KR20230042288A - Lubricant composition for automotive transmissions having improved anti-corrosion properties - Google Patents

Abstract

여기서, R¹, R², R³ 및 R⁴는 각각 독립적으로 다음 기들 중에서 선택될 수 있고: C₁-C₂₀ 알킬, C₃-C₂₂ 알케닐, C₆-C₄₀ 시클로알킬, C₇-C₄₀ 시클로알케닐, C₁-₂₀ 메톡시 알킬 글리콜 에테르 및 Y-OH; Y는 다음 기들 중에서 선택되고: C₂-C₄₀ 알킬렌, C₂-C₄₀ 알킬 락톤, -R⁷-N(R⁸)-R⁹-, 여기서 R⁷, R⁸ 및 R⁹는 각각 독립적으로 수소, C₁-C₂₀ 알킬, C₃-C₂₂ 알케닐, C₆-C₄₀ 시클로알킬, C₇-C₄₀ 시클로알케닐, C₁-₂₀ 메톡시 알킬 글리콜 에테르 중에서 선택되고; m은 2 내지 100의 정수이고, n은 1 내지 1000의 정수인 윤활제 조성물에 관한 것이다.The present invention relates to a lubricant composition comprising at least one base oil, at least one dispersant and at least one phosphite polymer of formula (I):
[Formula 1]

wherein R ¹ , R ² , R ³ and R ⁴ may each independently be selected from the following groups: C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl, C ₆ -C ₄₀ cycloalkyl, C ₇ -C ₄₀ cycloalkenyl _{, C 1-20 methoxy} alkyl glycol ether and Y-OH; Y is selected from the following groups: C ₂ -C ₄₀ alkylene, C ₂ -C ₄₀ alkyl lactone, -R ⁷ -N(R ⁸ )-R ⁹ -, wherein R ⁷ , R ⁸ and R ⁹ are each independently is selected from hydrogen, C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl _, C ₆ -C ₄₀ cycloalkyl, C ₇ -C ₄₀ cycloalkenyl, and C _1-20 methoxy alkyl glycol ether; m is an integer from 2 to 100, and n is an integer from 1 to 1000.

Description

Lubricant composition for automotive transmissions having improved anti-corrosion properties

The present invention relates to the field of lubricant compositions, in particular for the lubrication of motor vehicles and more particularly transmission components of motor vehicles, in particular gearings of transmissions of internal combustion engines or electric motors.

Transmission components in automobiles operate under heavy loads and high speeds. Accordingly, these transmission oils must have particularly good performance in order to protect parts against wear and fatigue, and in particular to protect gear teeth against spalling.

Spalling occurs after a long aging time preceding visible deterioration. This mechanism is not well known, but the phenomenon begins with the initiation of a crack at a certain depth below the surface, which then propagates and causes a sudden fall-off of a part of the material when a normal crack occurs on the surface. there is.

Prevention of this phenomenon requires reduction of contact stress by proper geometry of the parts, and reduction of friction to prevent adhesion. The lubricant composition participates in this prevention process primarily through the physicochemical reactivity of the additives included therein.

Typically, the additions consist of sulfur-, phosphorus-, or boron-containing antiwear and extreme pressure additives that impart protective properties against spalling to the transmission fluid. Other additives contained in the lubricant composition may also have a negative or positive effect on the propagation of cracks within the component, and thus spalling.

Throughout their lifetime of use, lubricant compositions used in transmission parts may begin to deteriorate.

Accordingly, an object of the present invention is to provide a lubricant composition for a manual or automatic transmission, in particular for a gear unit of a transmission of an internal combustion engine or an electric motor, which has excellent anti-corrosion properties, especially with respect to copper.

Document WO 2010/126760 covers a polymer of the phosphorus ester type comprising a base oil and the condensation reaction product of an acid or phosphorus ester with a diol in which two hydroxy functionalities are separated by a chain of 4 to 100 carbon atoms. A lubricant composition is described.

Document WO 2016/089565 describes a lubricant composition comprising a base oil and a phosphite ester composition comprising a condensation reaction product of at least two diols with an acid or phosphorus ester.

Both documents are not about anticorrosion properties and do not specifically describe phosphite polymers of formula (I) as described in the present invention.

More specifically, the present invention,

- at least one base oil,

- at least one dispersant,

- at least one phosphite polymer of formula (I)

It relates to a lubricant composition comprising:

[Formula 1]

In the above formula:

- R ¹ , R ² , R ³ and R ⁴ may each independently be selected from the following groups: C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl, C ₆ -C ₄₀ cycloalkyl, C ₇ - C ₄₀ cycloalkenyl _, C _1-20 methoxy alkyl glycol ether and Y—OH (serving as end groups);

- Y is selected from the following groups: C ₂ -C ₄₀ alkylene, C ₂ -C ₄₀ alkyl lactone, -R ⁷ -N(R ⁸ )-R ⁹ -, wherein R ⁷ , R ⁸ and R ⁹ are each independently selected from hydrogen, C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl _, C ₆ -C ₄₀ cycloalkyl, C ₇ -C ₄₀ cycloalkenyl, C _1-20 methoxy alkyl glycol ether;

- m is an integer from 2 to 100;

- n is an integer from 1 to 1000;

In one embodiment of the present invention, the polymer of formula (I) has a weight average molecular weight of less than 30000 g/mol.

