LUBRICATING COMPOSITION COMPRISING A PHASE-CHANGE MATERIAL

Abstract

Disclosed is a lubricating composition including a base oil, a surfactant system and a phase-change material, especially water. The lubricating composition according to the invention is used to lubricate engines, especially for a vehicle. It has improved thermal performances compared to lubricating compositions of prior art. It also reduces clogging of the engine parts.

Claims

1-13. (canceled)

14. A monophasic lubricating composition suitable for engine lubrication comprising: a base oil, a surfactant system comprising: at least one non-ionic surfactant derivative of fatty alcohols, or a mixture of at least two non-ionic surfactant derivatives of fatty alcohols, or a condensate of at least two non-ionic surfactant derivatives of fatty alcohols, or any combination thereof; up to 5 weight % of a phase-change material.

15. The monophasic lubricating composition according to claim 14, wherein the surfactant system comprises at least one derivative of polyalkoxylated fatty alcohols comprising a saturated or unsaturated, straight-chain or branched C.sub.12-C.sub.60-alkyl group.

16. The monophasic lubricating composition according to claim 14, wherein the surfactant system comprises at least one derivative selected from among: derivatives of polyalkoxylated fatty alcohols; a fatty alcohol alkoxylate; a fatty alcohol polyglycol ether; a C.sub.16-C.sub.13 oleic alcohol derivative; a C.sub.16-C.sub.13 oleic alcohol derivative comprising saturated C.sub.16-C.sub.13 groups, unsaturated C.sub.13 groups and alkoxy groups; a C.sub.16-C.sub.18 oleic alcohol derivative comprising saturated C.sub.16-C.sub.18 groups, unsaturated C.sub.18 groups and 2 to 5 alkoxy groups.

17. The monophasic lubricating composition according to claim 14, wherein the surfactant system comprises a mixture of: (a) a fatty alcohol alkoxylate; and (b) a C.sub.16-C.sub.18 oleic alcohol derivative comprising saturated C.sub.16-C.sub.18 groups, unsaturated C.sub.18 groups and 2 to 5 alkoxy groups.

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

19. 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.

20. 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.

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

22. The monophasic lubricating composition according to claim 21 wherein the phase-change material is water.

23. The monophasic lubricating composition according to claim 14, wherein the composition comprises up to 3 weight % of phase-change material.

24. The monophasic lubricating composition according to claim 14, wherein the composition is prepared following a method selected from among: method (A) comprising: preparing a mixture comprising: a surfactant system comprising at least one non-ionic surfactant derivative of fatty alcohols, or a mixture of at least two non-ionic surfactant derivatives of fatty alcohols, or a condensate of at least two non-ionic surfactant derivatives of fatty alcohols, or any combination thereof, and a phase-change material; adding this mixture to a base oil; method (B) comprising: preparing a solution comprising: a surfactant system comprising at least one non-ionic surfactant derivative of fatty alcohols, or a mixture of at least two non-ionic surfactant derivatives of fatty alcohols, or a condensate of at least two non-ionic surfactant derivatives of fatty alcohols, or any combination thereof, and a phase-change material; adding this solution to a base oil; method (C) comprising: preparing a mixture comprising: a surfactant system comprising at least one non-ionic surfactant derivative of fatty alcohols, or a mixture of at least two non-ionic surfactant derivatives of fatty alcohols, or a condensate of at least two non-ionic surfactant derivatives of fatty alcohols, or any combination thereof; and a base oil; adding this mixture to a phase-change material; method (D) comprising: preparing a solution comprising: a surfactant system comprising at least one non-ionic surfactant derivative of fatty alcohols, or a mixture of at least two non-ionic surfactant derivatives of fatty alcohols, or a condensate of at least two non-ionic surfactant derivatives of fatty alcohols, or any combination thereof, and a base oil; adding this solution to a phase-change material.

