Urea-urethane compositions and films prepared therefrom

Abstract

Abstract Urethane prepolymer compositions are made from 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane and polyols at a total NCO to OH ratio of at least 1.2:1, and the prepolymers are reacted with cycloaliphatic polyamines to give urea-urethanes. The urea-urethanes can be formed as films such as coatings on a substrate or as indpendent sheets or the urea-urethanes can be formed materials of greater thickness. The products exhibit good strength, high resistance to the discoloring effects of ultraviolet light, elastomeric and other desirable properties. Often the urea-urethane is prepared in solution but this may not be the procedure where the urethane prepolymer and polyamine are combined and more or less immediately placed in the desired form as a film or other article such as is done using a two component spray gun. The polyol component of the composition has as its major component aliphatic polyol having a molecular weight of at least about 500. The glycols, especialy the polyether glycols, are suitable polyol reactants. A variety of polyamines can be employed and cycloaliphatic diamines are preferred reactants. The prepolymers can contain about 1 to 15 weight percent of free isocyanate groups and the prepolymers are often of application viscosity, at least when in a solvent, even when derived from a polyol component containing a significant proportion of polyol having three or more hydroxyl groups and therefore exhibit cross-liking tendencies. Cured coatings made from the urea-urethanes exhibit outstanding resistance to the discoloring action of ultraviolet light rays and possess other desirable properties such as good adherence to substrates and excellent abrasion resistance and strength.

Inventors

• 👤 Herbert M. Schroeder
• 👤 Paul C. Stievater

Bibliographic Details