Polymer Latex Chain-Transfer Sequencing for Higher Strength
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Solution Overview
Problem
Existing polymer latexes used in paper and carpet backing applications lack sufficient mechanical properties, such as high elongation at break and tensile strength, which are essential for effective binding and resistance to moisture and ink splitting forces during printing processes.
Innovation Solution
A polymer latex is produced by combining hydroperoxide and sulfur-containing chain transfer agents during the polymerization of ethylenically unsaturated aromatic and conjugated diene monomers, where the sulfur-containing agent is added after a significant portion of the hydroperoxide has been introduced, resulting in a polymer with improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polymerization methods using single chain transfer agents are used, then the polymerization process is simple, but the mechanical properties (elongation at break and tensile strength) are insufficient
Solution Approach 1:
The patent combines two different chain transfer agents (hydroperoxide and sulfur-containing compounds) in a single polymerization process. The hydroperoxide chain transfer agent is added first to initiate polymerization and control molecular weight, followed by the sulfur-containing chain transfer agent to further modify polymer structure and enhance mechanical properties. This merging of multiple agents achieves superior elongation at break and tensile strength that cannot be obtained with a single agent alone.
2Strength
If polymer latex with high tensile strength is produced, then binding strength in paper coating is improved, but the flexibility for ease of installation may be reduced
Solution Approach 1:
The patent optimizes the concentration ratios and addition sequences of hydroperoxide and sulfur-containing chain transfer agents to achieve the desired balance between strength and flexibility. By carefully controlling the amounts of each agent and their addition timing, the polymer latex attains high tensile strength for binding while maintaining sufficient flexibility for carpet installation and pattern matching.
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 latex exhibits superior binding effects with high elongation and tensile strength, enhancing the performance in paper coatings, carpet backing, and fiber fabric pre-impregnation processes by providing better resistance to ink splitting and moisture retention.
Implementation Method 1
polymerizing one or more ethylenically unsaturated aromatic monomers and one or more conjugated diene monomers in the presence of hydroperoxide chain transfer agent and sulfur-containing chain transfer agent
Implementation Method 2
the combination of a hydroperoxide chain transfer agent and a sulfur-containing chain transfer agent allows the polymerization to provide a polymer latex with improved mechanical properties
Data Source
Figure 1
AI summary
The present invention relates to a process for preparing a polymer latex comprising polymerizing one or more ethylenically unsaturated aromatic monomers and one or more conjugated diene monomers in the presence of hydroperoxide chain transfer agent and sulfur-containing chain transfer agent, wherein the sulfur-containing chain transfer agent is added after the hydroperoxide chain transfer agent. It further relates to the polymer latex thus obtained, to a composition comprising the polymer latex and to the use of the polymer latex or polymer latex composition in a carpet backing, paper coating, or fiber fabric pre-impregnation process.