Lubricant composition for a motor vehicle transmission

Abstract

The present invention relates to a lubricant composition comprising: - at least one base oil, - at least one additive corresponding to formula (I) in which R and R1 are chosen independently of one another from a hydrogen atom or linear or branched, saturated or unsaturated hydrocarbon groups comprising from 8 to 40 carbon atoms, at least one radical from R and R1 being a hydrocarbon group comprising at least two ethoxylated and / or propoxylated units.

Description

[0001] Description

[0002] Title: Lubricating composition for automobile transmission.

[0003] Technical field

[0004] The present invention relates to the field of lubricating compositions, in particular for motor vehicles, in particular for lubricating the transmission components of motor vehicles, in particular the gears of thermal or electric engine transmissions.

[0005] State of the art

[0006] Transmission components in motor vehicles operate under heavy loads and at high speeds. Oils (also known as lubricating compounds or lubricants) for these transmissions must therefore be particularly effective in protecting parts against wear and fatigue, and in particular in protecting gear teeth against seizure.

[0007] Seizure occurs under high load conditions and can be assessed by monitoring visual deterioration.

[0008] Prevention of this phenomenon involves reducing contact stresses through appropriate part geometry, and reducing friction by preventing adhesion. The lubricating composition plays a role in this prevention process, mainly through the physicochemical reactivity of its additives.

[0009] Anti-wear and extreme pressure additives containing sulfur, phosphorus, or borates are generally added to transmission oils to provide anti-seize properties. Other additives present in the lubricant composition can also have a positive or negative impact on this phenomenon.

[0010] Another advantage that the subject of the invention will have to meet is to avoid the introduction of any additive, and more particularly any extreme pressure anti-wear additive, comprising sulfur. It is desirable to limit, or even completely eliminate sulfur from transmission oils, in particular for transmissions for electric vehicles in order to limit the occurrence of the corrosion phenomenon and to limit the conductivity values ​​to the required levels.

[0011] Advantageously, the composition, object of the present invention, will also not comprise a zinc-based anti-wear additive. Document EP3546550A1 discloses a composition comprising the reaction product between an acid phosphate and a nitrogen compound.

[0012] Document EP3812445A1 discloses a composition comprising an acid phosphate comprising hydrocarbon groups of 1 to 6 carbon atoms.

[0013] The compounds described in these documents do not always have satisfactory lubricating properties, particularly in terms of durability and load capacity.

[0014] It is therefore an object of the present invention to provide a composition for lubricating manual or automatic transmission components, in particular the transmission gears of thermal vehicles or preferably for electric vehicles, said composition having good durability and being free of any sulfur-based additive.

[0015] Summary of the invention

[0016] More specifically, the present invention relates to a lubricating composition comprising:

[0017] - at least one base oil,

[0018] - at least one additive corresponding to formula (I):

[0019] [Chem 1]

[0020] O

[0021] RC P OH! * C'R in which,

[0022] R and R 1 are chosen independently of one another from a hydrogen atom or hydrocarbon groups, linear or branched, saturated or unsaturated, comprising from 8 to 40 carbon atoms, at least one radical from R and R 1 being a hydrocarbon group comprising at least two ethoxylated and / or propoxylated units.

[0023] Preferably, R and R 1 are chosen independently of one another from a hydrogen atom or linear or branched alkyl or alkenyl groups, at least one radical from R and R 1 being an alkyl or alkenyl group further comprising at least two ethoxylated units, preferably among the linear or branched alkyl or alkenyl groups, at least one radical among R and R 1 being an alkyl or alkenyl group further comprising at least two ethoxylated units.

[0024] Preferably, R and / or R 1are chosen independently of one another from a hydrogen atom or hydrocarbon groups consisting of:

[0025] - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0026] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, it being understood that at least one radical among R or R 1 is a hydrocarbon group consisting of:

[0027] - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0028] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, preferably both radicals R and R 1 are chosen independently of one another from the hydrocarbon groups consisting of:

[0029] - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0030] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units.

[0031] According to one embodiment, the lubricating composition comprises:

[0032] - from 250 to 1300 ppm by weight of phosphorus, including preferably from 400 to 1400 ppm by weight of phosphorus provided by the additive(s) corresponding to formula (I) and / or

[0033] - less than 10 ppm by weight of sulfur, preferably less than 5 ppm by weight of sulfur, more preferably less than 1 ppm by weight of sulfur.

[0034] According to a preferred embodiment, the lubricating composition further comprises at least one additive chosen from phosphites comprising from 1 to 24 carbon atoms, preferably from phosphites comprising from 4 to 12 carbon atoms, preferably from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms. According to one embodiment, the lubricating composition comprises from 0.01 to 10% by weight, preferably from 0.05 to 5% by weight, more preferably from 0.1 to 3% by weight, of additive(s) corresponding to formula (I) relative to the total weight of the lubricating composition.

[0035] According to one embodiment, the lubricating composition comprises, relative to the total weight of the lubricating composition:

[0036] - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of additive(s) corresponding to formula (I), and

[0037] - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of additive(s) chosen from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms.

