Silane-cured Adhesives and Sealants: Trends in Silane Technology

摘要

Silane-cured urethanes for adhesives and sealants occupy a rapidly growing and specialized area of urethane chemistry. Silane endcappers, silane adhesion promoters, and silane water scavengers greatly influence physical properties such as modulus, flexibility, and strength of the final product. The paper outlines the preparation of silane-encapped urethanes by reacting traditional urethane prepolymers with secondary aminosilanes such as DYNASYLAN~(~R) 1189. DYNASYLAN~(~R) 1189 allows a fast reaction with free NCO's and achieves low prepolymer viscosities. In addition, silane-cured urethane sealants were prepared and the impact of various silane adhesion promoters on the final product's shelf life, crosslinking speed, physical properties, and dry and wet adhesion performance were reviewed. Difunctional aminosilanes and secondary aminosilanes greatly increase the elasticity of the final product. Excellent adhesion on polar substrates is found.