JP2022538640A - Use of sterically hindered aromatic amines or phenolic compounds as anticorrosion additives in lubricant compositions for electric or hybrid vehicle propulsion systems - Google Patents

Abstract

The present invention relates to the use of at least one compound having at least one sterically hindered amine or phenolic function as an anticorrosion additive in a lubricant composition for propulsion systems of electric or hybrid vehicles, said The use wherein the lubricant composition comprises one or more amino and/or sulfur antiwear additives. The present invention also provides at least one sterically hindered compound as one or more anti-corrosion additives for lubricating propulsion systems of electric or hybrid vehicles, in particular for lubricating electric motors and power electronics of electric or hybrid vehicles. The present invention relates to the use of a lubricant composition comprising one or more compounds with type amine or phenol functional groups and further comprising one or more amine-based and/or sulfur-based antiwear additives.

Description

The present invention relates to the field of lubricant compositions for propulsion systems of electric or hybrid vehicles. More particularly, the present invention relates to at least one steric compound for improving the anticorrosion properties of lubricant compositions incorporating one or more amine-based and/or sulfur-based antiwear additives. It relates to the use of compounds with sterically hindered amine or phenol functional groups.

Changing international standards not only for reducing CO ₂ emissions, but also for reducing energy consumption, lead motor vehicle manufacturers to propose alternative solutions to combustion engines.

One solution identified by motor vehicle manufacturers consists in replacing the combustion engine with an electric motor. Research aimed at reducing CO ₂ emissions has therefore led a certain number of motor vehicle companies to develop electric vehicles.

For the purposes of the present invention, the term "electric vehicle" refers to a vehicle having an electric motor as sole means of propulsion, in contrast to a hybrid vehicle having a combustion engine and an electric motor as a combined means of propulsion.

For the purposes of the present invention, the term "propulsion system" refers to a system containing the mechanical components necessary to propel an electric vehicle. Thus, the propulsion system more particularly includes a rotor-stator assembly of electric motors or power electronics (dedicated to speed control), a transmission and a battery.

Generally, in electric or hybrid vehicles, lubricants, also known as "lubricants", primarily for the purpose of reducing frictional forces between various parts of the vehicle's propulsion system, particularly between metal parts in the motor during motion. composition should be used. These lubricant compositions are also particularly effective in preventing premature wear of their surfaces or even damage to these parts.

To do this, the lubricant composition is generally formulated with a number of additives aimed at obtaining additional performance, as well as friction modifying additives, which enhance the lubricant performance of the base oil. It is conventionally composed of one or more base oils that are combined.

In particular, "anti-wear" additives are considered to reduce wear on the mechanical parts of the motor and thus prevent deterioration of the motor's durability.

A wide variety of anti-wear additives exist, among others such as dimercaptothiadiazoles, polysulfides, sulfur-based olefins, amine phosphates or phospho-sulfur additives such as metal alkylthiophosphates, especially zinc alkylthiophosphates, and more. Specific examples include zinc dialkyldithiophosphate and ZnDTP.

Among these antiwear additives, amine- and/or sulfur-based antiwear agents such as dimercaptothiadiazoles, zinc dithiophosphates or polysulfides are particularly preferred.

Unfortunately, these amine-based and/or sulfur-based antiwear additives, such as dimercaptothiadiazole, have the drawback of being corrosive. Corrosion problems are particularly critical in electric propulsion systems. In particular, corrosion can affect not only the stator and rotor windings, sensors in propulsion systems, solenoid valves in hydraulic systems, but also the rotor-to-stator connections of electric motors, which are generally copper-based and therefore particularly prone to corrosion. This can lead to the risk of deterioration of rolling bearings or propulsion system seals or varnish.

The present invention is specifically directed to overcoming this drawback.

Furthermore, to allow cooling of the propulsion system of an electric or hybrid vehicle, it is imperative that the lubricant be insulated to avoid failure of electrical components. In particular, conductive lubricants can lead to the risk of electrical leakage in the stator and rotor windings, which reduces the efficiency of the propulsion system, possible overheating of electrical components and even points of failure of the system. occur. Therefore, in the context of using lubricants in electric or hybrid vehicle powertrain systems, it is important that lubricants have good "electrical" properties in addition to non-corrosive properties.

WO 2006/064138 Pamphlet International Publication No. 2011/073960 Pamphlet

The present invention is specifically directed to obtaining such properties.

More precisely, the present invention is directed to electric or hybrid vehicle propulsion systems and as an anti-corrosion additive in a lubricant composition comprising one or more amine-based and/or sulfur-based anti-wear additives. of at least one compound having at least one sterically hindered amine or phenolic function.

Compounds with at least one sterically hindered amine or phenol functionality, particularly compounds with only one sterically hindered amine or phenol functionality, are referred to in the remainder of the text as "Hindered amine or phenol functionality. are called "compounds having

Compounds with sterically hindered amine or phenol functional groups, such as hindered aromatic amines or phenols, especially alkylphenols, are useful as antioxidants, e.g. in engine lubricants, as described e.g. Functionality has already been described. These antioxidants generally make it possible to retard the deterioration of the usable composition. This deterioration can be reflected, inter alia, in the formation of deposits, the presence of precipitates, or an increase in viscosity of the composition. Antioxidants are capable of scavenging free radicals formed during use of the lubricant, thus making it possible to interrupt chain reactions that tend to lead to acid buildup.

However, to the best of the inventors' knowledge, in the context of using lubricants for electric or hybrid vehicle propulsion systems to overcome the corrosive effects brought about by the use of amine-based and/or sulfur-based antiwear additives. , the use of these compounds as anticorrosion additives has never been proposed.

Surprisingly, as illustrated in the examples below, the inventors have found that such additives with sterically hindered amine or phenol functional groups, for example of the diarylamine type, are amine-based and/or sulfur-based can effectively reduce the corrosion effects induced by antiwear additives.

Thus, one or more amine-based and/or sulfur-based antiwear additives are added, especially by the addition of at least one compound having a sterically hindered amine or phenolic function, of the aromatic amine or alkylphenol type. The anti-corrosion properties of a lubricant composition comprising can be advantageously improved.

For the purposes of the present invention, the term "anti-corrosion additive" refers to additives for preventing or reducing corrosion of metal parts. Accordingly, the anti-corrosion additive used in the composition makes it possible to improve the "corrosion resistance" properties of said composition.

The use of one or more compounds having sterically hindered amine or phenol functional groups according to the present invention together with one or more amine-based and/or sulfur-based antiwear additives results in good wear resistance. A lubricant composition is advantageously obtained which simultaneously possesses wear performance while simultaneously overcoming the already mentioned corrosion problems. The compositions according to the invention thus have simultaneously good anti-wear and anti-corrosion properties.

