Ethylene-Silane Copolymer Reactor Zone Silane Injection
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Solution Overview
Problem
Current methods for producing ethylene-silane copolymers with hydrolysable silane groups require high amounts of vinylsilane monomer, leading to inefficient conversion and increased energy consumption, as well as issues with wax formation and monomer losses during recirculation in high-pressure radical polymerization processes.
Innovation Solution
Introducing more than 60% by weight of the silane compound, preferably all, into the first reaction zone of a multi-zone reactor during radical-initiated polymerization of ethylene and an unsaturated silane compound at high pressure and temperature, enhancing the conversion of silane monomer into polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high amounts of vinylsilane monomer are used in conventional polymerization, then the copolymer can be produced, but the conversion efficiency decreases and energy consumption increases
Solution Approach 1:
The patent divides the polymerization process into multiple reaction zones with different temperature profiles. The first zone operates at higher temperature (90-150°C) to promote rapid silane monomer conversion, while subsequent zones operate at lower temperatures (70-90°C) to control the overall reaction. This segmentation allows optimal conversion efficiency in the first zone without excessive energy input throughout the entire reactor.
Solution Approach 2:
The patent optimizes specific parameters including silane monomer content (0.5-5 wt%), temperature distribution across zones, and pressure conditions (1-10 bar). By carefully controlling these parameters, particularly the temperature gradient and silane concentration in the first reaction zone, the process achieves high conversion efficiency while minimizing energy consumption.
2Productivity
If conventional polymerization methods are used, then copolymer production is achieved, but wax formation and monomer losses occur during recirculation
Solution Approach 1:
The patent performs the majority of silane monomer conversion in the first reaction zone before the monomer enters recirculation loops. By achieving 60-90% conversion in the first zone, the amount of monomer available to form waxes during recirculation is significantly reduced, minimizing this harmful effect.
Solution Approach 2:
The patent converts the potential harm of monomer recirculation into a benefit by using the recirculation stream to provide additional heat transfer capacity and maintain monomer mixing, while the high initial conversion prevents wax formation. The recirculation system becomes useful for process control rather than a source of problems.
3Productivity
If multi-zone reactor with optimized first zone is used, then silane monomer conversion is enhanced, but reactor complexity increases
Solution Approach 1:
The reactor is divided into multiple zones with the first zone designed for high silane conversion and subsequent zones for completion of polymerization. This segmentation achieves high productivity through optimized temperature and concentration profiles in each zone while using standard reactor design elements that are commercially available.
Solution Approach 2:
The multi-zone reactor configuration serves multiple functions: the first zone provides high conversion of silane monomer, subsequent zones complete the polymerization, and the zoned temperature profile also provides heat management benefits. This multi-functionality justifies the increased complexity by delivering multiple process benefits simultaneously.
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 significantly increases the yield of ethylene-silane copolymer, reducing the amount of vinylsilane monomer needed and minimizing energy consumption and monomer losses, while also simplifying the processing steps and reducing contamination risks.
Implementation Method 1
the silane groups are hydrolysed under the influence of water or steam, resulting in the splitting-off of alcohol and the formation of silanol groups
Implementation Method 2
the silanol groups are crosslinked by a condensation reaction splitting off water
Implementation Method 3
the peroxide is decomposed to form free radicals
Data Source
AI summary
The present invention relates to an improved method for preparing an ethylene-silane copolymer comprising hydrolysable silane groups by radical-initiated polymerisation of ethylene and an olefinically unsaturated silane compound, such as vinyl trimethoxysilane (VTMS). Said method is performed in a multi-zone reactor comprising two or more reaction zones, wherein advantageously essentially all of the silane compound is introduced into the first reaction zone to provide a higher conversion of silane monomer into polymer.