Silane-Terminated Polymer Catalysis for Fast Stable Conversion
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Solution Overview
Problem
Existing methods for preparing silane-terminated polymers require long reaction times and large amounts of catalysts, leading to unwanted side reactions and reduced storage stability of the end products.
Innovation Solution
A catalyst mixture comprising bismuth and cobalt catalysts is used to accelerate the reaction between hydroxy-terminated organic polymers and isocyanates, achieving rapid but complete conversion of OH groups, with the cobalt catalyst content being at least 2 ppm and bismuth catalyst content being at least 10 ppm based on the hydroxy-terminated polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If large amounts of bismuth catalyst are used to accelerate the reaction, then reaction rate is improved, but reaction time is extended and storage stability deteriorates
Solution Approach 1:
The patent combines bismuth catalyst and cobalt catalyst in a mixed catalyst system. The bismuth catalyst (e.g., bismuth triacetate) provides baseline catalytic activity for the isocyanate-silane reaction, while the cobalt catalyst (e.g., cobalt acetylacetonate) significantly accelerates the reaction rate. This synergistic combination achieves complete conversion in 60-120 minutes, overcoming the limitation of using bismuth catalyst alone which requires extended reaction times.
Solution Approach 2:
The patent optimizes the concentration parameters of both catalysts to achieve the desired reaction rate. Specifically, the bismuth catalyst is used at 10-1000 ppm and the cobalt catalyst at 2-200 ppm based on the hydroxy-terminated polymer. This parameter optimization ensures rapid complete conversion while minimizing side reactions and maintaining storage stability of the final product.
2Manufacturing precision
If large amounts of catalyst are used to achieve complete conversion, then conversion completeness is improved, but storage stability deteriorates
Solution Approach 1:
The patent carefully controls the catalyst concentration parameters to achieve complete conversion without excess catalyst remaining in the final product. The bismuth catalyst is used at 10-1000 ppm and cobalt catalyst at 2-200 ppm, with optimal ranges identified. This precise parameter control ensures that the reaction goes to completion (≥99% conversion of isocyanate groups) while the catalyst amounts are sufficient to be consumed or deactivated, thereby maintaining the storage stability of the silane-terminated polymer.
3Manufacturing precision
If long reaction times are used to achieve complete conversion, then conversion completeness is improved, but energy consumption increases
Solution Approach 1:
The mixed catalyst system of bismuth and cobalt catalysts works synergistically to provide high catalytic activity at lower concentrations and shorter reaction times. The cobalt catalyst component specifically accelerates the reaction rate, enabling complete conversion within 60-120 minutes. This significantly reduces the energy input required compared to using bismuth catalyst alone which would require extended reaction times and consequently higher energy consumption.
4Reliability
If bismuth catalyst alone is used, then storage stability is maintained, but reaction rate is insufficient
Solution Approach 1:
The patent combines bismuth catalyst (which maintains storage stability) with cobalt catalyst (which provides high reaction rate) in a mixed catalyst system. The bismuth catalyst component ensures that the final product maintains good storage stability, while the cobalt catalyst component accelerates the reaction to completion within 60-120 minutes. This synergistic combination overcomes the limitation of using bismuth catalyst alone, which provides storage stability but insufficient reaction rate.
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 significantly shortens reaction time by 50-65%, maintains storage stability, and reduces energy consumption, allowing for efficient production of silane-terminated polymers suitable for sealants and coatings.
Implementation Method 1
The reaction is effected in the presence of a catalyst mixture which contains a bismuth catalyst and a cobalt catalyst... the catalyst mixture leads to significant shortening of the reaction time... The catalyst mixture of the invention is much more effective than pure bismuth catalysts or catalyst mixtures comprising bismuth catalysts and zinc catalysts.
Data Source
AI summary
A process for producing a silane-terminated polymer in the presence of a catalyst mixture, wherein the catalyst mixture contains a bismuth and a cobalt catalyst, and the content of the cobalt catalyst is at least 2 ppm relative to the hydroxy-terminated organic polymer of the formula.