Water-Absorbent Resin Particles for Thin Absorbent Articles
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Solution Overview
Problem
Conventional absorbent articles face challenges in achieving high absorption rates, liquid retention, and diffusion performance, particularly in replacing fibrous materials with water-absorbent resins to create thinner and more flexible sanitary products.
Innovation Solution
Development of an absorbent article with a primary aqueous-liquid-absorbing agent comprising water-absorbent resin particles obtained by polymerizing a water-soluble ethylenically unsaturated monomer with an internal-crosslinking agent, exhibiting a water absorption capacity of 5 to 25 g/g and saline flow conductivity of not less than 1216 x 10^-7 cm^3/s/g, and optionally incorporating a secondary aqueous-liquid-absorbing agent with lower saline flow conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If water-absorbent resins are used to replace fibrous materials to create thinner absorbent articles, then the thickness is reduced and flexibility is improved, but the performance of rapidly absorbing and diffusing aqueous liquids deteriorates
Solution Approach 1:
The invention changes the physical and chemical parameters of the water-absorbent resin by controlling the crosslinking degree and molecular structure. The resin is designed with a specific crosslinking density (0.1-10 mmol/g) and molecular weight distribution to achieve both thin profile and rapid absorption kinetics, resolving the contradiction between reduced thickness and maintained absorption speed
Solution Approach 2:
The invention uses composite material structure by combining water-absorbent resin particles with specific fibrous materials in optimized ratios. The composite absorbent core integrates resin particles (providing high capacity) with selected fibers (providing rapid wicking and diffusion), achieving both thinness and rapid liquid acquisition/diffusion performance
2Volume of moving object
If the ratio of water-absorbent resins to fibrous material is increased to achieve thinner materials, then the thickness and flexibility are improved, but the liquid retention performance deteriorates
Solution Approach 1:
The invention optimizes the crosslinking parameters of the water-absorbent resin to achieve a balanced gel structure. By controlling the crosslinking degree within specific ranges (0.1-10 mmol/g) and adjusting the molecular weight distribution, the resin maintains both high liquid capacity and effective retention, preventing leakage even at reduced thickness
Solution Approach 2:
The invention applies local quality differentiation by creating zones with different resin-to-fiber ratios within the absorbent core. High-resin zones provide maximum capacity and thinness, while strategically placed fiber-rich zones provide rapid wicking and retention barriers, achieving overall thin profile with reliable liquid retention across different regions
3Ease of operation
If fibrous materials are replaced with water-absorbent resins to increase resin ratio, then the flexibility and thinness are improved, but the performance of rapidly acquiring and diffusing aqueous liquid deteriorates
Solution Approach 1:
The invention employs composite material architecture combining water-absorbent resin particles with hydrophilic fibrous materials in optimized configurations. The fiber network provides capillary channels for rapid liquid acquisition and diffusion, while the resin particles provide high absorption capacity and flexibility, achieving synergistic performance that neither material could achieve alone
Solution Approach 2:
The invention segments the absorbent core into functional zones: acquisition layers with fiber-resin mixtures for rapid liquid uptake and distribution, and storage layers with higher resin content for capacity and flexibility. This segmentation allows each zone to be optimized for its specific function, maintaining rapid acquisition performance while achieving thin overall profile
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 solution enables the creation of thinner, more flexible absorbent articles that rapidly absorb and temporarily retain aqueous liquids, mimicking the performance of fibrous materials while reducing cellulose fiber content, thereby enhancing the overall absorption and retention capabilities.
Implementation Method 1
water-absorbent resin particles obtained by a process including the step of polymerizing a water-soluble ethylenically unsaturated monomer having a carboxyl group
Implementation Method 2
exhibiting a water absorption capacity (CRC) of 5 to 25 g/g and a saline flow conductivity (SFC) of not less than 1216 x 10^-7
Implementation Method 3
the resin particles being internally cross-linked with the selected internal-crosslinking agent described herein
Implementation Method 4
surface-crosslinked, whereby the primary aqueous-liquid-absorbing agent exhibits a water absorption capacity
Implementation Method 5
a performance of diffusing the aqueous liquid after having absorbed it
Implementation Method 6
exhibiting a water absorption capacity (CRC) of 5 to 25 g/g and a saline flow conductivity (SFC)
Data Source
Figure 1~2
Figure 3~4
AI summary
An absorbent article comprising an absorbent core, which comprises a primary aqueous-liquid-absorbing agent that contains water-absorbent resin particles, wherein the water-absorbent resin particles are obtained by a process including the step of polymerizing a water-soluble ethylenically unsaturated monomer having a carboxyl group, in the presence of an internal-crosslinking agent having at least four functional groups each capable of forming a covalent bond with a carboxyl group to thereby obtain a hydropolymer that is internally cross-linked and surface-crosslinked, the primary aqueous-liquid-absorbing agent being characterized by exhibiting a water absorption capacity (CRC) of 5 to 25 g/g and a saline flow conductivity (SFC) of not less than 1216 xl?~7cm3 s/g.