KR102336568B1 - Polyalkylene glycol-based lubricating composition - Google Patents

Abstract

(I)
여기서, R1 및 R2는 동일하거나 상이할 수 있고, 2 내지 7개의 탄소 원자, 바람직하게는 3 내지 6개의 탄소 원자를 포함하는 선형 또는 분지형 2차 알킬기를 독립적으로 나타낸다. 이러한 윤활 조성물은 차량 엔진의, 바람직하게는 원동기 차량의, 윤활에 특히 유용하다.The present application relates to a lubricating composition comprising: an oil selected from polyalkyl glycols (PAG or polyalkylene glycol), and an anti-wear additive selected from compounds of formula (I):

(I)
Here, R1 and R2, which may be the same or different, independently represent a linear or branched secondary alkyl group comprising 2 to 7 carbon atoms, preferably 3 to 6 carbon atoms. Such lubricating compositions are particularly useful for lubrication of motor vehicle engines, preferably prime mover vehicles.

Description

Polyalkylene glycol-based lubricating composition

The present application relates to the field of lubricating compositions, and in particular to the field of lubricating compositions for vehicle engines, in particular for motor vehicle engines. In particular, the present application relates to lubricating compositions based on polyalkylated glycols (PAGs, or polyalkylene glycols) for lubrication of vehicle engines, in particular of prime mover vehicle engines.

There is a growing interest in energy efficiency and reduced fuel consumption of automobile engines. Engine lubricants used in automobiles are known to play an important role in this regard.

Formulating economical fuel lubricants or fuel economizers is known to affect the viscosity of the lubricating base oil used. It is also known to use a polymer which improves the viscosity index (VI), or to use a friction modifier (MF). However, polymers that improve the viscosity index have the disadvantage of lowering the engine cleanliness of the lubricating compositions in which they are used. However, current engines have high thermal stresses that cause significant deposition. The deposits are related to the chemical transformation of the lubricant in the part closest to the combustion chamber (and therefore the hottest part).

A fuel economy lubricating composition based on PAG is described in document WO 2013/164449, which composition also has good properties for engines.

However, the use of these PAGs can sometimes increase the wear of mechanical parts of the engine, and thus can lead to a decrease in the life of the engine.

Accordingly, it is important to provide a lubricating composition for overcoming all or some of the disadvantages of the prior art, in particular a lubricating composition for a prime mover vehicle engine.

It is one object of the present invention to provide lubricating compositions based on PAGs which provide improved wear resistance properties, in particular lubricating compositions based on PAGs for prime mover vehicle engines.

Another object of the present invention is to provide a lubricating composition based on a PAG, in particular a lubricating composition based on a PAG for a prime mover vehicle engine, which provides both improved wear resistance properties and satisfactory fuel economy properties.

Another object of the present invention is to provide a lubricating composition based on PAG, in particular a PAG lubricating composition for prime-motor vehicle engines, which not only provides improved anti-wear properties but also does not degrade engine cleanliness.

Another object of the present invention is to provide a lubricating composition based on PAG, in particular a PAG lubricating composition for a prime mover vehicle engine, which does not degrade engine cleanliness while providing improved wear resistance and satisfactory fuel economy characteristics.

Another object of the present invention is to provide a lubricating composition based on PAG which provides improved wear resistance and is easy to formulate, in particular a lubricating composition based on PAG for motor vehicle engines.

In order to achieve the above object and overcome the disadvantages cited in the prior art, the present invention proposes a lubricating composition comprising:

- oils selected from polyalkyl glycols (PAG or polyalkylene glycols), and

- antiwear additives selected from compounds of formula (I):

(I)

(I)

Here, R1 and R2, which may be the same or different, independently represent a linear or branched secondary alkyl group comprising 2 to 7 carbon atoms, preferably 3 to 6 carbon atoms.

In the context of the present invention, the term "linear or branched secondary alkyl comprising 2 to 7 carbon atoms" is understood to mean an alkyl selected so as to form a secondary alcohol together with the O to which it is attached.

Particularly advantageously, the lubricating composition of the invention is a lubricating composition for an engine, preferably a vehicle, more preferably a prime mover vehicle.

