Lubricant composition for motor vehicle transmission

Abstract

The invention relates to a lubricant composition comprising:-at least one base oil; -at least one additive of formula (I): [Chemical Formula 1] # imgabs0 # wherein R and R1 are each independently selected from the group consisting of: a hydrogen atom; or a saturated or unsaturated linear hydrocarbyl group containing from 8 to 20 carbon atoms; and at least one of the two groups R or R1 is a saturated or unsaturated linear hydrocarbon group containing 8 to 20 carbon atoms.

Description

Technical Field

[0001] The present invention relates to the field of lubricant compositions, particularly for motor vehicles, and more particularly to lubricant compositions for lubricating components of a motor vehicle transmission, in particular gears of a transmission of an internal combustion engine or an electric motor. Background Art

[0002] Motor vehicle transmission components operate under heavy loads and high speeds. Therefore, the oils used for these transmissions (also referred to as "lubricant compositions" or "lubricants") must particularly effectively protect the components against wear, especially the teeth of the gears against the phenomenon of gear seizure (or scuffing / scratching).

[0003] The seizure phenomenon occurs under high load conditions and can be evaluated by monitoring visible deterioration.

[0004] Measures to prevent this phenomenon involve reducing the contact stress by ensuring the proper geometry of the components and reducing friction by avoiding adhesion. The lubricant composition plays a key role in this prevention process, mainly through the physicochemical reactivity of its additives.

[0005] Anti-wear and extreme pressure additives containing sulfur, phosphorus, or borates are usually added, thereby imparting protective anti-seizure properties to the transmission oil. Other additives present in the lubricant composition may also have a positive or negative impact on this phenomenon.

[0006] Another advantage provided by the subject matter covered by the present invention is to avoid the use of any additives, and more particularly any extreme pressure anti-wear additives containing sulfur. It is desirable to limit or even completely eliminate sulfur in the transmission oil, especially for the transmission oil of electric vehicles, so as to limit the occurrence of corrosion phenomena and limit the conductivity value within the required range.

[0007] Advantageously, the object of the present invention relates to a composition that also does not contain zinc-based anti-wear additives.

[0008] Document EP3546550A1 discloses a composition comprising a reaction product of an acidic phosphate ester and a nitrogen compound.

[0009] Document EP3812445A1 discloses a composition comprising an acidic phosphate ester having a hydrocarbon group containing 1 to 6 carbon atoms.

[0010] The compounds described in these documents do not always provide satisfactory lubricating properties, especially in terms of durability and load-carrying capacity.

[0011] Accordingly, an object of the present invention is to provide a composition for lubricating components of a manual or automatic transmission, in particular the transmission gears of an internal combustion engine vehicle or preferably an electric vehicle, said composition exhibiting good durability and being free of any sulfur-based additives. Summary of the Invention

[0012] More precisely, the present invention relates to a lubricant composition comprising:

[0013] - at least one base oil;

[0014] - at least one additive having the formula (I):

[0015] [Chemical formula 1]

[0016]

[0017] wherein,

[0018] - R and R 1 are each independently selected from: a hydrogen atom; or a saturated or unsaturated straight-chain hydrocarbon group containing 8 to 20 carbon atoms; and at least one of the two groups R or R 1 is a saturated or unsaturated straight-chain hydrocarbon group containing 8 to 20 carbon atoms.

[0019] According to one embodiment, the hydrocarbon group is selected from alkyl and alkenyl.

[0020] Preferably, R and R 1 are each independently selected from straight-chain alkyl groups containing 8 to 18 carbon atoms.

[0021] Preferably, the lubricant composition comprises:

[0022] - phosphorus in an amount of 250 ppm to 1300 ppm by weight, preferably 400 ppm to 1400 ppm by weight, provided by one or more additives having the formula (I); and / or

[0023] - sulfur in an amount of less than 10 ppm by weight, preferably less than 5 ppm by weight, more preferably less than 1 ppm by weight.

[0024] According to a preferred embodiment, the lubricant composition of the present invention further additionally comprises at least one additive selected from: phosphites containing 1 to 24 carbon atoms; preferably phosphites containing 4 to 12 carbon atoms; preferably phosphites containing two alkyl groups each having 2 to 6 carbon atoms.

[0025] Preferably, relative to the total weight of the lubricant composition, the lubricant 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 one or more additives having formula (I).

[0026] According to a preferred embodiment, the lubricant composition of the present invention comprises:

[0027] - from 0.01% to 5% by weight, preferably from 0.02% to 2% by weight of one or more additives having formula (I); and

[0028] - from 0.05% to 5% by weight, preferably from 0.1% to 2% by weight of one or more additives selected from phosphites containing two alkyl groups each having 2 to 6 carbon atoms.

[0029] According to one embodiment of the present invention, the lubricant composition further additionally comprises at least one dispersant, preferably a borated dispersant, even more preferably a borated dispersant selected from borated succinimides, even more preferably borated polyisobutylene succinimides.

