Superabsorbent Polymer Crosslinking Density Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for preparing superabsorbent polymers often compromise on absorption rate or water retention capacity, particularly in sanitary products, where reducing pulp content necessitates enhanced performance without sacrificing absorbency under load.
Innovation Solution
A method involving crosslinking polymerization of water-soluble ethylenically unsaturated monomers with a thermally degradable internal crosslinking agent and encapsulated foaming agent, followed by heat treatment, to create a superabsorbent polymer with controlled internal and external crosslinking densities, improving absorption rate and water retention capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the degree of internal crosslinking is decreased to increase absorption rate, then absorption rate is improved, but absorbency under load deteriorates
Solution Approach 1:
The patent applies local quality by creating different crosslinking densities in different regions of the superabsorbent polymer particle. The internal crosslinking density is controlled to be lower (faster absorption) while the external surface layer has higher crosslinking density (maintains absorbency under load). This spatial differentiation of properties resolves the contradiction between absorption rate and absorbency under load.
Solution Approach 2:
The patent segments the superabsorbent polymer structure into distinct internal and external regions with different crosslinking characteristics. The internal core region has reduced crosslinking for rapid water uptake, while the external shell region has enhanced crosslinking for maintaining structural integrity and absorbency under load conditions.
2Volume of moving object
If pulp content is reduced to provide thinner sanitary materials, then thickness is reduced, but water retention capacity deteriorates
Solution Approach 1:
The patent changes the chemical and physical parameters of the superabsorbent polymer by controlling crosslinking density and using thermally degradable crosslinking agents. This creates a particle structure with optimized porosity and surface area that enhances water retention capacity per unit volume, allowing reduced pulp content while maintaining or improving water retention performance.
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 a superabsorbent polymer with a rapid absorption rate and enhanced water retention capacity, as evidenced by a centrifuge retention capacity of 40 g/g to 55 g/g and absorption rate of 48 sec or less, suitable for applications in sanitary products.
Implementation Method 1
performing heat-treatment of the base polymer
Implementation Method 2
a method capable of minimizing a reduction in absorbency under load while improving a water retention capacity by controlling internal crosslinking density through an additional heat treatment process
Implementation Method 3
A superabsorbent polymer (SAP) is a synthetic polymeric material capable of absorbing moisture from 500 to 1000 times its own weight
Implementation Method 4
capable of absorbing moisture from 500 to 1000 times its own weight
Data Source
AI summary
A method of preparing a superabsorbent polymer having a rapid absorption rate and an improved water retention capacity by additional heat treatment while using a thermally degradable internal crosslinking agent and an encapsulated foaming agent at the same time during polymerization.A superabsorbent polymer prepared by this method is also provided, the superabsorbent polymer having a centrifuge retention capacity (CRC) of 40 g/g to 55 g/g, as measured according to EDANA method WSP 241.3, and an absorption rate of 48 sec or less, as measured by a vortex method.