The corrosive (or erosive) power of a compound is measured as a function of the duration of immersion of a copper wire of given diameter in a composition containing said test compound in a non-corrosive medium, such as one or more base oils. can be evaluated by a test that investigates variations in the electrical resistance of this wire. This change in electrical resistance directly correlates with the change in diameter of the test wire. Therefore, in the context of the present invention, a compound is defined as " called "non-corrosive".

The dielectric properties of lubricants are expressed in particular by electrical resistance and dielectric loss (tan δ) and can be measured according to standard IEC 60247.

Electrical resistance describes the ability of a material to resist the flow of electric current. Electrical resistance is expressed in ohm-meters (Ω.m). The resistance must be low enough to prevent electrical conduction.

The electric dissipation factor or loss angle tangent can also be used to measure lubricant properties. The loss angle δ is the complementary angle of the phase shift between the applied voltage and alternating current. This factor reflects the Joule effect energy loss. Heating is therefore directly related to the δ value. Transmission fluids typically have single order tan delta values at room temperature. A good insulation lubricant must maintain low tan delta levels.

Advantageously, the sterically hindered amines according to the invention or compounds with a phenolic function used according to the invention are aromatic amines, especially diarylamine compounds, more particularly diphenylamine compounds; sterically hindered phenols, especially alkylphenols; selected from mixtures thereof;

According to a preferred embodiment, the compound with a sterically hindered amine or phenolic function has 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms, especially in at least one of the para positions to the amine function. substituted diphenylamines substituted with at least one alkyl or alkenyl group, including

As an example, the compound can be p,p'-butyloctyldiphenylamine.

According to another preferred embodiment, in the compound with sterically hindered amine or phenol functionality, at least one carbon adjacent to the carbon with alcohol functionality has an optionally substituted C ₁ -C ₁₀ alkyl group and a compound containing a phenol group substituted with at least one group selected from hydroxyl functional groups.

By way of example, said compound can be octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate or 2,6-di-tert-butylphenol.

Accordingly, the introduction of one or more compounds having sterically hindered amine or phenol functional groups according to the present invention into a lubricant composition intended for the propulsion system of an electric or hybrid vehicle is advantageous if the composition It allows the use of amine-based and/or sulfur-based antiwear additives such as dimercaptothiadiazoles in, but without detrimental corrosive effects.

The amine-based and/or sulfur-based antiwear additives used in the lubricant composition according to the present invention are detailed in more detail in the text below. They are preferably selected from amine-based and sulfur-based antiwear additives. They may preferably be thia(di)azole compounds, especially dimercaptothiadiazole derivatives.

Furthermore, compositions suitable for use in the present invention have the advantage of being easy to formulate. In addition to good wear and corrosion resistance performance, it has good stability, especially with respect to oxidation, and also good properties in terms of electrical insulation.

The invention also relates to lubricating propulsion systems of electric or hybrid vehicles, in particular electric motors and power electronics of electric or hybrid vehicles.
- as anticorrosion additives, one or more compounds containing at least one sterically hindered amine or phenolic function as defined in the present invention;
- relates to the use of lubricant compositions comprising one or more amine-based and/or sulfur-based antiwear additives as defined in the present invention.

The subject of the present invention is also a method for lubricating a propulsion system of an electric or hybrid vehicle, wherein at least one mechanical part of said system comprises, as an anti-corrosion additive, a sterically hindered as defined in the present invention. Placed in contact with a lubricant composition comprising at least one compound having an amine or phenolic functionality and at least one amine-based and/or sulfur-based antiwear additive as defined in the present invention A method comprising at least one step.

Advantageously, the lubricant composition according to the invention is applied to the electric motor itself, in particular the rolling bearings located between the rotor and the stator of the electric motor and/or the transmission, in particular the speed reducer, of an electric or hybrid vehicle. Used to lubricate the machine.

Other features, variants and advantages of the use of sterically hindered amines or compounds with phenol functional groups as anticorrosion additives according to the present invention can be found by reading this description and the following examples given as non-limiting examples of the invention. appears more clearly in

In the text that follows, the expressions "between... It is intended to be meant to include boundaries unless otherwise stated.

1 is a schematic diagram representing a propulsion system for an electric or hybrid vehicle; FIG.

Anticorrosion Additives with Sterically Hindered Amine or Phenolic Functionality As already mentioned, one or more amine-based and/or sulfur-based antiwear agents in lubricant compositions for electric or hybrid vehicle powertrain systems. The additive used as anticorrosion agent according to the invention together with the additive is a compound having at least one sterically hindered amine or phenolic function.

As already mentioned, compounds with sterically hindered amine or phenol functional groups, more particularly aromatic amines and hindered phenols, etc., are known for their antioxidant action to those skilled in the art of lubricants. These compounds are capable of acting as radical inhibitors.

The term "sterically hindered functional group" means that the functional group is hindered by a steric effect or constraint. The effect of this hindrance is to make the amine or phenol functional group significantly less nucleophilic than the unhindered amine or phenol functional group, thus preventing nucleophilic addition reactions.

Such compounds are described, for example, in patent applications WO 2006/064 138, WO 2011/073 960 and others.

However, as already indicated, in order to reduce or even inhibit the corrosive effects induced by the use of one or more amine-based and/or sulfur-based anti-wear additives, electric or hybrid vehicle powertrain Such compounds have never been proposed as anti-corrosion additives in lubricants for systems.

Compounds with hindered amine functionality may more particularly be selected from aromatic amines, especially as defined in the text hereinafter.

The compound with a hindered phenolic function is preferably selected from sterically hindered phenols, especially alkylphenols, especially as defined in the text hereinafter.

Thus, according to a particular embodiment, said compound with hindered amine or phenol functionality is selected from aromatic amines, sterically hindered phenols, and mixtures thereof.

In particular, aromatic amine type compounds have the formula:

(wherein R ₃ and R ₄ are independently of each other a hydrogen atom, a C _1-20 , preferably a C _4-16 aliphatic group, or an aromatic or heteroaromatic, monocyclic or condensed polycyclic represents a formula, a substituted or unsubstituted group; R ₅ is an aromatic or heteroaromatic, monocyclic or fused polycyclic group, which is unsubstituted or has at least one C _1-20 alkyl substituted have a group; or
R ₃ and R ₅ together form an aromatic or heteroaromatic, monocyclic or fused polycyclic group)
can have

Aromatic amines are more particularly substituted or unsubstituted diphenylamine, substituted or unsubstituted phenylnaphthylamine, substituted or unsubstituted phenothiazine, substituted or unsubstituted imidodibenzyl, substituted or unsubstituted N,N'-diphenyl(phenylenediamine) , and mixtures thereof.

