097 inches (2.464 mm) and a depth of 0.039 inches (0.991 mm).
- Another typical point bonding pattern designated “714" has square pin bonding areas wherein each pin has a side dimension of 0.023 inches, a spacing of 0.062 inches (1.575 mm) between pins, and a depth of bonding of 0.033 inches (0.838 mm). The resulting pattern has a bonded area of about 15%.
- Yet another common pattern is the C-Star pattern which has a bond area of about 16.9%.
- the C-Star pattem has a cross-directional bar or "corduroy" design interrupted by shooting stars.
- Other common patterns include a diamond pattem with repeating and slightly offset diamonds and a wire weave pattem looking as the name suggests, e.g. like a window screen.
- the percent bonding area varies from around 10% to around 30% of the area of the fabric laminate web.
- the spot bonding holds the laminate layers together as well as imparts integrity to each individual layer by bonding filaments and/or fibers within each layer.
- ultrasonic bonding means a process performed, for example, by passing the fabric between a sonic horn and anvil roll as illustrated in U.S. Patent 4,374,888 to Bomslaeger.
- Frazier Permeability A measure of the permeability of a fabric or web to air is the Frazier Permeability which is performed according to Federal Test Standard No. 191 A, Method 5450 dated July 20, 1978, and is reported as an average of 3 sample readings. Frazier Permeability measures the air flow rate through a web in cubic feet of air per minute per square foot of web or CFM/SF. Convert CFM/SF to liters per square meter per minute (LSM) by multiplying CFM/SF by 304.8.
- LSM liters per square meter per minute
- NaCl Efficiency is a measure of the ability of a fabric or web to stop the passage of small particles through it. A higher efficiency is generally more desirable and indicates a greater ability to remove particles. NaCl efficiency is measured in percent according to the TSI Inc., Model 8110 Automated Filter Tester Operation Manual of February 1993, P/N 1980053, revision D, at a flow rate of 32 liters per minute using 0.1 micron sized NaCl particles and is reported as an average of 3 sample readings. The manual is available from TSI Inc. at PO Box 64394, 500 Cardigan Rd, St. Paul, MN 55164. This test also can yield a pressure differential across a fabric using the same particle size and airflow rate.
- the melt flow rate is a measure of the viscosity of a polymer.
- the MFR is expressed as the weight of material which flows from a capillary of known dimensions under a specified load or shear rate for a measured period of time and is measured in grams/10 minutes at a set temperature and load according to, for example, ASTM test 1238-90b.
- the spunbond process generally uses a hopper which supplies polymer to a heated extruder.
- the extruder supplies melted polymer to a spinneret where the polymer is fiberized as it passes through fine openings arranged in one or more rows in the spinneret, forming a curtain of filaments.
- the filaments are usually quenched with air at a low pressure, drawn, usually pneumatically and deposited on a moving foraminous mat, belt or "forming wire” to form the nonwoven web.
- Polymers useful in the spunbond process generally have a process melt temperature of between about 400°F to about 610°F (200°C to 320 ⁇ C).
- the fibers produced in the spunbond process are usually in the range of from about 10 to about 50 microns in average diameter, depending on process conditions and the desired end use for the webs to be produced from such fibers. For example, increasing the polymer molecular weight or decreasing the processing temperature results in larger diameter fibers. Changes in the quench fluid temperature and pneumatic draw pressure can also affect fiber diameter.
- the fibers used in the practice of this invention usually have average diameters in the range of from about 7 to about 35 microns, more particularly from about 15 to about 25 microns.
- the fabric of this invention may be a multilayer laminate and may be formed by a number of different techniques including but not limited to using adhesive, needle punching, ultrasonic bonding, thermal calendering and any other method known in the art.
- a multilayer laminate may be an embodiment wherein some of the layers are spunbond and some meltblown such as a spunbond/meltblown/spunbond (SMS) laminate as disclosed in U.S. Patent no. 4,041,203 to Brock et al. and U.S. Patent no. 5,169,706 to Collier, et al. or as a spunbond/spunbond laminate.
