Variable Stretch Rate Elastic Film for Absorbent Article Waist
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Solution Overview
Problem
Conventional absorbent articles with elastic film stretchable regions face challenges in varying elasticity based on the part, leading to difficulties in forming continuous stretchable regions due to width-decreasing issues during production, and require additional rubber threads for enhanced waist portion contraction.
Innovation Solution
An absorbent article with a stretchable region formed by interposing an elastic film between nonwoven fabric sheet layers, where the elastic film is stretched at a continuously changing rate orthogonal to the stretching direction, allowing for adjustable elasticity and improved fitness by altering the interval between bond portions and through holes, eliminating the need for separate rubber threads at the waist portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple elastic films with different stretch rates are fixed to change elasticity by part, then elasticity can be varied depending on the part, but width-decreasing occurs during tension application and continuous stretchable region formation becomes difficult
Solution Approach 1:
The patent applies parameter changes by varying the stretch rate continuously across the width of a single elastic film. Specifically, the stretch rate increases from the crotch side toward the waist opening side, creating different elasticity levels in different regions without using multiple separate elastic films. This resolves the contradiction by achieving part-specific elasticity variation while maintaining continuous stretchable region formation.
2Ease of manufacture
If elastic film is stretched at uniform rate, then manufacturing is simple, but elasticity cannot be changed depending on the part
Solution Approach 1:
The patent implements parameter changes by applying a non-uniform stretch rate to the elastic film during manufacturing. The stretch rate continuously increases from the crotch side to the waist opening side, allowing different regions of the same elastic film to exhibit different elasticity characteristics. This maintains manufacturing simplicity while achieving part-specific elasticity adaptation.
3Force
If separate rubber threads are added to waist portion, then contraction force is enhanced, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating region-specific elasticity within a single elastic film through variable stretch rates. The waist region, which requires higher contraction force, is achieved by applying a higher stretch rate to that specific area during manufacturing. This eliminates the need for separate rubber threads while maintaining the required contraction force, thereby reducing structural complexity.
Solution Approach 2:
The patent makes the single elastic film multi-functional by enabling it to provide both the stretchable structure and the part-specific contraction forces that would traditionally require separate components. The elastic film simultaneously serves as the base structure and the source of varied elasticity, replacing the need for additional rubber threads and simplifying the overall device structure.
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 enables adjustable elasticity across different parts of the absorbent article, enhancing fitness and air permeability while maintaining a consistent appearance by distributing contraction forces effectively without additional rubber threads, thus improving the overall performance and design of the absorbent article.
Implementation Method 1
the elastic film is stretched in a stretching and contracting direction of the stretchable region at a stretch rate continuously changing in a direction orthogonal to the stretching and contracting direction
Data Source
Figure 1
Figure 2
Figure 3(a)~3(d)
AI summary
Provided are an absorbent article having an elastic film stretchable region in which a stretch rate changes depending on the part, and a method of manufacturing the same. The above problem is solved when a stretchable region (80) being stretchable at least in a width direction is included in a lower-torso region (T) having a waist portion (23) of an outer body (20) of a front body (F) and an outer body (20) of a back body (B), and in the stretchable region (80), in a state in which an elastic film (30) is stretched in a stretching and contracting direction at a stretch rate continuously increasing from a crotch side toward a waist opening side, a first sheet layer (20A) and a second sheet layer (20B) are joined.