Water-absorbent resin particles with constrained swelling height
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Solution Overview
Problem
Absorbent articles face issues with liquid diffusion, where excess liquid can leak due to insufficient diffusion in the plane direction of the absorber, leading to surface flow and potential misuse or leakage.
Innovation Solution
The development of water-absorbent resin particles that suppress swelling in the vertical direction, allowing for effective liquid diffusion in the plane direction, achieved by controlling the swelling height and using specific polymerization methods such as reverse phase suspension polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water-absorbent resin particles are used with high absorption capacity, then the absorption capacity is improved, but the swelling in vertical direction increases causing liquid diffusion problem in plane direction
Solution Approach 1:
The patent applies parameter changes by controlling the swelling height of water-absorbent resin particles within a specific range (5mm to 15mm) to resolve the contradiction between absorption capacity and vertical swelling. By optimizing this physical parameter, the invention achieves both high absorption capacity and sufficient plane direction liquid diffusion.
Solution Approach 2:
The patent uses composite materials by combining water-absorbent resin particles with specific physical properties (controlled swelling height) with absorber structures. This composite approach enables the system to achieve both high absorption capacity and effective liquid distribution in the plane direction.
2Quantity of substance
If water-absorbent resin particles swell excessively in vertical direction, then absorption capacity increases, but liquid diffusion in plane direction is hindered leading to leakage
Solution Approach 1:
The patent resolves this contradiction by changing the physical parameter of swelling height to a controlled range (5mm to 15mm). This parameter optimization ensures that the resin particles maintain sufficient absorption capacity while preventing excessive vertical swelling that would block liquid diffusion in the plane direction, thereby ensuring reliable absorption performance without leakage.
3Reliability
If swelling height is reduced to improve liquid diffusion, then liquid diffusion is improved, but absorption capacity may be compromised
Solution Approach 1:
The patent resolves this contradiction by identifying and controlling the swelling height parameter within an optimal range (5mm to 15mm). This parameter optimization achieves the right balance: the swelling is sufficient to provide high absorption capacity but controlled enough to allow effective liquid diffusion in the plane direction, preventing both leakage and capacity loss.
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
This approach enables absorbent articles with improved liquid diffusion in the plane direction, reducing the risk of leakage and enhancing the absorption capacity while maintaining suitable water retention and absorption rates.
Implementation Method 1
When an absorbent article absorbs a liquid, if the liquid does not diffuse sufficiently and stays only in the vicinity of the liquid absorbing portion
Implementation Method 2
water-absorbent resin particles having a particle diameter of 0.3 mm to 0.7 mm and a swelling height of 7.0 mm to 9.2 mm
Data Source
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AI summary
An absorbent article 100 includes an absorber 10, the absorber 10 contains water-absorbent resin particles 10a, and a swelling height of the water-absorbent resin particles 10a measured by the following procedures (1) to (6) is 10 mm or less. (1) A container having a recess having a bottom area of 50 cm2 is disposed in a state where the recess is open in a vertical direction. (2) 1.00 g of water-absorbent resin particles are disposed in the recess. (3) A non-woven fabric is disposed on the water-absorbent resin particles in the recess. (4) A weight having a mass of 90 g is disposed on the non-woven fabric. (5) Physiological saline is supplied into the recess. (6) A movement distance in a vertical direction of the weight when 300 seconds have passed from the start of swelling of the water-absorbent resin particles is measured as the swelling height.