METHOD FOR MAKING DISPOSABLE DIAPER

• US 20100252178A1
• Filed: 01/11/2008
• Published: 10/07/2010
• Est. Priority Date: 09/05/2007
• Status: Active Grant

• Current Assignee: Unicharm Corporation
• Original Assignee: Unicharm Corporation
• Inventors: Tanji, Hiroyuki, Maeda, Yuki, Takino, Shunsuke
• Granted Patent: US 8,771,449 B2
• Time in Patent Office: Days
• US Class Current: 156/164
• CPC Class Codes: A61F 13/15593 having elastic ribbons fixed thereto; Devices for applying the ribbons
• CPC Class Codes: A61F 13/15699 Forming webs by bringing together several webs, e.g. by laminating or folding several webs, with or without additional treatment of the webs
• CPC Class Codes: A61F 13/15804 Plant, e.g. involving several steps
• CPC Class Codes: A61F 13/49011 the elastic means is located at the waist region
• CPC Class Codes: A61F 13/49017 the elastic means being located at the crotch region
• CPC Class Codes: Y10T 156/1015 Folding
• CPC Class Codes: Y10T 156/1049 Folding only

Abstract

The present invention aims to provide a method for making disposable diapers so improved that no displacement of the absorbent core from the middle between a pair of the leg elastic members. The method comprises the step P1 of bonding under tension elastic members to webs continuously fed in a machine direction MD to form front and rear sheet members the step P2 of bonding an absorbent panel provided along opposite long sides of a rectangle with a pair of elastic members for a crotch region and including an absorbent core bonded thereto so as to be symmetric about an imaginary center line bisecting a distance between a pair of the elastic members for the crotch region to the front and rear sheet members at regular intervals and the step P3 of cutting the front and rear sheet members.

Claims

1. A method for making disposable diapers comprising the steps of:

continuously feeding elastic members for a front sheet member and elastic members for a rear sheet member in parallel to each other under tension in a first machine direction and bonding these elastic members to webs of said front and rear sheet members, respectively, continuously fed in the first machine direction and thereby forming said front sheet member having a constant width dimension as measured in a direction orthogonal to the first machine direction and said rear sheet member also having a constant width dimension so that said front and rear sheet members may continuously run with a spacing from and in parallel to each other;

feeding at regular intervals an absorbent panel provided along opposite long sides with a pair of elastic members for a crotch region bonded under tension thereto and provided with an absorbent core bonded thereto so as to be symmetric about an imaginary center line bisecting a distance between said pair of elastic members for the crotch region to said front and rear sheet members running in the first machine direction, placing and bonding said absorbent panel on and to said front and rear sheet members so that said pair of elastic members for the crotch region extend orthogonally to said elastic members for the front sheet member and said elastic members for the rear sheet member; and

cutting said front and rear sheet members having said absorbent panel bonded thereto substantially along the middle between each pair of said adjacent absorbent panels to obtain individual diapers.

2. The method for making disposable diapers according to claim 1, further comprising the steps of:

continuously feeding a liquid-pervious sheet, a liquid-impervious sheet and said pair of elastic members for the crotch region in a second machine direction and feeding said absorbent core at regular intervals so as to be symmetric about said imaginary center line bisecting the distance between said pair of elastic members for the crotch region;

bonding said elastic members for the crotch region under tension to at least one of said liquid-pervious sheet and said liquid-impervious sheet and bonding said absorbent core between said liquid-pervious sheet and said liquid-impervious sheet; and

cutting said liquid-pervious sheet and said liquid-impervious sheet substantially along the middle between each pair of the adjacent absorbent cores in a direction orthogonal to said second machine direction to obtain individual said absorbent panels.

3. The method for making disposable diapers according to claim to claim 1, said step of forming the sheet members comprises the step of bonding said elastic members for the front sheet member and said elastic members for the rear sheet member under tension to said front sheet member and said rear sheet member, respectively, so that said front sheet member may contract more significantly than said rear sheet member when said elastic members for said front and rear sheet members, respectively, have tension released.

4. The method for making disposable diapers according to claim 1, said step of forming the sheet members comprises the step of adjusting a tensile stress under which said elastic members for the front sheet member are bonded to said front sheet member to be higher than a tensile stress under which said elastic members for the rear sheet member are bonded to said rear sheet member.

5. The method for making disposable diapers according to claim 1, further comprising the step of making said elastic members for the rear sheet member inelastic at least in a region of these elastic members overlapped by said absorbent core.

6. The method for making disposable diapers according to claim 1, said step of bonding comprises the step of bonding said absorbent panel to said front sheet member and said rear sheet member so that a longitudinal dimension over which said absorbent core overlaps said front sheet member is larger than a longitudinal dimension over which said absorbent core overlaps said rear sheet member.