[0038] According to a preferred embodiment of the invention, the lubricating composition further comprises at least one dispersant, preferably a borated dispersant, more preferably a borated dispersant chosen from borated succinimides, more preferably from borated polyisobutene succinimides.

[0039] According to a preferred embodiment, the lubricating composition according to the invention comprises:

[0040] - at least 70% by weight, preferably from 75 to 99.5% by weight of non-aqueous base oil(s);

[0041] - from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of additive(s) corresponding to formula (I);

[0042] - from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of additive(s) chosen from phosphites containing from 1 to 24 carbon atoms;

[0043] - optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, relative to the total weight of the lubricating composition. Preferably, the base oil(s) have a kinematic viscosity at 100°C ranging from 1.5 to 35 cSt.

[0044] The invention also relates to the use of the composition according to the invention for lubricating at least one mechanical part of a motor vehicle, preferably present in a transmission member of a motor vehicle, preferably a gear of a motor vehicle.

[0045] The invention also relates to the use of an additive in a lubricating composition comprising at least one base oil, to improve the load capacity of the lubricating composition, said additive corresponding to formula (I):

[0046] [Chem 1] in which,

[0047] - R and R 1 are chosen independently of one another from a hydrogen atom or linear or branched, saturated or unsaturated hydrocarbon groups, comprising from 8 to 40 carbon atoms, at least one radical from R and R 1 being a hydrocarbon group comprising at least two ethoxylated and / or propoxylated units.

[0048] According to one embodiment, the additive corresponding to formula (I) is used in combination with an additive chosen from phosphites comprising from 1 to 24 carbon atoms, preferably with the following proportions in the lubricating composition:

[0049] - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of additive(s) corresponding to formula (I),

[0050] - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of additive(s) chosen from phosphites containing from 1 to 24 carbon atoms, relative to the total weight of the lubricating composition.

[0051] According to one embodiment, the lubricating composition implemented in the use of the additive is as defined in the invention. In particular, the lubricating composition implemented in the use of the additive according to the invention advantageously has one or more of the following characteristics:

[0052] - R and R 1 are chosen independently of one another from a hydrogen atom or linear or branched alkyl or alkenyl groups, at least one radical from R and R 1being an alkyl or alkenyl group further comprising at least two ethoxylated units, preferably among the linear or branched alkyl or alkenyl groups, at least one radical among R and R 1 being an alkyl or alkenyl group further comprising at least two ethoxylated units, t / or

[0053] - R and / or RI are chosen independently of each other from a hydrogen atom or hydrocarbon groups consisting of: o an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and o from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, it being understood that at least one radical among R or RI is a hydrocarbon group consisting of: o an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and o from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, preferably the two radicals R and RI are chosen independently of each other from hydrocarbon groups consisting of:

[0054] - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0055] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, and / or

[0056] - the lubricating composition comprises: o from 250 to 1300 ppm by weight of phosphorus, including preferably from 400 to 1400 ppm by weight of phosphorus provided by the additive(s) corresponding to formula (I) and / or o less than 10 ppm by weight of sulfur, preferably less than 5 ppm by weight of sulfur, more preferably less than 1 ppm by weight of sulfur, and / or

[0057] - the lubricating composition further comprises at least one additive chosen from phosphites comprising from 1 to 24 carbon atoms, preferably from phosphites comprising from 4 to 12 carbon atoms, preferably from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms, and / or

[0058] - the lubricating composition comprises from 0.01 to 10% by weight, preferably from 0.05 to 5% by weight, more preferably from 0.1 to 3% by weight, of additive(s) corresponding to formula (I) relative to the total weight of the lubricating composition, and / or

[0059] - the lubricating composition comprises, relative to the total weight of the lubricating composition: o from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of additive(s) corresponding to formula (I), and o from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of additive(s) chosen from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms, and / or

[0060] - the lubricating composition further comprises at least one dispersant, preferably a borated dispersant, more preferably a borated dispersant chosen from borated succinimides, more preferably from borated polyisobutene succinimides, and / or

[0061] - the lubricating composition comprises, relative to the total weight of the lubricating composition: o at least 70% by weight, preferably from 75 to 99.5% by weight of non-aqueous base oil(s); o from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of additive(s) corresponding to formula (I); o from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of additive(s) chosen from phosphites containing from 1 to 24 carbon atoms; o optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, and / or

[0062] - the base oil(s) have a kinematic viscosity at 100°C ranging from 1.5 to 35 cSt.

[0063] The lubricating composition according to the invention has the advantage of having very good properties for reducing the phenomenon of seizure.

[0064] The lubricating composition according to the invention also has good durability.

[0065] The lubricating composition exhibits particularly satisfactory performance in reducing wear even under heavy load, even in the absence of a sulfur-based additive and / or in the absence of a zinc-based additive.

[0066] In the rest of the text, the expressions "between ... and . . .", "ranging from . . . to ..." and "varying from ... to ..." are equivalent and are intended to mean that the limits are included, unless otherwise stated.

