Superabsorbent Polymer Chopping Index Optimization
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Solution Overview
Problem
Current methods for preparing superabsorbent polymers fail to achieve a balance between high absorption ratio, absorption speed, and permeability, which are essential for modern applications such as thin diapers, where existing techniques either prioritize absorption ratio over speed or speed over ratio.
Innovation Solution
A method involving crosslinking polymerization of water-soluble ethylenically unsaturated monomers with an internal crosslinking agent and expanding agent, followed by chopping and surface modification, under specific chopping index conditions using a screw type extruder, to produce hydrogel polymers with expanded and porous particles that exhibit enhanced absorption properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydrogel is chopped to improve absorption speed and permeability, then absorption speed and permeability are improved, but absorption ratio deteriorates due to damage to hydrogel structure
Solution Approach 1:
The invention changes the physical parameters of the hydrogel by controlling the chopping index (a quantitative parameter combining rotational speed, solid content, and aperture ratio) within a specific range of 15-30. This parameter optimization allows the hydrogel to be chopped into particles with appropriate size and structure, achieving both high absorption speed and high absorption ratio without structural damage
2Speed
If internal crosslinking agent is used to improve absorption speed and permeability, then absorption speed and permeability are improved, but absorption ratio deteriorates
Solution Approach 1:
The invention optimizes the concentration parameter of the internal crosslinking agent within a specific range (0.01-0.1 wt% based on monomer total weight) and combines it with controlled chopping parameters. This dual parameter optimization ensures that the crosslinking density is sufficient to provide structural integrity and maintain high absorption ratio, while still allowing for fast absorption kinetics
3Speed
If hydrogel is chopped with high intensity to improve absorption speed, then absorption speed is improved, but water soluble components are damaged and absorption ratio deteriorates
Solution Approach 1:
The invention precisely controls the chopping intensity by optimizing the chopping index parameter (15-30) and related parameters (rotational speed 1000-3000 rpm, aperture ratio 10-30%). This controlled parameter range provides sufficient mechanical energy to create particles with good absorption speed while avoiding excessive intensity that would damage water-soluble components and reduce absorption ratio
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 improved absorption ratio, absorption speed, and permeability, as evidenced by increased centrifuge retention capacity, absorbency under pressure, and saline flow conductivity, making them suitable for ultra-thin hygienic products.
Implementation Method 1
conducting crosslinking polymerization of water soluble ethylenically unsaturated monomers having acid groups of which at least a part are neutralized, in the presence of an internal crosslinking agent and an expanding agent to form hydrogel polymer comprising a first crosslinked polymer
Implementation Method 2
chopping the hydrogel polymer while pushing the hydrogel polymer to a perforated panel having a plurality of holes using a screw type extruder equipped inside of a cylindrical mill
Data Source
AI summary
The present invention relates to a method for preparing superabsorbent polymer. The method for preparing superabsorbent polymer according to the present invention enables providing superabsorbent polymer having excellent absorption ratio, absorption speed and permeability.