Elastic Sheet Welding for Diaper Stretchability
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Solution Overview
Problem
Stretchable sheets in underpants-shaped absorbent articles, such as diapers, face issues with deteriorating stretchability due to elastic members falling off from welded portions when stretched, leading to reduced fit and comfort.
Innovation Solution
A stretchable sheet design where elastic members are sandwiched between two sheets with welded portions on both sides, incorporating damaged portions to secure the elastic members, preventing displacement and detachment, thereby maintaining stretchability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If elastic members are clamped between welded portion pair without adhesive, then manufacturing is simplified and adhesive usage is eliminated, but elastic members may fall off when stretched causing stretchability deterioration
Solution Approach 1:
The patent applies preliminary action by forming protrusions on the elastic members before clamping them between the welded portions. These protrusions are created in advance during the elastic member manufacturing process, enabling the elastic members to be securely retained without adhesive while maintaining stretchability. This preliminary structural modification prevents the harmful effect of elastic members falling off during stretching.
2Ease of manufacture
If welded portion pair is formed to clamp elastic members, then adhesive is not needed for fixation, but the structure becomes complex requiring precise welding positioning
Solution Approach 1:
The patent applies local quality by concentrating the retention function at specific locations on the elastic members - the protrusions. Instead of requiring complex welded portion structures throughout, the localized protrusions provide the necessary retention function at key points, simplifying the overall welded portion design while maintaining secure elastic member fixation without adhesive.
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 effectively prevents elastic members from detaching from welded portions, ensuring consistent stretchability and improved fit by securely attaching the elastic members to the sheets.
Implementation Method 1
an elastic member (35, 45) that is capable of stretching and contracting in a continuous direction
Implementation Method 2
the elastic member (35, 45) having a damaged portion (37) where a part of a surface of the elastic member (35, 45) is damaged
Data Source
Figure 1
Figure 2
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.