US20040224588A1 - Absorbent structures of chemically treated cellulose fibers - Google Patents
Absorbent structures of chemically treated cellulose fibers Download PDFInfo
- Publication number
- US20040224588A1 US20040224588A1 US10/866,210 US86621004A US2004224588A1 US 20040224588 A1 US20040224588 A1 US 20040224588A1 US 86621004 A US86621004 A US 86621004A US 2004224588 A1 US2004224588 A1 US 2004224588A1
- Authority
- US
- United States
- Prior art keywords
- fibers
- fiber
- group
- polyvalent cation
- article
- 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
Images
Classifications
-
- 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
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
- A61L15/28—Polysaccharides or their derivatives
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/42—Use of materials characterised by their function or physical properties
- A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
-
- 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
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
- D06M11/07—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with halogens; with halogen acids or salts thereof; with oxides or oxyacids of halogens or salts thereof
- D06M11/11—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with halogens; with halogen acids or salts thereof; with oxides or oxyacids of halogens or salts thereof with halogen acids or salts thereof
- D06M11/17—Halides of elements of Groups 3 or 13 of the Periodic System
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
- D06M11/32—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond
- D06M11/36—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with oxygen, ozone, ozonides, oxides, hydroxides or percompounds; Salts derived from anions with an amphoteric element-oxygen bond with oxides, hydroxides or mixed oxides; with salts derived from anions with an amphoteric element-oxygen bond
- D06M11/45—Oxides or hydroxides of elements of Groups 3 or 13 of the Periodic System; Aluminates
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
- D06M11/51—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with sulfur, selenium, tellurium, polonium or compounds thereof
- D06M11/55—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with sulfur, selenium, tellurium, polonium or compounds thereof with sulfur trioxide; with sulfuric acid or thiosulfuric acid or their salts
- D06M11/57—Sulfates or thiosulfates of elements of Groups 3 or 13 of the Periodic System, e.g. alums
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
- D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
- D06M13/184—Carboxylic acids; Anhydrides, halides or salts thereof
- D06M13/192—Polycarboxylic acids; Anhydrides, halides or salts thereof
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
- D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
- D06M13/184—Carboxylic acids; Anhydrides, halides or salts thereof
- D06M13/207—Substituted carboxylic acids, e.g. by hydroxy or keto groups; Anhydrides, halides or salts thereof
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
- D06M15/01—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with natural macromolecular compounds or derivatives thereof
- D06M15/03—Polysaccharides or derivatives thereof
- D06M15/05—Cellulose or derivatives thereof
- D06M15/09—Cellulose ethers
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
- D06M15/01—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with natural macromolecular compounds or derivatives thereof
- D06M15/03—Polysaccharides or derivatives thereof
- D06M15/11—Starch or derivatives thereof
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
- D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
- D06M15/21—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D06M15/263—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds of unsaturated carboxylic acids; Salts or esters thereof
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M23/00—Treatment of fibres, threads, yarns, fabrics or fibrous goods made from such materials, characterised by the process
- D06M23/08—Processes in which the treating agent is applied in powder or granular form
-
- 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
-
- 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
- A61F13/534—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 an inhomogeneous composition through the thickness of the pad
- A61F13/537—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 an inhomogeneous composition through the thickness of the pad characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer
-
- 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
- A61F13/15203—Properties of the article, e.g. stiffness or absorbency
- A61F2013/15284—Properties of the article, e.g. stiffness or absorbency characterized by quantifiable properties
- A61F2013/15544—Permeability
-
- 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
-
- 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.]
- Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
-
- 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.]
- Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
- Y10T442/2484—Coating or impregnation is water absorbency-increasing or hydrophilicity-increasing or hydrophilicity-imparting
-
- 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.]
- Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
- Y10T442/2484—Coating or impregnation is water absorbency-increasing or hydrophilicity-increasing or hydrophilicity-imparting
- Y10T442/2492—Polyether group containing
-
- 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.]
- Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
- Y10T442/2508—Coating or impregnation absorbs chemical material other than water
-
- 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.]
- Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
- Y10T442/2762—Coated or impregnated natural fiber fabric [e.g., cotton, wool, silk, linen, etc.]
- Y10T442/277—Coated or impregnated cellulosic fiber fabric
-
- 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]
-
- 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]
- Y10T442/69—Autogenously bonded nonwoven fabric
-
- 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]
- Y10T442/696—Including strand or fiber material which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous compositions, water solubility, heat shrinkability, 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]
- Y10T442/699—Including particulate material other than strand or fiber material
Definitions
- the present invention relates to a fiber treated to enhance permeability of an absorbent structure prepared from such fibers. More particularly, the invention relates to fibers treated with polyvalent metal ion-containing compounds for use in absorbent structures made with such fibers, and absorbent articles containing such absorbent structures.
- Absorbent structures are important in a wide range of disposable absorbent articles including infant diapers, adult incontinence products, sanitary napkins and other feminine hygiene products and the like. These and other absorbent articles are generally provided with an absorbent core to receive and retain body liquids.
- the absorbent core is usually sandwiched between a liquid pervious topsheet, whose function is to allow the passage of fluid to the core and a liquid impervious backsheet whose function is to contain the fluid and to prevent it from passing through the absorbent article to the garment of the wearer of the absorbent article.
- An absorbent core for diapers, adult incontinence pads and feminine hygiene articles frequently includes fibrous batts or webs constructed of defiberized, loose, fluffed, hydrophilic, cellulosic fibers. Such fibrous batts form a matrix capable of absorbing and retaining some liquid. However, their ability to do so is limited. Thus, superabsorbent polymer (“SAP”) particles, granules, flakes or fibers (collectively “particles”), capable of absorbing many times their weight of liquid, are often included in the absorbent core to increase the absorbent capacity of the core, without having to substantially increase the bulkiness of the core. In an absorbent core containing matrix fibers and SAP particles, the fibers physically separate the SAP particles, provide structural integrity for the absorbent core, and provide avenues for the passage of fluid through the core.
- SAP superabsorbent polymer
- Absorbent cores containing SAP particles have been successful, and in recent years, market demand has increased for thinner, more absorbent and more comfortable absorbent articles. Such an article may be obtained by increasing the proportion of SAP particles to the cellulose or other matrix fibers in the absorbent core.
- One way to minimize gel block (and maintain core permeability) is to limit the proportion of SAP particles to matrix fibers in the absorbent core. In this way, there is sufficient separation between particles, such that even after the particles have been swollen by exposure to liquid they do not contact adjacent particles and free liquid can migrate to unexposed SAP particles.
- limiting the concentration of SAP particles in the absorbent core also limits the extent to which the core can be made thinner and more comfortable.
- commercial absorbent cores are presently limited to SAP particle concentrations of 20% to 50% by weight of the core.
- Modification of the superabsorbent polymer usually involves reducing the gel volume of the superabsorbent polymer particles by increasing the crosslinking of the polymer.
- a crosslinked SAP particle is restricted in its ability to swell, and therefore has a reduced capacity, or gel volume.
- modified SAP particles are less susceptible to gel block, they also absorb less liquid by weight due to their reduced gel volume. Modified SAP particles also tend to be brittle and fracture and crack during or after processing into the final absorbent product.
- crosslinkers are known in the art. It is also known to use polyvalent metal ions, including aluminum, during the manufacture of SAPs, to serve as an ionic crosslinking agent. See for example, U.S. Pat. No. 5,736,595.
- SAP particle permeability refers to the ability of liquid to permeate through an absorbent structure containing SAP particles. As used herein, such permeability is measured by methods including “vertical” permeability and “inclined” permeability. A core “permeability factor” may be determined from both vertical and inclined permeability measurements.
- a method for improved utilization of the superabsorber is disclosed in U.S. Pat. No. 5,147,343, where particle size distribution of the granules is controlled.
- the rate of fluid uptake can be optimized to the core design.
- the utilization of the absorbent core is reduced at higher concentrations of SAP particles due to gel blocking.
- the present invention is directed to absorbent structures including fibers bound with a polyvalent cation-containing compound and superabsorbent polymer particles.
- the fibers exhibit an ion extraction factor of at least 5%.
- the present invention is also directed to multi-strata absorbent structures, such as disposable absorbent articles, including the treated fibers and SAP particles.
- the present invention is also directed to methods for preparing absorbent structures including the treated fibers; structures including fibers combined with a polyvalent cation-containing compound; and methods for treating or coating SAP particles with polyvalent cation-containing compounds.
- FIG. 1 is a perspective view of an inclined permeability test apparatus employed in the Examples of the present specification.
- FIG. 2 is a graph illustrating the inclined permeability of absorbent structures of the present invention compared with conventional structures.
- FIG. 3 is a perspective view of a vertical permeability test apparatus employed in the Examples of the present specification.
- FIG. 4 is a graph illustrating vertical permeability of SAP-containing absorbent structures after application of 0.9% saline solution having various compounds dissolved in the saline at different concentrations.
- FIG. 5 is a graph illustrating vertical permeability of SAP-containing absorbent structures made with fibers treated with various compounds, or absorbent structures having various compounds applied to thereto.
- FIG. 6 is a graph illustrating the relationship between permeability factor and ion removal, for absorbent structures prepared according to the present invention.
- FIG. 7 is a graph illustrating the relationship between permeability factor and disposable diaper performance as measured by fluid wicked to diaper extremity, for absorbent structures prepared according to the present invention.
- FIG. 8 is a graph illustrating the relationship between permeability factor and absorbent structure performance, as measured by fluid wicked to structure extremity, for absorbent structures prepared according to the present invention.
- an absorbent structure made from such fibers and SAP particles exhibits reduced gel blocking and increased core permeability.
- concentration of SAP particles in an absorbent core may be increased without experiencing gel block or loss in permeability of the core. This allows for better utilization of the absorbent core, because a high fluid flow can be maintained under usage pressure in the absorbent core, thus enabling manufacturers to produce thinner, more absorbent and more comfortable absorbent structures.
- FIG. 8 exemplifies the improvement in absorbent cores as the permeability is increased.
- the fluid wicked to the core extremity refers to the last three inches of the core material as measured by the horizontal wicking test as described in the procedures section.
- an improvement in core utilization is noted.
- FIG. 7 shows that for machine-made diapers, the permeability improvement also provides an improvement in core utilization as measured by the horizontal wicking test.
- any compatible polyvalent metal ion-containing compound may be employed, provided that the compound releases the polyvalent metal ion upon exposure of the treated fiber to the liquid encountered in the core.
- the degree to which the polyvalent ion is released from the fiber upon exposure to liquid is referred to herein as “ion extraction”.
- the degree of “ion extraction” is related to the permeability of cores as illustrated in FIG. 6. In this figure increasing ion extraction provides increased permeability.
- the compound chemically bond with the fibers, although it is preferred that the compound remain associated in close proximity with the fibers, by coating, adhering, precipitation, or any other mechanism such that it is not dislodged from the fibers during normal handling of the fibers, absorbent core or absorbent article before contact with liquid.
- the association between the fiber and the compound discussed above may be referred to as the “bond,” and the compound may be said to be bound to the fiber.
- sheeted cellulosic fibers treated with a water insoluble aluminum compound had the same aluminum concentration before and after hammer mill disintegration (Kamas mill).
- Sheeted cellulosic fibers treated with a water soluble aluminum compound the same aluminum concentration before disintegration (Kamas mill) and after disintegration.
- Sheeted cellulosic fibers treated with a water insoluble and a water soluble aluminum compound had the same aluminum concentration before disintegration (Kamas mill) and after disintegration.
- any polyvalent metal salt including transition metal salts may be used, provided that the compound is capable of releasing the polyvalent metal ion upon contact with liquid encountered in the absorbent core.
- the polyvalent metal containing compound selected for this application should be compatible with safe contact with human skin and mucous membranes.
- suitable polyvalent metals include beryllium, magnesium, calcium, strontium, barium, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, aluminum and tin.
- Preferred ions include aluminum, iron and tin.
- the preferred metal ions have oxidation states of +3 or +4. The most preferred ion is aluminum.
- any salt containing the polyvalent metal ion may be employed, provided that the compound is capable of releasing the polyvalent metal ion upon contact with liquid encountered in the absorbent core.
- suitable inorganic salts of the above metals include chlorides, nitrates, sulfates, borates, bromides, iodides, fluorides, nitrides, perchlorates, phosphates, hydroxides, sulfides, carbonates, bicarbonates, oxides, alkoxides phenoxides, phosphites, and hypophosphites.
- suitable organic salts of the above metals include formates, acetates, butyrates, hexanoates, adipates, citrates, lactates, oxalates, propionates, salicylates, glycinates, tartrates, glycolates, sulfonates, phosphonates, glutamates, octanoates, benzoates, gluconates, maleates, succinates, and 4,5-dihydroxy-benzene-1,3-disulfonates.
- amines ethylenediaminetetra-acetic acid (EDTA), diethylenetriaminepenta-acetic acid (DTPA), nitrilotri-acetic acid (NTA), 2,4-pentanedione, and ammonia.
- EDTA ethylenediaminetetra-acetic acid
- DTPA diethylenetriaminepenta-acetic acid
- NTA nitrilotri-acetic acid
- 2,4-pentanedione 2,4-pentanedione
- FIG. 4 shows the effect of a variety of polyvalent metal containing compounds on vertical permeability of test cores containing SAP and cellulose fiber. This data indicates that several polyvalent metal cations produce a higher vertical permeability in the test core than the aluminum salts, when the polyvalent metal containing compounds are dissolved in the mobile phase (0.9% saline) of the vertical permeability test.
- FIG. 5 shows the effect of a variety of polyvalent metal containing compounds on the vertical permeability test cores containing SAP and cellulose fiber pretreated with the polyvalent metal salt, or test cores that are a mixture of SAP and cellulose fiber and the polyvalent metal salt.
- test cores containing the aluminum salts have superior vertical permeability to those containing other polyvalent metal containing compounds.
- preferred compounds are those which contain aluminum and are capable of releasing aluminum ions upon contact with liquid encountered in the absorbent core. Examples of such compounds include aluminum salts such as aluminum chloride, aluminum sulfate and aluminum hydroxide.
- the polyvalent metal ion containing compound used to treat the fiber it may be necessary to provide other components, to cause or enhance ionization when liquid contacts the treated fiber.
- the metal ion containing compound if aluminum hydroxide is employed as the metal ion containing compound, and is precipitated onto the hydrophilic fibers, it is necessary to also treat the fiber with an ionizable acid, for example citric acid.
- an ionizable acid for example citric acid.
- the treated fiber is exposed to liquid, such as urine for example, the liquid will solubilize the acid, reducing the pH of the liquid and thereby ionizing the aluminum hydroxide to provide aluminum ions in the form of aluminum citrate.
- acids may be employed, although the acid preferably should have a low volatility, be highly soluble in water, and bond to the fiber.
- suitable acids include inorganic acids such as sodium bisulfate and organic acids such as formic, acetic, aspartic, propionic, butyric, hexanoic, benzoic, gluconic, oxalic, malonic, succinic, glutaric, tartaric, maleic, malic, phthallic, sulfonic, phosphonic, salicylic, glycolic, citric, butanetetracarboxylic acid (BTCA), octanoic, polyacrylic, polysulfonic, polymaleic, and lignosulfonic acids, as well as hydrolyzed-polyacrylamide and CMC (carboxymethylcellulose).
- carboxylic acids acids with two carboxyl groups are preferred, and acids with three carboxyl groups are more preferred. Of these acids, citric acid is most preferred.
- the amount of acid employed is dictated by the acidity and the molecular weight of that acid. Generally it is found that an acceptable range of acid application is 0.5%-10% by weight of the fibers. As used herein, the “percent by weight,” refers to the weight percent of dry fiber treated with the polyvalent metal containing compound. For citric acid the preferred range of application is 0.5%-3% by weight of the fibers.
- the treatment of fibers with a polyvalent ion-containing compound increases core permeability.
- Such treatment results in stiffening of the fibers.
- the stiffened fibers do not swell in water to the extent that untreated fibers do. Consequently existing interfiber channels or other avenues for liquid to flow through an absorbent structure formed from the fibers are kept open to a greater extent by the stiffened fibers than by the untreated fibers.
- the reduction in wet swell that is produced by polyvalent ion treatment of the fibers represents an important contribution to the overall improved permeability of an absorbent core containing SAP particles and the treated fibers of the present invention.
- Water retention value is an indication of a fiber's ability to retain water under a given amount of pressure. Cellulose fibers that are soaked in water swell moderately, and physically retain water in the swollen fiber walls. When an aqueous fiber slurry is centrifuged, the majority of the water is removed from the fibers. However, a quantity of water is retained by the fiber even after centrifugation, and this quantity of water is expressed as a percentage based on the dry weight of the fiber. All of the fibers treated according to the present invention, have lower WRV values than corresponding untreated fibers. Consequently, all the treated fibers are stiffer than conventional fluff fibers, thus contribute to improved core permeability.
- reducing agents may be applied to the treated fibers to maintain desired levels of fiber brightness, by reducing brightness reversion. Addition of acidic substances may cause browning of fibers when heated during processing of webs containing the fibers. Reducing agents counter the browning of the fibers. The reducing agent should also bond to the fibers. Preferred agents are sodium hypophosphite and sodium bisulfite, and mixtures thereof.
- a wide variety of fiber types may be treated with the polyvalent metal ion containing compound.
- hydrophilic fibers for use in the present invention include cellulosic fibers, modified crosslinked cellulose fibers, rayon, polyester fibers, hydrophilic nylon, silk wool and the like.
- Suitable hydrophilic fibers can also be obtained by hydrophilizing hydrophobic fibers. Fibers may be hydrophilized by treatment with surfactants, silica, or surface oxidation, e.g. by ozone in a corona discharge.
- Such fibers may be derived from, for example, polyolefins such as polyethylene or polypropylene, polyacrylics, polyamides, polystyrenes, polyurethanes and the like.
- the preferred fiber is cellulose.
- suitable sources of cellulose fibers include softwood cellulose, hardwood cellulose, cotton, esparto grass, bagasse, hemp, flax, chemically modified cellulose and cellulose acetate.
- the preferred wood cellulose is bleached cellulose.
- the final purity of the preferred cellulose fiber of the present invention may range from at least 80% alpha to 98% alpha cellulose, although purity of greater than 95% alpha is preferred, and purity of 96.5% alpha cellulose, is most preferred.
- the term “purity” is measured by the percentage of alpha cellulose present. This is a conventional measurement in the dissolving pulp industry. Methods for the production of cellulose fiber of various purities typically used in the pulp and paper industry are known in the art.
