Abstract: Pressure-sensitive adhesives which are mixed immediately prior to application, or need drying equipment tend to be expensive in use while those applied as hot melts tend to have poor heat resistance. According to the invention an adhesive composition curable by atmospheric moisture is provided, the composition comprising a prepolymer component with isocyanate functionality between 2.0 and 3.0 together with one or more polyetherurethane prepolymers having NCO groups available for reaction with water for chain extension, the cured adhesive composition having a glass transition temperature below 20.degree. C.

Abstract: Novel, solvent free adhesive compositions comprising a moisture curable polyurethane formed from a first component comprising a diisocyanate, and a second component comprising a substantially linear hydroxy polyester in proportions to provide a prepolymer having from 1.0 to 2.0 percent by weight --NCO groups available for reaction, and a third component comprising a monofunctional reactant present in an amount sufficient to react with 1-40 mole % of the reactive --NCO groups of the product of the prepolymer reaction. A layer of applied adhesive may be exposed to airborne moisture under relatively mild conditions to bring about chain extension of the moisture curable polyurethane, after which the layer of the adhesive composition may be heated to bring it to tacky adhesive condition. The chain extended adhesive composition is storable for at least several days without affecting the bond strength.