Curable polymer latex compositions for the manufacture of rubber articles
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Solution Overview
Problem
Current methods for producing thin film rubber articles, such as gloves, face challenges in achieving a balance between reduced film thickness for cost efficiency and waste reduction while maintaining mechanical properties like tensile strength, elongation at break, and softness, without degrading skin compatibility or introducing undesirable odors and colors.
Innovation Solution
A curable polymer latex composition is developed through free-radical emulsion polymerization of a monomer mixture comprising conjugated diene and ethylenically unsaturated nitrile, matured in the presence of thiocarbonyl-functional compounds, which enhances softness and tensile strength without compromising other essential properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the film thickness is reduced to lower raw material consumption and production costs, then the amount of waste material is reduced, but the mechanical properties such as tensile strength and elongation at break deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and molecular structure of the polymer latex through controlled free-radical emulsion polymerization. By adjusting monomer ratios, initiator types, and polymerization conditions, the invention achieves optimized mechanical properties in thin films without compromising tensile strength and elongation at break, thereby enabling reduced film thickness while maintaining performance requirements
Solution Approach 2:
The invention uses composite materials by combining specific monomers (conjugated diene and ethylenically unsaturated nitrile) in controlled proportions to create a copolymer latex with enhanced mechanical properties. This composite approach allows the thin film to achieve adequate tensile strength and elongation at break through the synergistic effects of different monomer units, enabling reduced material consumption while maintaining structural integrity
2Loss of substance
If the film thickness is reduced, then production costs are lowered, but the softness and tactility of the rubber article deteriorate
Solution Approach 1:
The patent applies parameter changes by carefully controlling the polymer latex composition, including monomer ratios, molecular weight distribution, and cross-linking density. These parameter optimizations enable thin films to maintain adequate softness and tactility for comfortable wearing properties while minimizing raw material consumption and production costs
3Object-affected harmful factors
If synthetic polymer latex is used instead of natural rubber latex, then skin compatibility is improved by eliminating latex proteins, but the softness and comfortable feel deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the synthetic polymer latex composition through controlled free-radical emulsion polymerization of conjugated diene and ethylenically unsaturated nitrile monomers. By adjusting polymerization parameters, molecular weight, and compositional ratios, the invention achieves a balance between skin compatibility (eliminating latex proteins) and softness, enabling synthetic gloves to provide comfortable wearing properties while maintaining hypoallergenic characteristics
Solution Approach 2:
The invention uses composite materials by creating a copolymer latex from conjugated diene and ethylenically unsaturated nitrile monomers in specific proportions. This composite structure provides both the skin compatibility of synthetic polymers (no latex proteins) and the softness required for comfortable wear, resolving the contradiction between health safety and comfort
4Strength
If cross-linking agents are added to improve mechanical properties, then tensile strength is enhanced, but undesirable odors and color changes are introduced
Solution Approach 1:
The patent applies parameter changes by optimizing the polymer latex composition and molecular structure through controlled free-radical emulsion polymerization. By adjusting monomer ratios, initiator types, and polymerization conditions, the invention reduces the need for extensive cross-linking, thereby minimizing undesirable odors and color changes while maintaining adequate tensile strength through inherent polymer properties
Solution Approach 2:
The invention minimizes the use of cross-linking agents and other chemical additives by designing a polymer latex composition that achieves adequate mechanical properties through controlled polymerization. This approach reduces the introduction of harmful factors such as undesirable odors and color changes, making the rubber articles more suitable for applications where odor and appearance stability are critical
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 approach results in rubber articles with improved mechanical properties, including enhanced softness and tensile strength, while maintaining aging stability and avoiding undesirable odors or color changes, thus optimizing film thickness and production efficiency.
Implementation Method 1
free-radical emulsion polymerization of a monomer mixture comprising conjugated diene and ethylenically unsaturated nitrile
Implementation Method 2
matured in the presence of thiocarbonyl-functional compounds, which enhances softness and tensile strength
Data Source
AI summary
A curable polymer latex composition obtainable by:(a) subjecting a monomer mixture comprisingi. at least one conjugated diene;ii. at least one ethylenically unsaturated nitrile;iii. optionally at least one ethylenically unsaturated acid;iv. optionally at least one further ethylenically unsaturated compound different from any of the compounds (i)-(iii);to free-radical emulsion polymerization in an aqueous reaction medium to form a raw polymer latex; and(b) allowing the obtained raw latex to mature in the presence of at least one thiocarbonyl-functional compound, wherein the at least one thiocarbonyl-functional compound is present in an amount of at least 0.05 wt.-%, based on the total amount of monomers subjected to free-radical emulsion polymerization in step (a), and(c) optionally compounding the matured polymer latex with one or more cross-linking agent. Methods for making such curable polymer latex composition or rubber articles made therefrom, respectively.