Sanitary napkin having a low stiffness region and incisions

• US 7,857,797 B2
• Filed: 08/16/2005
• Issued: 12/28/2010
• Est. Priority Date: 09/14/2004
• Status: Active Grant

• Current Assignee: Unicharm Corporation
• Original Assignee: Unicharm Corporation
• Inventors: Miyama, Takuya, Kudo, Jun
• Primary Examiner(s): Zalukaeva; Tatyana
• Assistant Examiner(s): Chapman; Ginger T
• Application Number:
  US11/206,008
• Publication Number:
  US 20060058761A1
• Time in Patent Office: 1,960 Days
• Field of Search: 604/383, 604/385.01, 604/358, 604/378, 604/380, 604/385.16, 604/385.23
• US Class Current: 604/385.01
• CPC Class Codes: A61F 13/4704 having preferential bending zones, e.g. fold lines or grooves
• 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

Abstract

Disclosed is a sanitary napkin including a liquid absorbent layer and a liquid-permeable topsheet covering a body surface of the liquid absorbent layer. The topsheet is joined to the liquid absorbent layer in a specific pattern. The pattern includes longitudinal join lines which extend longitudinally and are laterally spaced from each other and a connecting join line which connects the longitudinal join lines. The liquid absorbent layer has a low stiffness portion in a region enclosed by the longitudinal join lines and the connecting join line. The liquid absorbent layer has a lower stiffness in the low stiffness portion than in portions outside the longitudinal join lines.

Claims

1. A sanitary napkin comprising:

a liquid absorbent layer and a liquid-permeable topsheet covering a body surface of the liquid absorbent layer, the topsheet being joined to the liquid absorbent layer in a specific pattern;

wherein the pattern includes longitudinal join lines which extend longitudinally and are laterally spaced from each other and connecting join lines which connect the longitudinal join lines to define a continuous border defining an elongated enclosed region, and wherein the liquid absorbent layer has a thickness of 1.5 to 5 mm, and

wherein said enclosed region of the absorbent layer comprises a plurality of incisions through the absorbent layer, and wherein said plurality of incisions are configured so that the portion of the absorbent layer inside the enclosed region has a lower stiffness than the portion of the absorbent layer outside the enclosed region.

2. The sanitary napkin of claim 1, wherein the liquid absorbent layer is an air-laid pulp made of pulp fibers, the pulp fibers being deposited by an air-laid process, pressed, and bonded together through a binder between the pulp fibers.

3. The sanitary napkin of claim 2, wherein the liquid absorbent layer is an air-laid nonwoven fabric made of pulp fibers and thermoplastic synthetic resin fibers, the pulp fibers and the thermoplastic synthetic resin fibers being deposited by an air-laid process, pressed, and bonded together through a binder between the fibers.

4. The sanitary napkin of claim 1, wherein the liquid absorbent layer is an air-laid nonwoven fabric made of pulp fibers and thermoplastic synthetic resin fibers, the pulp fibers and the thermoplastic synthetic resin fibers being deposited by an air-laid process, heated under pressure, and bonded together by fusion of the thermoplastic synthetic fibers.

5. The sanitary napkin of claim 1, wherein the liquid absorbent layer is an air-laid pulp.

6. The sanitary napkin of claim 1, wherein the liquid absorbent layer is formed by compressing a fiber deposition including pulp fibers.

7. The sanitary napkin of claim 1, wherein each incision crosses another incision at a right angle.

8. The sanitary napkin of claim 7, wherein each paired incision is inclined at an angle of 45°

from the centerline of the sanitary napkin.

9. The sanitary napkin of claim 1, wherein said liquid absorbent layer has a density ranging from 0.05 to 0.2 g/cm³.

10. A sanitary napkin comprising:

a liquid absorbent layer having a top surface and a bottom surface; and

a liquid-permeable topsheet covering a body surface of the liquid absorbent layer, wherein the topsheet is joined to the liquid absorbent layer in a specific pattern including;

longitudinal join lines which extend longitudinally from a centerline of the sanitary napkin and are laterally spaced from each other each between the centerline and an edge of the liquid absorbent layer, and

connecting join lines which connect the longitudinal join lines to define a continuous border defining an elongated enclosed region,

wherein;

the liquid absorbent layer (i) has a plurality of incisions covered by the topsheet, which pass through from the top surface of the absorbent layer to the bottom surface of the absorbent layer, thereby providing a low stiffness portion in the elongated enclosed region, the liquid absorbent layer having a lower stiffness in the low stiffness portion than in portions outside the longitudinal join lines,

(ii) has a plurality of incisions regularly arranged in pairs in which each incision crosses another and each of the plurality of incisions pierces the liquid absorbent layer, the plurality of incisions being confined to and distributed over the elongated enclosed region, (iii) comprises fibers pressed into a sheet and bonded together with a binder or through fusion of said fibers, (iv) has a thickness ranging from 0.5 to 5 mm, and (v) has a unit weight ranging from 70 to 300 g/m².

11. The sanitary napkin of claim 10, wherein said liquid absorbent layer has a density ranging from 0.05 to 0.2 g/cm³.

12. A sanitary napkin comprising:

a liquid absorbent layer having a top surface and a bottom surface; and

a liquid-permeable topsheet covering a body surface of the liquid absorbent layer, wherein the topsheet is joined to the liquid absorbent layer along a continuous join line defining an elongated enclosed region, said continuous join line comprising;

longitudinal join lines which extend longitudinally from a centerline of the sanitary napkin and are laterally spaced from each other each between the centerline and an edge of the liquid absorbent layer,

front and rear connecting join lines which are respectively positioned between a lateral center line of the sanitary napkin and front and rear edges of the sanitary napkin, the front and rear connecting join lines extending laterally to connect the longitudinal join lines, wherein said topsheet is also joined to said liquid absorbent layer along

front and rear internal connecting join lines which are respectively positioned between the lateral center line and the front and rear connecting join lines,

wherein;

the liquid absorbent layer (i) has a first low stiffness portion in a first area delimited by the longitudinal join lines, the front connecting join line and the front internal connecting join line,

(ii) has a second low stiffness portion in a second area delimited by the longitudinal join lines, the rear connecting join line and the rear internal connecting join line,

(iii) has a lower stiffness in each of the first and second low stiffness portions than in portions of the liquid absorbent layer outside of the first and second areas,

(iv) has a plurality of incisions covered by the topsheet, which pass through from the top surface of the absorbent layer to the bottom surface of the absorbent layer, and regularly arranged in pairs in which the paired incisions cross one another and each of the plurality of incisions pierces the liquid absorbent layer, (v) comprises fibers pressed into a sheet and bonded together with a binder or through fusion of said fibers, (vi) has a thickness ranging from 0.5 to 5 mm, and (vii) has a unit weight ranging from 70 to 300 g/m², and

the plurality of incisions are confined to and distributed over the first and second areas.

13. The sanitary napkin of claim 12, wherein said liquid absorbent layer has a density ranging from 0.05 to 0.2 g/cm³.