LUBRICANTS WITH A TERPOLYMER MADE OF DIESTER, OLEFIN AND ACRYLATE

Abstract

Lubricants with a terpolymer made of diester, olefin and acrylate The invention relates to a lubricant comprising a terpolymer which comprises in polymerized forma diester selected from di(C.sub.4-C.sub.22 alkyl)ester of maleic acid, fumaric acid, 2-methylmaleic acid, 2,3-dimethylmaleic acid, 2-methylfumaric acid, 2,3-dimethylfumaric acid, or mixtures thereof, an olefin selected from C.sub.6-C.sub.40 alky-1-ene, and an acrylate selected from C.sub.4-C.sub.40 alkyl (meth)acrylate. The invention further relates to the terpolymer, a process for preparing the terpolymer comprising the step of polymerizing the diester, the olefin, and the acrylate; and to a method for reducing friction between moving surfaces comprising the step of contacting the surfaces with the lubricant or with the terpolymer.

Claims

1.-18. (canceled)

19. A lubricant comprising a terpolymer which comprises in polymerized form a diester selected from di(C.sub.4-C.sub.22 alkyl)ester of maleic acid, fumaric acid, 2-methylmaleic acid, 2,3-dimethylmaleic acid, 2-methylfumaric acid, 2,3-dimethylfumaric acid, or mixtures thereof, an olefin selected from C.sub.6-C.sub.40 alky-1-ene, and an acrylate selected from C.sub.4-C.sub.40 alkyl (meth)acrylate.

20. The lubricant according to claim 19 where the diester is selected from linear or branched di(C.sub.6-C.sub.14 alkyl)ester of maleic acid, fumaric acid, 2-methylmaleic acid, 2,3-dimethylmaleic acid, 2-methylfumaric acid, 2,3-dimethylfumaric acid, or mixtures thereof.

21. The lubricant according to claim 19 where the diester is selected from di(2-ethylhexyl)ester of maleic acid, fumaric acid, or mixtures thereof.

22. The lubricant according to claim 19 where the diester is selected from linear or branched di(C.sub.6-C.sub.14 alkyl)ester of maleic acid, 2-methylmaleic acid, 2,3-dimethylmaleic acid, 2-methylfumaric acid, 2,3-dimethylfumaric acid, or mixtures thereof.

23. The lubricant according to claim 19 where the olefin is selected from C.sub.6-C.sub.22 alky-1-ene.

24. The lubricant according to claim 19 where the acrylate is selected from linear or branched C.sub.4-C.sub.22 alkyl (meth)acrylate.

25. The lubricant according to claim 19 where the molar ratio of the diester to the olefin is from 3:1 to 1:2.

26. The lubricant according to claim 19 where the terpolymer comprises in polymerized form 5-40 mol % of the diester, 5-40 mol % of the olefin, and 20-90 mol % of the acrylate, where the amounts of the monomers sum up to 85 to 100 mol %.

27. The lubricant according to claim 19 where the terpolymer is obtainable by polymerizing the diester, the olefin, and the acrylate.

28. The lubricant according to claim 19 where the diester is selected from a mixture of di(C.sub.6-C.sub.10 alkyl)ester of maleic acid with di(C.sub.6-C.sub.10 alkyl)ester of fumaric acid.

29. The lubricant according to claim 19 where the terpolymer has a number-average molecular weight Mn from 500 to 15 000 g/mol.

30. The lubricant according to claim 19 where the terpolymer has a pour point below 10° C.

31. The lubricant according to claim 19 where the terpolymer has a cloud point of below 10° C.

32. The lubricant according to claim 19 where the terpolymer has a pour point below −10° C. and a cloud point of below −10° C.

33. The lubricant according to claim 19 where the terpolymer is miscible with a polyalphaolefine having a kinematic viscosity at 100° C. of about 6 cSt.

