Absorbent Article Elastic Film Segmentation

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Solution Overview

Problem

Absorbent articles using elastic films face limitations in maximum elongation and tensile strength, leading to reduced stretchability and impaired softness due to the arrangement and size of joining-opening sections, which affect extension stress and air permeability.

Innovation Solution

The absorbent article features a laminated structure with a stretchable region composed of a first and second non-stretchable sheet layered with an elastic film, where the joining-opening sections are formed by welding the sheets with specific dimensions and patterns, including adjacent sections arranged in inclined directions to optimize elongation and tensile strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the elastic film is joined to non-stretchable sheets through joining-opening sections, then the absorbent article gains elasticity and stretchability, but the tensile strength and maximum elongation are limited

Engineering Contradiction:
ImprovestretchabilityVSAvoidtensile strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The elastic film is divided into multiple sections by creating joining-opening sections at intervals. These sections are joined to non-stretchable sheets through openings, creating a segmented structure that allows the elastic film to stretch between joining points while maintaining strength at the joining sections. This segmentation enables both stretchability and tensile strength to coexist.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the elastic sheet have different properties: the joining-opening sections provide strength and stability, while the regions between joining sections provide elasticity and stretchability. This local differentiation allows the material to simultaneously exhibit both tensile strength and stretchability in different locations.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the joining-opening sections are arranged in a regular pattern, then the manufacturing process is simplified, but the air permeability and softness are reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidair permeability
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The joining-opening sections are arranged in an asymmetric, irregular pattern rather than a regular grid. This asymmetric arrangement creates varied opening sizes and spacing that improve air permeability and prevent the formation of continuous wrinkles, while still maintaining manufacturability through a systematic but non-uniform distribution pattern.

Inventive Principle:
Principle #4Asymmetry

3Adaptability or versatility

If the elastic film is stretched to increase maximum elongation, then stretchability improves, but extension stress increases and softness is impaired

Engineering Contradiction:
Improvemaximum elongationVSAvoidextension stress
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

By segmenting the elastic film into multiple joining sections, the stress is distributed across multiple joining points rather than concentrating at a single location. This allows the film to be stretched to higher elongation levels while the extension stress is managed through the distributed joining structure, preventing excessive stress accumulation that would impair softness.

Inventive Principle:
Principle #1Segmentation

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 configuration reduces extension stress, enhances air permeability, and increases maximum elongation while maintaining softness by preventing continuous wrinkles, thus improving the overall performance of the absorbent article.

Implementation Method 1

an elastic film 23 elongated in a left-right direction is layered between a first nonwoven fabric 21 and a second nonwoven fabric 22, heat sealing or ultrasonic sealing is performed in a number of dot-like patterns or linear patterns, and each layer of the layered sheet is joined. When each layer of the layered sheet is joined, the periphery of joining portions (sealed portions) of the elastic film is broken to form opening portions (through holes)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

heat sealing or ultrasonic sealing is performed in a number of dot-like patterns or linear patterns, and each layer of the layered sheet is joined

Methodology Applied
Scientific EffectHeat sealing:

Implementation Method 3

heat sealing or ultrasonic sealing is performed in a number of dot-like patterns or linear patterns, and each layer of the layered sheet is joined

Methodology Applied
Scientific EffectUltrasonic sealing: Ultrasonic Vibration

Data Source

PatentEP3459512B1Absorbent article
Publication Date: 2023.04.12 KOYO CORP
  • EP3459512B1 patent drawingFigure 1
  • EP3459512B1 patent drawingFigure 2
  • EP3459512B1 patent drawingFigure 3

AI summary

The present invention reduces the extension stress of an absorbent article to make it easy to stretch, improves the air permeability, and increase the maximum elongation. Provided is an absorbent article (1) comprising a stretchable region, wherein the stretchable region of the absorbent article (1) is made of an elastic sheet in which a first non-stretchable sheet (21), an elastic film (23) and a second non-stretchable sheet (22) are laminated in this order. The elastic sheet is provided with a plurality of joining-opening sections (51-55) that are constituted by joints (51a-55a) to join the first non-stretchable sheet (21) and the second non-stretchable sheet (22) and openings (51b-55b) to be generated in the elastic film (23) by forming the joints (51a-55a). The joints (51a-55a) are formed by joining the first non-stretchable sheet (21) and the second non-stretchable sheet (22) in a state where the elastic film (23) is extended in a stretchable direction of the elastic region. Some or all of the joining-opening sections (51-55) form adjacent joining-opening sections (50A, 50B) constituted by a plurality of the joining-opening sections (51-55) which are close to each other.