LUBRICATING COMPOSITION WITH PHASE-CHANGE MATERIAL

Abstract

Disclosed is a monophasic lubricating composition including a base oil, an oil chosen from the polyalkylene glycols (PAG) and a phase-change material, in particular water. The monophasic lubricating composition can be used, in particular, for lubricating a vehicle engine. It has improved thermal performance relative to the lubricant compositions of the prior art. It also helps reduce fouling of the engine parts.

Claims

1-13. (canceled)

14. A monophasic lubricating composition suitable for lubrication of an engine, comprising: a base oil, an oil selected from among polyalkylene glycols (PAGs), and 0.1 to 5 weight % of phase-change material relative to the amount of PAG.

15. The monophasic lubricating composition according to claim 14, wherein the composition comprises: a base oil and a mixture of an oil selected from among PAGs with a phase-change material; or a base oil and a solution of an oil selected from among PAGs with a phase-change material.

16. The monophasic lubricating composition according to claim 14, wherein the PAG is a block polymer of formula (I) or a statistical polymer of formula (I): ##STR00009## where: R.sup.1 is a straight-chain or branched C.sub.1-C.sub.30-alkyl group; n is an integer ranging from 2 to 60; R.sup.2 and R.sup.3, the same or different, are each independently a hydrogen atom or C.sub.1-C.sub.2-alkyl group.

17. The monophasic lubricating composition according to claim 14, wherein the PAG is selected from among: a block polymer of formula (IA) or a statistical polymer of formula (IA): ##STR00010## where: R.sup.1 is a straight-chain or branched C.sub.1-C.sub.30-alkyl group; m is an integer ranging from 2 to 60; R.sup.4 and R.sup.5 are a hydrogen atom; or R.sup.4 is a hydrogen atom and R.sup.5 is a methyl group; or R.sup.4 is a methyl group and R.sup.5 is a hydrogen atom; or R.sup.4 and R.sup.5 are a methyl group; or R.sup.4 is an ethyl group and R.sup.5 is a hydrogen atom; or R.sup.4 is a hydrogen atom and R.sup.5 is an ethyl group; a block polymer of formula (IB) or a statistical polymer of formula (IB): ##STR00011## where: R.sup.1 is a straight-chain or branched C.sub.1-C.sub.30-alkyl group; p and q are each independently an integer ranging from 1 to 30; R.sup.6 and R.sup.7 are a hydrogen atom; or R.sup.6 is a hydrogen atom and R.sup.7 is a methyl group; or R.sup.6 is a methyl group and R.sup.7 is a hydrogen atom; or R.sup.6 and R.sup.7 are a methyl group; or R.sup.6 is an ethyl group and R.sup.7 is a hydrogen atom; or R.sup.6 is a hydrogen atom and R.sup.7 is an ethyl group; R.sup.8 and R.sup.9 are a hydrogen atom; or R.sup.8 is a hydrogen atom and R.sup.9 is a methyl group; or R.sup.8 is a methyl group and R.sup.9 is a hydrogen atom; or R.sup.8 and R.sup.9 are a methyl group; or R.sup.8 is an ethyl group and R.sup.9 is a hydrogen atom; or R.sup.8 is a hydrogen atom and R.sup.9 is an ethyl group.

18. The monophasic lubricating composition according to claim 14, wherein the PAG is selected from among: a block polymer of formula (II) or a statistical polymer of formula (II): ##STR00012## where: R.sup.1 is a straight-chain or branched C.sub.8-C.sub.12-alkyl group; p is an integer ranging from 4 to 5; q is an integer ranging from 2 to 3; or a block polymer of formula (III) or a statistical polymer of formula (III): ##STR00013## where: R.sup.1 is a straight-chain or branched C.sub.8-C.sub.12-alkyl group; p is an integer ranging from 2 to 6; q is an integer ranging from 2 to 5.

19. The monophasic lubricating composition according to claim 14, wherein the phase-change material has a liquid-gas phase change.

