Water-absorbing polymer color stability via sulfonate reducing agents
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current superabsorbent polymers used in sanitary products tend to discolor over time, especially in tropical climates, due to residual initiators and inhibitors from radical polymerization, compromising their color and odor stability without a significant impact on absorption properties.
Innovation Solution
A method for producing water-absorbing polymer structures that maintains improved color and odor stability by using conventional initiator systems, incorporating partial neutralization of monomers, and surface post-crosslinking with reducing agents like sulfonates, while ensuring absorption properties are not compromised.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional initiator systems (persulfates) are used in radical polymerization, then polymerization efficiency and absorption properties are improved, but color stability deteriorates due to discoloration from residual initiators and inhibitors
Solution Approach 1:
The patent removes harmful residual initiators and inhibitors from the polymer system through washing steps, extracting these discoloration-causing substances while preserving the polymer structure and absorption properties
Solution Approach 2:
The patent performs preliminary washing of the polymer particles after polymerization to remove residual initiators and inhibitors before they can cause discoloration during storage, preventing the color degradation problem in advance
2Stability of the object's composition
If sulfinates are used as initiator system to improve color stability, then color stability is improved, but polymerization efficiency and absorption properties deteriorate
Solution Approach 1:
The patent uses washing water as an intermediary medium to selectively remove harmful residual initiators and inhibitors from the polymer particles, separating the discoloration problem from the polymer structure without affecting absorption properties
Solution Approach 2:
The patent changes the chemical composition parameters of the polymer by removing specific substances (residual initiators and inhibitors) through controlled washing, thereby improving color stability while maintaining absorption capacity
3Quantity of substance
If superabsorbents are stored for long time in tropical climates, then absorption capacity is maintained, but color stability deteriorates rapidly due to high temperature and humidity
Solution Approach 1:
The patent converts the harmful effect of residual initiators and inhibitors into a benefit by deliberately removing them through washing, transforming the source of discoloration into a controlled removal step that prevents future color degradation while preserving absorption properties
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 method results in polymer structures with enhanced whiteness index and absorption capacity, maintaining stability under various climatic conditions without sacrificing absorption performance.
Implementation Method 1
treating the water-absorbing polymer structure with a reducing agent, in particular with sulfonates, salts of sulfonates
Implementation Method 2
water-insoluble, cross-linked polymers that are able to absorb large amounts of water, aqueous liquids, in particular body fluids, preferably urine or blood, while swelling and forming hydrogels
Data Source
AI summary
The present invention relates to a method for the production of water-absorbing polymer structures, having the following method steps: I) provision of an aqueous monomer solution containing a polymerizable, monoethylenically unsaturated monomer (a1) having an acid group, or a salt of said monomer, optionally a monoethylenically unsaturated monomer (a2) which can polymerize with the monomer (a1), and optionally a cross linking agent (a3), ii) radical polymerization of the aqueous monomer solution, giving a polymer gel, iii) optionally pulverization of the polymer gel, iv) drying the optionally pulverized polymer gel, giving a water-absorbing polymer structure, v) optionally milling and sieving the water-absorbing polymer structure, and vi) surface cross linking of the optionally milled and sieved water-absorbing polymer structure, wherein a reducing agent containing a sulfonate, a salt of a sulfonate, or a mixture of a sulfonate and a salt of a sulfonate is added to I) the water-absorbing polymer structure after carrying out method step iv), II) the water-absorbing polymer structure after carrying out method step v), III) the water-absorbing polymer structure after carrying out method step vi), IV) the aqueous monomer solution before or during method step ii), V) the polymer gel after carrying out method step ii), or VI) the optionally pulverized polymer gel after carrying out method step iii). The invention also relates to the water-absorbing polymer structure obtained by this method, water-absorbing polymer structures, a compound, a method for the production of a compound, the compound obtained by this method, chemical products such as foams, mold bodies, fibers, foils, films, cables, sealing materials, fluid-inhibiting hygiene articles, carriers for agents that regulate plant and fungus growth, packaging materials, soil additives, or building materials, and the use of water-absorbing polymer structures.