Lubricating composition exhibiting improved emulsion stability

Abstract

Lubricating composition exhibiting improved emulsion stability. Lubricating composition comprising: - at least one base oil, - from 0.1% to 13% by mass of at least one additive for improving viscosity index, - at least one organomolybdenum compound, the molybdenum content being at least 400 ppm by mass, - at least one first detergent additive selected from magnesium salts of carboxylic acids, sulfonates, salicylates, naphthenates, phenates and any mixture thereof, - optionally, at least one second detergent additive selected from calcium salts of carboxylic acids, sulfonates, salicylates, naphthenates, phenates and any mixture thereof, in which the cumulative content of magnesium and calcium, relative to the total mass of the lubricating composition, is at least 1000 ppm by mass. Figure for the abridged version: None

Description

Title of the invention: Lubricating composition exhibiting improved emulsion stability

[0001] The present invention relates to the lubrication of vehicles comprising at least one internal combustion engine. In particular, the present invention relates to the lubrication of hybrid vehicle engines, specifically plug-in hybrid vehicles and hybrid vehicles including a range extender.

[0002] Hybrid vehicles comprise two engines, an internal combustion engine and an electric motor. In most hybrid vehicles, the internal combustion engine drives the wheels and is assisted by an electric motor. A battery supplies the electricity necessary for the operation of the electric motor; in the case of conventional hybrid vehicles, this battery is recharged during braking and deceleration phases by a kinetic energy recovery (KERA) system integrated into the vehicle.

[0003] There are various hybrid vehicle technologies. Among these hybrid technologies, we can notably mention:

[0004] - micro-hybrid vehicles (also called mild hybrid vehicles), these vehicles, equipped with the "stop&start" system, they recover the energy generated by braking to charge a battery which can momentarily assist the internal combustion engine;

[0005] - mild-hybrid vehicles that include electric assistance during accelerations;

[0006] - Full hybrid vehicles are vehicles whose hybridization is total. At low At speed, when the battery is charged, the electric motor handles starting and propulsion. At high speeds, or when the battery is depleted, the internal combustion engine takes over. When increased power is needed (for example, during acceleration), both engines work together. It is therefore possible to drive with the internal combustion engine off for a few kilometers.

[0007] Other complementary technologies have recently been developed: plug-in hybrid vehicles and hybrid vehicles with a range extender. Plug-in hybrid vehicles include a combustion engine and an electric motor; the battery can be recharged from the electrical grid, allowing these vehicles to travel in 100% electric mode for a distance of several tens of kilometers, for example, 50 kilometers. In hybrid vehicles with a range extender, only the electric motor drives the wheels. This electric motor is powered by a battery for several tens of kilometers. kilometers. When the battery reaches a certain charge threshold (for example, around 30%), the internal combustion engine starts and drives a current generator to produce the electricity needed to recharge the battery and maintain the operation of the electric motor.

[0008] Lubricating compositions, and in particular those used for the lubrication of internal combustion engines, generally contain small amounts of water resulting from, among other things, the direct adsorption of water from the air by the lubricant or the condensation of ambient water vapor. A lubricating composition thus typically contains 0 to 10% water. Although present in trace amounts, water in lubricating compositions can cause cold-start problems, corrosion, and premature wear of the internal combustion engine. To prevent these phenomena, it is therefore necessary to maintain this water in emulsion form.

[0009] However, in hybrid vehicle engines, particularly plug-in hybrid vehicles or those incorporating a range extender, the internal combustion engine is used less frequently, which notably increases the likelihood of lubricant composition separation problems. As the lubricant composition remains stationary, the emulsion becomes unstable, the water separates from the oil phase, and a continuous phase forms.

[0010] Similar problems are also observed with conventional vehicles equipped solely with an internal combustion engine (non-hybrid vehicles) and operating only occasionally, particularly with gasoline engines. Since the lubricating composition is not regularly circulated within the engine, the water present tends to separate from the rest of the lubricating composition and form a continuous phase.

[0011] It is therefore necessary to provide a specific lubricating composition enabling the lubrication of such motorization systems, while also preventing problems of mismixing.

[0012] An objective of the present invention is to provide a lubricating composition enabling the lubrication of internal combustion engines, in particular engines of plug-in hybrid vehicles or vehicles including a range extender.

[0013] Another objective of the present application is to provide a lubricating composition exhibiting improved emulsion stability. In particular, the objective of the invention is to provide a lubricating composition capable of maintaining the water present in the form of stable emulsions.

[0014] These objectives are met by the present application, which relates to a lubricating composition comprising:

[0015] - at least one base oil,

[0016] - from 0.1% to 13% by mass, relative to the total mass of the lubricating composition, of at least one additive to improve the viscosity index,

[0017] - at least one organomolybdenum compound, the molybdenum content being at less than 400 ppm by mass, relative to the total mass of the lubricating composition,

[0018] - at least a first detergent additive selected from magnesium salts of acids carboxylic acids, sulfonates, salicylates, naphthenates, phenates, and any mixtures thereof,

[0019] - optionally, at least one second detergent additive selected from the salts of calcium, carboxylic acids, sulfonates, salicylates, naphthenates, phenates, and any mixtures thereof,

[0020] in which the cumulative content of magnesium and calcium elements, relative to the total mass of the lubricating composition, is at least 1000 ppm by mass. The base oil

[0021] The base oils used in the lubricating compositions according to the invention can be oils of mineral or synthetic origin, possibly regenerated, belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) (Table A) or their mixtures.

[0022] [Tables 1] Saturates content Sulfur content Viscosity index (VI) Group I Mineral oils <90% > 0.03% 80 <VI<120 Groupement II Huiles hydrocraquées > 90% <0.03% 80 <VI< 120 Groupement III Huiles hydrocraquées ou hydro-isomérisées > 90% <0.03% >120 Group IV Polyalphaolefins (PAO) Group V Esters and other bases not included in groups I to IV

[0023] Mineral base oils according to the invention include all types of bases obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing.

