WO2002040234A2 - Crosslinked cellulosic product - Google Patents
Crosslinked cellulosic product Download PDFInfo
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- WO2002040234A2 WO2002040234A2 PCT/US2001/046004 US0146004W WO0240234A2 WO 2002040234 A2 WO2002040234 A2 WO 2002040234A2 US 0146004 W US0146004 W US 0146004W WO 0240234 A2 WO0240234 A2 WO 0240234A2
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- Prior art keywords
- product
- fibers
- cellulosic
- bonded
- fibrous
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F13/00—Bandages or dressings; Absorbent pads
- A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
- A61F13/53—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium
- A61F13/531—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having a homogeneous composition through the thickness of the pad
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F13/00—Bandages or dressings; Absorbent pads
- A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
- A61F13/15577—Apparatus or processes for manufacturing
- A61F13/15617—Making absorbent pads from fibres or pulverulent material with or without treatment of the fibres
- A61F13/15626—Making fibrous pads without outer layers
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- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
- D04H1/587—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives characterised by the bonding agents used
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/58—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives
- D04H1/64—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by applying, incorporating or activating chemical or thermoplastic bonding agents, e.g. adhesives the bonding agent being applied in wet state, e.g. chemical agents in dispersions or solutions
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F13/00—Bandages or dressings; Absorbent pads
- A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
- A61F13/53—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium
- A61F2013/530481—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having superabsorbent materials, i.e. highly absorbent polymer gel materials
- A61F2013/530489—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having superabsorbent materials, i.e. highly absorbent polymer gel materials being randomly mixed in with other material
Definitions
- the present invention relates generally to a cellulosic fibrous product and, more particularly, to a bonded cellulosic fibrous product that includes crosslinked cellulosic fibers.
- Crosslinked cellulosic fibers are advantageously incorporated into a variety of fibrous products to enhance product bulk, resilience, and dryness.
- Absorbent articles such as diapers, are typically formed from fibrous composites that include absorbent fibers such as wood pulp fibers, and can additionally include crosslinked cellulosic fibers.
- absorbent fibers such as wood pulp fibers
- crosslinked cellulosic fibers When incorporated into absorbent articles, such fibrous composites can provide a product that offers the advantages of high liquid acquisition rate and high liquid wicking capacity imparted by the crosslinked fibers and absorbent fibers, respectively.
- fibrous composites that include relatively high percentages of crosslinked fibers suffer from low sheet strength.
- Personal care absorbent products for example, infant diapers, adult incontinence products, and feminine care products, include liquid acquisition and/or distribution layers that serve to rapidly acquire and then distribute acquired liquid to a storage core for retention.
- these layers may include crosslinked cellulosic fibers, which impart bulk and resilience to the layers.
- webs that include high proportions of crosslinked fibers suffer from a lack of structural integrity.
- the problem of loss of structural integrity is traditionally addressed by sandwiching webs that include crosslinked fibers between either tissues and nonwoven sheets and secured with an adhesive. Such structures are required to seek to maintain web integrity.
- the present invention provides a bonded cellulosic fibrous product that includes crosslinked cellulosic fibers.
- the product includes a bonding agent.
- the product can optionally include other fibers alone, absorbent materials alone, or other fibers and absorbent materials.
- methods for forming the bonded cellulosic fibrous product is provided.
- the present invention provides absorbent articles that include the bonded cellulosic fibrous product.
- the product can be combined with one or more other layers to provide structures that can be incorporated into absorbent articles such as infant diapers, adult incontinence products, and feminine care products.
- FIGURE 1 is a diagrammatic illustration of a representative drum former device and method for forming the product of the invention.
- FIGURE 2 is a diagrammatic illustration of a representative pocket former device and method for forming the product of the invention.
- the present invention provides a bonded cellulosic fibrous product that includes bonded crosslinked cellulosic fibers.
- the product possesses the advantageous properties of bulk and resiliency associated with in rafiber crosslinked fibers and the advantage of structural integrity imparted to the structure by the bonding between fibers.
