PROCESS FOR PRODUCING CELLULAR POLYURETHANE ELASTOMERS AND PREPOLYMER CONTAINING ISOCYANATE GROUPS

摘要

1. A process for producing polyurethane elastomers by reacting polyhydroxyl compounds having molecular weights of from 800 to 6000 (a) or their mixtures with chain extenders and/or crosslinkers having molecular weights of up to 800 (b) with organic polyisocyanates (c) in the presence of catalysts, e) blowing agents and (f) additives, wherein the organic polyisocyanates used are naphthylene 1,5-diisocyanate and at least one additional aromatic diisocyanate selected from the group consisting of tolylene diisocyanate, diphenylmethane iisocyanate, 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, and the organic polyisocyanates (c) are used in the form of a prepolymer containing isocyanate groups and prepared from naphthylene 1,5-diisocyanate and additionally at least one other aromatic, aliphatic and/or cycloaliphatic diisocyanate, at least one polyhydroxyl compound (a) and, if desired, chain extenders and/or crosslinkers (b). 2. A process as claimed in claim 1, wherein the polyhydroxyl compounds have a functionality of from 2 to 3. 3. A process as claimed in claim 1, wherein the polyhydroxyl compounds are difunctional, have a molecular weight of from 800 to 3500 and are selected from the group consisting of polyester polyols, hydroxyl-containing polycarbonates and polyoxybutylene glycols. 4. A process as claimed in claim 1, wherein the chain extenders are selected from the group consisting of alkanediols, dialkylene glycols and polyoxyalkylene glycols. 5. A process as claimed in claim 1, wherein the crosslinkers are selected from the group consisting of trihydric or tetrahydric alcohols and oligomeric polyoxyalkylene polyols having a functionality of from 3 to 4. 6. A process as claimed in claim 1, wherein the organic polyisocyanates (c) used comprise a flowable mixture of 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 hexamethylene 1,6-diisocyanate and/or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane. 7. A process as claimed in any of claims 1 to 4, wherein the organic polyisocyanates (c) used comprise a melt of naphthylene 1,5-diisocyanate and diphenylmethane 4,4'-diisocyanate. 8. A process as claimed in any of claims 1 to 4, wherein the organic polyisocyanates (c) are used in the form of a prepolymer containing isocyanate groups and prepared by reacting a partial amount or the total amount of the relatively high molecular weight polyhydroxyl compound (a) or a partial amount or the total amount of the mixture of (a) and a low molecular weight chain extender and/or crosslinker (b) with at least one 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 hexamethylene 1,6-diisocyanate and/or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane to give a polyaddition product containing urethane groups and reacting this polyaddition product with naphthylene l,5-diisocyanate to give the prepolymer containing isocyanate groups. 9. A process as claimed in claim 1, wherein the organic polyisocyanates (c) are used in the form of a prepolymer containing isocyanate groups and prepared by reacting a partial amount or the total amount of the relatively high molecular weight polyhydroxyl compounds (a) 1 to 6 to give a polyaddition product containing urethane and isocyanate groups and reacting this polyaddition product with naphthylene 1,5-diisocyanate in an equivalence ratio of hydroxyl groups of (a) or (a) and (b) to isocyanate groups of naphthylene 1,5-diisocyanate of 1:0.02-6 to form the prepolymer containing isocyanate groups. 11. A process as claimed in claim 1, wherein the organic polyisocyanates (c) are used in the form of a prepolymer containing isocyanate groups and prepared by reacting the relatively high molecular weight polyhydroxyl compound (a) or a mixture of (a) and a low molecular weight chain extender and/or crosslinker (b) with diphenylmethane 4,4'-diisocyanate in an equivalence ratio of the hydroxyl groups to isocyanate groups of 1:>1 to 6 to give a polyaddition product containing urethane and isocyanate groups and reacting this polyaddition product with naphthylene 1,5-diisocyanate in an equivalence ratio of hydroxyl groups of (a) or (a) and (b) to isocyanate groups of naphthylene 1,5-diisocyanate of 1:0.02-6 to form the prepolymer containing isocyanate groups. 12. A process for producing cellular polyurethane elastomers as claimed in any of claims 1 to 11, wherein the blowing agent (d) [sic] is selected from the group consisting of alkanes having from 4 to 8 carbon atoms, cycloalkanes having from 4 to 6 carbon atoms and water. 13. A prepolymer containing isocyanate groups, having an NCO content of from 3.3 to 10% by weight and prepared by reacting at least one polyhydroxyl compound with molecular weight 800-6000 (a) or a mixture of (a) chain extender and/or crosslinker with molecular weight up to 800 (b) with at least one 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 hexamethylene 1,6-diisocyanate and/or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane to give a polyaddition product containing urethane and isocyanate groups and having an NCO content of from 0.05 to 8% by weight and reacting this polyaddition product with naphthylene 1,5-diisocyanate to give the prepolymer containing isocyanate groups. 14. A prepolymer containing isocyanate groups as claimed in claim 13, wherein the equivalence ratio of the hydroxyl groups of (a) or (a) and (b) to NCO groups of the aromatic diisocyanates selected from the group consisting of tolylene diisocyanate, diphenylmethane diisocyanate, 3,3'-dimethylbiphenyl diisocyanate, 1,2-diphenylethane diisocyanate and phenylene diisocyanate, and/or hexamethylene 1,6-diisocyanate and/or 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, and NCO groups of naphthylene 1,5-diisocyanate is 1:>1 to 6:0.02-6. 15. A prepolymer containing isocyanate groups, having an NCO content of from 3.3 to 10% by weight and prepared by reacting at least one polyhydroxyl compound with molecular weight (a) or a mixture of (a) chain extender and/or crosslinker with molecular weight up to 800 (b) with diphenylmethane 4,4'-diisocyanate to give a polyaddition product containing urethane and isocyanate groups and having an NCO content of from 0.05 to 8% by weight and reacting this polyaddition product with naphthylene 1,5-diisocyanate to give the prepolymer containing isocyanate groups. 16. A prepolymer containing isocyanate groups, having an NCO content of from 3.3 to 10% by weight and prepared by reacting a difunctional polyhydroxyl compound having a molecular weight of from >800 to 3500 and selected from the group consisting of polyester polyols, hydroxyl-containing polycarbonates and polyoxytetramethylene glycols with diphenylmethane 4,4'-diisocyanate to give a polyaddition product containing urethane and isocyanate groups and reacting this polyaddition product with naphthylene 1,5-diisocyanate to give the prepolymer containing isocyanate groups. 17. A prepolymer containing isocyanate groups as claimed in claim 15 or 16, wherein the equivalence ratios of the hydroxyl groups of (a) or (a) and (b) to NCO groups of the diphenylmethane 4,4'-diisocyanate to NCO groups of the naphthylene 1,5-diisocyanate are 1:(>1 to 6):0.02-6.