Use of monoesters in vehicle transmission lubricating compositions

Abstract

The present invention relates to the use of a composition comprising 1-methylheptyl laurate as a transmission lubricating composition.

Description

[Technical Field]

[0001] The present invention relates to the field of lubricating compositions, more particularly to lubricating compositions for the transmissions of vehicles having internal combustion engines (gearboxes and / or axles), and to the transmissions, more particularly reduction gears, of the propulsion systems of electric or hybrid vehicles. The present invention more particularly relates to the use of monoesters to improve the efficiency performance of the transmissions in internal combustion engines and the reduction gears of electric motors. [Background technology]

[0002] Lubricating compositions, also known as "lubricants," are generally used in different vehicle components with the primary purpose of reducing frictional forces between different metal parts moving within the components, more specifically, the engine, transmission, and hydraulic circuits. This, in turn, is effective in preventing premature wear or further damage to such components, particularly their surfaces. For this purpose, lubricating compositions are traditionally composed of a base oil, which is generally associated with a number of additives, such as friction modifying additives, specifically designed to stimulate the lubricating properties of the base oil and to provide additional performance.

[0003] A lubricating composition for a transmission (e.g., gearbox or axle) must meet many requirements, particularly with respect to the stringent specifications imposed by automobile manufacturers. More specifically, it must have satisfactory properties with respect to viscosity, viscosity-temperature resistance, low temperature performance, etc., suitable for its implementation in the transmission components of a vehicle, particularly the gearbox or axle.

[0004] The evolution of international standards for reducing CO2 emissions as well as energy consumption is encouraging car manufacturers to offer alternative solutions to the internal combustion engine.

[0005] One of the solutions identified by car manufacturers is to replace the internal combustion engine with an electric motor. Therefore, research to reduce CO2 emissions has led many car companies to develop electric vehicles.

[0006] An "electric vehicle" as defined by this invention refers to a vehicle that includes an electric motor as its sole means of propulsion, while a hybrid vehicle includes an internal combustion engine and an electric motor as its combined means of propulsion.

[0007] The "propulsion system" as defined by the present invention refers to a system comprising the mechanical components necessary for the propulsion of an electric vehicle. The propulsion system thus encompasses, more specifically, an electric motor with a rotor-stator assembly, a power electronics system (dedicated to speed regulation), a transmission (also called a reduction gear, and when the reduction gear is connected to the motor, this refers to the motor reduction gear), and a battery. The battery thus generally consists of a set of electrical capacitors called cells.

[0008] There is a need to provide lubricating compositions of renewable plant origin that have a low environmental impact.

[0009] Furthermore, current environmental concerns, particularly those aimed at reducing carbon dioxide emissions, have created an urgent need to reduce fuel consumption in motor vehicles. Thus, lubricating compositions are known to be an effective means of influencing fuel consumption through their influence on the frictional forces occurring between different components of a motor vehicle. Therefore, there is a need to develop lubricants that reduce friction in gearboxes and axle differentials.

[0010] Improving the "fuel saving" characteristics of transmission lubricants while maintaining the required high level of performance remains a challenge.

[0011] The object of the present invention is to propose a monoester that can be completely biosourced and is suitable for improving the efficiency performance of the transmissions of internal combustion engines as well as the reduction gears of electric motors. Summary of the Invention

[0012] The subject of the present invention therefore relates to the use of a composition comprising 1-methylheptyl laurate as a lubricating composition for transmissions.

[0013] According to one embodiment, a lubricating composition comprising 1-methylheptyl laurate is used in the transmission of a heat engine and / or in the reduction gear of an electric motor.

[0014] According to one embodiment, a lubricating composition comprising 1-methylheptyl laurate is used to improve the efficiency of a transmission.

[0015] According to one embodiment, a lubricating composition comprising 1-methylheptyl is used to reduce fuel consumption of a vehicle equipped with transmission components, particularly gearboxes and / or axles, lubricated with said lubricating composition.

[0016] According to one embodiment, a lubricating composition comprising 1-methylheptyl laurate is used to improve the efficiency performance of reduction gears in electric motors.

