Water-absorbing polymer particles with tannin coating for odor control
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Solution Overview
Problem
Existing methods for producing odor-inhibiting, water-absorbing polymer particles face challenges in achieving effective odor inhibition while minimizing undesirable discoloration, primarily due to trace iron ions present in the production process.
Innovation Solution
A method involving the neutralization of ethylenically unsaturated acid-group-carrying monomers with a base containing less than 0.0005% iron ions, followed by polymerization with an initiator free of iron ions, and subsequent coating with condensed and/or hydrolyzable tannins, while using stainless steel or polymeric materials to minimize iron contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional base materials and equipment are used in the neutralization process, then production cost is reduced, but iron ion contamination increases causing discoloration
Solution Approach 1:
The patent specifies stringent parameter limits for iron ion content in base materials (less than 0.0005% by weight) and in polymer particles (less than 0.01% by weight). This parameter change approach transforms the manufacturing process by requiring ultra-low iron content materials and equipment, thereby preventing discoloration while maintaining production feasibility through defined specifications.
Solution Approach 2:
The patent introduces stainless steel equipment and polymeric material linings as intermediary elements between the base material and the polymerization process. These intermediaries prevent iron ion contamination by creating a barrier that excludes conventional iron-containing equipment, thus solving the discoloration problem without completely redesigning the entire manufacturing system.
2Object-generated harmful factors
If iron-containing catalysts or initiators are used in polymerization, then reaction efficiency is improved, but odor inhibition effectiveness decreases
Solution Approach 1:
The patent extracts and removes iron ions from the polymerization process by specifying that initiators must have iron ion content of less than 0.1% by weight. This extraction principle eliminates the harmful interaction between iron ions and tannin coating that would otherwise reduce odor inhibition effectiveness, while maintaining polymerization efficiency through alternative initiator systems.
Solution Approach 2:
The patent employs composite material strategies by combining iron-free or low-iron initiators with tannin coating on polymer particles. This composite approach creates a system where the polymer matrix and surface coating work together synergistically to provide both structural integrity and odor inhibition without the interfering presence of iron ions.
3Quantity of substance
If high iron ion content base is used for neutralization, then material cost is reduced, but tannin coating effectiveness is compromised
Solution Approach 1:
The patent fundamentally changes the purity parameter of base materials by specifying iron ion content must be less than 0.0005% by weight. This parameter change ensures that the base material, while potentially more expensive, provides reliable odor inhibition by not interfering with the tannin coating's function. The strict parameter control makes the odor inhibition reliability predictable and consistent.
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 results in water-absorbing polymer particles with enhanced odor inhibition and reduced discoloration tendency, maintaining a low iron ion content and improved performance characteristics.
Implementation Method 1
the neutralization of at least one ethylenically unsaturated, acid-group-carrying monomer with a base to a degree of neutralization of 40 to 70 mol%
Implementation Method 2
polymerisation of the neutralized monomer in the presence of at least one crosslinking agent and at least one initiator
Implementation Method 3
the polymer particles are coated with 0.01 to 1% by weight of at least one condensed and/or one hydrolyzable tannin
Data Source
AI summary
The invention relates to a method for producing odor-inhibiting, water-absorbing polymer particles based on ethylenically unsaturated monomers carrying acid groups, wherein 40 to 70 mol% of the acid groups are neutralized and the polymer particles are coated with a condensed tannin or a tannin that can be hydrolyzed.