In one embodiment of the present invention, the phosphite polymer corresponds to 0.01 to 10% by weight of the total weight of the lubricant composition.

In one embodiment of the present invention, the dispersant is a boron-containing dispersant, preferably in a boronated and optionally phosphorylated succinimide, preferably in a boronated and optionally phosphorylated polyisobutylene succinimide. is chosen

In one embodiment of the present invention, the lubricant composition comprises 5 to 9150 ppm by weight, preferably 5 to 4500 ppm by weight of phosphorus based on the total weight of the lubricant composition.

In one embodiment of the present invention, the lubricant composition comprises at least one antiwear additive selected from phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, phosphorus-amine antiwear additives, sulfur-amine antiwear additives, and mixtures thereof. , preferably further included in a ratio of 0.01 to 5% by weight relative to the total weight of the lubricant composition.

In one embodiment of the present invention, the lubricant composition comprises 5 to 4000 ppm by weight of bow, preferably 7 to 1000 ppm by weight of sulfur, more preferably 10 to 800 ppm by weight, based on the total weight of the lubricant composition. contains sulfur in

In one embodiment of the present invention, the lubricant composition

With respect to the total weight of the lubricant composition,

- 70 to 99% by weight of one or more base oils, and

- 0.01 to 10% by weight of a phosphite polymer,

- 0.01 to 5% by weight of dispersant(s), preferably comprising at least one boron-containing dispersant,

- optionally, from 0.01 to 5% by weight of antiwear additive(s) selected from phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, phosphorus-amine antiwear additives, sulfur-amine antiwear additives, and mixtures thereof;

- optionally, from 1 to 30% by weight of one or more functional additives, preferably selected from viscosity index improving additives, antioxidant additives, antifoam additives, boron-free dispersants, detergents, viscosity control additives and mixtures thereof

includes

The present invention also relates to the use of a phosphite polymer in combination with a dispersant for improving the corrosion resistance properties of a lubricant composition comprising at least one base oil, said phosphite polymer corresponding to formula (I):

In the above formula:

- R ¹ , R ² , R ³ and R ⁴ may each independently be selected from the following groups: C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl, C ₆ -C ₄₀ cycloalkyl, C ₇ - C ₄₀ cycloalkenyl _{, C 1-20 methoxy} alkyl glycol ether and Y—OH;

- Y is selected from the following groups: C ₂ -C ₄₀ alkylene, C ₂ -C ₄₀ alkyl lactone, -R ⁷ -N(R ⁸ )-R ⁹ -, wherein R ⁷ , R ⁸ and R ⁹ are each independently selected from hydrogen, C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl _, C ₆ -C ₄₀ cycloalkyl, C ₇ -C ₄₀ cycloalkenyl, C _1-20 methoxy alkyl glycol ether;

- m is an integer from 2 to 100;

- n is an integer from 1 to 1000;

The present invention also relates to the use of the lubricant composition of the invention for lubricating at least one mechanical part of a motor vehicle, preferably incorporated in a transmission component of a motor vehicle, preferably in a gear unit of a motor vehicle.

The lubricant composition of the present invention has the advantage of exhibiting very good properties of reducing spalling, especially when used under heavy load and high speed.

Lubricant compositions of the present invention typically have good durability.

The lubricant composition of the present invention has improved resistance to copper corrosion. Copper is especially present in the transmission system of electric vehicles.

Hereinafter, the expressions "from... to...", "ranging from... to..." and "changing from... to..." are equivalent and are intended to include boundaries unless otherwise specified. do.

Unless otherwise indicated, amounts of product are expressed by weight relative to the total weight of that product.

the present invention

- at least one base oil,

- at least one phosphite polymer corresponding to formula (I),

- at least one dispersant, preferably a boron-containing dispersant,

- optionally at least one antiwear additive

It relates to a lubricant composition comprising a.

phosphite polymer

The lubricant composition of the present invention comprises at least one phosphite polymer corresponding to Formula (I):

[Formula 1]

In the above formula:

- R ¹ , R ² , R ³ and R ⁴ may each independently be selected from the following groups: C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl, C ₆ -C ₄₀ cycloalkyl, C ₇ - C ₄₀ cycloalkenyl _, C _1-20 methoxy alkyl glycol ether and Y—OH (serving as end groups);

- Y is selected from the following groups: C ₂ -C ₄₀ alkylene, C ₂ -C ₄₀ alkyl lactone, -R ⁷ -N(R ⁸ )-R ⁹ -, wherein R ⁷ , R ⁸ and R ⁹ are each independently selected from hydrogen, C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl _, C ₆ -C ₄₀ cycloalkyl, C ₇ -C ₄₀ cycloalkenyl, C _1-20 methoxy alkyl glycol ether;

- m is an integer from 2 to 100;

- n is an integer from 1 to 1000;

In the context of this invention, "alkyl" means a straight or branched, non-cyclic saturated hydrocarbon chain, optionally containing one or more heteroatoms such as oxygen, nitrogen or sulfur atoms. Preferably, alkyl consists of carbon atoms and hydrogen atoms.

In the context of this invention, "alkenyl" means a straight or branched, non-cyclic unsaturated hydrocarbon chain, optionally containing one or more heteroatoms such as oxygen, nitrogen or sulfur atoms. Preferably, alkenyl consists of carbon atoms and hydrogen atoms.