- the product is a bonded web in which the crosslinked fibers and the bonded structure of the web itself contribute to the resiliency and liquid acquisition performance of the web.
- 'bonding between fibers can be attained by treating the fibers with a crosslinking agent and/or a bonding agent.
- the product is formed by treating the crosslinked cellulosic fibers with a crosslinking agent and, if necessary, a crosslinking catalyst. In another embodiment, the product is formed by treating the crosslinked cellulosic fibers with a bonding agent. In a further embodiment, the product is formed by treating the crosslinked cellulosic fibers with a combination of crosslinking agent and, if necessary, catalyst, and bonding agent.
- the product can be formed by (1) forming a web of crosslinked cellulosic fibers; (2) treating the web with either (a) a crosslinking agent and, if necessary, a crosslinking catalyst, (b) a bonding agent, or (c) a crosslinking agent and, if necessary, a crosslinking catalyst, and a bonding agent; and (3) heating the web at a temperature and for a time sufficient to effect interfiber crosslinking and bonding between fibers.
- the bonded cellulosic fibrous product includes in situ crosslinked cellulosic fibers.
- in situ crosslinked cellulosic fibers refers to cellulosic fibers that have been crosslinked during the formation of the web. Therefore, the product is distinguishable from webs that include crosslinked cellulosic fibers that are first formed and then introduced to the web during the web formation process.
- the product includes in situ crosslinked cellulosic fibers, because the fibers are crosslinked during the web formation process (i.e., in situ), the product includes intrafiber crosslinked cellulosic fibers (i.e., fibers having crosslinks within each fiber) that have been interfiber crosslinked (i.e., fibers having crosslinks between fibers).
- the product has a bonded structure and includes intrafiber crosslinked cellulosic fibers that are further crosslinked to adjacent fibers through interfiber crosslinks.
- the product possesses the advantageous properties of bulk and resiliency associated with intrafiber crosslinked fibers and the advantage of structural integrity imparted to the structure by the bonding between fibers.
- the product is a bonded web in which the crosslinked fibers and the bonded structure of the web itself contribute to the resiliency and liquid acquisition performance of the web.
- the product can be produced by (1) forming a web of cellulosic fibers, at least some of which having been treated with a crosslinking agent and, if necessary, crosslinking catalyst; and (2) heating the web at a temperature and for a time sufficient to effect crosslinking.
- the product can be formed by (1) forming a web of cellulosic fibers; (2) treating the web with a crosslinking agent and, if necessary, a crosslinking catalyst; and (3) heating the web at a temperature and for a time sufficient to effect crosslinking.
- Suitable fibers useful in forming the product of the invention include cellulosic fibers that have been treated with a crosslinking agent and, if necessary, crosslinking catalyst and then dried without curing the crosslinking agent. These dried and treated fibers can be introduced into the forming device for subsequent product formation.
- crosslinking agents and crosslinking catalysts can be used to provide the product of the invention.
- the following is a representative list of useful crosslinking agents and catalysts.
- Each of the patents noted below is expressly incorporated herein by reference in its entirety.
- Suitable urea-based crosslinking agents include substituted ureas such as methylolated ureas, methylolated cyclic ureas, methylolated lower alkyl cyclic ureas, methylolated dihydroxy cyclic ureas, dihydroxy cyclic ureas, and lower alkyl substituted cyclic ureas.
- Specific urea-based crosslinking agents include dimethyldihydroxy urea (DMDHU, l,3-dimethyl-4,5-dihydroxy-2-imidazolidinone), dimethyloldihydroxy-ethylene urea (DMDHEU, l,3-dihydroxymethyl-4,5-dihydroxy- 2-imidazolidinone), dimethylol urea (DMU, bis[N-hydroxymethyl]urea), dihydroxyethylene urea (DHEU, 4,5-dihydroxy-2-imidazolidinone), dimethylolethylene urea (DMEU, l,3-dihydroxymethyl-2-imidazolidinone), and dimethyldihydroxyethylene urea (DDI, 4,5-dihydroxy-l,3-dimethyl-2- imidazolidinone) .
