Absorbent Article Cellulose Nanofiber Layer Moisture Management

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Solution Overview

Problem

Conventional absorbent articles with high moisture perviousness in the liquid impervious resin film cause a moist feel on the product outer surface or underwear, leading to false perceptions of leakage, while reducing moisture perviousness compromises stuffiness prevention.

Innovation Solution

Incorporating a cellulose nanofiber layer between the liquid impervious resin film and the exterior nonwoven fabric, which allows moisture to be retained without blocking it, maintaining stuffiness prevention and preventing a moist feel on the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the liquid impervious resin film has high moisture perviousness to prevent stuffiness, then air permeability and comfort are improved, but the product outer surface retains moisture and imparts a moist feel

Engineering Contradiction:
Improvestuffiness preventionVSAvoidmoist feel on product outer surface
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A cellulose nanofiber layer is introduced as an intermediary between the liquid impervious resin film and the exterior nonwoven fabric. This intermediate layer absorbs and retains moisture that passes through the resin film, preventing it from reaching the product outer surface while still allowing air permeability to maintain stuffiness prevention.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The absorbent article uses a composite structure combining the liquid impervious resin film with a cellulose nanofiber layer. The resin film provides moisture perviousness for stuffiness prevention, while the cellulose nanofiber layer provides hygroscopicity to retain moisture and prevent moist feel on the outer surface.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If the liquid impervious resin film has reduced moisture perviousness to prevent moist feel, then the product outer surface stays dry, but stuffiness-preventing property is reduced

Engineering Contradiction:
Improvemoist feel preventionVSAvoidstuffiness prevention
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The cellulose nanofiber layer serves as a mediator that allows the resin film to maintain high moisture perviousness for stuffiness prevention while the nanofiber layer itself handles moisture retention to prevent moist feel on the outer surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Different layers of the absorbent article have different moisture management properties: the liquid impervious resin film has high moisture perviousness for air flow, while the cellulose nanofiber layer has high hygroscopicity for moisture retention, creating localized functional zones that collectively solve both requirements.

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 cellulose nanofiber layer enhances moisture retention and prevents a moist feel on the product outer surface or underwear while maintaining the stuffiness-preventing properties, improving water blocking and strength of the liquid impervious resin film.

Implementation Method 1

The cellulose nanofiber has many OH groups on a surface thereof and has high hygroscopicity. Therefore, when the cellulose nanofiber layer is disposed between the liquid impervious resin film and the exterior nonwoven fabric, moisture that has passed through the liquid impervious resin film is not blocked by the cellulose nanofiber layer.

Methodology Applied
Scientific EffectHygroscopicity: Absorption (physical)

Data Source

PatentEP3689312B1Absorbent article
Publication Date: 2022.08.17 DAIO PAPER CORP
  • EP3689312B1 patent drawingFigure 1
  • EP3689312B1 patent drawingFigure 2
  • EP3689312B1 patent drawingFigure 3

AI summary

To provide an absorbent article due to which a product outer surface or an underwear does not easily impart a moist feel while suppressing reduction in a stuffiness-preventing property. The above problem is solved by an absorbent article including: an absorber 56; a liquid impervious resin film 11 covering a back surface side of the absorber 56; and an exterior nonwoven fabric 12 covering a back surface side of the liquid impervious resin film 11, the liquid impervious resin film 11 having moisture perviousness in a thickness direction, in which a cellulose nanofiber layer 15 is disposed between the liquid impervious resin film 11 and the exterior nonwoven fabric 12.