In the context of this invention, "cycloalkyl" means a saturated monocyclic or polycyclic group optionally having one or more alkyl or alkenyl substituents, the ring(s) being itself an oxygen, nitrogen or sulfur atom. It may be substituted with one or more heteroatoms. Preferably, cycloalkyl consists of carbon atoms and hydrogen atoms.

In the context of this invention, “cycloalkenyl” means an unsaturated monocyclic or polycyclic group optionally having one or more alkyl or alkenyl substituents, the ring(s) itself containing an oxygen, nitrogen or sulfur atom may be substituted with one or more heteroatoms of the same type. Preferably, cycloalkenyl consists of carbon atoms and hydrogen atoms.

In the context of the present invention, a “C _i -C _j group” is a group having from i to j carbon atoms.

In a preferred embodiment, the Y group is selected from alkylenes having 2 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms.

In one embodiment, m ranges from 4 to 100.

In one embodiment, the phosphite polymer of formula (I) has a weight average molecular weight of less than 30000 g/mol, preferably in the range of 3000 to 20000 g/mol. Weight average molecular weight can be determined by size exclusion chromatography.

In one embodiment, the phosphite polymer of formula (I) has a number average molecular weight of less than 10000 g/mol, preferably in the range of 1000 to 5000 g/mol. Number average molecular weight can be determined by size exclusion chromatography.

In one embodiment, the phosphite polymer of formula (I) has a polydispersity index of 1 to 5, preferably 2 to 4.

Preferably, the phosphite polymer of formula (I) is less than 2% by weight, preferably less than 1% by weight, even less than 0.7% by weight of (alkyl), relative to the total weight of the phosphite polymers in formula (I). contains a phenol group.

Preferably, the phosphite polymer of formula (I) is completely free of the (alkyl)phenol groups and other aromatic groups.

Typically, the phosphite polymer is in liquid form.

In one embodiment, the phosphite polymer has a phosphorus content ranging from 0.5 to 20% by weight, preferably from 1 to 10% by weight, based on the total weight of the phosphite polymer.

The phosphite polymer used in the present invention can be obtained by the method described in document WO2011102861. In particular, the polymer may be obtained using the method described in paragraphs 27 to 32 of that document.

The synthesis of the polymer of formula (I) generally involves the addition of triphenyl phosphite (or any other suitable alkyl or aryl phosphite) to a saturated or unsaturated alcohol, or a polyethylene or polypropylene glycol ether, and a diol or diol polymer H(OY) _m OH (where m and Y are as previously defined) and a suitable basic catalyst at a temperature of 20 to 250 ℃, preferably 50 to 185 ℃ means a transesterification that can be reacted. Among non-limiting examples of saturated or unsaturated alcohols, decyl, isodecyl, lauryl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, stearyl, isostearyl, oleic alcohols , monohydroxylated glycol ethers.

Preferably, the lubricant composition of the present invention comprises 0.01 to 10% by weight of phosphite polymer(s) relative to the total weight of the lubricant composition.

base oil(s)

The lubricant composition of the present invention comprises one or more base oils, preferably in an amount of at least 70% by weight, preferably from 70 to 99% by weight, more preferably from 80 to 98% by weight relative to the total weight of the lubricant composition. do.

The base oil may be selected from base oils typically used in the lubricating oil sector, such as mineral, synthetic or natural animal or vegetable oils, or mixtures thereof.

It may 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 contemplated in the present invention may be oils of mineral or synthetic origin, in particular belonging to Groups I to V (or their equivalents in the AITEL classification) of the groups defined by the API classification, and are provided in the following Table 1: , or mixtures thereof.

saturation content sulfur content Viscosity Index (VI) group I
mineral oil < 90　% > 0,03　% 80 ≤ I < 120 group II
hydrocracked oil ≥0% ≤0,03% 80 ≤ VI < 120 group III
Hydrocracked or hydroisomerized oil ≥0% ≤0,03% ≥120 group IV Polyalphaolefin (PAO) group V Ethers and other bases not included in Groups I to IV

Mineral base oils are obtained by atmospheric or vacuum distillation of crude oil followed by solvent extraction, deasphalting, solvent dewaxing, hydrotreatment, hydrocracking, hydroisomerization, and Includes all types of base oils obtained by hydrofinishing.

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

Except for the fact that the different base oils for forming the compositions used in the present invention should have properties with respect to viscosity, viscosity index or oxidation resistance particularly suited to use in the propulsion systems of electric or hybrid vehicles, their use There are generally no restrictions on

The base oils of the compositions used in the present invention may also polymerize or copolymerize some esters of carboxylic acids and alcohols, polyalphaolefins (PAOs), and alkylene oxides having from 2 to 8 carbon atoms, particularly from 2 to 4 carbon atoms. synthetic oils, such as polyalkylene glycols (PAGs) obtained by

PAOs used as base oils are obtained, for example, from monomers having from 4 to 32 carbon atoms, for example octene or decene. The weight average molecular weight of the PAO can vary widely. Preferably, the weight average molecular weight of the PAO is lower than 600 Da. The weight average molecular weight of the PAO may also range from 100 to 600 Da, 150 to 600 Da, or 200 to 600 Da.

Advantageously, the base oil or oils of the lubricant composition of the present invention may be selected from among Group II or Group III base oils.