- DMDHU dimethyldihydroxy urea
- DMDHEU dimethyloldihydroxy-ethylene urea
- DMDHEU dimethyloldihydroxy-ethylene urea
- Suitable crosslinking agents include dialdehydes such as C -C 8 dialdehydes (e.g., glyoxal), C 2 -C 8 dialdehyde acid analogs having at least one aldehyde group, and oligomers of these aldehyde and dialdehyde acid analogs, as described in U.S. Patents Nos. 4,822,453; 4,888,093; 4,889,595; 4,889,596; 4,889,597; and 4,898,642.
- Other suitable dialdehyde crosslinking agents include those described in U.S. Patents Nos. 4,853,086; 4,900,324; and 5,843,061.
- crosslinking agents include aldehyde and urea-based formaldehyde addition products. See, for example, U.S. Patents Nos. 3,224,926; 3,241,533; 3,932,209; 4,035,147; 3 756,913; 4,689,118; 4,822,453; 3,440,135; 4,935,022; 3,819,470; and 3,658,613.
- Suitable crosslinking agents include glyoxal adducts of ureas, for example, U.S. Patent No. 4,968,774, and glyoxal/cyclic urea adducts as described in U.S. Patents Nos. 4,285,690; 4,332,586; 4,396,391; 4,455,416; and 4,505,712.
- crosslinking agents include carboxylic acid crosslinking agents such as polycarboxylic acids.
- Polycarboxylic acid crosslinking agents e.g., citric acid, propane tricarboxylic acid, and butane tetracarboxylic acid
- catalysts are described in U.S. Patents Nos. 3,526,048; 4,820,307; 4,936,865; 4,975,209; and 5,221,285.
- C 2 -C polycarboxylic acids that contain at least three carboxyl groups e.g., citric acid and oxydisuccinic acid
- C 2 -C polycarboxylic acids that contain at least three carboxyl groups (e.g., citric acid and oxydisuccinic acid) as crosslinking agents is described in U.S. Patents Nos. 5,137,537; 5,183,707; 5,190,563; 5,562,740, and 5,873,979.
- Polymeric polycarboxylic acids are also suitable crosslinking agents.
- Suitable polymeric polycarboxylic acid crosslinking agents are described in U.S. Patents Nos. 4,391,878; 4,420,368; 4,431,481; 5,049,235; 5,160,789; 5,442,899; 5,698,074; 5,496,476; 5,496,477; 5,728,771; 5,705,475; and 5,981,739.
- Polyacrylic acid and related copolymers as crosslinking agents are described U.S. Patents Nos. 6,306,251; 5,549,791; and 5,998,511.
- Polymaleic acid crosslinking agents are described in U.S. Patent No. 5,998,511.
- polycarboxylic acid crosslinking agents include citric acid, tartaric acid, malic acid, succinic acid, glutaric acid, citraconic acid, itaconic acid, tartrate monosuccinic acid, maleic acid, polyacrylic acid, polymethacrylic acid, polymaleic acid, polymethylvinylether-co-maleate copolymer, polymethylvinylether- co-itaconate copolymer, copolymers of acrylic acid, and copolymers of maleic acid.
- Other suitable crosslinking agents are described in U.S. Patents Nos. 5,225,047;
- Suitable catalysts can include acidic salts, such as ammonium chloride, ammonium sulfate, aluminum chloride, magnesium chloride, magnesium nitrate, and alkali metal salts of phosphorous-containing acids.
- the crosslinking catalyst is sodium hypophosphite.
- crosslinking agent is applied to the cellulosic fibers in an amount sufficient to effect intrafiber crosslinking and interfiber crosslinking as described above.
- the amount applied to the cellulosic fibers can be from about 1 to about 10 percent by weight based on the total weight of fibers, i one embodiment, crosslinking agent in an amount from about 4 to about 6 percent by weight based on the total weight of fibers.
- Suitable cellulosic fibers for forming the product of the invention include those known to those skilled in the art and include any fiber or fibrous mixture that can be crosslinked and from which a fibrous web or sheet can be formed.
