High-value polyurethane elastomers and production thereof

1. A process for producing a low-viscosity NCO prepolymer based on naphthalene 1,5-diisocyanate, comprising:

a) reacting naphthalene 1,5-diisocyanate (NDI) with which from 0.05 to 0.7% by weight, based on component b), of naphthyl 1-isocyanate has been admixed continuously or batchwise with

b) at least one polyol which has a number-average molar mass of from 850 to 3000 g/mol, viscosity of ≦2500 mPas measured at 120° C., and functionality of from 1.95 to 2.15, selected from the group consisting of polyester polyols, poly-ε-caprolactone polyols, polycarbonate polyols, polyether polyols, and α-hydro-ω-hydroxy-poly(oxytetramethylene) polyols, wherein the polyol is at a temperature of from 80° C. to 240° C.

in a ratio of NCO groups to OH groups of from 1.5:1 to 3.05:1.

2. A process for producing a polyurethane elastomer, wherein the NCO prepolymer produced by the process as claimed in claim 1 , based on naphthalene 1,5-diisocyanate, is reacted with

c) a chain extender which has hydroxy groups, a molecular weight of from 62 to 450 daltons, and functionality of from 2 to 3, and/or water,

d) optionally in the presence of a blowing agent, an auxiliary, and/or an additive.

3. A low-viscosity NCO prepolymer based on naphthalene 1,5-diisocyanate obtained from

a) naphthalene 1,5-diisocyanate (NDI) with which from 0.05 to 0.7% by weight, based on component b), of naphthyl 1-isocyanate has been admixed and

b) at least one polyol which has a number-average molar mass of from 850 to 3000 g/mol, viscosity of ≦2500 mPas measured at 120° C., and functionality of from 1.95 to 2.15, selected from the group consisting of polyester polyols, poly-ε-caprolactone polyols, polycarbonate polyols, polyether polyols, and α-hydro-ω-hydroxy-poly(oxytetramethylene) polyols

in a ratio of NCO groups to OH groups of from 1.5:1 to 3.05:1.

4. A polyurethane elastomer obtained from an NCO prepolymer based on naphthalene 1,5-diisocyanate as claimed in claim 3 and from

c) a chain extender which has hydroxy groups, a molecular weight of from 62 to 450 daltons, and a functionality of from 2 to 3, and/or water,

d) optionally in the presence of a blowing agent, an auxiliary, and/or an additive.

5. A damping element in vehicle construction, an emergency wheel located on a wheel rim, or a coating for a roller, wheel, or roll comprising the polyurethane elastomer as claimed in claim 4 .

6. A process as claimed in claim 1 , wherein the polyol has a number-average molar mass of from 1000 to 3000 g/mol.

7. A process as claimed in claim 1 , wherein the polyol is a polyethylene adipate having an OH number of 55 and a functionality of 2.

8. A process as claimed in claim 1 , wherein the ratio of NCO groups to OH groups is from 1.7:1 to 2.85:1.

9. A process as claimed in claim 2 , wherein the chain extender is 1,4-butanediol.

10. An NCO prepolymer as claimed in claim 3 obtained from a polyol which has a number-average molar mass of from 1000 to 3000 g/mol.

11. An NCO prepolymer as claimed in claim 3 obtained from a polyol which is a polyethylene adipate having an OH number of 55 and a functionality of 2.

12. A polyurethane elastomer obtained from an NCO prepolymer as claimed in claim 10 and from

c) a chain extender which has hydroxy groups, a molecular weight of from 62 to 450 daltons, and a functionality of from 2 to 3, and/or water,

d) optionally in the presence of a blowing agent, an auxiliary, and/or an additive.

13. A polyurethane elastomer obtained from an NCO prepolymer as claimed in claim 11 and from

c) a chain extender that is 1,4-butanediol and/or water,

d) optionally in the presence of a blowing agent, an auxiliary, and/or an additive.