[0067] Unless otherwise indicated, quantities in a product are expressed by weight, relative to the total weight of the product.

[0068] Detailed description

[0069] The present invention relates to a lubricating composition comprising:

[0070] - at least one base oil,

[0071] - at least one anti-wear additive corresponding to formula (I). Acid phosphate type anti-wear additive of formula (I)

[0072] The lubricating composition according to the invention comprises at least one acid phosphate type additive corresponding to formula (I):

[0073] [Chem 1]

[0074] CR' in which:

[0075] - R and R 1 are chosen independently of one another from a hydrogen atom or hydrocarbon groups, linear or branched, saturated or unsaturated, comprising from 8 to 40 carbon atoms, at least one radical from R and R 1 being a hydrocarbon group comprising at least two ethoxylated and / or propoxylated units.

[0076] For the purposes of the present invention, the term “hydrocarbon groups” means a hydrocarbon chain (comprising carbon and hydrogen atoms) optionally comprising one or more heteroatoms, such as oxygen or nitrogen atoms.

[0077] For the purposes of the present invention, the term “ethoxylated unit” means the bivalent group -OCH2CH2-.

[0078] For the purposes of the present invention, the term “propoxylated unit” means the bivalent group -OCH2CH(CH3)- or -OCH2CH2CH2-.

[0079] Preferably, R and R 1 are chosen independently of one another from linear or branched alkyl or alkenyl groups, further comprising at least two ethoxylated and / or propoxylated units.

[0080] Preferably, R and R 1 are chosen independently of one another from linear or branched alkyl or alkenyl groups, at least one radical from R and R 1being an alkyl or alkenyl group further comprising at least two ethoxylated units.

[0081] Advantageously, R and / or R 1 comprise(s) from 2 to 20 ethoxylated and / or propoxylated units, preferably ethoxylated. According to one embodiment, R and / or R 1 comprises from 2 to 15 ethoxylated and / or propoxylated units, preferably ethoxylated, or even from 3 to 10 ethoxylated and / or propoxylated units, preferably ethoxylated.

[0082] Preferably, the groups R and R 1 independently of one another, in addition to the ethoxylated and / or propoxylated units, comprise a preferably linear alkyl chain, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms.

[0083] Thus, according to one embodiment, the composition according to the invention comprises at least one anti-wear additive corresponding to formula (I) where R and / or R 1are chosen independently of one another from a hydrogen atom or hydrocarbon groups consisting of:

[0084] - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0085] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, it being understood that at least one radical among R or R 1 is a hydrocarbon group consisting of:

[0086] - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0087] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, preferably both radicals R and R 1 are chosen independently of one another from the hydrocarbon groups consisting of:

[0088] - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0089] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units.

[0090] The lubricating composition may optionally comprise a mixture of compounds corresponding to formula (I). Said compounds may vary, for example, by the number of ethoxylated and / or propoxylated units and / or by the number of carbon atoms.

[0091] Preferably, the anti-wear agent(s) corresponding to formula (I) provides from 250 to 1300 ppm by weight of phosphorus. Preferably, the anti-wear additive(s) of formula (I) represents from 0.01 to 10% by weight, preferably from 0.05 to 5% by weight, more preferably from 0.1 to 3% by weight, of the total weight of the lubricating composition according to the invention.

[0092] Phosphite-type anti-wear additive

[0093] According to an advantageous embodiment of the invention, the additive of formula (I) is combined with a phosphite type additive.

[0094] Thus, according to an advantageous embodiment of the invention, the lubricating composition according to the invention further comprises at least one anti-wear additive chosen from phosphites comprising from 1 to 24 carbon atoms, preferably from phosphites comprising from 4 to 12 carbon atoms.

[0095] Advantageously, the phosphite-type anti-wear additive is chosen from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms.

[0096] Particularly advantageously, the phosphite-type anti-wear additive is dibutyl hydrogen phosphite.

[0097] According to one embodiment, the phosphite-type anti-wear additive(s) represents from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of the total weight of the lubricating composition according to the invention.

[0098] According to one embodiment of the invention, the lubricating composition comprises:

[0099] - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of anti-wear additive(s) corresponding to formula (I) where R and R 1 are chosen independently of one another from a hydrogen atom or hydrocarbon groups, linear or branched, saturated or unsaturated, comprising from 8 to 40 carbon atoms, at least one radical from R and R 1 being a hydrocarbon group comprising at least two ethoxylated and / or propoxylated units, and

[0100] - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of anti-wear additive(s) chosen from phosphites containing from 1 to 24 carbon atoms, relative to the total weight of the lubricating composition. According to one embodiment of the invention, the lubricating composition comprises:

[0101] - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of anti-wear additive(s) corresponding to formula (I) where R and R 1 are chosen independently of one another from a hydrogen atom or alkyl or alkenyl groups, linear or branched, at least one radical from R and R 1 being an alkyl or alkenyl group further comprising at least two ethoxylated units, and

[0102] - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of anti-wear additive(s) chosen from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms, relative to the total weight of the lubricating composition.

