Absorbent Body Resin Fixing Agent Swelling Contradiction

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Solution Overview

Problem

Existing absorbent bodies with water absorbent resin powders face reduced absorption performance due to adhesives with rubber elasticity hindering the swelling of resin powders, limiting their supporting properties.

Innovation Solution

A water absorbent resin powder is coated with a fixing agent that is a copolymer with specific acid value and structural units derived from olefin and vinyl aromatic compounds, providing high affinity to both the resin and base material, allowing for unhindered swelling and improved supporting properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive having rubber elasticity is used to fix water absorbent resin powder, then supporting property is improved, but absorption performance is lowered due to hindered swelling

Engineering Contradiction:
Improvesupporting propertyVSAvoidabsorption performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the key parameter of the fixing agent from rubber elasticity to low elasticity by selecting specific polymers (polyethylene, polypropylene, polyester) with elastic modulus of 100 MPa or less. This parameter change allows the fixing agent to provide sufficient supporting property while having minimal hindering effect on the swelling of water absorbent resin powder, thus resolving the contradiction between supporting property and absorption performance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If fixing agent with low elasticity is used to allow swelling, then absorption performance is improved, but supporting property is reduced

Engineering Contradiction:
Improveabsorption performanceVSAvoidsupporting property
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention uses a composite structure where water absorbent resin powder particles are embedded in a matrix of low-elasticity polymer fixing agent. The fixing agent forms a continuous phase that provides mechanical support and anchors the resin particles, while the resin particles maintain their ability to swell and absorb fluid. This composite approach allows simultaneous achievement of supporting property and absorption performance.

Inventive Principle:
Principle #40Composite materials

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 an absorbent body with enhanced water absorbent resin powder supporting properties, ensuring optimal absorption performance by using a fixing agent that breaks easily under swelling pressure, maintaining high affinity and mechanical strength.

Implementation Method 1

The water absorbent resin takes body fluid inside voids between the polymer chains thereof, and thus the water absorbent resin swells if it absorbs body fluid.

Methodology Applied
Scientific EffectSwelling: Absorption (physical)

Implementation Method 2

a water absorbent resin powder fixed on a base material by a resin

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3600201B1Absorbent body and absorbent article comprising the same
Publication Date: 2021.05.26 LIVEDO CORP
  • EP3600201B1 patent drawingFigure 1
  • EP3600201B1 patent drawingFigure 2
  • EP3600201B1 patent drawingFigure 3

AI summary

[Object] To provide an absorbent body comprising a water absorbent resin powder fixed on a base material by a resin and having excellent water absorbent resin powder supporting property. [Solution] The present invention provides an absorbent body comprising: a base material and a water absorbent resin powder fixed on the base material by a fixing agent, wherein the base material is a fiber base material having a mass per unit area in a range from 10 g/m2 to 500 g/m2, and the fixing agent is a copolymer having an acid value in a range from 20 mgKOH/g to 150 mgKOH/g and including a structural unit (X) derived from at least one monomer selected from the group consisting of an olefin and a vinyl aromatic compound and a structural unit (Y) derived from a monomer having an acidic group.