20. The monophasic lubricating composition according to claim 14, wherein the phase-change material has an enthalpy of vaporization or latent heat of vaporization, measured at 100° C. and under 0.101 MPa, ranging from 800 to 3 500 kJ/kg.

21. The monophasic lubricating composition according to claim 14, wherein the phase-change material has a boiling point at normal pressure ranging from 50 to 150° C.

22. The monophasic lubricating composition according to claim 14, wherein the phase-change material is selected from among water, carboxylic acids, ethers, alcohols, short-chain alcohols, C.sub.1-C.sub.8 alcohols.

23. The monophasic lubricating composition according to claim 14, wherein the composition comprises 0.5 to 2 weight % of phase-change material relative to the amount of PAG.

24. The monophasic lubricating composition according to claim 14, wherein the composition comprises 1 to 30 weight % of phase-change material and PAG relative to the total amount of lubricating composition.

25. The monophasic lubricating composition according to claim 14, wherein the composition is prepared with a method comprising: preparing a mixture or a solution comprising an oil selected from among polyalkylene glycols (PAGs), and a phase-change material; adding this mixture or this solution to a base oil.

26. A method for lubrication of a motor vehicle engine, comprising: providing the monophasic lubricating composition of claim 14; and applying the monophasic lubricating composition to internal surfaces of the motor vehicle engine.

Description

EXAMPLE 1

Preparation of a Lubricating Composition (CL-1) of the Invention Comprising Water and a PAG (PAG-1)

[0114] ##STR00007##

PAG-1: R.sup.1=straight-chain alkyl derived from a C.sub.12,1 alcohol p=5.1 q=3.9

[0115] A monophasic lubricating composition of the invention (CL-1) was prepared from a mixture of water and a polyalkylene-glycol (PAG-1: commercial product Ucon OSP 32 produced by Dow) by mixing 1 g of water in 99 g of PAG-1. PAG-1 was prepared according to the method in Example 1 of international patent application WO-2013/164449 and comprises about 57 weight % of propylene oxide repeating units and about 43 weight % of butylene oxide repeating units. Its mean molar mass (measured as per standard ASTM D4274) is about 760 g.mol.sup.−1, its viscosity measured at 40° C. (as per standard ASTM D445) is 32 mm.sup.2.s.sup.−1, its viscosity measured at 100° C. (as per standard ASTM D445) is 6.1 mm.sup.2.s.sup.−1 and its viscosity index (measured as per standard ASTM D2270) is 149.

[0116] 15 g of a mixture of water and PAG-1 were then added to a formulated engine oil comprising: 13.3% additive package marketed under the name P6660 by Infineum, 5.3% hydrogenated polydiene polymer marketed under the name SV261 by Infineum, 0.3% PPD (Pour Point Depressant) marketed under the name LZ7748 by Lubrizol and 81.1% Group III base oils marketed under the name Nexbase 3043 (78%) and Nexbase 3050 (3.1%) by Neste.

EXAMPLE 2

Preparation of a Lubricating Composition of the Invention (CL-2) Comprising Water and a PAG (PAG-2)

[0117] ##STR00008##

PAG-2: R.sup.1=straight-chain alkyl derived from a C.sub.11,9 alcohol p=4.4 q=2.2

[0118] A monophasic lubricating composition of the invention (CL-2) was prepared from a mixture of water and a polyalkylene-glycol (PAG-2: commercial product Dowfax 20A42EB by Dow) by mixing 1 g of water in 99 g of PAG-2. PAG-2 comprises about 66 weight % of propylene oxide repeating units and about 34 weight % of ethylene oxide repeating units. Its mean molar mass (measured as per standard ASTM D4274) is about 535 g.mol.sup.−1, its viscosity at 40° C. (as per standard ASTM D445) is 32 mm.sup.2.s.sup.−1, its viscosity measured at 100° C. (as per standard ASTM D445) is 7 mm.sup.2.s.sup.−1 and its viscosity index (measured as per standard ASTM D2270) is 189.