- cellulosic fibers are derived primarily from wood pulp.
- Suitable wood pulp fibers for use with the invention can be obtained from well-known chemical processes such as the kraft and sulfite processes, with or without subsequent bleaching. Pulp fibers can also be processed by thermomechanical, chemithermomechanical methods, or combinations thereof. The preferred pulp fiber is produced by chemical methods. Groundwood fibers, recycled or secondary wood pulp fibers, and bleached and unbleached wood pulp fibers can be used. Softwoods and hardwoods can be used. Details of the selection of wood pulp fibers are well known to those skilled in the art. These fibers are commercially available from a number of companies, including Weyerhaeuser Company, the assignee of the present invention. For example, suitable cellulose fibers produced from southern pine that are usable with the present invention are available from Weyerhaeuser Company under the designations CF416, NF405, PL416, FR516, and B416.
- the wood pulp fibers useful in the present invention can also be pretreated prior to use.
- This pretreatment may include physical treatment, such as subjecting the fibers to steam, or chemical treatment.
- pretreating fibers include the application of surfactants or other liquids, which modify the surface chemistry of the fibers.
- Other pretreatments include incorporation of antimicrobials, pigments, dyes and densification or softening agents.
- Fibers pretreated with other chemicals, such as thermoplastic and thermosetting resins also may be used. Combinations of pretreatments also may be employed. Similar treatments can also be applied after formation of the fibrous product in post-treatment processes.
- Cellulosic fibers treated with particle binders and/or densification/softness aids known in the art can also be employed in accordance with the present invention.
- the particle binders serve to attach other materials, such as superabsorbent polymers, as well as others, to the cellulosic fibers.
- Cellulosic fibers treated with suitable particle binders and/or densification/softness aids and the process for combining them with cellulose fibers are disclosed in the following U.S. patents: (1) Patent No. 5,543,215, entitled “Polymeric Binders for Binding Particles to Fibers"; (2) Patent No. 5,538,783, entitled “Non-Polymeric Organic Binders for Binding Particles to Fibers"; (3) Patent No.
- Patent No. 5,300,192 entitled “Wet Laid Fiber Sheet Manufacturing With Reactivatable Binders for Binding Particles to Binders”
- Patent No. 5,352,480 entitled “Method for Binding Particles to Fibers Using Reactivatable Binders”
- Patent No. 5,308,896 entitled “Particle Binders for High-Bulk Fibers”
- Patent No. 5,589,256 entitled “Particle Binders that Enhance Fiber Densification”
- Patent No. 5,609,727 entitled “Fibrous Product for Binding Particles”
- Patent No. 5,571,618, entitled “Reactivatable Binders for Binding Particles to Fibers” Patent No. 5,447,977, entitled “Particle Binders for High Bulk Fibers”
- Patent No. 5,614, 570 entitled “Absorbent Articles Containing Binder Carrying High Bulk Fibers
- Patent No. 5,611,885, entitled “Particle Binders” each expressly incorporated herein by reference.
- synthetic fibers including polymeric fibers, such as polyolefin, polyamide, polyester, polyvinyl alcohol, polyvinyl acetate fibers, can also be incorporated into the product.
- Suitable synthetic fibers include, for example, polyethylene terephthalate, polyethylene, polypropylene, nylon, and rayon fibers.
- Other suitable synthetic fibers include those made from thermoplastic polymers, cellulosic and other fibers coated with thermoplastic polymers, and multicomponent fibers in which at least one of the components includes a thermoplastic polymer.
- Single and multicomponent fibers can" be manufactured from polyester, polyethylene, polypropylene, and other conventional thermoplastic fibrous materials. Single and multicomponent fibers are commercially available.
- Suitable bicomponent fibers include CELBOND fibers available from Hoechst-Celanese Company.
- the product can also include combinations of natural and synthetic fibers.
- the product further includes a bonding agent.
- the bonding agent serves to further enhance the structural integrity of the product.
- Suitable bonding agents include thermoplastic materials, such as bicomponent fibers and latexes, and wet strength agents.