[0030] According to one embodiment of the present invention, the lubricant composition of the present invention comprises:

[0031] Relative to the total weight of the lubricant composition,

[0032] - at least 70% by weight, preferably from 75% to 99.5% by weight of one or more non-aqueous base oils;

[0033] - from 0.01% to 5% by weight, in particular from 0.02% to 2% by weight of one or more additives having formula (I);

[0034] - from 0.05% to 5% by weight, preferably from 0.1% to 2% by weight of one or more additives selected from phosphites containing 1 to 24 carbon atoms;

[0035] - optionally from 0.1% to 15% by weight, preferably from 1% to 10% by weight of one or more functional additives, said one or more functional additives being preferably selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

[0036] Preferably, the kinematic viscosity of one or more base oils at 100 °C ranges from 1.5 cSt to 35 cSt.

[0037] The present invention also equally relates to the use of the lubricant composition of the present invention for lubricating at least one mechanical component of a motor vehicle, said component being preferably present in the transmission assembly of the motor vehicle, preferably a gear of the motor vehicle.

[0038] The present invention also relates to the use of an additive in a lubricant composition containing at least one base oil for improving the load-carrying capacity of the lubricant composition, said additive having the formula (I):

[0039] [Chemical formula 1]

[0040]

[0041] wherein,

[0042] - R and R 1 are each independently selected from: a hydrogen atom; or a saturated or unsaturated straight-chain hydrocarbon group containing 8 to 20 carbon atoms; and at least one of the two groups R and R 1 is a saturated or unsaturated straight-chain hydrocarbon group containing 8 to 20 carbon atoms.

[0043] Preferably, the additive having the formula (I) is combined with an additive selected from phosphites containing 1 to 24 carbon atoms for the lubricant composition, preferably in the following proportions:

[0044] relative to the total weight of the lubricant composition,

[0045] - 0.01% to 5% by weight, preferably 0.02% to 2% by weight of one or more additives having the formula (I);

[0046] - 0.05% to 5% by weight, preferably 0.1% to 2% by weight of one or more additives selected from phosphites containing 1 to 24 carbon atoms.

[0047] Preferably, the lubricant composition to which the additive of the present invention is applied is as defined in the present invention. In particular, the lubricant composition to which the additive of the present invention is applied exhibits one or more of the following characteristics:

[0048] - The hydrocarbon group is selected from alkyl and alkenyl, and / or

[0049] - R and R 1 are each independently selected from straight-chain alkyl groups containing 8 to 18 carbon atoms, and / or

[0050] - The lubricant composition contains:

[0051] ο phosphorus provided by one or more additives having the formula (I) in an amount of 250 ppm to 1300 ppm by weight, preferably 400 ppm to 1400 ppm by weight; and / or

[0052] ο sulfur in an amount of less than 10 ppm by weight, preferably less than 5 ppm by weight, more preferably less than 1 ppm by weight; and / or

[0053] - The lubricant composition further comprises at least one additive selected from: phosphites having 1 to 24 carbon atoms; preferably phosphites having 4 to 12 carbon atoms; preferably phosphites having two alkyl groups each having 2 to 6 carbon atoms; and / or

[0054] - Relative to the total weight of the lubricant composition, the lubricant composition comprises 0.01% to 10% by weight, preferably 0.05% to 5% by weight, more preferably 0.1% to 3% by weight of one or more additives having the formula (I); and / or

[0055] - Relative to the total weight of the lubricant composition, the lubricant composition comprises:

[0056] ο 0.01% to 5% by weight, preferably 0.02% to 2% by weight of one or more additives having the formula (I); and

[0057] ο 0.05% to 5% by weight, preferably 0.1% to 2% by weight of one or more additives selected from phosphites having two alkyl groups each having 2 to 6 carbon atoms; and / or

[0058] - The lubricant composition further comprises at least one dispersant, preferably a borated dispersant, even more preferably a borated dispersant selected from borated succinimides, even more preferably borated polyisobutylene succinimides; and / or

[0059] - Relative to the total weight of the lubricant composition, the lubricant composition comprises:

[0060] ο at least 70% by weight, preferably 75% to 99.5% by weight of one or more non-aqueous base oils;

[0061] ο 0.01% to 5% by weight, especially 0.02% to 2% by weight of one or more additives having the formula (I);

[0062] ο 0.05% to 5% by weight, preferably 0.1% to 2% by weight of one or more additives selected from phosphites having 1 to 24 carbon atoms;

[0063] ο Optionally 0.1% to 15% by weight, preferably 1% to 10% by weight of one or more functional additives, the one or more functional additives preferably selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof;

[0064] - The kinematic viscosity of one or more base oils at 100 °C ranges from 1.5 cSt to 35 cSt.

[0065] An advantage of the lubricant composition of the present invention is that it has very good performance in reducing gear jamming (scuffing / scratching).

[0066] The lubricant composition of the present invention also exhibits good durability.

[0067] The lubricant composition of the present invention exhibits particularly satisfactory anti-wear performance even under heavier load conditions, even in the absence of sulfur-based additives and / or zinc-based additives.

[0068] In the remainder of this text, unless otherwise specified, the terms "between", "in the range from... to...", and "ranging from... to..." can be used interchangeably and are intended to indicate inclusion of the limits.

