Patent ID: 9745437
Date: 2017-08-29
CPC Classifications: B60G,C08G,C08J,F16F

Claim:
1. A method of preparing a microcellular polyurethane elastomer, comprising: (i) reacting naphthalene diisocyanate (NDI) with a polyol to obtain a prepolymer containing an isocyanate (NCO) group; (ii) adding a plasticizer and an additional amount of naphthalene diisocyanate to the prepolymer prepared in step (i) to introduce into the prepolymer a terminal free isocyanate (NCO) group having 5 to 30 wt % of an allophanate structure, based on the weight of the prepolymer; and (iii) mixing the prepolymer having a terminal free isocyanate (NCO) group obtained in step (ii) with water and an emulsifier to obtain a prepolymer blend and then foaming the prepolymer blend to prepare a polyurethane elastomer, and wherein the emulsifier is prepared from a mixture of (a) a compound selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,4′-cyclohexane diisocyanate and mixtures thereof, and (b) a one or more C