Superabsorbent Polymer with Low Aspect Ratio Particles
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Solution Overview
Problem
Existing superabsorbent polymers face challenges in achieving high absorption rates and liquid permeability while maintaining excellent absorption performances, particularly in thinner diapers where uneven surface crosslinking and particle shape issues lead to compromised physical properties.
Innovation Solution
A superabsorbent polymer with a base polymer powder and surface crosslinked layer, formed using water-soluble ethylene-based unsaturated monomers and a surface crosslinking agent, featuring a low aspect ratio and high saline flow conductivity, achieved through foaming polymerization and controlled surface crosslinking with a surface tension of 30-50 mN/m.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a foaming agent is used to create a porous structure for high absorption rate, then the absorption rate improves, but the particle shape becomes uneven leading to poor manufacturing precision
Solution Approach 1:
The invention changes the physical-chemical parameters of the polymerization process by controlling the foaming agent concentration (0.01-1.0 parts by weight) and using specific crosslinking agents to achieve uniform particle shapes with aspect ratios of 0.4 or less while maintaining the porous structure necessary for high absorption rate
Solution Approach 2:
The invention creates a composite structure within the polymer particles by combining the porous foam structure with a controlled crosslinking network, achieving both high absorption rate through porosity and uniform particle shape through the composite material design
2Strength
If surface crosslinking is performed to improve liquid permeability and gel strength, then liquid permeability improves, but uneven crosslinking occurs on irregular particles leading to deteriorated physical properties
Solution Approach 1:
The invention performs preliminary action by creating uniform spherical particles with controlled aspect ratios before surface crosslinking, ensuring that subsequent crosslinking occurs evenly across all particle surfaces and preventing the uneven crosslinking that would occur on irregularly shaped particles
Solution Approach 2:
The invention changes the particle shape parameters to achieve aspect ratios of 0.4 or less, which provides a uniform geometric foundation for even surface crosslinking, thereby achieving homogeneous crosslinking and improved gel strength
3Quantity of substance
If the proportion of superabsorbent polymer is increased to compensate for reduced fibrous materials in thinner diapers, then absorption capacity improves, but absorption rate must be significantly higher to prevent leakage
Solution Approach 1:
The invention uses porous materials by incorporating a foaming agent during polymerization to create an internal porous structure within the superabsorbent polymer particles, which significantly increases the absorption rate by providing more pathways for rapid liquid penetration while maintaining high absorption capacity
Solution Approach 2:
The invention creates a composite structure combining the porous foam matrix with crosslinked polymer networks, achieving both high absorption capacity through the polymer gel structure and high absorption rate through the porous architecture
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 enhances absorption rate, liquid permeability, and absorbency under pressure, ensuring effective urine retention and reduced leakage in sanitary products, while maintaining excellent basic absorption performances.
Implementation Method 1
the superabsorbent polymer needs to retain in its shape, thereby maintaining voids between particles. This is because voids between the particles act as a flow path to ensure excellent liquid permeability
Implementation Method 2
in order to provide a superabsorbent polymer exhibiting more improved liquid permeability and other excellent physical properties, such a superabsorbent polymer needs to exhibit a higher gel strength through surface crosslinking
Implementation Method 3
superabsorbent polymers are required to exhibit high absorbency with respect to water, etc., must not release absorbed water even under an external pressure
Data Source
Figure 1
AI summary
Provided are a superabsorbent polymer exhibiting more improved absorption rate and liquid permeability as well as excellent basic absorption performance, and a preparation method thereof. The superabsorbent polymer includes a base polymer powder including a crosslinked polymer of watersoluble ethylene-based unsaturated monomers having acidic groups which are at least partially neutralized; and a surface crosslinked layer which is formed on the base polymer powder and in which the base polymer powder is additionally crosslinked via a surface crosslinking agent, wherein the superabsorbent polymer includes 10% by number or more of superabsorbent polymer particles each particle having an aspect ratio of less than 0.5, the aspect ratio defined as the shortest diameter/the longest diameter of the superabsorbent polymer particle, and has SFC in a predetermined range.