Processo para preparar elastomeros de poliuretano pré-polimero contendo grupos isocianato

Compact and preferably cellular polyurethane elastomers are prepared by reactinga) relatively high molecular weight polyhydroxyl compounds and if desired,b) low molecular weight chain extenders and/or crosslinkers withc) phenylene 1,4-diisocyanate (p-PDI) and at least one additional aromatic diisocyanate selected from the group consisting of tolylene diisocyanate, diphenylmethane diisocyanate, 3,3'-dimethylbiphenyl diisocyanate, 1,2-diphenylethane diisocyanate and/or aliphatic diisocyanate, having from 4 to 12 carbon atoms and/or cycloaliphatic diisocyanate having from 6 to 18 carbon atoms, where the formative components (a), (c) and, if used, (b) are advantageously reacted by the prepolymer method,in the presence or absence ofd) catalysts,e) blowing agents andf) additives.Isocyanate prepolymers suitable for this purpose are described.