Disposable Diaper Elastic Member Cutting and Graphic Sheet Integrity
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Solution Overview
Problem
In underpants-type disposable diapers, incomplete cutting of elastic members occurs when a graphic sheet is present, leading to unsatisfactory cutting and appearance issues due to reduced pressure application during the cutting process, and potential protrusion or fall-out of idle elastic members.
Innovation Solution
The method involves creating a no-extra-sheet region without the graphic sheet, where the elastic members are cut using uniform pressure, and applying a shift-preventing hot-melt adhesive to maintain precise cutting and prevent elastic member displacement, ensuring continuous cut marks from the waist to the crotch area, and welding the inner and outer sheet layers at the crotch side to prevent protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If elastic members are cut over the graphic sheet using pressure and heat, then the elastic members can be cut to prevent contraction wrinkles, but the cutting is incomplete due to reduced pressure application
Solution Approach 1:
The diaper structure is segmented into three distinct regions along the front-back direction: stretchable regions where elastic members are fixed and cut, and a non-stretchable region where the graphic sheet is disposed and elastic members are left uncut. This segmentation allows different cutting strategies to be applied to different regions, ensuring complete cutting in stretchable regions while preserving the graphic sheet appearance in the non-stretchable region.
Solution Approach 2:
Different quality requirements are applied to different parts of the elastic members based on their location. In stretchable regions, elastic members are completely cut to allow contraction. In the non-stretchable region overlapping the graphic sheet, elastic members are left uncut or partially cut to maintain the graphic appearance. This local differentiation resolves the contradiction between complete cutting and graphic sheet visibility.
2Manufacturing precision
If elastic members are completely cut in the non-stretchable region, then contraction wrinkles are prevented, but the graphic sheet appearance is compromised
Solution Approach 1:
The diaper is divided into stretchable regions and a non-stretchable region. In the non-stretchable region, elastic members are not cut, allowing the graphic sheet to remain visible and intact. In stretchable regions, elastic members are cut to enable contraction. This spatial segmentation resolves the conflict between wrinkle prevention and graphic visibility.
Solution Approach 2:
The cutting action is applied locally only to stretchable regions, while the non-stretchable region maintains its original structure with uncut elastic members and visible graphic sheet. This localized application of cutting resolves the contradiction by applying the necessary action only where it is needed without compromising the graphic appearance.
3Illumination intensity
If elastic members are not fixed to the graphic sheet, then the graphic sheet visibility is maintained, but idle elastic members may protrude or fall out
Solution Approach 1:
The diaper structure segments the handling of elastic members: in the non-stretchable region, elastic members are left uncut and unfixed to preserve graphic visibility, while in stretchable regions, elastic members are properly fixed and cut to ensure containment. This segmentation allows the graphic sheet to remain visible while idle elastic members are contained within the diaper structure through the fixed portions in stretchable regions.
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 approach ensures complete and uniform cutting of elastic members, maintains a satisfactory graphic sheet appearance, and prevents unattractive appearance and protrusion of idle elastic members by ensuring proper bonding and containment at the crotch area.
Implementation Method 1
applying a shift-preventing hot-melt adhesive to maintain precise cutting and prevent elastic member displacement
Implementation Method 2
cutting the elastic members extending over the portion to be the no-extra-sheet region by clamping an inner face of the inner sheet layer and an outer face of the outer sheet layer in the portion to be the no-extra-sheet region and applying pressure and heat
Implementation Method 3
welding the inner and outer sheet layers at the crotch side to prevent protrusion
Data Source
Figure 1
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Figure 3
AI summary
A method of producing an underpants-type disposable diaper includes forming an outer member (12) having a non-stretchable region (A1) disposed in an intermediate region in the width direction and stretchable regions (A2) disposed on the two sides of the non-stretchable region in the width direction by: fixing elastic members with a hot-melt adhesive agent (H1) to an inner sheet layer (12H) and an outer sheet layer (12S) in at least two edge portions of portions to be the stretchable regions without fixing the elastic members to the inner sheet layer nor the outer sheet layer in a portion to be the non-stretchable region; disposing a graphic sheet (25) and disposing a no-extra-sheet region (A3) between the inner sheet layer and the outer sheet layer in the side portion of the non-stretchable region, the no-extra-sheet region containing no other sheet; cutting the elastic members (15 to 17) and leaving cut marks (22) and idle elastic members (19) over the no-extra-sheet region; and leaving the elastic members in a region overlapping with the graphic sheet uncut. [Representative Drawing] Fig. 9