High-Density Region Sheet for Disposable Diaper Comfort
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Solution Overview
Problem
Conventional disposable diapers with elastic threads spaced 1 to 5 mm apart for adhesion and cushioning result in high rigidity, reduced skin contact sensation, and increased cost due to insufficient stretchability of nonwoven fabrics, leading to discomfort and potential autonomic imbalances.
Innovation Solution
A high-density region-containing sheet with alternating high-density and low-density regions is manufactured using shaping rolls with toothed areas, then laminated with an elastic member to create a sheet member with flexible, small irregular wrinkles, enhancing adhesion and reducing skin stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastic threads are spaced 1 to 5 mm apart in the circumferential direction to provide adhesion and cushioning, then adhesion and cushioning properties are improved, but rigidity increases and skin contact sensation is reduced
Solution Approach 1:
The patent applies local quality by creating high-density regions and low-density regions within the nonwoven fabric. The high-density regions (with fiber density of 0.03 to 0.08 g/cm³) provide structural support and adhesion, while the low-density regions (with fiber density of 0.005 to 0.02 g/cm³) provide softness and skin comfort. This local differentiation allows different areas of the same material to serve different functions, resolving the contradiction between rigidity and skin contact sensation.
Solution Approach 2:
The patent creates a composite structure within the nonwoven fabric by combining high-density and low-density regions in a single sheet member. This internal composite structure allows the material to exhibit both rigid and soft characteristics simultaneously, eliminating the need for separate elastic threads while maintaining both adhesion and skin comfort properties.
2Reliability
If nonwoven fabric with random rigidity distribution is used to form wrinkles and pleats, then cushioning properties are obtained, but adhesion is reduced and rigid feeling is increased
Solution Approach 1:
The patent replaces random rigidity distribution with a controlled local quality structure. By deliberately creating high-density regions (for cushioning and structure) and low-density regions (for flexibility and comfort) in specific patterns, the invention transforms the random rigidity distribution into an optimized local quality structure that provides cushioning without excessive rigidity or poor adhesion.
3Reliability
If elastic threads are used for body fit portion, then adhesion is improved, but weight per unit increases
Solution Approach 1:
The patent extracts the adhesion function from separate elastic threads and integrates it into the sheet member itself through the high-density regions. By taking out the need for separate elastic threading and incorporating the adhesion mechanism directly into the nonwoven fabric structure, the invention reduces overall weight while maintaining adhesion performance.
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 solution provides improved adhesion and reduced skin stimulation, resulting in a more comfortable and pleasant tactile experience while maintaining effective cushioning properties.
Implementation Method 1
compressing a sheet using shaping rolls each having a toothed area, to manufacture a high-density region-containing sheet having high-density regions and low-density regions
Implementation Method 2
a sheet member obtained by attaching the high-density regions of the high-density region-containing sheet to an elastic member
Data Source
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AI summary
A high-density region-containing sheet having a high-density region and a low-density region, a sheet member produced by joining the high-density region of the high-density region-containing sheet to an elastic member, and a disposable diaper using the sheet member as its chassis are provided. A sheet in a soft state by imparting preheat is pressed between a pair of opposed shaping rolls and having a toothed region and rotatable. Thus, a high-density region-containing sheet where high-density regions and low-density regions are formed is produced. Such two high-density region-containing sheets are joined through an extended elastic member to form a projection/recess pattern. In such a way, a high-density region-containing sheet can be produced. A sheet member in which at least one of two sheets is a high-density region-containing sheet, the high-density regions are joined through an extended elastic member, and a projection/recess pattern can be formed when the elastic member is contracted is produced.