Butyl Rubber Particle Isolation Using LCST Anti-Agglomerants
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Solution Overview
Problem
Current processes for producing butyl rubber particles in aqueous media face challenges with agglomeration and chemical interactions with rubber cure systems, leading to suboptimal cure characteristics and contamination issues due to the use of fatty acid salts like calcium and zinc stearates as anti-agglomerants.
Innovation Solution
A process involving polymerization of isoolefins and multiolefins in an organic diluent, followed by contact with an aqueous medium containing a Low Critical Solution Temperature (LCST) compound to form a slurry with reduced levels of non-LCST compounds, which includes using LCST compounds like methyl cellulose to control agglomeration and minimize metal ion contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fatty acid salts (calcium stearate, zinc stearate) are used as anti-agglomerants in butyl rubber particle production, then particle suspension and anti-agglomeration are improved, but chemical interactions with rubber cure systems occur leading to suboptimal cure characteristics and contamination
Solution Approach 1:
The patent changes the chemical composition parameter of the aqueous medium by replacing traditional fatty acid salt anti-agglomerants with alternative compounds such as polyacrylamide, polyvinyl alcohol, or carboxymethyl cellulose. This parameter change maintains the anti-agglomeration function while eliminating harmful chemical interactions with the rubber cure system, thereby resolving the contradiction between particle suspension stability and chemical contamination.
2Reliability
If high levels of anti-agglomerants are used to prevent agglomeration during processing, then particle suspension is improved, but product purity and quality are reduced due to contamination
Solution Approach 1:
The patent employs anti-agglomerant compounds that can be easily removed or decomposed during the processing sequence. These alternatives to fatty acid salts allow for effective anti-agglomeration during particle formation and suspension, but can be subsequently eliminated through filtration or decomposition steps, thus maintaining product purity while ensuring particle stability during processing.
3Ease of manufacture
If traditional anti-agglomerant processes are used, then particle formation is achieved, but additional processing steps and complexity are required to remove contamination and ensure purity
Solution Approach 1:
The patent employs anti-agglomerant compounds that are inherently compatible with the rubber matrix and do not require additional removal steps. These alternatives to traditional fatty acid salts perform the anti-agglomeration function and remain benign in the final product, thereby simplifying the overall processing sequence by eliminating the need for additional purification or removal steps while maintaining ease of particle formation.
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
This approach results in high-purity butyl rubber particles with improved cure characteristics and reduced contamination, allowing for efficient separation and processing without the need for high levels of anti-agglomerants, thereby enhancing the quality and purity of the final product.
Implementation Method 1
contacting the medium obtained in step b) with an aqueous medium comprising at least one LCST compound having a cloud point of 0 to 100°C
Data Source
AI summary
The invention relates to an efficient process for the preparation and isolation of rubber particles formed in aqueous media and highly pure rubbers obtained thereby. The invention further relates to copolymer products comprising the same or derived therefrom.