According to a particularly preferred embodiment, the compound with hindered amine functionality is selected from secondary amines in which the nitrogen atom is linked to at least one aryl group, preferably at least one phenyl group.

Preferably, the compound with a hindered amine function is selected from diarylamine compounds, more particularly diphenylamine compounds, in particular wherein at least one of the aryl groups is phenyl.

Thus, according to certain embodiments, compounds with hindered amine functionality preferably have the formula:

(Wherein, R ₆ and R ₇ are, independently of each other,
- a hydrocarbon selected from hydrocarbon-based groups, in particular alkyl or alkenyl groups containing 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms, preferably para to the amine function; a phenyl group, optionally substituted by a base group; and
- a hydrocarbon selected from hydrocarbon-based groups, in particular alkyl or alkenyl groups containing 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms, preferably para to the amine function; selected from naphthyl groups, optionally substituted on the base group)
is an aromatic amine type compound selected from diarylamines corresponding to

Advantageously, the compounds with hindered amine or phenol functional groups are preferably substituted with at least one alkyl or alkenyl group containing from 1 to 12 carbon atoms, preferably from 3 to 10 carbon atoms, In particular it is selected from diphenylamine compounds substituted in at least one of the para-positions to the amine function.

In other words, the compound having a hindered amine function advantageously has the following formula (I):

(wherein R ₁ and R ₂ are independently of each other a hydrogen atom; a linear or branched alkyl or alkenyl group containing 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms; , preferably selected from alkyl groups)
can be a compound of

According to _a particular embodiment, the compounds with hindered amine functionality _are direct A compound of formula (I) as described above, which is a linear or branched alkyl or alkenyl group, preferably an alkyl group.

Preferably, said compounds are linear or branched alkyl or alkenyl groups in which R ₁ and R ₂ independently of each other contain from 1 to 12 carbon atoms, preferably from 3 to 10 carbon atoms. are compounds of formula (I) as described above, preferably selected from alkyl groups.

Preferably R ₁ and R ₂ are para to the amine function.

In other words, the compound with hindered amine functionality is advantageously of formula (I'):

(wherein R ₁ and R ₂ are as previously defined)
can be a compound of

Advantageously, R ₁ and R ₂ , which may be identical or different, represent linear or branched C ₁ -C ₁₂ , preferably C ₃ -C ₁₀ alkyl groups, for example linear are selected from straight or branched octyl and butyl groups;

Compounds with hindered amine functionality may be purchased or prepared according to synthetic methods known to those skilled in the art.

As an example, p,p'-butyloctyldiphenylamine may be mentioned.

Compounds with hindered amine or phenol functional groups can also be sterically hindered phenol type compounds.

A sterically hindered phenol-type compound is preferably a phenolic group in which at least one carbon atom, other than the hydroxyl-functional carbon atom that forms part of the phenyl group, is a hydroxyl group, a linear A compound containing a phenolic group with a branched or branched C _1-10 alkyl, dialkylaminoalkyl or _styryl group

Preferably, the sterically hindered phenol is a phenol in which at least one carbon adjacent to the carbon bearing the alcohol functional group is substituted with at least one group selected from C ₁ -C ₁₀ alkyl groups and hydroxyl functional groups. is selected from compounds containing groups.

In other words, the compound with hindered phenolic functionality has the following formula (II):

(In the formula,
at least one of R ¹ and R ² represents a C ₁ -C ₁₀ alkyl group, preferably a C ₁ -C ₆ alkyl group, preferably a C ₄ alkyl group, such as tert-butyl; or a hydroxyl group;
Carbon atoms of the benzene ring other than those bearing groups R ¹ , R ² and OH may be substituted)
can be a sterically hindered phenol of

In particular, compounds with hindered phenol functional groups have the following formula (II'):

(In the formula,
at least one of R ¹ and R ² represents a C ₁ -C ₁₀ alkyl group, preferably a C ₁ -C ₆ alkyl group, preferably a C ₄ alkyl group, such as tert-butyl; or a hydroxyl group;
n is an integer from 0 to 3;
R is, independently of each other, one or more optionally substituted with one or more C ₂ -C ₁₀ alkoxycarbonyl groups such as octyloxycarbonyl groups and/or with one or more alkyl groups. and a hydroxyl group), optionally substituted with _{an aryl} group of
can be a compound of

Examples of sterically hindered phenol type compounds include 2,6-di-t-butyl-4-methylphenol (BHT), t-butylhydroquinone (TBHQ), 2,6- and 2, alone or in mixtures. ,4-di-t-butylphenol, 2,4-dimethyl-6-t-butylphenol, pyrogallol and octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate may be mentioned.

Preferably, the sterically hindered phenol-type compound has at least one, preferably both ortho positions to the hydroxyl function, preferably C ₁ -C ₁₀ sterically hindered alkyl groups, especially C ₁ -C ₆ , especially selected from "alkylphenol" compounds containing phenolic groups with _C4 alkyl groups, preferably tert-butyl.

In particular, sterically hindered phenol type compounds are characterized in that at least one of R ¹ and R ² or even both groups R ¹ and R ² are C ₁ -C ₁₀ alkyl groups, preferably C ₁ -C It may be a compound of formula (II) above, especially formula (II') above, selected from ₆ alkyl groups, preferably _C4 alkyl groups, preferably tert-butyl.

Compounds with hindered phenol functionality may be purchased or prepared according to synthetic methods known to those skilled in the art.

As examples of preferred compounds of the sterically hindered phenol type, octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate or 2,6-di-tert-butylphenol may be mentioned. An even more preferred example of a sterically hindered phenol type compound that may be mentioned is octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate.

According to a preferred embodiment, the sterically hindered aromatic amine or phenol type compound is p,p'-butyloctyldiphenylamine, octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 2,6- selected from di-tert-butylphenol, and mixtures thereof.

According to an even more preferred embodiment, the sterically hindered aromatic amine or phenol type compound is p,p'-butyloctyldiphenylamine, octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate and its selected from a mixture.

The present invention is not limited to the above hindered aromatic amine or phenol type compounds. In particular, sterically hindered amines known as antioxidants or other compounds with phenolic functionality may be used as anticorrosion additives according to the present invention.