[0024] Mixtures of synthetic and mineral oils, possibly regenerated, may also be used.

[0025] There is generally no limitation on the use of different lubricating bases to produce the lubricating compositions according to the invention, except that they must have properties, in particular of viscosity, viscosity index, sulfur content, resistance to oxidation, suitable for use in engines or vehicle transmissions.

[0026] The base oils of the lubricating compositions according to the invention can also be selected from synthetic oils, such as certain esters of carboxylic acids and alcohols, and from polyalphaolefins. Polyalphaolefins used as base oils are, for example, obtained from monomers comprising 4 to 32 carbon atoms, for example from octene or decene, and whose viscosity at 100 °C is between 1.5 and 15 mm².s⁻¹ according to ASTM D445. Their average molecular weight is generally between 250 and 3,000 according to ASTM D5296.

[0027] The lubricating composition according to the invention may comprise at least 50% by mass of base oils relative to the total mass of the composition. More advantageously, the lubricating composition according to the invention comprises at least 60% by mass, or even at least 70% by mass, of base oils relative to the total mass of the composition. Even more advantageously, the lubricating composition according to the invention comprises from 75% to 95% by mass of base oils relative to the total mass of the composition.

[0028] The additive for improving the viscosity index

[0029] The lubricating composition according to the invention comprises at least one additive for improving the viscosity index of the lubricating composition (in English, "viscosity index improver").

[0030] By "additive to improve viscosity index", for the purposes of the invention means a chemical compound to ensure good cold performance and minimum high-temperature viscosity of the lubricating composition.

[0031] Examples of viscosity index improving polymers include polymer esters; homopolymers or copolymers, hydrogenated or non-hydrogenated, of styrene, butadiene and isoprene; homopolymers or copolymers of olefin, such as ethylene or propylene; polyacrylates and polymethacrylates (PMA).

[0032] The lubricating composition according to the invention typically comprises from 0.1% to 13% by mass of additive(s) improving the viscosity index, relative to the total weight of the lubricating composition.

[0033] Preferably, the lubricating composition according to the invention comprises from 0.5% to 12% by mass of additive(s) improving the viscosity index, relative to the total weight of the lubricating composition, more preferably from 1% to 10% by mass, even more preferably from 5% to 10% by mass. The organomolybdenum compound

[0034] The lubricating composition according to the invention comprises at least one organomolybdenum compound.

[0035] By organomolybdenum compound according to the invention, we mean any fat-soluble organomolybdenum compound.

[0036] The organomolybdenum compound according to the present invention can be selected from organic molybdenum complexes comprising at least one molybdenum chemical element (Mo), preferably at least two molybdenum chemical elements (Mo), and at least one ligand such as a carboxylate ligand, an ester ligand, an amide ligand, a dithiophosphate ligand, a dithiocarbamate ligand.

[0037] For example, organic complexes of molybdenum with carboxylates, esters, amides can be obtained by reaction of molybdenum oxide or ammonium molybdates with fats, glycerides, fatty acids or fatty acid derivatives (esters, amines, amides, ...).

[0038] For the purposes of the invention, carboxylate ligands, ester ligands and amide ligands are free of sulfur and phosphorus.

[0039] In one embodiment, the organomolybdenum compound of the invention is selected from molybdenum complexes with amide ligands, mainly prepared by reaction of a molybdenum source, which may be, for example, molybdenum trioxide, and an amine derivative, and fatty acids comprising, for example, 4 to 36 carbon atoms such as, for example, fatty acids contained in vegetable or animal oils.

[0040] The synthesis of such compounds is described for example in patents US4889647, EP0546357, US5412130 or EP1770153.

[0041] According to a preferred embodiment, the organomolybdenum compound is chosen from among the dinuclear organomolybdenum compounds.

[0042] The term "dinuclear organomolybdenum compound" refers, in the context of this invention, to organomolybdenum compounds whose nucleus contains two molybdenum atoms. These are also referred to as dimeric organomolybdenum compounds.

[0043] In a preferred embodiment of the invention, the organomolybdenum compound is selected from organic molybdenum complexes with amide ligands obtained by reaction:

[0044] (i) of a fatty substance of the mono, di or triglyceride type, or fatty acid,

[0045] (ii) of an amino source of formula (A):

[0046] in which:

[0047] - X1 represents an oxygen atom or a nitrogen atom,

[0048] - X2 represents an oxygen atom or a nitrogen atom,

[0049] - n or m represents 1 when respectively X1 or X2 represents an atom of oxygen,

[0050] n or m represents 2 when respectively X1 or X2 represents a nitrogen atom,

[0051] (iii) and a molybdenum source chosen from molybdenum trioxide or molybdates, preferably ammonium molybdate.

[0052] In one embodiment of the invention, the organomolybdenum compound may comprise from 0.1 to 30% by weight, preferably from 0.1 to 20%, more preferably from 2 to 8.5% by weight of molybdenum relative to the total weight of the organomolybdenum complex.

