Absorbent Article Surface Material Pore Distribution

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Solution Overview

Problem

Existing absorbent articles face a trade-off between rapid liquid admission and maintaining a dry surface, with fine-pored materials providing protection against rewetting but low liquid admission capacity, and coarse-pored materials offering good liquid admission but poor rewetting protection.

Innovation Solution

An absorbent article design featuring a liquid-permeable covering layer with a nonwoven material having a pore volume distribution curve with a maximum at a pore radius greater than or equal to 50 μm and a wetting angle of at least 120°, combined with a fibrous liquid-transfer layer having a pore volume distribution curve with a maximum at 105 to 325 μm, optimizing both liquid admission and surface dryness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fine-pored liquid-permeable covering material is used, then protection against rewetting is improved, but liquid-admission capacity deteriorates

Engineering Contradiction:

Improveprotection against rewettingVSAvoidliquid-admission capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The liquid-permeable covering layer is divided into multiple sublayers with different pore sizes and functions. The top layer has finer pores for rewetting protection, while lower layers have coarser pores for rapid liquid admission, allowing each sublayer to specialize in one function rather than requiring a single material to do both

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The covering layer combines different types of fibrous materials with complementary properties - hydrophobic fibers for the top layer to provide rewetting barrier, and hydrophilic fibers in lower layers for rapid wicking and admission, creating a composite structure that achieves both contradictory requirements simultaneously

Inventive Principle:

Principle #40Composite materials

2Productivity

If a coarse-pored surface material is used, then liquid-admission capacity is improved, but protection against rewetting deteriorates

Engineering Contradiction:

Improveliquid-admission capacityVSAvoidprotection against rewetting

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The covering layer is segmented into functional zones where the top surface layer has fine pores for rewetting protection while underlying layers have coarse pores for rapid liquid admission, allowing the system to achieve both fine-pored and coarse-pored benefits in different locations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Intermediate layers with medium pore sizes and specific hydrophilicity act as mediators between the fine-pored top layer and coarse-pored lower layers, facilitating liquid transport while maintaining the gradient structure that enables both rapid admission and rewetting protection

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a fine-pored material is used, then protection against rewetting is improved, but liquid retention increases making the surface feel wet

Engineering Contradiction:

Improveprotection against rewettingVSAvoidliquid retention and wet feel

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

Different regions of the covering layer have different liquid retention characteristics - the top layer is designed to feel dry to the user while lower layers retain liquid for absorption, creating local quality differences that satisfy both user comfort and absorption requirements

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The hydrophilicity and pore size parameters are varied through the thickness of the covering layer, with the top layer having lower hydrophilicity and finer pores for dry feel, while lower layers have higher hydrophilicity and coarser pores for liquid retention and transport

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 enables absorbent articles with excellent liquid-handling properties, ensuring rapid liquid uptake and maintaining surface dryness, with the liquid-transfer layer's properties significantly influencing dryness, allowing for effective prediction of material behavior in absorbent applications.

Implementation Method 1

a nonwoven material with a pore volume distribution curve with a maximum at a pore radius greater than or equal to 50 μm and with a wetting angle of at least 120°

Methodology Applied

Scientific EffectHydrophobicity: Hydrophobe

Implementation Method 2

a fibrous layer with a pore volume distribution curve with a maximum at a pore radius of from 105 to 325 μm

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 3

an absorbent body enclosed between the covering layers

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS7763770B2Absorbent article with improved surface material

Publication Date: 2010.07.27 ESSITY HYGIENE & HEALTH AB

AI summary

An absorbent article comprises an absorbent body, a liquid-permeable covering layer arranged over a first surface on the absorbent body, and a liquid-permeable liquid-transfer layer arranged between the absorbent body and the liquid-permeable covering layer. The liquid-permeable covering layer comprises a nonwoven material with a pore volume distribution curve with a maximum at a pore radius greater than or equal to 50 μm and with a wetting angle of at least 120°. The liquid-transfer layer comprises a fibrous layer with a pore volume distribution curve with a maximum at a pore radius of from 105 to 325 μm.