Polychloroprene Dispersion Stripping to Prevent Coagulum
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Solution Overview
Problem
The existing methods for producing polychloroprene dispersions face challenges in reducing the monomeric chloroprene content due to the formation of coagulum in steam distillation columns, leading to operational inefficiencies and safety concerns, particularly in the production of adhesives and contact materials.
Innovation Solution
A method involving polymerization of chloroprene to a maximum solids content of ≤30% in an emulsion, followed by multi-stage stripping to achieve a chloroprene content ≤10ppm, utilizing a stripper column with controlled steam condensation and additional aqueous phase to prevent coagulum formation, allowing for extended operational times and improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If steam distillation is used to reduce monomeric chloroprene content, then chloroprene content is reduced, but the stripper column is blocked by polychloroprene coagulum
Solution Approach 1:
The patent changes the temperature parameter in the stripper column from conventional high-temperature steam distillation to a lower temperature range (50-100°C), which prevents polychloroprene coagulum formation while still effectively removing monomeric chloroprene through controlled steam stripping
Solution Approach 2:
The patent uses a composite approach by combining diluted polychloroprene dispersion with aqueous phase in the stripper column, creating a system where the aqueous phase prevents coagulum formation while allowing chloroprene removal
2Productivity
If solids content is increased to improve productivity, then polymer concentration is improved, but coagulum formation increases blocking the stripper column
Solution Approach 1:
The patent optimizes the solids content parameter to a specific range (10-50% by weight) that balances productivity with operational reliability, preventing coagulum formation while maintaining effective chloroprene removal
Solution Approach 2:
The patent introduces an aqueous phase as an intermediary substance in the stripper column that mediates between the polychloroprene dispersion and steam, preventing coagulum formation while facilitating chloroprene removal
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 over 3 weeks, significantly reducing chloroprene content in the purified dispersion, enhancing handling and safety of polychloroprene-based products while preventing coagulum blockages and improving industrial hygiene.
Implementation Method 1
separating chloroprene from the polychloroprene dispersion in a multi-stage and/or multi-tray stripper column up to a chloroprene content wCR,out ≤ 50ppm
Implementation Method 2
a polymerization of chloroprene to polychloroprene is carried out in an emulsion
Implementation Method 3
utilizing a stripper column with controlled steam condensation and additional aqueous phase to prevent coagulum formation
Data Source
Figure 1
AI summary
The invention relates to a system (10) and a method for producing a polychloroprene-based polymer dispersion, comprising the steps of carrying out a polymerization of chloroprene to polychloroprene in an emulsion up to a maximum solids content wsolid in weight proportions of wsolid ≤ 50%, particularly wsolid ≤ 40%, preferably wsolid ≤ 35% and particularly preferably wsolid ≤ 30% in a polychloroprene dispersion present after polymerization, and separating chloroprene from the polychloroprene dispersion in a multi-stage and/or multi-tray stripper column (36) to a chloroprene content wCR,out in weight proportions of wCR,out ≤ 50ppm, particularly wCR,out ≤ 30ppm, preferably wCR,out ≤ 15ppm and particularly preferably wCR,out ≤ 10ppm in a purified polychloroprene dispersion present after separating chloroprene. The content of monomer chloroprene in polychloroprene dispersions can be reduced by means of said system (10) and said method without having to accept a significant decrease of the operating times of the system components used.