Method for the Preparation of Microcellular Polyurethane Elastomers

摘要

This invention relates to a method of preparing a microcellular polyurethane elastomer by reacting naphthalene diisocyanate with a polyol to prepare a prepolymer containing an isocyanate (NCO) group, followed by mixing the prepared polyurethane prepolymer with a plasticizer, water, an emulsifier and the like, and then foaming the prepolymer blend to prepare a polyurethane elastomer, wherein the emulsifier is 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 C2-10 hydrocarbon having a molecular weight of 500 or less with two to four hydroxyl groups, or mixtures thereof. The method of the invention can optimize the viscosity and properties of the prepolymer resulting from the reaction of naphthalene diisocyanate with a polyol, thus improving processability.

主权项

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 and then foaming the prepolymer blend to prepare a polyurethane elastomer.