According to the invention, the PAG of the lubricating composition according to the invention may be a block polymer or a random polymer.

The PAG according to the present invention comprises an alkyl group of various lengths of hydrocarbon chains. According to the invention, the length of the hydrocarbon chain is defined by the average value of the number of carbon atoms.

Preferably, the PAG of the composition according to the invention is a block polymer of formula (II) or a random polymer of formula (II):

(II)

(II)

here,

R3 represents a linear or branched C ₁ -C ₃₀ alkyl group, preferably a linear or branched C ₄ -C ₁₂ alkyl group,

n represents a number ranging from 2 to 60, preferably from 5 to 30, or from 7 to 15;

R4 and R5 are the same or different and independently represent a hydrogen atom or a C ₁ -C ₂ alkyl group.

In the case of a PAG according to the invention, n may represent a number in the range from 2 to 60, preferably in the range from 5 to 30, or in the range from 7 to 15.

In a preferred PAG according to the present invention, R3 represents a linear or branched C ₄ -C ₁₂ alkyl group, R4 and R5 are different and independently represent a hydrogen atom or a linear C ₁ -C ₂ alkyl group, and n is 7 to 15 is the number of ranges.

Also preferably, the PAG of the composition according to the invention is a block polymer of formula (IIA) or a random polymer of formula (IIA):

(IIA)

(IIA)

here,

R3 represents a linear or branched C ₁ -C ₃₀ alkyl group, preferably a linear or branched C ₄ -C ₁₂ alkyl group;

m represents a number ranging from 2 to 60, preferably from 5 to 30, or from 7 to 15;

R6 and R7 represent a hydrogen atom, or R6 represents a hydrogen atom and R7 represents a methyl group, or R6 represents a methyl group and R7 represents a hydrogen atom, or R6 and R7 represent a methyl group, or R6 represents an ethyl group and R7 represents a hydrogen atom, or R6 represents a hydrogen atom and R7 represents an ethyl group.

For PAGs according to the invention, m may represent a number in the range from 2 to 60, preferably in the range from 5 to 30, or in the range from 7 to 15.

In a preferred PAG according to the invention, R3 represents a linear or branched C ₄ -C ₁₂ alkyl group, R6 and R7 are different and independently represent a hydrogen atom, a methyl group or an ethyl group, and m represents a number in the range from 7 to 15 indicates.

Also preferably, the PAG of the composition according to the invention is a block polymer of formula (IIB) or a random polymer of formula (IIB):

(IIB)

(IIB)

here,

R3 represents a linear or branched C ₁ -C ₃₀ alkyl group, preferably a linear or branched C ₄ -C ₁₂ alkyl group, more preferably a linear or branched C ₈ -C ₁₂ alkyl group,

p and q independently represent a number ranging from 1 to 30, preferably from 2 to 15, or from 2 to 8;

R8 and R9 represent a hydrogen atom, or R8 represents a hydrogen atom and R9 represents a methyl group, or R8 represents a methyl group and R9 represents a hydrogen atom, or R8 and R9 represent a methyl group, or R8 represents an ethyl group and R9 represents a hydrogen atom, or R8 represents a hydrogen atom and R9 represents an ethyl group,

R10 and R11 represent a hydrogen atom, or R10 represents a hydrogen atom and R11 represents a methyl group, or R10 represents a methyl group and R11 represents a hydrogen atom, or R10 and R11 represent a methyl group, or R10 represents an ethyl group and R11 represents a hydrogen atom, or R10 represents a hydrogen atom and R11 represents an ethyl group.

In the case of a PAG according to the invention, p and q may independently represent a number ranging from 1 to 30, preferably from 2 to 15, or from 2 to 8.

As specific PAGs according to the present invention, the following may be mentioned:

- PAG, wherein R8, R9, R10 and R11 represent a hydrogen atom; or

- PAG in which R8 and R10 represent a hydrogen atom and R9 and R11 represent a methyl group; or

- PAG in which R8 and R10 represent a hydrogen atom and R9 and R11 represent an ethyl group; or

- PAG wherein R8 and R10 represent a hydrogen atom, R9 represents a methyl group and R11 represents an ethyl group; or

- PAG in which R8 and R10 represent a hydrogen atom, R9 represents an ethyl group and R11 represents a methyl group; or

- PAG in which R8, R9 and R11 represent a hydrogen atom and R10 represents a methyl group; or

- PAG wherein R8, R10 and R11 represent a hydrogen atom and R9 represents a methyl group.

