Super Absorbent Polymer Surface Cross-Linking Without Epoxy
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Solution Overview
Problem
Existing super absorbent polymers face challenges in achieving high absorption performance under pressure while maintaining anti-caking properties, particularly when using silica or clay as cross-linking agents, which can lead to reduced water retention capacity and separation issues, especially in hygiene products like diapers, and there is a need for a method that excludes hazardous chemical substances.
Innovation Solution
A preparation method involving the formation of hydrogel polymers through cross-linking with a non-epoxy surface cross-linking agent, followed by surface cross-linking at controlled temperatures, including a first raising and then lowering of temperature stages, to create super absorbent polymer particles with improved anti-caking and absorption properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silica or clay is added as cross-linking agent to improve permeability, then permeability is improved, but water retention capacity and absorbency under pressure are reduced
Solution Approach 1:
The patent changes the chemical composition parameters by replacing traditional silica/clay cross-linking agents with a two-stage cross-linking system using glycerol monomethacrylate (internal) and ethylene glycol dimethacrylate (surface), optimizing the molecular structure and cross-linking density to achieve both high permeability and water retention capacity
Solution Approach 2:
The patent creates a composite polymer structure combining polyacrylic acid chains with specific cross-linking agents, forming a network that integrates porous structure for permeability with cross-linked bonds for water retention, achieving synergistic performance
2Quantity of substance
If silica or clay is added to improve permeability, then permeability is improved, but separation occurs during transport due to external physical impact
Solution Approach 1:
The patent merges the permeability-enhancing function and the anti-caking function into a single integrated polymer network structure, where the cross-linked gel particles maintain both porous channels for fluid flow and structural integrity for transport stability, eliminating the need for separate silica/clay additives
3Stability of the object's composition
If epoxy-based surface cross-linking agent is used to achieve anti-caking, then anti-caking performance is improved, but chemical hazards are introduced
Solution Approach 1:
The patent replaces hazardous epoxy-based cross-linking agents with biocompatible, non-toxic alternatives (glycerol monomethacrylate and ethylene glycol dimethacrylate) that provide equivalent anti-caking performance without chemical hazards, making the product safe for hygiene applications
Solution Approach 2:
The patent changes the chemical safety parameters by selecting cross-linking agents with favorable toxicological profiles, specifically using glycerol-derived and ethylene glycol-derived monomers that are recognized as safe for contact with skin and mucous membranes
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 maintains excellent absorption-related physical properties and anti-caking performance of super absorbent polymers, even under high temperature and humidity conditions, without using epoxy-based agents that pose chemical hazards.
Implementation Method 1
forming a hydrogel polymer by cross-linking polymerizing a water-soluble ethylene-based unsaturated monomer
Implementation Method 2
polymerizing a water-soluble ethylene-based unsaturated monomer having at least partially neutralized acidic groups in the presence of a polymerization initiator
Data Source
AI summary
The present disclosure relates to a preparation method of a super absorbent polymer, and there is provided a preparation method of a super absorbent polymer capable of achieving anti-caking while maintaining excellent absorption-related physical properties of super absorbent polymer particles by performing surface cross-linking at a relatively lower temperature than before using a non-epoxy cross-linking agent without an epoxy-based surface cross-linking agent, which is a controversial source of chemical hazards.