Asymmetric Side Sheet Length for Absorbent Article Fit

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Solution Overview

Problem

Conventional pull-on absorbent articles, such as disposable diapers, often cause uneasy feelings due to leakage and discomfort around the groin and buttocks areas, with insufficient skin coverage and abnormal sensations resulting from the design of the absorbent assembly and its interaction with the wearer's body.

Innovation Solution

A pull-on absorbent article design featuring a rectangular front panel and rear panel with an absorbent assembly bridging them, including side seals and extension portions with a stretchable region that is longer on the front panel than the rear panel, providing better fit and reduced friction with the thighs while preventing leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the width of the absorbent assembly is simply enlarged to improve coverage, then the coverage area is improved, but a strange feeling or uncomfortable feeling is provided at the groin or crotch while side portions of the absorbent assembly are strongly abutted to the inner side of the thighs

Engineering Contradiction:
Improvecoverage area of absorbent assemblyVSAvoiduncomfortable feeling at groin
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The side sheet portions are configured with different properties at different locations: the front side sheet portions have greater length and are not joined to the front panel, allowing them to extend further and reduce friction; the rear side sheet portions are joined to the rear panel to provide coverage. This local differentiation allows the absorbent assembly to provide coverage without causing discomfort at the groin area.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The side sheet portions are divided into front side sheet portions and rear side sheet portions with different configurations. The front portions are longer and unjoined to reduce friction and discomfort, while the rear portions are joined to provide coverage. This segmentation allows different regions to serve different functions, resolving the contradiction between coverage and comfort.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the stretchable region is made longer to improve fit and reduce friction, then comfort is improved, but the length asymmetry between front and rear panels increases

Engineering Contradiction:
Improvecomfort during wearVSAvoidsymmetry of panels
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The side sheet portions are deliberately configured with asymmetric lengths: front side sheet portions are longer than rear side sheet portions. This asymmetry is functional, allowing the front portions to extend further to reduce friction and discomfort at the groin area, while the rear portions provide adequate coverage. The asymmetry resolves the contradiction by prioritizing comfort where it is most needed.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If side seals are added to improve leakage prevention, then leakage protection is improved, but the extension portion cannot provide sufficient coverage at the front side

Engineering Contradiction:
Improveleakage preventionVSAvoidcoverage at front side
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

Side seals are strategically positioned only in the body portion where they are needed for leakage prevention, while the extension portion remains free of side seals to provide adequate coverage and reduce friction. This local differentiation allows the design to achieve both leakage protection and sufficient front-side coverage.

Inventive Principle:
Principle #3Local quality

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 enhances comfort by minimizing strange feelings and leakage, improving the fit around the crotch area, and preventing protrusion of the buttocks, thus providing a more secure and comfortable wear.

Implementation Method 1

the side sheet portion includes a stretchable region having stretchability due to an elastic member fixed to the side sheet portion in a stretched state

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2659872B1Underwear-type absorbent article
Publication Date: 2018.03.21 KAO CORP
  • EP2659872B1 patent drawingFigure 1
  • EP2659872B1 patent drawingFigure 2~3
  • EP2659872B1 patent drawingFigure 4(a)~4(d)

AI summary

A pull-on absorbent article (1) includes a front panel (2A), a rear panel (2B), and an absorbent assembly (3) fixed to them so as to bridge them. Each of the front panel (2A) and the rear panel (2B) includes a body portion (20a, 20b) including side seals (4) at both lateral sides and an extension portion (21a, 21b) extended toward a crotch section (C). The absorbent assembly (3) includes an absorbent member (33) and side sheet portions (34) located outward of both edges in the longitudinal direction of the absorbent member (33). The side sheet portion (34) includes a stretchable region (34c) having stretchability due to an elastic member (36) fixed in a stretched state at least at the crotch section (C). In the stretchable region (34c), a length Lm from the center line (CL) of the article to a front end part (34m) is larger than a length Lu from the center line (CL) to a rear end part (34u).