In the context of the present invention the following definitions apply:
- "alkyl": a straight or branched saturated aliphatic group; for example C _x -C _y alkyl represents a straight or branched hydrocarbon-based chain of x to y carbon atoms;
- " _alkenyl ": a straight or branched _unsaturated aliphatic group; show;
- "alkoxy": radical -O-alkyl, where the alkyl group is as previously defined;
- "aryl": a monocyclic or polycyclic aromatic group, especially containing from 5 to 10 carbon atoms. Examples of aryl groups that may be mentioned include phenyl, tolyl and naphthyl groups.

Advantageously, said compound with a sterically hindered amine or phenolic function used according to the invention is
- aromatic amines, especially _{diarylaromatic} amines, as already mentioned, preferably para to the amine function, preferably substituted by at least _one C1-C12 alkyl group, and more Specifically diphenylamine;
- in particular a sterically hindered phenol as already defined, preferably at least one carbon adjacent to the carbon bearing the alcohol function is at least one C ₁ -C ₁₀ , preferably C ₁ -C ₆ , especially C compounds containing a phenolic group substituted with ₄ alkyl groups, especially tert-butyl; and
- selected from the mixture;

In the context of the present invention, a compound with a sterically hindered amine or phenol function is a mixture of at least two compounds with a sterically hindered amine or phenol function, such as at least one with a sterically hindered amine function. with at least one compound having a sterically hindered phenolic function.

Compounds with sterically hindered amine or phenol functions, in particular as already defined, are present in the lubricant composition according to the invention in an amount of from 0.01% by weight to 5% by weight, in particular 0.1% by weight, relative to the total weight of the lubricant composition. % to 3% by weight, more particularly from 0.1% to 1% by weight.

Advantageously, the lubricant composition under consideration according to the present invention does not contain anticorrosion additives other than compounds with sterically hindered amine or phenol functional groups. According to a particular embodiment, the lubricant composition used in accordance with the present invention does not comprise triazole-type or succinimide-type anti-corrosion additives.

Lubricant Compositions Amine-Based and/or Sulfur-Based Antiwear Additives As previously indicated, the lubricant compositions under consideration according to the present invention contain one or more amine-based and/or sulfur-based antiwear additives. containing agents.

The term "amine-based and/or sulfur-based antiwear additive" includes additives selected from amine-based antiwear additives, sulfur-based antiwear additives, and amine-based and sulfur-based antiwear additives. say the drug

The term "antiwear additive" means a compound that, when used in lubricant compositions, in particular lubricant compositions for propulsion systems of electric or hybrid vehicles, makes it possible to improve the antiwear properties of the composition. say.

Amine-based and/or sulfur-based antiwear additives are, for example, thia(di)azole type additives, especially dimercaptothiadiazole derivatives; polysulfide additives, especially sulfur-based olefins, amine phosphates, alkylthiophosphates, etc. Phospho-sulphur additives, and mixtures thereof.

Thia(di)azole Additives According to a particularly preferred embodiment, the lubricant composition under consideration according to the invention comprises at least one thia(di)azole antiwear additive.

Thia(di)azole compounds are compounds that contain both a sulfur atom and at least one nitrogen atom in the pentaatomic ring. Benzothiazoles are a specific type of thia(di)azoles. The term "thia(di)azole" includes, in addition to cyclic compounds containing one sulfur atom and one nitrogen atom per five-atom ring, sulfur and two nitrogen atoms in such rings. Thiadiazole containing atoms are also included.

In particular, the thia(di)azole compound may be selected from benzothiazole derivatives, thiazole derivatives and thiadiazole derivatives.

Preferably, the antiwear additive can be a thiadiazole derivative.

Thiadiazoles are heterocyclic compounds containing _two nitrogen atoms, one sulfur atom, _two carbon atoms and _two double bonds of the general formula C2N2SH2, respectively 1,2 1,2,4-thiadiazole; 1,2,5-thiadiazole; the following forms of 1,3,4-thiadiazole:

can exist in

Preferably, the thiadiazole derivative is a dimercaptothiadiazole derivative.

Therefore, according to a particularly preferred embodiment, the lubricant composition according to the invention comprises at least one antiwear additive selected from dimercaptothiazole derivatives.

The term "dimercaptothiadiazole derivative" according to the present invention includes the following four dimercaptothiadiazole molecules, alone or as a mixture: 4,5-dimercapto-1,2,3-thiadiazole, 3,5-dimercapto -1,2,4-thiadiazole, 3,4-dimercapto-1,2,5-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole:

means a compound derived from

Dimercaptothiadiazole derivatives are more particularly 4,5-dimercapto-1,2,3-thiadiazole, 3,5-dimercapto-1,2,4-thiadiazole, 3,4-dimercapto as represented above -1,2,5-thiadiazole or 2,5-dimercapto-1,3,4-thiadiazole-based molecules or mixtures of molecules, wherein at least one of the thiadiazole ring substituents =S, or Furthermore, both substituents =S are the substituents:

(Wherein, * represents a bond with a carbon atom of a 5-membered ring; n represents an integer equal to 1, 2, 3 or 4; R ₁ is a hydrogen atom, 1 to 24, preferably 2 from linear or branched, saturated or unsaturated alkyl groups or aromatic substituents containing up to 18, more preferentially 4 to 16, even more preferentially 8 to 12 carbon atoms selected)
is replaced by

In particular, taking 2,5-dimercapto-1,3,4-thiadiazole as an example, the 2,5-dimercapto-1,3,4-thiadiazole derivatives, alone or as a mixture, have the formula:

(wherein the R ₁ groups are, independently of each other, hydrogen atoms, 1 to 24, preferably 2 to 18, more preferentially 4 to 16, even more preferentially 8 to 12 represents a straight-chain or branched alkyl or alkenyl group containing carbon atoms, or an aromatic substituent, wherein n is independently of each other an integer equal to 1, 2, 3 or 4, n is preferably equal to 1)
is a molecule having

Preferably, R ₁ are independently of each other linear C ₁ -C ₂₄ , preferably C ₂ -C ₁₈ , especially C ₄ -C ₁₆ , more particularly C ₈ -C ₁₂ , preferably C ₁₂ alkyl represents a group.

Dimercaptothiadiazole derivatives for use in the present invention can be purchased, for example, from suppliers Vanderbilt, Rhein Chemie or Afton.

Polysulfide Additives The amine-based and/or sulfur-based antiwear additives used in lubricant compositions according to the present invention may also be selected from polysulfide-type sulfur-based antiwear additives, particularly sulfur-based olefins.

