Superabsorbent Polymer Preparation via Low-Temperature Crosslinking

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Solution Overview

Problem

Existing methods for preparing superabsorbent polymers often result in low water content due to high-temperature surface crosslinking, leading to surface damage and increased fine particle generation, which affects physical properties and process stability.

Innovation Solution

A method involving the formation of a water-containing gel polymer, micronization, drying, surface crosslinking, and cooling/hydration using a spade-type cooler to reduce coarse particle formation and enhance water content, ensuring uniform hydration and mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high-temperature surface crosslinking is performed to improve physical properties, then surface crosslinking efficiency is improved, but water content is greatly lowered

Engineering Contradiction:

Improvephysical propertiesVSAvoidwater content

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The patent changes the temperature parameter from high-temperature (140°C or higher) to low-temperature (room temperature or slightly elevated) crosslinking. This parameter change allows the crosslinking reaction to proceed at lower temperatures, preventing excessive water evaporation while still achieving effective surface crosslinking and improved physical properties.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary surface crosslinking at low temperature before the hydrating process. By establishing the crosslinked structure first at low temperature to preserve water content, then subsequently hydrating the particles, the method ensures both physical property improvement and adequate water content retention.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If low water content is accepted to achieve surface crosslinking, then crosslinking reaction is facilitated, but surface damage occurs due to friction

Engineering Contradiction:

Improvecrosslinking reactionVSAvoidsurface damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter to enable crosslinking at low temperature, which facilitates the crosslinking reaction without requiring water evaporation. This maintains adequate water content that acts as a lubricant, preventing surface damage from friction during handling and transport.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful effect of water (which needed to be evaporated for crosslinking) into a beneficial lubricant that prevents surface damage. By performing crosslinking at low temperature, water is retained and serves to reduce friction between particles during handling, preventing surface damage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If low water content superabsorbent polymer is used, then crosslinking is achieved, but fine particle generation increases

Engineering Contradiction:

Improvecrosslinking structureVSAvoidfine particle generation

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the temperature parameter to enable crosslinking at low temperature, which maintains adequate water content in the polymer particles. This adequate water content prevents particle brittleness and reduces fine particle generation during handling, transport, and storage, while still achieving effective crosslinking structure formation.

Inventive Principle:

Principle #35Parameter changes

4Quantity of substance

If water injection through spray nozzle is used to increase water content, then water content is evenly increased, but flow occurs causing contamination

Engineering Contradiction:

Improvewater contentVSAvoidcontamination

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent performs preliminary surface crosslinking at low temperature before the hydrating process. This sequence allows the crosslinked structure to be established first, then water is added to achieve the desired water content without causing flow or contamination issues during the crosslinking step.

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 superabsorbent polymers with improved water retention, reduced coarse particle content, and enhanced absorption performance, preventing surface damage and improving process stability and product quality.

Implementation Method 1

cooling and hydrating the superabsorbent polymer particles... using a spade-type cooler

Methodology Applied

Scientific EffectCooling: Cooling

Implementation Method 2

cooling and hydrating the superabsorbent polymer particles... brought into contact with cooling air and water

Methodology Applied

Scientific EffectHydration: Absorption (physical)

Implementation Method 3

cooling and hydrating the superabsorbent polymer particles... brought into contact with cooling air and water which are injected into the transfer space

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS20230390735A1Preparation method of superabsorbent polymer

Publication Date: 2023.12.07 LG CHEM LTD

AI summary

Provided is a method for preparing a superabsorbent polymer. More particularly, provided is a method for preparing a superabsorbent polymer having a reduced amount of coarse particles with a particle size of more than 850 μm and an improved water content, and exhibiting excellent absorption performances without deviation.