Branched Rubber Latex via Silane Coupling for Low Viscosity
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Solution Overview
Problem
There is a need for improved methods to produce latex and latex articles with enhanced properties using new block copolymers and homopolymers, and to increase the productivity of the processes involved in their formation.
Innovation Solution
A process involving the use of branched block copolymers and polyisoprene homopolymers, formed using a multifunctional coupling agent, which are then emulsified to create rubber latex with specific molecular weight ranges and coupling efficiencies, resulting in improved physical and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional linear polymers are used to produce rubber latex, then the polymer structure is simple and easy to manufacture, but the viscosity is high and productivity is limited
Solution Approach 1:
The patent applies segmentation by dividing the polymer structure into multiple blocks (A and B blocks) connected in a branched architecture rather than a linear chain. This segmentation of the polymer backbone reduces entanglement and decreases viscosity, enabling higher throughput without equipment upgrades while maintaining structural integrity through the coupled block design.
2Productivity
If branched block copolymers with complex structures are synthesized, then productivity and throughput are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent uses a silane coupling agent as an intermediary to facilitate the formation of branched block copolymers. The coupling agent mediates between polymer blocks, enabling controlled branching through siloxane bonds. This intermediary approach simplifies the manufacturing process by providing a systematic method to create complex branched structures without requiring overly complicated synthesis equipment or procedures.
3Strength
If higher molecular weight polymers are used to improve mechanical properties, then tensile strength and tear resistance are enhanced, but viscosity increases and processing becomes difficult
Solution Approach 1:
The patent applies segmentation by creating branched architectures with multiple A and B blocks coupled through silane linkages. This segmented structure allows the polymer to achieve high molecular weight and enhanced tensile strength while the branched configuration reduces chain entanglement, thereby maintaining lower viscosity and improving processability compared to linear polymers of equivalent molecular weight.
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 yields latex with reduced viscosity, allowing for higher throughput without equipment upgrades and produces latex articles with superior tensile strength, elongation, and tear resistance, enhancing manufacturing efficiency and product quality.
Implementation Method 1
The reactive polymer chain, having a carbanionic chain end, reacts with the 2 silicon centers of the coupling agent (I) to form coupled block copolymers and coupled homopolymers
Implementation Method 2
emulsifying the rubber cement to form the rubber latex
Data Source
AI summary
The disclosure relates to rubber latex formed from any of: branched block copolymers derived from alkenyl aromatic hydrocarbon—1,3-diene monomer system, and branched polyisoprene homopolymers derived from isoprene. The polymers in embodiments are obtained by polymerization in the presence of an anionic initiator; at a temperature from 0° C. to 100° C.; followed by coupling with a multifunctional coupling agent of formula (R1O)3Si—Y—Si(OR2)3, wherein R1 and R2 are independently C1-C6 alkyl groups; and Y is a C2-C8 alkylene group. The polymers are obtained as rubber cements having high solids content and low zero shear viscosities. The rubber cements are valuable for making latices for further applications.