- SMS spunbond/meltblown/spunbond
- An SMS laminate may be made by sequentially depositing onto a moving conveyor belt or forming wire first a spunbond web layer, then a meltblown web layer and last another spunbond layer and then bonding the laminate in a manner described above. Altematively, the three web layers may be made individually, collected in rolls, and combined in a separate bonding step.
- the fabric may also be a laminate of spunbond fabric and scrim materials. Scrim materials provide little mass and essentially no filtration ability but do provide an additional degree of intregrity or strength to the fabric. Scrims usually are fibers bonded together to produce a square pattem which is quite large, e.g. as much as 5 inches (127mm) by 5 inches, though the pattem need not be exactly square. Scrims may be, for example, 3 inches (76mm) by 2 inches (51mm), 4 inches (101 mm) by 4 inches, and 3 inches (76 mm) by 3 inches. When a scrim is used it should be place between two other layers so that its ability to provide integrity to the fabric is maximized.
- Scrims may be made from any polymer known conventionally as being used for that purpose, examples include, polypropylene, ethyl vinyl acetate (EVA), polyamides, polyurethane, polybutylene, polystyrene, polyvinyl chloride, polyethylene, polyethylene terephathalate, and polytetrafluoroethylene.
- EVA ethyl vinyl acetate
- the area in which the web of this invention finds utility is as a dust sock for industrial applications.
- fans are used to move air away from a work area.
- the air moved by the fan contains particulates which must be removed from the air for safety or environmental reasons.
- the fans used to move the air are generally a few feet in diameter and are fitted on the discharge side with a long cylindrical fabric "sock" to catch the particles.
- the Figure shows a dust sock (1) attached to a fan (2) and such a sock may be, for example, about 1 to 2 feet (25 to 61 cm) in diameter and about 8 to 15 feet (244 to 915 cm) in length.
- a dust sock (1) attached to a fan (2) and such a sock may be, for example, about 1 to 2 feet (25 to 61 cm) in diameter and about 8 to 15 feet (244 to 915 cm) in length.
- materials such as cotton and canvas have been used but such materials are quite heavy and do not have the filtration efficiency of the nonwoven fabrics of this invention.
- the more permeable, higher efficiency fabrics of this invention will allow smaller socks to be used than, for example, a canvas sock, for the same particulate load.
- Filter fabrics for use in this invention may have basis weights ranging from about 0.25 osy (8.5 gsm) to about 10 osy (340 gsm).
- the fibers used to produce the web of this invention maybe conjugate fibers, such as side-by-side (S/S) fibers.
- the polymers used to produce the fibers are may be polyamides, polyurethane, polybutylene, polyvinylchloride, polytetrafluoroethylene, polystyrene, polyethylene terephathalate, polycarbonates,
- 4-methyl-1-pentene and polyolefins particulariy polypropylene and polyethylene.
- polyethylenes such as Dow Chemical's ASPUN® 6811
- a linear low density polyethylene, 2553 LLDPE and 25355 and 12350 high density polyethylene are such suitable polymers.
- the polymers mentioned above for scrim production may be used.
- the polyethylenes have melt flow rates in g/10 min. at 190°F and a load of 2.16 kg, of about 26, 40, 25 and 12, respectively.
- Fiber forming polypropylenes include Exxon
- polyamides are nylon-6, nylon 6,6, nylon- 11 and nylon-12. These polyamides are available from a number of sources such as Nyltech North America of Manchester, NH, Emser
- a compatible tackifying resin may be added to the extrudable compositions described above to provide tackified materials that autogenously bond.
- Any tackifier resin can be used which is compatible with the polymers and can withstand the high processing (e.g., extrusion) temperatures. If the polymer is blended with processing aids such as, for example, polyolefins or extending oils, the tackifier resin should also be compatible with those processing aids.
- hydrogenated hydrocarbon resins are preferred tackifying resins, because of their better temperature stability.
- REGALREZ® and ARKON® P series tackifiers are examples of hydrogenated hydrocarbon resins.
- ZONATAC®501 lite is an example of a terpene hydrocarbon.
- REGALREZ® hydrocarbon resins are available from Hercules Inco ⁇ orated.
