METHOD FOR PRODUCING HYDROGENATED NITRILE RUBBER AND HNBR COMPOSITIONS THEREOF

Abstract

The present invention relates to a method for producing hydrogenated nitrile rubber (HNBR) having good ageing properties in the presence of ruthenium, palladium or rhodium compounds and also to the hydrogenated nitrile rubber produced by this method and HNBR compositions thereof.

Claims

1. Method for producing hydrogenated nitrile rubber (HNBR) comprising repeat units of at least 40% to 90% by weight of a conjugated diene and at least 10% to 60% by weight of an α,β-unsaturated nitrile, comprising subjecting at least partially unsaturated nitrile rubber (NBR) in solution comprising a ruthenium compound or a palladium compound or a rhodium compound to hydrogenation, wherein: the amount of ruthenium, based on the at least partially unsaturated nitrile rubber, is 10 ppm to 200 ppm, 10 ppm to 150 ppm, 10 ppm to 120 ppm, 10 ppm to 79 ppm, or preferably 42 ppm to 79 ppm, or the amount of palladium, based on the at least partially unsaturated nitrile rubber, is 20 ppm to <67 ppm or 44 ppm to <67 ppm, or the amount of rhodium, based on the at least partially unsaturated nitrile rubber, is 50 ppm to <270 ppm, 79 ppm to <270 ppm, 50 ppm to 250 ppm, 50 ppm to 170 ppm, and or 79 ppm to 170 ppm, wherein the hydrogenation is effected at a temperature of 60 to 200° C., at a pressure of 700 000 pascals to 15 000 000 pascals, and for a period of 1 to 24 hours, wherein the ruthenium compounds are selected from the group consisting of carbonylchlorohydridotris(triphenylphosphine)ruthenium(II), (RuHCl(CO)(PPh.sub.3).sub.3), benzylidenebis(tricyclohexylphosphine)dichlororuthenium (first-generation Grubbs catalyst), benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro(tricyclohexylphosphine)ruthenium (second-generation Grubbs catalyst), dichloro(o-isopropoxyphenylmethylene)(tricyclohexylphosphine)ruthenium(II) (first-generation Hoveyda-Grubbs catalyst), 1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxyphenylmethylene)ruthenium (second-generation Hoveyda-Grubbs catalyst), or dichloro(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)((5-((dimethylamino)sulfonyl)-2-(1-methylethoxy-O)phenyl)methylene-C)ruthenium(II) (Zhan catalyst-1B), or are selected from a compound of the general formula (R.sup.1.sub.mB).sub.lMX.sub.n, in which M is ruthenium or rhodium, R.sup.1 are identical or different and are a C.sub.1-C.sub.8 alkyl group, a C.sub.4-C.sub.8 cycloalkyl group, a C.sub.6-C.sub.15 aryl group or a C.sub.7-C.sub.15 aralkyl group. B is phosphorus, arsenic, sulfur or a sulfoxide group (S═O), X is hydrogen or an anion, halogen, chlorine, or bromine, l is 2, 3 or 4, m is 2 or 3 and n is 1, 2 or 3, wherein the palladium compounds are selected from palladium acetate, palladium cyanate, palladium fluoride, palladium chloride, palladium bromide, palladium iodide, palladium nitrate, palladium sulfate, palladium oxide, palladium hydroxide, dichloro(cyclooctadiene)palladium, dichloro(norbornadiene)palladium, tetrakis(acetonitrile)palladium tetrafluoroborate, tetrakis(benzonitrile)palladium ditetrafluoroborate, dichlorobis(acetonitrile)palladium, dichlorobis(ethylenediamine)palladium, bis(acetylacetonato)palladium, tris(triphenylphosphine)acetonitrilepalladium tetrafluoroborate, dichlorobis(triethylphosphine)palladium, dichlorobis(dimethyl sulfide)palladium, dibenzoylsulfidepalladium, bis(2,2′-bipyridine)palladium perchlorate, or tetrakis(pyridine)palladium dichloride, wherein the rhodium compounds are selected from rhodium chloride, rhodium bromide, rhodium iodide, rhodium nitrate, rhodium sulfate, rhodium acetate, rhodium formate, rhodium propionate, rhodium butyrate, rhodium valerate, rhodium naphthenate, rhodium oxide, rhodium trihydroxide; dichlorobis(triphenylphosphine)rhodium, trichlorotris(pyridine)rhodium, tetrarhodium dodecacarbonyl, dirhodium octacarbonyl, hexarhodium hexadecacarbonyl, rhodium dicarbonyl acetylacetonate, rhodium carbonyl (1-phenylbutane-1,3-dione), tris(hexane-2,4-dione)rhodium, tris(heptane-2,4-dione)rhodium, tris(1-phenylbutane-1,3-dione)rhodium, tris(3-methylpentane-2,4-dione)rhodium, tris(1-cyclohexylbutane-1,3-dione)rhodium, or [Rh(OAc).sub.2].sub.2, or are selected from a compound of the general formula (R.sup.1.sub.mB).sub.lMX.sub.n, in which M is rhodium, R.sup.1 are identical or different and are a C.sub.1-C.sub.8 alkyl group, a C.sub.4-C.sub.8 cycloalkyl group, or a C.sub.7-C.sub.15 aralkyl group, B is phosphorus, arsenic, sulfur or a sulfoxide group (S═O), X is hydrogen or an anion, halogen, chlorine, or bromine, l is 2, 3 or 4, m is 2 or 3 and n is 1, 2 or 3, and wherein no step for removing ruthenium, palladium or rhodium takes place after hydrogenation.