[0069] Unless otherwise specified, the amounts of the products are expressed by weight relative to the total weight of the products. Detailed Description

[0070] The present invention relates to a lubricant composition comprising:

[0071] - at least one base oil;

[0072] - at least one anti-wear additive having the formula (I):

[0073] Acidic phosphate type anti-wear additive having formula (I)

[0074] The lubricant composition of the present invention comprises at least one acidic phosphate ester type additive having the formula (I):

[0075] [Chemical Formula 1]

[0076]

[0077] Wherein:

[0078] - R and R 1 are each independently selected from: a hydrogen atom; or a saturated or unsaturated straight-chain hydrocarbon group containing 8 to 20 carbon atoms; and at least one of the two groups R and R 1 is a saturated or unsaturated straight-chain hydrocarbon group containing 8 to 20 carbon atoms.

[0079] For the purposes of the present invention, the term "straight-chain hydrocarbon group" should be understood to mean a straight-chain hydrocarbon chain (containing carbon atoms and hydrogen atoms) optionally containing one or more heteroatoms (such as an oxygen atom or a nitrogen atom).

[0080] Preferably, the hydrocarbon group is selected from alkyl and alkenyl.

[0081] According to one embodiment, R and R 1Each independently selected from a hydrogen atom or a straight-chain alkyl group having 8 to 20 carbon atoms. Preferably, R and R 1 Each independently selected from a straight-chain alkyl group having 8 to 18 carbon atoms. It should be understood that at least one of the R or R 1 groups is a straight-chain alkyl group.

[0082] The lubricant composition may optionally contain a mixture of compounds having the formula (I).

[0083] Preferably, the antiwear product having the formula (I) provides phosphorus in an amount of 250 ppm to 1300 ppm by weight.

[0084] Preferably, the antiwear additive having the formula (I) accounts for 0.01% to 10% by weight, more preferably 0.05% to 5% by weight, and even more preferably 0.1% to 3% by weight of the total weight of the lubricant composition of the present invention.

[0085] Phosphite type anti-wear additive

[0086] According to an advantageous embodiment of the present invention, the lubricant composition of the present invention comprises at least one antiwear additive selected from phosphites having 1 to 24 carbon atoms, preferably phosphites having 4 to 12 carbon atoms.

[0087] Advantageously, the phosphite-type antiwear additive is selected from phosphites having two alkyl groups, each alkyl group having 2 to 6 carbon atoms.

[0088] Particularly advantageously, the phosphite-type antiwear additive is dibutyl hydrogen phosphite.

[0089] According to one embodiment, the phosphite-type antiwear additive accounts for 0.05% to 5% by weight, preferably 0.1% to 2% by weight of the total weight of the lubricant composition of the present invention.

[0090] According to one embodiment of the present invention, the lubricant composition comprises:

[0091] Relative to the total weight of the lubricant composition,

[0092] - 0.01% to 5% by weight, preferably 0.02% to 2% by weight of one or more antiwear additives having the formula (I), wherein R and R 1 Each independently selected from: a hydrogen atom; or a saturated or unsaturated straight-chain hydrocarbon group having 8 to 20 carbon atoms; and at least one of the two groups R or R 1 is a saturated or unsaturated straight-chain hydrocarbon group having 8 to 20 carbon atoms; and

[0093] -0.05 wt% to 5 wt%, preferably 0.1 wt% to 2 wt% of one or more antiwear additives selected from phosphites containing 1 to 24 carbon atoms.

[0094] According to one embodiment of the present invention, the lubricant composition comprises:

[0095] Relative to the total weight of the lubricant composition,

[0096] -0.01 wt% to 5 wt%, preferably 0.02 wt% to 2 wt% of one or more antiwear additives having the formula (I), wherein R and R 1 are each independently selected from saturated or unsaturated straight-chain alkyl or alkenyl groups containing 8 to 20 carbon atoms, and

[0097] -0.05 wt% to 5 wt%, preferably 0.1 wt% to 2 wt% of one or more antiwear additives selected from phosphites containing 1 to 24 carbon atoms.

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

[0099] Relative to the total weight of the lubricant composition,

[0100] -0.01 wt% to 5 wt%, preferably 0.02 wt% to 2 wt% of one or more antiwear additives having the formula (I), wherein R and R 1 are each independently selected from straight-chain alkyl groups containing 8 to 18 carbon atoms;

[0101] and

[0102] -0.05 wt% to 5 wt%, preferably 0.1 wt% to 2 wt% of one or more antiwear additives selected from phosphites containing two alkyl groups each having 2 to 6 carbon atoms.

[0103] Base oil

[0104] The lubricant composition of the present invention comprises one or more base oils, the content of which is preferably at least 70 wt%, preferably 75 wt% to 99.5 wt%, more preferably 80 wt% to 99 wt%, and particularly preferably 85 wt% to 98 wt% relative to the total weight of the lubricant composition.

[0105] Preferably, the lubricant composition of the present invention comprises at least one base oil having a kinematic viscosity of 1.5 cSt to 35 cSt measured at 100 °C according to standard ASTM D445. Advantageously, the base oil of the lubricant composition of the present invention has a kinematic viscosity of 1.5 cSt to 35 cSt at 100 °C.

