Surface-Crosslinked Superabsorbent Resin Permeability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Superabsorbent polymers (SAPs) face issues with increased stickiness and irreversible agglomeration when absorbing water, leading to poor processability and degradation of physical properties, particularly permeability, during manufacturing, which conventional methods attempt to address using silica and organic solvents but result in decreased productivity and increased costs.

Innovation Solution

A method for preparing surface-crosslinked superabsorbent polymers using a water-soluble polyvalent cationic salt and a polycarbonic acid-based copolymer, in conjunction with a surface crosslinking agent, without silica or organic solvents, to enhance permeability and control particle sizes, thereby improving processability and minimizing property degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If SAPs absorb water to improve moisture absorption capacity, then absorption performance is improved, but stickiness and agglomeration increase causing poor processability

Engineering Contradiction:
Improvemoisture absorption capacityVSAvoidprocessability
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent applies surface crosslinking treatment specifically to the outer layer of SAP particles, creating a hydrophobic crosslinked skin that prevents water adhesion and particle agglomeration, while the inner core maintains high water absorption capacity. This local differentiation resolves the contradiction between absorption performance and processability.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If silica and organic solvents are used to prevent stickiness and improve processability, then ease of operation is improved, but physical properties and permeability degrade

Engineering Contradiction:
ImproveprocessabilityVSAvoidphysical properties
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the SAP surface by introducing crosslinked structures through surface crosslinking treatment. This modifies the surface properties to be hydrophobic and structurally stable, preventing stickiness without requiring silica or organic solvents, thus maintaining physical properties and permeability while improving processability.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional surface crosslinking methods are used to improve permeability, then physical properties are improved, but production cost and process time increase

Engineering Contradiction:
ImprovepermeabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent employs inexpensive crosslinking agents such as sodium carbonate or potassium carbonate instead of costly conventional agents. The surface crosslinking treatment is applied as a brief post-processing step that quickly forms a protective layer, reducing both material costs and process time while achieving the desired permeability improvement.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Productivity

If SAP particles are processed during manufacturing, then production efficiency is improved, but particle sizes become uncontrolled and physical properties degrade

Engineering Contradiction:
Improveproduction efficiencyVSAvoidparticle size control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies surface crosslinking treatment as a preliminary protective measure before subsequent processing steps. This pre-formed crosslinked surface acts as a protective shell that prevents particle breakdown and size variation during handling and processing, enabling efficient manufacturing while maintaining precise particle size control.

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 significantly improves permeability and processability of SAPs, reducing production time and costs while maintaining high physical properties, even after processing, by using a combination of aluminum or zirconium sulfate, polycarbonic acid-based copolymer, and ethylene carbonate, without the need for silica or organic solvents.

Implementation Method 1

surface crosslinking modification with a mixture solution comprising a polycarbonic acid-based copolymer and a surface crosslinking agent

Methodology Applied
Scientific EffectSurface crosslinking: Chemical Bonding

Implementation Method 2

the surface of SAP particles with a water-soluble polyvalent cationic salt and a polycarbonic acid-based copolymer, followed by treatment with a surface crosslinking agent

Methodology Applied
Scientific EffectCrosslinking reaction: Chemical Bonding

Implementation Method 3

pre-treating the superabsorbent base resin by mixing aluminum sulfate or zirconium sulfate

Methodology Applied
Scientific EffectSurface modification: Adsorption

Data Source

PatentEP3235856B1Surface cross-linked super absorbent resin and method for preparing same
Publication Date: 2021.09.01 LG CHEM LTD
  • EP3235856B1 patent drawingFigure 1A~1B
  • EP3235856B1 patent drawingFigure 1C
  • EP3235856B1 patent drawingFigure 2A~2B

AI summary

Disclosed herein is a superabsorbent polymer with a surface crosslinked with a water-soluble polyvalent cationic salt, a polycarbonic acid-based copolymer, and a surface crosslinking agent wherein an improvement is brought about in physical properties, with the concomitant reduction of process time and cost. Also, a method is provided for preparing the surface-crosslinked superabsorbent polymer.