[0103] According to one embodiment of the invention, the lubricating composition comprises:

[0104] - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of anti-wear additive(s) corresponding to formula (I) where R and R 1 are chosen independently of one another from linear or branched alkyl or alkenyl groups, at least one radical from R and R 1 being an alkyl or alkenyl group further comprising at least two ethoxylated units, and

[0105] - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of anti-wear additive(s) chosen from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms, relative to the total weight of the lubricating composition.

[0106] Base oil(s)

[0107] The lubricating composition according to the invention comprises one or more base oils, preferably in a content of at least 70% by weight, preferably ranging from 75 to 99.5% by weight, more preferably from 80 to 99% by weight, preferentially from 85 to 98% by weight, relative to the total weight of the lubricating composition.

[0108] Preferably, the lubricating composition according to the invention comprises at least one base oil having a kinematic viscosity at 100°C according to the ASTM D445 standard ranging from 1.5 to 35 cSt. Advantageously, the base oils of the lubricating composition according to the invention have a kinematic viscosity at 100°C ranging from 1.5 to 35 cSt.

[0109] These base oils may be selected from base oils conventionally used in the field of lubricating oils, such as mineral, synthetic or natural, animal or vegetable oils or mixtures thereof. Typically, the base oil(s) are non-aqueous base oils.

[0110] It can be a mixture of several base oils, for example a mixture of two, three, or four base oils.

[0111] The base oils of the lubricating compositions considered according to the invention may in particular be oils of mineral or synthetic origin belonging to groups I to V according to the classes defined in the API classification (or their equivalents according to the ATIEL classification) and presented in table 1 below or their mixtures.

[0112] [Table 1]

[0113] Mineral base oils include all types of base oils obtained by atmospheric and vacuum distillation of crude oil, followed by refining operations such as solvent extraction, de-alphatting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing.

[0114] Mixtures of synthetic and mineral oils, which may be bio-sourced, may also be used. There is generally no limitation on the use of different base oils to produce the compositions used according to the invention, except that they must have properties, in particular in terms of viscosity, viscosity index, or resistance to oxidation, suitable for use in propulsion systems of an electric or hybrid vehicle.

[0115] The base oils of the compositions used according to the invention can also be chosen from synthetic oils, such as certain esters of carboxylic acids and alcohols, polyalphaolefins (PAO), and polyalkylene glycols (PAG) obtained by polymerization or copolymerization of alkylene oxides comprising from 2 to 8 carbon atoms, in particular from 2 to 4 carbon atoms.

[0116] PAOs used as base oils are, for example, obtained from monomers comprising 4 to 32 carbon atoms, for example from octene or decene. The weight-average molecular mass of the PAO can vary quite widely. Preferably, the weight-average molecular mass of the PAO is less than 600 Da. The weight-average molecular mass of the PAO can also range from 100 to 600 Da, from 150 to 600 Da, or from 200 to 600 Da.

[0117] Advantageously, the base oil or oils of the lubricating composition according to the invention may be chosen from base oils of group II or III.

[0118] According to an alternative embodiment, the base oil or oils of the composition used according to the invention are chosen from polyalphaolefins (PAO), polyalkylene glycol (PAG) and esters of carboxylic acids and alcohols.

[0119] Additional additives

[0120] The lubricating composition according to the invention may also further comprise all types of functional additives, distinct from the anti-wear of formula (I) and distinct from the phosphite type anti-wear defined in the present invention, suitable for use in a lubricant for motor vehicles, in particular for manual or automatic transmission of motor vehicles.

[0121] Such additives, known to those skilled in the art in the field of motor vehicle lubrication, may be chosen from detergents, dispersants, antioxidants, pour point depressants, antifoam agents, viscosity index improvers, and mixtures thereof. Advantageously, the composition according to the invention comprises at least one functional additive chosen from detergents, dispersants, antioxidants, pour point depressants, antifoam agents, viscosity index improvers, and mixtures thereof.

[0122] Typically, when present, these additional functional additives represent (in total) from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of the total weight of the lubricating composition.

[0123] These additives can be introduced in isolation and / or in the form of a mixture similar to those already available for sale for formulations of commercial lubricants for vehicle engines, with performance levels as defined by T ACEA (Association of European Automobile Manufacturers) and / or TAPI (American Petroleum Institute), well known to those skilled in the art.

[0124] The lubricating composition according to the invention may comprise at least one antioxidant additive.

[0125] The antioxidant additive generally helps to delay the degradation of the composition in service. This degradation can notably result in the formation of deposits, the presence of sludge or an increase in the viscosity of the composition.

[0126] Antioxidant additives act in particular as radical inhibitors or hydroperoxide destroyers. Among the commonly used antioxidant additives, mention may be made of phenolic antioxidant additives and amine antioxidant additives. Phenolic antioxidant additives may be ash-free or in the form of neutral or basic metal salts. The antioxidant additives may in particular be chosen from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted by at least one C1-C12 alkyl group, N,N'-dialkyl-aryl-diamines and mixtures thereof.

