Ethyl Corporation

James H Simon

Christopher J Nalepa

J Kenneth Presswood

Novel polyurethanes having superior high temperature performance are prepared by reacting 3,5-di(methylthio)2,6-diaminotoluene with a toluenediisocyanate prepolymer having a free --NCO content of 0.1-20% by weight, preferably a toluenediisocyanate/polyether glycol prepolymer having a free --NCO content of 2-7% by weight. The elastomers have good dynamic properties, such as resilience, that make them attractive as tire-forming materials.

Polyurethanes

Blends of 90-99 mol % of a polyhydroxyalkane containing 2-6 carbons and 2-3 hydroxyl groups and 1-10 mol % of an aromatic diamine having a pKb value greater than 11.3 are useful as chain extenders for polyurethanes derived from diphenylmethanediisocyanate (MDI) prepolymers. Their use overcomes the sensitivity to stoichiometry common to MDI prepolymer/polyhydroxyalkane systems and leads to the formation of cast elastomers having better green strength and a shorter demold time. The preferred blends are blends of 1,4-butanediol and di(alkylthio)toluenediamines.

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Coralville, IA, United States of America

James H Simon