- Curl is defined as a fractional shortening of the fiber due to kinks, twists and/or bends in the fiber.
- the percent curl of the cellulose fibers of the present invention is preferably from 25% to 80%, and is more preferably 75%.
- fiber curl may be measured in terms of a two dimensional field. The fiber curl is determined by viewing the fiber in a two dimensional plane, measuring the projected length of the fiber as the longest dimension of a rectangle encompassing the fiber, L (rectangle), and the actual length of the fiber L (actual), and then calculating the fiber curl factor from the following equation:
- a fiber curl index image analysis method is used to make this measurement and is described in U.S. Pat. No. 5,190,563. Fiber curl may be imparted by mercerization. Methods for the mercerization of cellulose typically used in the pulp and paper industry are known in the art.
- the preferred water retention value (WRV) of the cellulose fibers of the present invention is less than 85 %, and more preferably between 30% and 80%, and most preferably 40%.
- the WRV refers to the amount of water calculated on a dry fiber basis, that remains absorbed by a sample of fibers that has been soaked and then centrifuged to remove interfiber water. The amount of water a fiber can absorb is dependent upon its ability to swell on saturation. A lower number indicates internal cross-linking has taken place.
- U.S. Pat. No. 5,190,563 describes a method for measuring WRV.
- chemically stiffened cellulose fibers means cellulose fibers that have been treated to increase the stiffness of the fibers under both dry and wet aqueous conditions.
- chemical processing includes intrafiber crosslinking with crosslinking agents while such fibers are in a relatively dehydrated, defibrated (i.e., individualized), twisted, curled condition. These fibers are reported to have curl values greater than 70% and WRV values less than 60%. Fibers stiffened by crosslink bonds in individualized form are disclosed, for example U.S. Pat. No. 5,217,445 issued Jun. 8, 1993, and U.S. Pat. No. 3,224,926 issued Dec. 21, 1965.
- superabsorbent polymer particle or “SAP” particle is intended to include any particulate form of superabsorbent polymer, including irregular granules, spherical particles (beads), powder, flakes, staple fibers and other elongated particles.
- SAP refers to a normally water-soluble polymer which has been cross-linked to render it substantially water insoluble, but capable of absorbing at least ten, and preferably at least fifteen, times its weight of a physiological saline solution. Numerous examples of superabsorbers and their methods of preparation may be found for example in U.S. Pat. Nos.
- SAPs generally fall into three classes, namely starch graft copolymers, cross-linked carboxymethylcellulose derivatives and modified hydrophilic polyacrylates.
- Non-limiting examples of such absorbent polymers are hydrolyzed starch-acrylate graft co-polymer, saponified acrylic acid ester-vinyl co-polymer, neutralized cross-linked polyacrylic acid, cross-linked polyacrylate salt, and carboxylated cellulose.
- the preferred SAPs upon absorbing fluids, form hydrogels.
- Suitable SAPs yield high gel volumes or high gel strength as measured by the shear modulus of the hydrogel.
- Such preferred SAPs contain relatively low levels of polymeric materials that can be extracted by contact with synthetic urine (so-called “extractables”).
- SAPs are well known and are commercially available from several sources.
- IM1000TM Hoechst-Celanese, Portsmouth, Va.
- Suitable SAP particles for use in the present invention include those discussed above, and others, provided that the SAP particle provides improved permeability of an absorbent core made with the SAP and a hydrophilic fiber treated according to the present invention. Most preferred for use with the present invention are polyacrylate-based SAPs.
- SAP particles of any size or shape suitable for use in an absorbent core may be employed.
- the treated fibers of the present invention may be used in combination with SAP particles, to form a stratum of an absorbent core, useful in forming an absorbent structure for use in manufacturing an absorbent article.
- the treated fibers begin to show improved core permeability in a mixture of 20% SAP and 80% fiber in an absorbent core, even better permeability is displayed in a mixture of 40% SAP and 60% fiber in an absorbent core, and further improvement in permeability is observed in a mixture of 60% to 80% SAP and 40% to 20% fiber in an absorbent core.
- the treated fibers will be used to form one stratum of a multi-strata absorbent structure.
- Absorbent structures particularly useful in infant diapers and adult incontinence products often include at least two defined strata—an upper acquisition stratum and a lower storage stratum. Sometimes, a distribution stratum is provided between the acquisition and storage strata. Optionally, a wicking stratum is provided below the storage stratum.
- SAP particles are provided in the storage stratum, although such SAP particles may also, or alternatively be provided in a distribution stratum.
- the treated fibers or other treated substrates of the present invention may be located in any stratum, provided that upon exposure of the absorbent structure to a liquid insult, the liquid contacts the treated fiber, and then carries the polyvalent metal ion to the SAP particles.
- the treated fiber of the present invention will be provided in the storage layer.
- the treated fibers of the present invention may be employed in any disposable absorbent article intended to absorb and contain body exudates, and which are generally placed or retained in proximity with the body of the wearer.
- Disposable absorbent articles include infant diapers, adult incontinence products, training pants, sanitary napkins and other feminine hygiene products.
- a conventional disposable infant diaper generally includes a front waistband area, a rear waistband area and a crotch region there between.
- the structure of the diaper generally includes a liquid pervious topsheet, a liquid impervious backsheet, an absorbent structure, elastic members, and securing tabs.
- Representative disposable diaper designs may be found, for example in U.S. Pat. No. 4,935,022 and U.S. Pat. No. 5,149,335.
- U.S. Pat. No. 5,961,505 includes representative designs for feminine hygiene pads.
- the absorbent structure incorporating the treated fibers of the present invention may be formed in place by blending individualized fibers and SAP particles and applying them to a form under applied vacuum to create an absorbent structure of desired shape.
- the absorbent structure may be formed separately as a continuous roll good, preferably using airlaid (or “dryformed”) technology.
- the fibers suitable for use in absorbent structures may be treated in a variety of ways to provide the polyvalent metal ion-containing compound in close association with the fibers.
- a preferred method is to introduce the compound in solution with the fibers in slurry form and cause the compound to precipitate onto the surface of the fibers.
- the fibers may be sprayed with the compound in aqueous or non-aqueous solution or suspension.
- the fibers may be treated while in an individualized state, or in the form of a web.
- the compound may be applied directly onto the fibers in powder or other physical form.
- the compound remain bound to the fibers, such that the compound is not dislodged during normal physical handling of the fiber in forming the absorbent structure and absorbent articles or use of the article, before contact of the fiber with liquid.
- the applied compound should be released from the fiber to provide ions within the liquid.
- the treated fibers of the present invention are made from cellulose fiber, obtained from Buckeye Technologies Inc. (Memphis, Tennessee). The pulp is slurried, the pH is adjusted to about 4.0, and aluminum sulfate (Al 2 (SO 4 ) 3 ) in aqueous solution is added to the slurry. The slurry is stirred and the consistency reduced. Under agitation, the pH of the slurry is increased to approximately 5.7. The fibers are then formed into a web or sheet, dried, and sprayed with a solution of citric acid at a loading of 2.5 weight % of the fibers.
- Al 2 (SO 4 ) 3 aluminum sulfate
- the web is then packaged and shipped to end users for further processing, including fiberization to form individualized fibers useful in the manufacture of absorbent products.
- a reducing agent is to be applied, preferably it is applied before a drying step and following any other application steps.
- the reducing agent may be applied by spraying, painting or foaming.
- the soluble Al 2 (SO 4 ) 3 introduced to the pulp slurry is converted to insoluble Al(OH) 3 as the pH is increased.
- the insoluble aluminum hydroxide precipitates onto the fiber.
- the resultant fibers are coated with Al(OH) 3 or contain the insoluble metal within the fiber interior.
- the citric acid sprayed on the web containing the fibers dries on the fibers.
- the citric acid creates a locally acidic environment when the citric acid-treated fibers of the absorbent product are exposed to a liquid insult (e.g., urine).
- the decreased pH created by the acid environment converts the Al(OH) 3 to the soluble form of aluminum including a citric acid complex of this metal.
- aluminum ions may become available in solution to locally and temporarily inhibit the swelling of superabsorbent polymers (also present in the absorbent material) thereby minimizing or preventing gel-blocking.
- the above procedure is followed to treat the fibers with precipitated Al(OH) 3 , and in a subsequent step, aluminum sulfate is applied, preferably by spraying, onto the Al(OH) 3 -treated fibers.
- aluminum sulfate is applied to the web, before the web is introduced to web dryers.
- Application to the wet web provides better distribution of the aluminum sulfate through the web.
- the acidic environment provided by the aluminum sulfate is also conducive to release of soluble aluminum ions from the Al(OH) 3 precipitate.
- a hierarchy of preferred embodiments is exemplified as follows: a two component mixture of (1) cellulosic fibers pretreated with a water soluble aluminum compound and (2) SAP particles in an absorbent core (Example 4), provides a higher level of core permeability than a comparable three component mixture of (1) cellulosic fibers and (2) a water soluble aluminum compound and (3) SAP particles in an absorbent core (Example 12), and a higher level of core permeability than a two component mixture of (1) SAP particles pretreated with a water soluble aluminum compound in an aqueous solution and (2) cellulosic fibers in an absorbent core (Example 15).
- Improved core permeability may be obtained by coating the surface of SAP particles with a polyvalent ion salt, and combining the coated SAP particle with a fiber in an absorbent structure.
- the particles are coated in contrast to reacting or complexing the SAP particles with a polyvalent cation salt.
- Coating of the SAP particle with the salt is accomplished by mixing the SAP particles with a non-aqueous solution of the polyvalent ion salt, and subsequently removing the non-aqueous solvent, leaving a coating of the salt on the surface of the SAP particle.
- an anhydrous methanol solution of aluminum sulfate may be mixed with SAP particles at room temperature, for example FavorTM SXM 9100, the mixture dried, and the granular coated SAP particles mixed with fluff fiber in an absorbent core.
- the core permeability for such a structure is much higher than that obtained when an equivalent amount of polyvalent ion salt in aqueous solution is used to treat SAP particles, indicating superior core permeability with aluminum sulfate-coated particles compared to aluminum cation-complexed SAP particles.
- methanol is the preferred non-aqueous solvent, any solvent which dissolves the salt but does not swell the SAP particle, may be used. Examples include alcohols, such as ethanol, n-propanol, iso-propanol and acetone.
- a Kamas mill (Kamas Industri AB, Sweden) is used to disintegrate pulp sheets into fluff pulp.
- a pad former (Buckeye Technologies, Memphis, Tenn.) is used to combine the fluff and SAP particles.
- Laboratory air-laid absorbent structures are made by combining fiber and SAP particles in the laboratory to simulate the process of an absorbent core construction on a full-scale commercial line. Fiber and SAP particles are loaded into the pad former. Fiber and SAP particles are combined through air vortices and become one single structure via the applied vacuum. The air-laid structure is then die-cut to dimensions specific for performance testing. For testing purposes, the airlaid structure should have dimensions of 14′′ ⁇ 14′′ at a target basis weight (0.30 g/in 2 or 0.22 g/in 2 ).
- Metal ion content, including aluminum or iron content, in pulp samples is determined by wet ashing (oxidizing) the sample with nitric and perchloric acids in a digestion apparatus. A blank is oxidized and carried through the same steps as the sample. The sample is then analyzed using an inductively coupled plasma spectrophotometer (“ICP”) (e.g., a Perkin-Elmer ICP 6500). From the analysis, the ion content in the sample can be determined in parts per million.
- ICP inductively coupled plasma spectrophotometer
- the polyvalent cation content should be between 0.25% and 5.0% by weight of fibers, preferably between 0.25% and 2.5% by weight of fibers, and more preferably between 0.4% and 1.2% by weight of fibers.
- the percentage of ions extracted from fibers in a saline solution is measured by submerging the test fibers in a saline solution that is shaken for 24 hours. During this period, ions are extracted from the fibers and into the solution. The ion concentration in the solution is measured using an ICP and compared with the ion content in the original fiber sample to determine the percentage of ion removed due to prolonged exposure to saline under agitation. The ion extraction should exceed 5%, preferably exceed 25%, more preferably exceed 50%, and most preferably exceed 90%.
- a Kamas Cell Mill (Kamas Industri AB, Sweden) apparatus is used to form disintegrated pulp sheets that in turn are used to produce fluff.
- a pad former (Buckeye Technologies Inc., Memphis, Tenn.) is used to combine SAP particles and fiber to prepare 14′′ ⁇ 14′′ test pads. Test pads are constructed at a basis weight of 0.3 g/in 2 and pressed to a density of 0.15 g/cc. Samples are die-cut to 21 ⁇ 4′′ diameter circles and conditioned before testing. The circles are dried in a forced air oven, then placed in a dessicator until the permeability test is run. The sample is then positioned into a vertical cylinder that contains a base (sample platform) constructed from wire mesh. See FIG.
- the vertical cylinder has an inside diameter of 21 ⁇ 4′′.
- a weight placed onto the sample supplies about 0.3 lb/in 2 of pressure perpendicular to the sample.
- the sample is saturated in fluid (0.9% saline) for one hour.
- the vertical cylinder containing the sample is secured over (but not in contact with) a weighing balance.
- the sample is initially insulted with 50 ml of 0.9% saline via a 3 ⁇ 8′′ hole centered in the weight.
- a 25-ml insult is added for every 25 grams of fluid that transferred to the balance until the balance reads 100 grams. Fluid transferred by the sample is measured per unit of time to quantify the permeability for a given sample. Absorption capacity for the samples is also recorded.
- Permeability samples are placed on a Teflon coated block inclined at a 45-degree angle. Attached to this block is a fluid head box connected by 1 ⁇ 4′′ tubing to a vertically adjustable fluid reservoir. The front edge of the sample pad is centered onto and secured to the head box. The head box is designed with three ⁇ fraction (3/16) ⁇ ′′ diameter holes that are spaced ⁇ fraction (9/16) ⁇ ′′ apart.
- a top block coated with Teflon, with a congruent 45-degree angle, is placed on top of the sample pad. Lubricated pegs are inserted into the bottom block (sample platform) at a 60-degree angle to prevent the top block from slipping while allowing for uniform sample expansion after saturation.
- a 724.4 g weight, along with the weight of the top block supplies about 0.3 lbs/in 2 of pressure perpendicular to the sample.
- the fluid (0.9% saline) level is adjusted to produce and maintain an inverted meniscus.
- the sample pad acts as a siphon by transferring fluid to a tared receiving container atop a balance located below the end of the sample. Liquid transferred by the sample is measured per unit time to establish a flow rate. Permeability for a given sample is quantified after the flow rate reaches equilibrium.
- FIG. 2 shows the incline permeability at various time intervals for 50% SAP and 50% cellulose fiber mixtures, and 70% SAP and 30% cellulose fiber mixtures.
- the figure also shows the increased permeability produced by the invention fiber in a mixture with SAP (Example 3).
- the permeability factor is determined by summing the permeability in gm/min from the vertical permeability and the inclined permeability. The sum is taken as follows:
- Horizontal wicking samples of about 4′′ ⁇ 14′′ are placed onto a level platform with bordering grooves to capture “runoff” fluid (0.9% saline).
- Both laboratory test cores or manufactured diaper cores may be used.
- an acquisition-distribution layer (ADL) from a commercial diaper cut to 3′′ ⁇ 7′′ is placed on top of the sample where fluid is introduced.
- ADL acquisition-distribution layer
- the top board contained an insult reservoir with a ⁇ fraction (11/2) ⁇ ′′ inside diameter. The insult region, relative to the sample, was 5′′ centered from the front end or end closest to the insult reservoir. Two 10 lb.
- weights placed on the top board along with the weight of the top board supplied about 0.40 lbs/in 2 of pressure perpendicular to the sample.
- a slurry of bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies consisting of 4.5 parts fiber/100 parts slurry was diluted with sufficient water to provide 0.9 parts fiber/100 parts slurry and adjusted to a pH of 5.5.
- the resultant slurry was continuously dewatered on a sheeting machine where a sheet was formed at rush/drag ratio of 1.0, couched, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry.
- the sheet was dried using conventional drum dryers to 93.5 percent solids. The sheet was reeled on a continuous roll.
- Sheets from the roll were defiberized in a Kamas mill. An ion extraction test was performed on the fibers as described above. The ionic extraction of the fiber was measured at 0%. Vertical and inclined permeability tests were performed as described above using test cores that were a mixture of 70% by weight of SAP particles and 30% by weight of fibers. The permeability factor was then calculated. When FAVORTM SXM 70 SAP (obtained from Stockhausen, Inc.) was used, a permeability factor of 16 was obtained.
- Comparative Example 1 was repeated, except that SAP FAVORTM SXM 9100 was used instead of FAVORTM SXM 70.
- the permeability factor obtained was 141.
- Cellulose fibers were treated as follows. A total of 9.36 parts hydrated aluminum sulfate (Al 2 (SO 4 ) 3 *14 H 2 O) from General Chemical Corporation, per 100 parts bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies were added to a slurry consisting 4.5 parts fiber/100 parts slurry. The slurry had a pH of 3.2. After 25 minutes of mixing 3.0 parts sodium hydroxide/100 parts fiber were added along with sufficient water to provide 0.9 parts fiber/100 parts slurry at a pH of 5.7. The temperature was adjusted to 60° C.
- BSSK bleached southern softwood Kraft
- the resultant slurry was continuously dewatered on a sheeting machine where the sheet was formed at 1.0 rush/drag ratio, couched, then pressed and densified using three stages of pressing to 48 parts fiber/100 parts total.
- the sheet was dried using conventional drum dryers to 93.5 percent solids. While continuously reeling, a spray of 50% citric acid solution was applied to one surface of the sheet at a loading of 2.5 parts per 100 parts of fiber. The reeled sheet was then sized into individual rolls.
- the sheet was defiberized in a Kamas mill, and the ionic extraction test described above was performed.
- the fiber was found to have an ionic extraction of 34% and an aluminum content of approximately 7,500 ppm.
- Vertical and inclined permeability tests were performed on test cores using a mixture of 70% by weight of SAP particles and 30% by weight of fibers.
- the permeability factor using FAVORTM SXM 70 SAP was 31.
- Example 1 was repeated except that the SAP used was FAVORTM SXM 9100.
- the permeability factor obtained was 177.
- a slurry of bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies consisting of 4.5 parts fiber/100 parts slurry was diluted with sufficient water to provide 0.9 parts fiber/100 parts slurry and adjusted to a pH of 5.5.
- the resultant slurry was continuously dewatered on a sheeting machine and a sheet was formed at a rush/drag ratio of 1.0, couched, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry.
- the sheet was dried using conventional drum dryers to 93.5 percent solids. The sheet was then reeled.