- the bonding agent is a thermoplastic fiber
- the fiber can be combined with cellulosic fibers and then formed into the web to be subsequently heated.
- the bonding agent is a wet strength agent
- the bonding agent can be applied to the web prior to subjecting the web to fiber crosslinking conditions (i.e., curing).
- Suitable thermoplastic fibers include cellulosic and other fibers coated with thermoplastic polymers, and multicomponent fibers in which at least one of the components includes a thermoplastic polymer.
- Single and multicomponent fibers can be manufactured from polyester, polyethylene, polypropylene, and other conventional thermoplastic fibrous materials. Single and multicomponent fibers are commercially available.
- Suitable bicomponent fibers include CELBOND fibers available from Hoechst-Celanese Company.
- Suitable wet strength agents include cationic modified starch having nitrogen- containing groups (e.g., amino groups) such as those available from National Starch and Chemical Corp., Bridgewater, NJ; latex; wet strength resins, such as polyamide- epichlorohydrin resin (e.g., KYMENE 557LX, Hercules, Inc., Wilmington, DE), and polyacrylamide resin (see, e.g., U.S. Patent No. 3,556,932 and also the commercially available polyacrylamide marketed by American Cyanamid Co., Stanford, CT, under the trade name PAREZ 631 NC); urea formaldehyde and melamine formaldehyde resins; and polyethylenimine resins.
- nitrogen- containing groups e.g., amino groups
- wet strength resins such as polyamide- epichlorohydrin resin (e.g., KYMENE 557LX, Hercules, Inc., Wilmington, DE), and polyacrylamide resin (see, e.g
- the product can include other fibers.
- Other fibers include, for example, the cellulosic fibers, particularly the wood pulp fibers described above, as well as hemp, bagasse, cotton, groundwood, bleached and unbleached pulp, recycled or secondary fibers.
- the product can further include absorbent material (e.g., superabsorbent polymer particles).
- the term "absorbent material” refers to a material that absorbs liquid and that generally has an absorbent capacity greater than the cellulosic fibrous component of the composite.
- the absorbent material is a water-swellable, generally water-insoluble polymeric material capable of absorbing at least about 5, desirably about 20, and preferably about 100 times or more its weight in saline (e.g., 0.9 percent saline).
- the amount of absorbent material present in the product can vary greatly depending on the product's intended use.
- Absorbent material can be present in the product in an amount greater than about 0.5 percent by weight based on the total weight of the product.
- the absorbent material may include natural materials such as agar, pectin, and guar gum, and synthetic materials, such as synthetic hydrogel polymers.
- Synthetic hydrogel polymers include, for example, carboxymethyl cellulose, alkaline metal salts of polyacrylic acid, polyacrylamides, polyvinyl alcohol, ethylene maleic anhydride copolymers, polyvinyl ethers, hydroxypropyl cellulose, polyvinyl morpholinone, polymers and copolymers of vinyl sulphonic acid, polyacrylates, polyacrylamides, and polyvinyl pyridine among others, i one embodiment, the absorbent material is a superabsorbent material.
- a "superabsorbent material” refers to a polymeric material that is capable of absorbing large quantities of fluid by swelling and forming a hydrated gel (i.e., a hydrogel). In addition to absorbing large quantities of fluids, superabsorbent materials can also retain significant amounts of bodily fluids under moderate pressure.
- Superabsorbent materials generally fall into three classes: starch graft copolymers, crosslinked carboxymethylcellulose derivatives, and modified hydrophilic polyacrylates.
- absorbent polymers include hydrolyzed starch- acrylonitrile graft copolymers, neutralized starch-acrylic acid graft copolymers, saponified acrylic acid ester- inyl acetate copolymers, hydrolyzed acrylonitrile copolymers or acrylamide copolymers, modified crosslinked polyvinyl alcohol, neutralized self-crosslinking polyacrylic acids, crosslinked polyacrylate salts, carboxylated cellulose, and neutralized crosslinked isobutylene-maleic anhydride copolymers.