[0127] Preferably according to the invention, the sterically hindered phenols are chosen from compounds comprising a phenol group in which at least one vicinal carbon of the carbon carrying the alcohol function is substituted by at least one C1-C10 alkyl group, preferably a C1-C6 alkyl group, preferably a C4 alkyl group, preferably by the tert-butyl group. Amino compounds are another class of antioxidant additives which can be used, optionally in combination with the phenolic antioxidant additives. Examples of amino compounds are aromatic amines, for example aromatic amines of formula NR 10 R n R 12 in which R 10 represents an aliphatic group or an aromatic group, optionally substituted, R 11 represents an aromatic group, optionally substituted, R 12represents a hydrogen atom, an alkyl group, an aryl group or a group of formula R 13 S(O) Z R 14 in which R 13 represents an alkylene group or an alkenylene group, R 14 represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2.

[0128] Sulfurized alkyl phenols or their alkali and alkaline earth metal salts can also be used as antioxidant additives.

[0129] Another class of antioxidant additives is copper compounds, e.g., copper salts of carboxylic acids, copper phenates, copper acetylacetonates. Copper I and II salts, succinic acid or anhydride salts can also be used.

[0130] The lubricating composition according to the invention may contain all types of antioxidant additives known to those skilled in the art.

[0131] Advantageously, the lubricating composition according to the invention comprises at least one ash-free antioxidant additive.

[0132] The lubricating composition according to the invention may comprise from 0.5 to 2% by weight of at least one antioxidant additive, relative to the total weight of the composition.

[0133] The lubricating composition according to the invention may also comprise at least one detergent additive.

[0134] Detergent additives generally reduce the formation of deposits on the surface of metal parts by dissolving secondary oxidation and combustion products.

[0135] The detergent additives that can be used in the lubricating composition according to the invention are generally known to those skilled in the art. The detergent additives may be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophilic head. The associated cation may be a metal cation of an alkali or alkaline earth metal.

[0136] The detergent additives are preferably chosen from alkali metal or alkaline earth metal salts of carboxylic acids, salicylates, naphthenates, as well as phenate salts. The alkali and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

[0137] These metal salts generally contain the metal in a stoichiometric quantity or in excess, i.e. in a quantity greater than the narrow stoichiometric quantity. These are then overbased detergent additives; the excess metal providing the overbased character to the detergent additive is then generally in the form of an oil-insoluble metal salt, for example a carbonate, a hydroxide, an oxalate, an acetate, a glutamate, preferably a carbonate.

[0138] The lubricating composition suitable for the invention may, for example, comprise from 0.5 to 4% by weight of detergent additive, relative to the total weight of the composition.

[0139] Also, the lubricating composition according to the invention may comprise at least one dispersing agent. Typically, the dispersant will ensure the maintenance in suspension and the evacuation of insoluble solid contaminants constituted by the secondary oxidation products which form when the lubricating composition is in service.

[0140] The dispersing agent may be chosen from Mannich bases, succinimide-type compounds, such as polyisobutylene succinimide (PIBSI), optionally borated, or borated dispersants other than succinimides, preferably from borated dispersants, more preferably from borated succinimide dispersants, in particular borated PIB SI.

[0141] The lubricating composition according to the invention may, for example, comprise from 0.2 to 10% by weight of dispersing agent(s), relative to the total weight of the composition.

[0142] The lubricating composition according to the invention may further comprise at least one antifoaming agent.

[0143] The antifoaming agent may be chosen from silicones. 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 of antifoaming agent, relative to the total weight of the composition.

[0144] The lubricating composition according to the invention may also comprise at least one pour point lowering additive (also known as “PPD” agents for “Pour Point Depressant” in English).

[0145] By slowing the formation of paraffin crystals, pour point depressants generally improve the cold behavior of the composition. Examples of pour point depressants include polyalkyl methacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes, and alkylated polystyrenes.

[0146] The lubricating composition according to the invention may also comprise at least one viscosity index improving additive (VI improver). Examples of VI improvers include polymethacrylates, polyisobutenes or fatty acid esters. When present, these additives may represent from 1 to 25% by weight of the total weight of the lubricating composition.

[0147] Preferably, the lubricating composition according to the invention does not comprise anti-wear additives comprising zinc.

[0148] In terms of formulating such a lubricating composition, the anti-wear additive(s) according to the invention may be added to a base oil or mixture of oils, then any other additional additives added.

[0149] Alternatively, the anti-wear additive(s) according to the invention may be added to a pre-existing conventional lubricating formulation, comprising in particular one or more base oils, and possibly additional additives.

[0150] Alternatively, the anti-wear additive(s) according to the invention may be combined with one or more additional additives when present, and the "package" of additives thus formed added to a base oil or mixture of oils. Advantageously, the lubricating composition according to the invention has a kinematic viscosity, measured at 40°C according to the ASTM D445 standard, ranging from 5 to 300 mm 2 / s, especially from 10 to 25 mm2 / s.

[0151] Advantageously, the lubricating composition according to the invention has a kinematic viscosity, measured at 100°C according to the ASTM D445 standard, ranging from 1 to 20 mm 2 / s, especially from 2 to 15 mm 2 / s.

