Abstract: Cellular polyisocyanate polyadducts are prepared by reacting (a) isocyanates with (b) compounds reactive toward isocyanates and (d) water, by a process in which a polyester having 2 hydroxyl groups and based on the condensation of at least one dicarboxylic acid with at least one alkanediol and/or alkenediol of 3 to 6 carbon atoms, whose carbon skeleton has at least one alkyl and/or alkenyl side chain between the hydroxyl groups, is used as (b).

Abstract: Compact and preferably cellular polyurethane elastomers based on polyisocyanate mixtures containing 3,3′-dimethylbiphenyl 4,4′-diisocyanate are produced by reacting a) relatively high molecular weight polyhydroxyl compounds and, if desired, b) low molecular weight hydroxyl-containing chain extenders and/or crosslinkers with c) 3,3′-dimethylbiphenyl 4,4′-diisocyanate and at least one additional aromatic diisocyanate selected from the group consisting of tolylene diisocyanate, diphenylmethane diisocyanate, 1,2-diphenylethane diisocyanate and phenylene diisocyanate, and/or at least one aliphatic diisocyanate having from 4 to 12 carbon atoms and/or at least one 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 of d) catalysts, e) blowing agents and f) additives.

Abstract: Compact and preferably cellular polyurethane elastomers are produced by reacting a) polyhydroxyl compounds having molecular weights of from 800 to 6000 and, if desired, b) chain extenders and/or crosslinkers having molecular weights of up to 800 [lacuna] c) naphthylene 1,5-diisocyanate 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 phenylene 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 preferably reacted by the prepolymer method, in the presence or absence of d) catalysts, e) blowing agents and f) additives. Isocyanate prepolymers suitable for this purpose are also described.

Abstract: Compact and preferably cellular polyurethane elastomers are prepared by reacting a) relatively high molecular weight polyhydroxyl compounds and if desired, b) low molecular weight chain extenders and/or crosslinkers with c) 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 of d) catalysts, e) blowing agents and f) additives. Isocyanate prepolymers suitable for this purpose are described.

Abstract: Polyurethanes are recycled by comminution to particle sizes of from 0.01 to 2 mm and addition to the polyaddition mixture for preparing polyurethanes from(a) polyisocyanates,(b) substances reactive toward isocyanates and having active hydrogens, and, if desired,(c) chain extenders and/or crosslinkers, catalysts, blowing agents and customary additivesin an amount of from 0.1 to 40% by weight, based on the poly-addition mixture.