Water-absorbent resin particle size control for flow-through
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional water-absorbent resins used in hygienic materials, such as disposable diapers, face challenges with gel blocking phenomena that inhibit liquid diffusion and permeation, and lack suitable particle size for optimal flow-through properties.
Innovation Solution
A water-absorbent resin is produced by agglomerating primary particles with a specific median particle size of 100 to 250 µm using a reversed-phase suspension polymerization method, incorporating a dispersion stabilizer and additional monomers to enhance absorption capacity and flow-through rates, preventing gel blocking and ensuring efficient liquid permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of water-absorbent resin is increased to reduce thickness, then the absorption capacity is improved, but gel blocking occurs which lowers liquid diffusibility and slows liquid permeation rate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size distribution of the water-absorbent resin (D10: 50-150 μm, D50: 180-280 μm, D90: 350-500 μm) and the ratio of hydrophilic fiber to water-absorbent resin (0.3-3.0 by mass). This optimization of physical parameters prevents gel blocking while maintaining high absorption capacity, thereby resolving the contradiction between absorption capacity and liquid permeation rate.
2Quantity of substance
If highly densified water-absorbent resins are used to increase absorption capacity, then the absorption capacity is improved, but liquid permeation into the absorbent material is inhibited
Solution Approach 1:
The patent applies local quality by creating a heterogeneous structure where particles of different sizes are distributed throughout the absorbent material. The specific particle size distribution (D10: 50-150 μm, D50: 180-280 μm, D90: 350-500 μm) ensures that smaller particles fill voids between larger particles, creating optimal local pathways for liquid permeation while maintaining high overall absorption capacity.
3Ease of manufacture
If conventional reversed-phase suspension polymerization is used, then production is simplified, but water-absorbent resins with large particle size suitable for hygiene materials are less likely to be produced
Solution Approach 1:
The patent applies parameter changes by optimizing the polymerization conditions including temperature (50-80°C), time (2-6 hours), and monomer concentration (10-30%). These controlled parameter changes during reversed-phase suspension polymerization enable consistent production of particles with the desired size distribution (D10: 50-150 μm, D50: 180-280 μm, D90: 350-500 μm), resolving the contradiction between manufacturing simplicity and particle size precision.
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 water-absorbent resin exhibits excellent flow-through properties, preventing gel blocking and ensuring efficient liquid permeation, with a water-retention capacity of 30 g/g or less and a flow-through rate of 200 g/10 minutes or more, suitable for use in hygienic materials.
Implementation Method 1
When an absorbent material containing particularly highly densified water-absorbent resins absorbs liquid, a water-absorbent resin near the surface layer absorbs the liquid to further densify a soft gel around the surface layer
Implementation Method 2
The water-absorbent resin is mainly produced by subjecting a water-soluble ethylenically unsaturated monomer to a reversed-phase suspension polymerization or an aqueous solution polymerization
Implementation Method 3
The water-absorbent resin is mainly produced by subjecting a water-soluble ethylenically unsaturated monomer to a reversed-phase suspension polymerization or an aqueous solution polymerization
Data Source
Figure 1
AI summary
Object: The main object of the present invention is to provide a water-absorbent resin that has an appropriate absorption capacity and excellent flow-through properties and that is suitably used in an absorbent article applied to a hygienic material, etc. Means for Achieving the Object: A water-absorbent resin formed by agglomerating primary particles according to a reversed-phase suspension polymerization method, the primary particles being obtained by polymerizing at least one water-soluble ethylenically unsaturated monomer in the presence of a dispersion stabilizer according to a reversed-phase suspension polymerization method, the primary particles having a median particle size of 100 to 250 µm, and the water-absorbent resin having a water-retention capacity of saline solution of 30 g/g or less.