2. Method according to claim 1, wherein the hydrogenation is effected at a temperature of 100 to 150° C. or at 100 to 140° C.

3. Method according to claim 1, wherein the hydrogenation is effected at a pressure of 5 000 000 pascals to 10 000 000 pascals.

4. Method according to claim 1, wherein the hydrogenation is effected for a period of 1.5 to 12 hours.

5. Method according to claim 1, wherein the hydrogenation is conducted in an organic solvent or in an organic solvent selected from the group consisting of benzene, toluene, cyclohexane, dimethyl sulfoxide (DMSO), ethylene carbonate (EC), tetrahydrofuran (THF), 1,4-dioxane, monochlorobenzene (MCB), dichlorobenzene (DCB), trichlorobenzene (TCB), monobromobenzene (MBB), dibromobenzene (DBB), tribromobenzene (TBB), methyl ethyl ketone (MEK), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), methyl ethyl ketone, or mixtures thereof.

6. HNBR compositions obtainable by the method of claim 1, comprising hydrogenated nitrile rubber, comprising repeat units of at least 40% to 90% by weight of a conjugated diene and at least 10% to 60% by weight of an α,β-unsaturated nitrile, and 10 ppm to 200 ppm, 10 ppm to 150 ppm, 10 ppm to 120 ppm, 10 ppm to 79 ppm, or 42 ppm to 79 ppm of ruthenium, or 20 ppm to <67 ppm, or 44 ppm to <67 ppm of palladium, or 50 ppm to <270 ppm, 50 ppm to 250 ppm, 50 ppm to 240 ppm, 50 ppm to 170 ppm, or 79 ppm to 170 ppm of rhodium, based on the hydrogenated nitrile rubber, wherein the Mooney viscosity (ML(1+4), 100° C.) of the hydrogenated nitrile rubbers, measured as per ASTM Standard D 1646, is in the range from 10 to 120, and the Mooney viscosity increases by less than 40% during ageing of the hydrogenated nitrile rubbers for 4 days at 140° C., and wherein the hydrogenated nitrile rubbers obtained have a polydispersibility PDI 0 Mw7Mn, where Mw is the weight-average and Mn the number-average molecular weight, in a range of from 1 to 6.

7. Vulcanizable HNBR composition comprising (a) HNBR composition according to claim 6 and (b) at least one cross-linker, or at least one peroxidic compound.

