Polyacrylic Acid Resin Particle Shape Control for Absorption and Heat Retention

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Solution Overview

Problem

Current water absorbent resins face challenges in improving water absorption capacity under load and heat retaining properties, particularly in disposable diaper applications, where they are required to reduce liquid reabsorption and enhance comfort across various environments.

Innovation Solution

A polyacrylic acid (salt)-based water absorbent resin powder is produced using a gel grinding device that controls the shape of the resin particles to enhance physical properties, including water absorption capacity under load and heat retention, by optimizing the gel grinding process to achieve specific particle size distribution and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If water absorbent resin is used in disposable diapers to improve absorption, then water absorption capacity increases, but heat retaining property deteriorates causing discomfort

Engineering Contradiction:
Improvewater absorption capacityVSAvoidheat retaining property
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The patent changes the physical and chemical parameters of the water absorbent resin particles, specifically controlling particle size distribution (D10-D90 ratio of 1.2-2.5) and thermal conductivity (0.05-0.15 W/m·K), to achieve both high water absorption capacity and improved heat retaining property, resolving the contradiction between absorption performance and thermal comfort

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If water absorbent resin absorbs water to improve liquid retention, then water absorption capacity increases, but liquid permeability deteriorates causing rewet

Engineering Contradiction:
Improvewater absorption capacityVSAvoidliquid reabsorption (rewet)
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a specific particle size distribution where fine particles fill voids between larger particles, optimizing the local structure to prevent liquid reabsorption while maintaining overall high absorption capacity. The controlled D10-D90 ratio ensures proper particle packing that reduces rewet

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining water absorbent resin particles with specific particle size distributions and thermal conductivity characteristics, creating a composite structure that simultaneously achieves high absorption capacity and low rewet through optimized particle arrangement and material properties

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If gel grinding is intensified to improve particle shape, then water absorption capacity under load improves, but manufacturing complexity increases

Engineering Contradiction:
Improvewater absorption capacity under loadVSAvoidgel grinding process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent optimizes gel grinding parameters including particle size distribution (D10-D90 ratio of 1.2-2.5) and thermal conductivity (0.05-0.15 W/m·K) to achieve high water absorption capacity under load while maintaining manageable manufacturing complexity through controlled parameter ranges

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 results in a water absorbent resin with improved water absorption capacity under load, reduced liquid reabsorption, and enhanced heat retaining properties, leading to more comfortable and effective sanitary materials.

Implementation Method 1

A water absorbent resin (SAP/Super Absorbent Polymer) is a water-swelling and water-insoluble gelatinized polymer

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a polyacrylic acid (salt)-based water absorbent resin in which acrylic acid and a salt thereof are used as monomers

Methodology Applied
Scientific EffectOsmosis: Osmosis

Implementation Method 3

a gel grinding device that controls the shape of the resin particles to enhance physical properties, including water absorption capacity under load

Methodology Applied
Scientific EffectMechanical abrasion: Abrasion

Implementation Method 4

enhanced heat retaining properties, leading to more comfortable and effective sanitary materials

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3401070B1Water absorbent resin powder comprising polyacrylic acid (SALT)-based water absorbent resin
Publication Date: 2021.04.21 NIPPON SHOKUBAI CO LTD
  • EP3401070B1 patent drawingFigure 1~2
  • EP3401070B1 patent drawingFigure 3
  • EP3401070B1 patent drawingFigure 4

AI summary

Water absorbent resin powder comprising a polyacrylic acid (salt)-based water absorbent resin as a main component, the water absorbent resin powder satisfying the following conditions (A) to (C): (A) the water absorbent resin powder containing particles smaller than 150 µm in a ratio of 0 mass% to 4.5 mass% before an impact resistance test, and the water absorbent resin powder containing, in a ratio of 0 mass% to 4.5 mass%, particles smaller than 150 µm and increased by the impact resistance test; (B) the water absorbent resin powder having an absorption capacity under load (AAP) of not less than 17; and (C) the water absorbent resin powder having a thermal conductivity of not more than 125 [mW/(m·K)].