- Superabsorbent materials are available commercially, for example, polyacrylates from Clariant of Portsmouth, Virginia. These superabsorbent polymers come in a variety of sizes, morphologies, and absorbent properties (available from Clariant under trade designations such as IM 3500 and IM 3900). Other superabsorbent materials are marketed under the trademarks SANWET (supplied by Sanyo Kasei Kogyo Kabushiki Kaisha), and SXM77 (supplied by Stockhausen of Greensboro, North Carolina). Other superabsorbent materials are described in U.S. Patent No. 4,160,059; U.S. Patent No. 4,676,784; U.S. Patent No. 4,673,402; U.S. Patent No.
- Suitable superabsorbent materials useful in the product include superabsorbent particles and superabsorbent fibers.
- methods for forming the bonded cellulosic fibrous product are provided.
- the product is formed using a drum former.
- the product is formed using a pocket former.
- the product of the invention is formed by subjecting a web that includes cellulosic fibers treated with crosslinking agent and, if necessary, crosslinking catalyst, and bonding agent, if included, to a temperature and for a time sufficient to effect crosslinking (i.e., curing) and fiber bonding.
- the curing of the crosslinking agent to provide the product can be performed by several methods.
- Crosslinking typically requires a relatively high temperature (180°C) and long reaction times (greater than 4 minutes), h one embodiment, the product is formed by heating in a curing oven in which high temperature and large volumes of air are drawn through the web.
- curing takes place after the webs have been placed in boxes for shipping. In this embodiment, boxes containing the treated webs are passed through a dryer (e.g., a kiln dryer) to complete the crosslinking reaction.
- a dryer e.g., a kiln dryer
- the product is produced using pocket forming (mold) technology.
- fibers e.g., crosslinked cellulosic fibers treated with crosslinking agent and, if necessary, catalyst, and optional thermoplastic fibers; or cellulosic fibers treated with crosslinking agent and, if necessary, catalyst, and optional thermoplastic fibers
- a forming device that includes a pocket or mold that forms the fibers into a desired shape (e.g., the shape of an acquisition zone to be used in an absorbent product such as an infant diaper, adult incontinence product, or feminine care product).
- the bonding agent can be applied to the fibers prior to curing.
- the crosslinking agent can be applied to the fibers at a point prior to their curing.
- the product is produced by heating the pockets in which the treated cellulosic fiber web is formed. By such a method, bonded webs having the desired shapes are directly formed. By this method, a continuous web of the desired shape can be formed and packaged into a box ready for shipping and subsequent use by the absorbent product producer.
- the product is formed by airlaying crosslinked cellulosic fibers and bicomponent fibers.
- the product is formed by airlaying crosslinked cellulosic fibers and a wet strength agent.
- the product is formed by airlaying crosslinked cellulosic fibers and a crosslinking agent and, if necessary, catalyst.
- the product is formed by airlaying cellulosic fibers treated with a crosslinking agent and, if necessary, crosslinking catalyst, and bicomponent fibers, and then heating the airlaid fibers to cure the crosslinking agent and effect fiber bonding.
- the product of the present invention can be formed as an extended web or sheet that has structural integrity and sheet strength sufficient to permit the fibrous web to be rolled, transported, and used in rolled form in subsequent processes.
- the product of the present invention can be supplied in a fibrous rolled form and readily incorporated into subsequent processes.
- the product can be advantageously incorporated into a variety of absorbent articles, such as diapers, including disposable diapers and training pants; feminine care products, including sanitary napkins, tampons, and pant liners; adult incontinence products; toweling; surgical and dental sponges; bandages; food tray pads; and the like.
- absorbent articles such as diapers, including disposable diapers and training pants; feminine care products, including sanitary napkins, tampons, and pant liners; adult incontinence products; toweling; surgical and dental sponges; bandages; food tray pads; and the like.
- a representative bonded web formed in accordance with the present invention (a bonded web including in situ crosslinked fibers) is described below.
- the acquisition rate (ml/sec) for four liquid insults, rewet (g), median uptake pressure (MUP) capacity (g/g), and median desorption pressure (MDP, cm) for representative bonded webs compared to controls are presented in Table 1.
