Sanitary Napkin Embossment Segmentation for Stress Management

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Solution Overview

Problem

Existing absorbent articles with pulpless polymer sheets face issues in forming embossments with good appearance due to stress and strain accumulation during the embossing process, leading to wrinkles, breaks, and reduced functionality, as continuous embossed grooves can cause damage and inadequate fluid containment.

Innovation Solution

An absorbent article with a polymer sheet featuring superabsorbent polymer between upper and lower layers, where embossments are formed as discontinuous lines with a ratio of compressed to non-compressed parts between 7:1 and 1:1, allowing stress release and maintaining fluid containment effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If embossed grooves are formed continuously along the longitudinal direction, then fluid containment function is improved, but stress and strain accumulate causing wrinkles and breaks in the front-side sheet and absorber

Engineering Contradiction:
Improvefluid containment functionVSAvoidintegrity of front-side sheet and absorber
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The continuous embossed groove is segmented into multiple compressed parts along the longitudinal direction, separated by non-compressed parts. This segmentation allows stress and strain to be released at the non-compressed parts, preventing wrinkles and breaks while maintaining fluid containment function through the distributed compressed parts.

Inventive Principle:
Principle #1Segmentation

2Strength

If the length of non-compressed parts is short, then stress release is insufficient causing wrinkles and breaks, but if the length is too long, body fluid diffuses outward reducing absorbent article functionality

Engineering Contradiction:
Improveprevention of wrinkles and breaksVSAvoidfluid containment effectiveness
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The lengths of compressed parts and non-compressed parts are optimized within specific ranges (compressed parts: 3-70mm, non-compressed parts: 0.4-50mm) with a length ratio between 7:1 and 1:1. This parameter optimization ensures sufficient stress release at non-compressed parts while maintaining effective fluid containment through appropriately sized compressed parts.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If a pulpless polymer sheet is used as absorber, then thickness is reduced and wearing discomfort is reduced, but stress and strain from compression are less likely to be relaxed causing more wrinkles and breaks

Engineering Contradiction:
Improvethickness of absorberVSAvoidresistance to wrinkling and breaking
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The embossment is divided into compressed parts and non-compressed parts, where the non-compressed parts serve as stress release zones. This segmentation compensates for the reduced stress relaxation capability of pulpless polymer sheets, preventing wrinkles and breaks while maintaining the thin profile and comfort advantages.

Inventive Principle:
Principle #1Segmentation

4Strength

If the ratio of compressed to non-compressed part length is outside the 7:1 to 1:1 range, then stress release or fluid containment is compromised

Engineering Contradiction:
Improvestress release effectivenessVSAvoidembossment functionality
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The length ratio of compressed parts to non-compressed parts is controlled within the specific range of 7:1 to 1:1. This parameter control ensures optimal balance between stress release at non-compressed parts and fluid containment at compressed parts, maintaining both structural integrity and functional effectiveness.

Inventive Principle:
Principle #35Parameter changes

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 prevents wrinkles and breaks, maintains embossment functionality, and ensures good appearance by effectively managing stress and strain, while ensuring adequate fluid containment and wearability.

Implementation Method 1

a polymer sheet including a superabsorbent polymer disposed between an upper-layer sheet disposed on a skin side and a lower-layer sheet disposed on a non-skin side

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

prevent diffusion of body fluid in the width direction

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

an embossment that is formed on a skin-side surface of the polymer sheet along a longitudinal direction of the absorbent article and is shaped like a discontinuous line formed by arranging compressed parts and non-compressed parts alternately

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

stress and strain caused by the compression gradually accumulate... trapped stress and strain may cause the front-side sheet and the absorber to wrinkle and/or break

Methodology Applied
Scientific EffectStress relaxation: Stress Relaxation

Data Source

PatentEP3677234B1Absorbent article
Publication Date: 2022.10.05 DAIO PAPER CORP
  • EP3677234B1 patent drawingFigure 1
  • EP3677234B1 patent drawingFigure 2~3
  • EP3677234B1 patent drawingFigure 4

AI summary

This disclosure makes it possible to form embossments with good appearance even when a polymer sheet is used as an absorber and makes it possible to reliably implement the function of the embossments. A sanitary napkin (1) includes a polymer sheet (4) including a superabsorbent polymer (12) disposed between an upper-layer sheet (10) disposed on a skin side and a lower-layer sheet (11) disposed on a non-skin side, and an embossment (20) that is formed on a skin-side surface of the polymer sheet (4) along a longitudinal direction of the sanitary napkin (1) and is shaped like a discontinuous line formed by arranging compressed parts (21) and non-compressed parts (22) alternately. The ratio A:B of a length (A) of each of the compressed parts (21) to a length (B) of each of the non-compressed parts (22) is between 7:1 and 1:1.