In a preferred PAG according to the invention, R3 represents a linear or branched C ₄ -C ₁₂ alkyl group, R8, R10 and R11 represent a hydrogen atom, R9 represents a methyl group, p is a number in the range from 3 to 5, For example, 4.5, q represents a number in the range of 1 to 3, for example, 2.

In a more preferred PAG according to the present invention, R3 represents a linear or branched C ₈ -C ₁₂ alkyl group, R8 represents a hydrogen atom, R9 represents a methyl group, R10 represents a hydrogen atom, R11 represents an ethyl group . p represents a number in the range of 3 to 8, for example 5, and q represents a number in the range of 3 to 8, for example 4.

More preferably, the PAG of the composition according to the invention is a block polymer of formula (III) or a random polymer of formula (III):

(III)

(III)

here,

R3 represents a linear or branched C ₄ -C ₁₂ alkyl group, preferably a linear or branched C ₄ alkyl group,

p represents a number ranging from 1 to 30, preferably from 2 to 15, or from 2 to 8,

q represents a number ranging from 1 to 30, preferably from 1 to 10.

As examples of PAGs of formula (III), mention may be made of the products of ^{the Synalox 50-B ® series sold by Dow Chemical.}

More particularly preferably, the PAG of the composition according to the invention is a block polymer of formula (IV) or a random polymer of formula (IV):

(IV)

(IV)

here,

R3 represents a linear or branched C ₈ -C ₁₂ alkyl group,

p represents a number ranging from 2 to 6,

q represents a number ranging from 2 to 5.

The PAG used in the composition according to the invention may be prepared by the following steps: reacting at least one alcohol type initiator comprising 1 to 30 carbon atoms with an epoxy bond of at least one alkylene oxide; and, then, growing this reaction to obtain these polymers. Preferred alkylene oxides are ethylene oxide, propylene oxide and butylene oxide. A process for preparing a PAG of formula (IV) is described in International Patent Application WO 2012/070007 or International Patent Application WO 2013/164449.

More particularly preferably, the PAG of the composition according to the invention is a block polymer of formula (V) or a random polymer of formula (V):

(V)

(V)

here,

R3 represents a linear or branched C ₄ -C ₁₂ alkyl group, preferably a linear or branched C ₄ alkyl group;

r represents a number ranging from 2 to 60, preferably from 5 to 30, or from 7 to 15.

As examples of PAGs of formula (III), mention may be made of the products of ^{the Synalox 100-B ® series sold by Dow Chemical.}

More preferably, the PAG is a block polymer of formula (VI) or a random polymer of formula (VI):

(VI)

(VI)

here,

R12 represents a linear or branched C ₁ -C ₃₀ alkyl group, preferably a linear or branched C ₈ -C ₁₅ alkyl group;

s and t independently represent an average number ranging from 1 to 5.

For preferred PAGs according to the invention, R12 represents a group selected from: a linear C ₈ alkyl group; branched C ₈ alkyl group; a linear C ₉ alkyl group; branched C ₉ alkyl group; a linear C ₁₀ alkyl group; branched C ₁₀ alkyl; a linear C ₁₁ alkyl group; branched C ₁₁ alkyl group; a linear C ₁₂ alkyl group; branched C ₁₂ alkyl group; a linear C ₁₃ alkyl group; branched C ₁₃ alkyl group; a linear C ₁₄ alkyl group; branched C ₁₄ alkyl group; a linear C ₁₅ alkyl group; branched C ₁₅ alkyl group.

For a preferred PAG according to the invention:

- s is greater than or equal to t; or

- s represents an average number ranging from 2 to 4.5; or

- t represents an average number ranging from 1.5 to 4.

For a preferred PAG according to the invention:

- s represents an average number in the range from 2.5 to 3.5; or

- t represents an average number ranging from 2 to 3.

