The Gates Corporation

James R Stamp

Joseph R Duke, Jr

William W L Wu

Harry D Visser

William Wu

W Joe Brothers

A power transmission belt having a main belt body portion of elastomeric material, a tensile reinforcement such as carbon fiber cord, disposed in said body portion, and a sheave contact portion integral with said main body portion. The elastomeric material includes the reaction product of a polyisocyanate prepolymer composition and a chain extender. The polyisocyanate prepolymer composition is prepared by reacting a diisocyanate and a polyol substantially free of moieties oxidative at less than about 150&#xb0; C. and at least one triol crosslinker selected from the same group of polyols. Either before or after reacting the prepolymer, a plasticizer selected from the group consisting of alkyl-ether di-alkylesters such as polyethylene glycol di-alkylester is added thereto. The chain extender is an aromatic symmetric primary or secondary diamine chain extenders.

Polyurethane power transmission belt

The present invention relates to molded polyurethane/urea elastomers, and specifically to improved polyurethane/urea elastomers having high temperature stability to about 140&#x2013;150&#xb0; C. and low temperature flexibility at about &#x2212;35&#x2013;(&#x2212;40)&#xb0; C., for use in dynamic applications. These elastomers are particularly useful for application in belts, specifically in automotive timing or synchronous belts, V-belts, multi V-ribbed or micro-ribbed belts, flat belting and the like. The polyurethane/urea elastomers of the present invention are prepared by reacting polyisocyanate prepolymers with symmetric primary diamine chain extenders, mixtures of symmetric primary diamine chain extenders and secondary diamine chain extenders, or mixtures of symmetric primary diamine chain extenders and non-oxidative polyols, which are all chosen to eliminate the need for catalysts via standard molding processes, and to improve phase separation. The polyisocyanate prepolymers are reaction products of polyols which are nonoxidative at high temperatures, such as polycarbonate polyols, polyester polyols, or mixtures thereof, with organic polyisocyanates which are either compact, symmetric and aromatic, such as para-phenylene diisocyanate, 1,5-naphthalene diisocyanate, and 2,6-toluene diisocyanate, or are aliphatic and possess trans or trans,trans geometric structure, such as trans-1,4-cyclohexane diisocyanate and trans,trans-4,4'-dicyclohexylmethyl diisocyanate.

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Elizabethtown, KY, United States of America

James R Stamp