Surface Crosslinked Super Absorbent Polymer for Liquid Permeability
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Solution Overview
Problem
Conventional super absorbent polymers face challenges in maintaining excellent liquid permeability while preserving high water absorption properties, often resulting in sticky surfaces and reduced centrifuge retention capacity due to high water-soluble component content.
Innovation Solution
The development of surface crosslinked polymer particles from water-soluble ethylene-based unsaturated monomers, with controlled molecular weight distribution of the water-soluble component, achieved through a specific polymerization and surface crosslinking process, to minimize elution and enhance permeability without compromising absorbency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content of water-soluble component is increased to improve liquid absorption property, then water absorption property is improved, but liquid permeability is reduced and surface stickiness increases
Solution Approach 1:
The patent segments the polymer structure into crosslinked networks and controlled water-soluble components, where the crosslinked portions provide structural integrity and prevent excessive elution while the controlled water-soluble portions maintain absorption capacity without causing surface stickiness
Solution Approach 2:
The patent changes the molecular weight parameters of the water-soluble component to specific ranges (10,000-100,000 g/mol) and controls the ratio of water-soluble component to total polymer (5-50 wt%), optimizing the balance between absorption property and surface stickiness prevention
2Quantity of substance
If the content of water-soluble component is increased to improve liquid absorption property, then water absorption property is improved, but centrifuge retention capacity is reduced
Solution Approach 1:
The patent optimizes the molecular weight distribution of water-soluble components within specific ranges (10,000-100,000 g/mol) and controls their content ratio (5-50 wt% of total polymer) to maintain centrifuge retention capacity while preserving water absorption property
Solution Approach 2:
The patent creates a composite structure combining crosslinked polymer networks with controlled water-soluble components, where the crosslinked portion provides structural stability for centrifuge retention while the water-soluble portion contributes to absorption capacity
3Object-generated harmful factors
If surface crosslinking is performed to reduce water-soluble component elution, then surface stickiness is reduced, but liquid permeability may be affected
Solution Approach 1:
The patent applies surface crosslinking specifically to the outer surface of the polymer particles, creating a crosslinked skin layer that prevents water-soluble component elution and surface stickiness, while the interior remains porous to maintain liquid permeability
Solution Approach 2:
The patent maintains a porous internal structure within the polymer particles that allows liquid penetration and transport, while the surface crosslinked layer provides a selective barrier that prevents excessive elution without blocking liquid permeability
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 resulting super absorbent polymer exhibits improved liquid permeability and centrifuge retention capacity, with reduced discomfort and maintained absorbency under load, achieved by controlling the molecular weight distribution of the water-soluble component and optimizing the surface crosslinking process.
Implementation Method 1
heating or irradiating a monomer composition to form a hydrogel polymer by polymerization, wherein the monomer composition contains water-soluble ethylene-based unsaturated monomers and a polymerization initiator
Implementation Method 2
heating a mixture of the particles and a surface crosslinking solution at a temperature ranging from 180 to 200° C. to form surface crosslinked polymer particles of the super absorbent polymer
Implementation Method 3
drying the hydrogel polymer
Data Source
AI summary
The present invention relates to a super absorbent polymer and a preparation method thereof. The super absorbent polymer includes surface crosslinked polymer particles prepared by surface crosslinking of particles of a base resin, wherein the base resin is polymerized from a monomer composition including water-soluble ethylene-based unsaturated monomers, and a water-soluble component, wherein the water-soluble component has a ratio (dwt/d(log M)) of 0.9 or less over molecular weights (M) ranging from 100,000 to 300,000 when measured from an eluted solution after swelling the super absorbent polymer for 1 hour, and wherein the content of the water-soluble component is 5% by weight or less, based on the total weight of the super absorbent polymer, when measured after swelling the super absorbent polymer for 1 hour. The super absorbent polymer has excellent liquid permeability even when swollen without a reduction in centrifuge retention capacity or absorbency under load while having improved permeability.