[0119] 14 g of a mixture of water and PAG-2 were then added to a formulated engine oil comprising: 13.3% additive package marketed under the name P6660 by Infineum, 5.3% hydrogenated polydiene polymer marketed under the name SV261 by Infineum, 0.3% PPD (Pour Point Depressant) marketed under the name LZ7748 by Lubrizol and 81.1% Group III base oils marketed under the name Nexbase 3043 (78%) and Nexbase 3050 (3.1%) by Neste.

EXAMPLE 3

Preparation of a Comparative Lubricating Composition (CC-1) Comprising a PAG (PAG-1)

[0120] A comparative lubricating composition (CC-1) was prepared comprising: 13.3% additive package marketed under the name P6660 by Infineum, 5.3% hydrogenated polydiene polymer marketed under the name SV261 by Infineum, 0.3% PPD (Pour Point Depressant) marketed under the name LZ7748 by Lubrizol and 81.1% Group III base oils marketed under the name Nexbase 3043 (78%) and Nexbase 3050 (3.1%) by Neste. The PAG-1 was added in an amount of 15 weight % to the lubricating composition.

EXAMPLE 4

Preparation of a Comparative Lubricating Composition (CC-2) Comprising a PAG (PAG-2)

[0121] A comparative lubricating composition (CC-2) was prepared comprising: 13.3% additive package marketed under the name P6660 by Infineum, 5.3% hydrogenated polydiene polymer marketed under the name SV261 by Infineum, 0.3% PPD (Pour Point Depressant) marketed under the name LZ7748 by Lubrizol and 81.1% Group III base oils marketed under the name Nexbase 3043 (78%) and Nexbase 3050 (3.1%) by Neste. The PAG-2 was added in an amount of 14 weight % to the lubricating composition.

EXAMPLE 5

[0122] Evaluation of the Properties of the Lubricating Compositions of the Invention (CL-1) and CL-2), of the properties of a reference lubricating composition (CR-1) and of Comparative Lubricating Compositions (CC-1 et CC-2)

[0123] The reference lubricating composition (CR-1) was formed of 13.3% additive package marketed under the name P6660 by Infineum, 5.3% hydrogenated polydiene polymer marketed under the name SV261 by Infineum, 0.3% PPD (Pour Point Depressant) marketed under the name LZ7748 by Lubrizol and 81.1% Group III base oils marketed under the name Nexbase 3043 (78%) and Nexbase 3050 (3.1%) by Neste.

[0124] Each lubricating composition (10 Kg) was evaluated with a motor vehicle cleanliness test for diesel engine with common rail injection. The engine displacement was 1.4 L with 4 cylinders. Engine power was 80 kW. The cycle time length of the test was 96 hours alternating slow engine speed with a speed of 4 000 rpm. The temperature of the lubricating composition was 145° C. and the temperature of the water in the coolant system was 100° C. No oil change and no topping up with lubricating composition were carried out during the test. The fuel used was EN 590.

[0125] The test was conducted in two phases for a total time of 106 hours, with a first rinsing and run-in step for 10 hours and second step with the evaluated composition (4 kg), and finally an endurance step lasting 96 hours with the evaluated composition (4 kg).

[0126] Throughout the test, the physicochemical parameters of the lubricant were evaluated. Lubricant consumption during run-in and during the test were evaluated. Deposits on the engine pistons were also evaluated. The results obtained are given in Table 1:

TABLE-US-00002 TABLE 1 Piston cleanliness merit rating after test Evaluated Piston cleanliness merit composition rating after test (%) CL-1 79.6 CC-1 70.4 CL-2 68.1 CC-2 65 CR-1 63

[0127] It can be seen that the lubricating compositions of the invention (CL-1 and CL-2) allow a signification gain in engine cleanliness compared with the comparative lubricating compositions (CC-1 and CC-2). With the lubricating compositions of the invention, the piston cleanliness merit rating after the test is much higher than the rating of the reference lubricating composition (CR-1).

[0128] It was also found that the lubricating compositions of the invention are stable.