Superabsorbent Polymer Particle Distribution for Rapid Liquid Acquisition
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Solution Overview
Problem
Absorbent articles with superabsorbent polymer particles face challenges in achieving fast liquid acquisition, particularly at the initial contact with liquid, leading to potential leakage due to poor permeability and gel blocking, despite high Free Swell Rate (FSR) and Saline Flow Conductivity (SFC) values.
Innovation Solution
The absorbent article is designed with a structure comprising at least 90% superabsorbent polymer particles, optimized for a time to reach 20 g/g uptake of less than 440 seconds and enhanced permeability, featuring a thermoplastic adhesive material to immobilize particles and improve liquid distribution, reducing the risk of leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If superabsorbent polymer particles with high Free Swell Rate (FSR) and high Saline Flow Conductivity (SFC) values are used, then absorption speed and permeability are improved, but fast acquisition time at initial liquid contact is not guaranteed
Solution Approach 1:
The patent changes the measurement parameter from equilibrium-based SFC to dynamic T20 acquisition time, capturing the initial absorption phase behavior. This parameter change reveals that high FSR and SFC do not correlate with fast initial acquisition, leading to optimized particle selections that specifically target first-gush performance
Solution Approach 2:
The patent applies preliminary action by pre-swelling the superabsorbent polymer particles before use. This preliminary swelling action prepares the particles to rapidly acquire liquid at initial contact, addressing the slow first-gush acquisition problem while maintaining the benefits of high FSR and SFC particles
2Productivity
If superabsorbent polymer particles absorb liquid quickly, then absorption capacity is improved, but gel blocking occurs and permeability decreases
Solution Approach 1:
The patent applies dynamics by measuring permeability under dynamic loading conditions rather than static equilibrium. The T20 measurement captures permeability behavior during the active absorption phase, revealing that particles maintaining high permeability during dynamic loading can achieve both high absorption capacity and sustained liquid flow without gel blocking
Solution Approach 2:
The patent utilizes porous materials by selecting superabsorbent polymer particles with optimized pore structures that maintain open channels during swelling. This porous structure allows liquid to penetrate deeply and rapidly while preventing gel blocking, achieving both high absorption capacity and sustained permeability
3Quantity of substance
If absorbent core thickness is increased to improve absorption capacity, then liquid storage is improved, but liquid acquisition time increases
Solution Approach 1:
The patent applies local quality by creating a gradient in superabsorbent polymer particle distribution within the absorbent core. The region near the liquid entry point contains particles with optimized T20 characteristics for rapid initial acquisition, while deeper regions provide additional capacity. This local optimization ensures fast liquid capture without sacrificing overall absorption capacity
Solution Approach 2:
The patent segments the absorbent core into functional zones with different particle characteristics. The top layer contains particles optimized for rapid liquid acquisition (low T20), while lower layers provide bulk absorption capacity. This segmentation allows the core to simultaneously achieve fast liquid capture and high storage capacity
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 configuration results in improved absorption properties and reduced leakage, especially during the first gush, by ensuring fast and efficient liquid acquisition and distribution throughout the absorbent structure.
Implementation Method 1
Superabsorbent polymer particles are able to absorb liquid and swell when entering into contact with liquid exudates
Implementation Method 2
The liquid exudates can not or only slowly reach underneath layers of superabsorbent polymer particles disposed in the core
Data Source
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AI summary
An absorbent article such as disposable diaper, training pant, and adult incontinence undergarment comprising an absorbent structure comprising superabsorbent polymer particles, the article being able to absorb and contain body exudates and having improved absorption properties and therefore being able to reduce leakage, especially at the first gush, i. e. when the article starts to be wetted.