- ARKON® P series resins are available from Arakawa Chemical (USA) Inco ⁇ orated.
- the tackifying resins such as disclosed in U.S. patent No. 4,787,699, hereby inco ⁇ orated by reference, are suitable.
- Other tackifying resins which are compatible with the other components of the composition and can withstand the high processing temperatures, can also be used. It is also possible to have other materials blended in minor amounts with the polymers used to produce the nonwoven and/or film layer according to this invention like fluorocarbon chemicals to enhance chemical repellency which may be, for example, any of those taught in U.S.
- Fire retardants and pigments for spunbond and meltblown thermoplastic polymers are known in the art and are internal additives.
- a pigment, e.g. TiO 2 if used, is generally present in an amount less than 5 weight percentage of the layer while other materials may be present in a cumulative amount less than 25 weight percent.
- Ultraviolet radiation resistance improving chemical may be, for example, hindered amines and other commerciallly available compounds. Hindered amines are discussed in U.S.
- Patent 5,200,443 to Hudson and examples of such amines are Hostavin TMN 20 from American Hoescht Co ⁇ oration of Somerville, New Jersey, Chimassorb® 944 FL from the Ciba-Geigy Co ⁇ oration of Hawthorne, New York, Cyasorb UV-3668 from American Cyanamid Company of Wayne, New Jersey and Uvasil-299 from Enichem Americas, Inc. of New York. Dust sock laminates of this invention may also have topical treatments applied to them for more specialized functions. Such topical treatments and their methods of application are known in the art and include, for example, alcohol repellency treatments, anti-static treatments and the like, applied by spraying, dipping, etc. An example of such a topical treatment is the application of Zelec® antistat (available from E.I. duPont, Wilmington, Delaware).
- sample data numbered 1-6 include a Comparative Example (1), and examples of webs of the invention (2-5, 7 and 8).
- the testing was done according to the test methods cited above with the differential pressure being measured as described in the NaCl efficiency test manual.
- Sample 1 is a canvas fabric used commercially in the production of dust socks. It has a relatively poor filtration efficiency, high differential pressure and low airflow yet is quite heavy.
- Sample 2 is a laminate of two spunbond fabrics, each of which weighed 2.5 osy (85 gsm) with two meltblown layers having a basis weight of 0.5 osy (17 gsm) each, between them .
- the spunbond was produced from Himont's PF-305 polypropylene and the meltblown from Himont's PF-015.
- the spunbond layers each included about 1.25 weight percent of Chimassorb® 944 FL and the meltblown layers each included about 1 weight percent of the same chemical.
- These layers also had a pigment from the Standridge Chemical Co ⁇ . of Social Circle, GA, present in an amount less than 3 weight percent.
- the particular pigment was SCC- 5181 (tan) though SCC-4876 (blue) and SCC-8992 (gray) are also used.
- Sample 3 is a laminate of two spunbond layers, each of which weighed 1.3 osy (44 gsm). The spunbond layers were produced using Himont's PF-305 polypropylene polymer.
- Sample 4 is a laminate of two spunbond layers, each of which weighed 1.3 osy (44 gsm), between which there is a 2 osy (68 gsm) spunbond layer of side by side polyethylene/polyproplyene.
- the outer spunbond layers were produced using Himont's PF-305.
- the inner spunbond layer was a side-by-side conjugate fabric produced using Himont's PF-305 polypropylene and Dow Chemical's ASPUN® 6811 A in a 50/50 ratio.
- Sample 5 is a laminate of two spunbond fabrics, each of which weighed 2.5 osy (85 gsm). The spunbond was produced from a Himont's PF-305 polymer.
- Sample 6 is an example of a single layer, non-laminated 2.7 osy (92 gsm) fabric.
- the spunbond was a sheath/core conjugate fiber of Dow Chemical's ASPUN® 6811 A polyethylene (sheath) and nylon 6 from Nyltech North America (core).
- Sample 7 is a laminate of two 3 osy (102 gsm) layers of conjugate spunbond fabric using the polymers of the inner spunbond layer of sample 4.