- Control A refers to a commercial infant diaper (Procter & Gamble) having a crosslinked cellulosic fiber acquisition layer
- Control B refers to a commercial infant diaper (PAMPERS) having a dual acquisition layer composed of a 44 gam synthetic layer and 300 gsm crosslinked fiber (citric acid crosslinked fibers) layer.
- Webs 1A, 2A, IB, and 2B refer to representative products of the invention.
- Webs 1A and IB refer to products formed from 100 percent by weight flash-dried cellulosic fibers treated with citric acid as crosslinking agent (about 6 percent by weight based on the total weight of fibers) and a catalyst.
- Webs 2A and 2B refer to products formed from 90 percent by weight flash-dried cellulosic fibers treated with citric acid as crosslinking agent (about 6 percent by weight based on the total weight of fibers) and a catalyst and 10 percent by weight bicomponent binder fibers (CELBOND T105).
- the target basis weight for Webs 1A and 2A was 150 g/m 2
- the target basis weight for Webs IB and 2B was 300 g/m 2 .
- TABLE 1. PERFORMANCE CHARACTERISTICS OF REPRESENTATIVE PRODUCTS.
- the present invention provides absorbent articles that include the bonded cellulosic fibrous product.
- the product can be combined with one or more other layers to provide structures that can be incorporated into absorbent articles such as infant diapers, adult incontinence products, and feminine care products.
Abstract
Description
Claims
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002542584A JP2004526871A (en) | 2000-11-14 | 2001-11-14 | Crosslinked cellulose products |
BR0115341-2A BR0115341A (en) | 2000-11-14 | 2001-11-14 | Method for making a cellulosic fibrous product, bound cellulosic fibrous product, and personal care absorbent product |
CA002427654A CA2427654A1 (en) | 2000-11-14 | 2001-11-14 | Crosslinked cellulosic product |
MXPA03004202A MXPA03004202A (en) | 2000-11-14 | 2001-11-14 | Crosslinked cellulosic product. |
AU2002233966A AU2002233966A1 (en) | 2000-11-14 | 2001-11-14 | Crosslinked cellulosic product |
EP01984969A EP1358051A2 (en) | 2000-11-14 | 2001-11-14 | Crosslinked cellulosic product |
NO20032154A NO20032154L (en) | 2000-11-14 | 2003-05-13 | Crosslinked cellulosic product |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US24835000P | 2000-11-14 | 2000-11-14 | |
US24826000P | 2000-11-14 | 2000-11-14 | |
US60/248,260 | 2000-11-14 | ||
US60/248,350 | 2000-11-14 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2002040234A2 true WO2002040234A2 (en) | 2002-05-23 |
WO2002040234A3 WO2002040234A3 (en) | 2002-09-06 |
Family
ID=26939234
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2001/046004 WO2002040234A2 (en) | 2000-11-14 | 2001-11-14 | Crosslinked cellulosic product |
Country Status (10)
Country | Link |
---|---|
US (1) | US20020112296A1 (en) |
EP (1) | EP1358051A2 (en) |
JP (1) | JP2004526871A (en) |
CN (1) | CN1474676A (en) |
AU (1) | AU2002233966A1 (en) |
BR (1) | BR0115341A (en) |
CA (1) | CA2427654A1 (en) |
MX (1) | MXPA03004202A (en) |
NO (1) | NO20032154L (en) |
WO (1) | WO2002040234A2 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3558638B2 (en) * | 1994-03-25 | 2004-08-25 | ウェヤーハウザー・カンパニー | Multiply cellulose products using bulky cellulose fibers |
US7195695B2 (en) * | 2003-10-02 | 2007-03-27 | Rayonier Products & Financial Services Company | Cross-linked cellulose fibers and method of making same |
