Superabsorbent Particle Agglomeration via Hydrophobic Solvent Dispersion
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Solution Overview
Problem
Current methods for agglomerating superabsorbent particles often result in compromised absorption capacity and rate, particularly for small polymer particles, which are difficult to handle and integrate effectively into products like diapers and agricultural applications.
Innovation Solution
A process involving the dispersion of polymer particles with a particle size of 250 μm or less in a hydrophobic organic solvent, followed by mixing with an aqueous monomer solution containing ethylenically unsaturated acid group-bearing monomers, crosslinkers, initiators, and water-soluble polymers, and subsequent polymerization, allowing for controlled centrifuge retention capacity and swelling rate optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If small polymer particles (250 μm or less) are directly used in superabsorbent products, then absorption capacity is maintained, but handling difficulty and poor integration into products increase
Solution Approach 1:
The patent combines multiple small polymer particles (250 μm or less) into larger agglomerates through a two-stage polymerization process. First, polymer particles are synthesized and separated at 250 μm or less. Then, these particles are dispersed in a hydrophobic organic solvent and mixed with an aqueous monomer solution containing crosslinkers and initiators. Upon polymerization, the small particles agglomerate into larger structures that maintain high absorption capacity while improving handling properties and product integration.
2Ease of operation
If conventional agglomeration methods are used, then particle size is increased for better handling, but absorption capacity and swelling rate decrease
Solution Approach 1:
The patent changes the chemical parameters of the system by introducing a hydrophobic organic solvent as a dispersion medium and using specific aqueous monomer solutions with controlled amounts of unneutralized monomer (0.5 to 80% by weight based on dispersed polymer particles). This parameter change enables agglomeration while preserving absorption capacity and swelling rate, overcoming the limitations of conventional agglomeration methods.
Solution Approach 2:
The patent creates a composite system involving polymer particles dispersed in a hydrophobic organic solvent phase, with an aqueous monomer solution phase containing crosslinkers and initiators. This composite approach allows the small polymer particles to be effectively agglomerated into larger structures that maintain their absorption properties while improving handling characteristics.
3Strength
If degree of crosslinking is increased to improve gel strength, then absorption under pressure improves, but absorption capacity decreases
Solution Approach 1:
The patent applies crosslinking locally at the particle surfaces during the agglomeration process, rather than uniformly throughout the entire gel structure. The aqueous monomer solution with crosslinkers and initiators is applied to the dispersed polymer particles, creating crosslinked regions primarily at the particle surfaces and interfaces. This local crosslinking enhances gel strength and absorption under pressure while preserving the internal structure's absorption 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
The process enhances the centrifuge retention capacity and swelling rate of superabsorbent particles, achieving improved absorption performance and particle size distribution, suitable for high-demand applications such as hygiene products and horticulture.
Implementation Method 1
polymer particles with a particle size of 250 μm or less are separated, the separated polymer particles are dispersed in a hydrophobic organic solvent
Implementation Method 2
the monomer solution is polymerized
Data Source
AI summary
The invention relates to a method for the agglomeration of super absorber particles, wherein polymer particles having a particle size of 250 µm or less are dispersed in a hydrophobic organic solvent, said dispersed polymer particles are mixed with an aqueous monomer solution which has an amount of non-neutralized monomer of 0.5 - 80 wt.%, with respect to the dispersed polymer particle, applied to the monomer solution, and the monomer solution is polymerised.