[0106] These base oils can be selected from the base oils commonly used in the lubricant field, such as mineral oils, synthetic oils or natural oils, animal oils or vegetable oils, or mixtures thereof. Generally, the base oil is a non-aqueous base oil.

[0107] It can be a mixture of multiple base oils, such as a mixture of two, three or four base oils.

[0108] The base oil of the lubricant composition contemplated by the present invention can in particular be a mineral oil or a synthetic oil belonging to Groups I to V according to the American Petroleum Institute (API) classification (or the equivalent classification according to the classification of the Association Technique de l'Industrie Européenne des Lubrifiants (ATIEL)), as shown in Table 1 below, or a mixture thereof.

[0109] [Table 1]

[0110]

[0111] Mineral base oils include various base oils obtained by atmospheric and vacuum distillation of crude oil and refined by processes such as solvent extraction, deasphalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrorefining.

[0112] Mixtures of synthetic oils and mineral oils that can be of biological origin can also be used.

[0113] For producing the compositions according to the practice of the present invention, there are generally no restrictions on the use of different base oils, as long as they must have properties suitable for use in the propulsion systems of electric vehicles or hybrid vehicles - especially in terms of viscosity, viscosity index or antioxidant properties.

[0114] The base oil of the composition according to the practice of the present invention can also be selected from synthetic oils, such as esters of certain carboxylic acids and alcohols; polyalphaolefins (PAO); and polyalkylene glycols (PAG) obtained by polymerization or copolymerization of alkylene oxides containing 2 to 8 carbon atoms, especially 2 to 4 carbon atoms.

[0115] PAO used as a base oil is prepared, for example, from monomers containing 4 to 32 carbon atoms, such as octene or decene. The weight average molecular weight of PAO can vary widely. Preferably, the weight average molecular weight of PAO is less than 600 Da. The weight average molecular weight of PAO can also be 100 Da to 600 Da, 150 Da to 600 Dda, or even 200 Da to 600 Da.

[0116] Advantageously, one or more base oils of the lubricant composition of the present invention can be selected from Group II or Group III base oils.

[0117] According to another embodiment, one or more base oils of the lubricant composition operated according to the present invention are selected from polyalphaolefins (PAOs), polyalkylene glycols (PAGs), and esters of carboxylic acids and alcohols.

[0118] Other supplementary additives

[0119] The lubricant composition of the present invention may further comprise various functional additives, which are different from the antiwear additives having formula (I) and phosphite-type antiwear additives defined in the present invention, but are lubricants suitable for motor vehicles, especially lubricants for manual or automatic transmissions of motor vehicles.

[0120] Such additives are known to those skilled in the art of motor vehicle lubrication and may be selected from detergents, dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents, viscosity index improvers (or viscosity modifiers), and mixtures thereof.

[0121] Advantageously, the composition of the present invention comprises at least one functional additive selected from detergents, dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents, viscosity index improvers (or viscosity modifiers), and mixtures thereof.

[0122] Generally, when these additional functional additives are present, these additional functional additives (in total) account for 1% to 30% by weight, preferably 1.5% to 25% by weight, and more preferably 2% to 20% by weight of the total weight of the lubricant composition.

[0123] These additives can be introduced individually and / or in the form of a mixture, similar to those already provided for commercial vehicle engine lubricant formulations on the market, the performance levels of which are defined by ACEA (Association des Constructeurs Européens d'Automobiles / European Automobile Manufacturers Association) and / or API (American Petroleum Institute), which are well known to those skilled in the art.

[0124] The lubricant composition of the present invention may comprise at least one antioxidant additive.

[0125] Antioxidant additives are generally used to retard the deterioration that occurs during the use of the composition. This deterioration can particularly lead to the formation of deposits, the presence of sludge, or an increase in the viscosity of the composition.

[0126] Antioxidant additives are particularly used as free radical inhibitors or peroxide destroyers (or scavengers). Among the commonly used antioxidant additives, phenolic antioxidant additives and amine antioxidant additives can be mentioned. The phenolic antioxidant additives can be ashless or can be in the form of neutral or basic metal salts. The antioxidant additives can be particularly selected from sterically hindered phenols; sterically hindered phenol esters; sterically hindered phenols containing a thioether bridge; diphenylamine, diphenylamine substituted by at least one C1-C12 alkyl group, N,N'-dialkyl-aryldiamine; and mixtures thereof.

[0127] Preferably, according to the present invention, the sterically hindered phenol is selected from compounds containing a phenol group, wherein at least one ortho-carbon adjacent to the carbon bearing an alcohol functional group is substituted by at least one C1-C 10 alkyl group, preferably a C1-C6 alkyl group, preferably a C4 alkyl group, preferably a tert-butyl group.

[0128] Amine compounds are another class of antioxidant additives that can be used and can be used in combination with phenolic antioxidant additives. Examples of amine compounds include aromatic amines, such as aromatic amines having the formula NR 10 R 11 R 12 wherein: R 10 represents an optionally substituted aliphatic group or aromatic group; R 11 represents an optionally substituted aromatic group; R 12 represents a hydrogen atom, an alkyl group, an aryl group or a group having the formula R 13 S(O) z R 14 wherein: R 13 represents an alkylene or alkenylene group, R 14 represents an alkyl group, an alkenyl group or an aryl group, and z represents 0, 1 or 2.