- Example 3 was repeated except that the aluminum content of the fibers was 5445 ppm, and the SAP used was FAVORTM SXM 9100.
- the permeability factor obtained was 212.
- the ion extraction was 86%.
- sample sheet was defiberized in a Kamas mill as described above. Permeability was determined on test cores formed as described above, that were a mixture of FAVORTM SXM 9100, at 70% by weight and fiber 30% by weight. The permeability factor was calculated to be 178.
- the resultant slurry was continuously dewatered on a sheeting machine and a sheet formed at a 1.0 rush/drag ratio, couched, then pressed and densified using three stages of pressing to 48 parts fiber/100 parts total.
- the sheet was dried to 93.5 percent solids.
- To this sheet sample was applied three parts 1,2,3,4-butanetetracarboxylic acid (BTCA) from Aldrich Chemical Company per 100 parts of fiber by spraying a solution.
- BTCA 1,2,3,4-butanetetracarboxylic acid
- the sheet was defiberized in a Kamas mill and the fiber was determined to have an ionic extraction of 12.4%. All permeability factor testing was performed using pads made with 70% by weight of FAVORTM SXM 70 SAP and 30% weight of fiber. The permeability factor was determined to be 38.
- the resultant slurry was continuously dewatered on a sheeting machine and a sheet formed at a 1.0 rush/drag ratio, couched, then pressed and densified using three stages of pressing to 48 parts fiber/100 parts total.
- the sheet was dried to 93.5 percent solids.
- PTSA para-toluenesulfonic acid
- the sheet was defiberized in a Kamas mill and the fiber was determined to have an ionic extraction of 13.4%. All permeability factor testing was performed using test cores made with 70% by weight of FAVORTM SXM 70 SAP and 30% by weight of fiber. The permeability factor was determined to be 32.
- High porosity commercial fiber was obtained from Buckeye Technologies Inc. in sheet form.
- the fibers had a WRV of 78.7, a curl of 51% and a 96.5% alpha cellulose content.
- a total of 7.7 parts of hydrated aluminum sulfate octadecahydrate (Aldrich Chemical Company) per 100 parts fiber were applied to the sheeted material by spraying.
- High purity commercial cotton fiber (GR702) was obtained from Buckeye Technologies Inc. in sheet form. A total of 7.7 parts of aluminum sulfate octadecahydrate per 100 parts fiber were applied to the sheeted material by spraying. Ion extraction was measured for the fiber as 99.0%. Permeability was measured after preparing a pad that was 30% by weight of fibers and 70% by weight of FAVORTM SXM 9100 SAP. The permeability factor was 219.
- Fibers were prepared as disclosed in U.S. Pat. No. 5,190,563 by applying 4.7% citric acid and 1.6% sodium hypophosphite to a Southern Softwood Kraft pulp sheet. After individualizing and curing at 340° F. for 7.5 minutes, the pulp had a WRV of 44 and a curl of about 75%.
- the individualized fibers were treated by spraying 3.42 parts of hydrated aluminum sulfate (Al 2 (SO 4 ) 3 *14 H 2 O) per 100 parts fiber were added to the fibers and the fibers allowed to dry. The ionic extraction for the fibers was measured at 49.8%.
- the aluminum content of the fibers was measured at 10,869 ppm. Test pads were made with 30% by weight of the treated fibers and 70% by weight FAVORTM SXM 9100 SAP and the permeability factor measured. The factor was found to be 231.
- Test pads were made from 30% by weight bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies and 70% by weight FAVORTM SXM 9100 SAP, with the treated non-woven material as a topsheet, and the permeability factor measured. The permeability factor was 191.
- An absorbent core of improved permeability was prepared by adding 2.4 parts of aluminum sulfate octadecahydrate (51.3% aluminum sulfate) in powder form to 100 parts of a 30% by weight fiber and 70% by weight SAP core as described in the method for producing cores.
- the permeability factor with FAVORTM SXM 9100 at 70% SAP was 207.
- a slurry of bleached southern softwood Kraft (BSSK) fibers Buckeye Technologies consisting of 4.5 parts fiber/100 parts slurry was diluted with sufficient water to provide 0.9 parts fiber/100 parts slurry and adjusted to a pH of 5.5.
- the resultant slurry was continuously dewatered on a sheeting machine where the sheet was formed at a rush/drag ratio of 1.0, couched, then treated by spraying with 12.35 parts of hydrated aluminum sulfate and 3.17 parts of sodium hypophosphite per one hundred parts of fiber, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry.
- the sheet was dried using conventional drum dryers to 93.5 percent solids.
- the fiber was reeled on a continuous roll. The resultant reel was sized into individual rolls.
- the sheets were defiberized in a Kamas mill and the ionic extraction of the fiber was measured at 95%.
- the permeability factor was determined to be 216, using at test core that was 30% by weight fiber and 70% by weight FAVORTM SXM 9100.
- a total of 9.36 parts of hydrated aluminum sulfate (Al 2 (SO 4 ) 3 *14 H 2 O) per 100 parts of bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies were added to a slurry consisting of 4.5 parts fiber/100 parts slurry.
- the slurry had a pH of 3.2.
- 3.0 parts of sodium hydroxide per 100 parts of fiber were added with sufficient water to provide 0.9 parts fiber per 100 parts slurry at a pH of 5.7 and at a temperature of 60° C.
- the resultant slurry was continuously dewatered on a sheeting machine where the sheet was formed at a rush/drag ratio of 1.0, couched, then treated by spraying with 12.35 parts of hydrated aluminum sulfate and 3.17 parts of sodium hypophosphite per one hundred parts of fiber, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry.
- the sheet was dried using conventional drum dryers to 93.5 percent solids.
- the fiber was reeled on a continuous roll. The resultant reel was sized into individual rolls.
- the sheets were defiberized in a Kamas mill and the ionic extraction of the fiber was measured at 38.2% and the aluminum content was 9475 ppm.
- the permeability factor was determined to be 213, using a test core that was 30% by weight fiber and 70% by weight FAVORTM SXM 9100.
- An absorbent core was prepared by combining three parts of defiberized fluff fiber by weight with seven parts by weight of pretreated FAVORTM SXM 9100 SAP.
- the FAVORTM SXM 9100 SAP had been pretreated with aqueous aluminum sulfate octadecahydrate at ratio of 3.7 parts of dry aluminum sulfate octadecahydrate to 100 parts of SAP, dried at 125° C. for 3 hours, crushed and sieved to the same particle size as the untreated SAP.
- the permeability factor for this core was determined to be 187.
- An absorbent core was prepared by combining three parts of defiberized fluff fiber by weight with seven parts by weight of pretreated FAVORTM SXM 9100 SAP.
- the FAVORTM SXM 9100 SAP had been pretreated with a methanol solution of aluminum sulfate octadecahydrate at a ratio of 3.7 parts of dry aluminum sulfate octadecahydrate to 100 parts of SAP, air dried in an exhaust hood to remove visible liquid, and oven dried at 40° C. for two hours.
- the permeability factor for this core was determined to be 268.
Abstract
Description
- This application is a continuation application of U.S. patent application Ser. No. 10/360,147, filed Feb. 7, 2003, which is a divisional application of U.S. patent application Ser. No. 09/469,930, filed Dec. 21, 1999, which has issued into U.S. Pat. No. 6,562,743, which claims priority under 35 U.S.C. § 119, based on U.S. Provisional Application Ser. No. 60/117,565, filed Jan. 27, 1999, and Provisional Application Ser. No. 60/113,849, filed Dec. 24, 1998, the entire disclosures of which are hereby incorporated by reference.
- The present invention relates to a fiber treated to enhance permeability of an absorbent structure prepared from such fibers. More particularly, the invention relates to fibers treated with polyvalent metal ion-containing compounds for use in absorbent structures made with such fibers, and absorbent articles containing such absorbent structures.
- Absorbent structures are important in a wide range of disposable absorbent articles including infant diapers, adult incontinence products, sanitary napkins and other feminine hygiene products and the like. These and other absorbent articles are generally provided with an absorbent core to receive and retain body liquids. The absorbent core is usually sandwiched between a liquid pervious topsheet, whose function is to allow the passage of fluid to the core and a liquid impervious backsheet whose function is to contain the fluid and to prevent it from passing through the absorbent article to the garment of the wearer of the absorbent article.
- An absorbent core for diapers, adult incontinence pads and feminine hygiene articles frequently includes fibrous batts or webs constructed of defiberized, loose, fluffed, hydrophilic, cellulosic fibers. Such fibrous batts form a matrix capable of absorbing and retaining some liquid. However, their ability to do so is limited. Thus, superabsorbent polymer (“SAP”) particles, granules, flakes or fibers (collectively “particles”), capable of absorbing many times their weight of liquid, are often included in the absorbent core to increase the absorbent capacity of the core, without having to substantially increase the bulkiness of the core. In an absorbent core containing matrix fibers and SAP particles, the fibers physically separate the SAP particles, provide structural integrity for the absorbent core, and provide avenues for the passage of fluid through the core.
- Absorbent cores containing SAP particles have been successful, and in recent years, market demand has increased for thinner, more absorbent and more comfortable absorbent articles. Such an article may be obtained by increasing the proportion of SAP particles to the cellulose or other matrix fibers in the absorbent core.
- However, there are practical limits to increasing the proportion of SAP particles in the absorbent core. If the concentration of SAP particles in an absorbent core is too high, gel blocking can result. When SAP particles distributed through an absorbent core of matrix fibers are exposed to liquid they swell as they absorb the liquid, forming a gel. As adjacent SAP particles swell, they form a barrier to free liquid not immediately absorbed by the SAP particles. As a result, access by the liquid to unexposed SAP particles may be blocked by the swollen (gelled) SAP particles. When gel blocking occurs, liquid pooling, as opposed to absorption, takes place in the core. As a result, large portions of the core remain unused, and failure (leaking) of the absorbent core can occur. Gel blocking caused by high concentrations of SAP particles results in reduced core permeability, or fluid flow, under pressures encountered during use of the absorbent product.
- One way to minimize gel block (and maintain core permeability) is to limit the proportion of SAP particles to matrix fibers in the absorbent core. In this way, there is sufficient separation between particles, such that even after the particles have been swollen by exposure to liquid they do not contact adjacent particles and free liquid can migrate to unexposed SAP particles. Unfortunately, limiting the concentration of SAP particles in the absorbent core also limits the extent to which the core can be made thinner and more comfortable. To avoid gel block, commercial absorbent cores are presently limited to SAP particle concentrations of 20% to 50% by weight of the core.
- It would be highly desirable to provide an absorbent core capable of bearing a SAP particle concentration exceeding 50% by weight, preferably 50% to 80% by weight, while maintaining core permeability and avoiding the problem of gel block. It would also be desirable to provide an absorbent core, which exhibits improved permeability for a given SAP concentration. At the same time, it is important to be able to blend the matrix fiber and SAP particles into an absorbent core using conventional material shipping and handling processes to provide attractive economics for the manufacture of infant diapers, feminine hygiene pads, adult incontinence pads, and the like.
- Other methods for increasing SAP particle concentrations while minimizing gel block, have been directed to modifying the superabsorbent polymer itself. Modification of the superabsorbent polymer usually involves reducing the gel volume of the superabsorbent polymer particles by increasing the crosslinking of the polymer. A crosslinked SAP particle is restricted in its ability to swell, and therefore has a reduced capacity, or gel volume. Although modified SAP particles are less susceptible to gel block, they also absorb less liquid by weight due to their reduced gel volume. Modified SAP particles also tend to be brittle and fracture and crack during or after processing into the final absorbent product. A variety of crosslinkers are known in the art. It is also known to use polyvalent metal ions, including aluminum, during the manufacture of SAPs, to serve as an ionic crosslinking agent. See for example, U.S. Pat. No. 5,736,595.
- Crosslinking of SAP particles affects the permeability of the particle, i.e., the ability of liquid to permeate the particle to the center, thereby fully utilizing the capacity of the SAP particle. As used in this specification, SAP particle permeability is distinguished from the permeability of the “core” or absorbent structure. Core permeability refers to the ability of liquid to permeate through an absorbent structure containing SAP particles. As used herein, such permeability is measured by methods including “vertical” permeability and “inclined” permeability. A core “permeability factor” may be determined from both vertical and inclined permeability measurements.
- A method for improved utilization of the superabsorber is disclosed in U.S. Pat. No. 5,147,343, where particle size distribution of the granules is controlled. By controlling the particle size of the superabsorber and hence the surface area, the rate of fluid uptake can be optimized to the core design. However, the utilization of the absorbent core is reduced at higher concentrations of SAP particles due to gel blocking.
- The present invention is directed to absorbent structures including fibers bound with a polyvalent cation-containing compound and superabsorbent polymer particles. The fibers exhibit an ion extraction factor of at least 5%. The present invention is also directed to multi-strata absorbent structures, such as disposable absorbent articles, including the treated fibers and SAP particles.
- The present invention is also directed to methods for preparing absorbent structures including the treated fibers; structures including fibers combined with a polyvalent cation-containing compound; and methods for treating or coating SAP particles with polyvalent cation-containing compounds.
- FIG. 1 is a perspective view of an inclined permeability test apparatus employed in the Examples of the present specification.
- FIG. 2 is a graph illustrating the inclined permeability of absorbent structures of the present invention compared with conventional structures.
- FIG. 3 is a perspective view of a vertical permeability test apparatus employed in the Examples of the present specification.
- FIG. 4 is a graph illustrating vertical permeability of SAP-containing absorbent structures after application of 0.9% saline solution having various compounds dissolved in the saline at different concentrations.
- FIG. 5 is a graph illustrating vertical permeability of SAP-containing absorbent structures made with fibers treated with various compounds, or absorbent structures having various compounds applied to thereto.
- FIG. 6 is a graph illustrating the relationship between permeability factor and ion removal, for absorbent structures prepared according to the present invention.
- FIG. 7 is a graph illustrating the relationship between permeability factor and disposable diaper performance as measured by fluid wicked to diaper extremity, for absorbent structures prepared according to the present invention.
- FIG. 8 is a graph illustrating the relationship between permeability factor and absorbent structure performance, as measured by fluid wicked to structure extremity, for absorbent structures prepared according to the present invention.
- All patents, patent applications, and publications cited in this specification are hereby incorporated by reference in their entirety. In case of conflict in terminology, the present disclosure controls.
- It has now been surprisingly and unexpectedly discovered that by treating fibers with a polyvalent ion-containing compound, an absorbent structure (or core) made from such fibers and SAP particles exhibits reduced gel blocking and increased core permeability. As a result, the concentration of SAP particles in an absorbent core may be increased without experiencing gel block or loss in permeability of the core. This allows for better utilization of the absorbent core, because a high fluid flow can be maintained under usage pressure in the absorbent core, thus enabling manufacturers to produce thinner, more absorbent and more comfortable absorbent structures.
- FIG. 8 exemplifies the improvement in absorbent cores as the permeability is increased. In the figure, the fluid wicked to the core extremity refers to the last three inches of the core material as measured by the horizontal wicking test as described in the procedures section. For two types of SAP, an improvement in core utilization is noted. Further, FIG. 7 shows that for machine-made diapers, the permeability improvement also provides an improvement in core utilization as measured by the horizontal wicking test.
- When an absorbent core made with SAP particles and fibers treated with a polyvalent metal-ion containing compound according to the present invention is exposed to liquid, the polyvalent metal ion is released from the fibers, carried by the liquid and contacts the surface of the SAP particle. The polyvalent metal ion inhibits the rate of swelling of the SAP particle sufficiently to enable liquid to permeate beyond the swelling SAP particles to contact unexposed SAP particles. Although the rate of swelling is reduced, the extent of swelling of the SAP particles is not significantly affected by contact with liquid containing the polyvalent metal ion.
- To prepare fibers suitable for use in an absorbent core, any compatible polyvalent metal ion-containing compound may be employed, provided that the compound releases the polyvalent metal ion upon exposure of the treated fiber to the liquid encountered in the core. The degree to which the polyvalent ion is released from the fiber upon exposure to liquid is referred to herein as “ion extraction”. The degree of “ion extraction” is related to the permeability of cores as illustrated in FIG. 6. In this figure increasing ion extraction provides increased permeability.
- It is not necessary that the compound chemically bond with the fibers, although it is preferred that the compound remain associated in close proximity with the fibers, by coating, adhering, precipitation, or any other mechanism such that it is not dislodged from the fibers during normal handling of the fibers, absorbent core or absorbent article before contact with liquid. For convenience, the association between the fiber and the compound discussed above may be referred to as the “bond,” and the compound may be said to be bound to the fiber.
- This concept is exemplified as follows: sheeted cellulosic fibers treated with a water insoluble aluminum compound had the same aluminum concentration before and after hammer mill disintegration (Kamas mill). Sheeted cellulosic fibers treated with a water soluble aluminum compound the same aluminum concentration before disintegration (Kamas mill) and after disintegration. Sheeted cellulosic fibers treated with a water insoluble and a water soluble aluminum compound had the same aluminum concentration before disintegration (Kamas mill) and after disintegration.
- Any polyvalent metal salt including transition metal salts may be used, provided that the compound is capable of releasing the polyvalent metal ion upon contact with liquid encountered in the absorbent core. The polyvalent metal containing compound selected for this application should be compatible with safe contact with human skin and mucous membranes. Examples of suitable polyvalent metals include beryllium, magnesium, calcium, strontium, barium, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, aluminum and tin. Preferred ions include aluminum, iron and tin. The preferred metal ions have oxidation states of +3 or +4. The most preferred ion is aluminum. Any salt containing the polyvalent metal ion may be employed, provided that the compound is capable of releasing the polyvalent metal ion upon contact with liquid encountered in the absorbent core. Examples of suitable inorganic salts of the above metals include chlorides, nitrates, sulfates, borates, bromides, iodides, fluorides, nitrides, perchlorates, phosphates, hydroxides, sulfides, carbonates, bicarbonates, oxides, alkoxides phenoxides, phosphites, and hypophosphites. Examples of suitable organic salts of the above metals include formates, acetates, butyrates, hexanoates, adipates, citrates, lactates, oxalates, propionates, salicylates, glycinates, tartrates, glycolates, sulfonates, phosphonates, glutamates, octanoates, benzoates, gluconates, maleates, succinates, and 4,5-dihydroxy-benzene-1,3-disulfonates. In addition to the polyvalent metal salts, other compounds such as complexes of the above salts include amines, ethylenediaminetetra-acetic acid (EDTA), diethylenetriaminepenta-acetic acid (DTPA), nitrilotri-acetic acid (NTA), 2,4-pentanedione, and ammonia.