[0017] In one embodiment, a lubricating composition comprising 1-methylheptyl laurate is used to increase the autonomy of a battery in an electric or hybrid vehicle.

[0018] Preferably, the lubricating composition comprises 5 to 50 wt. % 1-methylheptyl laurate, preferably 10 to 40 wt. % 1-methylheptyl laurate, based on the total weight of the lubricating composition.

[0019] Preferably, the lubricating composition comprises, based on the total weight of the lubricating composition, 5 to 50% by weight, preferably 10 to 40% by weight, of 1-methylheptyl; 50 to 95% by weight, preferably 60 to 90% by weight, of one or more base oils other than 1-methylheptyl laurate; Includes.

[0020] Preferably, the lubricating composition has a viscosity of 1 to 6 mm at 100°C. 2 / s range, preferably 1 to 4 mm 2 / s range of kinematic viscosity.

[0021] Preferably, the 1-methylheptyl laurate has a carbon content of biological origin of at least 90% by weight based on the total weight of carbon atoms.

[0022] According to one embodiment, the lubricating composition comprises, in addition to 1-methylheptyl laurate, at least one additive selected from antioxidants, additives which improve the viscosity index, pour point depressants, antifoam agents, anticorrosion agents, antiwear and / or extreme pressure additives, friction modifiers, detergents, dispersants and mixtures thereof, more particularly from antioxidants, pour point depressants, antifoam agents and anticorrosion agents.

[0023] Preferably, the additive(s) represent 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. %, based on the total weight of the lubricating composition. [Problem to be solved by the invention]

[0024] The object of the invention is precisely to improve the efficiency performance of transmissions in internal combustion engines and of reduction gears in electric motors. [Means for solving the problem]

[0025] The invention thereby aims to improve the "fuel saving" characteristics of an internal combustion engine and to extend the duration of the autonomy of the battery for the electric motor.

[0026] Other characteristics, variants and advantages of the implementation of the monoesters of the invention will become apparent on reading the following description and examples, given by way of illustration of the invention, but without limiting it.

[0027] Hereinafter, in the text, the expressions "included between ... and ...", "ranging from ... to ..." and "varying from ... to ..." are equivalent and mean the inclusion of the limiting values, unless otherwise specified.

[0028] Unless otherwise specified, the expression "comprising a" is to be understood as "comprising at least one." [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic diagram of an electric or hybrid vehicle propulsion system.

[0030] Detailed Description of the Invention First, the present invention relates to the use of 1-methylheptyl laurate in transmission lubricating compositions.

[0031] The present invention relates to the use of a composition comprising 1-methylheptyl laurate as a transmission lubricating composition.

[0032] 1-Methylheptyl laurate can be obtained by the esterification reaction of lauric acid with octan-2-ol.

[0033] Preferably, the lauric acid and / or octan-2-ol are of biological origin. Biogenic octan-2-ol can be obtained by decomposing ricinoleic acid.

[0034] Thereby, preferably, the 1-methylheptyl laurate has a carbon content of biological origin of at least 90% by weight, preferably at least 95% by weight, advantageously 100% by weight, relative to the total weight of carbon atoms.

[0035] Within the framework of the present invention, the content of carbon of biological origin can be determined according to the standard ASTM D6866.

[0036] The 1-methylheptyl laurate, also referred to as the monoester, of the present invention is used in transmission lubricating compositions. Other base oil(s)

[0037] The lubricating compositions used according to the present invention may contain, in addition to the monoester according to the present invention, one or more base oils different from the monoester according to the present invention.

[0038] The base oils optionally present in the lubricating compositions according to the invention are suitably selected for their compatibility with the monoesters used according to the invention.

[0039] There may be a mixture of several base oils, for example a mixture of two, three or four base oils.

[0040] Preferably, the base oil or other mixture of base oils used in the lubricating composition according to the invention has a viscosity of 1.5 to 8 mm, measured at 100°C according to standard ASTM D445. 2 / s, especially 1.5~6.1mm 2 / s, more specifically 1.5 to 4.1 mm 2 / s, and more specifically 1.5 to 2.1 mm 2 The viscosity may be in the range of 1 / s.