[0129] Alkylphenol sulfides or their alkali metal and alkaline earth metal salts can also be used as antioxidant additives.

[0130] Copper compounds constitute another class of antioxidant additives, such as salts of copper with carboxylic acids, copper phenolates and copper acetylacetonate. Copper I and II salts, succinate salts or succinic anhydride salts can also be used.

[0131] The lubricant composition of the present invention can contain all types of antioxidant additives known to those skilled in the art.

[0132] Advantageously, the lubricant composition of the present invention contains at least one ashless antioxidant additive.

[0133] The lubricant composition of the present invention can contain at least one antioxidant additive in an amount of 0.5% to 2% by weight based on the total weight of the composition.

[0134] The lubricant composition of the present invention may also contain at least one detergent additive.

[0135] Detergent additives generally reduce the formation of surface deposits on metal components by dissolving the by-products of oxidation and combustion.

[0136] Detergent additives that can be used in the lubricant composition of the present invention are generally known to those skilled in the art. The detergent additive may be an anionic compound comprising a lipophilic long hydrocarbon chain and a hydrophilic top. The associated cation may be a metal cation of an alkali metal or an alkaline earth metal.

[0137] The detergent additive is preferably selected from the alkali metal or alkaline earth metal salts of carboxylic acids; salicylates; naphthenates and phenates. The alkali metals and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

[0138] These metal salts generally contain stoichiometric amounts of metal or even excess metal, i.e., the amount of metal is greater than stoichiometric. They are thus overbased detergent additives; the excess metal that imparts overbased characteristics to the detergent additive is generally in the form of a metal salt insoluble in oil, such as carbonate, hydroxide, oxalate, acetate, glutamate, preferably carbonate.

[0139] The lubricant composition according to the present invention may contain, for example, from 0.5% to 4% by weight of the detergent additive relative to the total weight of the composition.

[0140] In addition, the lubricant composition of the present invention may contain at least one dispersant. Generally, dispersants are used to ensure that insoluble solid contaminants composed of oxidation by-products formed during the use of the lubricant composition remain in suspension and are discharged.

[0141] The dispersant may be selected from: Mannich bases; succinimide-type compounds, such as optionally borated polyisobutylene succinimide (PIBSI); or borated dispersants other than succinimides; preferably borated dispersants; even more preferably borated succinimide dispersants, especially borated PIBSI.

[0142] The lubricant composition of the present invention may contain, for example, from 0.2% to 10% by weight of one or more dispersants relative to the total weight of the composition.

[0143] The lubricant composition of the present invention may also additionally contain at least one defoamer.

[0144] The defoamer may be selected from silicone.

[0145] The lubricant composition of the present invention may comprise from 0.01% to 2% by weight or from 0.01% to 5% by weight, preferably from 0.1% to 1.5% by weight or from 0.1% to 2% by weight, of an antifoaming agent relative to the total weight of the composition.

[0146] The lubricant composition of the present invention may further comprise at least one pour point depressant (PPD) additive.

[0147] By slowing the formation of paraffin crystals, pour point depressant additives generally improve the cold behavior of the composition. Examples of pour point depressant additives that may be used include polyalkyl methacrylates, polyacrylates, polyaryl amides, polyalkyl phenols, polyalkyl naphthalenes, and alkylated polystyrenes.

[0148] The lubricant composition of the present invention may further comprise at least one viscosity index improver (or VI modifier). Examples of VI improvers that may be cited include polymethacrylates, polyisobutene, or fatty acid esters. If present, these additives may account for from 1% to 25% by weight of the total weight of the lubricant composition.

[0149] Preferably, the lubricant composition of the present invention does not contain zinc-containing antiwear additives.

[0150] For the formulation of such lubricant compositions, one or more antiwear additives of the present invention may be added to a base oil or a base oil mixture, and then any other supplementary additives may be added.

[0151] Alternatively, one or more antiwear additives of the present invention may be added to an existing conventional lubricant formulation, which particularly comprises one or more base oils and optionally other supplementary additives.

[0152] Alternatively, one or more antiwear additives of the present invention may be combined with one or more additional additives (if present), and the resulting "additive package" may be added to a base oil or a base oil mixture.

[0153] Advantageously, the lubricant composition of the present invention has a kinematic viscosity measured at 40 °C according to standard ASTM D445 of 5 mm 2 / s to 300 mm 2 / s, particularly 10 mm 2 / s to 25 mm 2 / s.

[0154] Advantageously, the lubricant composition of the present invention has a kinematic viscosity measured at 100 °C according to standard ASTM D445 of 1 mm 2 / s to 20 mm 2 / s, particularly 2 mm 2 / s to 15 mm 2 / s.

[0155] Preferably, the lubricant composition comprises from 400 ppm to 1400 ppm by weight of phosphorus, advantageously provided by an antiwear agent having the formula (I) in an amount of from 250 ppm to 1300 ppm by weight.

[0156] Preferably, the lubricant composition is substantially sulfur-free, preferably completely sulfur-free.

[0157] In particular, the lubricant composition of the present invention preferably does not contain any sulfur-containing additives.