In an alternative embodiment, the base oil or oils of the composition used in the present invention are selected from polyalphaolefins (PAOs), polyalkylene glycols (PAGs), and esters of carboxylic acids and alcohols.

dispersant

The lubricant composition of the present invention includes at least one dispersant. Typically, the dispersant will allow suspension retention and release of insoluble solid contaminants formed by secondary products of oxidation that form when the lubricant composition is in service.

In one embodiment, the dispersant may be selected from succinimide dispersants, succinic acid ester dispersants, ester-amide succinic acid dispersants, Mannich base dispersants, and mixtures thereof, and the dispersant may be in boronated form and/or phosphorylated form. can

Accordingly, the lubricant composition of the present invention comprises at least one boron-containing dispersant and/or at least one boron-free dispersant, preferably at least one boron-containing dispersant.

"Boron-free dispersant" means, in the context of the present invention, a dispersant additive free of boron atoms, which dispersant may contain one or more phosphorus atoms.

In one embodiment, the boron-free dispersant is selected from succinimide compounds such as polyisobutylene succinimide (PIBSIs).

“Boron-containing dispersant” means, in the context of the present invention, a dispersing additive comprising at least one boron atom, which dispersant may contain one or more phosphorus atoms, in which case the terms boronated and phosphorylated dispersant used

In one embodiment, the boron-containing dispersant is in boronated succinimide compounds, such as boronated polyisobutylene succinimides (PIBSIs), or boronated and phosphorylated polyisobutylene succinimides (PIBSIs). selected from boron-phosphorus compounds.

In one embodiment, the boron-containing compound is a reaction product of PIBSIs and a boronated polyalkylene amine (PIBSA/borated PAM), a reaction product of PIBSA and a borated and phosphorylated polyalkylene amine (PIBSA/borated-phosphorylated PAM).

In one embodiment referring to a (boron-containing and/or boron-free) dispersant having polyisobutylene chains (PIB), preferably said PIB chains have a molar mass ranging from 750 to 3000 g/mol.

In one embodiment, the boron-containing dispersant has a boron content ranging from 0.1 to 10% by weight, preferably from 0.2 to 5% by weight, more preferably from 0.25 to 3% by weight, based on the total weight of the boron-containing dispersant. have

In one embodiment, when the boron-containing dispersant is selected from boron-phosphorus compounds, the boron content is preferably from 0.1 to 10% by weight, preferably from 0.2 to 5% by weight, based on the total weight of the boron-containing dispersant. , more preferably 0.25 to 3% by weight, and the phosphorus content is preferably 0.05 to 5% by weight, preferably 0.1 to 3% by weight, more preferably 0.2 to 1.5% by weight relative to the total weight of the boron-containing dispersant. % by weight.

In one particular embodiment, the boron-containing dispersant is free of phosphorus.

In one embodiment, the lubricant composition comprises 0.01 to 5% by weight of boron-containing dispersant(s) and/or boron-free dispersant(s), preferably 0.1 to 4% by weight, relative to the total weight of the boron-containing dispersant. % of boron-containing dispersant(s) and/or boron-free dispersant(s).

The inventors have discovered that the combination of a dispersant, preferably a boron-containing dispersant, with a phosphite polymer of formula (I) allows for improved anti-corrosion properties of the lubricant composition.

antiwear additives

The antiwear additive optionally used in the lubricant composition of the present invention is selected from phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, and mixtures thereof.

It should be noted that the antiwear additive optionally added to the lubricant composition of the present invention is typically different from the phosphite polymer of formula (I).

In the context of the present invention, "phosphorus antiwear additive" refers to an antiwear additive comprising at least one phosphorus atom and no sulfur, said phosphorus antiwear additive optionally containing (in addition to carbon and hydrogen atoms) one or more nitrogen atoms. can include In this case, it may be termed "phosphor-amine antiwear additive".

In the context of the present invention, "sulfur antiwear additive" refers to an antiwear additive comprising at least one sulfur atom and no phosphorus, said sulfur antiwear additive optionally containing (in addition to carbon and hydrogen atoms) one or more nitrogen atoms. can include In this case, it can be named "sulfur-amine antiwear additive".

In the context of the present invention, "sulfur-phosphorus antiwear additive" refers to an antiwear additive comprising at least one phosphorus atom and at least one sulfur atom, said sulfur-phosphorus antiwear additive comprising (in addition to carbon and hydrogen atoms) one or more Nitrogen atoms may optionally be included. In this case, it can be named "sulfur-phosphorus-amine antiwear additive".

Among the phosphorus antiwear additives, mention may be made of phosphates, phosphites and phosphonates. These terms include phosphoric acid, phosphorous acid, phosphonic acid and mono-, di- and triesters thereof, such as alkyl phosphates, alkyl phosphonates, and salts thereof, such as For example, it refers to an amine salt.

The sulfur-phosphorus antiwear additives optionally used in the present invention may be (mono- or di-) thiophosphates and thiophosphites, the terms of which are thiophosphoric acid and thiophosphorous acid, the names of these acids. esters, salts thereof, dithiophosphites and dithiophosphates.

Examples of sulfur-phosphorus antiwear additives include monobutylthiophosphate, monooctylthiophosphate, monolaurylthiophosphate, dibutylthiophosphate, dilaurylthiophosphate, tributylthiophosphate, trioctylthiophosphate, triphenylthiophosphate, Monooctylthiophosphite, trilaurylthiophosphite, monolaurylthiophosphite, monobutylthiophosphite, dibutylthiophosphite, dilaurylthiophosphite, tributylthiophosphite, trioctylthiophosphite, Triphenylthiophosphite, trilaurylthiophosphite and salts thereof may be mentioned.