The sulfur-based olefins used in the lubricant composition according to the invention are particularly of the general formula R _a -S _x -R _b , wherein R _a and R _b are 3 to 15 carbon atoms, preferentially is an alkyl group containing 1 to 5 carbon atoms, preferentially 3 carbon atoms, and x is an integer between 2 and 6).

Preferably, the polysulfide additive is selected from dialkyltrisulfides.

Preferably, the antiwear additives present in the compositions used according to the invention are selected from amine-based and sulfur-based antiwear additives, advantageously from thia(di)azole compounds as described above, more It is preferentially selected from dimercaptothiadiazole derivatives.

The lubricant composition under consideration according to the present invention contains from 0.01% to 5%, in particular from 0.1% to 3%, more particularly from 0.1% to 1% by weight, preferably of the thia(di)azole type, More preferentially it may contain amine-based and/or sulfur-based antiwear additives selected from dimercaptothiadiazole derivatives.

It is conceivable to use other antiwear additives known in lubricants, especially for propulsion systems, other than amine-based and/or sulfur-based additives, provided that they contain sterically hindered amines or phenols according to the invention. The proviso is that it does not affect the properties imparted by the combination of said compound with functional groups and said amine-based and/or sulfur-based antiwear additive.

Preferably, the lubricant composition required according to the invention does not contain antiwear additives other than said amine-based and/or sulfur-based antiwear additives used according to the invention.

According to a particularly preferred embodiment, the lubricant composition under consideration according to the invention comprises
- especially,
Aromatic amines, especially diarylaromatic amines, as already described, preferably substituted by at least one C ₁ -C ₁₂ alkyl group, advantageously para to the amine function, and more Specifically diphenylamine;
in particular a sterically hindered phenol as already defined, preferably at least one carbon adjacent to the carbon bearing the alcohol function is at least one C ₁ -C ₁₀ , preferably C ₁ -C ₆ , especially C Compounds containing a phenolic group substituted with ₄ alkyl groups, especially tert-butyl;
and mixtures thereof; and
- preferably in combination with one or more amine-based and sulfur-based antiwear additives, selected in particular from dimercaptothiazole derivatives as defined above.

The composition used according to the invention comprises, in particular, one or more additives with sterically hindered amine or phenolic functions and one or more amine-based and/or sulfur-based additives, as already defined. In addition to antiwear additives, one or more base oils and also other additives conventionally contemplated in lubricant compositions may be included.

Base Oil Accordingly, the lubricant composition under consideration according to the present invention may comprise one or more base oils.

These base oils may be selected from base oils conventionally used in the lubricating art, such as mineral oils, synthetic or natural oils, animal or vegetable oils, or mixtures thereof.

It may also be a mixture of several base oils, for example a mixture of 2, 3 or 4 base oils.

The base oils of the lubricant compositions under consideration according to the invention belong in particular to Groups IV according to the classes defined by the API classification (or their equivalents according to the ATIEL classification) and are listed in Table 1 below. It can be an oil of mineral or synthetic origin as indicated, or mixtures thereof.

Mineral base oils include all refining operations obtained after atmospheric and vacuum distillation of crude oil, such as solvent extraction, deasphalting, solvent deparaffinization, hydrotreating, hydrocracking, hydroisomerization and hydrofinishing. types of base oils are included.

Mixtures of synthetic and mineral oils, which may be biobased, may also be used.

In general, compositions used in accordance with the present invention are prepared, except that they must possess properties that are suitable for use in propulsion systems of electric or hybrid vehicles, particularly with regard to viscosity, viscosity index or resistance to oxidation. There are no restrictions on the use of different base oils for

The base oil of the composition used in accordance with the present invention also includes certain esters of carboxylic acids and alcohols, poly-α-olefins (PAOs), and 2-8 carbon atoms, especially 2-4 carbon atoms. may be selected from synthetic oils such as polyalkylene glycols (PAG) obtained by polymerization or copolymerization of alkylene oxides containing

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

Advantageously, the base oil of the composition used according to the invention is selected from poly-α-olefins (PAO), polyalkylene glycols (PAG) and esters of carboxylic acids and alcohols.

According to an alternative embodiment, the base oil of the composition used according to the invention may be selected from Group II or III base oils.

It is within the ordinary imagination of those skilled in the art to adjust the content of base oil used in compositions suitable for use in the present invention.

A lubricant composition under consideration according to the invention may comprise at least 50% by weight of base oil, in particular 60% to 99% by weight of base oil, relative to its total weight.

Additional Additives Lubricant compositions suitable for use in the present invention also include additives having sterically hindered amine or phenolic functionality as defined in the context of the present invention and amine- and/or sulfur-based resistant additives. Any type of additive suitable for use in lubricants for electric or hybrid vehicle propulsion systems, other than wear additives, may be included.

The nature and amount of additives used will depend on the anti-wear and anti-wear properties imparted by the combination of said compound with sterically hindered amine or phenolic functionality and said amine-based and/or sulfur-based additive used in accordance with the present invention. It is understood that it is selected so as not to affect the properties in terms of corrosion resistance performance.

Such additives known to those skilled in the art of lubricating and/or cooling electric or hybrid vehicle propulsion systems include friction modifiers, detergents, extreme pressure additives, antifoam agents, pour point depressant additives, , dispersants, antioxidants other than compounds with sterically hindered amines or phenolic functional groups according to the invention, pour point depressants, defoamers and mixtures thereof.

Advantageously, compositions suitable for use in the present invention include friction modifiers, detergents, extreme pressure additives, antifoam agents, pour point depressant additives, dispersants, sterically hindered amines according to the present invention. or at least one additional additive selected from antioxidants other than compounds with phenol functional groups and mixtures thereof.

These additives are already commercially available for vehicle engines with performance levels as defined by ACEA (European Automobile Manufacturers Association) and/or API (American Petroleum Institute) individually and/or well known to those skilled in the art. may be introduced in the form of mixtures such as multiple lubricant formulations.

Lubricant compositions suitable for use in the present invention may contain at least one friction modifying additive. Friction modifying additives may be selected from compounds that provide metallic elements and ashless compounds. Among the compounds that provide metallic elements are transition metal complexes such as Mo, Sb, Sn, Fe, Cu or Zn, whose ligands can be hydrocarbon-based compounds containing oxygen, nitrogen, sulfur or phosphorus atoms. be able to. Ashless friction modifying additives are generally of organic origin and are selected from fatty acid monoesters of polyols, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, fatty epoxides of borate, fatty amines or fatty acid esters of glycerol. sell. According to the invention, fatty compounds contain at least one hydrocarbon-based group containing 10 to 24 carbon atoms.