[0053] Preferably, the organomolybdenum compound comprises at least one organic molybdenum complex of formula (I) or (II), alone or in mixture:

[0054] in which:

[0055] - X1 represents an oxygen atom or a nitrogen atom;

[0056] - X2 represents an oxygen atom or a nitrogen atom;

[0057] - n represents 1 when X1 represents an oxygen atom and m represents 1 when X2 represents an oxygen atom;

[0058] - n represents 2 when X1 represents a nitrogen atom and m represents 2 when X2 represents a nitrogen atom;

[0059] Ri represents a linear or branched alkyl group, saturated or unsaturated, comprising from 4 to 36 carbon atoms, preferably from 4 to 20 carbon atoms, advantageously from 6 to 18 carbon atoms; (H)

[0060] in which:

[0061] - X1 represents an oxygen atom or a nitrogen atom;

[0062] -X2 represents an oxygen atom or a nitrogen atom;

[0063] -n represents 1 when X1 represents an oxygen atom and m represents 1 when X2 represents an oxygen atom;

[0064] - n represents 2 when X1 represents a nitrogen atom and m represents 2 when X2 represents a nitrogen atom;

[0065] - Ri represents a linear or branched alkyl group, saturated or unsaturated, comprising from 4 to 36 carbon atoms, preferably from 4 to 20 carbon atoms, advantageously from 6 to 18 carbon atoms;

[0066] -R2 represents a linear or branched alkyl group, saturated or unsaturated, comprising from 4 to 36 carbon atoms, preferably from 4 to 20 carbon atoms, advantageously from 6 to 18 carbon atoms.

[0067] Advantageously, the organic molybdenum complex of formula (I) or (II) is prepared by reaction: i. ii. iii. of a fatty substance of the mono, di or triglyceride type, or fatty acid, of diethanolamine or 2-(2-aminoethyl) aminoethanol, and a source of molybdenum chosen from molybdenum trioxide or the molybdates, preferably ammonium molybdate.

[0068] More advantageously, the organic molybdenum complex of formula (I) consists of at least one compound of formula (Ia) or (Ib), alone or in mixture:

[0069] wherein Ri represents a linear or branched, saturated or unsaturated alkyl group comprising from 4 to 36 carbon atoms, preferably from 4 to 20 carbon atoms, advantageously from 6 to 18 carbon atoms, H

[0070] wherein Ri represents a linear or branched, saturated or unsaturated alkyl group comprising from 4 to 36 carbon atoms, preferably from 4 to 20 carbon atoms, advantageously from 6 to 18 carbon atoms.

[0071] As an example of sulfur-free molybdenum complexes according to the invention, Molyvan 855® marketed by Vanderbilt may be cited.

[0072] In another embodiment of the invention, the organomolybdenum compound is selected from organic molybdenum complexes with dithiophosphate ligands or organic molybdenum complexes with dithiocarbamate ligands.

[0073] For the purposes of the invention, organic molybdenum complexes with dithiophosphate ligands are also called molybdenum dithiophosphates or Mo-DTP compounds and organic molybdenum complexes with dithiocarbamate ligands are also called molybdenum dithiocarbamates or Mo-DTC compounds.

[0074] In a more preferred embodiment of the invention, the organomolybdenum compound is selected from among molybdenum dithiocarbamates.

[0075] Mo-DTC compounds are complexes formed of a molybdenum metal core bonded to one or more ligands, the ligand being an alkyl dithiocarbamate group. These compounds are well known to those skilled in the art.

[0076] In one embodiment of the invention, the Mo-DTC compound may comprise from 1 to 40%, preferably from 2 to 30%, more preferably from 3 to 28%, advantageously from 4 to 15% by weight of molybdenum, relative to the total weight of the Mo-DTC compound.

[0077] In another embodiment of the invention, the Mo-DTC compound may comprise from 1 to 40%, preferably from 2 to 30%, more preferably from 3 to 28%, advantageously from 4 to 15% by weight of sulfur, relative to the total weight of the Mo-DTC compound.

[0078] In a preferred embodiment of the invention, the Mo-DTC compound is a dimeric Mo-DTC compound.

[0079] Examples of dimeric Mo-DTC compounds include compounds and their preparation processes as described in documents EP 0757093, EP 0719851, EP 0743354 or EP 1013749.

[0080] Dimeric Mo-DTC compounds generally correspond to compounds of formula (III):

[0081] in which:

[0082] R3, R4, R5, R6, whether identical or different, independently represent a grouping hydrocarbon selected from the alkyl, alkenyl, aryl, cycloalkyl or cycloalkenyl groups,

[0083] X3, X4, X5 and X6, whether identical or different, independently represent an atom of oxygen or a sulfur atom.

[0084] By alkyl group in the sense of the invention, we mean a hydrocarbon group, linear or branched, saturated or unsaturated, comprising from 1 to 24 carbon atoms, preferably from 4 to 18 carbon atoms.

[0085] In one embodiment of the invention, the alkyl group is selected from the group formed by methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, hexadecyl, stearyl, icosyl, docosyl, tetracosyl, triacontyl, 2-ethylhexyl, 2-butyloctyl, 2-butyldecyl, 2-hexylloctyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldodecyl, 2-Octyldodecyl, 2-Decyltetradecyl, 2-Dodecylhexadecyl, 2-Hexadecyloctadecyl, 2-Tetradecyloctadecyl, myristyle, palmityl and stearyl.

[0086] For the purposes of this invention, an alkenyl group is defined as a linear or branched hydrocarbon group comprising at least one double bond and comprising from 2 to 24 carbon atoms. The alkenyl group may be selected from vinyl, allyl, propenyl, butenyl, isobutenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, and oleic.

[0087] For the purposes of this invention, an aryl group is defined as a polycyclic aromatic hydrocarbon or an aromatic group, whether or not substituted by an alkyl group. The aryl group may comprise from 6 to 24 carbon atoms.

[0088] In one embodiment, the aryl group may be selected from the group formed by phenyl, toluyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, the nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, phenylphenyl, benzylphenyl, phenyl-styrene, p-cumylphenyl and naphthyl.

[0089] For the purposes of this invention, cycloalkyl group means a polycyclic or cyclic hydrocarbon, substituted or not by an alkyl group.

[0090] For the purposes of this invention, cycloalkenyl group means a polycyclic or cyclic hydrocarbon, substituted or not by an alkyl group, and comprising at least one unsaturation.

[0091] Cycloalkyl groups and cycloalkenyl groups can comprise from 3 to 24 carbon atoms.