[0041] The base oil may be selected from mineral or synthetic oils, or mixtures thereof, belonging to groups I to V according to the classes defined by the API classification (or its equivalent according to the ATIEL classification) and shown in Table 1 below.

[0042] [Table 1]

[0043] Mineral base oils include any type of base oil obtained by atmospheric and vacuum distillation of crude oil followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing.

[0044] Mixtures of synthetic and mineral oils, which may be biosourced, may also be used.

[0045] There are generally no restrictions on the use of different additional base oils to prepare the lubricating composition, but the composition should preferably have properties, particularly with respect to viscosity index, sulfur content or oxidation resistance, that make it suitable for use in the propulsion system of an electric or hybrid vehicle.

[0046] The base oil may further be selected from synthetic oils such as specific carboxylic acid esters and alcohol esters different from the diesters defined in accordance with the present invention, among polyalphaolefins (PAOs) and among polyalkylene glycols (PAGs) obtained by polymerization or copolymerization of alkylene oxides containing 2 to 8 carbon atoms, more particularly 2 to 4 carbon atoms.

[0047] The PAOs used as base oils are derived, for example, from monomers containing from 4 to 32 carbon atoms, such as octene or decene.

[0048] The weight average molecular weight of the PAO can vary widely. Preferably, the weight average molecular weight of the PAO is less than 600 Da. The weight average molecular weight of the PAO can further range from 100 to 600 Da, 150 to 600 Da, or even 200 to 600 Da.

[0049] For example, 1.5 to 8 mm measured at 100°C according to standard ASTM D445 2 PAOs used in the context of the present invention having kinematic viscosities in the range of 1 / s are marketed by Ineos under the trademarks Durasyn® 162, Durasyn® 164, Durasyn® 166 and Durasyn® 168.

[0050] Advantageously, the additional base oil is chosen from polyalphaolefins (PAO).

[0051] Those skilled in the art will be able to adjust the content of auxiliary base oil(s) present in the lubricating composition according to the invention.

[0052] According to one embodiment, the composition according to the invention may comprise from 5 to 95% by weight, preferably from 50 to 95% by weight, otherwise from 60 to 90% by weight, of one or more base oils different from the monoesters according to the invention, relative to the total weight of said composition. additives

[0053] The lubricating compositions according to the present invention may further comprise one or more additives known to those skilled in the art in the field of transmission lubrication, more particularly in the field of internal combustion engines and electric or hybrid vehicle propulsion systems.

[0054] The additives that can be incorporated into the compositions according to the invention can be chosen from antioxidants, pour point depressants, antifoams, anticorrosion agents, antiwear and / or extreme pressure additives, friction modifiers, detergents, dispersants and mixtures thereof, more particularly from antioxidants, pour point depressants, antifoams and anticorrosion agents.

[0055] Preferably, the lubricating composition according to the present invention may further comprise one or more additives selected from antioxidants, antifoam agents, pour point improvers, viscosity index improvers, and corrosion inhibitors.

[0056] The addition of one or more additives selected from anti-wear additives, friction modifiers, detergents, extreme pressure additives and dispersants also proves advantageous within the framework of the use of the lubricating composition according to the invention as a multifunctional fluid, for example for cooling batteries and / or electronic power components, and for lubricating parts of the propulsion system, e.g. the transmission, of electric or hybrid vehicles.

[0057] It will be understood that the nature and amount of additives used will be selected so as not to affect the properties of the lubricating composition imparted by the monoesters according to the present invention.

[0058] Such additives may be introduced separately and / or in similar mixtures with additives already commercially available for commercial lubricant formulations for vehicle engines, with performance levels defined by ACEA (European Automobile Manufacturers Association) and / or API (American Petroleum Institute) well known to those skilled in the art.

[0059] The additive(s) may be present in the lubricating composition according to the invention in a content of up to 20% by weight, more particularly from 0.01 to 20% by weight, preferably from 0.1 to 15% by weight, otherwise preferably from 0.5 to 10% by weight, relative to the total weight of the composition.

[0060] Thus, the lubricating composition according to the present invention may comprise at least one antioxidant additive.

