Absorbent Resin Structure for Thin Diapers Under Repeat Wetting

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Solution Overview

Problem

Conventional water-absorbing resins used in absorbent articles with low fiber material content, such as thin disposable diapers, exhibit insufficient liquid trapping and absorption capacity on second and subsequent urinations.

Innovation Solution

A water-absorbing resin with a gel expansion force under a load of 4.83 kPa of 26 N or more is used in the absorbent body, enhancing the liquid trapping and absorption capacity on second and subsequent urinations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the ratio of fiber material such as pulp is reduced to achieve thinner absorbent articles, then the thickness and weight are reduced, but the liquid trapping function and absorption capacity on second and subsequent urinations become insufficient

Engineering Contradiction:

ImprovethicknessVSAvoidliquid trapping function

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The invention changes the parameters of the water-absorbing resin by controlling the gel expansion force to be 26 N or more under a load of 4.83 kPa. This parameter change enables the resin to maintain effective liquid trapping capacity even when fiber material content is reduced, allowing thinner absorbent articles to achieve reliable liquid absorption on second and subsequent urinations.

Inventive Principle:

Principle #35Parameter changes

2Length of moving object

If conventional water-absorbing resins are used in absorbent bodies with low fiber material content, then the absorbent article can be made thinner, but the absorption capacity on second and subsequent urinations becomes insufficient

Engineering Contradiction:

ImprovethicknessVSAvoidabsorption capacity

Core Design Contradiction:

Length of moving objectVSQuantity of substance

Solution Approach 1:

The invention specifies that the water-absorbing resin must have a gel expansion force of 26 N or more under a load of 4.83 kPa. This parameter specification ensures that the resin provides sufficient absorption capacity for second and subsequent urinations even in thin absorbent articles with low fiber material content.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite absorbent body consisting of water-absorbing resin and fiber material (pulp or synthetic fiber). By optimizing the composition and the gel expansion force of the resin component, the system achieves both thinness and sufficient absorption capacity for multiple urinations.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If the gel expansion force of water-absorbing resin is increased to improve absorption capacity under load, then the absorption capacity on second and subsequent urinations improves, but the water absorption speed may be affected

Engineering Contradiction:

Improveabsorption capacity under loadVSAvoidwater absorption speed

Core Design Contradiction:

Quantity of substanceVSSpeed

Solution Approach 1:

The invention optimizes the gel expansion force parameter to be 26 N or more under a load of 4.83 kPa, which balances absorption capacity under load with water absorption speed. This parameter optimization ensures that the resin can absorb large amounts of liquid during multiple urinations while maintaining rapid absorption kinetics.

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 absorbent body and article demonstrate improved liquid trapping and absorption capacity on second and subsequent urinations, even with a low proportion of fiber material like pulp.

Implementation Method 1

a water-absorbing resin having a gel expansion force under a load of 4.83 kPa of 26 N or more

Methodology Applied

Scientific EffectGel expansion: Gel

Data Source

PatentUS12558451B2Absorbent body, water-absorbing resin, and absorbent article

Publication Date: 2026.02.24 NIPPON SHOKUBAI CO LTD

AI summary

Provided is an absorbent body that, for example, in a case where the absorbent body has been used in an absorbent article, such as a thin disposable diaper, having an absorbent body with a low proportion of fiber material (hydrophilic fibers) such as pulp, enables the absorbent article such as a disposable diaper to have an improved liquid trapping function on second and subsequent urinations over the conventional ones and particularly to have an increased amount of liquid trapped under load on the second and subsequent urinations over the conventional ones. Also provided is a water-absorbing resin that is used in the absorbent body and has an increased absorption capacity under load on the second and subsequent urinations over the conventional ones.The absorbent body includes a water-absorbing resin having a gel expansion force under a load of 4.83 kPa of 26 N or more.