Lubricant compositions suitable for use according to the invention have from 0.01% to 2% by weight, or from 0.01% to 5% by weight, preferentially from 0.1% to 1.5% by weight, relative to the total weight of the composition, Or it may contain from 0.1% to 2% by weight of a friction modifying additive.

The lubricant composition used according to the invention may comprise at least one antioxidant additive different from the compounds with sterically hindered amine or phenolic functions as defined according to the invention.

Antioxidant additives generally make it possible to retard the deterioration of the usable composition. This deterioration can be reflected, inter alia, in the formation of deposits, the presence of precipitates, or an increase in viscosity of the composition.

Antioxidant additives act in particular as free radical inhibitors or hydroperoxide decomposers.

Antioxidant additives different from compounds with sterically hindered amine or phenol functional groups are, for example, copper compounds such as copper thio- or dithio-phosphates, copper salts of carboxylic acids and copper dithiocarbamates, sulfonates, phenates. and acetylacetonate. Copper I and II salts and succinic acid or anhydride salts may also be used.

Lubricant compositions used in accordance with the present invention may contain any type of antioxidant additive known to those skilled in the art.

The lubricant composition used in accordance with the invention may contain from 0.5% to 2% by weight of at least one antioxidant additive, relative to the total weight of the composition.

Advantageously, the lubricant composition used according to the invention does not contain antioxidant additives other than compounds with sterically hindered amine or phenol functional groups as defined according to the invention.

Lubricant compositions suitable for use in the present invention may also include at least one detergent additive.

Detergent additives generally make it possible to reduce the formation of deposits on the surfaces of metal parts by dissolving oxidation and combustion by-products.

Detergent additives that may be used in lubricant compositions used in accordance with the present invention are generally known to those skilled in the art. The detergent additive can be an anionic compound containing a long lipophilic hydrocarbon-based chain and a hydrophilic head. The associated cations can be alkali metal or alkaline earth metal cations.

Detergent additives are preferentially selected from alkali metal or alkaline earth metal salts of carboxylic acids, sulfonates, salicylates and naphthenates and also phenate salts. Alkali metals and alkaline earth metals are preferentially calcium, magnesium, sodium or barium.

These metal salts generally contain stoichiometric or excess, and thus greater than stoichiometric, metals. In that case, they are overbased detergent additives; in which case, the excess metals that provide overbasing to the detergent additive are generally in the form of metal salts that are insoluble in oil, such as carbonates. , hydroxides, oxalates, acetates or glutamates, preferentially carbonates.

Lubricant compositions suitable for use in the present invention may contain, for example, from 2% to 4% by weight of detergent additive relative to the total weight of the composition.

Lubricant compositions used in accordance with the present invention may also contain at least one dispersant.

Dispersants may be selected from Mannich bases, succinimides and derivatives thereof.

Lubricant compositions used in accordance with the present invention may contain, for example, from 0.2% to 10% by weight of dispersant, relative to the total weight of the composition.

According to a particular embodiment, the lubricant composition used in accordance with the present invention does not contain a succinimide type dispersant additive.

Lubricant compositions suitable for use in the present invention may also contain at least one antifoaming agent.

Antifoam agents may be selected from silicones.

Lubricant compositions suitable for use in the present invention have from 0.01% to 2% by weight, or from 0.01% to 5% by weight, preferentially from 0.1% to 1.5% by weight, relative to the total weight of the composition. %, or from 0.1% to 2% by weight of defoamer.

Lubricant compositions suitable for use in the present invention may also contain at least one pour point depressant (PPD).

By slowing the formation of paraffin crystals, pour point depressant additives generally improve the low temperature behavior of compositions. Examples of pour point depressant additives that may be mentioned include polyalkylmethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes and polyalkylstyrenes.

In particular, the lubricant composition used in accordance with the present invention may be free of triazole-type anti-corrosion additives and succinimide-type dispersant additives.

In formulating such lubricant compositions, said compounds having sterically hindered amine or phenolic functionality may be added to the base oil or mixture of base oils to provide amine-based and/or sulfur-based resistant lubricants. Other additional additives, including wear additives, are then added.

Alternatively, said compounds with sterically hindered amine or phenol functional groups are specifically used in one or more base oils, one or more amine-based and/or sulfur-based antiwear additives, and optionally additional may be added to existing conventional lubricant formulations containing additives of

Alternatively, said additives having sterically hindered amine or phenolic functionality according to the present invention may be combined with one or more additional additives such that the additive "pack" thus formed is a base oil. or added to a mixture of base oils.

Advantageously, the lubricant composition used according to the invention has a kinematic viscosity in the range from 1 to 15 mm ² /s, in particular in the range from 3 to 10 mm ² /s, measured at 100° C. according to standard ASTM D445. .

Advantageously, the lubricant composition used according to the invention has a kinematic viscosity in the range from 3 to 80 mm ² /s, in particular from 15 to 70 mm ² /s, measured at 40° C. according to standard ASTM D445.

According to an advantageous embodiment of the invention, the electrical resistance value measured at 90° C. of the lubricant composition used according to the invention is between 5 and 10000 Mohm.m, more preferably between 6 and 5000 Mohm.m. be.

According to an advantageous embodiment of the invention, the dielectric loss value measured at 90° C. of the lubricant composition used according to the invention is between 0.01 and 30, more preferably between 0.02 and 25, more preferentially is between 0.02 and 10.

Advantageously, the lubricant composition used according to the invention has the formula (X)W(Y), where X represents 0 or 5 and Y is in the range 4-20, in particular 4-16 or an integer ranging from 4 to 12) according to the SAEJ300 classification.

According to a particular embodiment, the lubricant composition used according to the invention comprises
- base oils or mixtures of base oils, preferably selected from poly-α-olefins (PAO), polyalkylene glycols (PAG) and esters of carboxylic acids and alcohols;
- especially,
Aromatic amines, especially diarylaromatic amines, as already described, preferably substituted by at least one C ₁ -C ₁₂ alkyl group, advantageously para to the amine function, and more Specifically diphenylamine;
in particular a sterically hindered phenol as already defined, preferably at least one carbon adjacent to the carbon bearing the alcohol function is at least one C ₁ -C ₁₀ , preferably C ₁ -C ₆ , especially C Compounds containing a phenolic group substituted with ₄ alkyl groups, especially tert-butyl;
one or more compounds having sterically hindered amine or phenol functional groups selected from and mixtures thereof;
- more preferentially one or more amine-based and/or sulfur-based antiwear additives selected from compounds of the thia(di)azole type, in particular dimercaptothiazole derivatives as defined above , preferably one or more amine-based and sulfur-based antiwear additives;
- optionally friction modifiers, detergents, extreme pressure additives, defoamers, pour point depressant additives, dispersants, antioxidants other than compounds with sterically hindered amine or phenol functional groups according to the invention and It comprises or even consists of one or more additional additives selected from the mixture.