[0152] Preferably, the lubricating composition comprises from 400 to 1400 ppm by weight of phosphorus, including advantageously from 250 to 1300 ppm by weight of phosphorus provided by the anti-wear agent(s) corresponding to formula (I).

[0153] Preferably, the lubricating composition is substantially free of sulfur, preferably completely free of sulfur.

[0154] In particular, the lubricating composition according to the invention preferably does not comprise additives comprising sulfur.

[0155] Thus, the lubricating composition according to the invention typically comprises less than 10 ppm by weight of sulfur, or even less than 5 ppm by weight of sulfur, or even less than 1 ppm by weight of sulfur.

[0156] According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of:

[0157] - a base oil or mixture of base oils;

[0158] - an anti-wear additive corresponding to formula (I);

[0159] - possibly an anti-wear additive chosen from phosphites containing from 1 to 24 carbon atoms;

[0160] - optionally one or more additional additives chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof.

[0161] According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of:

[0162] - at least 70% by weight, preferably from 75 to 99.5% by weight of base oil(s);

[0163] - from 0.01% to 10% by weight, in particular from 0.05% to 5% by weight, of anti-wear additive(s) corresponding to formula (I); - optionally from 0.05 to 5% by weight, in particular from 0.1% to 2% by weight, of anti-wear additive(s) chosen from phosphites containing from 1 to 24 carbon atoms;

[0164] - optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, relative to the total weight of the lubricating composition.

[0165] According to a particular embodiment, the lubricating composition according to the invention comprises:

[0166] - at least 70% by weight, preferably from 75 to 99.5% by weight, of base oil(s);

[0167] - from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of additive(s) corresponding to formula (I);

[0168] - from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of additive(s) chosen from phosphites comprising from 1 to 24 carbon atoms, preferably from 4 to 12 carbon atoms, preferably from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms;

[0169] - optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, relative to the total weight of the lubricating composition.

[0170] According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of:

[0171] - at least 70% by weight, preferably from 75 to 99.5% by weight of base oil(s);

[0172] - from 0.01% to 10% by weight, in particular from 0.05% to 5% by weight, of anti-wear additive(s) corresponding to formula (I);

[0173] - optionally from 0.05 to 5% by weight, in particular from 0.1% to 2% by weight, of anti-wear additive(s) chosen from phosphites containing from 1 to 24 carbon atoms;

[0174] - optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, said composition comprising less than 10 ppm by weight of sulfur, relative to the total weight of the lubricating composition.

[0175] According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of:

[0176] - at least 70% by weight, preferably from 75 to 99.5% by weight of base oil(s);

[0177] - from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of anti-wear additive(s) corresponding to formula (I);

[0178] - from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of anti-wear additive(s) chosen from phosphites containing from 1 to 24 carbon atoms;

[0179] - optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, relative to the total weight of the lubricating composition.

[0180] According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of:

[0181] - at least 70% by weight, preferably from 75 to 99.5% by weight of base oil(s);

[0182] - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of anti-wear additive(s) corresponding to formula (I) where R and / or R 1 are chosen independently of one another from the hydrocarbon groups consisting of:

[0183] - an alkyl chain comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0184] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units;

[0185] - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of anti-wear additive(s) chosen from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms;

[0186] - optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, relative to the total weight of the lubricating composition. According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of:

[0187] - at least 70% by weight, preferably from 75 to 99.5% by weight of base oil(s);

[0188] - from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of anti-wear additive(s) corresponding to formula (I);

[0189] - from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of anti-wear additive(s) chosen from phosphites containing from 1 to 24 carbon atoms;

[0190] - from 0.5 to 5% by weight, preferably from 0.1% to 2% by weight, of dispersant(s), preferably chosen from borated dispersants;

[0191] - optionally from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight, of one or more functional additives, preferably chosen from antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, relative to the total weight of the lubricating composition.

[0192] According to a particular embodiment, the lubricating composition according to the invention comprises, or even consists of:

[0193] - at least 70% by weight, preferably from 75 to 99.5% by weight of base oil(s);

[0194] - from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of anti-wear additive(s) corresponding to formula (I) R and / or R 1 are chosen independently of one another from the hydrocarbon groups consisting of:

[0195] - an alkyl chain comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and

[0196] - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units;

[0197] - from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of anti-wear additive(s) chosen from phosphites containing from 1 to 24 carbon atoms;

[0198] - from 0.5 to 5% by weight, preferably from 0.1% to 2% by weight, of dispersant(s), preferably chosen from borated dispersants;

[0199] - optionally from 0.1 to 10% by weight, preferably from 0.5 to 5% by weight, of one or more functional additives, preferably chosen from antioxidants, pour point depressants, anti-foaming agents and mixtures thereof, relative to the total weight of the lubricating composition. The present invention also relates to the use of the lubricating composition according to the invention for lubricating the transmissions of motor vehicles, in particular the gears of the transmissions. The transmissions may be manual or automatic transmissions.