- It has been surprisingly discovered that trivalent aluminum ions are the preferred polyvalent metal ions for minimizing gel block. FIG. 4 shows the effect of a variety of polyvalent metal containing compounds on vertical permeability of test cores containing SAP and cellulose fiber. This data indicates that several polyvalent metal cations produce a higher vertical permeability in the test core than the aluminum salts, when the polyvalent metal containing compounds are dissolved in the mobile phase (0.9% saline) of the vertical permeability test. FIG. 5 shows the effect of a variety of polyvalent metal containing compounds on the vertical permeability test cores containing SAP and cellulose fiber pretreated with the polyvalent metal salt, or test cores that are a mixture of SAP and cellulose fiber and the polyvalent metal salt. This data indicates that the test cores containing the aluminum salts have superior vertical permeability to those containing other polyvalent metal containing compounds. Accordingly, preferred compounds are those which contain aluminum and are capable of releasing aluminum ions upon contact with liquid encountered in the absorbent core. Examples of such compounds include aluminum salts such as aluminum chloride, aluminum sulfate and aluminum hydroxide.
- Depending on the polyvalent metal ion containing compound used to treat the fiber, it may be necessary to provide other components, to cause or enhance ionization when liquid contacts the treated fiber. For example, if aluminum hydroxide is employed as the metal ion containing compound, and is precipitated onto the hydrophilic fibers, it is necessary to also treat the fiber with an ionizable acid, for example citric acid. When the treated fiber is exposed to liquid, such as urine for example, the liquid will solubilize the acid, reducing the pH of the liquid and thereby ionizing the aluminum hydroxide to provide aluminum ions in the form of aluminum citrate. A variety of suitable acids may be employed, although the acid preferably should have a low volatility, be highly soluble in water, and bond to the fiber. Examples include inorganic acids such as sodium bisulfate and organic acids such as formic, acetic, aspartic, propionic, butyric, hexanoic, benzoic, gluconic, oxalic, malonic, succinic, glutaric, tartaric, maleic, malic, phthallic, sulfonic, phosphonic, salicylic, glycolic, citric, butanetetracarboxylic acid (BTCA), octanoic, polyacrylic, polysulfonic, polymaleic, and lignosulfonic acids, as well as hydrolyzed-polyacrylamide and CMC (carboxymethylcellulose). Among the carboxylic acids, acids with two carboxyl groups are preferred, and acids with three carboxyl groups are more preferred. Of these acids, citric acid is most preferred.
- In general, the amount of acid employed is dictated by the acidity and the molecular weight of that acid. Generally it is found that an acceptable range of acid application is 0.5%-10% by weight of the fibers. As used herein, the “percent by weight,” refers to the weight percent of dry fiber treated with the polyvalent metal containing compound. For citric acid the preferred range of application is 0.5%-3% by weight of the fibers.
- As discussed above, the treatment of fibers with a polyvalent ion-containing compound increases core permeability. Such treatment results in stiffening of the fibers. The stiffened fibers do not swell in water to the extent that untreated fibers do. Consequently existing interfiber channels or other avenues for liquid to flow through an absorbent structure formed from the fibers are kept open to a greater extent by the stiffened fibers than by the untreated fibers. The reduction in wet swell that is produced by polyvalent ion treatment of the fibers, represents an important contribution to the overall improved permeability of an absorbent core containing SAP particles and the treated fibers of the present invention.
- Water retention value (WRV) is an indication of a fiber's ability to retain water under a given amount of pressure. Cellulose fibers that are soaked in water swell moderately, and physically retain water in the swollen fiber walls. When an aqueous fiber slurry is centrifuged, the majority of the water is removed from the fibers. However, a quantity of water is retained by the fiber even after centrifugation, and this quantity of water is expressed as a percentage based on the dry weight of the fiber. All of the fibers treated according to the present invention, have lower WRV values than corresponding untreated fibers. Consequently, all the treated fibers are stiffer than conventional fluff fibers, thus contribute to improved core permeability.
- Reducing Agents
- If desired, reducing agents may be applied to the treated fibers to maintain desired levels of fiber brightness, by reducing brightness reversion. Addition of acidic substances may cause browning of fibers when heated during processing of webs containing the fibers. Reducing agents counter the browning of the fibers. The reducing agent should also bond to the fibers. Preferred agents are sodium hypophosphite and sodium bisulfite, and mixtures thereof.
- Fibers
- A wide variety of fiber types may be treated with the polyvalent metal ion containing compound. However, the use of hydrophilic fibers is preferred. Suitable hydrophilic fibers for use in the present invention include cellulosic fibers, modified crosslinked cellulose fibers, rayon, polyester fibers, hydrophilic nylon, silk wool and the like. Suitable hydrophilic fibers can also be obtained by hydrophilizing hydrophobic fibers. Fibers may be hydrophilized by treatment with surfactants, silica, or surface oxidation, e.g. by ozone in a corona discharge. Such fibers may be derived from, for example, polyolefins such as polyethylene or polypropylene, polyacrylics, polyamides, polystyrenes, polyurethanes and the like.
- For absorbent product applications, the preferred fiber is cellulose. Examples of suitable sources of cellulose fibers include softwood cellulose, hardwood cellulose, cotton, esparto grass, bagasse, hemp, flax, chemically modified cellulose and cellulose acetate. The preferred wood cellulose is bleached cellulose. The final purity of the preferred cellulose fiber of the present invention may range from at least 80% alpha to 98% alpha cellulose, although purity of greater than 95% alpha is preferred, and purity of 96.5% alpha cellulose, is most preferred. As used herein, the term “purity” is measured by the percentage of alpha cellulose present. This is a conventional measurement in the dissolving pulp industry. Methods for the production of cellulose fiber of various purities typically used in the pulp and paper industry are known in the art.
- Curl is defined as a fractional shortening of the fiber due to kinks, twists and/or bends in the fiber. The percent curl of the cellulose fibers of the present invention is preferably from 25% to 80%, and is more preferably 75%. For the purpose of this disclosure, fiber curl may be measured in terms of a two dimensional field. The fiber curl is determined by viewing the fiber in a two dimensional plane, measuring the projected length of the fiber as the longest dimension of a rectangle encompassing the fiber, L (rectangle), and the actual length of the fiber L (actual), and then calculating the fiber curl factor from the following equation:
- Curl Factor=L (actual)/L(rectangle)−1
- A fiber curl index image analysis method is used to make this measurement and is described in U.S. Pat. No. 5,190,563. Fiber curl may be imparted by mercerization. Methods for the mercerization of cellulose typically used in the pulp and paper industry are known in the art.
- The preferred water retention value (WRV) of the cellulose fibers of the present invention is less than85 %, and more preferably between 30% and 80%, and most preferably 40%. The WRV refers to the amount of water calculated on a dry fiber basis, that remains absorbed by a sample of fibers that has been soaked and then centrifuged to remove interfiber water. The amount of water a fiber can absorb is dependent upon its ability to swell on saturation. A lower number indicates internal cross-linking has taken place. U.S. Pat. No. 5,190,563 describes a method for measuring WRV.
- Another source of hydrophilic fibers for use in the present invention, especially for absorbent members providing both fluid acquisition and distribution properties, is chemically stiffened cellulose fibers. As used herein, the term “chemically stiffened cellulose fibers” means cellulose fibers that have been treated to increase the stiffness of the fibers under both dry and wet aqueous conditions. In the most preferred stiffened fibers, chemical processing includes intrafiber crosslinking with crosslinking agents while such fibers are in a relatively dehydrated, defibrated (i.e., individualized), twisted, curled condition. These fibers are reported to have curl values greater than 70% and WRV values less than 60%. Fibers stiffened by crosslink bonds in individualized form are disclosed, for example U.S. Pat. No. 5,217,445 issued Jun. 8, 1993, and U.S. Pat. No. 3,224,926 issued Dec. 21, 1965.
- Saps
- The term “superabsorbent polymer particle” or “SAP” particle is intended to include any particulate form of superabsorbent polymer, including irregular granules, spherical particles (beads), powder, flakes, staple fibers and other elongated particles. “SAP” refers to a normally water-soluble polymer which has been cross-linked to render it substantially water insoluble, but capable of absorbing at least ten, and preferably at least fifteen, times its weight of a physiological saline solution. Numerous examples of superabsorbers and their methods of preparation may be found for example in U.S. Pat. Nos. 4,102,340; 4,467,012; 4,950,264; 5,147,343; 5,328,935; 5,338,766; 5,372,766; 5,849,816; 5,859,077; and U.S. Pat. Re. 32, 649.
- SAPs generally fall into three classes, namely starch graft copolymers, cross-linked carboxymethylcellulose derivatives and modified hydrophilic polyacrylates. Non-limiting examples of such absorbent polymers are hydrolyzed starch-acrylate graft co-polymer, saponified acrylic acid ester-vinyl co-polymer, neutralized cross-linked polyacrylic acid, cross-linked polyacrylate salt, and carboxylated cellulose. The preferred SAPs, upon absorbing fluids, form hydrogels.
- Suitable SAPs yield high gel volumes or high gel strength as measured by the shear modulus of the hydrogel. Such preferred SAPs contain relatively low levels of polymeric materials that can be extracted by contact with synthetic urine (so-called “extractables”). SAPs are well known and are commercially available from several sources. One example is a starch graft polyacrylate hydrogel marketed under the name IM1000™ (Hoechst-Celanese, Portsmouth, Va.). Other commercially available superabsorbers are marketed under the trademark SANWET™ (Sanyo Kasei Kogyo Kabushiki, Japan), SUMIKA GEL™ (Sumitomo Kagaku Kabushiki Haishi, Japan), FAVOR™ (Stockhausen, Garyville, La.) and the ASAP™ series (Chemdal, Aberdeen, Miss).
- Suitable SAP particles for use in the present invention include those discussed above, and others, provided that the SAP particle provides improved permeability of an absorbent core made with the SAP and a hydrophilic fiber treated according to the present invention. Most preferred for use with the present invention are polyacrylate-based SAPs.
- As used in the present invention, SAP particles of any size or shape suitable for use in an absorbent core may be employed.
- Absorbent Core Structures
- The treated fibers of the present invention may be used in combination with SAP particles, to form a stratum of an absorbent core, useful in forming an absorbent structure for use in manufacturing an absorbent article. The treated fibers begin to show improved core permeability in a mixture of 20% SAP and 80% fiber in an absorbent core, even better permeability is displayed in a mixture of 40% SAP and 60% fiber in an absorbent core, and further improvement in permeability is observed in a mixture of 60% to 80% SAP and 40% to 20% fiber in an absorbent core. Preferably, the treated fibers will be used to form one stratum of a multi-strata absorbent structure. Absorbent structures particularly useful in infant diapers and adult incontinence products often include at least two defined strata—an upper acquisition stratum and a lower storage stratum. Sometimes, a distribution stratum is provided between the acquisition and storage strata. Optionally, a wicking stratum is provided below the storage stratum.
- Typically SAP particles are provided in the storage stratum, although such SAP particles may also, or alternatively be provided in a distribution stratum. The treated fibers or other treated substrates of the present invention may be located in any stratum, provided that upon exposure of the absorbent structure to a liquid insult, the liquid contacts the treated fiber, and then carries the polyvalent metal ion to the SAP particles. Preferably, in a multi-strata absorbent structure, the treated fiber of the present invention will be provided in the storage layer.
- Absorbent Articles
- The treated fibers of the present invention may be employed in any disposable absorbent article intended to absorb and contain body exudates, and which are generally placed or retained in proximity with the body of the wearer. Disposable absorbent articles include infant diapers, adult incontinence products, training pants, sanitary napkins and other feminine hygiene products.
- A conventional disposable infant diaper generally includes a front waistband area, a rear waistband area and a crotch region there between. The structure of the diaper generally includes a liquid pervious topsheet, a liquid impervious backsheet, an absorbent structure, elastic members, and securing tabs. Representative disposable diaper designs may be found, for example in U.S. Pat. No. 4,935,022 and U.S. Pat. No. 5,149,335. U.S. Pat. No. 5,961,505 includes representative designs for feminine hygiene pads.
- The absorbent structure incorporating the treated fibers of the present invention may be formed in place by blending individualized fibers and SAP particles and applying them to a form under applied vacuum to create an absorbent structure of desired shape. Alternatively, the absorbent structure may be formed separately as a continuous roll good, preferably using airlaid (or “dryformed”) technology.
- Fiber Treatment
- The fibers suitable for use in absorbent structures may be treated in a variety of ways to provide the polyvalent metal ion-containing compound in close association with the fibers. A preferred method is to introduce the compound in solution with the fibers in slurry form and cause the compound to precipitate onto the surface of the fibers. Alternatively, the fibers may be sprayed with the compound in aqueous or non-aqueous solution or suspension. The fibers may be treated while in an individualized state, or in the form of a web. For example, the compound may be applied directly onto the fibers in powder or other physical form. Whatever method is used, however, it is preferred that the compound remain bound to the fibers, such that the compound is not dislodged during normal physical handling of the fiber in forming the absorbent structure and absorbent articles or use of the article, before contact of the fiber with liquid. Upon contact of the treated fibers with liquid, the applied compound should be released from the fiber to provide ions within the liquid.
- Preferred Method of Treating Fibers
- In a preferred embodiment, the treated fibers of the present invention are made from cellulose fiber, obtained from Buckeye Technologies Inc. (Memphis, Tennessee). The pulp is slurried, the pH is adjusted to about 4.0, and aluminum sulfate (Al2(SO4)3) in aqueous solution is added to the slurry. The slurry is stirred and the consistency reduced. Under agitation, the pH of the slurry is increased to approximately 5.7. The fibers are then formed into a web or sheet, dried, and sprayed with a solution of citric acid at a loading of 2.5 weight % of the fibers. The web is then packaged and shipped to end users for further processing, including fiberization to form individualized fibers useful in the manufacture of absorbent products. If a reducing agent is to be applied, preferably it is applied before a drying step and following any other application steps. The reducing agent may be applied by spraying, painting or foaming.
- Without intending to be bound by theory, it is believed that by this process, the soluble Al2(SO4)3 introduced to the pulp slurry is converted to insoluble Al(OH)3 as the pH is increased. The insoluble aluminum hydroxide precipitates onto the fiber. Thus, the resultant fibers are coated with Al(OH)3 or contain the insoluble metal within the fiber interior. The citric acid sprayed on the web containing the fibers dries on the fibers. When the Al(OH)3 treated fibers are formed into an absorbent product, the citric acid creates a locally acidic environment when the citric acid-treated fibers of the absorbent product are exposed to a liquid insult (e.g., urine). The decreased pH created by the acid environment converts the Al(OH)3 to the soluble form of aluminum including a citric acid complex of this metal. In this way, aluminum ions may become available in solution to locally and temporarily inhibit the swelling of superabsorbent polymers (also present in the absorbent material) thereby minimizing or preventing gel-blocking.
- In another preferred embodiment, the above procedure is followed to treat the fibers with precipitated Al(OH)3, and in a subsequent step, aluminum sulfate is applied, preferably by spraying, onto the Al(OH)3-treated fibers. Preferably the aluminum sulfate is applied to the web, before the web is introduced to web dryers. Application to the wet web provides better distribution of the aluminum sulfate through the web. The acidic environment provided by the aluminum sulfate is also conducive to release of soluble aluminum ions from the Al(OH)3 precipitate.
- A hierarchy of preferred embodiments is exemplified as follows: a two component mixture of (1) cellulosic fibers pretreated with a water soluble aluminum compound and (2) SAP particles in an absorbent core (Example 4), provides a higher level of core permeability than a comparable three component mixture of (1) cellulosic fibers and (2) a water soluble aluminum compound and (3) SAP particles in an absorbent core (Example 12), and a higher level of core permeability than a two component mixture of (1) SAP particles pretreated with a water soluble aluminum compound in an aqueous solution and (2) cellulosic fibers in an absorbent core (Example 15). These results are exemplified in the procedures set forth below.
- Treatment of SAP Particles
- Improved core permeability may be obtained by coating the surface of SAP particles with a polyvalent ion salt, and combining the coated SAP particle with a fiber in an absorbent structure. The particles are coated in contrast to reacting or complexing the SAP particles with a polyvalent cation salt. Coating of the SAP particle with the salt is accomplished by mixing the SAP particles with a non-aqueous solution of the polyvalent ion salt, and subsequently removing the non-aqueous solvent, leaving a coating of the salt on the surface of the SAP particle. For example, an anhydrous methanol solution of aluminum sulfate may be mixed with SAP particles at room temperature, for example Favor™ SXM 9100, the mixture dried, and the granular coated SAP particles mixed with fluff fiber in an absorbent core. The core permeability for such a structure is much higher than that obtained when an equivalent amount of polyvalent ion salt in aqueous solution is used to treat SAP particles, indicating superior core permeability with aluminum sulfate-coated particles compared to aluminum cation-complexed SAP particles. Although methanol is the preferred non-aqueous solvent, any solvent which dissolves the salt but does not swell the SAP particle, may be used. Examples include alcohols, such as ethanol, n-propanol, iso-propanol and acetone.
- The following procedures are employed in the Examples set forth at the end of the specification.
- Formation of Air Laid Structures
- A Kamas mill (Kamas Industri AB, Sweden) is used to disintegrate pulp sheets into fluff pulp. A pad former (Buckeye Technologies, Memphis, Tenn.) is used to combine the fluff and SAP particles.
- Laboratory air-laid absorbent structures are made by combining fiber and SAP particles in the laboratory to simulate the process of an absorbent core construction on a full-scale commercial line. Fiber and SAP particles are loaded into the pad former. Fiber and SAP particles are combined through air vortices and become one single structure via the applied vacuum. The air-laid structure is then die-cut to dimensions specific for performance testing. For testing purposes, the airlaid structure should have dimensions of 14″×14″ at a target basis weight (0.30 g/in2 or 0.22 g/in2).
- Measurement of Ion Content
- Metal ion content, including aluminum or iron content, in pulp samples is determined by wet ashing (oxidizing) the sample with nitric and perchloric acids in a digestion apparatus. A blank is oxidized and carried through the same steps as the sample. The sample is then analyzed using an inductively coupled plasma spectrophotometer (“ICP”) (e.g., a Perkin-Elmer ICP 6500). From the analysis, the ion content in the sample can be determined in parts per million. The polyvalent cation content should be between 0.25% and 5.0% by weight of fibers, preferably between 0.25% and 2.5% by weight of fibers, and more preferably between 0.4% and 1.2% by weight of fibers.