According to a particular embodiment, the lubricant composition used according to the invention comprises
- 0.01% to 5% by weight, especially 0.1% to 3% by weight, more particularly 0.1% to 1% by weight, especially
- aromatic amines, especially _{diarylaromatic} amines, as already described, which are preferably substituted by at least _one C1-C12 alkyl group, advantageously para to the amine function, and more Specifically diphenylamine;
in particular a sterically hindered phenol as already defined, preferably at least one carbon adjacent to the carbon bearing the alcohol function is at least one C ₁ -C ₁₀ , preferably C ₁ -C ₆ , especially C Compounds containing a phenolic group substituted with ₄ alkyl groups, especially tert-butyl;
and mixtures thereof; and
- 0.01% to 5% by weight, in particular 0.1% to 3% by weight, more particularly 0.1% to 1% by weight, more preferentially from compounds of the thia(di)azole type, especially dimercaptothiazole derivatives selected one or more amine-based and/or sulfur-based antiwear additives, preferably one or more amine-based and sulfur-based antiwear additives;
- 60% to 99.9% by weight of base oils and mixtures thereof, preferably selected from poly-α-olefins (PAO), polyalkylene glycols (PAG) and esters of carboxylic acids and alcohols;
- optionally from 0.01% to 5% by weight of friction modifiers, detergents, extreme pressure additives, antifoam agents, pour point depressant additives, dispersants, sterically hindered amine or phenol functionalities according to the invention comprising or even consisting of one or more additional additives selected from antioxidants and mixtures thereof other than compounds having
Contents are expressed relative to the total mass of the lubricant composition.

Applications As already indicated, lubricant compositions suitable for use in the present invention as already described are used as lubricants for propulsion systems of electric or hybrid vehicles, more particularly for motors and power electronics. be.

Accordingly, the present invention provides sterically hindered amine or phenolic functional groups, especially as already defined, for lubricating propulsion systems of electric or hybrid vehicles, in particular electric motors and power electronics of electric or hybrid vehicles. and one or more amine-based and/or sulfur-based antiwear additives, preferably dimercaptothiazole derivatives, of a lubricant composition as defined above. Regarding use.

As schematically presented in FIG. 1, the propulsion system of an electric or hybrid vehicle comprises in particular an electric motor section (1), an electric battery (2) and a transmission, in particular a speed reducer (3).

An electric motor typically comprises power electronics (11) connected to a stator (13) and a rotor (14). The stator comprises coils, in particular copper coils, which are powered by alternating current. This makes it possible to generate a rotating magnetic field. For its part, the rotor comprises coils, permanent magnets or other magnetic material and is arranged to rotate by a rotating magnetic field.

A rolling bearing (12) is generally installed between a stator (13) and a rotor (14). The transmission, in particular the gearbox (3), makes it possible to reduce the rotational speed at the outlet of the electric motor and to adapt the speed transmitted to the wheels, while at the same time controlling the speed of the vehicle. .

Rolling bearings (12) are particularly subjected to high mechanical stresses and suffer from fatigue wear problems. Rolling bearings therefore need to be lubricated in order to increase their service life. Also, speed reducers are subjected to high frictional stresses and need to be properly lubricated to prevent premature failure.

The present invention therefore provides a composition as already described, in particular for lubricating electric motors of electric or hybrid vehicles, in particular for lubricating rolling bearings located between rotor and stator of electric motors. regarding the use of

The invention also relates to the use of a composition as already described for lubricating transmissions, in particular reduction gears, of electric or hybrid vehicles.

Advantageously, the composition according to the invention can therefore be used in various parts of propulsion systems of electric or hybrid vehicles, in particular rolling bearings located between the rotor and the stator of electric motors of electric or hybrid vehicles, and/or Or it can be used to lubricate transmissions, in particular reduction gears.

Advantageously, as already mentioned, the lubricant composition according to the invention has excellent anti-wear and anti-corrosion performance.

According to another of its aspects, the invention also provides at least one part of the propulsion system of an electric or hybrid vehicle, in particular a rolling bearing located between the rotor and the stator of an electric motor; In particular it relates to a method for lubricating a speed reducer, comprising at least one step of placing at least said component in contact with a composition as already described.

Accordingly, the present invention is directed to at least one component of the propulsion system of an electric or hybrid vehicle, in particular a rolling bearing located between the rotor and the stator of an electric motor; A method for simultaneously reducing corrosion is proposed, comprising at least one step of placing at least said component in contact with a composition as already described.

All features and preferences described for the composition used according to the invention and its use also apply to this method.

According to a particular embodiment, the composition according to the invention may have good electrical insulating properties in addition to lubricating properties.

According to this embodiment, the composition according to the invention is used for lubricating one or more parts of the propulsion system of an electric or hybrid vehicle, in particular sensors and solenoid valves of motors, rolling bearings, but also of electric motors. For lubricating also the windings located between the rotor and the stator, or for lubricating transmissions, in particular gears, sensors, solenoid valves or speed reducers found in electric or hybrid vehicles, and at least of said propulsion system. It can be used simultaneously to electrically insulate one component, in particular a battery.

^In the context of such implementation variants, the lubricant composition under consideration according to the invention advantageously has a It has a kinematic viscosity between ² /sec.

The above uses may be combined, the compositions already described may be used both as lubricants and electrical insulators, but also as coolants for motors, batteries and transmissions of electric or hybrid vehicles. It is understood that there is

According to the invention, specific, advantageous or preferred features of the composition according to the invention make it possible to define uses according to the invention which are also specific, advantageous or preferred.

The invention will now be illustrated with the following examples, which, of course, are given as non-limiting illustrations of the invention.

Various compositions were evaluated:
- composition C1 with amine-based and sulfur-based antiwear additives of the dimercaptothiadiazole type and without additives with sterically hindered amine or phenol functional groups;
- composition C2 comprising said antiwear additive of dimercaptothiadiazole type and an additive with sterically hindered amine functionality (p,p'-butyloctyldiphenylamine);
- Composition C3 comprising said antiwear additive of the dimercaptothiadiazole type and an additive with a sterically hindered phenolic function (octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate).

Compositions C1-C3 comprise Group V base oils in addition to the compounds described above.

The compositions and amounts (expressed as mass percentages) are shown in Table 2 below.