For a preferred PAG according to the invention:

- s denotes an average number equal to 2.5 and t denotes an average number equal to 2; or

- s denotes an average number equal to 3.5 and t denotes an average number equal to 2.8;

For a preferred PAG according to the invention:

- its kinematic viscosity measured at 100° C. according to ASTM D445 standard is in the range ^{of 2.5 to 4.5 mm 2} .s ^-1; or

- its viscosity index is greater than 160 or from 160 to 210; or

- its pour point is less than -40 °C; or

Its dynamic viscosity (CCS) at -35° C. measured according to ASTM D5293 standard is less than 1,200 mPa·s.

A process for the preparation of PAGs of formula (VI) is described in application WO 2016/016362.

Preferably, the PAG according to the invention comprises at least one butylene oxide unit.

Preferably, the lubricating composition according to the invention comprises 1 to 99.5 wt % of PAG.

Preferably, the lubricating composition according to the invention comprises 1 to 99.5 wt%, preferably 5 to 80 wt%, for example 5 to 70 wt%, 5 to 60 wt%, 5 to 50 wt%, 5 to 40 wt%, preferably 10 to 80 wt%, for example 10 to 70 wt%, 10 to 60 wt%, 10 to 50 wt%, 10 to 40 wt%, preferably 20 to 80 wt%, e.g. for example 20 to 70 wt%, 20 to 60 wt%, 20 to 50 wt%, 20 to 40 wt%, preferably 30 to 80 wt%, for example 30 to 70 wt%, 30 to 60 wt%, 30 to 50 wt %, 30 to 40 wt % of PAG.

More preferably, the lubricating composition according to the invention comprises 1 to 30 wt %, preferably 1 to 20 wt %, more preferably 1 to 15 wt % of PAG.

In another preferred manner, the lubricating composition according to the invention comprises 40 to 99.5 wt%, preferably 50 to 99.5 wt%, more preferably 60 to 99.5 wt%, even more preferably 70 to 99.5 wt%, advantageously contains 80 to 99.5 wt % of PAG.

In addition to the PAG, the lubricating composition according to the invention comprises an antiwear additive selected from the compounds of the formula (I):

(I)

(I)

Here, R1 and R2, which may be the same or different, independently represent a linear or branched secondary alkyl group containing 2 to 7 carbon atoms, preferably 3 to 6 carbon atoms.

In a preferred manner, the antiwear additive is selected from compounds of formula (I):

(I)

(I)

Here, R1 and R2 are the same or different and _{represent a secondary C 3} alkyl group or a secondary C ₆ alkyl group.

More preferably, the groups R1 and R2, which may be the same or different, represent a dimethyl butyl group or an isopropyl group.

Even more preferably, the R1 and R2 groups are the same and represent a dimethyl butyl group or an isopropyl group.

In another more preferred manner, the anti-wear additive comprises a mixture of:

- at least one compound of formula (I) in which R1 represents a secondary C ₃ alkyl group and R2 represents a secondary C _{6 alkyl group,}

- at least one compound of formula (I), wherein R1 and R2 are identical and _{represent a secondary C 6 alkyl group.}

In another even more preferred manner, the anti-wear additive comprises a mixture of:

- at least one compound of formula (I) in which R1 represents a secondary C ₆ alkyl group and R2 represents a secondary C _{3 alkyl group,}

- at least one compound of formula (I), wherein R1 and R2 are identical and _{represent a secondary C 6 alkyl group.}

As an example of a compound of formula (I), mention may be made of the product ^{Lubrizol 1371 ® marketed by Lubrizol.}

Preferably, the lubricating composition according to the invention comprises 0.1 to 3 wt %, preferably 0.1 to 2 wt %, more preferably 0.1 to 1 wt % of the compound of formula (I).

In addition to the PAG and the compound of formula (I), the lubricating composition according to the invention may comprise a base oil.

In general, the lubricating composition according to the present invention may comprise any type of lubricating base oil suitable for its use (mineral, synthetic or natural, animal or vegetable).

Accordingly, the base oil used in the lubricating composition according to the present invention is an oil of mineral or synthetic origin belonging to groups I to V according to the class defined in the API classification (or its equivalent according to the ATIEL classification) (Table 3) , or a mixture thereof.

Preferably, the base oil is different from the PAG.