[0158] Thus, the lubricant composition of the present invention generally contains less than 10 ppm by weight of sulfur, even less than 5 ppm by weight of sulfur, or even less than 1 ppm by weight of sulfur.

[0159] According to a specific embodiment, the lubricant composition of the present invention comprises or consists essentially of:

[0160] - a base oil or a mixture of base oils;

[0161] - an antiwear additive having the formula (I):

[0162] - an antiwear additive optionally selected from phosphites containing 1 to 24 carbon atoms;

[0163] - optionally one or more additional additives selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

[0164] According to a specific embodiment, the lubricant composition of the present invention comprises or consists essentially of:

[0165] Relative to the total weight of the lubricant composition,

[0166] - at least 70% by weight, preferably 75% to 99.5% by weight of one or more base oils;

[0167] - from 0.01% to 10% by weight, in particular from 0.05% to 5% by weight of one or more antiwear additives having the formula (I);

[0168] - optionally from 0.05% to 5% by weight, in particular from 0.1% to 2% by weight of one or more antiwear additives selected from phosphites containing 1 to 24 carbon atoms;

[0169] - optionally from 0.1% to 15% by weight, preferably from 1% to 10% by weight of one or more functional additives, said one or more functional additives preferably being selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

[0170] According to a specific embodiment of the lubricant composition, the lubricant composition of the present invention comprises or consists essentially of the following:

[0171] Based on the total weight of the lubricant composition,

[0172] - at least 70% by weight, preferably 75% to 99.5% by weight of one or more base oils;

[0173] - 0.01% to 5% by weight, especially 0.02% to 2% by weight of one or more antiwear additives having the formula (I);

[0174] - 0.05% to 5% by weight, preferably 0.1% to 2% by weight of one or more antiwear additives selected from phosphites containing 1 to 24 carbon atoms;

[0175] - optionally 0.1% to 15% by weight, preferably 1% to 10% by weight of one or more functional additives, said one or more functional additives being preferably selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

[0176] According to a specific embodiment, the lubricant composition of the present invention comprises:

[0177] Based on the total weight of the lubricant composition,

[0178] - at least 70% by weight, preferably 75% to 99.5% by weight of one or more base oils;

[0179] - 0.01% to 5% by weight, especially 0.02% to 2% by weight of one or more additives having the formula (I);

[0180] - 0.05% to 5% by weight, preferably 0.1% to 2% by weight of one or more additives selected from phosphites containing 1 to 24 carbon atoms, preferably 4 to 12 carbon atoms, preferably selected from phosphites containing two alkyl groups each having 2 to 6 carbon atoms.

[0181] - optionally 0.1% to 15% by weight, preferably 1% to 10% by weight of one or more functional additives, said one or more functional additives being preferably selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

[0182] According to a specific embodiment, the lubricant composition of the present invention comprises or consists essentially of the following:

[0183] relative to the total weight of the lubricant composition

[0184] - at least 70% by weight, preferably 75% to 99.5% by weight, of one or more base oils;

[0185] - 0.01% to 5% by weight, in particular 0.02% to 2% by weight, of one or more antiwear additives having the formula (I);

[0186] - 0.05% to 5% by weight, preferably 0.1% to 2% by weight, of one or more antiwear additives selected from phosphites containing 1 to 24 carbon atoms;

[0187] - optionally 0.1% to 15% by weight, preferably 1% to 10% by weight, of one or more functional additives, said one or more functional additives preferably selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof;

[0188] The composition contains less than 10 ppm of sulfur by weight.

[0189] According to a specific embodiment, the lubricant composition of the present invention comprises or consists essentially of:

[0190] relative to the total weight of the lubricant composition

[0191] - at least 70% by weight, preferably 75% to 99.5% by weight, of one or more base oils;

[0192] - 0.01% to 5% by weight, preferably 0.02% to 2% by weight, of one or more antiwear additives having the formula (I), wherein R and R 1 are each independently selected from straight-chain alkyl groups containing 8 to 18 carbon atoms;

[0193] - 0.05% to 5% by weight, preferably 0.1% to 2% by weight, of one or more antiwear additives selected from phosphites containing two alkyl groups each having 2 to 6 carbon atoms.

[0194] - optionally 0.1% to 15% by weight, preferably 1% to 10% by weight, of one or more functional additives, said one or more functional additives preferably selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

[0195] According to a specific embodiment, the lubricant composition of the present invention comprises or consists essentially of:

[0196] relative to the total weight of the lubricant composition

[0197] - At least 70% by weight, preferably 75% to 99.5% by weight, of one or more base oils;

[0198] - 0.01% to 5% by weight, especially 0.02% to 2% by weight, of one or more antiwear additives having the formula (I);

[0199] - 0.05% to 5% by weight, preferably 0.1% to 2% by weight, of one or more antiwear additives selected from phosphites containing 1 to 24 carbon atoms;

[0200] - 0.5% to 5% by weight, preferably 0.1% to 2% by weight, of one or more dispersants, said one or more dispersants preferably selected from borated dispersants;

[0201] - Optionally 0.1% to 10% by weight, preferably 0.5% to 5% by weight, of one or more functional additives, said one or more functional additives preferably selected from antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

[0202] The object of the present invention also relates to the use of the lubricant composition of the present invention for lubricating a motor vehicle transmission, in particular the gears of a transmission. These transmissions can be manual or automatic transmissions.

