Super Absorbent Polymer Powder Reduction via Controlled Drying
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Solution Overview
Problem
The generation of fine powder during the pulverization of super absorbent polymers leads to increased process loads and environmental issues, while reducing the pulp content in hygienic materials requires high absorption capacity and rate, which is challenging to maintain without compromising physical properties.
Innovation Solution
A method involving crosslinking polymerization of water-soluble ethylenically unsaturated monomers with an internal crosslinking agent and controlled drying to reduce fine powder generation, including steps of forming a hydrogel polymer, drying to maintain 2-10 wt% water content, and pulverizing to achieve particles of 150-850 μm diameter, while adjusting the internal crosslinking agent amount to preserve physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the surface area of super absorbent polymer is increased to exhibit fast absorption rate, then the absorption rate is improved, but the structural strength becomes weak and fine powder is generated in the coarse pulverizing process
Solution Approach 1:
The patent changes the water content parameter from conventional low levels to specifically 2-10 wt% through controlled drying, which optimizes the balance between structural strength and absorption rate. This parameter adjustment prevents fine powder generation during pulverization while maintaining fast absorption capability.
Solution Approach 2:
The patent uses composite crosslinking by combining internal crosslinking agents (500-2500 ppmw) with the polymer matrix to create a composite structure that enhances structural strength while preserving surface area for fast absorption. The crosslinked network provides mechanical integrity without compromising the absorbent properties.
2Strength
If the internal crosslinking agent amount is increased to maintain structural strength, then the structural strength is improved, but the absorption capacity may be reduced
Solution Approach 1:
The patent optimizes the internal crosslinking agent concentration to a specific range of 500-2500 ppmw based on monomer weight, which balances structural strength and absorption capacity. This precise parameter control ensures sufficient mechanical integrity while maintaining high absorption performance.
Solution Approach 2:
The patent applies partial crosslinking rather than extensive crosslinking by using moderate amounts of internal crosslinking agents. This partial action provides enough structural strength to prevent fine powder generation while leaving sufficient absorption sites intact to maintain high absorption capacity.
3Ease of manufacture
If the water content is reduced to facilitate pulverization, then the pulverization process is improved, but the fine powder generation increases
Solution Approach 1:
The patent changes the water content parameter to an optimal range of 2-10 wt% through controlled drying, which facilitates pulverization while minimizing fine powder generation. This parameter optimization makes the pulverization process easier without creating environmental issues from excessive fine powder.
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
This method effectively reduces fine powder generation while maintaining excellent physical properties of super absorbent polymers, enhancing their absorption capacity and rate, thus addressing the challenges of process efficiency and environmental impact.
Implementation Method 1
performing crosslinking polymerization of a water-soluble ethylenically unsaturated monomer having an acidic group of which at least a part is neutralized, in the presence of an internal crosslinking agent and a polymerization initiator to form a hydrogel polymer containing a first crosslinked polymer
Implementation Method 2
drying the hydrogel polymer so that a water content of the polymer is 2 to 10 wt %
Implementation Method 3
pulverizing the dried polymer
Implementation Method 4
super absorbent polymer is a synthetic polymer material capable of absorbing moisture from about 500 to about 1,000 times its own weight
Data Source
AI summary
The method for preparing a super absorbent polymer according to the present disclosure has a feature that it is possible to reduce the generation of a fine powder during production of the super absorbent polymer while maintaining excellent physical properties of the super absorbent polymer, including centrifuge retention capacity (CRC) and vortex removal time.