Chemistry of phenolic and epoxy adhesive

The acidity of a resole is of importance for the final curing and the adhesion properties. In the curing a partial conversion of methylhydroxy groups to methylene bridges takes place. Good properties of the adhesive are only achieved if the crosslinking is not too high, which is ruled by the acidity. The curing of epoxides with amines runs stepwise. It begins with the formation of a linear polymer which is later crosslinked to a threedimensional network.