[0061] Thus, according to one of its aspects, the present invention relates to a lubricating composition, more particularly a lubricating composition suitable for lubricating a transmission, more particularly a transmission of an internal combustion engine or of the propulsion system of an electric or hybrid vehicle, said composition comprising (i) at least one monoester according to the present invention and (ii) at least one antioxidant additive.

[0062] Antioxidant additives generally make it possible to slow down the decomposition of the composition during use, which is most often seen in the formation of deposits, the presence of sludge, or an increase in the viscosity of the composition.

[0063] Antioxidant additives act, in particular, as radical inhibitors or destroyers of hydroperoxides. Commonly used antioxidant additives include phenolic antioxidants, amine antioxidant additives, and phosphorus-sulfur antioxidant additives. Some of these antioxidant additives, such as phosphorus-sulfur antioxidant additives, may generate ash. Phenolic antioxidant additives may be ashless or in the form of neutral or basic metal salts. Antioxidant additives include, in particular, sterically hindered phenols, sterically hindered phenol esters, and sterically hindered phenols containing thioether bridges, diphenylamines, and esters of at least one C1-C 12 It can be selected from diphenylamines substituted with alkyl moieties, N,N'-dialkyl-aryl-diamines, and mixtures thereof.

[0064] Preferentially, according to the invention, the sterically hindered phenol is one in which at least one of the carbon atoms adjacent to the carbon atom bearing the alcohol functional group has at least one C1-C 10 They are selected from compounds containing a phenol group substituted with an alkyl group, preferentially a C1 to C6 alkyl group, preferentially a C4 alkyl group, preferentially a tert-butyl group.

[0065] Amine compounds are another class of antioxidant additives that may optionally be used in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, such as those of the formula NR 4 R 5 R 6 (In the formula, R 4 represents an aliphatic group or an optionally substituted aromatic group, and R 5 represents an optionally substituted aromatic group, and R 6 is a hydrogen atom, an alkyl group, an aryl group or a group of the formula R 7 S(O) z R 8 (In the formula, R 7 represents an alkylene or alkenylene group, and R 8 represents an alkyl group, an alkenyl group, or an aryl group, and z is 0, 1, or 2.

[0066] Sulfur alkylphenols or their alkali or alkaline earth metal salts may also be used as antioxidant additives.

[0067] Another class of antioxidant additives is the class of copper compounds, such as copper thio- or dithiophosphates, copper salts and carboxylates, copper dithiocarbamates, copper sulfonates, copper phenates, copper acetylacetonates. Copper salts I and II, succinates or succinic anhydrides may also be used.

[0068] Advantageously, the lubricating composition comprises at least one ashless antioxidant additive.

[0069] The additive(s) described above may be used in the lubricating composition according to the invention in a proportion of 0.1 to 2% by weight relative to the total mass of the composition.

[0070] Lubricating compositions according to the present invention may also contain at least one anti-wear and / or extreme pressure additive.

[0071] Anti-wear and extreme pressure additives protect surfaces subjected to friction by forming a protective film that adsorbs onto the surface.

[0072] There are a wide variety of anti-wear additives. Preferably, the anti-wear additive is selected from metal alkylthiophosphates, more specifically zinc alkylthiophosphates, more specifically zinc dialkyldithiophosphates or phosphorus-sulfur additives such as ZnDTP. Preferred compounds have the formula Zn((SP(S)(OQ 2 )(OQ 3 ))2, wherein Q 2 and Q 3 are the same or different and independently represent an alkyl group, preferentially an alkyl group containing 1 to 18 carbon atoms.

[0073] Amine phosphates are also anti-wear additives that can be used in the lubricating compositions of the present invention. However, the phosphorus provided by such additives can produce ash and act as a poison in automotive catalyst systems. This effect can be minimized by partially replacing the amine phosphates with non-phosphorus-contributing additives, such as polysulfides, especially sulfur olefins.

[0074] The lubricating composition may comprise from 0.01 to 6% by weight, preferentially from 0.05 to 4% by weight, more preferentially or from 0.1 to 2% by weight of anti-wear and extreme pressure additives relative to the total weight of the composition.

