COMPOSITION OF CURABLE POLYURETHANE PREPOLYMER

Abstract

The present invention relates in general to a curable polyurethane prepolymer composition comprising a polyurethane prepolymer obtained by the reaction of toluene diisocyanate (TDI) and at least one polyol and an ortho-alkyl disubstituted dianiline, preferably 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA), wherein 50 to 100% by weight of the at least one polyol is at least one polycarbonate polyol.

Claims

1. A curable polyurethane prepolymer composition comprising: a polyurethane prepolymer obtained by the reaction of toluene diisocyanate and at least one polyol, and a disubstituted orthoalkyl dianiline, wherein 50 to 100% by weight of the at least one polyol is at least one polycarbonate polyol.

2. The composition according to claim 1, wherein the disubstituted orthoalkyl dianiline is a compound of general formula (I) Formula (I) wherein R1 represents independent linear or branched Ci-Ce alkyl and R2 represents hydrogen or halogen, preferably F, Cl, Br or I, more preferably Cl, and A represents -O-, -CH2-, -C(CH3)2-, -SO2- or -CO2(CH2)nO2C wherein n represents 1, 2, 3, 4, 5 or 6 3. The composition according to claim 1 or 2, wherein the disubstituted orthoalkyl dianiline is selected from a group consisting of 4,4'-methylenebis-(3-chloro-2,6-diethylaniline) (MCDEA), 4,4'-methylenebis-(2,6-diethylaniline), 4,4'-methylenebis-(2,6-diisopropylaniline) and 4,4'-methylenebis-(2-methyl-6-isopropylaniline), or mixtures thereof.

4. The composition according to any of claims 1 to 3, wherein the disubstituted orthoalkyl dianiline is 4,4' methylene-bis-(3-chloro-2,6 diethylaniline).

5. The composition according to any of claims 1 to 4, wherein the at least one polycarbonate polyol comprises poly(hexamethylene carbonate)diol 6. The composition according to any of claims 1 to 5, wherein the toluene diisocyanate is a mixture of toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.

7. The composition according to any of claims 1 to 6, wherein the molar ratio of the polyurethane prepolymer to the curing agent is in the range of 0.5:1 to 1.5:1, preferably 0.7:1 to 1.2:1 and more preferably 0.85:1 to 1.1:

1.

8. The composition according to any of claims 1 to 7, wherein the polyurethane prepolymer has a free NCO content (% NCO) not exceeding 8.5% NCO, more preferably from 1.0% by weight to 8.0% by weight and even more preferably from 2.0% by weight to 8.0% by weight.

9. The composition according to any of claims 1 to 8, wherein the polyurethane prepolymer comprises less than 0.1% by weight of free TDI monomer, based on the total weight of the polyurethane prepolymer.

10. The composition according to any of claims 1 to 9, wherein at least one polyol is poly(hexamethylene carbonate)diol and the disubstituted orthoalkyl dianiline is 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline).

11. A process for preparing a polyurethane elastomer, comprising: reacting the polyurethane prepolymer and the curing agent of the curable polyurethane prepolymer composition according to any of claims 1 to 10 to form a polyurethane elastomer.

12. A polyurethane elastomer prepared according to the procedure of claim 11. frLnLLn / zznz / e / Ywi 13. An article, preferably a mud pump piston, header ring, seal, valve seat, power transmission belt, wheels, roller, bushing or bearing intended for high temperature applications, comprising the polyurethane elastomer of claim 12. 5 14. Use of an article according to claim 13 at a temperature of 100-150 °C.