Examples of ester salts of thiophosphoric acid and thiophosphorous acid are those obtained by reaction with zinc oxide or zinc chloride or nitrogen-containing compounds such as ammonia or amines.

In one particular embodiment, the antiwear additive(s) used in the present invention are selected from sulfur-phosphorus antiwear additives, sulfur-amine antiwear additives, and mixtures thereof.

For example, the lubricant composition of the present invention may contain 0.01 to 5% by weight of antiwear additive(s), preferably 0.05 to 3% by weight of antiwear additive(s), based on the total weight of the lubricant composition.

The amount of antiwear additive can be adjusted to obtain a phosphorus content of 5 to 9150 ppm by weight in the lubricant composition. Preferably, the phosphorus content in the lubricant composition of the present invention is 5 to 4500 ppm by weight based on the total weight of the lubricant composition.

We have found that the combination of a phosphite polymer of formula (I) with a boron-containing dispersant and a phosphorus, sulfur or sulfur-phosphorus antiwear additive further improves the corrosion resistance properties of the lubricant composition.

additional additives

The lubricant composition of the present invention, different from the phosphite polymer and antiwear additives defined herein, may also include any type of functional additive suitable for use in lubricants for automobiles, particularly manual or automatic transmissions of automobiles.

Such additives known to those skilled in the art of automotive lubrication are selected from detergents, antioxidants, pour point depressants, defoaming agents, viscosity index improvers, and mixtures thereof. It can be.

Advantageously, the composition of the present invention comprises at least one functional additive selected from detergents, antioxidants, pour point depressants, antifoams, viscosity index improvers, and mixtures thereof.

Typically, when present, these additional functional additives (together) represent from 1 to 30% by weight, preferably from 1.5 to 25% by weight, more preferably from 2 to 20% by weight relative to the total weight of the lubricant composition.

These additives, alone and/or in commercial lubricant formulations for automotive use, have performance levels as defined by the European Automobile Manufacturers' Association (ACEA) and/or the American Petroleum Institute (API), well known to those skilled in the art. Or it may be added in the form of a mixture such as those already commercially available.

The lubricant composition of the present invention may also include at least one antioxidant additive.

The anti-oxidant additives generally allow for a delay in decomposition of the composition during operation. This degradation can in particular be interpreted as the formation of deposits, the presence of sludge or an increase in the viscosity of the composition.

Antioxidant additives act in particular as radical inhibitors or hydroperoxide decomposers. Among the commonly used antioxidant additives, phenol type antioxidant additives, amine type antioxidant additives, and sulfur-phosphorus antioxidant additives may be mentioned. Some of these antioxidant additives, for example sulfur-phosphorus antioxidant additives, can produce ash. Phenolic antioxidant additives may be ash free or in the form of neutral or basic metal salts. The antioxidant additives are in particular sterically hindered phenols, sterically hindered phenol esters, sterically hindered phenols with thioether bridges, diphenylamines, diphenylamines substituted with at least one C1 to C12 alkyl group, N,N'-dialkyl- aryl-diamines, and mixtures thereof.

Preferably, in the present invention, the sterically hindered phenol is such that at least one adjacent carbon of the carbon having an alcohol functional group is at least one C ₁ -C ₁₀ alkyl group, preferably a C ₁ -C ₆ alkyl group, more preferably a C 1 -C 10 alkyl group. ₄ It is selected from compounds containing a phenol group substituted with an alkyl group, preferably a tert-butyl group.

Amine compounds form another class of antioxidant additives that can be used optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example, of the formula NR ¹⁰ R ¹¹ R ¹² , wherein R ¹⁰ is an optionally substituted aliphatic or aromatic group, R ¹¹ is an optionally substituted aromatic group, and R ¹² is A hydrogen atom, an alkyl group, an aryl group, or a group of the formula R ¹³ S(O) _z R ¹⁴ , wherein R ¹³ is an alkylene group or an alkenylene group, R ¹⁴ is an alkyl group, an alkenyl group, or an aryl group, z is 0, 1 or 2) is an aromatic amine having

Sulfurized alkyl-phenols or alkali or alkaline earth metal salts thereof may also be used as antioxidant additives.

Another class of antioxidant additives are copper-containing compounds, such as copper thio- or dithio-phosphates, salts of copper and carboxylic acids, copper acetylacetonates, dithiocarbamates, sulfonates, phenates. Salts of copper I and II, succinic acid salts or anhydrides may also be used.

The lubricant composition of the present invention may include any type of antioxidant known to those skilled in the art.

Advantageously, the lubricant composition comprises at least one ash-free antioxidant additive.

The lubricant composition of the present invention may contain from 0.5 to 2% by weight of at least one antioxidant additive, based on the total weight of the composition.

The lubricant composition of the present invention may also include at least one detergent additive.

Detergent additives generally allow for reduced formation of deposits on the surface of metal parts by dissolving secondary products of oxidation and combustion.

Detergent additives that can be used in the lubricant composition of the present invention are generally known to those skilled in the art. The detergent additive may be an anionic compound having a long lipophilic hydrocarbon chain and a hydrophobic head. The relevant cation may be a metal cation of an alkali or alkaline earth metal.

