Superabsorbent Polymer Porous Structure for Rapid Absorption
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Solution Overview
Problem
Current superabsorbent polymers used in thin diaper constructions suffer from inadequate absorption rates and leakage issues due to poor liquid transportation properties, leading to suboptimal performance in cellulose-free diaper designs.
Innovation Solution
A process for producing water-absorbing polymers involving the use of nonionic unsaturated polyether copolymers as surfactants and specific blowing agents, which are incorporated into the polymer network to enhance absorption capacity and permeability, resulting in a fine porous gel structure that improves liquid absorption and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If superabsorbent content is increased to reduce cellulose fiber content and thin diaper construction, then wear comfort and packaging costs are improved, but absorption rate and liquid transportation properties deteriorate
Solution Approach 1:
The patent applies porous materials by incorporating a blowing agent during polymerization to create a porous internal structure within the superabsorbent particles. This porous structure increases the surface area and creates channels for liquid penetration, thereby improving absorption rate and liquid transportation properties while maintaining the high superabsorbent content required for thin diaper constructions.
Solution Approach 2:
The patent applies parameter changes by modifying the polymerization process parameters, specifically by adding a blowing agent and controlling the polymerization conditions to achieve optimal porosity. This changes the physical structure of the polymer particles, enhancing their absorption kinetics and liquid distribution capabilities without compromising the reduced thickness of the diaper construction.
2Quantity of substance
If superabsorbent content is increased to reduce cellulose fiber content, then packaging and storage costs are reduced, but liquid transportation properties and leakage prevention deteriorate
Solution Approach 1:
The porous structure created by the blowing agent provides internal channels within the polymer particles that facilitate liquid transportation from the particle surface to the interior. This improves liquid distribution and prevents pooling at the surface, thereby enhancing leakage prevention while maintaining high superabsorbent content in the reduced-thickness diaper construction.
Solution Approach 2:
The blowing agent acts as an intermediary during polymerization, creating a porous matrix that mediates liquid transport within the polymer particles. This intermediate structure enables efficient liquid distribution throughout the high superabsorbent content material, ensuring reliable leakage prevention without requiring additional cellulose fibers.
3Productivity
If azo compounds are used as blowing agents to increase absorption rate, then absorption rate is improved, but particle dispersion and solution homogeneity deteriorate
Solution Approach 1:
The patent uses a solid blowing agent that decomposes during or after polymerization to release gas and create porosity. The blowing agent serves its function temporarily during the polymerization process and then decomposes, leaving no residual particles to cause dispersion issues. This approach maintains solution homogeneity while achieving the desired porous structure for improved absorption rate.
Solution Approach 2:
The blowing agent undergoes a phase transition from solid to gas during polymerization, creating bubbles that form the porous structure. This phase transition occurs in situ during the polymerization process, ensuring uniform distribution of pores throughout the polymer matrix without introducing separate solid particles that would compromise solution homogeneity.
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 process results in superabsorbent polymers with increased absorption rates and improved liquid distribution, minimizing leakage and enhancing the overall performance of thin diaper constructions by maintaining high permeability and surface tension, thus ensuring effective urine absorption and retention.
Implementation Method 1
0.01 to 5% by weight, preferably 0.02 to 2% by weight and more preferably 0.07 to 1% by weight of at least one surfactant from the group of the nonionic unsaturated polyether copolymers
Implementation Method 2
0.01 to 5% by weight, preferably 0.02 to 2% by weight and more preferably 0.07 to 1% by weight of a blowing agent having a particle size of 10 μm to 900 μm
Implementation Method 3
superabsorbent polymers with rapid absorption properties
Implementation Method 4
the ability of the hydrogel to conduct and distribute the liquid
Data Source
AI summary
The present invention relates to a process for producing a water-absorbing polymer, comprising the process steps of (i) mixing (α1) 0.1 to 99.999% by weight of polymerizable, ethylenically unsaturated monomers containing acid groups, or salts thereof, (α2) 0 to 70% by weight of polymerized, ethylenically unsaturated monomers copolymerizable with (α1), (α3) 0.001 to 10% by weight of one or more crosslinkers, where the sum of the weights (α1) to (α3) is 100% by weight, (ii) free-radical polymerization with crosslinking to form a water-insoluble, aqueous untreated hydrogel polymer, (iii) drying the hydrogel polymer, (iv) grinding and sieving the water-absorbing polymer to size, wherein the aqueous monomer solution, is admixed with 0.01 to 5% by weight of at least one surfactant and optionally 0.01 to 5% by weight of a blowing agent having a particle size of 10 μm to 900 μm, based on the water-absorbing polymer.