[0092] For the purposes of the present invention, the cycloalkyl groups and the cycloalkenyl groups may be chosen, without limitation, from the group consisting of cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl.

[0093] In a preferred embodiment of the invention, R3, R4, R5 and R6, identical or different, independently represent an alkyl group comprising from 1 to 24 carbon atoms, preferably from 4 to 18 carbon atoms, or an alkenyl group comprising from 2 to 24 carbon atoms.

[0094] In one embodiment of the invention, X3, X4, X5 and X6 may be identical and may represent a sulfur atom.

[0095] In another embodiment of the invention, X3, X4, X5 and X6 may be identical and may be an oxygen atom.

[0096] In another embodiment of the invention, X3 and X4 may represent a sulfur atom and X5 and X6 may represent an oxygen atom.

[0097] In another embodiment of the invention, X3 and X4 may represent an oxygen atom and X5 and X6 may represent a sulfur atom.

[0098] In another embodiment of the invention, the ratio of the number of sulfur atoms to the number of oxygen atoms (S / O) of the Mo-DTC compound can vary from (1 / 3) to (3 / 1).

[0099] In another embodiment of the invention, the Mo-DTC compound of formula (III) can be chosen from a symmetric Mo-DTC compound, an asymmetric Mo-DTC compound and their combination.

[0100] By symmetrical Mo-DTC compound according to the invention, we mean a Mo-DTC compound of formula (V) in which the R3, R4, R5 and R6 groups are identical.

[0101] By asymmetric Mo-DTC compound according to the invention, we mean a Mo-DTC compound of formula (V) in which the R3 and IL groups are identical, the Groups R5 and R6 are identical and groups R3 and R4 are different from groups R5 and R6.

[0102] In a preferred embodiment of the invention, the Mo-DTC compound is a mixture of at least one symmetrical Mo-DTC compound and at least one asymmetrical Mo-DTC compound.

[0103] In one embodiment of the invention, R3 and R4, identical, represent an alkyl group comprising from 5 to 15 carbon atoms, preferably from 8 to 13 carbon atoms, and R5 and R6, identical, represent an alkyl group comprising from 5 to 15 carbon atoms, preferably from 8 to 13 carbon atoms, and the groups R3 and R4 are identical or different from the groups R5 and R6.

[0104] In another preferred embodiment of the invention, R3 and R4, which are identical, represent an alkyl group comprising 6 to 10 carbon atoms and R5 and R6, which are identical, represent an alkyl group comprising 10 to 15 carbon atoms, and groups R3 and R4 are different from groups R5 and R6.

[0105] In another preferred embodiment of the invention, R3 and R4, which are identical, represent an alkyl group comprising 10 to 15 carbon atoms and R5 and R6, which are identical, represent an alkyl group comprising 6 to 10 carbon atoms, and groups R3 and R4 are different from groups R5 and R6.

[0106] In another preferred embodiment of the invention, R3, R4, R5 and R6, which are identical, represent an alkyl group comprising from 5 to 15 carbon atoms, preferably from 8 to 13 carbon atoms.

[0107] Advantageously, the Mo-DTC compound is selected from compounds of formula (III) in which:

[0108] - X3 and X4 represent an oxygen atom,

[0109] - X5 and X6 represent a sulfur atom,

[0110] - R3 represents an alkyl group comprising 8 carbon atoms or a alkyl group comprising 13 carbon atoms,

[0111] - IC represents an alkyl group comprising 8 carbon atoms or a alkyl group comprising 13 carbon atoms,

[0112] - R5 represents an alkyl group comprising 8 carbon atoms or a alkyl group comprising 13 carbon atoms,

[0113] - R6 represents an alkyl group comprising 8 carbon atoms or a alkyl group comprising 13 carbon atoms.

[0114] Thus, advantageously, the Mo-DTC compound is chosen from among the compounds

[0115] of formula (III- a) (III-a)

[0116] in which the groups R3, R4, R5 and R6 are such as defined for formula (III).

[0117] More advantageously, the Mo-DTC compound is a mixture:

[0118] - of a Mo-DTC compound of formula (III-a) in which R3, R4, R5 and R6 represent an alkyl group comprising 8 carbon atoms,

[0119] - of a Mo-DTC compound of formula (III-a) in which R3, R4, R5 and R6 represent an alkyl group comprising 13 carbon atoms, and / or

[0120] - of a Mo-DTC compound of formula (III-a) in which R3, R4 represent a alkyl group comprising 8 carbon atoms and R5 and R6 represent an alkyl group comprising 13 carbon atoms.

[0121] Examples of Mo-DTC compounds include Molyvan L®, Molyvan 807® or Molyvan 822® products marketed by RT Vanderbilt Company® or Sakura-lube 200®, Sakura-lube 165®, Sakura-lube 525® or Sakura-lube 600® products marketed by Adeka.

[0122] The lubricating composition according to the invention typically comprises at least 400 ppm mass of molybdenum element, relative to the total mass of the lubricating composition.

[0123] Preferably, the lubricating composition according to the invention comprises at most 1,500 ppm by mass of molybdenum element, relative to the total mass of the lubricating composition, more preferably from 500 ppm to 1,200 ppm, even more preferably from 750 ppm to 1,000 ppm.

[0124] The first detergent additive (magnesium-based)

[0125] The lubricating composition according to the invention also includes at least one first detergent additive.

[0126] Detergent additives generally make it possible to reduce the formation of deposits on the surface of metal parts by dissolving secondary oxidation and combustion products.

[0127] The detergent additives that can be used in the lubricating compositions according to the invention are generally known to those skilled in the art. The detergent additives can be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophobic head. The associated cation can be a metallic cation of an alkali or alkaline earth metal.