34. The lubricant according to claim 19, further comprising a base oil selected from mineral oils, polyalphaolefins, polymerized and interpolymerized olefins, alkyl naphthalenes, alkylene oxide polymers, silicone oils, phosphate ester and carboxylic acid ester; and/or a lubricant additive.

35. A terpolymer as defined in claim 19.

36. A process for preparing the terpolymer as defined in claim 19 comprising the step of polymerizing the diester, the olefin, and the acrylate.

37. A method for reducing friction between moving surfaces comprising the step of contacting the surfaces with the lubricant as defined in claim 19.

38. A method for reducing friction between moving surfaces comprising the step of contacting the surfaces with the terpolymer as defined in claim 35.

Description

EXAMPLES

[0159] DOM: bis (2-ethylhexyl) maleate, also known as “dioctyl maleate”, contains about 10-40 mol % of bis(2-ethylhexyl) fumarate. [0160] DOD: 1-dodecene, purity >95 wt %, 1-5 wt % 1-decene/1-tetradecene. [0161] Heptadecyl acrylate: acrylate based on mixture of branched C.sub.17 alcanols, commercially available from BASF SE. [0162] Heptadecyl methacrylate: methacrylate based on mixture of branched C.sub.17 alcanols, commercially available from BASF SE. [0163] Lauryl acrylate: a 60:40 mixture of C.sub.12:C.sub.14 alkyl acrylates. [0164] 2-Propylheptyl acrylate: commercially available from BASF SE. [0165] 2-Propylheptyl methacrylate: commercially available from BASF SE.

[0166] The molecular weight number distribution Mn and the molecular weight weight distribution Mw were determined via GPC. The polydispersity was calculated as PD=(Mw/Mn). The GPC analysis was made with a RI detector, a PLgel MIXED-B column (column temperature 35° C.) and THF with 0.1% trifluor acetic acid as elution medium. The calibration was done with very narrow distributed polystyrene standards from the Polymer Laboratories with a molecular weights M=from 580 until 6.870.000 g/mol.

[0167] The Cloud Point CP was determined according to ISO 3015. The Pour Point PP was determined according to ASTM D 97. The amounts of monomomers which are present in polymerized form in the polymer was determined by H-NMR.

Examples 1 to 17: Polymerization

[0168] The terpolymer which contained the monomers dioctyl maleate (“DOM”), 1-dodecene (“DOD”) and 2-ethylhexyl acrylate as described in Table 1 in a molar ratio of 1:1:1 was prepared as follows (see Example 2). The other polymers were prepared in the same manner. It was also possible to add 1/3 of the acrylate in the beginning to the DOM and DOD.

[0169] In a 2 Liter vessel with anchor stirrer were introduced as precharge the diester DOM (645 g) and the olefin DOD (315 g). The mixture was gassed with N.sub.2 and was heated until 155° C. As soon as the temperature was achieved about 85% of the initiator ditert. butylperoxide and 2-ethylhexyl acrylate (345.8 g) were added into the reaction mixture separately for 3 hours. Afterwards the system was kept under 1 hour at 145° C. Finally, the rest of the initiator ditert.-butylperoxide was added in one portion under 145° C. and after 2 hours the polymerization is finished. In total 1.41 weight % (based on the total amount of monomers) of the initiator was added. The product was yellowish and low viscous with solid contents >99.5 wt %. If the solid content was below 99 wt % a further clean step could be made, which could be either vacuum distillation at 145° C. or simply stripping with N.sub.2 at 145° C. and room pressure conditions.