[0075] The lubricating composition according to the present invention may further comprise an antifoaming agent.

[0076] The antifoaming agent may be selected from silicones.

[0077] The lubricating composition may comprise from 0.01 to 2% by weight or from 0.01 to 5% by weight, preferentially from 0.1 to 1.5% by weight or from 0.1 to 2% by weight of antifoaming agent relative to the total weight of the composition.

[0078] Lubricating compositions according to the present invention may further comprise at least one friction modifying additive.

[0079] The friction modifying additive may be selected from compounds that provide metal elements and ashless compounds. The metal modifying compounds include complexes of transition metals such as Mo, Sb, Sn, Fe, Cu, and Zn, whose ligands may be hydrocarbon compounds containing oxygen, nitrogen, sulfur, or phosphorus atoms. The ashless friction modifying additives are generally organic in origin and may be selected from fatty acid and polyol monoesters, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, fatty epoxide borates, fatty amine acids, or fatty acid glycerol esters. According to the present invention, the fatty compound contains at least one hydrocarbon moiety containing 10 to 24 carbon atoms.

[0080] The lubricating composition may comprise from 0.01 to 2% or from 0.01 to 5% by weight, preferentially from 0.1 to 1.5% or from 0.1 to 2% by weight, of friction modifying additive relative to the total weight of the composition.

[0081] The lubricating composition according to the invention may comprise at least one additive making it possible to improve the viscosity index of the lubricating composition ("viscosity index improver" in English).

[0082] "Viscosity index improver" as defined by the present invention refers to compounds that help provide good cold resistance and minimal viscosity at high temperatures to a lubricating composition.

[0083] Examples of viscosity index improving polymers include polymeric esters; hydrogenated or non-hydrogenated homopolymers or copolymers of styrene, butadiene and isoprene; homopolymers or copolymers of olefins such as ethylene or propylene; polyacrylates and polymethacrylates (PMAs).

[0084] Lubricating compositions according to the present invention typically contain from 0.1 wt % to 15 wt % of a viscosity index improver, based on the total weight of the lubricating composition.

[0085] The lubricating composition according to the present invention may also comprise at least one detergent additive.

[0086] Detergent additives generally reduce the formation of deposits on the surfaces of metal parts by dissolving oxidation and combustion by-products.

[0087] Detergent additives that can be used in lubricating compositions are generally known to those skilled in the art. Detergent additives may be anionic compounds containing an oleophilic hydrocarbon portion and a hydrophilic head. The associated cation may be a metal cation of an alkali metal or alkaline earth metal.

[0088] The detergent additives are preferably selected from alkali metal or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates and phenates. The alkali and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

[0089] Such metal salts generally contain stoichiometric or excess amounts of metal, i.e., concentrations greater than the stoichiometric amount. Overbased detergents are similar, in that the excess metal that gives the detergent additive its overbased character is generally in the form of an oil-insoluble metal salt, such as carbonate, hydroxide, oxalate, acetate, glutamate, preferentially carbonate.

[0090] The lubricating compositions used in accordance with the present invention may contain, for example, 2 to 4% by weight of detergent additive, based on the total weight of the composition.

[0091] The lubricating compositions used in accordance with the present invention may further comprise at least one pour point depressant additive.

[0092] By retarding the formation of paraffin crystals, pour point depressant additives generally improve the behavior of the composition under low temperature conditions. Examples of pour point depressant additives include alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes, and alkyl polystyrenes.

[0093] Lubricating compositions used in accordance with the present invention may, for example, contain from 0.05 to 2 wt. % of the pour point depressant additive, based on the total weight of the composition.

[0094] The lubricating compositions used in accordance with the present invention may also include at least one dispersant.

[0095] The dispersant may be selected from Mannich bases, succinimides and their derivatives. The lubricating composition used in accordance with the present invention may, for example, contain 0.2 to 10% by weight of dispersant relative to the total weight of the composition. DETAILED DESCRIPTION OF THE INVENTION

[0096] According to a particular embodiment, the lubricating composition used according to the invention comprises or is formed by (i) at least one monoester according to the invention and (ii) at least one additive selected from antioxidants, antifoam agents, pour point depressants, anticorrosion agents, antiwear and / or extreme pressure additives, friction modifiers, detergents, dispersants, and mixtures thereof, preferably from antioxidants, pour point depressants, antifoam agents, anticorrosion agents, and mixtures thereof.