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

26. A monophasic lubricating composition suitable for engine lubrication comprising: a base oil, a surfactant system; and up to 5 weight % of a phase-change material; wherein the surfactant system comprises a mixture of at least two non-ionic surfactant derivatives of a fatty alcohol selected from the group consisting of: a derivative of polyalkoxylated fatty alcohols comprising a saturated or unsaturated, straight-chain or branched C.sub.12-C.sub.60-alkyl group; derivatives of polyalkoxylated fatty alcohols; a fatty alcohol alkoxylate; a fatty alcohol polyglycol ether; a C16-C18 oleic alcohol derivative; a C16-C18 oleic alcohol derivative comprising saturated C16-C18 groups, unsaturated C18 groups and alkoxy groups; and a C16-C18 oleic alcohol derivative comprising saturated C16-C18 groups, unsaturated C18 groups and 2 to 5 alkoxy groups.

Description

EXAMPLE 1: PREPARATION OF MONOPHASIC LUBRICATING COMPOSITIONS ACCORDING TO THE INVENTION COMPRISING A BASE OIL (1)

[0134] Three monophasic lubricating compositions of the invention were prepared following the method of the invention. At a first step, a solution was prepared by adding two surfactant compounds to a base oil. At a second step, this solution was mixed in water.

[0135] The surfactant compounds were known products. These were Emulsogen MTP070 (non-ionic emulsifier comprising a fatty alcohol of vegetable origin—produced by Clariant—having a viscosity measured at 25° C. as per standard EN ISO 2555 of 110 mPa.Math.s, a cloud point measured as per standard DIN ISO 3015 of 11-13° C., a pour point measured as per standard DIN ISO 3016 of 6-8° C.), and Genapol O 020 (CAS 68920-66-1, C.sub.16-C.sub.18 saturated and C.sub.18 unsaturated polyethoxylated oleic alcohol with 2-5 ethoxy repeating units—produced by Clariant—having a density measured at 50° C. as per standard DIN 51757 of 0.88 g/cm.sup.3, a dynamic viscosity measured at 50° C. as per standard DIN 53015 of 12 mPa.Math.s, a pour point measured as per standard DIN ISO 3016 of 11.7° C.).

[0136] The base oil (1) was a Group IV PAO oil (product: Yubase 4+—by SK).

[0137] The compositions of the invention were prepared in the proportions (weight %) given in Table 1.

TABLE-US-00002 TABLE 1 Composition Composition Composition (1) (2) (3) Base oil (1) 94.8 93.4 94.1 Genapol O 020 1.0 1.0 1.0 Emulsogen 4.0 3.9 4.0 MTP 70 Distilled water 0.2 1.7 0.9

[0138] The stability of the compositions of the invention was evaluated and allowed the demonstration that they are stable at ambient temperature and do not exhibit visually distinguishable separated phases

EXAMPLE 2: PREPARATION OF MONOPHASIC LUBRICATING COMPOSITIONS OF THE INVENTION COMPRISING A BASE OIL (2) INCLUDING ADDITIVES

[0139] Two monophasic lubricating compositions of the invention were prepared in similar manner to the monophasic lubricating composition in Example 1, replacing the base oil (1) by a base oil (2) including additives.

[0140] The base oil (2) including additives comprised a Group III base oil (78% by weight—Group III refined base oil of KV100=4.3 mm.sup.2.Math.s.sup.−1—Nexbase 3043—produced by Neste), a Group III base oil (3.1 weight %—Group III refined base oil of KV100=5 mm.sup.2.Math.s.sup.−1—Nexbase 3050—produced by Neste), a VI improving polymer (Viscosity Index) of hydrogenated polyisoprene/styrene type (5.3 weight %—SV261—produced by Infineum), a polymer (0.3 weight %—PPD-polymethacrylate—Lubrizol 7748—produced by Lubrizol) and an additive package (13.3 weight %—salicylate dispersants, succinimide dispersants, zinc dithiophosphate anti-wear, alkylated diphenylamine antioxidant and sterically hindered phenols, polysiloxane defoamer—P6660—produced by Infineum).

[0141] The compositions of the invention were prepared in the proportions (weight %) given in Table 2.

TABLE-US-00003 TABLE 2 Composition (4) Composition (5) Base oil (2) 93.4 94.1 with additives Genapol O 020 1.0 1.0 Emulsogen 3.9 4.0 MTP 70 Distilled water 1.7 0.9

[0142] The stability of the compositions of the invention was evaluated and allowed the demonstration that they are stable at ambient temperature and that they do not exhibit visually distinguishable separated phases.

