Elastic Sheet Weld Layout to Prevent Elastic Member Slip-Off
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Solution Overview
Problem
Stretchable sheets in underpants-shaped absorbent articles, such as disposable diapers, face issues with deteriorating stretchability due to elastic members falling off from welded portions when stretched, leading to reduced effectiveness.
Innovation Solution
A stretchable sheet design featuring elastic members sandwiched between two sheets with welded portions on both sides, where the elastic members have damaged portions that are caught by adjacent welded pairs, preventing displacement and maintaining stretchability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If elastic members are clamped between welded portion pairs to fix them without adhesive, then manufacturing is simplified and adhesive is eliminated, but stretchability deteriorates when elastic members fall off from between welded portions during stretching
Solution Approach 1:
The elastic member is pre-damaged (cut or notched) before being sandwiched between the welded portions. This preliminary action creates an expanded state that increases the outer diameter, ensuring the damaged portion will be caught by the welded portions during subsequent stretching, preventing the elastic member from falling off and maintaining stretchability throughout the product lifecycle
Solution Approach 2:
The damage to the elastic member creates a counteracting force through expansion. When the elastic member is stretched, the damaged portion expands and is caught by the welded portions, creating a mechanical interlock that prevents displacement. This preliminary anti-action counteracts the tendency of the elastic member to slide out during use
2Ease of operation
If elastic members are stretched and contracted repeatedly, then stretchability is utilized, but elastic members may fall off from between welded portions causing stretchability deterioration
Solution Approach 1:
The outer diameter parameter of the elastic member is changed through damage (cutting or notching). This parameter change creates an expanded state that allows the damaged portion to be caught by the welded portions during stretching, ensuring the elastic member remains securely positioned while maintaining its stretchability function throughout repeated use
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
The design ensures that elastic members remain firmly attached, reducing the likelihood of stretchability deterioration and preventing elastic members from coming off, thereby maintaining consistent performance.
Implementation Method 1
a first sheet (32); a second sheet (33) that is joined to the first sheet (32) by a plurality of welded portions (50)
Implementation Method 2
an elastic member (35) that is provided between the first sheet (32) and the second sheet (33), the elastic member (35) being capable of stretching and contracting in a continuous direction
Data Source
Figure 1
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Figure 3
AI summary
A elastic sheet (31) having a first sheet (32), a second sheet (33) joined in a plurality of welds (50) with the first sheet (32), and an elastic member (35) provided between the first sheet (32) and the second sheet (33), the elastic member (35) being capable of expanding and contracting in a continuous direction, the plurality of welds (50) being positioned on both sides of the elastic member (35) in an intersecting direction, and the elastic sheet (31) having weld pairs (50s) in which the elastic member (35) is interposed, wherein the elastic member (35) has a damaged section (37) in which a portion of the surface thereof is damaged, the weld pairs (50s) have a first weld pair (51s) and a second weld pair (52s) which is disposed adjacent to the first weld pair (51s) in the continuous direction, and at least one damaged section (37) is provided between the first weld pair (51s) and the second weld pair (52s) in the continuous direction.