- Measurement of Ion Extraction
- The percentage of ions extracted from fibers in a saline solution is measured by submerging the test fibers in a saline solution that is shaken for 24 hours. During this period, ions are extracted from the fibers and into the solution. The ion concentration in the solution is measured using an ICP and compared with the ion content in the original fiber sample to determine the percentage of ion removed due to prolonged exposure to saline under agitation. The ion extraction should exceed 5%, preferably exceed 25%, more preferably exceed 50%, and most preferably exceed 90%.
- Measurement of Vertical Permeability
- Vertical Permeability is determined using the following procedure. This procedure was adapted from the method disclosed in U.S. Pat. No. 5,562,642.
- A Kamas Cell Mill (Kamas Industri AB, Sweden) apparatus is used to form disintegrated pulp sheets that in turn are used to produce fluff. A pad former (Buckeye Technologies Inc., Memphis, Tenn.) is used to combine SAP particles and fiber to prepare 14″×14″ test pads. Test pads are constructed at a basis weight of 0.3 g/in2 and pressed to a density of 0.15 g/cc. Samples are die-cut to 2¼″ diameter circles and conditioned before testing. The circles are dried in a forced air oven, then placed in a dessicator until the permeability test is run. The sample is then positioned into a vertical cylinder that contains a base (sample platform) constructed from wire mesh. See FIG. 3 for an illustration of the vertical permeability test apparatus. The vertical cylinder has an inside diameter of 2¼″. A weight placed onto the sample supplies about 0.3 lb/in2 of pressure perpendicular to the sample. The sample is saturated in fluid (0.9% saline) for one hour. After one hour, the vertical cylinder containing the sample is secured over (but not in contact with) a weighing balance. The sample is initially insulted with 50 ml of 0.9% saline via a ⅜″ hole centered in the weight. A 25-ml insult is added for every 25 grams of fluid that transferred to the balance until the balance reads 100 grams. Fluid transferred by the sample is measured per unit of time to quantify the permeability for a given sample. Absorption capacity for the samples is also recorded.
- Measurement of Inclined Permeability
- The following procedure is used to measure inclined permeability. This procedure was adapted from the procedure disclosed in U.S. Pat. No. 5,147,343. A Kamas Cell Mill (Kamas Industri AB, Sweden) apparatus is used to form disintegrated pulp sheets that in turn are used to produce fluff. A pad former was used to combine SAP particles and fibers to prepare 14″×14″ test pads. Test pads are constructed at a basis weight of 0.22 g/in2 and pressed to a density of 0.15 g/cc. Permeability samples are die-cut to eleven square inches and conditioned before testing. Refer to FIG. 1 for an illustration of the inclined permeability test apparatus used in the procedure. Permeability samples are placed on a Teflon coated block inclined at a 45-degree angle. Attached to this block is a fluid head box connected by ¼″ tubing to a vertically adjustable fluid reservoir. The front edge of the sample pad is centered onto and secured to the head box. The head box is designed with three {fraction (3/16)}″ diameter holes that are spaced {fraction (9/16)}″ apart. A top block coated with Teflon, with a congruent 45-degree angle, is placed on top of the sample pad. Lubricated pegs are inserted into the bottom block (sample platform) at a 60-degree angle to prevent the top block from slipping while allowing for uniform sample expansion after saturation. A 724.4 g weight, along with the weight of the top block supplies about 0.3 lbs/in2 of pressure perpendicular to the sample. The fluid (0.9% saline) level is adjusted to produce and maintain an inverted meniscus. Once saturation occurs, the sample pad acts as a siphon by transferring fluid to a tared receiving container atop a balance located below the end of the sample. Liquid transferred by the sample is measured per unit time to establish a flow rate. Permeability for a given sample is quantified after the flow rate reaches equilibrium. For example, FIG. 2 shows the incline permeability at various time intervals for 50% SAP and 50% cellulose fiber mixtures, and 70% SAP and 30% cellulose fiber mixtures. The figure also shows the increased permeability produced by the invention fiber in a mixture with SAP (Example 3).
- Calculation of Permeability Factor
- The permeability factor is determined by summing the permeability in gm/min from the vertical permeability and the inclined permeability. The sum is taken as follows:
- Perm Factor=(vertical2+inclined2)1/2
- where “vertical” permeability and “inclined” permeability are express as gm/min. The factor is reported as a dimensionless number although the actual dimensions are gm/min.
- Measurement of Horizontal Wicking (Core Utilization)
- Horizontal wicking samples of about 4″×14″ are placed onto a level platform with bordering grooves to capture “runoff” fluid (0.9% saline). Both laboratory test cores or manufactured diaper cores may be used. For laboratory cores, an acquisition-distribution layer (ADL) from a commercial diaper cut to 3″×7″ is placed on top of the sample where fluid is introduced. Then a second board is placed on top of the sample and ADL. The top board contained an insult reservoir with a {fraction (11/2)}″ inside diameter. The insult region, relative to the sample, was 5″ centered from the front end or end closest to the insult reservoir. Two 10 lb. weights placed on the top board along with the weight of the top board supplied about 0.40 lbs/in2 of pressure perpendicular to the sample. Three 100 ml insults were introduced to the sample in twenty-minute intervals. After one hour, the sample was sectioned and weighed to determine the distance that liquid was transported away form the insult region. Horizontal wicking was quantified by the sum of the last three inches, on a gram of fluid per gram of core sample basis.
- The following examples are intended to illustrate the invention without limiting its scope.
- A slurry of bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies consisting of 4.5 parts fiber/100 parts slurry was diluted with sufficient water to provide 0.9 parts fiber/100 parts slurry and adjusted to a pH of 5.5. The resultant slurry was continuously dewatered on a sheeting machine where a sheet was formed at rush/drag ratio of 1.0, couched, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry. The sheet was dried using conventional drum dryers to 93.5 percent solids. The sheet was reeled on a continuous roll.
- Sheets from the roll were defiberized in a Kamas mill. An ion extraction test was performed on the fibers as described above. The ionic extraction of the fiber was measured at 0%. Vertical and inclined permeability tests were performed as described above using test cores that were a mixture of 70% by weight of SAP particles and 30% by weight of fibers. The permeability factor was then calculated. When
FAVOR™ SXM 70 SAP (obtained from Stockhausen, Inc.) was used, a permeability factor of 16 was obtained. - Comparative Example 1 was repeated, except that SAP FAVOR™ SXM 9100 was used instead of
FAVOR™ SXM 70. The permeability factor obtained was 141. - Cellulose fibers were treated as follows. A total of 9.36 parts hydrated aluminum sulfate (Al2(SO4)3*14 H2O) from General Chemical Corporation, per 100 parts bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies were added to a slurry consisting 4.5 parts fiber/100 parts slurry. The slurry had a pH of 3.2. After 25 minutes of mixing 3.0 parts sodium hydroxide/100 parts fiber were added along with sufficient water to provide 0.9 parts fiber/100 parts slurry at a pH of 5.7. The temperature was adjusted to 60° C. The resultant slurry was continuously dewatered on a sheeting machine where the sheet was formed at 1.0 rush/drag ratio, couched, then pressed and densified using three stages of pressing to 48 parts fiber/100 parts total. The sheet was dried using conventional drum dryers to 93.5 percent solids. While continuously reeling, a spray of 50% citric acid solution was applied to one surface of the sheet at a loading of 2.5 parts per 100 parts of fiber. The reeled sheet was then sized into individual rolls.
- The sheet was defiberized in a Kamas mill, and the ionic extraction test described above was performed. The fiber was found to have an ionic extraction of 34% and an aluminum content of approximately 7,500 ppm. Vertical and inclined permeability tests were performed on test cores using a mixture of 70% by weight of SAP particles and 30% by weight of fibers. The permeability factor using
FAVOR™ SXM 70 SAP was 31. - Example 1 was repeated except that the SAP used was FAVOR™ SXM 9100. The permeability factor obtained was 177.
- A slurry of bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies consisting of 4.5 parts fiber/100 parts slurry was diluted with sufficient water to provide 0.9 parts fiber/100 parts slurry and adjusted to a pH of 5.5. The resultant slurry was continuously dewatered on a sheeting machine and a sheet was formed at a rush/drag ratio of 1.0, couched, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry. The sheet was dried using conventional drum dryers to 93.5 percent solids. The sheet was then reeled. During reeling, 6.1 parts of hydrated aluminum sulfate (Al2(SO4)3*14 H2O, 50% aqueous solution) is applied by spraying per 100 parts fiber. The fiber was reeled on a continuous roll. The resultant reel was sized into individual rolls. The sheets were defiberized in a Kamas mill and the ionic extraction measured, and determined to be 86%. The aluminum content of the fibers was 5,500 ppm. Permeability tests were conducted as described above using test cores that were a mixture of 70% by weight SAP and 30% by weight fibers. The permeability factor using
FAVOR™ SXM 70 SAP was 44. - Example 3 was repeated except that the aluminum content of the fibers was 5445 ppm, and the SAP used was FAVOR™ SXM 9100. The permeability factor obtained was 212. The ion extraction was 86%.
- 12.1 g of ferric nitrate (Fe(NO3)3) (Fisher Chemical Co.) per 152 g bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies were added to a slurry of 4.5 parts fiber/100 parts slurry. The slurry had a pH of 2.76. After mixing and dilution to 0.9 parts fiber/100 parts slurry, 27.1 ml of 10% sodium hydroxide were added to provide a pH of 5.7. The resultant slurry was dewatered on a dynamic handsheet former (Formette Dynamique Brevet, Centre Technique de L'Industrie, Ateliers de Construction Allimand, Appareil No. 48) and was pressed to 48 parts fiber/100 parts total. The sheet was dried to 93.5 percent solids. After drying, 2.5 parts of 50% citric acid solution per 100 parts of fiber were applied to the sheet.
- The sample sheet was defiberized in a Kamas mill as described above. Permeability was determined on test cores formed as described above, that were a mixture of FAVOR™ SXM 9100, at 70% by weight and
fiber 30% by weight. The permeability factor was calculated to be 178. - 9.36 parts hydrated aluminum sulfate (Al2(SO4)3*14 H2O) per 100 parts bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies were added to a slurry consisting of 4.5 parts fiber/100 parts slurry. After addition of the aluminum sulfate, the slurry had a pH of 3.2. After 25 minutes of mixing, 3.0 parts sodium hydroxide/100 parts fiber were added along with sufficient water to provide 0.9 parts fiber/100 parts slurry at a pH of 5.7 and temperature of 60° C. The resultant slurry was continuously dewatered on a sheeting machine and a sheet formed at a 1.0 rush/drag ratio, couched, then pressed and densified using three stages of pressing to 48 parts fiber/100 parts total. The sheet was dried to 93.5 percent solids. To this sheet sample was applied three
parts - The sheet was defiberized in a Kamas mill and the fiber was determined to have an ionic extraction of 12.4%. All permeability factor testing was performed using pads made with 70% by weight of
FAVOR™ SXM 70 SAP and 30% weight of fiber. The permeability factor was determined to be 38. - 9.36 parts hydrated aluminum sulfate (Al2(SO4)3*14 H2O) per 100 parts bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies were added to a slurry consisting of 4.5 parts fiber/100 parts slurry. After addition of the aluminum sulfate, the slurry had a pH of 3.2. After 25 minutes of mixing, 3.0 parts sodium hydroxide/100 parts fiber were added along with sufficient water to provide 0.9 parts fiber/100 parts slurry at a pH of 5.7 and temperature of 60° C. The resultant slurry was continuously dewatered on a sheeting machine and a sheet formed at a 1.0 rush/drag ratio, couched, then pressed and densified using three stages of pressing to 48 parts fiber/100 parts total. The sheet was dried to 93.5 percent solids. To this sheet sample was applied one part para-toluenesulfonic acid (PTSA) from Aldrich Chemical Company by spraying per 100 parts of fiber.
- The sheet was defiberized in a Kamas mill and the fiber was determined to have an ionic extraction of 13.4%. All permeability factor testing was performed using test cores made with 70% by weight of
FAVOR™ SXM 70 SAP and 30% by weight of fiber. The permeability factor was determined to be 32. - High porosity commercial fiber (HPZ) was obtained from Buckeye Technologies Inc. in sheet form. The fibers had a WRV of 78.7, a curl of 51% and a 96.5% alpha cellulose content. A total of 7.7 parts of hydrated aluminum sulfate octadecahydrate (Aldrich Chemical Company) per 100 parts fiber were applied to the sheeted material by spraying.
- Ion extraction was measured for the fiber as 100%. Permeability was measured after preparing a test pad that was 30% by weight of fibers and 70% by weight of FAVOR™ SXM 9100 SAP. The permeability factor was 241.
- High purity commercial cotton fiber (GR702) was obtained from Buckeye Technologies Inc. in sheet form. A total of 7.7 parts of aluminum sulfate octadecahydrate per 100 parts fiber were applied to the sheeted material by spraying. Ion extraction was measured for the fiber as 99.0%. Permeability was measured after preparing a pad that was 30% by weight of fibers and 70% by weight of FAVOR™ SXM 9100 SAP. The permeability factor was 219.
- Fibers were prepared as disclosed in U.S. Pat. No. 5,190,563 by applying 4.7% citric acid and 1.6% sodium hypophosphite to a Southern Softwood Kraft pulp sheet. After individualizing and curing at 340° F. for 7.5 minutes, the pulp had a WRV of 44 and a curl of about 75%. The individualized fibers were treated by spraying 3.42 parts of hydrated aluminum sulfate (Al2(SO4)3*14 H2O) per 100 parts fiber were added to the fibers and the fibers allowed to dry. The ionic extraction for the fibers was measured at 49.8%. The aluminum content of the fibers was measured at 10,869 ppm. Test pads were made with 30% by weight of the treated fibers and 70% by weight FAVOR™ SXM 9100 SAP and the permeability factor measured. The factor was found to be 231.
- A sheet of synthetic hydrophilic non-woven material from BBA corporation, product number H018B7W, was selected and treated with 1.03 grams of aluminum sulfate octadecahydrate per square foot of material by spraying and allowed to dry. Test pads were made from 30% by weight bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies and 70% by weight FAVOR™ SXM 9100 SAP, with the treated non-woven material as a topsheet, and the permeability factor measured. The permeability factor was 191.
- An absorbent core of improved permeability was prepared by adding 2.4 parts of aluminum sulfate octadecahydrate (51.3% aluminum sulfate) in powder form to 100 parts of a 30% by weight fiber and 70% by weight SAP core as described in the method for producing cores. The permeability factor with FAVOR™ SXM 9100 at 70% SAP was 207.
- A slurry of bleached southern softwood Kraft (BSSK) fibers Buckeye Technologies consisting of 4.5 parts fiber/100 parts slurry was diluted with sufficient water to provide 0.9 parts fiber/100 parts slurry and adjusted to a pH of 5.5. The resultant slurry was continuously dewatered on a sheeting machine where the sheet was formed at a rush/drag ratio of 1.0, couched, then treated by spraying with 12.35 parts of hydrated aluminum sulfate and 3.17 parts of sodium hypophosphite per one hundred parts of fiber, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry. The sheet was dried using conventional drum dryers to 93.5 percent solids. The fiber was reeled on a continuous roll. The resultant reel was sized into individual rolls.
- The sheets were defiberized in a Kamas mill and the ionic extraction of the fiber was measured at 95%. The permeability factor was determined to be 216, using at test core that was 30% by weight fiber and 70% by weight FAVOR™ SXM 9100.
- A total of 9.36 parts of hydrated aluminum sulfate (Al2(SO4)3*14 H2O) per 100 parts of bleached southern softwood Kraft (BSSK) fibers from Buckeye Technologies were added to a slurry consisting of 4.5 parts fiber/100 parts slurry. The slurry had a pH of 3.2. After 25 minutes of mixing, 3.0 parts of sodium hydroxide per 100 parts of fiber were added with sufficient water to provide 0.9 parts fiber per 100 parts slurry at a pH of 5.7 and at a temperature of 60° C. The resultant slurry was continuously dewatered on a sheeting machine where the sheet was formed at a rush/drag ratio of 1.0, couched, then treated by spraying with 12.35 parts of hydrated aluminum sulfate and 3.17 parts of sodium hypophosphite per one hundred parts of fiber, then pressed and densified through three stages of pressing to 48 parts fiber/100 parts slurry. The sheet was dried using conventional drum dryers to 93.5 percent solids. The fiber was reeled on a continuous roll. The resultant reel was sized into individual rolls.
- The sheets were defiberized in a Kamas mill and the ionic extraction of the fiber was measured at 38.2% and the aluminum content was 9475 ppm. The permeability factor was determined to be 213, using a test core that was 30% by weight fiber and 70% by weight FAVOR™ SXM 9100.
- An absorbent core was prepared by combining three parts of defiberized fluff fiber by weight with seven parts by weight of pretreated FAVOR™ SXM 9100 SAP. The FAVOR™ SXM 9100 SAP had been pretreated with aqueous aluminum sulfate octadecahydrate at ratio of 3.7 parts of dry aluminum sulfate octadecahydrate to 100 parts of SAP, dried at 125° C. for 3 hours, crushed and sieved to the same particle size as the untreated SAP. The permeability factor for this core was determined to be 187.
- An absorbent core was prepared by combining three parts of defiberized fluff fiber by weight with seven parts by weight of pretreated FAVOR™ SXM 9100 SAP. The FAVOR™ SXM 9100 SAP had been pretreated with a methanol solution of aluminum sulfate octadecahydrate at a ratio of 3.7 parts of dry aluminum sulfate octadecahydrate to 100 parts of SAP, air dried in an exhaust hood to remove visible liquid, and oven dried at 40° C. for two hours. The permeability factor for this core was determined to be 268.