[0200] Preferably, the lubricating composition according to the invention is used to reduce the wear of a mechanical part of a motor vehicle transmission, in particular of a motor vehicle gear. Thus, according to this embodiment, the lubricating composition according to the invention makes it possible to reduce the wear of the transmission gears.

[0201] Preferably, the lubricating composition according to the invention is used to reduce flaking of a mechanical part of a motor vehicle transmission, in particular of a motor vehicle gear.

[0202] According to an advantageous embodiment, the lubricating composition according to the invention is used to both reduce wear and reduce flaking of a mechanical part of a motor vehicle transmission, in particular of a motor vehicle gear.

[0203] The invention also relates, according to another of its aspects, to a method for lubricating at least one part of a transmission of a motor vehicle, in particular a gear of a motor vehicle, comprising at least one step of bringing at least said part into contact with a lubricating composition as described previously.

[0204] The invention also relates, according to another of its aspects, to a method for improving the durability of a lubricating composition, said method comprising a step of mixing at least one anti-wear additive of formula (I) as defined in the present invention, with at least one base oil, preferably said anti-wear additive of formula (I) is further mixed with an anti-wear additive chosen from phosphites comprising from 1 to 24 carbon atoms.

[0205] All of the characteristics and preferences described for the lubricating composition according to the invention as well as for its uses also apply to these methods. According to the invention, the particular, advantageous or preferred characteristics of the composition according to the invention make it possible to define uses according to the invention which are also particular, advantageous or preferred.

[0206] The invention will now be described by means of the following examples, given of course by way of illustration and not limitation of the invention.

[0207] Examples

[0208] Example 1: Preparation of lubricating compositions

[0209] The lubricating compositions were prepared by mixing the ingredients at a temperature of about 40°C, according to methods well known to those skilled in the art. The lubricating compositions that were prepared and tested are detailed in Tables 2 and 3 below.

[0210] The elemental contents of phosphorus and sulfur were calculated based on the elemental contents in the ingredients and are also shown in Tables 2 and 3 in ppm by weight.

[0211] The lubricating compositions tested have a viscosity at 100°C of approximately 4.5 cSt measured according to ASTM D445.

[0212] [Table 2]

[0213] [Table 3]

[0214] In the compositions of tables 2 and 3: - the base oils are group III base oils,

[0215] - anti-wear 12 corresponds to formula (I) where R and R 1 are two linear C18 alkyl chains and where at least one of the radicals R or R 1 further comprises 5 ethoxylated units,

[0216] - anti-wear 13 corresponds to formula (I) where R and R 1 are linear Cl 8 alkyl chains and where at least one of the radicals R or R 1 further comprises 5 ethoxylated units, - anti-wear 14 comprises a mixture of compounds corresponding to formula (I) where R and R 1 are linear C10-C16 alkyl chains and where at least one of the radicals R or R 1 further comprises 5 ethoxylated units,

[0217] - the anti-wear PI is dibutyl hydrogen phosphite,

[0218] - anti-wear Cl does not correspond to formula (I) since it is an acid phosphate with branched C8 alkyl chains, - anti-wear C2 does not correspond to formula (I) since it is an acid phosphate with C5 chains,

[0219] - the dispersant is a borated PIB SI dispersant providing approximately 85 ppm of boron,

[0220] - the antioxidant comprises a phenolic antioxidant and / or an amino antioxidant,

[0221] - the anti-corrosion is a triazole derivative,

[0222] - the additive package contains a pour point improver and an antifoam.

[0223] Example 2: Studies of the performance of lubricating compositions

[0224] The seizing load capacity of the lubricating compositions described in Tables 2 and 3 was tested by the FZG A10 / 16.6R / 90 method (according to the amended CEC-L-84-02 standard). The results are shown in Tables 4 and 5 below.

[0225] The average friction coefficient was determined on an MTM (mini traction machine) machine with the following conditions:

[0226] - load = 5N,

[0227] - rolling speed / drive speed = 3 mm / s,

[0228] - temperature = 90°C,

[0229] - duration = 10 minutes,

[0230] - SSR (slide-roll ratio) = 330%.

[0231] [Table 4]

[0232] [Table 5] The compositions according to the invention CI5 to CI9 have a very good load capacity. These load capacity values ​​(FZG) demonstrate the very good durability of the lubricating composition, particularly for use in transmissions. The compositions according to the invention CI5 to CI9 also have a lower average coefficient of friction, demonstrating better lubricating properties.

[0233] The anti-wear agents corresponding to formula (I) as defined in the present invention make it possible to improve the performance of the lubricating composition. More particularly, the anti-wear agents corresponding to formula (I) as defined in the present invention have better properties than the anti-wear agents C1 and C2 of the state of the art.

Claims

Claims 1. Lubricating composition comprising: - at least one base oil, - at least one additive corresponding to formula (I): [Chem 1] q RC P oi i OR' in which, R and R 1 are chosen independently of one another from a hydrogen atom or hydrocarbon groups, linear or branched, saturated or unsaturated, comprising from 8 to 40 carbon atoms and optionally comprising one or more heteroatoms, at least one radical from R and R 1 being a hydrocarbon group comprising at least two ethoxylated and / or propoxylated units.