The detergent additive is preferably selected from alkali 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.

These metal salts generally contain a stoichiometric amount or an excess of the metal, ie an amount greater than the stoichiometric content. These are then overbased detergents; Excess metals imparting overbased properties to detergent additives are usually oil-insoluble metal salts such as carbonates, hydroxides, oxalates, acetates, glutamates. ), preferably in the carbonate form.

Lubricant compositions suitable for the present invention may include, for example, from 0.5 to 4% by weight of detergent additives relative to the total weight of the composition.

Additionally, the lubricant composition of the present invention may include at least one boron-free dispersant.

The boron-free dispersant may be selected from Mannich base or succinimide type compounds such as polyisobutylene succinimide (PIBSIs).

The lubricant composition may include, for example, 0.2 to 10% by weight of a boron-free dispersant based on the total weight of the composition.

The lubricant composition of the present invention may also include at least one antifoaming agent.

The antifoaming agent may be selected from silicone.

The lubricant composition of the present invention may include 0.01 to 2% by weight, or 0.01 to 5% by weight, preferably 0.1 to 1.5% by weight, or 0.1 to 2% by weight of the defoaming agent, relative to the total weight of the composition.

The lubricant composition of the present invention may also include at least one pour point depressant additive (PPD).

By slowing the formation of paraffin crystals, pour point depressing additives generally improve the cold properties of the composition. As examples of pour point depressing additives, mention may be made of alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes, alkylated polystyrenes.

The lubricant composition of the present invention may also include at least one viscosity index improving additive (VI improver). As examples of VI improvers, mention may be made of polymethacrylates, polyisobutenes or fatty acid esters. When present, these additives may represent from 1 to 25% by weight of the total weight of the lubricant composition.

In formulating the lubricant composition, after the phosphite polymer, the dispersant and optionally the antiwear additive are added to the base oil or base oil mixture, any other additional additives may be added.

Alternatively, the phosphite polymer, dispersant and optionally antiwear additives may be added to typical already existing lubricant formulations, in particular comprising one or more base oils and optionally further additives.

Alternatively, the phosphite polymer, dispersant and optionally antiwear additives as defined herein are combined with one or more additional additives, if included, and the “package” of additives thus formed is added to the base oil or base oil mixture. can

Advantageously, the lubricant composition of the present invention has a kinematic viscosity measured at 40° C. according to ASTM D445 ranging from 5 to 300 mm ² /s, in particular from 10 to 25 mm ² /s.

Advantageously, the lubricant composition of the present invention has a kinematic viscosity measured at 100° C. according to ASTM D445 ranging from 1 to 20 mm ² /s, in particular from 2 to 15 mm ² /s.

In one particular embodiment, the lubricant composition of the present invention:

- a base oil or mixture of base oils;

- phosphite polymers corresponding to formula (I);

- a boron-containing or boron-free dispersant, optionally selected from boronated and/or phosphorylated PIBSIs;

- optionally, sulfur-phosphorus and/or sulfur-amine antiwear additives;

- optionally, one or more additional additives selected from viscosity index modifiers, detergents, antioxidants, pour point depressants, antifoaming agents and mixtures thereof

It includes or consists of them.

In one particular embodiment, the lubricant composition of the present invention:

- a base oil or mixture of base oils;

- phosphite polymers corresponding to formula (I);

- a boron-containing dispersant, selected from boronated PIBSIs and boronated and phosphorylated PIBSIs;

- optionally, sulfur-phosphorus and/or sulfur-amine antiwear additives;

- optionally, one or more additional additives selected from viscosity index modifiers, detergents, antioxidants, pour point depressants, antifoams and oil mixtures

It includes or consists of them.

In one particular embodiment, the lubricant composition of the present invention:

- at least 70% by weight of a base oil, preferably between 70 and 99% by weight;

- from 0.05 to 10% by weight, in particular from 0.1 to 7% by weight, more particularly from 1 to 5% by weight of a phosphite polymer(s) corresponding to formula (I);

- 0.01 to 5% by weight of a boron-containing and/or boron-free dispersant(s), optionally selected from boronated and/or phosphorylated PIBSIs;

- from 0.05 to 10% by weight, in particular from 0.1 to 7% by weight, more particularly from 1 to 5% by weight of sulfur-phosphorus and/or sulfur-amine antiwear additive(s);

- optionally from 1 to 20% by weight, preferably from 1.5 to 10% by weight, more particularly from 2 to 5% by weight, preferably selected from viscosity index modifiers, detergents, antioxidants, pour point depressants, antifoams, and mixtures thereof , one or more functional additives

It includes or consists of them.

In one particular embodiment, the lubricant composition of the present invention:

- at least 70% by weight of a base oil, preferably between 70 and 99% by weight;

- from 0.05 to 10% by weight, in particular from 0.1 to 7% by weight, more particularly from 1 to 5% by weight of a phosphite polymer(s) corresponding to formula (I);

- 0.01 to 5% by weight of a boron-containing dispersant(s), selected from boronated PIBSIs and boronated and phosphorylated PIBSIs;

- from 0.05 to 10% by weight, in particular from 0.1 to 7% by weight, more particularly from 1 to 5% by weight of sulfur-phosphorus and/or sulfur-amine antiwear additive(s);

- optionally from 1 to 20% by weight, preferably from 1.5 to 10% by weight, more particularly from 2 to 5% by weight, preferably selected from viscosity index modifiers, detergents, antioxidants, pour point depressants, antifoams, and mixtures thereof , one or more functional additives

It includes or consists of them.