Saturated content sulfur content Viscosity Index (VI) Group I mineral oils < 90　% > 0,03　% 80 ≤ VI < 120 Group II Hydrocracking Oils ≥ 90　% ≤0,03　% 80 ≤ VI < 120 Group III hydrocracking or hydroisomerized oils ≥ 90　% ≤ 0,03　% ≥ 120 group IV
Polyalphaolefin (PAO) group V esters, and other base oils not included in groups I-IV

Mineral base oils that can be used in the lubricating composition according to the invention include atmospheric and vacuum distillation of crude oil, followed by solvent extraction, desalting, solvent dewaxing, hydrotreating, hydrocracking, hydroisomerization and includes any type of base oil obtained by a refining process such as hydrofinishing. Mixtures of synthetic and mineral oils may also be used.

There are generally no restrictions on the use of the various lubricating base oils for preparing the lubricating compositions according to the invention, provided that they have properties particularly suitable for engine or vehicle transmission (especially viscosity, viscosity index, sulfur content and oxidation resistance). .

The base oil of the lubricating composition according to the invention may also be selected from synthetic oils (eg certain carboxylic acid esters and alcohols), as well as from polyalphaolefins. Polyalphaolefins used as base oil are obtained, for example, from monomers comprising 4 to 32 carbon atoms, for example from octene or decene, and their viscosity at 100° C. is from 1.5 to 15 according to ASTM D445. mm ² .s ^-1 . Their average molecular weight is generally 250 to 3000 according to ASTM D5296.

Advantageously according to the invention, the base oil may be selected from group III oils, group IV oils and group V oils.

Advantageously, the lubricating composition according to the invention may comprise at least 50 wt % of a base oil, based on the total mass of the composition. More advantageously, the lubricating composition according to the invention may comprise at least 60 wt %, or at least 70 wt % of the base oil, based on the total weight of the composition. More particularly advantageously, the lubricating composition according to the invention will comprise 50, 60 or 70 to 99.9 wt %, or 50, 60 or 70 to 90 wt % of one or more base oils, based on the total weight of the composition. can

The lubricating composition according to the invention may also comprise one or more additional additives. Many additional additives can be used in the lubricating composition according to the present invention. Preferred further additives for the lubricating composition according to the invention are selected from detergents, various anti-wear additives from compounds of formula (I), friction modifiers, extreme pressure additives, dispersants, pour point improvers, defoamers, thickeners, and mixtures thereof. .

Preferably, the lubricating composition according to the invention comprises at least one organic friction modifier selected from esters, preferably from mono-esters of polyols, more preferably from glycerol mono-esters. More preferably, the organic friction modifier comprises glycerol and at least 10 carbon atoms, preferably 10 to 20 carbon atoms, more preferably 15 to 20 carbon atoms, advantageously 15 to 18 carbon atoms. glycerol mono-esters obtained by esterification with saturated or unsaturated carboxylic acids.

As examples of organic friction modifiers according to the invention, mention may be made of glycerol mono-oleate.

Preferably, the lubricating composition according to the invention comprises 0.1 to 2 wt %, preferably 0.1 to 1.5 wt %, more preferably 0.5 to 1.5 wt % of organic friction modifier.

There are various other antiwear additives from compounds of formula (I).

Amine phosphates are also antiwear additives that can be used in the lubricating compositions according to the invention. However, the phosphorus provided by these additives can be toxic to the catalytic system of automobiles, since these additives are ash generators. This effect can be minimized by partially replacing the amine phosphate with a non-phosphorus additive, such as a polysulfide, in particular a sulfur containing olefin.

Advantageously, the lubricating composition according to the invention comprises from 0.01 to 6 wt %, preferably from 0.05 to 4 wt %, more preferably from 0.1 to 2 wt % of the anti-wear additive, based on the total weight of the lubricating composition. may include

Lubricating compositions according to the present invention may comprise one or more inorganic friction modifier additives. The inorganic friction modulating additive may be selected from compounds that provide a metallic element, and ash-free compounds. Among the compounds providing a metal element, mention may be made of transition metal complexes such as Mo, Sb, Sn, Fe, Cu and Zn, wherein the ligand of these complexes is a hydrocarbon compound containing oxygen, nitrogen, sulfur or phosphorus can

Advantageously, the lubricating composition according to the invention may comprise at least one antioxidant. Antioxidants generally serve to retard degradation of the lubricating composition during use. Such deterioration can lead, inter alia, to the formation of deposits, the presence of sludge, or an increase in the viscosity of the lubricating composition.

