Crosslinked Water-Absorbent Resin Particles for Gel Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing absorbent articles, such as diapers, face issues with gel leakage when using high proportions of water-absorbent resin particles due to swollen gels moving under load, necessitating a reduction in pulp content for forest conservation.
Innovation Solution
Development of a water-absorbent resin particle with a crosslinked polymer containing (meth)acrylic acid and its salt as 70-100% of the monomer units, achieving a water retention capacity of 40 g/g or more, a combined water retention and absorption under 6.21 kPa load of 56 g/g or more, and a water absorption rate of 50 seconds or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the proportion of water-absorbent resin particles in the absorber is increased to reduce pulp content, then forest conservation is achieved and pulp usage is reduced, but swollen gels are likely to move when load is applied and gel leakage occurs
Solution Approach 1:
The patent changes the physical and chemical parameters of the water-absorbent resin particles by controlling the monomer composition ratio ((meth)acrylic acid and its salt at 70-100% by mol), water retention capacity (40 g/g or more), and water absorption rate (50 seconds or less). These parameter adjustments enable the resin to maintain gel stability at high proportions in the absorber, preventing gel leakage while reducing pulp content.
Solution Approach 2:
The patent creates a composite absorber structure consisting of water-absorbent resin particles with specific properties (crosslinked polymer with controlled monomer composition) and minimal pulp content. This composite material approach allows the resin particles to perform multiple functions: absorbing liquid, retaining gel, and maintaining structural integrity under load, thereby reducing pulp content while preventing gel leakage.
2Speed
If the water absorption rate is increased to improve liquid uptake speed, then absorption efficiency is improved, but water retention capacity may be compromised
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: water absorption rate (50 seconds or less) and water retention capacity (40 g/g or more). This is achieved by controlling the monomer composition ratio and crosslinking structure of the polymer, creating a balanced system that rapidly absorbs liquid while effectively retaining the absorbed fluid and preventing gel leakage.
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 particle effectively reduces gel leakage even at high proportions, ensuring efficient liquid absorption and retention in absorbent articles.
Implementation Method 1
a water retention capacity of the water-absorbent resin particle in a physiological saline is 40 g/g or more
Implementation Method 2
a sum of a water retention capacity (g/g) of the water-absorbent resin particle in the physiological saline and a water absorption amount (g/g) of the water-absorbent resin particle under a load of 6.21 kPa is 56 g/g or more
Data Source
AI summary
The present invention relates to a water-absorbent resin particle containing a crosslinked polymer having, as a monomer unit, at least one ethylenically unsaturated monomer selected from the group consisting of (meth)acrylic acid and a salt thereof, in which a ratio of the (meth)acrylic acid and the salt thereof is 70% to 100% by mol with respect to a total amount of the monomer unit in the crosslinked polymer, a water retention capacity of the water-absorbent resin particle in a physiological saline is 40 g/g or more, a sum of a water retention capacity (g/g) of the water-absorbent resin particle in the physiological saline and a water absorption amount (g/g) of the water-absorbent resin particle under a load of 6.21 kPa is 56 or more, and a water absorption rate of the water-absorbent resin particle is 50 seconds or less.