Super Absorbent Polymer with Surface Crosslinked Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current super absorbent polymers used in hygienic materials like diapers face challenges in achieving high absorption rates and liquid permeability while maintaining excellent basic absorption performance, particularly in thinner products.
Innovation Solution
A super absorbent polymer is developed with a base polymer powder and a surface crosslinked layer, using specific internal and surface crosslinking agents, which is produced through controlled polymerization and gel pulverization processes to achieve enhanced gel strength, absorption rate, and liquid permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gel pulverization is performed to produce powder or particle form super absorbent polymer, then the polymer can be used in hygienic materials, but the physical properties including absorption rate and liquid permeability are significantly affected and often deteriorated
Solution Approach 1:
The patent applies preliminary action by optimizing the polymerization conditions before pulverization to create a hydrogel with controlled gel strength and porous structure. By pre-forming the polymer network with appropriate crosslinking density and pore structure during polymerization, the subsequent pulverization process preserves more of the absorption properties, resulting in higher absorption rates while maintaining manufacturability
Solution Approach 2:
The patent utilizes parameter changes by systematically adjusting polymerization parameters including monomer composition, crosslinking agent concentration, polymerization temperature, and pH conditions. These parameter optimizations create a hydrogel precursor with specific gel strength and pore structure that withstands pulverization better, maintaining absorption rate and liquid permeability in the final powdered product
2Quantity of substance
If the proportion of absorbent polymer is increased to meet thin diaper requirements, then basic absorption performance improves, but absorption rate and liquid permeability become insufficient
Solution Approach 1:
The patent applies local quality by creating a non-uniform porous structure within the hydrogel particles, with higher porosity and larger pore sizes in specific regions. This localized structural optimization allows rapid liquid penetration and absorption while maintaining high overall absorption capacity, enabling thin diaper designs to achieve both speed and capacity requirements
Solution Approach 2:
The patent employs composite materials by combining multiple monomers and crosslinking agents with different functional properties. The composite polymer network integrates components that provide high absorption capacity with components that enhance liquid permeability and absorption rate, achieving superior overall performance that satisfies thin diaper requirements
3Speed
If gel grinding energy is increased to achieve high absorption rate, then absorption rate improves, but absorption under pressure is lowered
Solution Approach 1:
The patent applies segmentation by creating a hierarchical porous structure with multiple pore size distributions within the hydrogel particles. This segmented pore architecture allows rapid liquid uptake through larger pores (improving absorption rate) while maintaining the structural integrity needed for pressure absorption through smaller pores and crosslinked networks, thus resolving the contradiction between speed and strength
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 resulting super absorbent polymer exhibits improved absorption rate and liquid permeability while maintaining excellent basic absorption performance, making it suitable for thinner hygienic materials like diapers.
Implementation Method 1
Super absorbent polymer (SAP) is a synthetic polymer material capable of absorbing moisture from about 500 to about 1,000 times its own weight
Implementation Method 2
it should well retain the shape even in a state where the volume is expanded (swelled) by absorbing water, and thereby exhibit excellent liquid permeability
Implementation Method 3
radical polymerization while cross-linking, in order to form a hydrogel polymer
Implementation Method 4
performing crosslinking polymerization of a water-soluble ethylenically unsaturated monomer having at least partially neutralized acidic groups in the presence of an internal crosslinking agent to form a hydrogel polymer
Data Source
AI summary
The present invention relates to a super absorbent polymer exhibiting more improved absorption rate and liquid permeability, as well as having excellent basic absorption performance, and a method for producing the same. The super absorbent polymer comprises: a base polymer powder including a first crosslinked polymer of a water-soluble ethylenically unsaturated monomer having at least partially neutralized acidic groups; and a surface crosslinked layer formed on the base polymer powder and including a second crosslinked polymer in which the first crosslinked polymer is further crosslinked via a surface crosslinking agent, wherein the super absorbent polymer has: a fixed height absorption (FHA) (20 cm) for a physiological saline solution (0.9 wt% aqueous sodium chloride solution) of 22.5 g/g to 29 g/g, a saline flow conductivity (SFC) for a physiological saline solution (0.685 wt% aqueous sodium chloride solution) of 35 (·10-7 cm3·s/g) or more, and T-20 of 180 seconds or less which indicates the time required for absorbing 1 g of the super absorbent polymer to 20 g of aqueous solution of 0.9 wt% sodium chloride and 0.01 wt% alcohol ethoxylate having 12 to 14 carbon atoms under pressure of 0.3 psi.