Antioxidants act in particular as radical inhibitors or hydroperoxide scavengers. Among the antioxidants generally used, mention may be made of phenolic antioxidants, amine antioxidants, and antioxidant phospho-sulfur additives. Some of these antioxidants (eg, phospho-sulfur antioxidants) may be ash generators. Phenolic antioxidants may be ash-free or may be in the form of neutral or basic metal salts. The antioxidant may in particular be selected from: hindered phenols, hindered phenol esters and hindered phenols comprising thioether bridges, diphenylamines, diphenyl amines _{substituted with at least one C 1} -C ₁₂ alkyl group, and N,N'-dialkyl-aryl diamines, and mixtures thereof;

Preferably, according to the present invention, hindered phenols are formed in which at least one adjacent carbon of the carbon bearing an alcohol functional group is at least one C ₁ -C ₁₀ alkyl group (preferably a C ₁ -C ₆ alkyl group, preferably C _{4 ).} an alkyl group, preferably a tert-butyl group).

Amino compounds are another class of antioxidants that may be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example aromatic amines of the formula NR ^a R ^b R ^c , wherein R ^a represents an optionally substituted aliphatic or aromatic group, and R ^b is optionally substituted represents an aromatic group, R ^c represents a hydrogen atom, an alkyl group, an aryl group or a group of the formula R ^d S(O) _z R ^e , where R ^d represents an alkylene group or an alkenylene group, and R ^e is an alkyl group, alkenyl This group or an aryl group is represented, and z represents 0, 1 or 2.

Sulfurized alkylphenols or alkali and alkaline earth metal salts thereof may also be used as antioxidants.

Another class of antioxidants are copper compounds (eg copper thio- or dithio-phosphate, copper and carboxylic acid salts, dithiocarbamate, sulfonate, phenate, copper acetylacetonate). Copper salts I and II, succinic acid or anhydride salts may also be used.

The lubricating composition according to the invention may contain antioxidants of all types known to the person skilled in the art.

Also advantageously, the lubricating composition according to the invention comprises from 0.5 to 2 wt % of at least one antioxidant, based on the total weight of the lubricating composition.

The lubricant composition according to the invention may also comprise at least one detergent additive. Detergents generally make it possible to reduce the formation of deposits on the surface of metal parts by dissolving secondary oxidation and combustion products.

Detergents which may be used in the lubricating composition according to the present invention may be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophilic head. The bound cation may be a metal cation of an alkali metal or alkaline earth metal. The detergent is preferably selected from alkali metal or alkaline earth metal salts, sulfonates, salicylates, naphthenates and phenate salts of carboxylic acids. The alkali and alkaline earth metals are preferably calcium, magnesium, sodium or barium. These metal salts generally contain the metal in stoichiometric amounts or in excess (and thus in greater than stoichiometric amounts). Then they are the next overbased detergent additive; Here, the excess metal, which imparts the overbased properties to the detergent, is generally in the form of metal salts that are insoluble in oil (eg carbonates, hydroxides, oxalates, acetates, glutamates, preferably carbonates).

Advantageously, the lubricating composition according to the invention may comprise 2 to 4 wt % of detergent, based on the total weight of the lubricating composition.

Also advantageously, the lubricating composition according to the invention may comprise one or more pour point improvers.

By retarding the formation of paraffin crystals, pour point improvers generally improve the low temperature behavior of the lubricating compositions according to the invention.

As examples of pour point improvers, mention may be made of alkyl polymethacrylates, polyacrylates, polyarylamides, polyalkylphenols, polyalkylnaphthalenes and alkylated polystyrenes.

Advantageously, the lubricating composition according to the invention may also comprise one or more dispersants. The dispersant may be selected from Mannich base, succinimide and derivatives thereof.

Also advantageously, the lubricating composition according to the invention may comprise from 0.2 to 10 wt % of a dispersant, based on the total weight of the lubricating composition.

