Superabsorbent Polymer Surface Crosslinking for Liquid Permeability
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Solution Overview
Problem
Superabsorbent polymers face challenges in maintaining high liquid permeability and absorption rates, especially after pulverization, due to the separation of inorganic particles during processing, which affects their physical properties and performance in applications like sanitary products.
Innovation Solution
A method involving crosslinking polymerization of water-soluble ethylene-based unsaturated monomers, followed by drying, pulverization, and surface-crosslinking with a thickener and surface crosslinking agent to form a surface-crosslinked layer, minimizing physical property deterioration and enhancing liquid permeability without the need for excessive inorganic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If inorganic particles are added to improve liquid permeability, then liquid permeability is improved, but absorption rate under pressure is lowered
Solution Approach 1:
The patent changes the physical and chemical parameters of the superabsorbent polymer by controlling the degree of neutralization (50-95%), crosslinking density, and particle size distribution (10-500 μm). These parameter adjustments optimize both liquid permeability and absorption rate under pressure without requiring inorganic particles.
2Quantity of substance
If inorganic particles are used to enhance liquid permeability, then liquid permeability is improved, but inorganic particles are separated during pulverization and size-sorting
Solution Approach 1:
The patent extracts and eliminates inorganic particles from the superabsorbent polymer composition entirely. Instead, it uses purely organic polymer components with controlled crosslinking and neutralization to achieve the desired liquid permeability, thereby preventing composition instability during pulverization.
3Reliability
If absorption rate under pressure is enhanced, then absorption performance is improved, but liquid permeability is reduced
Solution Approach 1:
The patent applies local quality by creating different functional zones within the polymer structure: highly crosslinked regions for maintaining structural integrity and absorption under pressure, and less crosslinked regions with appropriate porosity for liquid permeability. This is achieved through controlled crosslinking density and neutralization degree in different parts of the polymer matrix.
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 results in superabsorbent polymers with minimized physical property deterioration after pulverization, maintaining excellent liquid permeability and absorption rates, as evidenced by specific performance metrics such as centrifuge retention capacity, absorbency under load, and gel bed permeability.
Implementation Method 1
additionally crosslinking the surface of the base polymer powder in the presence of a thickener having a weight average molecular weight of 300 g/mol to 1,000,000 g/mol and a surface crosslinking agent to form a surface-crosslinked layer
Implementation Method 2
A superabsorbent polymer (SAP) is a synthetic polymeric material capable of absorbing moisture from about 500 to 1000 times its own weight
Implementation Method 3
performing crosslinking polymerization of a monomer mixture including water-soluble ethylene-based unsaturated monomers having acidic groups which are at least partially neutralized, in the presence of an internal crosslinking agent to form a water-containing gel polymer
Data Source
AI summary
The present invention relates to a method for preparing a superabsorbent polymer, and a superabsorbent polymer prepared thereby. A superabsorbent polymer prepared by the preparation method exhibits minimized deterioration of physical properties after being pulverized, and thus basic absorbance performance is excellent and an excellent liquid permeability and absorbance rate can be exhibited.