Water-Absorbing Resin With Dry-Up Index for Low-Content Backflow Control
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Solution Overview
Problem
Existing absorbent materials in hygiene products face challenges in balancing absorption properties and texture, with increased water-absorbent resin content often impairing texture and making uniform dispersion difficult, leading to unsatisfactory backflow of absorbed liquids.
Innovation Solution
A water-absorbent resin with a specific dry-up index, calculated by the product of overall absorption capacity and water absorption rate, is developed, utilizing a polymerization method with controlled molar ratios of ethylenically unsaturated monomers and crosslinking agents in multiple stages to enhance absorption properties while maintaining low resin content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the water-absorbent resin content in an absorbent material is increased, then the absorption properties are improved, but the texture of the absorbent material is impaired
Solution Approach 1:
The patent changes the particle size parameter of the water-absorbent resin to a specific range (100 μm to 1 mm, preferably 150 μm to 500 μm) and controls the resin content within 5-50 mass% of the absorbent material. This parameter optimization allows achieving good absorption properties while maintaining acceptable texture, resolving the contradiction between absorption performance and material softness.
2Reliability
If the water-absorbent resin content in an absorbent material is increased, then the absorption properties are improved, but the uniform dispersion of the resin becomes difficult
Solution Approach 1:
The patent specifies a particle size range of 100 μm to 1 mm for the water-absorbent resin, which optimizes the balance between absorption capacity and dispersibility. This particle size control prevents agglomeration and ensures uniform distribution of the resin throughout the absorbent material, achieving both high absorption properties and uniform dispersion.
3Ease of operation
If the water-absorbent resin content in an absorbent material is decreased, then the texture of the absorbent material is maintained, but the absorption properties become unsatisfactory
Solution Approach 1:
The patent optimizes the water-absorbent resin content to be within 5-50 mass% of the absorbent material and controls particle size between 100 μm and 1 mm. This parameter optimization ensures that even at lower resin content levels, the absorption properties remain satisfactory while maintaining good texture characteristics.
4Ease of operation
If a water-absorbent resin with large particle size is used, then the wettability by water is improved, but the amount of backflow of absorbed liquid increases
Solution Approach 1:
The patent specifies a particle size range of 100 μm to 1 mm (preferably 150 μm to 500 μm) that optimizes the balance between wettability and backflow control. This intermediate particle size range provides sufficient surface area for good water wettability while maintaining adequate capillary structure to prevent excessive backflow of absorbed liquids.
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 reduces backflow even at low content, improving absorption properties and maintaining material texture, with controlled particle size and additives for enhanced performance in hygiene products.
Implementation Method 1
the water-absorbent resin having a dry-up index of 1.85 or more, the dry-up index being represented by the following equation (1): dry-up index=overall absorption capacity term α×water absorption rate term β
Implementation Method 2
a water-absorbent resin that is a crosslinked polymer of a water-soluble ethylenically unsaturated monomer
Data Source
AI summary
A water-absorbent resin that can reduce the amount of backflow of an absorbed liquid even when the water-absorbent resin is used at a low content in an absorbent material is provided. An absorbent article comprising an absorbent material containing the resin is also provided. The resin is a crosslinked polymer of a water-soluble ethylenically unsaturated monomer and has a dry-up index of 1.85 or more, as represented by equation (1):dry-up index=overall absorption capacity term α×water absorption rate term β (1)where the overall absorption capacity term α and the water absorption rate term β are determined according to equations (2) and (3):overallabsorptioncapacitytermα=(physiologicalsalineabsorptioncapacityunderaloadof2.07kPa-physiologicalsalineabsorptioncapacityunderaloadof4.82kPa)(physiologicalsalineabsorptioncapacity-physiologicalsalineretentioncapacity);(2)water absorption rate term β=dynamic water absorption rate/static water absorption rate (3).