In one embodiment, the lubricant composition of the present invention contains 5 to 4000 ppm sulfur by weight, preferably 7 to 1000 ppm sulfur by weight, more preferably 10 to 800 ppm sulfur by weight, based on the total weight of the lubricant composition. include

In one embodiment, the lubricant composition of the present invention comprises from 5 to 9150 ppm by weight of phosphorus, preferably from 5 to 4500 ppm by weight of phosphorus, based on the total weight of the lubricant composition.

In one embodiment, the boron content of the lubricant composition is 5 to 500 ppm by weight, preferably 10 to 300 ppm by weight, based on the total weight of the lubricant composition.

The present invention also relates to a lubricant as defined above, in combination with a boron-containing and/or boron-free dispersant in a lubricant composition comprising at least one base oil for improving the corrosion resistance properties of the lubricant composition, in particular resistance to copper corrosion. It relates to the use of phosphite polymers such as those described herein.

A further subject of the invention is the use of the lubricant composition of the invention for lubricating motor vehicle transmissions, in particular the gears of transmissions. The transmission may be a manual or automatic transmission.

Preferably, the lubricant composition of the present invention is used to reduce wear of mechanical parts of automotive transmissions, particularly gears of automobiles. Thus, in this embodiment, the lubricant composition of the present invention allows for reduced wear of transmission gear units.

Preferably, the lubricant composition of the present invention is used to reduce spalling of mechanical parts of an automobile transmission, particularly of gears in automobiles.

In one advantageous embodiment, the lubricant composition of the present invention is used for both reducing wear and reducing spalling of mechanical parts of automotive transmissions, particularly gears in automobiles.

In another aspect, the present invention further relates to a method for lubricating at least a part of a motor vehicle transmission, in particular a gear unit of a motor vehicle, comprising at least one step of contacting at least said part with a lubricant composition as described above. includes

In another aspect, the present invention further relates to a method for improving the resistance of a lubricant composition to copper corrosion, said method comprising at least one phosphite polymer of formula (I) as defined herein and at least one mixing a boron-containing and/or boron-free dispersant with at least one base oil, preferably said polymer and said dispersant are also further mixed with an antiwear additive as defined herein.

All features and preferences described for the lubricant composition of the present invention and its use also apply to the method.

In the present invention, particular, advantageous or preferred features of the composition of the present invention also allow for the definition of particular, advantageous or preferred uses of the present invention.

The present invention is now described by means of the following examples, which are expressly provided for purposes of illustration and do not limit the invention.

Example

Example 1: Preparation of Lubricant Composition

A lubricant composition was prepared by mixing the ingredients at a temperature of about 40° C. according to methods well known to those skilled in the art. The lubricant compositions prepared and tested are detailed in Table 2 below. Percentages are weight percentages relative to the total weight of the lubricant composition.

The elemental contents of phosphorus, boron and sulfur were calculated as a function of the elemental composition of the elements and are reported in ppm by weight in Table 2.

Finally, the kinematic viscosity at 40 ° C and 100 ° C was determined according to the ASTM D445 method and is listed in Table 2.

CI1 CI2 CI3 CI4 CI5 Base Oil (%) 97.65 97.65 97.65 97.65 97.65 Phosphite polymer (%) 0.5 0.5 0.5 0.5 0.5 Sulfur-phosphorus antiwear agent (%) 0.1 0.1 0.1 0.1 0.1 Boron-containing dispersant (%) 0.5 One Boron-phosphorus dispersant (%) 0.5 One Boron-free dispersant (%) 0.5 Antioxidants (%) 1.0 1.0 1.0 1.0 1.0 Anticorrosive (%) 0.1 0.1 0.1 0.1 0.1 Detergent (%) 0.1 0.1 0.1 0.1 0.1 Antifoam (%) 0.05 0.05 0.05 0.05 0.05 Total (wt.%) 100 100 100 100 100 P content (ppm) 318 318 356 393 318 B content (ppm) 20 40 50 100 0 S content (ppm) 213 213 213 213 213 KV40 (mm ² s) 18.49 18.85 18.43 18.72 18.55 KV100 (mm ² s) 4.09 4.16 4.083 4.127 4.113

In the composition of Table 2:

- the base oil is a Group III base oil;

- the phosphite polymer corresponds to formula (I), contains 4.50% by weight of phosphorus and is free of sulfur, and has a weight average molecular weight of about 10000 g/mol and a number average molecular weight of about 3000 g/mol; This can be obtained, for example, according to the method described in Example 2 of document WO 2011/102861;

- the phosphorus antiwear agent is of the dibutyl phosphite type (not corresponding to formula (I)) and contains 15.80% by weight of phosphorus and no sulfur;

- the sulfur-phosphorus antiwear additive is of the phosphorothionate type and contains 9.30% by weight of phosphorus and 19.80% by weight of sulfur;

- the boron-containing dispersant is a boronated PIBSI containing 0.40% by weight of boron and no phosphorus;

- the boron-phosphorus dispersant is a boronated phosphorylated PIBSI containing 1% by weight of boron and 0.75% by weight of phosphorus;

- the boron-free dispersant is an amine dispersant comprising 3.20% by weight of nitrogen and free of boron and phosphorus;

- the antioxidant is an alkylated diphenylamine antioxidant;

- the anticorrosive agent is tolyltriazine;

- The detergent is an overbased calcium sulfonate detergent.

