Adhesion promoters: analyzing the preparation of silane-encapped polyurethane (PU) by reacting isocyanate PU prepolymers with secondary aminosilanes

摘要

Polyurethane (PU) sealants are used for sealing windows in buildings and cars because of resistance to harsh weather conditions. In the construction industry they are used in concrete expansion joints and as pre-formed gasket seals in piping. Excellent adhesive properties can be achieved with the addition of silanes. Silanes are excellent adhesion promotors because of their ability to chemically bond organic polymers to inorganic substrates. Silane-endcapped PU polymers occupy a rapidly growing and specialized area of sealant production. This article outlines the preparation of silane-endcapped PUs by reacting isocyanate PU prepolymers with secondary aminosilanes such as Dynasylan 1189 (1). Dynasylan 1189 allows fast reaction with free isocyanates at a high conversion and achieves low prepolymer viscosities.