[0128] The first detergent additive is typically selected from magnesium salts of carboxylic acids, sulfonates, salicylates, naphthenates, phenates and any mixture thereof,

[0129] According to a preferred embodiment, the first detergent additive is chosen from magnesium sulfonates.

[0130] The detergents used will be either non-superbased (or neutral) or superbased. Detergents are referred to as non-superbased or "neutral" when the metal salts contain the metal in an approximately stoichiometric quantity. Detergents are referred to as superbased when the metal is in excess (in a quantity greater than the stoichiometric quantity). The excess metal, which gives the detergent its superbased character, is in the form of oil-insoluble metal salts. Superbased detergents thus take the form of micelles composed of insoluble metal salts kept in suspension in the lubricating composition by the detergents in the form of oil-soluble metal salts. These micelles may contain one or more types of insoluble metal salts, stabilized by one or more types of detergents.Super-based detergents are said to be of mixed type if the micelles comprise several types of detergents, differing from each other in the nature of their hydrophobic chain.

[0131] Advantageously, the first detergent additive(s) represent from 0.5 to 8% by mass, preferably from 2% to 4% by mass, relative to the total mass of the lubricating composition. The second detergent additive (calcium-based)

[0132] According to a preferred embodiment, the composition according to the invention further comprises at least one second detergent additive.

[0133] The second detergent additive is typically chosen from calcium salts.

[0134] Preferably, the second detergent additive is chosen from calcium salts of carboxylic acids, sulfonates, salicylates, naphthenates, phenates and any of their mixtures.

[0135] Advantageously, the second detergent additive is chosen from calcium carboxylates, preferably from calcium salicylates.

[0136] The detergents used will be either non-superbased (or neutral) or superbased. Detergents are considered non-superbased or "neutral" when the metal salts contain the metal in an approximately stoichiometric quantity. Detergents are considered superbased when the metal is in excess (in a quantity greater than the stoichiometric quantity). The excess metal that gives the detergent its superbased character is in the form of oil-insoluble metal salts. Superbased detergents thus take the form of micelles composed of insoluble metal salts kept in suspension in the lubricating composition by the detergents in the form of oil-soluble metal salts. These micelles may contain one or more types of insoluble metallic salts, stabilized by one or more types of detergents. Over-based detergents will be said to be of mixed type if the micelles comprise several types of detergents, different from each other by the nature of their hydrophobic chain

[0137] Advantageously, when present, the second detergent additive represents from 0.5 to 8% by mass, preferably from 2% to 4% by mass, relative to the total mass of the lubricating composition.

[0138] According to one embodiment, the composition according to the invention is free of a second detergent additive.

[0139] Preferably, according to this embodiment, the magnesium content is at least 1000 ppm by mass, relative to the total mass of the lubricating composition, more preferably from 1100 ppm to 3000 ppm, even more preferably from 1400 ppm to 2800 ppm, typically from 1600 ppm to 2650 ppm.

[0140] According to a preferred embodiment, the composition according to the invention comprises at least a first detergent additive and at least a second detergent additive.

[0141] Preferably, according to this preferred embodiment, the cumulative content of magnesium and calcium elements, relative to the total mass of the lubricating composition, is at least 1000 ppm by mass, more preferably from 1100 ppm to 3000 ppm, even more preferably from 1400 ppm to 2800 ppm, typically from 1600 ppm to 2650 ppm.

[0142] For the purposes of this invention, "cumulative content of magnesium and calcium" means the sum of the magnesium content present in the lubricating composition and the calcium content present in the lubricating composition.

[0143] Preferably, the ratio between the content of the element calcium (from the first detergent additive) and the content of the element magnesium (from the second detergent additive) is from 10:1 to 1:10.

[0144] Advantageously, the ratio between the content of the element calcium and the content of the element magnesium goes from 5:1 to 1:5, preferably from 5:2 to 5:2, more preferably from 5:2 to 1:1.

[0145] The BN (Base Number measured according to ASTM D-2896) of the lubricating compositions according to the present invention, is totally or partly provided by neutral or over-based detergents based on alkali or alkaline earth metals, in particular by the first and second detergent additives.

[0146] The BN value of the lubricating compositions according to the present invention, measured according to ASTM D-2896, can vary from 1 to 140 mg KOH / g, preferably from 3 to 80 mg KOH / g, more preferably from 5 to 50 mg KOH / g, typically from 5 to 20 mg KOH / g. The BN value will be chosen according to the conditions of use. lubricating compositions and especially depending on the sulfur content of the fuel used. Other additives

[0147] Numerous optional additives may also be present in the lubricating compositions according to the invention.

[0148] The preferred additives for the lubricating composition according to the invention are chosen from detergent additives different from the first and second detergent additives defined above, friction modifier additives differ from the molybdenum compounds defined above, extreme pressure additives, dispersants, pour point activators, antifoaming agents, thickeners and mixtures thereof.

[0149] Preferably, the lubricating compositions according to the invention comprise at least one extreme pressure additive, or a mixture.

[0150] Anti-wear additives and extreme pressure additives protect surfaces from friction by forming a protective film adsorbed onto their surfaces.

[0151] There is a wide variety of anti-wear additives. Preferably, for the lubricating compositions of the invention, the anti-wear additives are chosen from among additives comprising phosphorus and sulfur, such as alkylthiophosphate metals, in particular zinc alkylthiophosphate, and more specifically zinc dialkyldithiophosphate or ZnDTP. The preferred compounds have the formula Zn((SP(S)(OR)(OR'))2, in which R and R', identical or different, independently represent an alkyl group, preferably an alkyl group comprising from 1 to 18 carbon atoms.

[0152] Amine phosphates are also anti-wear additives that can be used in the lubricating compositions of the invention. However, the phosphorus atoms provided by these additives can act as a poison for the catalytic converters of automobiles since they generate ash. It is possible to minimize these effects by substituting a portion of the amine phosphates with additives that do not provide phosphorus, such as, for example, polysulfides, in particular sulfur-containing olefins.

