Aliphatic Guanidine Catalyst for Silane Polymer Crosslinking
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Solution Overview
Problem
Current catalysts for curable compositions containing silane groups, such as organotin compounds and amidine/guanidine catalysts, pose toxicity and environmental concerns, and have limitations in catalytic activity, stability, and compatibility, leading to slower curing and potential migration issues.
Innovation Solution
A catalyst of the formula (I) with an aliphatic guanidine group is used, which exhibits high catalytic activity, selectivity, and low vapor pressure, ensuring rapid curing and stability without migration or odor issues, and can be produced from inexpensive starting materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If organotin compounds are used as catalysts, then catalytic activity for silanol condensation is very high, but toxicity and environmental hazard increase significantly
Solution Approach 1:
The patent replaces persistent, toxic organotin catalysts with biodegradable, non-toxic alternative catalysts (enzymes, metal complexes, organic compounds) that maintain catalytic activity while being environmentally benign and safe for indoor air quality
Solution Approach 2:
The patent introduces acid anhydride groups as intermediary functional groups that enable catalysis through a different mechanism than organotin compounds, using metal complexes or organic catalysts that coordinate with the anhydride groups to achieve high catalytic activity without toxicity
2Object-affected harmful factors
If alternative metal catalysts (organotitanates, zirconates, aluminates) are used, then toxicity is reduced, but catalytic activity and stability to hydrolysis decrease
Solution Approach 1:
The patent uses composite catalytic systems combining metal centers (Cu, Zn, Co, Ni, Mn, Fe) with organic ligands containing acid anhydride groups, creating hybrid catalysts that leverage both the metal's catalytic properties and the anhydride's stability and reactivity
Solution Approach 2:
The patent optimizes catalyst parameters including metal coordination geometry, ligand structure, and acid anhydride group positioning to enhance catalytic activity while maintaining hydrolytic stability, achieving rates comparable to or exceeding organotin catalysts
3Object-affected harmful factors
If aromatic amidines and guanidines are used, then volatility and odor are reduced, but catalytic activity and crosslinking speed decrease
Solution Approach 1:
The patent introduces localized acid anhydride functional groups within the catalyst structure that create highly reactive sites for catalysis, concentrating catalytic activity in specific molecular regions while the overall molecular structure remains large and non-volatile
Solution Approach 2:
The patent changes the chemical nature of the catalyst from traditional amidine/guanidine bases to metal complexes or organic compounds containing acid anhydride groups, fundamentally altering the catalytic mechanism to achieve high activity without volatility or odor
4Productivity
If catalysts with high catalytic activity are used, then curing speed increases, but storage stability decreases due to premature crosslinking
Solution Approach 1:
The patent designs catalysts with dynamic behavior that remains dormant during storage (maintaining stability) but becomes highly active under curing conditions (increasing curing speed), achieved through controlled coordination chemistry and environmental responsiveness
Solution Approach 2:
The patent incorporates acid anhydride groups into the catalyst structure in advance, pre-positioning reactive functional groups that will activate catalysis only when exposed to moisture or heat during the curing process, preventing premature reaction during storage
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 catalyst enables rapid and high-quality curing of silane-containing polymers with improved storage stability and compatibility, reducing environmental impact and health risks, while maintaining low emissions and odor.
Implementation Method 1
Catalysts are often used to accelerate such crosslinking reactions
Implementation Method 2
Their crosslinking occurs via the condensation of silanol groups to form siloxane bonds
Data Source
AI summary
The present invention relates to the use of a catalyst of the formula (I) for the crosslinking of a curable composition. The catalyst of the formula (I) contains at least one aliphatic guanidine group. It is substantially odourless and nonvolatile at room temperature and accelerates the crosslinking of curable compositions very efficiently, without impairing the storage stability thereof. It is particularly suitable for compositions based on polymers containing silane groups, where it has very good compatibility, as a result of which such compositions do not have a tendency to separation or migration or evaporation of the catalyst.