cted from the groupconsisting of polycaprolactone glycol, poly(1,6-hexanediol carbonate), trimethylol propane and polyoxypropylene diamine and a diisocyanate having the formula: ##STR4## in which X is an alkyl group containing from 1-4 carbon atoms or hydrogen and acationic photoinitiator, and exposing said film to ultraviolet light to cure the same.2.