Absorbent cellulosic material and production thereof

• US 5,938,894 A
• Filed: 03/24/1997
• Issued: 08/17/1999
• Est. Priority Date: 03/25/1996
• Status: Expired due to Fees

• Current Assignee: EKA Chemicals AB (Nouryon BV)
• Original Assignee: EKA Chemicals AB (Nouryon BV)
• Inventors: Lindgren, Erik, Malmborg, Kerstin, Thebrin, Ingemar, W.ang.hlen, Svante
• Primary Examiner(s): Chin, Peter
• Assistant Examiner(s): LEAVITT, STEVEN
• Application Number:
  US08/823,445
• Time in Patent Office: 876 Days
• Field of Search: 162/157.2, 162/158, 162/181.1, 162/182, 162/181.6, 162/181.7
• US Class Current: 162/181.6
• CPC Class Codes: A61L 15/18 containing inorganic materials
• CPC Class Codes: A61L 15/28 Polysaccharides or their derivatives A61L15/225 takes precedence
• CPC Class Codes: C08L 1/00 Compositions of cellulose, modified cellulose or cellulose derivatives
• CPC Class Codes: D04H 1/00 Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
• CPC Class Codes: D06M 11/74 with carbon or graphite; with carbides; with graphitic acids or their salts
• CPC Class Codes: D06M 11/79 with silicon dioxide, silicic acids or their salts
• CPC Class Codes: D06M 15/256 containing fluorine
• CPC Class Codes: D06M 2101/06 cellulosic
• CPC Class Codes: D06M 23/06 Processes in which the treating agent is dispersed in a gas, e.g. aerosols aerosol compositions C09K3/30
• CPC Class Codes: D21C 9/002 by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
• CPC Class Codes: D21H 21/22 Agents rendering paper porous, absorbent or bulky

Abstract

A method in which a sheet of cellulosic fibres is shredded into fluff wherein, prior to shredding, the fibres are treated in the presence of water with a hydrophobic substance having a specific surface area of at least about 50 m² /g, to yield improved sorptive capacity; fluff obtainable by the method; absorbent articles comprising such fluff; use of a substance of said kind for improving the sorptive capacity of absorbent material comprising the fibers; a process for production of absorbent material obtained by shredding a sheet of such fibers in which the fibers, prior to shredding, have been treated in the presence of water with a substance of said kind to yield improved sorptive capacity; and absorbent material obtainable from the process.

Claims

1. A method for production of fluff having improved take-up rate and/or liquid-retaining capacity for aqueous solutions from shredded cellulose fibers, wherein prior to shredding the cellulose fibers, the fibers are treated in the presence of water with a hydrophobic zeolite having a specific surface area of at least about 50 m² /g.

2. The method of claim 1 wherein prior to the treatment the fibres have an dry content of at least about 20%.

3. The method of claim 1 wherein the hydrophobic zeolite has a hydrophobicity of below about 0.99 percent by weight residual butanol as determined by the Residual Butanol Test.

4. The method of claim 1 wherein the fibres are sprayed or showered with a mixture comprising the substance and water.

5. The method of claim 1 wherein the fibres are suspended in an aqueous solution during the treatment, prior to forming the sheet.

6. Fluff prepared in accordance with the method of claim 1.

7. An absorbent article comprising fluff according to claim 6.

8. A method for improving the take-up rate and/or liquid-retaining capacity for aqueous solutions of an absorbant material comprising cellulose fibers obtained by shredding a sheet of such fibers which comprises treating the fibers of said absorbant material prior to shredding with a hydrophobic zeolite having a specific surface area of more than 50 m² /g.

9. The method of claim 8 wherein the hydrophobic zeolite has a hydrophobicity of below about 0.99 percent by weight residual butanol as determined by the Residual Butanol Test.

10. A process for the production of absorbent material comprising cellulosic fibers obtained by shredding a sheet of such fibers, which structure has improved take-up rate and/or liquid-retaining capacity for aqueous solutions, wherein prior to shredding said sheet, the cellulose fibers are treated in the presence of water with a hydrophobic zeolite having a specific surface area of at least 50 m² /g.

11. Absorbant material prepared in accordance with the process of claim 10.

12. Absorbant material according to claim 11 wherein the material is dry-formed nonwoven or tissue.

13. Absorbant material according to claim 11 wherein the material is fluff.