TABLE-US-00001 TABLE 1 Composition and properties. Mn Mw PP CP Ex. Acrylate Ratio [g/mol] [g/mol] PD [° C.] [° C.] 1 n-butyl acrylate 1:1:2 3720 9700 2.6 −24 −55 2 2-ethylhexyl acrylate 1:1:1 2480 5270 2.1 −33 −64 3 2-ethylhexyl acrylate 1:1:0.5 2040 3920 1.9 −33 −61 4 2-ethylhexyl acrylate 1:1:3 2860 7610 2.7 −24 −55 5 2-ethylhexyl acrylate 1:1:6 3720 13700 3.7 −27 −58 6 2-ethylhexyl acrylate 1.75:1:0.5 1440 3050 2.1 −30 −61 7 2-ethylhexyl methacrylate 1:1:1 1710 3770 2.2 −33 −61 8 3-propylheptyl acrylate 1:1:1 2430 4910 2.0 −27 −10 9 3-propylheptyl methacrylate 1:1:1 1710 3600 2.1 −33 −60 10 Lauryl acrylate 1:1:1 2750 6070 2.2 −24 −23 11 Lauryl acrylate 1:1:2 3400 10700 3.1 −12 −14 12 Lauryl methacrylate 1:1:1 1950 4640 2.4 −36 −61 13 Lauryl methacrylate 1:1:3 3210 15900 4.9 −21 −50 14 Isoheptadecyl acrylate 1:1:1 2610 5360 2.1 −27 −57 15 Isoheptadecyl acrylate 1.5:1:0.5 1650 3600 2.2 −30 −58 16 Isoheptadecyl acrylate 1:1:5 2810 11400 4.1 −21 −50 17 Isoheptadecyl methacrylate 1:1:1 1880 4030 2.1 −30 −13 “Ratio” is the molar ratio diester:olefin:acrylate

[0170] The results demonstrated that all terpolymers were liquid at room temperature and had a pour point below 25° C. The results further indicate that all terpolymers tend to have good low temperature characteristics because of their low cloud point.

Example 18: Viscosity and Appearance

[0171] The Kinematic Viscosity at 40° C. (KV40) and at 100° C. (KV100) were determined according to ASTM D 445 and the values given as [mm.sup.2/s]. The Viscosity Index (VI) was determined according to ASTM D 2270. The appearance of the terpolymers was determined visually.

[0172] The results demonstrated that the terpolymers have a desired high kinematic viscosity, as well as a desired high viscosity index.

TABLE-US-00002 TABLE 2 Viscosities Ex. Acrylate Ratio KV40 KV100 VI Appearance 1 n-butyl acrylate 1:1:2 2380 174 188 Clear 2 2-ethylhexyl acrylate 1:1:1 1121 95 172 Clear 3 2-ethylhexyl acrylate 1:1:0.5 1003 82 161 Clear 4 2-ethylhexyl acrylate 1:1:3 1946 145 180 Clear 5 2-ethylhexyl acrylate 1:1:6 4790 305 205 Clear 6 2-ethylhexyl acrylate 1.75:1:0.5 1078 81 152 Clear 7 2-ethylhexyl 1:1:1 1007 73 144 Clear methacrylate 8 3-propylheptyl acrylate 1:1:1 1460 111 169 Clear 9 3-propylheptyl 1:1:1 794 64 147 Clear methacrylate 10 Lauryl acrylate 1:1:1 1037 91 173 Clear 11 Lauryl acrylate 1:1:2 1571 143 200 Clear 12 Lauryl methacrylate 1:1:1 612 57 159 Clear 13 Lauryl methacrylate 1:1:3 3886 256 198 Clear 14 Isoheptadecyl acrylate 1:1:1 1559 111 162 Clear 15 Isoheptadecyl acrylate 1.5:1:0.5 1086 82 152 Clear 16 Isoheptadecyl acrylate 1:1:5 4507 278 196 Clear 17 Isoheptadecyl 1:1:1 1034 75 144 Clear methacrylate

Example 19: Miscibility with Polyalphaolefins

[0173] The terpolymers were mixed with polyalphaolefine having a kinematic viscosity at 100° C. of about 6 cSt in a weight ratio of 50:50 at room temperature and mixed at room temperature by rolling for 12 hours. The mixtures' appearance was observed after homogenization and again after 24 hours. The copolymer is deemed compatible with the polyalphaolefine when no phase separation was observed after 24 hours.

