Leak-proof Cuff Elastic Stress Distribution for Absorbent Articles

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Solution Overview

Problem

Absorbent articles with leak-proof cuffs face challenges in maintaining consistent contact with the legs of the wearer, leading to potential liquid leakage due to changes in posture and distance between the article and the legs.

Innovation Solution

The design incorporates a specific arrangement of elastic members in the leak-proof cuffs, where the stress and extension rates of the first and second regions are tailored to maintain stable contact, with the first region having a higher stress and lower extension rate than the second region, ensuring appropriate wearing pressure and preventing clearance formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastic members are provided in the leak-proof cuff to maintain contact with the wearer's legs, then liquid leakage is prevented, but excessive wearing pressure is applied to the wearer

Engineering Contradiction:
Improveleak preventionVSAvoidwearing pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent applies different elastic properties to different regions of the leak-proof cuff. The first region (outer edge) has elastic members with higher elongation stress and lower extension rate, while the second region (inner edge) has elastic members with lower elongation stress and higher extension rate. This local differentiation allows the outer region to provide strong leak prevention while the inner region reduces wearing pressure on the wearer's legs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameters of the elastic members by specifying different elongation stress ratios (σ1/σ2 between 0.8-1.2) and extension rate ratios (e1/e2 between 0.8-1.2) between regions. This parameter optimization enables the leak-proof cuff to maintain effective contact pressure for leak prevention while distributing stress to minimize excessive wearing pressure.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the leak-proof cuff is designed to rise from the diaper body to accommodate posture changes, then contact stability is improved, but the structure becomes more complex

Engineering Contradiction:
Improvecontact stabilityVSAvoidcuff structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a dynamic leak-proof cuff structure where the cuff can rise and fall relative to the diaper body in response to posture changes. The differential elastic properties between the first and second regions allow the cuff to dynamically adjust its position and contact pressure, maintaining stability without requiring complex mechanical adjustment mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent divides the leak-proof cuff into functionally distinct first and second regions with different elastic characteristics. This segmentation allows each region to perform its specific function (outer region for leak prevention, inner region for comfort and flexibility) while working together to achieve overall contact stability.

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 arrangement ensures stable contact of the leak-proof cuffs with the legs, preventing liquid leakage even with changes in posture and distance, while minimizing excessive wearing pressure on the wearer.

Implementation Method 1

at least one elastic member extending along the longitudinal direction in each of the first region and the second region

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3733140B1Absorbent article
Publication Date: 2024.08.28 KAO CORP
  • EP3733140B1 patent drawingFigure 1
  • EP3733140B1 patent drawingFigure 2
  • EP3733140B1 patent drawingFigure 3

AI summary

A leak-proof cuff (28) is divided into a lower region (40) and a upper region (41). The upper region (41) includes a first region (41A) located at the side of a free edge (28B) relative to the center in the width direction (Y) and a second region (41B) located at the side of a folding line (42). In each of the first region (41A) and the second region (41B), at least one elastic member (29) extending along the longitudinal direction (X) is provided in a stretched state. In a case where the elongation of the upper region (41) in a natural state is 0, and the elongation in a maximum stretched state is 100, the stress σ1 of the first region (41A) is larger than the stress σ2 of the second region (41B) at an elongation of 5, and the stress σ2 of the second region (41B) is larger than the stress σ1 of the first region (41A) at an elongation of 100.