Method of manufacturing a water disintegratable non-woven fabric and the water disintegratable non-woven fabric

• US 6,451,718 B1
• Filed: 01/12/1999
• Issued: 09/17/2002
• Est. Priority Date: 01/16/1998
• Status: Expired due to Term

• Current Assignee: Unicharm Corporation
• Original Assignee: Unicharm Corporation
• Inventors: Yamada, Daisuke, Konishi, Takayoshi, Takeuchi, Naohito
• Primary Examiner(s): Morris, Terrel
• Assistant Examiner(s): Pratt, Christopher C.
• Application Number:
  US09/229,375
• Time in Patent Office: 1,344 Days
• Field of Search: 162/158, 162/101, 442/416, 442/149, 442/153, 442/165, 428/152
• US Class Current: 442/149
• CPC Class Codes: A61F 13/84 Accessories, not otherwise provided for, for absorbent pads
• CPC Class Codes: D04H 1/48 in combination with at least one other method of consolidation
• CPC Class Codes: D04H 1/49 entanglement by fluid jet in combination with another consolidation means
• CPC Class Codes: D04H 1/64 the bonding agent being applied in wet state, e.g. chemical agents in dispersions or solutions
• CPC Class Codes: D21H 17/26 Ethers thereof
• CPC Class Codes: D21H 17/36 Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
• CPC Class Codes: D21H 25/005 Mechanical treatment D21H25/08, D21H25/18 take precedence
• CPC Class Codes: Y10T 428/24446 Wrinkled, creased, crinkled or creped
• CPC Class Codes: Y10T 442/20 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
• CPC Class Codes: Y10T 442/2738 Coating or impregnation intended to function as an adhesive to solid surfaces subsequently associated therewith
• CPC Class Codes: Y10T 442/277 Coated or impregnated cellulosic fiber fabric
• CPC Class Codes: Y10T 442/2869 Coated or impregnated regenerated cellulose fiber fabric
• CPC Class Codes: Y10T 442/695 Including a wood containing layer
• CPC Class Codes: Y10T 442/698 Containing polymeric and natural strand or fiber materials

Abstract

A water disintegratable non-woven fabric having excellent water disintegratability and high wet strength can be obtained by a step of forming a fiber web from fibers having a fiber length of 10 mm or less, a step of applying a water jet treatment to the fiber web to obtain a fiber sheet having wet strength of less than 100 g/25 mm in MD and CD, the wet strength being defined by tensile strength at break of the fiber sheet, as measured by using a tensilon tester with a chuck distance of 100 mm, at a tensile speed of 100 mm/min to the fiber sheet which is cut into 25 mm width and 150 mm length and impregnated with water in an amount 2.5 times the weight of the fiber sheet, and a step of adding at least one binder selected from the group consisting of carboxymethyl cellulose, alkylcellulose, polyvinyl alcohol and modified polyvinyl alcohol to the fiber sheet. The water disintegratable non-woven fabric is sufficiently bulky and has an excellent wiping effect.

Claims

1. A water disintegratable non-woven fabric comprising:

a fiber sheet having a wet strength of less than 100 g/25 mm in a longitudinal direction and a lateral direction of the sheet; and

a binder of alkylcellulose and one of a monovalent organic and inorganic salt which is an electrolyte;

wherein the fiber sheet is prepared by subjecting a fiber web formed from fibers having a fiber length of 10 mm or less to a water jet treatment, and the binder is added to the fiber sheet after the water treatment.

2. The water disintegratable non-woven fabric as defined in claim 1, wherein the fiber sheet further comprises:

copolymers of polymerizable acid anhydride compounds; and

amino acid derivatives.

3. The water disintegratable non-woven fabric as defined in claim 2, wherein the alkylcellulose is methylcellulose, the electrolyte is sodium sulfate, the copolymer is partial sodium salt of (meth) acrylic acid (ester)-maleic acid copolymer, and the amino acid derivative is trimethyl glycine.

4. The water disintegratable non-woven fabric as defined in claim 1, wherein the sheet has a binder content of 0.5 to 30 g based on 100 g of the fibers.

5. The water disintegratable non-woven fabric as defined in claim 1, wherein without the binder the fiber sheet has a water disintegratability of 100 sec or less.

6. The water disintegratable non-woven fabric as defined in claim 1, wherein the non-woven fabric has a water disintegratability of 120 sec or less.

7. The water disintegratable non-woven fabric as defined in claim 1, wherein the fiber web has a basis weight of 20 to 100 g/m².

8. The water disintegratable non-woven fabric as defined in claim 1, wherein the fibers comprise pulp of conifer and rayon having a fiber length of 7 mm or less.

9. The water disintegratable non-woven fabric as defined in claim 8, wherein the conifer has a blending ratio of 30% or more by weight, and the rayon has a blending ratio of 70% or less by weight.

10. The water disintegratable non-woven fabric as defined in claim 1, wherein the fiber sheet has a fiber density of 0.3 g/m³ or less.

11. The water disintegratable non-woven fabric as defined in claim 1, wherein the work load of the water jet treatment per one processing is from 0.05 to 0.5 kW/m².

12. The water disintegratable non-woven fabric as defined in claim 1, wherein the electrolyte is dissolved in water, and is then impregnated in the fiber sheet.