Highly water absorbent sheet

• US 6,790,798 B1
• Filed: 09/22/2000
• Issued: 09/14/2004
• Est. Priority Date: 09/29/1999
• Status: Expired due to Term

• Current Assignee: The Procter & Gamble Company, DSG International Limited (Unicharm Corporation)
• Original Assignee: Absorbent Technology Institute
• Inventors: Suzuki, Migaku, Matsumoto, Ryoichi
• Primary Examiner(s): Sperty, Arden B
• Application Number:
  US09/667,815
• Time in Patent Office: 1,453 Days
• Field of Search: 442/373, 442/374, 608/378, 608/385.01
• US Class Current: 442/374
• CPC Class Codes: A61F 13/15658 Forming continuous, e.g. composite, fibrous webs, e.g. involving the application of pulverulent material on parts thereof
• CPC Class Codes: A61F 13/5323 having absorbent material located in discrete regions, e.g. pockets
• CPC Class Codes: A61F 13/534 having an inhomogeneous composition through the thickness of the pad A61F13/538, A61F13/539 take precedence; homogeneous cores with tissue wrapping A61F13/53
• CPC Class Codes: A61F 13/535 inhomogeneous in the plane of the pad, e.g. core absorbent layers being of different sizes A61F13/5323, A61F13/537 take precedence
• CPC Class Codes: A61F 2013/15016 for breast; pads for bras
• CPC Class Codes: A61F 2013/53051 being only in particular parts or specially arranged
• CPC Class Codes: A61F 2013/530532 the maximum being at certain depth in the thickness
• CPC Class Codes: A61F 2013/530562 being arranged in discontinuous pattern
• CPC Class Codes: Y10T 442/651 Plural fabric layers
• CPC Class Codes: Y10T 442/652 Nonwoven fabric is coated, impregnated, or autogenously bonded

Abstract

A highly absorbent composite sheet wherein a non-woven substrate having a bulky structure and solid SAP with a part contained inside said bulky structure and the rest exposed on the surface of said non-woven substrate are provided, a thermally fusible component being a hot-melt adhesive, the hot-melt adhesive forming a fibrous network and covering said solid SAP and fine cellulose fibers in contact with the solid SAP whereby a single or double fibrous network is provided with the solid SAP held in position. A method for manufacturing same, and an absorbent article using such highly absorbent composite sheet are also provided.

Claims

1. Highly absorbent composite sheet comprising:

a non-woven fabric substrate having a bulky structure;

solid SAP partly contained inside said bulky structure and partly disposed on a surface of said non-woven substrate; and

a fibrous network in a form of a mesh formed of a hot-melt adhesive as a thermally fusible component, said fibrous network contacting and covering said solid SAP to trap and hold the solid SAP so that said solid SAP is held in position.

2. The highly absorbent composite sheet of claim 1, further comprising fine cellulose disposed on the solid SAP as a layer, said fine cellulose being covered by the fibrous network.

3. The highly absorbent composite sheet of claim 1, wherein a coated amount of said hot-melt adhesive is 0.2 to 10 g/m².

4. The highly absorbent composite sheet of claim 1, wherein said hot-melt adhesive is mainly composed of ethylene-vinyl acetate copolymer and non-tacking.

5. The highly absorbent composite sheet of claim 4, wherein a content of vinyl acetate in ethylene-vinyl acetate which is a main composition of said hot-melt adhesive is 20 to 40% by weight and a thermal fluidity rate of said hot-melt adhesive is 50 to 150 g/10 minutes.

6. A highly absorbent composite comprising:

a composite absorbent including a non-woven substrate, a SAP layer, and a fibrous network in a form of a mesh formed of a hot-melt adhesive layer as a thermally fusible component, said fibrous network contacting and substantially entirely covering said SAP layer to trap and hold the SAP layer, and

a sheet material disposed on said adhesive layer and bonded with said composite absorbent by said hot-melt adhesive layer by an adhesive property thereof to form a composite structure.

7. A highly absorbent composite comprising:

first and second composite absorbents, each comprising a non-woven substrate, an SAP layer, and a fibrous network in a form of a mesh formed of a hot-melt adhesive layer as a thermally fusible component, said fibrous network contacting and covering said SAP layer to trap and hold the SAP layer, said first composite absorbent being laid on the second composite absorbent such that said hot-melt adhesive layers contact with each other and are bonded together by an adhesive property thereof to form a two material composite structure.

8. The highly absorbent composite of claim 7, further comprising an additional sheet material interposed between said first and second composite absorbents and bonded thereto by the adhesive property of said hot-melt layers of said first and second composite absorbents to form a three material composite structure.

9. A highly absorbent composite sheet comprising:

a non-woven substrate including a non-woven fabric with voids therein,

solid SAP partly disposed in the voids and distributed almost all over in a layer on a surface of the non-woven fabric, and

a dual fibrous network contacting and covering a surface of the solid SAP to trap and hold the solid SAP, said dual fibrous network having a first fibrous network in a form of dense mesh comprising a hot-melt adhesive as a thermally fusible component and a second fibrous network in a form of loose mesh coarser than the dense mesh and positioned over said first fibrous network.

10. The highly absorbent composite sheet of claim 9, wherein said dual fibrous network substantially entirely covers the solid SAP to thereby prevent the solid SAP from coming off.

11. The highly absorbent composite sheet of claim 9, wherein the fibers of said hot-melt layer of dense mesh are finer than the fibers of said hot-melt layer of loose mesh.