[0203] Preferably, the lubricant composition of the present invention is used to reduce wear of mechanical components of a motor vehicle transmission, in particular wear of motor vehicle gears. Thus, according to this embodiment, the lubricant composition of the present invention provides a method for reducing wear of transmission gears.

[0204] Preferably, the lubricant composition of the present invention is used for spalling or scratching of mechanical components (in particular motor vehicle gears) of a motor vehicle transmission.

[0205] According to an advantageous embodiment, the lubricant composition of the present invention is used to simultaneously reduce wear and reduce spalling or scratching of mechanical components (in particular motor vehicle gears) of a motor vehicle transmission.

[0206] According to another aspect thereof, the present invention also relates to a lubrication method for lubricating at least one component of a motor vehicle transmission, in particular a motor vehicle gear, the method comprising at least one step of bringing at least said component into contact with the above-mentioned lubricant composition.

[0207] According to another aspect thereof, the present invention also relates to a process for enhancing the durability of a lubricant composition, the process comprising the step of mixing at least one antiwear additive having the formula (I) as defined in the present invention with at least one base oil. Preferably, the antiwear additive having the formula (I) is further mixed with an antiwear additive selected from phosphites containing 1 to 24 carbon atoms.

[0208] All the features and preferences described for the lubricant composition and its uses of the present invention are equally applicable to the said method and process.

[0209] According to the present invention, the particularly advantageous or preferred features of the composition of the present invention may define the equally particularly advantageous or preferred uses of the present invention.

[0210] The present invention is now illustrated by the following examples, which are provided for illustrative purposes only and are not intended to limit the present invention.

[0211] Examples

[0212] Example 1: Preparation of a lubricant composition

[0213] A lubricant composition was prepared by mixing the components at a temperature of about 40 °C according to methods known to those skilled in the art. The lubricant compositions prepared and tested are shown in detail in Tables 2 and 3 below.

[0214] The contents of elemental phosphorus and sulfur were calculated based on the elemental contents in the components and are listed in Table 2 in weight ppm.

[0215] The viscosity of the lubricant compositions tested was approximately 4.5 cSt at 100 °C measured according to standard ASTM D445.

[0216] [Table 2]

[0217] CC1 CC2 CI1 CI2 CI3 CI4 Base oil 94.65％ 94.65％ 94.65％ 95.15％ 95.4％ 94.75％ Anti-wear agent I1 1％ 0.5％ 0.25％ 1％ Anti-wear agent P1 0.1％ 0.1％ 0.1％ 0.1％ 0.1％ Anti-wear agent C1 1％ Anti-wear agent C2 1％ Antioxidant 1.4％ 1.4％ 1.4％ 1.4％ 1.4％ 1.4％ Anti-corrosion agent 0.05％ 0.05％ 0.05％ 0.05％ 0.05％ 0.05％ Dispersant 2.25％ 2.25％ 2.25％ 2.25％ 2.25％ 2.25％ Additive package 0.55％ 0.55％ 0.55％ 0.55％ 0.55％ 0.55％ Total (wt%) 100％ 100％ 100％ 100％ 100％ 100％ Total P content (ppm) 1120 1460 1380 770 465 1220 P content from (I) or C1 or C2 (ppm) 970 1310 1230 620 315 1070 S content (ppm) 0 0 0 0 0 0

[0218] In the compositions of Table 2:

[0219] - The base oil is a Group III base oil;

[0220] - The antiwear agent I1 has the formula (I), where R and R 1 are two straight-chain C8 alkyl chains;

[0221] - The antiwear agent P1 is dibutyl hydrogen phosphite;

[0222] - The antiwear agent C1 does not have the formula (I) since it is an acidic phosphate with a branched chain containing 8 carbon atoms;

[0223] - The antiwear agent C2 does not have the formula (I) since it is an acidic phosphate with a chain containing 5 carbon atoms;

[0224] - The dispersant is a boric acid-modified PIBSI dispersant, which can provide about 85 ppm of boron;

[0225] - The antioxidant includes phenolic antioxidants and / or amine antioxidants;

[0226] - The anti-corrosion agent is a triazole derivative;

[0227] - The additive component includes a pour point depressant and an antifoaming agent / defoaming agent.

[0228] Example 2: Test and study on the performance of the lubricant composition

[0229] The anti-seizure load-carrying capacity of the lubricant composition described in Table 2 was tested using the FZG A10 / 16.6R / 90 method (according to the revised standard CEC-L-84-02). The results are shown in Table 4 below.

[0230] The average coefficient of friction was measured on a Mini Traction Machine (MTM) under the following conditions:

[0231] - Load = 5 N;

[0232] - Rolling speed / driving speed = 3 mm / s;

[0233] - Temperature = 90 °C;

[0234] Duration = 10 minutes;

[0235] SSR (Sliding to Rolling Ratio) = 330%.

