Activating plasticizer for urethane prepolymers and complex of alkali metal salt with 4,4'-methylenedianiline.

摘要

Storable polypropylene ether polyurethane compositions composed of (a) a prepolymer of a polypropylene ether glycol and sufficient organic polyisocyanate to give preferably an excess of about 3 to 15 percent NCO in said prepolymer with the proviso that the free NCO is obtained from methylenedi-p-phenyl diisocyanate and (b) a complex of an alkali metal salt with 4,4'-methylenedianiline (MDA), said composition being relatively inactive at temperatures below 100°C, but being heat activatible at much higher temperatures to effect a cure. The improved composition wherein a catalyst is present in said composition which effectively lowers the cure temperature, said catalyst being a pseudocrown ether containing radicals having the formula +y-CH₂-CH₂-)- with y being nitrogen, sulfur or oxygen and n has values sufficient to form the crown structure, viz at least 3 or more.