US7513973B2 (en) * | 2004-03-31 | 2009-04-07 | Weyerhaeuser Nr Company | Bleached polyacrylic acid crosslinked cellulosic fibers |
US20080000603A1 (en) * | 2006-06-29 | 2008-01-03 | Neogi Amar N | Covalent Bonding of Carboxylated Cellulose Fiber Webs |
KR100786974B1 (en) | 2007-03-16 | 2007-12-17 | 이승인 | Pollution-free urea resin and method for producing tenacity viscose rayon filament yarn using the same |
US9133583B2 (en) | 2011-04-05 | 2015-09-15 | P.H. Glatfelter Company | Process for making a stiffened paper |
US8496784B2 (en) * | 2011-04-05 | 2013-07-30 | P.H. Glatfelter Company | Process for making a stiffened paper |
SE542866C2 (en) * | 2018-04-04 | 2020-07-21 | Stora Enso Oyj | Method for manufacturing a dry-laid mat for thermoforming |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4204054A (en) * | 1975-10-20 | 1980-05-20 | S. A. Beghin-Say | Paper structures containing improved cross-linked cellulose fibers |
US4252761A (en) * | 1978-07-14 | 1981-02-24 | The Buckeye Cellulose Corporation | Process for making spontaneously dispersible modified cellulosic fiber sheets |
US5399240A (en) * | 1987-01-20 | 1995-03-21 | Weyerhaeuser Company | Crosslinked cellulose products and method for their preparation |
US5486167A (en) * | 1991-01-03 | 1996-01-23 | The Procter & Gamble Company | Absorbent article having blended multi-layer absorbent structure with improved integrity |
WO1998024960A1 (en) * | 1996-12-06 | 1998-06-11 | Weyerhaeuser Company | Air-laid unitary absorbent layer |
-
2001
- 2001-11-14 JP JP2002542584A patent/JP2004526871A/en active Pending
- 2001-11-14 MX MXPA03004202A patent/MXPA03004202A/en not_active Application Discontinuation
- 2001-11-14 US US10/002,373 patent/US20020112296A1/en not_active Abandoned
- 2001-11-14 CN CNA018188486A patent/CN1474676A/en active Pending
- 2001-11-14 EP EP01984969A patent/EP1358051A2/en not_active Withdrawn
- 2001-11-14 CA CA002427654A patent/CA2427654A1/en not_active Abandoned
- 2001-11-14 WO PCT/US2001/046004 patent/WO2002040234A2/en not_active Application Discontinuation
- 2001-11-14 BR BR0115341-2A patent/BR0115341A/en not_active IP Right Cessation
- 2001-11-14 AU AU2002233966A patent/AU2002233966A1/en not_active Abandoned
-
2003
- 2003-05-13 NO NO20032154A patent/NO20032154L/en not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4204054A (en) * | 1975-10-20 | 1980-05-20 | S. A. Beghin-Say | Paper structures containing improved cross-linked cellulose fibers |
US4252761A (en) * | 1978-07-14 | 1981-02-24 | The Buckeye Cellulose Corporation | Process for making spontaneously dispersible modified cellulosic fiber sheets |
US5399240A (en) * | 1987-01-20 | 1995-03-21 | Weyerhaeuser Company | Crosslinked cellulose products and method for their preparation |
US5486167A (en) * | 1991-01-03 | 1996-01-23 | The Procter & Gamble Company | Absorbent article having blended multi-layer absorbent structure with improved integrity |
WO1998024960A1 (en) * | 1996-12-06 | 1998-06-11 | Weyerhaeuser Company | Air-laid unitary absorbent layer |
Also Published As
Publication number | Publication date |
---|---|
WO2002040234A3 (en) | 2002-09-06 |
MXPA03004202A (en) | 2003-09-22 |
EP1358051A2 (en) | 2003-11-05 |
AU2002233966A1 (en) | 2002-05-27 |
JP2004526871A (en) | 2004-09-02 |
NO20032154D0 (en) | 2003-05-13 |
CA2427654A1 (en) | 2002-05-23 |
NO20032154L (en) | 2003-05-13 |
CN1474676A (en) | 2004-02-11 |
US20020112296A1 (en) | 2002-08-22 |
BR0115341A (en) | 2004-02-03 |
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