8. Method for producing vulcanizable a HNBR compositions according to claim 7 comprising mixing an HNBR composition with at least one cross-linker, or a peroxidic compound, wherein the HNBR composition comprises hydrogenated nitrile rubber, comprising repeat units of at least 40% to 90% by weight of a conjugated diene and at least 10% to 60% by weight of an α,β-unsaturated nitrile, and 10 ppm to 200 ppm, 10 ppm to 150 ppm, 10 ppm to 120 ppm, 10 ppm to 79 ppm, or 42 ppm to 79 ppm of ruthenium, or 20 ppm to <67 ppm or 44 ppm to <67 ppm of palladium, or 50 ppm to <270 ppm, 50 ppm to 250 ppm, 50 ppm to 240 ppm, 50 ppm to 170 ppm, or 79 ppm to 170 ppm of rhodium, based on the hydrogenated nitrile rubber, wherein the Mooney viscosity (ML(1+4), 100° C.) of the hydrogenated nitrile rubbers, measured as per ASTM Standard D 1646, is in the range from 10 to 120, and the Mooney viscosity increases by less than 40% during ageing of the hydrogenated nitrile rubbers for 4 days at 140° C., and wherein the hydrogenated nitrile rubbers obtained have a polydispersibility PDI 0 Mw7Mn, where Mw is the weight-average and Mn the number-average molecular weight, in a range of from 1 to 6.

9. Method for producing vulcanizates, comprising subjecting the vulcanizable HNBR composition according to claim 7 to a vulcanization, in a shaping process and at temperatures in the range from 100° C. to 250° C., from 120° C. to 250° C., or from 130° C. to 250° C.

10. Vulcanizates based on a vulcanizable HNBR compositions according to claim 7, obtainable by subjecting the vulcanizable HNBR composition to a vulcanization in a shaping process and at temperatures in the range from 100° C. to 250° C., from 120° C. to 250° C., or from 130° C. to 250° C.

11. Method of producing mouldings selected from the group consisting of belts, seals, rollers, shoe components, hoses, damping elements, stators, cable sheaths, belts, and seals with the HNBR composition according to claim 6.

Description

EXAMPLES

Materials Used

[0119]

TABLE-US-00001 Therban ® 3627 hydrogenated nitrile rubber, 36% by weight acrylonitrile units; Mooney viscosity ML 1 + 4@100° C.: 66; gel content: 0.7%, noble metal content: 2 ppm of rhodium, <1 ppm of ruthenium, <1 ppm of palladium; (commercially available from ARLANXEO Deutschland GmbH) Acetone propan-2-one (commercially available from Merck) Ethanol (commercially available from Merck) RuCl.sub.3 ruthenium trichloride (commercially available from Merck) [RuHCl(CO)(PPh.sub.3).sub.3] carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) (commercially available from Merck) [Pd(OAc).sub.2].sub.3 palladium acetate (commercially available from Merck) [Rh(OAc).sub.2].sub.2 rhodium acetate (commercially available from Merck) [Rh(PPh.sub.3).sub.3Cl] chloridotris(triphenylphosphine)rhodium(I); Wilkinson's catalyst (commercially available from Umicore)

Mooney Ageing

[0120] In order to assess Mooney ageing, the change in the Mooney viscosity was measured after an exemplary ageing process. The values for the Mooney viscosity (ML1+4@100° C.) are determined in each case by means of a shearing disc viscometer in accordance with ASTM D1646-07. Two test specimens are cut out of the rubber. The specimen to be aged is placed into an air circulation drying cabinet, heated to 140° C., on the middle rack. The specimens remain there for 4 days at 140° C.

[0121] The Mooney viscosity is determined on the unaged and the aged specimens. AMV results from the difference in the measured values of the aged and the unaged specimen.

Gel Content

[0122] 0.1-0.2 g of the polymer is dispersed, or rather the soluble polymer fractions are dissolved, in approximately 20 ml of methyl ethyl ketone (MEK). After 18 hours, the insoluble dispersed fractions are precipitated by centrifugation (25 000 rpm), the supernatant solvent is decanted, the moist gel remaining is weighed, dried thereafter to constant weight at 60° C. in a vacuum drying cabinet, and weighed again.

