Polychloroprene Dispersion Stripping via Controlled Solids Content
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Solution Overview
Problem
The existing processes for producing polychloroprene dispersions face issues with residual monomer content, as steam distillation leads to quick blockage of equipment due to coagulum formation, making it uneconomical and posing safety and handling challenges due to the flammability and toxicity of monomeric chloroprene.
Innovation Solution
A process involving emulsion polymerization with controlled solids content and a multistage stripper column to reduce chloroprene content to low ppm levels, using dilution with an aqueous phase and steam stripping, which prevents coagulum formation and allows for extended operation without equipment blockage, achieving a significantly lower residual monomer content in the polychloroprene dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If steam distillation is used to remove residual monomer from polychloroprene dispersion, then the chloroprene content is reduced, but the equipment becomes blocked by coagulum formation requiring shutdown and cleaning
Solution Approach 1:
The patent changes the operating parameters of the stripping process by controlling the polychloroprene concentration in the feed to the stripper column. By maintaining the concentration below a critical threshold (wsolid < 50%, preferably < 40%), the patent prevents coagulum formation while still achieving effective chloroprene removal. This parameter control resolves the contradiction between achieving low residual monomer content and maintaining continuous equipment operation.
Solution Approach 2:
The patent applies preliminary action by controlling the polymerization process to produce a polychloroprene dispersion with predetermined low concentration before feeding it to the stripper column. This pre-control of concentration ensures that the subsequent stripping operation will not encounter coagulum formation issues, allowing continuous operation while achieving the desired chloroprene removal.
2Productivity
If the proportion of polychloroprene in the dispersion is increased to improve productivity, then the solids content increases, but coagulum formation and equipment blockage occur more quickly
Solution Approach 1:
The patent identifies and controls the critical parameter of polychloroprene concentration in the dispersion fed to the stripper column. By establishing the optimal range (wsolid < 50%, preferably < 40%), the patent achieves a balance between productivity and manufacturability. This parameter optimization allows higher concentrations than previously thought possible without causing equipment blockage, thereby improving productivity while maintaining process economy.
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 enables uninterrupted operation of the stripper column for weeks, reduces the risk of blockages, improves occupational safety, and enhances the handling and safety of products based on polychloroprene dispersions by achieving low chloroprene content, thereby improving product handling and hygiene.
Implementation Method 1
a removal of chloroprene from the polychloroprene dispersion is carried out in a multistage and/or multitray stripper column
Implementation Method 2
a polymerization of chloroprene to polychloroprene is carried out in an emulsion
Data Source
AI summary
Disclosed are systems and methods for producing a polymer dispersion based on polychloroprene, comprising steps of polymerizing chloroprene to polychloroprene, adding the polycholoprene dispersion to a stripper column, and removing chloroprene from the polychloroprene dispersion.