[0153] Advantageously, the lubricating compositions according to the invention can comprise from 0.01 to 6% by mass, preferably from 0.05 to 4% by mass, more preferably from 0.1 to 2% by mass relative to the total mass of lubricating composition, of anti-wear and extreme pressure additives.

[0154] Advantageously, the lubricating compositions according to the invention comprise from 0.01 to 6% by mass, preferably from 0.05 to 4% by mass, more preferably from 0.1 to 2% by mass relative to the total mass of lubricating composition, of anti-wear additives (or anti-wear compound).

[0155] Advantageously, the compositions according to the invention may comprise at least one friction-modifying additive other than the molybdenum compounds of the invention. The friction-modifying additives may, in particular, be selected from compounds containing metallic elements and ash-free compounds. Among the compounds containing metallic elements, reference may be made to transition metal complexes such as Mo, Sb, Sn, Fe, Cu, and Zn, for which the ligands may be hydrocarbon compounds comprising oxygen, nitrogen, sulfur, or phosphorus atoms. The ash-free friction-modifying additives are generally of organic origin or may be selected from fatty acid and polyol monoesters, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, fatty epoxide borates, fatty amines, or glycerol acid esters.According to the invention, fatty compounds comprising at least one hydrocarbon group comprising from 10 to 24 carbon atoms.

[0156] Advantageously the lubricating composition according to the invention may comprise from 0.01 to 2% by mass or from 0.01 to 5% by mass, preferably from 0.1 to 1.5% by mass or from 0.1 to 2% by mass relative to the total mass of the lubricating composition, of a friction modifying additive other than molybdenum compounds according to the invention.

[0157] Advantageously, the lubricating composition according to the invention may include at least one antioxidant additive.

[0158] Antioxidant additives generally delay the degradation of the lubricating composition. This degradation is most often expressed by the formation of deposits, the presence of sludge, or an increase in the viscosity of the lubricating composition.

[0159] Antioxidant additives generally act as radical scavenging agents or destructive hydroperoxide inhibitors. Commonly used antioxidants include phenolic antioxidants, amine antioxidants, and antioxidants containing sulfur and phosphorus. Some of these antioxidants, for example, those containing sulfur and phosphorus, can generate ash. Phenolic antioxidant additives may be ash-free or in the form of neutral or basic metal salts. Antioxidant additives may include, in particular, sterically hindered phenols, esters of sterically hindered phenols, sterically hindered phenols containing a thioether bridge, diphenylamines, diphenylamines substituted with at least one alkyl group at C12-Cl, N,N'-dialkylaryldiamines, and mixtures thereof.

[0160] Preferably according to the invention, sterically hindered phenols are chosen from compounds comprising a phenol group in which at least one of the carbon atoms in the vicinity of the carbon atom bearing the alcohol function is substituted by at least one alkyl group in Cl to C10, preferably an alkyl group in Cl to C6, preferably an alkyl group in C4, preferably a ter-butyl group.

[0161] Amine compounds are another class of antioxidant additives that can be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example aromatic amines of formula NRaRbRc in which Ra represents an aliphatic or aromatic group, optionally substituted, Rb represents an aromatic group, optionally substituted, Rc represents a hydrogen atom, an alkyl group, an aryl group or a group of formula RdS(O)zRe in which Rd represents an alkylene or alkenylene group, Re represents an alkyl, alkenyl or aryl group and z represents 0, 1 or 2.

[0162] Alkyl-phenols containing sulfur or their alkali or alkaline earth metal salts can also be used as antioxidant additives.

[0163] Other classes of antioxidant additives are compounds comprising copper, for example copper thio- or dithio-phosphate, copper salts of carboxylic acids, dithiocarbamates, sulfonates, phenates, copper acetylacetonates. Copper I and II salts, succinic acid salts, or succinic anhydride salts may also be used.

[0164] Lubricating compositions according to the invention may also include any type of antioxidant known to those skilled in the art.

[0165] Advantageously, the lubricating composition includes at least one ash-free antioxidant additive.

[0166] Also advantageously the lubricating composition according to the invention comprises from 0.1 to 2% by mass relative to the total mass of the composition, of at least one antioxidant additive.

[0167] The lubricating composition according to the invention may also include at least one detergent additive distinct from the first and second detergent additives defined above.

[0168] Detergent additives are preferably selected from alkali or alkaline earth metal salts of carboxylic acid, sulfonates, salicylates, naphthenates, and phenate salts. The alkali and alkaline earth metals are preferably sodium or barium.

[0169] These metal salts generally comprise the metal in stoichiometric quantities or in excess, that is, in a content greater than the stoichiometric content. These are then over-based detergents; the excess metal implying the over-based nature of the detergent additive is generally in the form of an oil-insoluble metal salt, for example carbonate, hydroxide, oxalate, acetate, glutamate, preferably carbonate.

[0170] Advantageously, the lubricating composition according to the invention can comprise from 0.2% to 8% or from 0.5% to 3% by mass of additional detergent additives (distinct from the first and second detergent additives defined above), relative to the total mass of the lubricating composition.

[0171] Also advantageously, the lubricating composition according to the invention may also include a pour point lowering additive.

[0172] By slowing down the formation of paraffin crystals, the pour point lowering additive generally improves the cold behavior of the lubricating composition according to the invention.

[0173] As an example of pour point lowering additives, we can mention alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalene, alkyl polystyrenes.

[0174] Advantageously, the lubricating composition according to the invention may also include a dispersing agent.

[0175] Dispersing agents may be chosen from Mannich bases, succinimides and their derivatives.

[0176] Also advantageously, the lubricating composition according to the invention can comprise from 0.2 to 10% by mass of dispersing agent relative to the total mass of lubricating composition.

