Thermally Latent Tin Catalysts for Polyurethane Curing
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Solution Overview
Problem
Current methods for producing polyurethanes with silane groups rely on toxicological questionable catalysts like DBTL, which are not environmentally friendly and require additional toxic tin-containing catalysts, affecting the viscosity, stability, and color of the products, and lack efficient curing without organotin catalysts.
Innovation Solution
A process involving the reaction of compounds with NCO groups and Zerewitinoff-active H atoms using thermally latent cyclic tin compounds as catalysts, which are activated above 50°C to produce polyurethanes with alkoxysilane groups, reducing the need for toxic catalysts and maintaining product stability and viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DBTL catalyst is used to produce polyurethanes with silane groups, then the production process is efficient, but the product has toxicological disadvantages and requires additional toxic tin-containing catalysts
Solution Approach 1:
The patent extracts and removes the harmful DBTL catalyst from the polyurethane production process, replacing it with a non-toxic alternative. This eliminates the need for additional toxic tin-containing catalysts while maintaining production efficiency, directly resolving the contradiction between productivity and toxicological safety.
Solution Approach 2:
The patent employs a non-toxic catalyst that does not require removal or special handling, effectively replacing the problematic DBTL catalyst. This substitution eliminates long-term toxicological concerns and the need for additional catalyst management, resolving the contradiction between efficient production and harmful factors.
2Speed
If tin-containing catalysts are added to achieve practical curing times, then the curing rate is improved, but the viscosity, stability, and color of the products are negatively affected
Solution Approach 1:
The patent introduces a non-toxic catalyst as an intermediary substance that enables the curing reaction without the harmful side effects of tin-containing catalysts. This mediator achieves practical curing times while preserving product stability, color, and viscosity, resolving the contradiction between curing speed and composition stability.
3Loss of time
If gamma-silane groups are used to increase reactivity, then the curing time is reduced, but the amount of tin-containing catalyst required increases
Solution Approach 1:
The patent removes the dependency on tin-containing catalysts by using a non-toxic alternative that works effectively with gamma-silane groups. This extraction of the harmful catalyst requirement allows the system to maintain reduced curing times without increasing catalyst quantity or toxicity, resolving the contradiction between curing time and catalyst amount.
4Speed
If alpha-silane groups are used to achieve rapid curing, then the curing speed is improved, but the polymers become unstable, expensive, and difficult to obtain
Solution Approach 1:
The patent uses a non-toxic catalyst as an intermediary that enables rapid curing with gamma-silane groups without requiring the unstable and difficult-to-obtain alpha-silane polymers. This mediator achieves fast curing speeds while maintaining polymer stability and ease of manufacture, resolving the contradiction between curing speed and ease of manufacture.
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 method allows for the production of polyurethanes that can be cured quickly without organotin catalysts, maintaining product stability and viscosity, and avoiding the toxicological disadvantages of traditional catalysts, while ensuring effective curing and improved safety.
Implementation Method 1
reacting a compound containing at least one NCO group with a compound containing at least one Zerewitinoff-active hydrogen atom in the presence of a catalyst component
Implementation Method 2
Moisture-curing compositions based on silane-functional polymers
Implementation Method 3
silane groups, which affects the curing rate of the moisture-curing compositions
Data Source
AI summary
The invention relates to a method for preparing polyurethanes containing alkoxysilane groups, said method comprising the step of reacting a compound containing at least one NCO group with a compound containing at least one Zerewitinoff-active H atom in the presence of a catalyst component, the at least one compound containing an NCO group and/or the compound containing at least one Zerewitinoff-active H atom containing at least one alkoxysilane group, so as to obtain a polyurethane containing alkoxysilane groups. The invention also relates to a polymer containing alkoxysilane groups, a method for preparing a curable polymer, a curable polymer, a cured polymer, and use thereof. The polyurethanes are prepared with use of a thermally labile tin catalyst.