Amidine Catalyst Crosslinking Silane Polymers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional catalysts for crosslinking compositions containing silane groups, such as organotin compounds and amidine-based catalysts, pose health and environmental hazards due to toxicity, volatility, and migration issues, leading to slower curing and storage stability concerns.
Innovation Solution
An amidine of a specific formula with an aliphatic amidine group, which is nonvolatile and odorless at room temperature, is used as a catalyst for crosslinking compositions, offering high catalytic activity and selectivity, ensuring rapid curing and improved storage stability without migration or separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If organotin compounds are used as catalysts, then high catalytic activity and hydrolysis resistance are achieved, but health and environmental hazards increase due to toxicity
Solution Approach 1:
The patent changes the chemical parameters of the catalyst by replacing organotin compounds with organometallic compounds containing early transition metals (Groups 3-10). This substitution maintains catalytic activity while reducing toxicity, as the new catalyst system achieves comparable curing rates without the severe health and environmental hazards associated with organotin compounds.
Solution Approach 2:
The patent employs catalysts that are less persistent and less toxic than organotin compounds. The organometallic catalysts based on early transition metals are designed to be effective during the curing process but do not pose long-term environmental hazards, effectively replacing persistent toxic substances with shorter-lived, safer alternatives.
2Object-affected harmful factors
If organometallic compounds of early transition metals are used as alternative catalysts, then toxicity is reduced, but catalytic activity and hydrolysis stability decrease leading to slower curing
Solution Approach 1:
The patent uses composite catalyst systems comprising organometallic compounds of early transition metals combined with specific ligands (amides, amino acid derivatives, carboxylic acid derivatives). This composite approach enhances the catalytic activity and hydrolysis stability of the individual components, achieving both reduced toxicity and maintained high curing rates through synergistic effects.
Solution Approach 2:
The patent optimizes the molecular structure and composition parameters of the organometallic catalysts by selecting specific ligands and metal combinations. These parameter adjustments increase the hydrolysis stability and catalytic activity of the catalysts, enabling them to maintain high curing rates despite the inherent lower activity of early transition metal compounds compared to organotin catalysts.
3Object-affected harmful factors
If aromatic amidines and guanidines are used to reduce volatility and odor, then health and environmental hazards are reduced, but catalytic activity and crosslinking rate decrease
Solution Approach 1:
The patent combines aromatic amidines or guanidines with organometallic compounds of early transition metals in a composite catalyst system. This combination compensates for the lower catalytic activity of the aromatic amidines/guanidines by leveraging the high activity of the organometallic catalysts, thereby maintaining fast crosslinking rates while benefiting from the reduced volatility and odor of the aromatic compounds.
Solution Approach 2:
The patent merges the advantages of different catalyst types by combining the low volatility and odor characteristics of aromatic amidines/guanidines with the high catalytic activity of organometallic compounds. This merging creates a synergistic catalyst system that achieves both reduced harmful emissions and maintained high crosslinking performance.
4Productivity
If catalysts with high basicity are used to accelerate hydrolysis, then curing speed increases, but storage stability is impaired due to premature crosslinking
Solution Approach 1:
The patent carefully adjusts the basicity parameter of the catalyst system by selecting appropriate ligands and metal combinations. The organometallic catalysts are designed with moderate basicity that is sufficient to accelerate the desired crosslinking reaction but not so high as to cause premature hydrolysis and crosslinking during storage. This parameter optimization enables both fast curing when applied and stable storage before application.
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 amidine catalyst enables rapid and high-quality curing of silane-containing compositions with improved storage stability and low emission, reducing health and environmental risks while preventing substrate soiling and migration-related defects.
Implementation Method 1
Catalysts are frequently used to accelerate the curing. These are very often substances of toxicological concern... Crosslinking catalysts used conventionally are organotin compounds... highly basic nitrogen compounds from the class of the amidines and guanidines
Implementation Method 2
They are cured via crosslinking reactions of the silane groups, which are hydrolyzed under the influence of moisture
Implementation Method 3
condense with one another as silanol groups and in so doing form siloxane bonds
Data Source
AI summary
The use of an amidine of formula (I) and/or a conversion product thereof as a catalyst for the crosslinking of a composition based on silane group-containing polymers. The amidine of formula (I) and the conversion products thereof are essentially odorless at room temperature and non-volatile and accelerate the crosslinking of the composition very well without impairing the storage stability of the composition, and are very compatible in the composition. As a result, the compositions do not have a tendency to separate, migrate or evaporate the catalyst.