[0174] The results in Table 3 demonstrated that the terpolymers a miscible with very unpolar low viscosity polyalphaolefines (typically based on poly(1-decen)).

TABLE-US-00003 TABLE 3 Miscibility with PAO-6 (50:50 vol %) Ex. Acrylate Ratio Miscible 2 2-ethylhexyl acrylate 1:1:1 Yes 4 2-ethylhexyl acrylate 1:1:3 Yes 7 2-ethylhexyl methacrylate 1:1:1 Yes 10 Lauryl acrylate 1:1:1 Yes 12 Lauryl methacrylate 1:1:1 Yes 13 Lauryl methacrylate 1:1:3 Yes 16 Isoheptadecyl acrylate 1:1:5 Yes

Example 20: Thermal Oxidative Stability

[0175] The thermal oxidative stability RPVOT was tested according to ASTM D2272. This standard test utilizes an oxygen-pressured vessel to evaluate the oxidation stability oils in the presence of water and a copper catalyst coil at 150° C. The time (minutes) was measured until the pressure decreases for 175 kPa below the maximum. The longer it takes, the more resistant the oil is against oxidation. All samples contained 0.5 wt % of the Irganox® L06, an octylated phenylalpha-naphthylamine commercially available from BASF SE.

TABLE-US-00004 TABLE 4 Ex. Acrylate Ratio RPVOT [min] 2 2-ethylhexyl acrylate 1:1:1 1529 3 2-ethylhexyl acrylate 1:1:0.5 1319 8 3-propylheptyl acrylate 1:1:1 1078 10 Lauryl acrylate 1:1:1 1123 11 Lauryl acrylate 1:1:2 2083 13 Lauryl methacrylate 1:1:3 1199 14 Isoheptadecyl acrylate 1:1:1 702

Example 21: Lubricant Formulations

[0176] The lubricant formulations A to E were prepared by mixing the components according Table 5. The lubricant formulations are suitable as gear oils.

[0177] The data demonstrated that lubricant formulations combine excellent properties, such as high viscosity index, a low pour point, oxidative stability, and a low shear loss.

TABLE-US-00005 TABLE 5 A B C D E Terpolymer type Ex. 2 Ex. 4 Ex. 5 Ex. 4 Ex. 4 Terpolymer amount  79.8%  66.2% 57.4%  66.2%  68.1% PAO-6  17.5%  31.2% 39.9% —  19.5% Mineral Oil — — —  31.2% — Synative ® ES — — — —   9.7% DPHA HiTEC ® 307   2.7%   2.7%  2.7%   2.7%   2.7% KV40 [mm.sup.2/s]   323   311   325   313   303 KV100 [mm.sup.2/s]    34    35    38    35    35 VI   149   157   168   155   162 Pour Point [° C.]  −42  −42  −39  −30  −45 ASTM D2893A  13.4%   7.0%  2.0%   6.8%   5.5% KRL100 h  <1%  <1%  8.9%  <1%  <1% HiTEC ® 307: An industrial gear oil additive package, clear dark amber liquid, KV 100 13 cSt, commercially available from Afton Chemical Corp., USA. Synative ® ES DPHA: A base oil made of di-(2-propylheptyl) adipate, commercially available from BASF SE, Germany. PAO-6: A polyalphaolefin base oil, KV100 6 cSt. Mineral Oil: a mineral oil from Group III base oils, KV 100 6 cSt. ASTM D2893A: This test method is widely used to determine the oxidation stability of extreme pressure lubricating fluids, gear oils, and mineral oils. The oil sample was subjected to a temperature of 121° C. in the presence of dry air for 312 h. The oil was then tested for increase in KV100 and the result was given as percentage of increase. KRL 100 h: This test method is used to evaluate the shear loss, and was calculated by the KV100 before and after the test according to CEC L-45-99.