[0177] The lubricating composition according to the invention may also include at least one thickening agent.

[0178] The lubricating composition according to the invention may also include an antifoaming agent and a demulsifying agent. The lubricating composition

[0179] Preferably, the lubricating composition comprises, relative to the total mass of the lubricating composition:

[0180] - from 50% to 95% by mass of at least one base oil,

[0181] - from 0.1% to 13% by mass of at least one additive to improve the index of viscosity,

[0182] - at least one organomolybdenum compound, the molybdenum content ranging from 400 ppm to 1500 ppm by mass,

[0183] - at least one first detergent additive selected from magnesium salts of acids carboxylic acids, sulfonates, salicylates, naphthenates, phenates, and any mixtures thereof,

[0184] - optionally, at least one second detergent additive selected from the salts of calcium, carboxylic acids, sulfonates, salicylates, naphthenates, phenates, and any mixtures thereof,

[0185] in which the cumulative content of magnesium and calcium elements, relative to the total mass of the lubricating composition, ranges from 1000 ppm to 3000 ppm by mass.

[0186] Advantageously, the lubricating composition comprises, relative to the total mass of the lubricating composition:

[0187] - from 60% to 95% by mass of at least one base oil,

[0188] - from 0.5% to 12% by mass of at least one additive to improve the index of viscosity,

[0189] - at least one organomolybdenum compound, the molybdenum content ranging from 500 ppm to 1500 ppm by mass,

[0190] - at least one first detergent additive selected from magnesium sulfonates,

[0191] - optionally, at least one second detergent additive selected from salicylates, calcium,

[0192] in which the cumulative content of magnesium and calcium elements, relative to the total mass of the lubricating composition, ranges from 1400 ppm to 2800 ppm by mass.

[0193] More advantageously, the lubricating composition comprises, relative to the total mass of the lubricating composition:

[0194] - from 75% to 95% by mass of at least one base oil,

[0195] - 5% to 10% by mass of at least one additive to improve the index of viscosity,

[0196] - at least one organomolybdenum compound, the molybdenum content ranging from 750 ppm to 100 ppm by mass,

[0197] - at least one first detergent additive selected from magnesium sulfonates,

[0198] - optionally, at least one second detergent additive selected from salicylates, calcium,

[0199] in which the cumulative content of magnesium and calcium elements, relative to the total mass of the lubricating composition, ranges from 1600 ppm to 2650 ppm by mass. Uses and processes

[0200] The invention also relates to the use of a lubricating composition as defined above for the lubrication of an internal combustion engine.

[0201] Preferably, the engine is chosen from petrol engines and diesel engines, preferably the combustion engine is a petrol engine.

[0202] According to a preferred embodiment, the engine is a plug-in hybrid vehicle engine or a hybrid vehicle engine including a range extender.

[0203] In the context of the present invention, a plug-in hybrid vehicle (also called a rechargeable hybrid vehicle) is defined as a vehicle comprising a combustion engine and an electric motor, the battery being able to be recharged on the electrical grid, this vehicle can thus travel in 100% electric mode for a distance of several tens of kilometers, such as for example for 50 kilometers.

[0204] For the purposes of this invention, a hybrid vehicle including a range extender is defined as a hybrid vehicle in which only the electric motor drives the wheels. This electric motor is powered by a battery for a range of several tens of kilometers. When the battery reaches a certain charge level (for example, around 30%), the internal combustion engine starts and drives a generator to produce the electricity needed to recharge the battery and maintain the operation of the electric motor.

[0205] According to a first embodiment, the invention relates to the use of the lubricating composition according to the invention to prevent and / or stop and / or slow down cold start problems of the engine.

[0206] According to a second embodiment, the invention relates to the use of the lubricating composition according to the invention to prevent and / or inhibit and / or slow down corrosion phenomena that may occur in the engine.

[0207] According to a third embodiment, the invention relates to the use of the lubricating composition according to the invention to prevent and / or inhibit and / or slow down the wear of said engine.

[0208] According to a fourth embodiment, the invention relates to the use of the lubricating composition according to the invention to prevent and / or inhibit and / or slow down the phenomena of demixing of the lubricating composition.

[0209] By "demixing", in the sense of the invention, we mean the phenomenon during which the water present in the lubricating composition, initially in the form of emulsions, spontaneously separates from the mixture to form a continuous aqueous phase.

[0210] The ability of a lubricating composition to prevent demixing phenomena can, for example, be evaluated according to the following protocol:

[0211] 1) prepare a mixture of 100 mL comprising 60 mL of the lubricating composition To test, use 20mL of water and 20mL of fuel, for example E10 type petrol fuel.

[0212] 2) Shake the mixture to make it homogeneous,

[0213] 3) place the mixture in an oven at 60°C for 18h in a closed truncated conical flask.

[0214] After 18 hours of storage, the ability of the lubricant composition to prevent demixing phenomena is visually assessed by an operator.

[0215] If the mixture is in the form of a single phase, this means that the emulsion is stable. The notation "PASSE" is then assigned to the composition lubricating, demonstrating that the lubricating composition is not very sensitive to demixing phenomena.

[0216] Conversely, if the mixture is not homogeneous, particularly due to the formation of an oily supernatant, the lubricant composition is then marked "FAILED". The emulsion is not sufficiently stable, and the lubricant composition does not adequately prevent demixing.

[0217] The invention also relates to a method of lubricating an internal combustion engine, in particular an engine of a plug-in hybrid vehicle or of a hybrid vehicle including a range extender, this method comprising bringing at least one part of the engine into contact with the lubricating composition according to the invention.

[0218] The variants and embodiments detailed below for the additive for improving the viscosity index, the orgnomolybdenum compound, the first detergent additive and the second detergent additive also apply to the various uses defined above.

[0219] The particular, advantageous or preferred characteristics of the combined use according to the invention define particular, advantageous or preferred combinations usable according to the invention.