[0097] Advantageously, the lubricating composition used according to the invention comprises (i) a monoester according to the invention and (ii) at least one antioxidant additive.

[0098] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 50% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 60 to 90% by weight, of one or more base oils different from 1-methylheptyl laurate, optionally 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. % of one or more additives selected from friction modifying additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoam agents, thickeners, corrosion inhibitors, copper passivators and mixtures thereof; and The content is expressed relative to the total weight of the composition.

[0099] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 45% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 55 to 90% by weight, of one or more base oils different from 1-methylheptyl laurate, 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. % of one or more additives selected from friction modifying additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoam agents, thickeners, corrosion inhibitors, copper passivators and mixtures thereof and The content is expressed relative to the total weight of the composition.

[0100] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 50% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 55 to 90% by weight, of one or more base oils different from esters, optionally 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. % of one or more additives selected from friction modifying additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoam agents, thickeners, corrosion inhibitors, copper passivators and mixtures thereof; and The content is expressed relative to the total weight of the composition.

[0101] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 45% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 55 to 90% by weight, of one or more base oils different from esters, 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. % of one or more additives selected from friction modifying additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoam agents, thickeners, corrosion inhibitors, copper passivators and mixtures thereof and The content is expressed relative to the total weight of the composition.

[0102] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 45% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 55 to 90% by weight, of one or more base oils different from esters, 0.01 to 20% by weight, preferably 0.1 to 15% by weight, otherwise preferably 0.5 to 10% by weight of one or more additives selected from antioxidants, pour point depressants, antifoam agents, anticorrosive agents, and mixtures thereof and The content is expressed relative to the total weight of the composition.

[0103] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 50% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 55 to 90% by weight, of one or more mineral or synthetic base oils selected from Group I oils, Group II oils, Group III oils and Group IV oils, and mixtures thereof; optionally 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. % of one or more additives selected from friction modifying additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoam agents, thickeners, corrosion inhibitors, copper passivators and mixtures thereof; and The content is expressed relative to the total weight of the composition.

[0104] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 45% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 55 to 90% by weight, of one or more mineral or synthetic base oils selected from Group I oils, Group II oils, Group III oils and Group IV oils, and mixtures thereof; 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. % of one or more additives selected from friction modifying additives, antiwear additives, extreme pressure additives, detergents, antioxidants, viscosity index (VI) improvers, pour point depressant additives (PPD), dispersants, antifoam agents, thickeners, corrosion inhibitors, copper passivators and mixtures thereof and The content is expressed relative to the total weight of the composition.

[0105] According to one particular embodiment, the lubricating composition used in accordance with the present invention comprises: 5 to 45% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate, from 50 to 95% by weight, preferably from 55 to 90% by weight, of one or more mineral or synthetic base oils selected from Group I oils, Group II oils, Group III oils and Group IV oils, and mixtures thereof; 0.01 to 20% by weight, preferably 0.1 to 15% by weight, otherwise preferably 0.5 to 10% by weight of one or more additives selected from antioxidants, pour point depressants, antifoam agents, anticorrosive agents, and mixtures thereof and The content is expressed relative to the total weight of the composition.

[0106] The lubricating compositions used according to the invention advantageously have a viscosity of 1 to 6 mm, measured at 100° C. according to standard ASTM D445. 2 / s, preferably 1 to 4 mm 2 / s range of kinematic viscosity.

[0107] The lubricating compositions used according to the invention advantageously have a viscosity of between 2 and 20 mm, measured at 40° C. according to standard ASTM D445. 2 / s, preferably 3 to 10 mm 2 / s range of kinematic viscosity. Purpose

[0108] As noted above, the lubricating composition according to the present invention can be used as a lubricating fluid for a transmission.

[0109] More specifically, the lubricating compositions defined in the present invention help improve the efficiency performance of transmissions.