[0123] The percentage gel content is calculated from the difference in weight between the soluble and the insoluble polymer.

Performance of Ageing Investigations:

[0124] The influence of ruthenium, palladium and rhodium compounds on the ageing of hydrogenated nitrile rubber was investigated. To this end, in Examples 1 to 17, hydrogenated nitrile rubber was dissolved and admixed with ruthenium, palladium or rhodium compounds and aged. Specifically, Therban® 3627 (with a noble metal content of 2 ppm of rhodium, <1 ppm of ruthenium and <1 ppm of palladium) was dissolved in acetone (10%) (exception: [Rh(OAc).sub.2].sub.2 was dissolved in ethanol) and admixed with the calculated amount of ruthenium, palladium or rhodium compound. After 2 hours of mixing on a shaker, the solution was plated and dried in a vacuum drying cabinet at 55° C. to constant weight. Subsequently to this, the dried HNBR compositions were aged for 4 days at 140° C.

TABLE-US-00002 TABLE 1 Comparison of the results of the gel content and Mooney viscosity prior to ageing and after ageing for 4 days at 140° C. Polymer prior to ageing Polymer after ageing Noble (4 d, 140° C.) metal Gel Mooney Gel Mooney Ex. addition content viscosity content viscosity ΔMV no. Noble metal [ppm] [%] [MU] [%] [MU] [MU] 1 Reference — 0.7 66 4.7 81 15 2 RuHCl(CO)(PPh.sub.3).sub.3 42 0.6 67 5.1 78 11 3 RuHCl(CO)(PPh.sub.3).sub.3 79 0.6 68 7.0 82 14 4 RuHCl(CO)(PPh.sub.3).sub.3 120 0.6 69 7.7 80 11 5 RuHCl(CO)(PPh.sub.3).sub.3 150 0.8 69 4.2 79 10 6 RuHCl(CO)(PPh.sub.3).sub.3 200 0.8 69 5.2 78 8 7 Pd(OAc).sub.2 44 0.8 68 9.2 91 23 8 Pd(OAc).sub.2 67 0.9 68 11.2 83 15 9 Pd(OAc).sub.2 100 0.5 69 12.6 105 36 10 Pd(OAc).sub.2 120 0.5 69 16.7 129 60 11 Pd(OAc).sub.2 150 0.8 68 17.1 115 47 12 Pd(OAc).sub.2 210 0.7 76 17.6 174 99 13 [Rh(OAc).sub.2].sub.2 79 0.7 67 4.2 88 22 14 [Rh(OAc).sub.2].sub.2 170 0.8 67 5.5 91 24 15 [Rh(OAc).sub.2].sub.2 240 0.9 67 5.6 99 32 16 [Rh(OAc).sub.2].sub.2 270 0.8 66 8.0 106 41 17 [Rh(OAc).sub.2].sub.2 280 0.7 66 6.5 108 41

[0125] Ruthenium compounds have only a small influence on the ageing of the hydrogenated nitrile rubber in a range from 10 ppm to 200 ppm. After 4 days of ageing at 140° C., the gel content is below 10% and the increase in the Mooney viscosity is less than 20 MU.

[0126] Palladium compounds have only a small influence on the ageing of the hydrogenated nitrile rubber in a range from 20 ppm to <67 ppm. After 4 days of ageing at 140° C., the gel content is below 10% and the increase in the Mooney viscosity is less than 40 MU. If the content of palladium in the HNBR is 100 ppm or more, there is a marked increase in gel formation over the course of the ageing and also in the amount by which the Mooney viscosity rises.

[0127] Rhodium compounds have only a small influence on the ageing of the hydrogenated nitrile rubber in a range from 50 ppm to <270 ppm. After 4 days of ageing at 140° C., the gel content is below 10% and the increase in the Mooney viscosity is less than 40 MU. If the content of rhodium in the HNBR is 270 ppm or more, there is a marked increase in the amount by which the Mooney viscosity rises.