Superabsorbent Polymer Initial Absorption via Foaming Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for preparing superabsorbent polymers, such as reverse-phase suspension polymerization and foaming agents, face challenges in achieving uniform porous structures and high initial absorption properties, which are essential for improving dryness in sanitary materials like diapers.

Innovation Solution

A method involving crosslinking polymerization of water-soluble ethylene-based unsaturated monomers with a foaming agent and surfactant, followed by surface-crosslinking, to create superabsorbent polymer particles with improved initial absorption properties, where the time to reach the maximum foaming point is controlled within 100 seconds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If reverse-phase suspension polymerization is used to prepare superabsorbent polymers, then polymerization can be performed, but it requires additional separate processes, uses large amounts of organic solvents, and has difficulty in recovering prepared superabsorbent polymers

Engineering Contradiction:
Improveease of polymerization processVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts and removes the problematic reverse-phase suspension polymerization process entirely, replacing it with direct polymerization in an aqueous medium. This eliminates the need for separate organic solvent removal steps and simplifies the overall manufacturing process while maintaining polymerization effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a water-soluble crosslinking agent as an intermediary substance that enables crosslinking polymerization to occur directly in aqueous medium without requiring organic solvents. This mediator allows the polymerization process to proceed efficiently while avoiding the complications of solvent removal and recovery.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If foaming agents are used to provide porosity in superabsorbent polymers, then pores can be formed inside the polymer, but it is difficult to obtain uniform porous particles

Engineering Contradiction:
Improveporosity uniformityVSAvoidease of particle formation
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the key parameter of foaming mechanism by using a water-soluble crosslinking agent that generates gas bubbles in situ during polymerization. This approach produces more uniform pore distribution and particle morphology compared to traditional foaming agents, achieving both manufacturing precision and ease of particle formation.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If superabsorbent polymer particles are included as multiple layers in sanitary materials, then liquid absorption capacity is increased, but initial absorption properties must be improved to enhance dryness

Engineering Contradiction:
Improveabsorption capacityVSAvoidinitial absorption performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the surface layer has different properties from the core. The surface is engineered with enhanced hydrophilicity and porosity to improve initial absorption performance, while the core maintains high absorption capacity. This resolves the contradiction between quantity and reliability of absorption.

Inventive Principle:
Principle #3Local quality

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 enhances the initial absorption properties of superabsorbent polymers, resulting in faster absorption rates and improved dryness, making them suitable for use in sanitary materials.

Implementation Method 1

performing crosslinking polymerization of a water-soluble ethylene-based unsaturated monomer having acidic groups which are at least partially neutralized in the presence of an internal crosslinking agent and a surfactant to form a hydrogel polymer

Methodology Applied
Scientific EffectCrosslinking polymerization: Chemical Bonding

Implementation Method 2

a maximum foaming point reaches within 100 seconds from a polymerization initiation point

Methodology Applied
Scientific EffectFoaming: Foam

Implementation Method 3

performing crosslinking polymerization of a water-soluble ethylene-based unsaturated monomer having acidic groups which are at least partially neutralized in the presence of an internal crosslinking agent and a surfactant to form a hydrogel polymer containing a first crosslinked polymer

Methodology Applied
Scientific EffectGas generation: Bubble

Implementation Method 4

performing crosslinking polymerization of a water-soluble ethylene-based unsaturated monomer having acidic groups which are at least partially neutralized in the presence of an internal crosslinking agent and a surfactant

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Implementation Method 5

performing surface-crosslinking of the base polymer powder by heat treatment in the presence of a surface crosslinking solution to form superabsorbent polymer particles

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 6

performing surface-crosslinking of the base polymer powder by heat treatment in the presence of a surface crosslinking solution

Methodology Applied
Scientific EffectSurface crosslinking: Chemical Bonding

Implementation Method 7

it is necessary that the superabsorbent polymer basically exhibits high absorption performance and absorption rate

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 8

excellent initial absorption properties are required

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS11020725B2Method of preparing superabsorbent polymer
Publication Date: 2021.06.01 LG CHEM LTD

AI summary

A superabsorbent polymer according to the present invention has excellent initial absorption properties, and thus it may be used in sanitary materials such as diapers, etc., thereby exhibiting excellent performances.