Evaluation Method for Evaluation of Corrosion Resistant Properties The corrosive (or erosive) power of a composition is evaluated by a test that involves examining the variation in electrical resistance of a copper wire of given diameter as a function of the duration of immersion in the composition. can be evaluated by This change in electrical resistance directly correlates with the change in diameter of the test wire. In the context of the present invention, the wire diameter chosen is 70 μm.

In the case of the invention, the copper wire is immersed in a test tube containing 20 mL of the test composition (compositions C2 and C3 are compositions according to the invention and composition C1 is the composition that serves as a comparison).

Wire resistance is measured using an ohmmeter.

The measured current is 1mA.

The temperature of the test composition is 150°C.

The copper wire resistance is given by this formula (1):

(where R is the resistance, ρ is the resistivity of copper, L is the length of the wire, and S is the cross-sectional area)
Calculate by

In this formula (1), ρ and L are constant. The resistance R is therefore inversely proportional to the cross-sectional area of the immersed wire.

The wire diameter is calculated from the cross-sectional area (equation (2)).

(where D is the diameter of the wire).

Inserting equation (2) into equation (1), we obtain the relationship between resistance and diameter (equation (3)).

Therefore, if the wire is corroded by the test composition, the diameter of the wire will decrease and thus the resistance value will increase.

By monitoring the resistance, it is possible to monitor the change in diameter of the wire, which reflects the corrosion conditions experienced by the immersed wire.

The wire diameter loss is therefore calculated directly from the measured resistance.

If the measured resistance is infinite, this is an open circuit. The line is therefore broken, which defines very severe corrosion.

Results The results are summarized in the table below and expressed in μm (loss in diameter). The lower the value obtained, the better the corrosion resistance properties of the evaluated composition.

A composition is considered "non-corrosive" if the copper wire investigated loses less than 2 μm in diameter after 80 hours of immersion in the composition, in particular less than 0.3 μm after 20 hours of immersion.

These results demonstrate that the addition of sterically hindered amines or compounds with phenolic functionality according to the present invention makes it possible to reduce the corrosion effects induced by amine- and sulfur-based antiwear additives. is.

1 electric motor section
2 electric batteries
3 Reducer
11 Power Electronics
12 Rolling bearing
13 Stator
14 Rotor

Claims (10)

At least one sterically hindered amine as an anticorrosion additive in a lubricant composition for an electric or hybrid vehicle propulsion system and containing one or more amine-based and/or sulfur-based antiwear additives or use of at least one compound with a phenolic functional group. wherein said compound having at least one sterically hindered amine or phenolic function is selected from aromatic amines, especially diarylamine compounds, more particularly diphenylamine compounds, sterically hindered phenols, especially alkylphenols, and mixtures thereof. Use according to paragraph 1. Said compound of the aromatic amine type is a diarylamine, preferably of the formula:

(Wherein, R ₆ and R ₇ are, independently of each other,
- a hydrocarbon selected from hydrocarbon-based groups, in particular alkyl or alkenyl groups containing 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms, preferably para to the amine function; a phenyl group, optionally substituted by a base group; and
- a hydrocarbon selected from hydrocarbon-based groups, in particular alkyl or alkenyl groups containing 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms, preferably para to the amine function; optionally substituted on the base group, selected from naphthyl groups),
More preferentially formula (I):

(wherein R ₁ and R ₂ are, independently of each other, hydrogen atoms; linear or branched alkyl or alkenyl groups, preferably 1 to 12 carbon atoms, preferably 3 to 10 alkyl groups containing carbon atoms);
Specifically, formula (I'):

(Wherein, R ₁ and R ₂ may be the same or different and represent a linear or branched C ₁ -C ₁₂ , preferably C ₃ -C ₁₀ alkyl group, for example a linear linear or branched octyl and butyl groups)
3. Use according to claim 1 or 2, selected from diarylamines of Said compound of the sterically hindered phenol type has the formula (II'):

(In the formula,
at least one of R ¹ and R ² represents a C ₁ -C ₁₀ alkyl group, preferably a C ₁ -C ₆ alkyl group, preferably a C ₄ alkyl group, such as tert-butyl; or a hydroxyl group;
n is an integer from 0 to 3;
R is, independently of each other, one which may be substituted with one or more C ₂ -C ₁₀ alkoxycarbonyl groups, such as an octyloxycarbonyl group, and/or itself with one or more alkyl groups; or a C ₁ -C ₁₀ alkyl group, optionally substituted with multiple aryl groups; and a hydroxyl group)
4. Use according to claim 2 or 3, which is a compound of Said compounds with sterically hindered amine or phenol functional groups are p,p'-butyloctyldiphenylamine, octyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 2,6-di-tert-butylphenol , and mixtures thereof. Said amine-based and/or sulfur-based antiwear additive, alone or as a mixture, is a dimercaptothiadiazole derivative, especially of the formula:

(wherein the R ₁ groups are, independently of each other, hydrogen atoms, 1 to 24, preferably 2 to 18, more preferentially 4 to 16, even more preferentially 8 to 12 represents a straight-chain or branched alkyl or alkenyl group containing carbon atoms or an aromatic substituent, wherein n is independently of each other an integer equal to 1, 2, 3 or 4, n is preferably is equal to 1)
6. Use according to any one of claims 1 to 5, selected from 2,5-dimercapto-1,3,4-thiadiazole derivatives having 0.01% to 5%, especially 0.1% to 3%, more particularly 0.1% to 1% by weight of said compound having a sterically hindered amine or phenolic function, relative to the total weight of the lubricant composition. % by weight; and/or said amine-based and/or sulfur-based antiwear additive is present in an amount of 0.01% by weight to 5% by weight, based on the total weight of the lubricant composition, in particular Use according to any one of claims 1 to 6, present in a content in the range from 0.1% to 3% by weight, more particularly from 0.1% to 1% by weight. One with at least one sterically hindered amine or phenolic function as an anti-corrosion additive for lubricating propulsion systems in electric or hybrid vehicles, in particular for lubricating electric motors and power electronics in electric or hybrid vehicles Or use of a lubricant composition comprising multiple compounds and one or more amine-based and/or sulfur-based antiwear additives. The compound having at least one sterically hindered amine or phenolic functionality is as defined in any one of claims 2 to 5 and 7; and/or amine-based and/or sulfur-based antiwear additives 9. Use according to claim 8, wherein the agent is as defined in claim 6 or 7. 10. Use according to claim 8 or 9, for lubricating rolling bearings located between the rotor and stator of an electric motor and/or transmissions, in particular reduction gears, of electric or hybrid vehicles.

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