[0220] The various aspects of the invention can be illustrated by the following examples. Example:

[0221] Example 1: Preparation of lubricating compositions

[0222] The lubricating compositions are prepared by mixing the compounds described in Table 2, at a temperature of approximately 60°C. The percentages indicated correspond to percentages by mass relative to the total mass of the composition.

[0223] [Tables2] Cl C2 C3 * C4 * Base oils (% by weight) 82.5 81.5 83.8 83 Viscosity index improver additive (% by weight) 6.5 6.5 6.5 6.5 Additive package (% by weight) 10 9.5 9.5 9.5 Of which calcium-based detergent (% by weight) 7.5 7.5 7.5 7.5 Of which calcium content (ppm by weight) 1290 1290 1290 1290 Magnesium-based detergent (% by weight) 0.5** 1.5 0.55 - Of which magnesium content (ppm by weight) 480 1290 480 - Organomolydene compound (% by weight) 0.8 0.8 - 0.8 Of which molybdenum content (ppm by weight) weight) 800 800 - 800 PPD* (% by weight) 0.2 0.2 0.2 0.2

[0224] * additive for lowering the pour point ("PourPoint Depressant" in English)

[0225] **The magnesium-based detergent additive is part of the additive package

[0226] The additive for improving the viscosity index is chosen from the poly(methacrylate).

[0227] The additive package includes, in particular, a calcium-based detergent additive, and optionally a magnesium-based detergent additive.

[0228] The additive package used in Example Cl includes both the calcium-based detergent additive and the magnesium-based detergent additive.

[0229] The additive package used in examples C2, C3* and C4* includes only the calcium-based detergent additive. The magnesium-based detergent additive is added separately.

[0230] The organomolybdenum compound is Sakuralube 525®, commercially available from the company Adeka.

[0231] Compositions Cl and C2 are according to the invention.

[0232] Composition C3* is comparative in that it does not comprise organomolybdenum compound.

[0233] Composition C4* is comparative in that it does not include a magnesium-based detergent additive.

[0234] Example 2: Ability to prevent demixing phenomena

[0235] The ability of the above-prepared lubricating compositions to prevent demixing phenomena was evaluated according to the following protocol:

[0236] A 100 mL composition is prepared by mixing 60 mL of the lubricant composition to be tested, 20 mL of water, and 20 mL of E10 type gasoline. The composition is then mixed in an ultrasonic mixer (10,000 rpm) for 1 minute. The composition is poured into a closed truncated conical flask and then placed in an oven at 60°C for 18 hours.

[0237] After 18 hours of storage, the vials are retrieved and the ability of the lubricant composition to prevent demixing phenomena is visually assessed by an operator.

[0238] If the mixture is in the form of a single phase, this means that the emulsion is stable. The notation "PASSE" is then assigned to the lubricating composition, indicating that the lubricating composition is not very sensitive to demixing phenomena.

[0239] Conversely, if the mixture is not homogeneous, particularly due to the formation of an oily supernatant, the lubricant composition is then marked "FAILURE". The emulsion is not sufficiently stable, and the aqueous phase separates from the oil phase. The lubricant composition does not adequately prevent demixing.

[0240] The results obtained are presented in Table 3.

[0241] [Tables3 Cl C2 C3* C4* Results PASS PASS FAILURE FAILURE

[0242] The Cl and C2 compositions according to the invention make it possible to prevent the phenomena of demixing.

[0243] Conversely, the emulsions obtained from the C3* and C4* lubricating compositions are not stable. These lubricating compositions therefore do not prevent demixing phenomena.

Claims

Demands

1. Lubricating composition comprising: - at least one base oil, - 5% to 10% by mass, relative to the total mass of the lubricating composition, of at least one viscosity index improver, - at least one organomolybdenum compound, the molybdenum content being at least 400 ppm by mass, relative to the total mass of the lubricating composition, - at least one first detergent additive selected from magnesium sulfonates, - at least one pour point lowering additive, - optionally, at least one second detergent additive selected from calcium salts of carboxylic acids, sulfonates, salicylates, naphthenates, phenates and any mixture thereof, wherein the cumulative content of magnesium and calcium, relative to the total mass of the lubricating composition, is at least 1000 ppm by mass.

2. Lubricating composition according to claim 1, wherein the molybdenum content is less than or equal to 1500 ppm by mass, relative to the total mass of the lubricating composition.

3. Lubricating composition according to any one of claims 1 or 2, comprising at least one second detergent additive selected from calcium salts of carboxylic acids, sulfonates, salicylates, naphthenates, phenates and any mixture thereof, and wherein the ratio of the elemental calcium content to the elemental magnesium content ranges from 10:1 to 1:

10.

4. Lubricating composition according to claim 3, wherein the ratio between the content of element calcium and the content of element magnesium ranges from 5:1 to 1:5, preferably from 5:2 to 5:2, more preferably from 5:2 to 1:

1.

5. Lubricating composition according to any one of the preceding claims, wherein the second detergent additive is selected from calcium carboxylates, preferably from calcium salicylates.

6. Lubricating composition according to any one of the preceding claims, wherein the organomolybdenum compound is selected from molybdenum dithiocarbamates

7. Use of a lubricating composition according to any one of the preceding claims, for the lubrication of an internal combustion engine.

8. Use according to claim 7, for the lubrication of an internal combustion engine of a plug-in hybrid vehicle or of a hybrid vehicle engine including a range extender.

9. Use according to claim 7 or according to claim 8, to: - prevent and / or prevent and / or slow down cold start problems of said engine, and / or - prevent and / or prevent and / or slow down corrosion phenomena likely to occur in said engine, and / or - prevent and / or prevent and / or slow down wear of said engine, and / or - prevent and / or prevent and / or slow down demixing phenomena of the lubricating composition.

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