EXAMPLE 3: PREPARATION OF MONOPHASIC LUBRICATING COMPOSITIONS OF THE INVENTION COMPRISING A BASE OIL (3) INCLUDING ADDITIVES

[0143] Three monophasic lubricating compositions of the invention were prepared in similar manner to the monophasic lubricating composition is Example 2, replacing base oil (2) including additives by a base oil (3) including additives.

[0144] The base oil (3) including additives comprised a Group IV base oil 37.5 weight %—polyalphaolefin with KV100=4 mm.sup.2.Math.s.sup.−1), a Group IV base oil (35 weight %—polyalphaolefin with KV100=6 mm.sup.2.Math.s.sup.−1), a Group V base oil (10 weight %—trimethylolpropane ester—Priolube 3970—produced by Croda), an anti-friction agent (1 weight %—Mo dithiocarbamate—Sakuralube 525—produced by Adeka), a polymer (0.3 weight %—PPD-polymethacrylate—Viscoplex 1-258—produced by Evonik) and an additive package (10 weight %—salicylate dispersants, succinimide dispersants, zinc dithiophosphate anti-wear, antioxidant: alkylated diphenylamine and sterically hindered phenols, defoaming agent: polysiloxane—P6660—produced by Infineum).

[0145] The compositions of the invention were prepared in the proportions (weight %) given in Table 3.

TABLE-US-00004 TABLE 3 Composition Composition Composition (6) (7) (8) Base oil (3) 94.1 93.7 93.6 with additives Genapol O 020 1.0 1.0 1.0 Emulsogen 4.0 3.9 3.9 MTP 70 Distilled water 0.9 1.4 1.5

[0146] The stability of the compositions of the invention was evaluated and allowed the demonstration that they are stable at ambient temperature and that they do not exhibit visually distinguishable separated phases.

COMPARATIVE EXAMPLE 1: PREPARATION OF LUBRICATING COMPOSITIONS COMPRISING A BASE OIL 1

[0147] A comparative composition 1 was prepared according to Example 1. This comparative composition did not comprise water.

[0148] It comprised a base oil 1 (95 weight %), Genapol O 020 (1.0 weight %) and Emulsogen MTP 70 (4.0 weight %).

[0149] This comparative composition was stable.

EXAMPLE 4: EVALUATION OF THE THERMAL PERFORMANCE OF THE MONOPHASIC LUBRICATING COMPOSITIONS OF THE INVENTION

[0150] The heat-capacity rate of the monophasic lubricating compositions of the invention was measured by Differential Scanning Calorimetry—DSC) at different temperatures as per standard ASTM E1269. The latent heat of vaporization of the monophasic lubricating compositions of the invention was also evaluated by DSC under the following conditions: [0151] weight of sample taken: 20 mg, [0152] temperature ramp: 10° C. to 100° C. at 1° C./min, [0153] atmosphere: nitrogen (20 mL/min).

[0154] The results are given in Table 4.

TABLE-US-00005 TABLE 4 Composition Composition Composition Composition Composition (2) (3) (4) (5) (6) heat-capacity rate(J/g .Math. K) at 20° C. 1.66 1.78 1.59 2.09 2.08 at 25° C. 1.75 1.79 1.69 2.11 2.12 at 30° C. 1.83 1.80 1.77 2.12 2.14 at 35° C. 1.88 1.82 1.84 2.14 2.15 at 40° C. 1.93 1.84 1.89 2.16 2.17 at 45° C. 1.97 1.87 1.94 2.18 2.20 at 50° C. 2.00 1.90 1.98 2.22 2.23 at 55° C. 2.03 1.93 2.03 2.25 2.26 at 60° C. 2.05 1.96 2.08 2.28 2.30 Latent heat −4.838 −6.651 −5.085 −9.82 −10.51 of vaporization (J/g)

[0155] The heat-capacity rate of the monophasic lubricating compositions of the invention is particularly advantageous. It increases as a function of temperature.

[0156] The latent heat of vaporization demonstrates the capability of the monophasic lubricating compositions of the invention to evacuate thermal energy when used to lubricate a motor vehicle engine.