Claims (106)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/866,210 US20040224588A1 (en) | 1998-12-24 | 2004-06-10 | Absorbent structures of chemically treated cellulose fibers |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11384998P | 1998-12-24 | 1998-12-24 | |
US11756599P | 1999-01-27 | 1999-01-27 | |
US09/469,930 US6562743B1 (en) | 1998-12-24 | 1999-12-21 | Absorbent structures of chemically treated cellulose fibers |
US10/360,147 US6770576B2 (en) | 1998-12-24 | 2003-02-07 | Absorbent structures of chemically treated cellulose fibers |
US10/866,210 US20040224588A1 (en) | 1998-12-24 | 2004-06-10 | Absorbent structures of chemically treated cellulose fibers |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/360,147 Continuation US6770576B2 (en) | 1998-12-24 | 2003-02-07 | Absorbent structures of chemically treated cellulose fibers |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040224588A1 true US20040224588A1 (en) | 2004-11-11 |
Family
ID=26811548
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/469,930 Expired - Lifetime US6562743B1 (en) | 1998-12-24 | 1999-12-21 | Absorbent structures of chemically treated cellulose fibers |
US10/360,147 Expired - Lifetime US6770576B2 (en) | 1998-12-24 | 2003-02-07 | Absorbent structures of chemically treated cellulose fibers |
US10/866,210 Abandoned US20040224588A1 (en) | 1998-12-24 | 2004-06-10 | Absorbent structures of chemically treated cellulose fibers |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/469,930 Expired - Lifetime US6562743B1 (en) | 1998-12-24 | 1999-12-21 | Absorbent structures of chemically treated cellulose fibers |
US10/360,147 Expired - Lifetime US6770576B2 (en) | 1998-12-24 | 2003-02-07 | Absorbent structures of chemically treated cellulose fibers |
Country Status (14)
Country | Link |
---|---|
US (3) | US6562743B1 (en) |
EP (2) | EP1139961B1 (en) |
JP (1) | JP2003523484A (en) |
KR (1) | KR20010089673A (en) |
CN (1) | CN1281202C (en) |
AR (3) | AR029448A1 (en) |
AT (1) | ATE551978T1 (en) |
AU (1) | AU759840B2 (en) |
BR (1) | BR9917115B1 (en) |
CA (1) | CA2356651C (en) |
ES (1) | ES2388031T3 (en) |
PE (1) | PE20001307A1 (en) |
TW (1) | TWI232744B (en) |
WO (1) | WO2000038607A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008135011A2 (en) * | 2007-05-03 | 2008-11-13 | 3Mach Gmbh | Covering and sleeve |
US8946100B2 (en) | 2003-12-19 | 2015-02-03 | Buckeye Technologies Inc. | Fibers of variable wettability and materials containing the fibers |
US20170183817A1 (en) * | 2015-12-29 | 2017-06-29 | Weyerhaeuser Nr Company | Modified fiber from shredded pulp sheets, methods, and systems |
WO2021168049A1 (en) * | 2020-02-20 | 2021-08-26 | Georgia Tech Research Corporation | Treated cellulosic materials and methods of making the same |
Families Citing this family (106)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10007566C2 (en) * | 2000-02-18 | 2003-02-20 | Hakle Kimberly De Gmbh | Absorbent article |
MXPA02007962A (en) * | 2000-02-18 | 2005-07-01 | Hakle Kimberly De Gmbh | Absorbent articles. |
US6627041B2 (en) * | 2000-03-06 | 2003-09-30 | Georgia-Pacific Corporation | Method of bleaching and providing papermaking fibers with durable curl |
KR100853920B1 (en) | 2000-03-14 | 2008-08-25 | 제임스 하디 인터내셔널 파이낸스 비.브이. | Fiber cement building materials with low density additives |
CN1246246C (en) * | 2000-10-04 | 2006-03-22 | 詹姆斯哈迪国际财金公司 | Fiber cement composition materials using cellulose fibers loaded with inorganic and/or organic substances |
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 |
JP5226925B2 (en) * | 2000-10-17 | 2013-07-03 | ジェイムズ ハーディー テクノロジー リミテッド | Fiber cement composite using durable cellulose fibers treated with biocides |
CZ20032693A3 (en) * | 2001-03-09 | 2004-07-14 | James Hardie Research Pty. Limited | Fiber reinforced cement composite materials employing chemically treated fibers exhibiting enhanced dispersing property |
EP1399726A1 (en) * | 2001-06-13 | 2004-03-24 | MERCK PATENT GmbH | Restricted access materials for spme |
KR100870629B1 (en) * | 2001-06-29 | 2008-11-26 | 에보닉 스톡하우젠 게엠베하 | Superabsorbent carboxyl-containing polymers with odor control properties |
EP1448375B2 (en) | 2001-11-09 | 2012-08-01 | Buckeye Technologies Inc. | Unitary absorbent multilayered core |
US20030119394A1 (en) * | 2001-12-21 | 2003-06-26 | Sridhar Ranganathan | Nonwoven web with coated superabsorbent |
US6942726B2 (en) | 2002-08-23 | 2005-09-13 | Bki Holding Corporation | Cementitious material reinforced with chemically treated cellulose fiber |
AU2003257150B2 (en) | 2002-08-23 | 2009-07-30 | Gp Cellulose Gmbh | Cementitious material reinforced with chemically treated cellulose fiber |
AU2003901529A0 (en) * | 2003-03-31 | 2003-05-01 | James Hardie International Finance B.V. | A durable high performance fibre cement product and method of making the same |
MXPA05003691A (en) | 2002-10-07 | 2005-11-17 | James Hardie Int Finance Bv | Durable medium-density fibre cement composite. |
US6837496B2 (en) * | 2002-12-02 | 2005-01-04 | The United States Of America As Represented By The Secretary Of The Army | Bullet trapping medium and system |
NZ541250A (en) | 2003-01-09 | 2008-09-26 | James Hardie Int Finance Bv | Fibre cement composite materials using bleached cellulose fibres |
RU2333229C2 (en) * | 2003-06-24 | 2008-09-10 | Ниппон Шокубаи Ко., Лтд. | Water-absorbing resin-based composition, methods for obtaining same (versions), absorber and absorbing device based thereon |
ATE489345T1 (en) * | 2003-08-29 | 2010-12-15 | Bki Holding Corp | METHOD FOR INSERTING FIBERS INTO CONCRETE |
EP1518566B1 (en) * | 2003-09-25 | 2008-04-09 | The Procter & Gamble Company | Absorbent articles comprising superabsorbent polymer particles having a non-covalently bonded surface coating |
EP1518567B1 (en) * | 2003-09-25 | 2017-06-28 | The Procter & Gamble Company | Absorbent articles comprising fluid acquisition zones with coated superabsorbent particles |
US7579402B2 (en) * | 2003-11-12 | 2009-08-25 | Evonik Stockhausen, Inc. | Superabsorbent polymer having delayed free water absorption |
US20050142965A1 (en) * | 2003-12-29 | 2005-06-30 | Kimberly-Clark Worldwide, Inc. | Surface charge manipulation for improved fluid intake rates of absorbent composites |
US8575045B1 (en) | 2004-06-10 | 2013-11-05 | The United States Of America As Represented By The Secretary Of The Army | Fiber modified with particulate through a coupling agent |
US7998571B2 (en) | 2004-07-09 | 2011-08-16 | James Hardie Technology Limited | Composite cement article incorporating a powder coating and methods of making same |
US20060029567A1 (en) | 2004-08-04 | 2006-02-09 | Bki Holding Corporation | Material for odor control |
US7465684B2 (en) * | 2005-01-06 | 2008-12-16 | Buckeye Technologies Inc. | High strength and high elongation wipe |
US7892648B2 (en) * | 2005-01-21 | 2011-02-22 | International Business Machines Corporation | SiCOH dielectric material with improved toughness and improved Si-C bonding |
US20060173431A1 (en) * | 2005-02-01 | 2006-08-03 | Laumer Jason M | Absorbent articles comprising polyamine-coated superabsorbent polymers |
US20060173433A1 (en) * | 2005-02-01 | 2006-08-03 | Laumer Jason M | Absorbent articles comprising polyamine-coated superabsorbent polymers |
US20060173432A1 (en) * | 2005-02-01 | 2006-08-03 | Laumer Jason M | Absorbent articles comprising polyamine-coated superabsorbent polymers |
EP2628837B1 (en) | 2005-04-01 | 2017-01-04 | Buckeye Technologies Inc. | Nonwoven material for acoustic insulation, and process for manufacture |
TWI344469B (en) | 2005-04-07 | 2011-07-01 | Nippon Catalytic Chem Ind | Polyacrylic acid (salt) water-absorbent resin, production process thereof, and acrylic acid used in polymerization for production of water-absorbent resin |
US7423079B2 (en) * | 2005-05-17 | 2008-09-09 | Luna Innovations Incorporated | Flame-retardant synthetic textile articles and methods of making the same |
CN104109983A (en) | 2005-05-24 | 2014-10-22 | 国际纸业公司 | Modified kraft fibers |
CN101257875A (en) | 2005-09-06 | 2008-09-03 | 泰科保健集团有限合伙公司 | Self contained wound dressing with micropump |
TWI394789B (en) | 2005-12-22 | 2013-05-01 | Nippon Catalytic Chem Ind | Water-absorbent resin composition, method of manufacturing the same, and absorbent article |
EP1837348B9 (en) | 2006-03-24 | 2020-01-08 | Nippon Shokubai Co.,Ltd. | Water-absorbing resin and method for manufacturing the same |
CA2648966C (en) | 2006-04-12 | 2015-01-06 | James Hardie International Finance B.V. | A surface sealed reinforced building element |
US7785710B2 (en) | 2006-10-02 | 2010-08-31 | Weyerhaeuser Nr Company | Superabsorbent particles containing carboxyalkyl cellulose and temporary metal crosslinks |
US20080079188A1 (en) * | 2006-10-02 | 2008-04-03 | Weyerhaeuser Co. | Methods for the preparation of mixed polymer superabsorbent fibers |
US7645806B2 (en) * | 2006-10-02 | 2010-01-12 | Weyerhaeuser Nr Company | Methods for the preparation of superabsorbent particles containing carboxyalkyl cellulose |
US20080081165A1 (en) * | 2006-10-02 | 2008-04-03 | Weyerhaeuser Co. | Fibrous superabsorbent composite containing cellulose |
US20080082065A1 (en) * | 2006-10-02 | 2008-04-03 | Weyerhaeuser Co. | Mixed polymer superabsorbent fibers containing cellulose |
US7717995B2 (en) * | 2006-10-02 | 2010-05-18 | Weyerhaeuser Nr Company | Methods for the preparation of mixed polymer superabsorbent fibers containing cellulose |
US20080078514A1 (en) * | 2006-10-02 | 2008-04-03 | Weyerhaeuser Co. | Methods for the preparation of cellulose fibers having superabsorbent particles adhered thereto |
US20080082067A1 (en) * | 2006-10-02 | 2008-04-03 | Weyerhaeuser Co. | Cellulose fibers having superabsorbent particles adhered thereto |
US7625463B2 (en) | 2006-10-02 | 2009-12-01 | Weyerhaeuser Nr Company | Methods for the preparation of fibrous superabsorbent composite containing cellulose |
US8021518B2 (en) * | 2006-11-30 | 2011-09-20 | Nalco Company | Method of applying a super-absorbent composition to tissue or towel substrates |
US7935860B2 (en) * | 2007-03-23 | 2011-05-03 | Kimberly-Clark Worldwide, Inc. | Absorbent articles comprising high permeability superabsorbent polymer compositions |
US8236884B2 (en) * | 2007-03-23 | 2012-08-07 | Evonik Stockhausen, Llc | High permeability superabsorbent polymer compositions |
US7591891B2 (en) * | 2007-06-25 | 2009-09-22 | Weyerhaeuser Nr Company | Fibrous blend and methods of preparation |
US7749317B2 (en) | 2007-06-25 | 2010-07-06 | Weyerhaeuser Nr Company | Fibrous blend and method of making |
US8209927B2 (en) | 2007-12-20 | 2012-07-03 | James Hardie Technology Limited | Structural fiber cement building materials |
US7977531B2 (en) * | 2008-01-30 | 2011-07-12 | Kimberly-Clark Worldwide, Inc. | Absorbent articles comprising absorbent materials exhibiting deswell/reswell |
US8641869B2 (en) * | 2008-06-30 | 2014-02-04 | Weyerhaeuser Nr Company | Method for making biodegradable superabsorbent particles |
US20090325797A1 (en) * | 2008-06-30 | 2009-12-31 | Weyerhaeuser Co. | Biodegradable Superabsorbent Particles |
US8101543B2 (en) * | 2008-06-30 | 2012-01-24 | Weyerhaeuser Nr Company | Biodegradable superabsorbent particles |
US7833384B2 (en) * | 2008-06-30 | 2010-11-16 | Weyerhaeuser Nr Company | Method for making fiber having biodegradable superabsorbent particles attached thereto |
US20090326180A1 (en) * | 2008-06-30 | 2009-12-31 | Weyerhaeuser Co. | Biodegradable Superabsorbent Particles Containing Cellulose Fiber |
US8084391B2 (en) * | 2008-06-30 | 2011-12-27 | Weyerhaeuser Nr Company | Fibers having biodegradable superabsorbent particles attached thereto |
US7959762B2 (en) * | 2008-06-30 | 2011-06-14 | Weyerhaeuser Nr Company | Method for making biodegradable superabsorbent particles |
PL213595B1 (en) * | 2008-09-29 | 2013-03-29 | Borkowski Marek | A fabric, preferably for manufacturing of sterile dressings |
US9512237B2 (en) | 2009-05-28 | 2016-12-06 | Gp Cellulose Gmbh | Method for inhibiting the growth of microbes with a modified cellulose fiber |
US9511167B2 (en) | 2009-05-28 | 2016-12-06 | Gp Cellulose Gmbh | Modified cellulose from chemical kraft fiber and methods of making and using the same |
US9512563B2 (en) | 2009-05-28 | 2016-12-06 | Gp Cellulose Gmbh | Surface treated modified cellulose from chemical kraft fiber and methods of making and using same |
ES2752755T3 (en) | 2009-05-28 | 2020-04-06 | Gp Cellulose Gmbh | Kraft chemical fiber modified cellulose and methods of production and use thereof |
ES2955492T3 (en) | 2009-08-05 | 2023-12-01 | Int Paper Co | Process for applying a composition containing a cationic trivalent metal and a release agent and fluff pulp sheet manufactured therefrom |
CA2770082C (en) | 2009-08-05 | 2014-09-30 | International Paper Company | Dry fluff pulp sheet additive |
MY162376A (en) * | 2009-08-05 | 2017-06-15 | Shell Int Research | Method for monitoring a well |
CN102548654A (en) | 2009-09-29 | 2012-07-04 | 株式会社日本触媒 | Particulate water absorbent and process for production thereof |
US8328988B2 (en) * | 2010-03-15 | 2012-12-11 | Weyerhaeuser Nr Company | Reduction of the adsorption of quaternary ammonium salts onto cellulosic fibers |
US8465624B2 (en) | 2010-07-20 | 2013-06-18 | International Paper Company | Composition containing a multivalent cationic metal and amine-containing anti-static agent and methods of making and using |
CN103003488B (en) | 2010-07-22 | 2015-04-15 | 国际纸业公司 | Process for preparing fluff pulp sheet with cationic dye and debonder surfactant and fluff pulp sheet made from same |
WO2013007973A2 (en) | 2011-07-14 | 2013-01-17 | Smith & Nephew Plc | Wound dressing and method of treatment |
US9005738B2 (en) | 2010-12-08 | 2015-04-14 | Buckeye Technologies Inc. | Dispersible nonwoven wipe material |
JP5679895B2 (en) * | 2011-04-28 | 2015-03-04 | Esファイバービジョンズ株式会社 | Fiber with improved discoloration resistance, and fiber molded body comprising the same |
EP3650055A1 (en) | 2012-05-23 | 2020-05-13 | Smith & Nephew plc | Apparatuses and methods for negative pressure wound therapy |
DK2879636T3 (en) | 2012-08-01 | 2017-06-19 | Smith & Nephew | Wound dressing |
EP2879635A2 (en) | 2012-08-01 | 2015-06-10 | Smith & Nephew PLC | Wound dressing and method of treatment |
US9237976B2 (en) * | 2013-01-30 | 2016-01-19 | Cornerstone Research Group, Inc. | Fluid absorption and distribution enhancement systems |
US9951470B2 (en) | 2013-03-15 | 2018-04-24 | Gp Cellulose Gmbh | Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same |
US20140259491A1 (en) * | 2013-03-15 | 2014-09-18 | Ez Products Of South Florida L.L.C. | Multi-layered cleaning cloth |
US9375507B2 (en) | 2013-04-10 | 2016-06-28 | Evonik Corporation | Particulate superabsorbent polymer composition having improved stability |
US9302248B2 (en) | 2013-04-10 | 2016-04-05 | Evonik Corporation | Particulate superabsorbent polymer composition having improved stability |
EP3068618B1 (en) | 2013-11-15 | 2018-04-25 | Georgia-Pacific Nonwovens LLC | Dispersible nonwoven wipe material |
US9717817B2 (en) * | 2013-12-30 | 2017-08-01 | International Paper Company | Binary odor control system for absorbent articles |
JP6199243B2 (en) | 2014-06-12 | 2017-09-20 | ユニ・チャーム株式会社 | Method for producing recycled pulp from used sanitary products |
CA2952284C (en) | 2014-06-18 | 2023-03-28 | Smith & Nephew Plc | Wound dressing |
GB2548707B (en) * | 2014-07-28 | 2020-09-16 | Indian Institute Of Tech Hyderabad | Cellulose acetate based non-woven nanofiber matrix with high absorbency properties for female hygiene products |
US11840797B1 (en) | 2014-11-26 | 2023-12-12 | Microban Products Company | Textile formulation and product with odor control |
CA2986091C (en) | 2015-04-03 | 2023-10-10 | Resolute Fp Us Inc. | Methods for producing a cellulosic fiber having a high curl index and acquisition and distribution layer containing same |
GB2555584B (en) | 2016-10-28 | 2020-05-27 | Smith & Nephew | Multi-layered wound dressing and method of manufacture |
US20190367851A1 (en) | 2017-01-12 | 2019-12-05 | Georgia-Pacific Nonwovens LLC | Nonwoven material for cleaning and sanitizing surfaces |
WO2019067487A1 (en) | 2017-09-27 | 2019-04-04 | Georgia-Pacific Nonwovens LLC | Nonwoven air filtration medium |
US11806976B2 (en) | 2017-09-27 | 2023-11-07 | Glatfelter Corporation | Nonwoven material with high core bicomponent fibers |
ES2925308T3 (en) | 2018-03-12 | 2022-10-14 | Georgia Pacific Mt Holly Llc | Non-woven material with high-core bicomponent fibers |