- Sample 8 is a laminate identical to sample 7 except that it included a 5 inch by 5 inch (127 by 127 mm) scrim fabric between the conjugate spunbond layers.
- the scrim was an EVA coated polypropylene available from Conwed Plastics Inc., of Minneapolis, MN.
- the dust sock laminate fabrics of this invention have higher Frazier permeability and higher efficiency than canvas while weighing at least one third less than canvas, i.e., compared to a given canvas fabric, the fabric of this invention will have a higher Frazier permeability and higher NaCl efficiency while weighing about two thirds as much as the canvas. More particularly, it is desired that such dust sock fabrics have an NaCl efficiency above about 60 percent with a basis weight between about 85 and 205 gsm, or still more particularly between about 85 and 170 gsm. It is preferred that the Frazier permeability be above about 100 CFM/SF.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU14182/97A AU1418297A (en) | 1995-12-22 | 1996-12-11 | High efficiency dust sock |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/577,368 | 1995-12-22 | ||
US08/577,368 US5607735A (en) | 1995-12-22 | 1995-12-22 | High efficiency dust sock |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997023265A1 true WO1997023265A1 (en) | 1997-07-03 |
Family
ID=24308408
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1996/019851 WO1997023265A1 (en) | 1995-12-22 | 1996-12-11 | High efficiency dust sock |
Country Status (5)
Country | Link |
---|---|
US (1) | US5607735A (en) |
AU (1) | AU1418297A (en) |
CA (1) | CA2239033A1 (en) |
MX (1) | MX9804960A (en) |
WO (1) | WO1997023265A1 (en) |
Families Citing this family (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IL119809A (en) * | 1996-12-11 | 2001-06-14 | Nicast Ltd | Device for manufacture of composite filtering material and method of its manufacture |
US5785725A (en) * | 1997-04-14 | 1998-07-28 | Johns Manville International, Inc. | Polymeric fiber and glass fiber composite filter media |
DE29821528U1 (en) * | 1998-12-02 | 1999-02-11 | Neu Kalis Spezialpapier Gmbh | Filter bag |
US6372004B1 (en) * | 1999-07-08 | 2002-04-16 | Airflo Europe N.V. | High efficiency depth filter and methods of forming the same |
US6355171B1 (en) * | 1999-11-09 | 2002-03-12 | Oberlin Filter Company | Filter sock for liquid filtration apparatus |
US6815383B1 (en) | 2000-05-24 | 2004-11-09 | Kimberly-Clark Worldwide, Inc. | Filtration medium with enhanced particle holding characteristics |
PT1236494E (en) * | 2001-03-02 | 2004-03-31 | Airflo Europ N V | COMPOSITE FILTER AND METHOD FOR MANUFACTURING |
US20030178122A1 (en) * | 2002-02-14 | 2003-09-25 | Ianniello Peter J. | High friction scrims, geonets, laminates and methods for using and making them |
US20050148266A1 (en) * | 2003-12-30 | 2005-07-07 | Myers David L. | Self-supporting pleated electret filter media |
WO2005083240A1 (en) * | 2004-02-23 | 2005-09-09 | Donaldson Company, Inc. | Crankcase ventilation filter |
US8021457B2 (en) | 2004-11-05 | 2011-09-20 | Donaldson Company, Inc. | Filter media and structure |
US8057567B2 (en) | 2004-11-05 | 2011-11-15 | Donaldson Company, Inc. | Filter medium and breather filter structure |
ES2564057T3 (en) * | 2004-11-05 | 2016-03-17 | Donaldson Company, Inc. | Spray separator |
EP1846136A2 (en) | 2005-02-04 | 2007-10-24 | Donaldson Company, Inc. | Aerosol separator |
EP1858618B1 (en) | 2005-02-22 | 2009-09-16 | Donaldson Company, Inc. | Aerosol separator |
TWI340187B (en) * | 2006-09-21 | 2011-04-11 | Asahi Kasei Fibers Corp | Heat resistant nonwoven fabric |