2. Lubricating composition according to claim 1, in which R and R 1 are chosen independently of one another from a hydrogen atom or linear or branched alkyl or alkenyl groups, at least one radical from R and R 1being a linear or branched alkyl or alkenyl group, further comprising at least two ethoxylated units, preferably R and R 1 are chosen independently of one another from linear or branched alkyl or alkenyl groups, at least one radical from R and R 1 being an alkyl or alkenyl group further comprising at least two ethoxylated units.

3. A lubricating composition according to any one of the preceding claims, wherein R and / or R 1 are chosen independently of one another from a hydrogen atom or hydrocarbon groups consisting of: - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, it being understood that at least one radical among R or R 1 is a hydrocarbon group consisting of: - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units, preferably both radicals R and R 1 are chosen independently of one another from the hydrocarbon groups consisting of: - an alkyl chain, preferably linear, comprising from 8 to 20 carbon atoms, preferably from 10 to 18 carbon atoms, and - from 2 to 15 ethoxylated units, preferably from 3 to 10 ethoxylated units.

4. Lubricating composition according to any one of the preceding claims, comprising: - from 250 to 1300 ppm by weight of phosphorus, including preferably from 400 to 1400 ppm by weight of phosphorus provided by the additive(s) corresponding to formula (I) and / or - less than 10 ppm by weight of sulfur, preferably less than 5 ppm by weight of sulfur, more preferably less than 1 ppm by weight of sulfur.

5. Lubricating composition according to any one of the preceding claims, further comprising at least one additive chosen from phosphites comprising from 1 to 24 carbon atoms, preferably from phosphites comprising from 4 to 12 carbon atoms, preferably from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms.

6. Lubricating composition according to the preceding claim, comprising from 0.01 to 10% by weight, preferably from 0.05 to 5% by weight, more preferably from 0.1 to 3% by weight, of additive(s) corresponding to formula (I) relative to the total weight of the lubricating composition.

7. Lubricating composition according to one of the preceding claims, comprising, relative to the total weight of the lubricating composition: - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of additive(s) corresponding to formula (I), and - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of additive(s) chosen from phosphites comprising two alkyl groups each having from 2 to 6 carbon atoms.

8. Lubricating composition according to any one of the preceding claims, further comprising at least one dispersant, preferably a borated dispersant, more preferably a borated dispersant chosen from borated succinimides, more preferably from borated polyisobutene succinimides.

9. Lubricating composition according to any one of the preceding claims, comprising: at least 70% by weight, preferably from 75 to 99.5% by weight, of base oil(s); from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of additive(s) corresponding to formula (I); from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of additive(s) chosen from phosphites having from 1 to 24 carbon atoms, preferably from 4 to 12 carbon atoms, preferably from phosphites having two alkyl groups each having from 2 to 6 carbon atoms; relative to the total weight of the lubricating composition.

10. Lubricating composition according to any one of the preceding claims, comprising: at least 70% by weight, preferably from 75 to 99.5% by weight of non-aqueous base oil(s); from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight, of additive(s) corresponding to formula (I); from 0.05 to 5% by weight, preferably from 0.1% to 2% by weight, of additive(s) chosen from phosphites having from 1 to 24 carbon atoms; optionally from 0.1 to 15% by weight, preferably from 1 to 10% by weight, of one or more functional additives, preferably chosen from dispersants, antioxidants, pour point depressants, antifoaming agents and mixtures thereof, relative to the total weight of the lubricating composition.

11. A lubricating composition according to any preceding claim, wherein the base oil(s) have a kinematic viscosity at 100°C ranging from 1.5 to 35 cSt.

12. Use of the composition according to any one of claims 1 to 11, for lubricating at least one mechanical part of a motor vehicle, preferably present in a transmission member of a motor vehicle, preferably a gear of a motor vehicle.

13. Use of an additive in a lubricating composition comprising at least one base oil, to improve the load capacity of the lubricating composition, said additive corresponding to formula (I): [Chem 1] c RC P Oi l CR in which, - R and R 1 are chosen independently of one another from a hydrogen atom or linear or branched, saturated or unsaturated hydrocarbon groups, comprising from 8 to 40 carbon atoms and optionally comprising one or more heteroatoms, at least one radical from R and R 1being a hydrocarbon group comprising at least two ethoxylated and / or propoxylated units.

14. Use according to claim 13, in which the additive corresponding to formula (I) is used in combination with an additive chosen from phosphites comprising from 1 to 24 carbon atoms, preferably with the following proportions in the lubricating composition: - from 0.01 to 5% by weight, preferably from 0.02 to 2% by weight, of additive(s) corresponding to formula (I), - from 0.05 to 5% by weight, preferably from 0.1 to 2% by weight, of additive(s) chosen from phosphites containing from 1 to 24 carbon atoms, relative to the total weight of the lubricating composition.

15. Use according to claim 13 or 14, wherein the lubricating composition is as defined in any one of claims 2 to 11.

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