| abstract |
The object of the invention is a process for producing compact and preferably cellular polyurethane elastomers based on 3,3' dimethyl diphenyl 4,4' diisocyanate-containing polyisocyanate mixtures by the reaction of a) high-molecular polyhydroxyl compounds and possibly b) low-molecular hydroxyl group-containing chain extending and/or cross-linking agents with c) 3,3' dimethyl diphenyl 4,4' diisocyanate and at least one additional aromatic diisocyanate from the group toluylene diisocyanate, diphenyl methane diisocyanate, 1,2 diphenyl ethane diisocyanate and phenylene diisocyanate, and/or at least one aliphatic diisocyanate with 4 to 12 carbon atoms and/or at least one cycloaliphatic diisocyanate with 6 to 18 carbon atoms, in which the structural components (a), (c) and possibly (b) are advantageously brought to reaction by the prepolymer process, in the presence or absence of d) catalysts, e) foaming agents and f) additives and isocyanate prepolymers suitable therefor, preferably those based on 4,4' diphenyl methane diisocyanate and 3,3' dimethyl diphenyl 4,4' diisocyanate. |