Amidine Catalyst for Silane Crosslinking

The patent changes the chemical parameters of the catalyst by replacing organotin compounds with organotitanate, zirconate, or aluminate compounds. These alternative catalysts have different chemical properties that reduce toxicity while maintaining crosslinking activity. The patent specifically uses metal alkoxides or metal carboxylates with controlled molecular weights and functional groups to achieve both low toxicity and high catalytic performance in silane crosslinking reactions.

The patent employs catalysts that are less persistent and less toxic than organotin compounds. The organotitanate, zirconate, and aluminate catalysts described are designed to be more environmentally benign and less hazardous, effectively replacing the harmful organotin compounds with safer alternatives that still provide the necessary crosslinking function.

The patent optimizes the molecular weight, functional groups, and structural parameters of the alternative metal catalysts to enhance their crosslinking activity. By carefully selecting metal alkoxides or carboxylates with specific properties, the patent achieves high crosslinking speeds comparable to organotin compounds while maintaining the lower toxicity of the alternative metals. The patent controls parameters such as metal-to-alkoxide ratio, molecular weight of the organic ligand, and presence of co-catalysts to maximize reaction rate.

The patent may use composite catalyst systems combining alternative metal compounds with organic co-catalysts or promoters to achieve synergistic effects. This composite approach allows the alternative metal catalyst to provide low toxicity while the organic components enhance the crosslinking speed, effectively resolving the contradiction between safety and performance.

The patent carefully controls the hydrolysis resistance parameters of the alternative metal catalysts by selecting metals and ligands with appropriate properties. The patent uses metal alkoxides or carboxylates with controlled water sensitivity, balancing storage stability against catalytic activity. By adjusting the molecular weight of the organic ligand, the metal-to-alkoxide ratio, and the presence of protective groups, the patent achieves catalysts that remain stable during storage but become highly active under crosslinking conditions.

The patent may incorporate preliminary protective measures such as using water-scavenging agents, controlling moisture content in the composition, or pre-forming stable catalyst complexes that only become active when needed. This allows the catalyst to maintain storage stability while ensuring high catalytic activity is available when the crosslinking reaction commences.