[0110] 1-Methylheptyl laurate, when incorporated into lubricating compositions used to lubricate transmissions, improves transmission performance.

[0111] 1-methylheptyl laurate also improves the fuel economy, or "fuel saving," properties of lubricating compositions containing the 1-methylheptyl laurate. In fact, 1-methylheptyl laurate helps to reduce the traction coefficient of lubricating compositions containing the 1-methylheptyl laurate.

[0112] The transmission may be a transmission for an internal combustion vehicle engine and / or a transmission for an electric or hybrid vehicle propulsion system.

[0113] The transmission of the propulsion system of an electric or hybrid vehicle more particularly includes a reduction gear, and the monoester according to the invention therefore most particularly serves to improve the efficiency of the reduction gear in the propulsion system of an electric or hybrid vehicle.

[0114] As shown diagrammatically in Figure 1, the propulsion system of an electric or hybrid vehicle comprises, among other components, an electric motor (1), an electric battery (2) and a transmission, more particularly a reduction gear (3).

[0115] An electric motor typically comprises electronic output components (11) connected to a stator (13) and a rotor (14). The stator comprises coils, more specifically copper coils, which are alternately supplied with current. In this way, a rotating magnetic field is generated. The rotor itself comprises coils or permanent magnets or other magnetic material, which are rotated by the rotating magnetic field.

[0116] The electronic power components (11), stator (13) and rotor (14) of the propulsion system (1) are components with complex structures that generate a large amount of heat during motor operation.

[0117] The bearings (12) are generally integrated between the stator (13) and the rotor (14). The transmission, and more specifically the reduction gear (3), serves to reduce the rotational speed at the output of the electric motor and adapt the speed transmitted to the wheels, making it possible at the same time to control the speed of the vehicle.

[0118] Advantageously, the lubricating compositions defined in the present invention can be used to improve the efficiency of transmissions, more particularly for internal combustion engine vehicle engines and electric or hybrid vehicle propulsion systems, and more particularly for improving the efficiency of reduction gears in electric or hybrid vehicle propulsion systems.

[0119] According to another aspect thereof, the present invention further relates to a method for lubricating at least one mechanical part of a transmission member of a motor vehicle, in particular a light or heavy vehicle, such as a gearbox, an axle, preferably a manual gearbox and a heavy vehicle axle, or a reduction gear of an electric or hybrid vehicle, said method comprising at least one step of contacting said mechanical part with at least one lubricating composition according to the present invention.

[0120] The present invention further relates to the use of the monoesters according to the invention as defined herein above for reducing the traction coefficient in lubricating compositions for the transmissions of motor vehicles, more particularly in lubricants for gearboxes and / or axles, in particular in lubricants for the axles of heavy vehicles, or in reduction gears of electric or hybrid vehicles.

[0121] As mentioned above, the lubricating compositions according to the invention also have excellent properties with respect to reducing fuel consumption ("fuel saving" properties).

[0122] Advantageously, therefore, the lubricating composition according to the present invention has a low traction coefficient.

[0123] The lubricating compositions defined in the present invention may also be used to cool electric motors in electric or hybrid vehicles, more particularly to cool the power electronics and / or rotor and / or stator of the electric motor and / or motor reduction gear.

[0124] The present invention will now be illustrated by the following examples, which are given by way of illustration and not limitation of the present invention. [Example]

[0125] The properties of the monoester (E1) of the present invention, the lauric acid ester of 2-octanol, were compared with another monoester, the lauric acid ester of 2-ethylhexanol (E2).

[0126] 2-Ethylhexanol is not of biogenic origin, but the 2-octanol used in the examples is of biogenic origin.

[0127] The kinematic viscosity at 40°C (KV40) and at 100°C (KV100) were determined according to standard ASTM D445.

[0128] The mini pour point (mini PP) is measured according to standard ASTM D7346.

[0129] Viscosity index (VI) is measured according to ASTM D2270.

[0130] Tribological properties can be evaluated by testing on a tribometer of the MTM type (also known as ball-plane mini-traction machine) from the brand PC equipment. This test serves to evaluate the performance of a lubricant in terms of friction under mixed / limited conditions depending on the applied load, pressure or speed conditions.