CN109457388A (en) * | 2018-10-24 | 2019-03-12 | 南六企业(平湖)有限公司 | A kind of processing technology of the weak acid pro-skin hot-wind nonwoven cloth with antibiotic effect |
JP6643455B1 (en) * | 2018-11-09 | 2020-02-12 | ユニ・チャーム株式会社 | Method for producing pulp fiber for making cellulose nanofiber |
JP6925315B2 (en) * | 2018-12-31 | 2021-08-25 | ユニ・チャーム株式会社 | Method for producing pulp fiber for medium, pulp fiber for medium, and use of pulp fiber for medium |
CN112955604A (en) * | 2018-11-09 | 2021-06-11 | 尤妮佳股份有限公司 | Method for producing recycled pulp fibers, and use of ozone |
EP3862484A4 (en) * | 2018-11-09 | 2022-01-26 | Unicharm Corporation | Method for producing recycled pulp fibers, recycled pulp fibers, and use for ozone |
JP2020109224A (en) * | 2018-12-31 | 2020-07-16 | ユニ・チャーム株式会社 | Method for producing pulp fiber raw material and pulp fiber raw material as cellulose raw material |
EP4010524B1 (en) | 2019-08-08 | 2024-03-06 | Glatfelter Corporation | Dispersible nonwoven materials including cmc-based binders |
CN111691063A (en) * | 2020-07-12 | 2020-09-22 | 常熟市神马纺织品有限公司 | Processing technology of water-punched non-woven fabric for cotton soft towel |
Citations (87)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US213100A (en) * | 1879-03-11 | Improvement in preparing paper and other fabrics and materials for protecting metals | ||
US1571048A (en) * | 1926-01-26 | Ments | ||
US1990292A (en) * | 1933-01-16 | 1935-02-05 | Leatherman Martin | Process for fireproofing cellulosic materials |
US2032645A (en) * | 1933-08-18 | 1936-03-03 | Northern Paper Mills | Absorbent paper product and process of producing the same |
US2097589A (en) * | 1934-08-30 | 1937-11-02 | Dreyfus Henry | Treatment of textile materials |
US2289282A (en) * | 1938-11-05 | 1942-07-07 | Gen Aniline & Film Corp | Method of delustering |
US2525049A (en) * | 1946-08-22 | 1950-10-10 | Du Pont | Cellulose titanate film production |
US2739871A (en) * | 1950-09-15 | 1956-03-27 | Daubert Chemical Co | Composition and sheet material for inhibition of corrosion of metals |
US2983722A (en) * | 1957-11-06 | 1961-05-09 | Yardney International Corp | Fungicidal compounds |
US3053607A (en) * | 1958-06-02 | 1962-09-11 | Du Pont | Process of making wool-like cellulosic textile materials |
US3224926A (en) * | 1962-06-22 | 1965-12-21 | Kimberly Clark Co | Method of forming cross-linked cellulosic fibers and product thereof |
US3873354A (en) * | 1972-03-24 | 1975-03-25 | Preco Corp | Electrostatic printing |
US3935363A (en) * | 1974-09-16 | 1976-01-27 | The Dow Chemical Company | Absorbent product containing flocculated clay mineral aggregates |
US3998690A (en) * | 1972-10-02 | 1976-12-21 | The Procter & Gamble Company | Fibrous assemblies from cationically and anionically charged fibers |
US4043952A (en) * | 1975-05-09 | 1977-08-23 | National Starch And Chemical Corporation | Surface treatment process for improving dispersibility of an absorbent composition, and product thereof |
US4090013A (en) * | 1975-03-07 | 1978-05-16 | National Starch And Chemical Corp. | Absorbent composition of matter |
US4102340A (en) * | 1974-12-09 | 1978-07-25 | Johnson & Johnson | Disposable article with particulate hydrophilic polymer in an absorbent bed |
US4295987A (en) * | 1979-12-26 | 1981-10-20 | The Procter & Gamble Company | Cross-linked sodium polyacrylate absorbent |
US4302369A (en) * | 1980-04-08 | 1981-11-24 | Henkel Corporation | Aluminum modified water absorbent composition |
US4306911A (en) * | 1979-02-09 | 1981-12-22 | Amiantus, (A.G.) | Method for the production of a fiber-reinforced hydraulically setting material |
US4406703A (en) * | 1980-02-04 | 1983-09-27 | Permawood International Corporation | Composite materials made from plant fibers bonded with portland cement and method of producing same |
US4447570A (en) * | 1982-03-01 | 1984-05-08 | Air Products And Chemicals, Inc. | Binder compositions for making nonwoven fabrics having good hydrophobic rewet properties |
US4467012A (en) * | 1981-08-05 | 1984-08-21 | Grain Processing Corporation | Composition for absorbent film and method of preparation |
US4469746A (en) * | 1982-06-01 | 1984-09-04 | The Procter & Gamble Company | Silica coated absorbent fibers |
US4558091A (en) * | 1983-05-13 | 1985-12-10 | Grain Processing Corporation | Method for preparing aluminum and polyhydric alcohol modified liquid absorbing composition |
US4699823A (en) * | 1985-08-21 | 1987-10-13 | Kimberly-Clark Corporation | Non-layered absorbent insert having Z-directional superabsorbent concentration gradient |
US4715931A (en) * | 1987-03-24 | 1987-12-29 | Betz Laboratories, Inc. | Process for inhibiting aluminum hydroxide deposition in papermaking felts |
USRE32649E (en) * | 1985-06-18 | 1988-04-19 | The Procter & Gamble Company | Hydrogel-forming polymer compositions for use in absorbent structures |
US4838885A (en) * | 1985-09-06 | 1989-06-13 | Kimberly-Clark Corporation | Form-fitting self-adjusting disposable garment with a multilayered absorbent |
US4888238A (en) * | 1987-09-16 | 1989-12-19 | James River Corporation | Superabsorbent coated fibers and method for their preparation |
US4898642A (en) * | 1986-06-27 | 1990-02-06 | The Procter & Gamble Cellulose Company | Twisted, chemically stiffened cellulosic fibers and absorbent structures made therefrom |
US4919681A (en) * | 1988-02-16 | 1990-04-24 | Basf Corporation | Method of preparing cellulosic fibers having increased absorbency |
US4935022A (en) * | 1988-02-11 | 1990-06-19 | The Procter & Gamble Company | Thin absorbent articles containing gelling agent |
US4950264A (en) * | 1988-03-31 | 1990-08-21 | The Procter & Gamble Company | Thin, flexible sanitary napkin |
US4950265A (en) * | 1988-10-17 | 1990-08-21 | Hart Enterprises, Inc. | Arming device for a medical instrument |
US4952550A (en) * | 1989-03-09 | 1990-08-28 | Micro Vesicular Systems, Inc. | Particulate absorbent material |
US5147343A (en) * | 1988-04-21 | 1992-09-15 | Kimberly-Clark Corporation | Absorbent products containing hydrogels with ability to swell against pressure |
US5149335A (en) * | 1990-02-23 | 1992-09-22 | Kimberly-Clark Corporation | Absorbent structure |
US5190563A (en) * | 1989-11-07 | 1993-03-02 | The Proctor & Gamble Co. | Process for preparing individualized, polycarboxylic acid crosslinked fibers |
US5217445A (en) * | 1990-01-23 | 1993-06-08 | The Procter & Gamble Company | Absorbent structures containing superabsorbent material and web of wetlaid stiffened fibers |
US5294299A (en) * | 1988-11-07 | 1994-03-15 | Manfred Zeuner | Paper, cardboard or paperboard-like material and a process for its production |
US5300192A (en) * | 1992-08-17 | 1994-04-05 | Weyerhaeuser Company | Wet laid fiber sheet manufacturing with reactivatable binders for binding particles to fibers |
US5328935A (en) * | 1993-03-26 | 1994-07-12 | The Procter & Gamble Company | Method of makig a superabsorbent polymer foam |
US5338766A (en) * | 1993-03-26 | 1994-08-16 | The Procter & Gamble Company | Superabsorbent polymer foam |
US5350799A (en) * | 1990-05-31 | 1994-09-27 | Hoechst Celanese Corporation | Process for the conversion of fine superabsorbent polymer particles into larger particles |
US5360420A (en) * | 1990-01-23 | 1994-11-01 | The Procter & Gamble Company | Absorbent structures containing stiffened fibers and superabsorbent material |
US5372766A (en) * | 1994-03-31 | 1994-12-13 | The Procter & Gamble Company | Flexible, porous, absorbent, polymeric macrostructures and methods of making the same |
US5399591A (en) * | 1993-09-17 | 1995-03-21 | Nalco Chemical Company | Superabsorbent polymer having improved absorption rate and absorption under pressure |
US5413676A (en) * | 1992-07-22 | 1995-05-09 | Chicopee | Cellulosic fiber of improved wettability |
US5417977A (en) * | 1989-12-14 | 1995-05-23 | Isolyser Co., Inc. | Method of producing an absorbent composition |
US5427844A (en) * | 1991-06-12 | 1995-06-27 | New Japan Chemical Co., Ltd. | Articles of natural cellulose fibers with improved deodorant properties and process for producing same |
US5432000A (en) * | 1989-03-20 | 1995-07-11 | Weyerhaeuser Company | Binder coated discontinuous fibers with adhered particulate materials |
US5451613A (en) * | 1993-09-17 | 1995-09-19 | Nalco Chemical Company | Superabsorbent polymer having improved absorption rate and absorption under pressure |
US5484896A (en) * | 1994-03-24 | 1996-01-16 | The Procter & Gamble Company | Esterified high lignin content cellulosic fibers |
US5489469A (en) * | 1987-01-28 | 1996-02-06 | Kao Corporation | Absorbent composite |
US5492759A (en) * | 1989-09-27 | 1996-02-20 | Molnlycke Ab | Fibres of increased specific surface area, a method for their manufacture, fluff pulp consisting of such fibres and the use of the fibres as absorption material |
US5506684A (en) * | 1991-04-04 | 1996-04-09 | Nikon Corporation | Projection scanning exposure apparatus with synchronous mask/wafer alignment system |
US5548847A (en) * | 1994-12-09 | 1996-08-27 | Spicijaric; John | Cap with a picture retaining pocket |
US5562646A (en) * | 1994-03-29 | 1996-10-08 | The Proctor & Gamble Company | Absorbent members for body fluids having good wet integrity and relatively high concentrations of hydrogel-forming absorbent polymer having high porosity |
US5562642A (en) * | 1992-12-07 | 1996-10-08 | Creative Products Resource, Inc. | Separately packaged applicator pads for topical delivery of incompatible drugs |
US5589256A (en) * | 1992-08-17 | 1996-12-31 | Weyerhaeuser Company | Particle binders that enhance fiber densification |
US5601921A (en) * | 1989-09-27 | 1997-02-11 | Molnlycke Ab | Aluminium-salt impregnated fibres, a method for their manufacture, fluff consisting of such fibres, and the use of the fibres as absorption material |
US5611890A (en) * | 1995-04-07 | 1997-03-18 | The Proctor & Gamble Company | Tissue paper containing a fine particulate filler |
US5721295A (en) * | 1992-03-05 | 1998-02-24 | Chemische Fabrik Stockhausen Gmbh | Polymer composition, absorbent composition, their production and use |
US5736595A (en) * | 1993-05-03 | 1998-04-07 | Chemische Fabrik Stockhausen Gmbh | Polymer composition, absorbent material composition, their production and their use |
US5773542A (en) * | 1995-03-23 | 1998-06-30 | Kao Corporation | Process for producing polymer particles |
US5789326A (en) * | 1992-08-17 | 1998-08-04 | Weyerhaeuser Company | Particle binders |
US5795515A (en) * | 1995-08-16 | 1998-08-18 | Nueva Ag | Method of producing formed articles of a fiber reinforced, hydraulically setting material |
US5795439A (en) * | 1997-01-31 | 1998-08-18 | Celanese Acetate Llc | Process for making a non-woven, wet-laid, superabsorbent polymer-impregnated structure |
US5847031A (en) * | 1993-05-03 | 1998-12-08 | Chemische Fabrik Stockhausen Gmbh | Polymer composition, absorbent composition, their production and use |
US5849816A (en) * | 1994-08-01 | 1998-12-15 | Leonard Pearlstein | Method of making high performance superabsorbent material |
US5858021A (en) * | 1996-10-31 | 1999-01-12 | Kimberly-Clark Worldwide, Inc. | Treatment process for cellulosic fibers |
US5859077A (en) * | 1995-12-19 | 1999-01-12 | Nova-Sorb Ltd. Novel Absorbents | Apparatus and method for producing porous superabsorbent materials |
US5961505A (en) * | 1991-07-17 | 1999-10-05 | Kimberly-Clark-Worldwide, Inc. | Absorbent article exhibiting improved fluid management |
US5998695A (en) * | 1998-06-29 | 1999-12-07 | The Procter & Gamble Company | Absorbent article including ionic complexing agent for feces |
US6040251A (en) * | 1988-03-14 | 2000-03-21 | Nextec Applications Inc. | Garments of barrier webs |
US6074530A (en) * | 1998-01-21 | 2000-06-13 | Vinings Industries, Inc. | Method for enhancing the anti-skid or friction properties of a cellulosic fiber |
US6080277A (en) * | 1995-02-21 | 2000-06-27 | Tfm Handels-Aktiengesellschaft | Cellulose particles, method for producing them and their use |
US6099950A (en) * | 1994-02-17 | 2000-08-08 | The Procter & Gamble Company | Absorbent materials having improved absorbent property and methods for making the same |
US6127593A (en) * | 1997-11-25 | 2000-10-03 | The Procter & Gamble Company | Flushable fibrous structures |
US6159335A (en) * | 1997-02-21 | 2000-12-12 | Buckeye Technologies Inc. | Method for treating pulp to reduce disintegration energy |
US6222091B1 (en) * | 1997-11-19 | 2001-04-24 | Basf Aktiengesellschaft | Multicomponent superabsorbent gel particles |
US6228217B1 (en) * | 1995-01-13 | 2001-05-08 | Hercules Incorporated | Strength of paper made from pulp containing surface active, carboxyl compounds |
US6235965B1 (en) * | 1997-11-19 | 2001-05-22 | Basf Aktiengesellschaft | Multicomponent superabsorbent gel particles |
US6296737B1 (en) * | 1996-10-23 | 2001-10-02 | Weyerhaeuser Company | Method of making readily debonded pulp products |
US6340408B1 (en) * | 1996-04-15 | 2002-01-22 | Stora Kopparbergs Bergslags Aktiebolag (Publ) | Method of preparation of a fluffed pulp to be used in absorbent products |
US6433058B1 (en) * | 1999-12-07 | 2002-08-13 | Dow Global Technologies Inc. | Superabsorbent polymers having a slow rate of absorption |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4506684A (en) | 1978-08-02 | 1985-03-26 | Philip Morris Incorporated | Modified cellulosic smoking material and method for its preparation |
SE8106885L (en) | 1981-11-19 | 1983-05-20 | Alby Klorat Ab | CHEMICAL MASS WITH IMPROVED STRENGTH, DRAINAGE FORM, AND PAINTABILITY AND SET TO MAKE IT |
US4548847A (en) | 1984-01-09 | 1985-10-22 | Kimberly-Clark Corporation | Delayed-swelling absorbent systems |
JPS6245775A (en) * | 1985-08-26 | 1987-02-27 | ダイセル化学工業株式会社 | Deodorizing fiber web |
JPH0253965A (en) * | 1988-08-19 | 1990-02-22 | Nippon Shokubai Kagaku Kogyo Co Ltd | Fixing of water-absorbing polymer to fibrous substrate |
JP2613934B2 (en) * | 1988-12-08 | 1997-05-28 | 株式会社日本触媒 | Method for producing water-absorbing composite |
SE462918B (en) | 1989-01-25 | 1990-09-17 | Stora Kopparbergs Bergslags Ab | Method for production of fluff pulp |
JP2954360B2 (en) * | 1990-12-12 | 1999-09-27 | 三菱化学株式会社 | Manufacturing method of water-absorbing composite |
JP3330716B2 (en) | 1994-02-16 | 2002-09-30 | 三菱化学株式会社 | Superabsorbent polymer composition |
JP3445426B2 (en) | 1995-12-26 | 2003-09-08 | 花王株式会社 | Super water absorbent resin composition |
JPH10489A (en) | 1996-06-13 | 1998-01-06 | Sumitomo Seika Chem Co Ltd | Drainage treatment method |
JP3205529B2 (en) | 1997-01-31 | 2001-09-04 | 花王株式会社 | Super water absorbent resin composition |
EP0979250B1 (en) * | 1997-04-29 | 2004-04-14 | Dow Global Technologies Inc. | Superabsorbent polymers having improved processability |
US6300275B1 (en) * | 1997-04-29 | 2001-10-09 | The Dow Chemical Company | Resilient superabsorbent compositions |
SG86324A1 (en) | 1997-07-03 | 2002-02-19 | Kao Corp | Superabsorbent resin composition |
SE511857C2 (en) | 1998-04-28 | 1999-12-06 | Sca Hygiene Prod Ab | Absorbent structure with improved absorption properties containing at least 50% by weight superabsorbent material |
WO1999055767A1 (en) | 1998-04-28 | 1999-11-04 | Basf Aktiengesellschaft | Mechanically stable hydrogels |
-
1999
- 1999-12-21 US US09/469,930 patent/US6562743B1/en not_active Expired - Lifetime
- 1999-12-22 JP JP2000590561A patent/JP2003523484A/en active Pending
- 1999-12-22 CA CA002356651A patent/CA2356651C/en not_active Expired - Lifetime
- 1999-12-22 AU AU23842/00A patent/AU759840B2/en not_active Expired
- 1999-12-22 CN CNB998149861A patent/CN1281202C/en not_active Expired - Lifetime
- 1999-12-22 BR BRPI9917115-5A patent/BR9917115B1/en not_active IP Right Cessation
- 1999-12-22 ES ES99967581T patent/ES2388031T3/en not_active Expired - Lifetime
- 1999-12-22 WO PCT/US1999/030791 patent/WO2000038607A1/en not_active Application Discontinuation
- 1999-12-22 AT AT99967581T patent/ATE551978T1/en active
- 1999-12-22 EP EP19990967581 patent/EP1139961B1/en not_active Expired - Lifetime
- 1999-12-22 EP EP11185196.0A patent/EP2407135B1/en not_active Expired - Lifetime
- 1999-12-22 KR KR1020017007916A patent/KR20010089673A/en not_active Application Discontinuation
- 1999-12-23 AR ARP990106747 patent/AR029448A1/en active IP Right Grant
- 1999-12-23 PE PE1999001317A patent/PE20001307A1/en not_active Application Discontinuation
-
2000
- 2000-02-19 TW TW88122796A patent/TWI232744B/en not_active IP Right Cessation
-
2003
- 2003-02-07 US US10/360,147 patent/US6770576B2/en not_active Expired - Lifetime
-
2004
- 2004-06-10 US US10/866,210 patent/US20040224588A1/en not_active Abandoned
