Water-Absorbent Resin Crosslinking for Low-Dissolution Recycling

Solution Overview

Problem

Existing methods for regenerating water-absorbent resin from used sanitary products fail to maintain high water-absorbing ability while minimizing polymer dissolution.

Innovation Solution

A production method involving the cleavage of crosslinked structures in water-absorbent resin to form polymer solutions, followed by crosslinking through covalent bonds to create water-absorbent resin particles with high absorption performance and reduced dissolved matter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the crosslinked structure of water-absorbent resin is destroyed by predetermined treatment, then the polymer component can be collected and reused, but the water-absorbing ability decreases and polymer dissolution increases

Engineering Contradiction:

ImproverecyclabilityVSAvoidwater-absorbing ability

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

The patent applies preliminary action by performing crosslinking treatment on the polymer before regeneration. The polymer obtained by decomposing the water-absorbent resin is crosslinked to form a crosslinked polymer, which prevents excessive dissolution during subsequent regeneration processes while maintaining water-absorbing ability. This preliminary crosslinking step ensures that the polymer structure is stabilized before the regeneration process begins.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by controlling the molecular weight of the polymer and the degree of crosslinking. By adjusting these parameters, the patent achieves an optimal balance between recyclability and water-absorbing ability. The crosslinked polymer with controlled parameters maintains structural integrity during regeneration while enabling effective collection and reuse.

Inventive Principle:

Principle #35Parameter changes

2Ease of repair

If the crosslinked structure of water-absorbent resin is destroyed by predetermined treatment, then the polymer component can be collected and reused, but the amount of dissolved polymer increases

Engineering Contradiction:

ImproverecyclabilityVSAvoidpolymer dissolution

Core Design Contradiction:

Ease of repairVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by performing crosslinking treatment on the polymer before regeneration. The polymer obtained by decomposing the water-absorbent resin is crosslinked to form a crosslinked polymer, which prevents excessive dissolution during subsequent regeneration processes while maintaining water-absorbing ability. This preliminary crosslinking step ensures that the polymer structure is stabilized before the regeneration process begins.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional regeneration methods are used, then the production process is simple, but both water-absorbing ability maintenance and polymer dissolution suppression cannot be achieved simultaneously

Engineering Contradiction:

Improveprocess simplicityVSAvoidwater-absorbing ability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by performing crosslinking treatment on the polymer before regeneration. The polymer obtained by decomposing the water-absorbent resin is crosslinked to form a crosslinked polymer, which prevents excessive dissolution during subsequent regeneration processes while maintaining water-absorbing ability. This preliminary crosslinking step ensures that the polymer structure is stabilized before the regeneration process begins.

Inventive Principle:

Principle #10Preliminary action

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 method produces water-absorbent resin particles with enhanced water absorption capacity and minimal polymer dissolution, suitable for recycling and reuse.

Implementation Method 1

in the crosslinking step, the polymer solution is gelled

Methodology Applied

Scientific EffectGelation: Gel

Implementation Method 2

a crosslinking step of crosslinking the polymer through a covalent bond to form the crosslinked polymer

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 3

the water-absorbent resin swells by containing moisture so that excrement can be absorbed

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP4667517A1Water-absorbent resin particles and production method therefor, absorbent body, and absorbent article

Publication Date: 2025.12.24 SUMITOMO SEIKA CHEM CO LTD

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AI summary

A production method for water-absorbent resin particles containing a crosslinked polymer includes a preparation step of preparing a polymer solution that contains a polymer and a solvent, and a crosslinking step of crosslinking the polymer through a covalent bond to form the crosslinked polymer. The water-absorbent resin particles have a dissolution component index of 2 × 10-3 to 6 × 10-3, which is represented by the following equation. dissolutioncomponentindex=dissolvedmatterg/g/CRCg/g