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: Carbodiimides based on 1,3-bis(1-methyl-1-isocyanatoethyl)benzene contain from 12 to 40% by weight of ethylene oxide units [—CH2—CH2—O—], based on the weight of the carbodiimides.

Abstract: A microcellular PU elastomer having improved dynamic-mechanical properties and based on an isocyanate component consisting essentially of 4,4'-MDI and also further customary constituents has, after heating at from 100 to 120.degree. C. for from 8 to 24 hours, a melting range of from 130.degree. C. as the minimum lower limit to 230.degree. C. as a minimum upper limit, measured by differential scanning calorimetry (DSC) at a heating rate of 20.degree. C./min, and a urea content of from 14 to 18% by weight.A process is also provided for preparing such a microcellular PU elastomer having improved dynamic mechanical properties. The microcellular PU elastomers can be used for producing damping elements.

Abstract: A microcellular PU elastomer having improved dynamic mechanical properties and based on an isocyanate component consisting essentially of 4,4'-MDI and further customary constituents has a physicochemical structure which, in the gel permeation chromatograph (GPC) of a solution of the microcellular polyurethane elastomer prepared at 90.degree. C. in N,N-dimethylformamide containing 1 percent of di-n-butylamine measured against polymethyl methacrylate (PMMA) as standard, displays a signal occurring in addition to low molecular weight main signal and comprising one or more peaks at an (apparent) molar mass of greater than 250,000 g/mol which becomes smaller or disappears on addition of lithium chloride to this solution, and a urea content of from 14 to 18% by weight.A process is also provided for preparing such a microcellular PU elastomer having improved dynamic mechanical properties. The microcellular PU elastomers can be used for producing damping elements.

Abstract: A process for the preparation of moldings, in particular resilient elements, which by virtue of a densified surface zone with substantially closed cells, have only a low water absorption, wherein a mixture comprising:(a) 100 parts by weight of an NCO-containing prepolymer, having an NCO content of from 3 to 6% by weight and based on organic diisocyanates and substantially linear polyester-polyols or polytetramethylene ether glycol,(b) from 0.5 to 1.6 parts by weight of water,(c) one or more catalysts, preferably a tertiary amine, in an amount of from 0.01 to 2.0 parts by weight and(d) assistants, with or without additives, is reacted in a closed mold, while undergoing densification, the surface temperature of the inner wall of the mold being from 50.degree. to 70.degree. C.

Abstract: A process for the manufacture of non-cellular and cellular polyurethane elastomers by(a) preparing a hydroxyl group-containing prepolymer by reacting a higher molecular weight polyhydroxyl compound and optionally a chain extender with an organic diisocyanate at a weight ratio of OH groups to NCO groups of 1.2:1 to 2:1,(b) dividing the prepolymer into two components A and B in a weight ratio of about 80:20 to 20:80,(c) reacting component A with 1,5-naphthylene diisocyanate (NDI) in a weight ratio of OH:NCO groups of about 1:2.5 to 1:12 to produce a terminal NCO group-containing NDI-polyurethane adduct,(d) mixing component B with chain extenders and/or cross-linking agents and/or water, and optionally auxiliaries and additives, and(e) reacting the NDI-polyurethane adduct (from step c) with the mixture from step d.