- 2004-07-30 AR ARP040102731 patent/AR045182A2/en unknown
- 2004-07-30 AR ARP040102730 patent/AR045181A2/en active IP Right Grant
Patent Citations (89)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US213100A (en) * | 1879-03-11 | Improvement in preparing paper and other fabrics and materials for protecting metals | ||
US1571048A (en) * | 1926-01-26 | Ments | ||
US1990292A (en) * | 1933-01-16 | 1935-02-05 | Leatherman Martin | Process for fireproofing cellulosic materials |
US2032645A (en) * | 1933-08-18 | 1936-03-03 | Northern Paper Mills | Absorbent paper product and process of producing the same |
US2097589A (en) * | 1934-08-30 | 1937-11-02 | Dreyfus Henry | Treatment of textile materials |
US2289282A (en) * | 1938-11-05 | 1942-07-07 | Gen Aniline & Film Corp | Method of delustering |
US2525049A (en) * | 1946-08-22 | 1950-10-10 | Du Pont | Cellulose titanate film production |
US2739871A (en) * | 1950-09-15 | 1956-03-27 | Daubert Chemical Co | Composition and sheet material for inhibition of corrosion of metals |
US2983722A (en) * | 1957-11-06 | 1961-05-09 | Yardney International Corp | Fungicidal compounds |
US3053607A (en) * | 1958-06-02 | 1962-09-11 | Du Pont | Process of making wool-like cellulosic textile materials |
US3224926A (en) * | 1962-06-22 | 1965-12-21 | Kimberly Clark Co | Method of forming cross-linked cellulosic fibers and product thereof |
US3873354A (en) * | 1972-03-24 | 1975-03-25 | Preco Corp | Electrostatic printing |
US3998690A (en) * | 1972-10-02 | 1976-12-21 | The Procter & Gamble Company | Fibrous assemblies from cationically and anionically charged fibers |
US3935363A (en) * | 1974-09-16 | 1976-01-27 | The Dow Chemical Company | Absorbent product containing flocculated clay mineral aggregates |
US4102340A (en) * | 1974-12-09 | 1978-07-25 | Johnson & Johnson | Disposable article with particulate hydrophilic polymer in an absorbent bed |
US4090013A (en) * | 1975-03-07 | 1978-05-16 | National Starch And Chemical Corp. | Absorbent composition of matter |
US4043952A (en) * | 1975-05-09 | 1977-08-23 | National Starch And Chemical Corporation | Surface treatment process for improving dispersibility of an absorbent composition, and product thereof |
US4306911A (en) * | 1979-02-09 | 1981-12-22 | Amiantus, (A.G.) | Method for the production of a fiber-reinforced hydraulically setting material |
US4295987A (en) * | 1979-12-26 | 1981-10-20 | The Procter & Gamble Company | Cross-linked sodium polyacrylate absorbent |
US4406703A (en) * | 1980-02-04 | 1983-09-27 | Permawood International Corporation | Composite materials made from plant fibers bonded with portland cement and method of producing same |
US4302369A (en) * | 1980-04-08 | 1981-11-24 | Henkel Corporation | Aluminum modified water absorbent composition |
US4467012A (en) * | 1981-08-05 | 1984-08-21 | Grain Processing Corporation | Composition for absorbent film and method of preparation |
US4447570A (en) * | 1982-03-01 | 1984-05-08 | Air Products And Chemicals, Inc. | Binder compositions for making nonwoven fabrics having good hydrophobic rewet properties |
US4469746A (en) * | 1982-06-01 | 1984-09-04 | The Procter & Gamble Company | Silica coated absorbent fibers |
US4558091A (en) * | 1983-05-13 | 1985-12-10 | Grain Processing Corporation | Method for preparing aluminum and polyhydric alcohol modified liquid absorbing composition |
USRE32649E (en) * | 1985-06-18 | 1988-04-19 | The Procter & Gamble Company | Hydrogel-forming polymer compositions for use in absorbent structures |
US4699823A (en) * | 1985-08-21 | 1987-10-13 | Kimberly-Clark Corporation | Non-layered absorbent insert having Z-directional superabsorbent concentration gradient |
US4838885A (en) * | 1985-09-06 | 1989-06-13 | Kimberly-Clark Corporation | Form-fitting self-adjusting disposable garment with a multilayered absorbent |
US4898642A (en) * | 1986-06-27 | 1990-02-06 | The Procter & Gamble Cellulose Company | Twisted, chemically stiffened cellulosic fibers and absorbent structures made therefrom |
US5489469A (en) * | 1987-01-28 | 1996-02-06 | Kao Corporation | Absorbent composite |
US4715931A (en) * | 1987-03-24 | 1987-12-29 | Betz Laboratories, Inc. | Process for inhibiting aluminum hydroxide deposition in papermaking felts |
US4888238A (en) * | 1987-09-16 | 1989-12-19 | James River Corporation | Superabsorbent coated fibers and method for their preparation |
US4935022A (en) * | 1988-02-11 | 1990-06-19 | The Procter & Gamble Company | Thin absorbent articles containing gelling agent |
US4919681A (en) * | 1988-02-16 | 1990-04-24 | Basf Corporation | Method of preparing cellulosic fibers having increased absorbency |
US6040251A (en) * | 1988-03-14 | 2000-03-21 | Nextec Applications Inc. | Garments of barrier webs |
US4950264A (en) * | 1988-03-31 | 1990-08-21 | The Procter & Gamble Company | Thin, flexible sanitary napkin |
US5147343A (en) * | 1988-04-21 | 1992-09-15 | Kimberly-Clark Corporation | Absorbent products containing hydrogels with ability to swell against pressure |
US5147343B1 (en) * | 1988-04-21 | 1998-03-17 | Kimberly Clark Co | Absorbent products containing hydrogels with ability to swell against pressure |
US4950265A (en) * | 1988-10-17 | 1990-08-21 | Hart Enterprises, Inc. | Arming device for a medical instrument |
US5294299A (en) * | 1988-11-07 | 1994-03-15 | Manfred Zeuner | Paper, cardboard or paperboard-like material and a process for its production |
US4952550A (en) * | 1989-03-09 | 1990-08-28 | Micro Vesicular Systems, Inc. | Particulate absorbent material |
US5432000A (en) * | 1989-03-20 | 1995-07-11 | Weyerhaeuser Company | Binder coated discontinuous fibers with adhered particulate materials |
US5601921A (en) * | 1989-09-27 | 1997-02-11 | Molnlycke Ab | Aluminium-salt impregnated fibres, a method for their manufacture, fluff consisting of such fibres, and the use of the fibres as absorption material |
US5492759A (en) * | 1989-09-27 | 1996-02-20 | Molnlycke Ab | Fibres of increased specific surface area, a method for their manufacture, fluff pulp consisting of such fibres and the use of the fibres as absorption material |
US5190563A (en) * | 1989-11-07 | 1993-03-02 | The Proctor & Gamble Co. | Process for preparing individualized, polycarboxylic acid crosslinked fibers |
US5417977A (en) * | 1989-12-14 | 1995-05-23 | Isolyser Co., Inc. | Method of producing an absorbent composition |
US5217445A (en) * | 1990-01-23 | 1993-06-08 | The Procter & Gamble Company | Absorbent structures containing superabsorbent material and web of wetlaid stiffened fibers |
US5360420A (en) * | 1990-01-23 | 1994-11-01 | The Procter & Gamble Company | Absorbent structures containing stiffened fibers and superabsorbent material |
US5149335A (en) * | 1990-02-23 | 1992-09-22 | Kimberly-Clark Corporation | Absorbent structure |
US5350799A (en) * | 1990-05-31 | 1994-09-27 | Hoechst Celanese Corporation | Process for the conversion of fine superabsorbent polymer particles into larger particles |
US5506684A (en) * | 1991-04-04 | 1996-04-09 | Nikon Corporation | Projection scanning exposure apparatus with synchronous mask/wafer alignment system |
US5427844A (en) * | 1991-06-12 | 1995-06-27 | New Japan Chemical Co., Ltd. | Articles of natural cellulose fibers with improved deodorant properties and process for producing same |
US5961505A (en) * | 1991-07-17 | 1999-10-05 | Kimberly-Clark-Worldwide, Inc. | Absorbent article exhibiting improved fluid management |
US5721295A (en) * | 1992-03-05 | 1998-02-24 | Chemische Fabrik Stockhausen Gmbh | Polymer composition, absorbent composition, their production and use |
US5413676A (en) * | 1992-07-22 | 1995-05-09 | Chicopee | Cellulosic fiber of improved wettability |
US5300192A (en) * | 1992-08-17 | 1994-04-05 | Weyerhaeuser Company | Wet laid fiber sheet manufacturing with reactivatable binders for binding particles to fibers |
US5789326A (en) * | 1992-08-17 | 1998-08-04 | Weyerhaeuser Company | Particle binders |
US5589256A (en) * | 1992-08-17 | 1996-12-31 | Weyerhaeuser Company | Particle binders that enhance fiber densification |
US5562642A (en) * | 1992-12-07 | 1996-10-08 | Creative Products Resource, Inc. | Separately packaged applicator pads for topical delivery of incompatible drugs |
US5338766A (en) * | 1993-03-26 | 1994-08-16 | The Procter & Gamble Company | Superabsorbent polymer foam |
US5328935A (en) * | 1993-03-26 | 1994-07-12 | The Procter & Gamble Company | Method of makig a superabsorbent polymer foam |
US5847031A (en) * | 1993-05-03 | 1998-12-08 | Chemische Fabrik Stockhausen Gmbh | Polymer composition, absorbent composition, their production and use |
US5736595A (en) * | 1993-05-03 | 1998-04-07 | Chemische Fabrik Stockhausen Gmbh | Polymer composition, absorbent material composition, their production and their use |
US5399591A (en) * | 1993-09-17 | 1995-03-21 | Nalco Chemical Company | Superabsorbent polymer having improved absorption rate and absorption under pressure |
US5451613A (en) * | 1993-09-17 | 1995-09-19 | Nalco Chemical Company | Superabsorbent polymer having improved absorption rate and absorption under pressure |
US5462972A (en) * | 1993-09-17 | 1995-10-31 | Nalco Chemical Company | Superabsorbent polymer having improved absorption rate and absorption under pressure |
US6099950A (en) * | 1994-02-17 | 2000-08-08 | The Procter & Gamble Company | Absorbent materials having improved absorbent property and methods for making the same |
US5484896A (en) * | 1994-03-24 | 1996-01-16 | The Procter & Gamble Company | Esterified high lignin content cellulosic fibers |
US5562646A (en) * | 1994-03-29 | 1996-10-08 | The Proctor & Gamble Company | Absorbent members for body fluids having good wet integrity and relatively high concentrations of hydrogel-forming absorbent polymer having high porosity |
US5372766A (en) * | 1994-03-31 | 1994-12-13 | The Procter & Gamble Company | Flexible, porous, absorbent, polymeric macrostructures and methods of making the same |
US5849816A (en) * | 1994-08-01 | 1998-12-15 | Leonard Pearlstein | Method of making high performance superabsorbent material |
US5548847A (en) * | 1994-12-09 | 1996-08-27 | Spicijaric; John | Cap with a picture retaining pocket |
US6228217B1 (en) * | 1995-01-13 | 2001-05-08 | Hercules Incorporated | Strength of paper made from pulp containing surface active, carboxyl compounds |
US6080277A (en) * | 1995-02-21 | 2000-06-27 | Tfm Handels-Aktiengesellschaft | Cellulose particles, method for producing them and their use |
US5773542A (en) * | 1995-03-23 | 1998-06-30 | Kao Corporation | Process for producing polymer particles |
US5611890A (en) * | 1995-04-07 | 1997-03-18 | The Proctor & Gamble Company | Tissue paper containing a fine particulate filler |
US5795515A (en) * | 1995-08-16 | 1998-08-18 | Nueva Ag | Method of producing formed articles of a fiber reinforced, hydraulically setting material |
US5859077A (en) * | 1995-12-19 | 1999-01-12 | Nova-Sorb Ltd. Novel Absorbents | Apparatus and method for producing porous superabsorbent materials |
US6340408B1 (en) * | 1996-04-15 | 2002-01-22 | Stora Kopparbergs Bergslags Aktiebolag (Publ) | Method of preparation of a fluffed pulp to be used in absorbent products |
US6296737B1 (en) * | 1996-10-23 | 2001-10-02 | Weyerhaeuser Company | Method of making readily debonded pulp products |
US5858021A (en) * | 1996-10-31 | 1999-01-12 | Kimberly-Clark Worldwide, Inc. | Treatment process for cellulosic fibers |
US5795439A (en) * | 1997-01-31 | 1998-08-18 | Celanese Acetate Llc | Process for making a non-woven, wet-laid, superabsorbent polymer-impregnated structure |
US6159335A (en) * | 1997-02-21 | 2000-12-12 | Buckeye Technologies Inc. | Method for treating pulp to reduce disintegration energy |
US6222091B1 (en) * | 1997-11-19 | 2001-04-24 | Basf Aktiengesellschaft | Multicomponent superabsorbent gel particles |
US6235965B1 (en) * | 1997-11-19 | 2001-05-22 | Basf Aktiengesellschaft | Multicomponent superabsorbent gel particles |
US6127593A (en) * | 1997-11-25 | 2000-10-03 | The Procter & Gamble Company | Flushable fibrous structures |
US6074530A (en) * | 1998-01-21 | 2000-06-13 | Vinings Industries, Inc. | Method for enhancing the anti-skid or friction properties of a cellulosic fiber |
US5998695A (en) * | 1998-06-29 | 1999-12-07 | The Procter & Gamble Company | Absorbent article including ionic complexing agent for feces |
US6433058B1 (en) * | 1999-12-07 | 2002-08-13 | Dow Global Technologies Inc. | Superabsorbent polymers having a slow rate of absorption |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8946100B2 (en) | 2003-12-19 | 2015-02-03 | Buckeye Technologies Inc. | Fibers of variable wettability and materials containing the fibers |
US10300457B2 (en) | 2003-12-19 | 2019-05-28 | Georgia-Pacific Nonwovens LLC | Fibers of variable wettability and materials containing the fibers |
WO2008135011A2 (en) * | 2007-05-03 | 2008-11-13 | 3Mach Gmbh | Covering and sleeve |
WO2008135011A3 (en) * | 2007-05-03 | 2009-03-05 | 3Mach Gmbh | Covering and sleeve |
US20170183817A1 (en) * | 2015-12-29 | 2017-06-29 | Weyerhaeuser Nr Company | Modified fiber from shredded pulp sheets, methods, and systems |
US10156042B2 (en) * | 2015-12-29 | 2018-12-18 | International Paper Company | Modified fiber from shredded pulp sheets, methods, and systems |
US11339532B2 (en) | 2015-12-29 | 2022-05-24 | International Paper Company | Modified fiber from shredded pulp sheets, methods, and systems |
WO2021168049A1 (en) * | 2020-02-20 | 2021-08-26 | Georgia Tech Research Corporation | Treated cellulosic materials and methods of making the same |
Also Published As
Publication number | Publication date |
---|---|
TWI232744B (en) | 2005-05-21 |
ES2388031T3 (en) | 2012-10-05 |
AR029448A1 (en) | 2003-07-02 |
AR045182A2 (en) | 2005-10-19 |
EP2407135B1 (en) | 2018-06-27 |
US20030157857A1 (en) | 2003-08-21 |
PE20001307A1 (en) | 2000-12-12 |
EP1139961A4 (en) | 2009-06-03 |
EP2407135A2 (en) | 2012-01-18 |
AR045181A2 (en) | 2005-10-19 |
EP2407135A3 (en) | 2012-06-13 |
EP1139961A1 (en) | 2001-10-10 |
KR20010089673A (en) | 2001-10-08 |
WO2000038607A1 (en) | 2000-07-06 |
JP2003523484A (en) | 2003-08-05 |
CA2356651C (en) | 2007-12-04 |
ATE551978T1 (en) | 2012-04-15 |
WO2000038607A9 (en) | 2001-09-20 |
AU2384200A (en) | 2000-07-31 |
CN1354645A (en) | 2002-06-19 |
BR9917115A (en) | 2002-10-29 |
EP1139961B1 (en) | 2012-04-04 |
BR9917115B1 (en) | 2010-11-30 |
CN1281202C (en) | 2006-10-25 |
US6562743B1 (en) | 2003-05-13 |
US6770576B2 (en) | 2004-08-03 |
CA2356651A1 (en) | 2000-07-06 |
AU759840B2 (en) | 2003-05-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6562743B1 (en) | Absorbent structures of chemically treated cellulose fibers | |
EP2053999B1 (en) | Absorbent articles comprising carboxyalkyl cellulose fibers having non-permanent and temporary crosslinks | |
CA2191567C (en) | Individualized cellulosic fibers crosslinked with polyacrylic acid polymers | |
KR101508405B1 (en) | Absorbent composites having improved fluid wicking and web integrity | |
US20070270070A1 (en) | Chemically Stiffened Fibers In Sheet Form | |
EP2068948B1 (en) | Absorbent articles comprising carboxyalkyl cellulose fibers having permanent and non-permanent crosslinks | |
US20080147032A1 (en) | Methods for the preparation crosslinked carboxyalkyl cellulose fibers having non-permanent and temporary crosslinks | |
WO2004083518A2 (en) | Cross-linked fiber in sheet form and method of making | |
CA2428286A1 (en) | Crosslinked cellulose fibers | |
JP2003528989A (en) | Nonionic plasticizer for wood pulp and absorbent core | |
AU2003213513B2 (en) | Absorbent structures of chemically treated cellulose fibers | |
JP2002532639A (en) | Softened ground pulp | |
CN1951350A (en) | Absorbent structures of chemically treated cellulose fibers |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: FLEET NATIONAL BANK, MASSACHUSETTS Free format text: SECURITY INTEREST;ASSIGNOR:BKI HOLDING CORPORATION;REEL/FRAME:015365/0368 Effective date: 20041030 |
|
AS | Assignment |
Owner name: BUCKEYE TECHNOLOGIES INC., TENNESSEE Free format text: MERGER;ASSIGNOR:BKI HOLDING CORPORATION;REEL/FRAME:019550/0501 Effective date: 20070630 Owner name: BUCKEYE TECHNOLOGIES INC.,TENNESSEE Free format text: MERGER;ASSIGNOR:BKI HOLDING CORPORATION;REEL/FRAME:019550/0501 Effective date: 20070630 |
|
AS | Assignment |
Owner name: BKI HOLDING CORPORATION, DELAWARE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:COOK, JEFFERY T.;BELL, ROBERT IRVIN;FIELDS, SONJA MCNEIL;AND OTHERS;REEL/FRAME:019617/0379 Effective date: 20000204 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |