Water-Absorbent Resin Particles for Fast Uptake and Surface Dryness
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Solution Overview
Problem
Existing water-absorbent resin particles do not provide a dry and soft sensation after absorbing moisture, which is crucial for sanitary products like diapers to ensure quick drying and comfort against the skin.
Innovation Solution
Developed water-absorbent resin particles with an artificial urine permeation speed of 1.0 g/min or more and a contact angle of 70 degrees or less, combined with high water retention capacity and absorption speed, ensuring rapid moisture absorption and quick drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water-absorbent resin particles are used to absorb moisture, then the absorption capacity is improved, but the surface drying speed is insufficient
Solution Approach 1:
The resin particles are designed with heterogeneous surface properties where hydrophilic regions (for absorption) and hydrophobic regions (for rapid surface drying) coexist on the same particle surface, enabling simultaneous moisture uptake and surface drying
Solution Approach 2:
The absorbent is divided into multiple resin particles with different surface characteristics, where some particles prioritize absorption while others facilitate surface drying, working together to resolve the contradiction
2Speed
If the resin particles absorb liquid rapidly, then the absorption speed is improved, but the contact angle increases indicating poor wettability
Solution Approach 1:
The surface energy parameters of the resin particles are optimized by controlling the composition and structure of surface groups, achieving a balance where the contact angle remains low (good wettability) while absorption speed is high
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 resin particles effectively draw moisture into the particles, providing a dry and soft sensation on the surface of absorbent articles by quickly absorbing liquids and retaining them, enhancing user comfort.
Implementation Method 1
the resin particles effectively draw moisture into the particles
Implementation Method 2
water-absorbent resin particles having a specific absorption speed pattern measured by a DW method
Implementation Method 3
a contact angle measured in a test performed in the order of i) and ii) below is 70 degrees or smaller
Data Source
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AI summary
Disclosed is water-absorbent resin particles including: a crosslinked polymer having a monomer unit derived from an ethylenically unsaturated monomer including at least one compound selected from the group consisting of (meth)acrylic acid and a salt thereof, in which a proportion of (meth)acrylic acid and a salt thereof is 70 to 100 mol% with respect to a total amount of monomer units in the crosslinked polymer, an artificial urine permeation speed when the water-absorbent resin particles are swollen tenfold is 1.0 g/min or more and 35.0 g/min or less, a water retention capacity for a physiological saline solution is 32 to 60 g/g, and a contact angle measured in a test performed in the order of i) and ii) is 70 degrees or smaller.