[0131] The traction coefficient of the tested lubricating composition is determined at 40°C, 100°C and 140°C using a hardened steel ball about 2 cm in diameter, for example 1.905 cm in diameter, on a hardened steel flat surface.

[0132] Such devices serve to move a steel ball and a steel flat surface relative to one another to determine the coefficient of friction of a given lubricant composition while varying various characteristics such as speed, load, and temperature. The hardened steel surface has an AISI 52100 standard with a mirror finish, and the ball also has an AISI 52100 standard and is made from hardened steel. The applied load is 25N, and the rotation speed varies from 20mm / s to 2500mm / s (SRR (slide-roll ratio = 5%)).

[0133] Approximately 50 ml of the lubricating composition being tested was added to the device. The ball was engaged face-to-face with a flat surface, and the ball and flat surface were independently manipulated to form a mixed roll / slide contact.

[0134] The traction coefficient is measured and recorded by a force sensor.

[0135] Table 2 summarizes the results of the tribological property measurements at 40°C (40°C SRR 5%), 100°C (100°C SRR 5%), and 140°C (140°C SRR 5%).

[0136] [Table 2]

[0137] As shown by the results in the table, the monoesters according to the invention have better traction coefficients, i.e., lower traction coefficients, than the comparative monoesters of the prior art. Lower traction coefficients allow for better benefits in terms of fuel economy (fuel savings) for internal combustion engines and better benefits in terms of battery autonomy for electric or hybrid vehicles.

Claims

1. Use of a composition comprising 1-methylheptyl laurate as a lubricating composition for transmissions.

2. 10. Use of the composition according to claim 1 for transmissions in internal combustion engines and / or reduction gears in electric motors.

3. 3. Use of a composition according to claim 1 or 2 to improve the efficiency of a transmission.

4. 4. Use of a composition according to any one of claims 1 to 3 to reduce fuel consumption of a vehicle having transmission components, particularly gearboxes and / or axles, lubricated with said lubricating composition.

5. 4. Use of a composition according to any one of claims 1 to 3 to improve the efficiency performance of reduction gears in electric motors.

6. 10. Use of a composition according to any one of claims 1 to 3 or claim 5 for increasing the autonomy of the battery of an electric or hybrid vehicle.

7. 7. Use of a composition according to any one of claims 1 to 6, wherein the lubricating composition comprises 5 to 50 wt. % of 1-methylheptyl laurate, preferably 10 to 40 wt. % of 1-methylheptyl laurate, based on the total weight of the lubricating composition.

8. based on the total weight of the lubricating composition 5 to 50% by weight, preferably 10 to 40% by weight, of 1-methylheptyl laurate; 50 to 95% by weight, preferably 60 to 90% by weight, of one or more base oils different from 1-methylheptyl laurate; 8. Use of the composition according to any one of claims 1 to 7, comprising:

9. The lubricating composition has a viscosity of 1 to 6 mm at 100°C. ２ / s range, preferably 1 to 4 mm ２ 9. Use of a composition according to any one of claims 1 to 8, having a kinematic viscosity in the range of 1 / s.

10. 10. Use of a composition according to any one of claims 1 to 9, wherein the 1-methylheptyl laurate has a carbon content of biological origin of at least 90% by weight relative to the total weight of carbon atoms.

11. 11. Use of a composition according to any one of claims 1 to 10, characterized in that the lubricating composition comprises, in addition to 1-methylheptyl laurate, at least one additive selected from antioxidants, additives for improving the viscosity index, pour point depressants, antifoam agents, anticorrosion agents, antiwear and / or extreme pressure additives, friction modifiers, detergents, dispersants and mixtures thereof, more particularly from antioxidants, pour point depressants, antifoam agents and anticorrosion agents.

12. 12. Use of the composition according to claim 11, wherein the additive(s) represent 0.01 to 20 wt. %, preferably 0.1 to 15 wt. %, otherwise preferably 0.5 to 10 wt. %, relative to the total weight of the lubricating composition.

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