Example 2: Study of performance of lubricant composition

The corrosion resistance of the lubricant composition shown in Table 2 was tested according to the CEC L-48-00 method with the addition of a copper blade.

By measuring the amount of copper in the lubricant composition at the end of the test, copper corrosion was evaluated after a test time of 168 hours at 150° C., which is shown in Table 3.

The mass of the copper blade was measured before and after a 168 hour test at 150°C. The difference (Δ mass) is shown in Table 3.

CI1 CI2 CI3 CI4 CI5 Copper corrosion (ppm) 16 21 29 46 32 △mass -1.0 -0.3 -1.7 -3.4 -3.1

The results in Table 3 show a very low copper content in the lubricant composition and a small loss of copper blade mass at the end of the test, indicating that the lubricant composition of the present invention exhibits excellent corrosion resistance properties to copper.

Claims (10)

As a lubricant composition,
- at least one base oil,
- at least one dispersant,
- at least one phosphite polymer of formula (I)
and include:
[Formula 1]

here,
- R ¹ , R ² , R ³ and R ⁴ may each independently be selected from the following groups: C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl, C ₆ -C ₄₀ cycloalkyl, C ₇ - C ₄₀ cycloalkenyl _{, C 1-20 methoxy} alkyl glycol ether and Y—OH;
- Y is selected from the following groups: C ₂ -C ₄₀ alkylene, C ₂ -C ₄₀ alkyl lactone, -R ⁷ -N(R ⁸ )-R ⁹ -, wherein R ⁷ , R ⁸ and R ⁹ are each independently selected from hydrogen, C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl _, C ₆ -C ₄₀ cycloalkyl, C ₇ -C ₄₀ cycloalkenyl, C _1-20 methoxy alkyl glycol ether;
- m is an integer from 2 to 100;
- n is an integer from 1 to 1000. According to claim 1,
wherein the polymer of formula (I) has a weight average molecular weight of less than 30000 g/mol. According to claim 1 or 2,
Wherein the phosphite polymer corresponds to 0.01 to 10% by weight of the total weight of the lubricant composition. According to any one of claims 1 to 3,
wherein the dispersant is preferably a boron-containing dispersant selected from boronated and optionally phosphorylated succinimides, preferably selected from boronated and optionally phosphorylated polyisobutylene succinimides. According to any one of claims 1 to 4,
5 to 9150 ppm by weight, preferably 5 to 4500 ppm by weight of phosphorus, based on the total weight of the lubricant composition. According to any one of claims 1 to 5,
at least one antiwear additive selected from phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, phosphorus-amine antiwear additives, sulfur-amine antiwear additives, and mixtures thereof, preferably based on the total weight of the lubricant composition 0.01 to 5% by weight further comprising a lubricant composition. According to any one of claims 1 to 6,
5 to 4000 ppm sulfur by weight, preferably 7 to 1000 ppm sulfur by weight, more preferably 10 to 800 ppm sulfur by weight, based on the total weight of the lubricant composition. According to any one of claims 1 to 7,
With respect to the total weight of the lubricant composition,
- 70 to 99% by weight of one or more base oils, and
- 0.01 to 10% by weight of a phosphite polymer,
- 0.01 to 5% by weight of dispersant(s), preferably comprising at least one boron-containing dispersant,
- optionally, from 0.01 to 5% by weight of antiwear additive(s) selected from phosphorus antiwear additives, sulfur antiwear additives, sulfur-phosphorus antiwear additives, phosphorus-amine antiwear additives, sulfur-amine antiwear additives, and mixtures thereof;
- optionally, from 1 to 30% by weight of one or more functional additives, preferably selected from viscosity index improving additives, antioxidant additives, antifoam additives, boron-free dispersants, detergents, viscosity control additives and mixtures thereof
, Lubricant composition comprising a. Use of a phosphite polymer in combination with a dispersant for improving the corrosion resistance properties of a lubricant composition comprising at least one base oil, said phosphite polymer corresponding to formula (I):
[Formula 1]

here,
- R ¹ , R ² , R ³ and R ⁴ may each independently be selected from the following groups: C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl, C ₆ -C ₄₀ cycloalkyl, C ₇ - C ₄₀ cycloalkenyl _, C _1-20 methoxy alkyl glycol ether and Y—OH (serving as end groups);
- Y is selected from the following groups: C ₂ -C ₄₀ alkylene, C ₂ -C ₄₀ alkyl lactone, -R ⁷ -N(R ⁸ )-R ⁹ -, wherein R ⁷ , R ⁸ and R ⁹ are each independently selected from hydrogen, C ₁ -C ₂₀ alkyl, C ₃ -C ₂₂ alkenyl _, C ₆ -C ₄₀ cycloalkyl, C ₇ -C ₄₀ cycloalkenyl, C _1-20 methoxy alkyl glycol ether;
- m is an integer from 2 to 100;
- n is an integer from 1 to 1000. Use of a composition according to any one of claims 1 to 8, preferably for lubricating at least one mechanical part of a motor vehicle, preferably comprised in a transmission part of a motor vehicle, preferably in a gear unit of a motor vehicle, Usage.