[0236] [Table 4]

[0237] CC1 CC2 CI1 CI2 CI3 CI4 FZG 4 5 8 7 7 7 Coefficient of friction 0.130 0.122 0.108 0.107 0.112 0.098

[0238] The compositions CI1 to CI4 of the present invention exhibit very good load-carrying capacity. These load-carrying capacity values (FZG) prove that the lubricant composition has very high durability and is particularly suitable for use in transmission devices.

[0239] The compositions CI1 to CI4 of the present invention also exhibit a lower average coefficient of friction, thus proving their excellent lubrication performance.

[0240] The anti-wear agent having formula (I) defined in the present invention provides a way to improve the performance level of the lubricant composition. More specifically, the anti-wear agent having formula (I) defined in the present invention provides more excellent performance compared to the prior art anti-wear agents C1 and C2.

Claims

1. A lubricant composition comprising: - at least one base oil; - at least one additive having the formula (I): [Chemical formula 1] Wherein, R and R 1 each independently selected from: a hydrogen atom; or a saturated or unsaturated straight-chain hydrocarbon group having 8 to 20 carbon atoms, and optionally containing one or more heteroatoms; and at least one of the two groups R or R 1 is a saturated or unsaturated straight-chain hydrocarbon group having 8 to 20 carbon atoms.

2. The lubricant composition according to claim 1, wherein, The hydrocarbon group is selected from alkyl and alkenyl groups.

3. The lubricant composition according to any one of the preceding claims, wherein, R and R 1 Each independently selected from straight-chain alkyl groups having 8 to 18 carbon atoms.

4. The lubricant composition according to any one of the preceding claims, comprising: - phosphorus in an amount of 250 ppm to 1300 ppm by weight, preferably 400 ppm to 1400 ppm by weight, provided by one or more additives having the formula (I); and / or - sulfur in an amount of less than 10 ppm by weight, preferably less than 5 ppm by weight, more preferably less than 1 ppm by weight.

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

6. The lubricant composition according to the previous claim, comprising, relative to the total weight of the lubricant composition, 0.01% to 10% by weight, preferably 0.05% to 5% by weight, more preferably 0.1% to 3% by weight of one or more additives having the formula (I).

7. The lubricant composition according to any one of the preceding claims, comprising, relative to the total weight of the lubricant composition: - 0.01% to 5% by weight, preferably 0.02% to 2% by weight of one or more additives having the formula (I); and - 0.05% to 5% by weight, preferably 0.1% to 2% by weight of one or more additives selected from phosphites containing two alkyl groups each having 2 to 6 carbon atoms.

8. The lubricant composition according to any one of the preceding claims, further comprising at least one dispersant, preferably a borated dispersant, even more preferably a borated dispersant selected from borated succinimides, even more preferably borated polyisobutylene succinimides.

9. The lubricant composition according to any one of the preceding claims, comprising: Relative to the total weight of the lubricant composition, - at least 70% by weight, preferably 75% to 99.5% by weight of one or more base oils; - 0.01% to 5% by weight, especially 0.02% to 2% by weight of one or more additives having the formula (I); - 0.05% to 5% by weight, preferably 0.1% to 2% by weight of one or more additives selected from phosphites containing 1 to 24 carbon atoms, preferably 4 to 12 carbon atoms, preferably phosphites containing two alkyl groups each having 2 to 6 carbon atoms.

10. The lubricant composition according to any one of the preceding claims, comprising: Relative to the total weight of the lubricant composition, - at least 70% by weight, preferably 75% to 99.5% by weight of one or more non-aqueous base oils; - 0.01% to 5% by weight, especially 0.02% to 2% by weight of one or more additives having the formula (I); - 0.05% to 5% by weight, preferably 0.1% to 2% by weight, of one or more additives selected from phosphites containing 1 to 24 carbon atoms; - Optionally, 0.1% to 15% by weight, preferably 1% to 10% by weight, of one or more functional additives, said one or more functional additives preferably selected from dispersants, antioxidants, pour point depressants, defoamers or antifoaming agents and mixtures thereof.

11. The lubricant composition according to any one of the preceding claims, wherein, The kinematic viscosity of the one or more base oils at 100 °C is from 1.5 cSt to 35 cSt.

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

13. Use of an additive in a lubricant composition containing at least one base oil for improving the load-carrying capacity of said lubricant composition, said additive having the formula (I): [Chemical formula 1] wherein, -R and R 1 each independently selected from: a hydrogen atom; or a saturated or unsaturated straight-chain hydrocarbon group having 8 to 20 carbon atoms, and optionally containing one or more heteroatoms; and at least one of the two groups R or R 1 is a saturated or unsaturated straight-chain hydrocarbon group having 8 to 20 carbon atoms.

14. The use according to claim 13, wherein, The additive having the formula (I) is combined with an additive selected from phosphites containing 1 to 24 carbon atoms for said lubricant composition, preferably in the following proportions: Based on the total weight of the lubricant composition, - 0.01% to 5% by weight, preferably 0.02% to 2% by weight, of one or more additives having the formula (I); - 0.05% to 5% by weight, preferably 0.1% to 2% by weight, of one or more additives selected from phosphites containing 1 to 24 carbon atoms.

15. The use according to claim 13 or 14, wherein, The lubricant composition is as defined in any one of claims 2 to 11.

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