Superabsorbent Polymer Preparation Using Encapsulated Foaming Agent

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Solution Overview

Problem

Existing methods for preparing superabsorbent polymers face challenges in achieving high absorbency and rapid absorption rates, particularly when using carbonate-based foaming agents, which can lead to reduced bulk density and excessive fine particle generation.

Innovation Solution

A method involving the polymerization of monomers with acidic groups neutralized by potassium hydroxide in the presence of an encapsulated foaming agent, which includes a hydrocarbon core and a thermoplastic resin shell, to enhance the osmotic pressure and crosslinked structure of the polymer, thereby improving initial absorbency and absorption rate without using surfactants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a carbonate-based foaming agent is used to improve absorption rate, then the absorption rate is improved, but apparent density is lowered and fine particles are generated in large amounts

Engineering Contradiction:
Improveabsorption rateVSAvoidapparent density
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the foaming agent from carbonate-based to a specific organic compound (2,2-dimethyl-1,3-propanediol) with controlled molecular structure. This parameter change achieves rapid gas generation for high absorption rate while the controlled decomposition characteristics prevent excessive foam expansion, thereby maintaining apparent density and reducing fine particle generation during pulverization.

Inventive Principle:
Principle #35Parameter changes

2Speed

If a carbonate-based foaming agent is used to improve absorption rate, then the absorption rate is improved, but fine particles are generated in large amounts during pulverization

Engineering Contradiction:
Improveabsorption rateVSAvoidfine particle generation
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the foaming agent's chemical parameters to use 2,2-dimethyl-1,3-propanediol, which decomposes at controlled rates during polymerization. This produces sufficient gas for rapid absorption performance while avoiding excessive foam formation that would create fragile structures prone to generating fine particles during subsequent pulverization processing.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If multiple layers of superabsorbent polymer particles are used to improve liquid absorption efficiency, then absorption efficiency is improved, but basic absorption performance and absorption rate must be maintained at high levels

Engineering Contradiction:
Improveliquid absorption efficiencyVSAvoidabsorption performance consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent optimizes the molecular weight distribution and crosslinking density parameters of the superabsorbent polymer to ensure each particle layer maintains high absorption performance. The controlled polymerization conditions and foaming agent selection create particles with consistent internal structures, ensuring reliable absorption performance across multiple layers without requiring excessive layering.

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 method results in a superabsorbent polymer with improved 1 min-absorbency and absorption rate, suitable for applications in sanitary products, while maintaining structural integrity and reducing fine particle issues.

Implementation Method 1

an encapsulated foaming agent, which includes a hydrocarbon core and a thermoplastic resin shell

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

a thermoplastic resin shell

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentUS11918978B2Method of preparing superabsorbent polymer
Publication Date: 2024.03.05 LG CHEM LTD

AI summary

Provided is a method of preparing a superabsorbent polymer. More specifically, provided is a method of preparing a superabsorbent polymer capable of exhibiting improved initial absorbency and a rapid absorption rate by polymerizing monomers having acidic groups, of which part is neutralized with a basic material including potassium hydroxide, in the presence of an encapsulated foaming agent.