Cross-Linked Acrylamide Polymer With Low Discoloration and Residual Monomer
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Solution Overview
Problem
Existing cross-linked polymers using acrylamide as a raw material for salt-resistant water-absorbent resins face challenges in maintaining excellent water absorbency, reducing residual monomer content, and minimizing discoloration during long-term storage or use.
Innovation Solution
A cross-linked polymer with a transition metal content of 40 ppb or less, specifically copper, and a Yellowness Index of 60 or less, achieving a pure water retention capacity of 10 (g/g) or more, is produced through controlled polymerization processes to minimize discoloration and retain high water absorbency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cross-linked polymer is produced using conventional polymerization methods with copper catalysts, then polymerization efficiency is improved, but discoloration occurs during long-term storage and residual monomer content increases
Solution Approach 1:
The patent changes the chemical parameters of the polymerization system by replacing conventional copper-based catalysts with an organic peroxide initiator system. This parameter change eliminates the harmful discoloration effect while maintaining polymerization efficiency through optimized initiator concentration and reaction temperature control.
Solution Approach 2:
The patent employs a straightforward polymerization approach that uses readily available organic peroxide initiators rather than expensive specialized catalysts. The method accepts that some residual monomer will remain but keeps it at acceptable levels through controlled reaction conditions, avoiding the need for complex purification steps.
2Reliability
If cross-linked polymer is produced to maintain excellent water absorbency, then water retention capacity is improved, but residual monomer content increases and discoloration occurs
Solution Approach 1:
The patent optimizes the cross-linking parameters by controlling the ratio of cross-linking agent to monomer and adjusting polymerization temperature and time. These parameter changes enable achievement of high water absorbency (pure water retention capacity of 10 g/g or more) while minimizing residual monomer content and preventing discoloration through the use of organic peroxide initiators.
3Productivity
If polymerization is performed with high monomer concentration to improve productivity, then production efficiency is improved, but residual monomer content increases
Solution Approach 1:
The patent uses organic peroxide initiators that effectively initiate polymerization at high monomer concentrations, enabling high productivity while achieving complete conversion. The initiator system is designed to maintain active radical generation throughout the reaction, ensuring high monomer conversion even at elevated concentrations, thus minimizing residual monomer content.
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 polymer exhibits reduced discoloration and residual monomer content while maintaining excellent water absorbency, suitable for long-term use in water blocking materials.
Implementation Method 1
a method for producing a cross-linked polymer, the method including a step of polymerizing a monomer containing acrylamide
Implementation Method 2
cross-linked polymer that has a low monomer content after polymerization and is excellent in reducing discoloration after long-term storage or long-term use while maintaining excellent water absorbency
Data Source
AI summary
Provided herein are a cross-linked polymer with a low residual monomer content that is excellent in reducing discoloration after long-term storage or long-term use while maintaining excellent water absorbency and the like, and a method for producing the cross-linked polymer. The object is solved by a cross-linked polymer having a structural unit derived from acrylamide, the cross-linked polymer having: a content of transition metal other than iron of 40 ppb or less; Yellowness Index (YI) after an accelerated discoloration test of 60 or less; and a pure water retention capacity of 10 (g/g) or more.