Method for making a liquid absorbent pad

• US 5,662,634 A
• Filed: 04/23/1996
• Issued: 09/02/1997
• Est. Priority Date: 06/08/1995
• Status: Expired due to Term

• Current Assignee: Unicharm Corporation
• Original Assignee: Unicharm Corporation
• Inventors: Ono, Yoshio, Fujioka, Yoshihisa, Yamamoto, Masamitsu
• Primary Examiner(s): Weiss, John G.
• Assistant Examiner(s): O YONG, KI
• Application Number:
  US08/637,943
• Time in Patent Office: 497 Days
• Field of Search: 604/378, 604/380, 604/379, 604/383, 604/385.1, 604/385.2, 428/182, 428/186, 428/169, 428/170, 428/161, 156/257, 156/229, 156/238, 156/230, 156/244.11, 156/244.25
• US Class Current: 604/378
• CPC Class Codes: A61F 13/5323 having absorbent material located in discrete regions, e.g. pockets
• CPC Class Codes: A61F 13/533 having discontinuous areas of compression
• CPC Class Codes: A61F 13/53436 having an undulated or corrugated cross-section
• CPC Class Codes: Y10T 428/24694 Parallel corrugations

Abstract

A liquid absorbent pad includes an elastically stretchable basic sheet upon which an absorbent core is periodically bonded. The absorbent core is bonded while the basic sheet is stretched. The absorbent core includes a structure which encourages the formation of corrugations therein when the basic sheet is released. The corrugations enable the flow of material in the troughs of the corrugations, and thereby reduce soilage of the upper surface of the absorbent core by fecal matter. The liquid absorbent pad is suitable for undergarment use in which the basic sheet includes a waist opening and a pair of leg openings. In one embodiment, the structure which encourages the formation of corrugations includes gaps between adjacent strips of absorbent material. In another embodiment, the structure is periodic regions of reduced density or rigidity. In a further embodiment, the structure includes periodic longitudinal indentations alternating on opposite sides of the absorbent pad.

Claims

1. A method for making a liquid absorbent pad comprising the steps of:

applying a tension for stretching a first substantially planar element along an axis;

forming first and second alternating linear parallel portions in a second substantially planar element, at least one of said first and second linear portions including an absorbent material;

said first alternating linear parallel portion having at least one of reduced rigidity and increased flexibility compared to said second alternating linear parallel portion;

periodically affixing said second substantially planar element to said first substantially planar element along a plurality of lines generally parallel to said first and said second alternating linear parallel portions, and perpendicular to the direction of said tension; and

releasing said tension, whereby said second substantially planar element is corrugated along said parallel portions.

2. The method according to claim 1, wherein said second linear parallel portion has a higher density than said first linear parallel portion.

3. The method according to claim 2, wherein said second linear parallel portion includes said absorbent material.

4. The method according to claim 3, wherein:

said first and said second linear parallel portions include absorbent material; and

said second linear parallel portion has a higher density than said first linear parallel portion.

5. The method according to claim 1, wherein:

said step of forming said second alternating linear parallel portion in said second substantially planar element includes forming a plurality of spaced-apart parallel portions of said absorbent material; and

said step of forming said first alternating linear parallel portion in said second substantially planar element includes providing gaps between said second linear portion, whereby said first linear portion has said one of reduced rigidity and increased flexibility.

6. The method according to claim 2, wherein said second substantially planar element is affixed to said first substantially planar element at at least one point in a vicinity of a midpoint between adjacent said first linear parallel portions.

7. A method for making a liquid absorbent pad comprising the steps of:

applying a tension for stretching a first substantially planar element along an axis;

forming a first and second alternating linear parallel portions in a second substantially planar element, said second substantially planar element comprising an absorbent material;

said first alternating linear parallel portions having one of reduced rigidity and increased flexibility compared to said second alternating linear parallel portion;

said step of forming said first and said second alternating linear parallel portions includes compressing parallel grooves alternating on opposite sides of said second substantially planar element;

periodically affixing said second substantially planar element to said first substantially planar element along a plurality of lines generally parallel to said grooves, and perpendicular to the direction of said tension; and

releasing said tension, whereby said second substantially planar element is corrugated along said parallel grooves.

8. The method according to claim 7, wherein said second substantially planar element is affixed to said first substantially planar element at at least one point in a vicinity of a midpoint between adjacent said parallel grooves.