MX2009009046A (en) * | 2007-02-22 | 2009-10-14 | Donaldson Co Inc | Filter element and method. |
EP2125149A2 (en) | 2007-02-23 | 2009-12-02 | Donaldson Company, Inc. | Formed filter element |
US20090071114A1 (en) * | 2007-03-05 | 2009-03-19 | Alan Smithies | Gas turbine inlet air filtration filter element |
US20080315465A1 (en) * | 2007-03-05 | 2008-12-25 | Alan Smithies | Method of manufacturing composite filter media |
US20080217241A1 (en) * | 2007-03-05 | 2008-09-11 | Alan Smithies | Composite filter media and methods of manufacture |
US8673040B2 (en) | 2008-06-13 | 2014-03-18 | Donaldson Company, Inc. | Filter construction for use with air in-take for gas turbine and methods |
DE102008029480A1 (en) * | 2008-06-20 | 2009-12-24 | Mahle International Gmbh | Multi-layer filter web |
US8267681B2 (en) | 2009-01-28 | 2012-09-18 | Donaldson Company, Inc. | Method and apparatus for forming a fibrous media |
JP6384857B2 (en) * | 2014-07-15 | 2018-09-05 | サコス株式会社 | Dust collection bag with anti-blow part |
MX2017010271A (en) | 2015-02-10 | 2018-03-14 | Walk Ind Inc | Filtration assembly and system. |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4041203A (en) * | 1972-09-06 | 1977-08-09 | Kimberly-Clark Corporation | Nonwoven thermoplastic fabric |
US4605454A (en) * | 1982-09-01 | 1986-08-12 | Kimberly-Clark Corporation | Method of ultrasonically bonding nonwoven webs |
US5108820A (en) * | 1989-04-25 | 1992-04-28 | Mitsui Petrochemical Industries, Ltd. | Soft nonwoven fabric of filaments |
US5306534A (en) * | 1991-03-22 | 1994-04-26 | Home Care Industries, Inc. | Vacuum cleaner bag with electrostatically charged meltblown layer |
US5466516A (en) * | 1990-10-15 | 1995-11-14 | Matarah Industries, Inc. | Thermoplastic fiber laminate |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3338992A (en) * | 1959-12-15 | 1967-08-29 | Du Pont | Process for forming non-woven filamentary structures from fiber-forming synthetic organic polymers |
US3502763A (en) * | 1962-02-03 | 1970-03-24 | Freudenberg Carl Kg | Process of producing non-woven fabric fleece |
US3341394A (en) * | 1966-12-21 | 1967-09-12 | Du Pont | Sheets of randomly distributed continuous filaments |
US3542615A (en) * | 1967-06-16 | 1970-11-24 | Monsanto Co | Process for producing a nylon non-woven fabric |
US3849241A (en) * | 1968-12-23 | 1974-11-19 | Exxon Research Engineering Co | Non-woven mats by melt blowing |
DE2048006B2 (en) * | 1969-10-01 | 1980-10-30 | Asahi Kasei Kogyo K.K., Osaka (Japan) | Method and device for producing a wide nonwoven web |
DE1950669C3 (en) * | 1969-10-08 | 1982-05-13 | Metallgesellschaft Ag, 6000 Frankfurt | Process for the manufacture of nonwovens |
US4340563A (en) * | 1980-05-05 | 1982-07-20 | Kimberly-Clark Corporation | Method for forming nonwoven webs |
US4374888A (en) * | 1981-09-25 | 1983-02-22 | Kimberly-Clark Corporation | Nonwoven laminate for recreation fabric |
US4787699A (en) * | 1987-09-01 | 1988-11-29 | Hughes Aircraft Company | Fiber optic terminus |
US5169706A (en) * | 1990-01-10 | 1992-12-08 | Kimberly-Clark Corporation | Low stress relaxation composite elastic material |
US5149576A (en) * | 1990-11-26 | 1992-09-22 | Kimberly-Clark Corporation | Multilayer nonwoven laminiferous structure |
US5200443A (en) * | 1991-03-29 | 1993-04-06 | Kimberly-Clark Corporation | Radiation stabilized fabric having improved odor characteristics containing an hindered amine compound |
US5382400A (en) * | 1992-08-21 | 1995-01-17 | Kimberly-Clark Corporation | Nonwoven multicomponent polymeric fabric and method for making same |
