Pull-on Diaper Side Seal Welding Integrity
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Solution Overview
Problem
Existing methods for manufacturing pull-on diapers face challenges in ensuring sufficient welding strength at the side parts due to damage from cutting tools, which can lead to inadequate heat-welding strength at damaged areas.
Innovation Solution
A method involving the continuous manufacturing of pull-on absorbent articles where elastic members are stretched and cut between adhesion areas, allowing contraction and shifting relative to exterior members, with welding sections formed after contraction and before cutting, ensuring the welded sections do not overlap adhesion areas for improved strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If elastic members are divided in advance before heat-sealing and cutting processes, then the sealed area can prevent contraction and maintain good appearance, but the continuous sheet is likely to be damaged by cutting tools
Solution Approach 1:
The patent applies preliminary action by forming adhesion areas with adhesive on the continuous sheet before the elastic members are cut. This ensures that when elastic members are subsequently divided, the adhesion areas are already in place to prevent contraction, and the cutting tools do not damage the sheet because the adhesive provides preliminary bonding strength. The adhesive application occurs at positions that will become the adhesion areas after elastic member division, allowing the sheet to maintain integrity throughout the cutting process.
2Productivity
If cutting tools are used to divide elastic members, then the elastic members can be separated, but the continuous sheet may be damaged leading to insufficient welding strength
Solution Approach 1:
The patent uses adhesive as an intermediary substance applied to the continuous sheet at adhesion areas. This adhesive layer acts as a mediator that protects the continuous sheet from damage by cutting tools during the elastic member division process. The adhesive provides bonding strength that prevents the sheet from being cut or damaged, while still allowing the elastic members to be divided. This intermediary adhesive layer ensures both continuous manufacturing efficiency and integrity of the continuous sheet.
3Device complexity
If welding sections overlap adhesion areas, then the manufacturing process is simplified, but the welding strength is compromised due to potential damage from cutting tools
Solution Approach 1:
The patent applies segmentation by dividing the side sealing area into distinct functional zones: adhesion areas where adhesive is applied to prevent elastic member contraction, and welding sections where heat-sealing is performed. These zones are positioned such that the welding sections do not overlap with the adhesion areas. This segmentation ensures that the adhesive's preventive function and the welding's bonding function are both optimized, with the welding sections located where the continuous sheet has not been exposed to cutting tools and maintains full strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances the welding strength of the side parts of pull-on diapers by preventing damage during cutting and ensuring that the welding sections are formed in a way that maintains the integrity of the adhesive areas, thus improving the overall appearance and functionality of the diapers.
Implementation Method 1
an adhesion area is formed by putting adhesive on each side of the cutting position in the transport direction, of at least either one of the lower bandlike member and the upper bandlike member
Implementation Method 2
at least some of the plurality of elastic members that are stretched in the transport direction contract in the transport direction towards the adhesion area from positions at which the at least some of the plurality of elastic members are cut
Implementation Method 3
a welded section on which the folded lower bandlike member and the folded upper bandlike member are to be welded to each other is formed
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A method for manufacturing an absorbent article, including: while lower bandlike member (15) is transported in a transport direction, a process in which a cutting position (CL) is determined, and an adhesion area (HMA) is formed by putting adhesive on each side of the cutting position (CL) of the lower bandlike member (15) in the transport direction; a process in which a plurality of elastic members (8B, 8F, 8L) are placed so that a part of each the elastic members (8B, 8F, 8L) overlaps the adhesion area (HMA), the elastic members (8B, 8F, 8L) being stretched in the transport direction; a process in which an upper bandlike member (17) is stacked on the lower bandlike member (15) and the elastic members (8B, 8F, 8L), and the upper bandlike member (17) adheres to the lower bandlike member (15) and the elastic members (8B, 8F, 8L) on the adhesion area (HMA); a process in which the lower bandlike member (15) and the upper bandlike member (17) are folded on a center position in an intersecting direction; a process in which the elastic members (8B, 8F, 8L) are cut at a single position between a pair of the adhesion areas (HMA) which are respectively formed on both sides of the cutting position (CL), and the elastic members (8B, 8F, 8L) contract towards the adhesion area (HMA) from positions at which the elastic members (8B, 8F, 8L) are cut; a process in which a welded section (s1) on which the lower bandlike member (15) and the upper bandlike member (17) are to be welded to each other is formed on each side of the cutting position (CL) in the transport direction; and a process in which the lower bandlike member (15) and the upper bandlike member (17) are cut together on the cutting position (CL).