Applicable Base Polymer Properties
Polyurethanes are extensively and successfully used as adhesives and sealants, and they have an excellent record of durability. Blocked isocyanates are used in some of these formulation. It is typically formed by the reaction of an active hydrogen or methylene compound such as ε-caprolactam, butanone oxime, phenol, or malonic ester. At room temperature these blocked isocyanates do not react with the polyol, thus providing long shelf life. This can be used to advantage in the manufacture of shelf stable, rapid curing, two component polyurethane adhesives and sealants. For example, the use of a bi-primary amine results in a rapid curing sealant for glazing.