US5336552A (en) * | 1992-08-26 | 1994-08-09 | Kimberly-Clark Corporation | Nonwoven fabric made with multicomponent polymeric strands including a blend of polyolefin and ethylene alkyl acrylate copolymer |
-
1995
- 1995-12-22 US US08/577,368 patent/US5607735A/en not_active Expired - Fee Related
-
1996
- 1996-12-11 AU AU14182/97A patent/AU1418297A/en not_active Abandoned
- 1996-12-11 CA CA002239033A patent/CA2239033A1/en not_active Abandoned
- 1996-12-11 WO PCT/US1996/019851 patent/WO1997023265A1/en active Application Filing
-
1998
- 1998-06-19 MX MX9804960A patent/MX9804960A/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4041203A (en) * | 1972-09-06 | 1977-08-09 | Kimberly-Clark Corporation | Nonwoven thermoplastic fabric |
US4605454A (en) * | 1982-09-01 | 1986-08-12 | Kimberly-Clark Corporation | Method of ultrasonically bonding nonwoven webs |
US5108820A (en) * | 1989-04-25 | 1992-04-28 | Mitsui Petrochemical Industries, Ltd. | Soft nonwoven fabric of filaments |
US5466516A (en) * | 1990-10-15 | 1995-11-14 | Matarah Industries, Inc. | Thermoplastic fiber laminate |
US5306534A (en) * | 1991-03-22 | 1994-04-26 | Home Care Industries, Inc. | Vacuum cleaner bag with electrostatically charged meltblown layer |
Also Published As
Publication number | Publication date |
---|---|
AU1418297A (en) | 1997-07-17 |
CA2239033A1 (en) | 1997-07-03 |
MX9804960A (en) | 1998-09-30 |
US5607735A (en) | 1997-03-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5607735A (en) | High efficiency dust sock | |
KR100405874B1 (en) | Protective Cover Fabric Including Nonwovens | |
EP0690163B1 (en) | Nonwoven laminated fabrics | |
CN101674873B (en) | Bag house filters and media | |
EP1276548B1 (en) | Filter media | |
US4908163A (en) | Nonwoven medical fabric | |
US5709735A (en) | High stiffness nonwoven filter medium | |
MXPA05000776A (en) | Acoustical insulation material containing fine thermoplastic fibers. | |
CA1290517C (en) | Nonwoven fabric with improved abrasion resistance | |
EP0606244A1 (en) | Novel material and material properties from multilayer blown microfiber webs. | |
JPH07300754A (en) | Polyethylene melt blown fabric with barrier property | |
CA2238441A1 (en) | Oil absorbent material with superior abrasive resistant properties | |
US5762734A (en) | Process of making fibers | |
AU641744B2 (en) | Filter | |
CA2482407A1 (en) | Coform filter media having increased particle loading capacity | |
EP0043390B1 (en) | Composite sheet structure, process for its preparation and laminates comprising said structure | |
EP1517788A4 (en) | Improved abrasion resistance of nonwovens | |
CA2231507C (en) | High stiffness nonwoven filter medium | |
MXPA99001610A (en) | Single extruder multiportion fiber | |
CA2249317A1 (en) | Spunbond vacuum cleaner webs | |
MXPA98001145A (en) | Protective cover fabric including non-teji |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AL AM AT AU AZ BB BG BR BY CA CH CN CZ DE DK EE ES FI GB GE HU IL IS JP KE KG KP KR KZ LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TR TT UA UG UZ VN AM AZ BY KG KZ MD RU TJ TM |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): KE LS MW SD SZ UG AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
ENP | Entry into the national phase |
Ref document number: 2239033 Country of ref document: CA Ref document number: 2239033 Country of ref document: CA Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: PA/A/1998/004960 Country of ref document: MX |
|
NENP | Non-entry into the national phase |
Ref document number: 97508729 Country of ref document: JP |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
122 | Ep: pct application non-entry in european phase |