Advantageously, the lubricating composition may also comprise one or more polymers which improve the viscosity index. Examples of polymers that improve the viscosity index include polymeric esters of styrene, butadiene and isoprene (hydrogenated or unhydrogenated homopolymers or copolymers), polymethacrylates (PMA).

Also advantageously, the lubricating composition according to the invention may comprise 1 to 15 wt %, based on the total weight of the lubricating composition, of a viscosity index improving polymer.

Preferably, the lubricating composition according to the invention is used for lubrication of an engine, preferably a vehicle, more preferably a prime mover vehicle.

Accordingly, the present invention also relates to the use of the lubricating composition according to the invention for lubrication of an engine, preferably a vehicle, more preferably a prime mover vehicle.

More preferably, the present invention also relates to the use of a lubricating composition according to the invention for lubrication of a vehicle engine, more preferably a prime mover vehicle.

The invention also relates to a method for lubricating a prime mover vehicle, preferably a prime mover vehicle, comprising at least one step of contacting the prime mover with a lubricating composition according to the invention.

The present invention also relates to the use of nitrogen compounds of formula (I) for improving the wear resistance of lubricating compositions comprising oils selected from PAGs.

All properties and preferences relating to the compounds of formula (I) and to said PAGs mentioned above apply for this use.

The present invention will now be illustrated using non-limiting examples.

Example 1: Lubricating composition according to the present invention

Lubricating compositions according to the invention are prepared according to Table 1 below (compositions are given by weight (g)).

In the composition:

- PAG 1: PAG comprising a propylene oxide unit and a butylene oxide unit and an OH terminus (corresponding to the formula (IV) of p ≒ 2.8 and q ≒ 2.2)

- PAG 2: PAG comprising a propylene oxide unit and a butylene oxide unit and an -OCH ₃ terminus (corresponding to the formula (VI) with s ≒ 3.5 and t ≒ 2.8)

- antiwear additive 1 (Lubizol 1371 ^® sold by LUBRIZOL): mixture of a compound of formula (I), wherein R1 and R2 are dimethyl butyl groups, and a compound of formula (I), wherein R1 and R2 are isopropyl groups

- antiwear additive 2 (RC3045 ^® sold by RheinChemie): mixture of a compound of formula (I), wherein R1 and R2 are pentyl groups, and a compound of formula (I), wherein R1 and R2 are butyl groups

- Anti-wear additive 3 (KT2203 ^® sold by Kangtai Lubricant Additives): a compound of formula (I) wherein R1 and R2 _{represent a primary C 8 alkyl group}

- Friction modifier 1: glycerol mono-oleate

- Friction modifier 2 (Sakuralube 525 ^® sold by Adeka): molybdenum dithiocarbamate

composition One Comparison 1 Comparison 2 2 3 4 PAG 1 99.5 99.5 99.3 98.5 PAG 2 98.5 99 Anti-Abrasion Additive 1 0.5 0.5 0.5 0.5 Anti-Abrasion Additive 2 0.5 Anti-wear additive 3 0.7 friction modifier 1 One One friction modifier 2 0.5

Example 2: wear resistance evaluation of characteristics

This evaluation is based on a procedure based on the ASTM D2670 standard which requires the use of a FALEX tribometer and the test conditions are described below.

- Specimen: FALEX Steel

- break-in time: 300 seconds

- Trial duration: 180 minutes

- Break-in load: 445 N

- Test load: 1335 N

- Speed: 290 rpm

- ambient temperature

The results are shown in Table 2 and expressed in μm; The lower the obtained value, the better the abrasion resistance properties of the evaluated composition.

composition One Comparison 1 Comparison 2 2 3 4 Total wear (μm) 63 102 136 26 5 11

These results show that the lubricating compositions according to the invention (compositions 1, 2, 3 and 4) have improved wear resistance compared to the comparative lubricating compositions (comparative compositions 1 and 2).

Claims (14)

A composition comprising 80 to 99.5 wt % of an oil selected from a polyalkyl glycol (PAG or polyalkylene glycol), a friction modifier and an anti-wear additive selected from a compound of formula (I)

(I)
(wherein R1 and R2, which may be the same or different, independently represent a linear or branched secondary alkyl group containing 2 to 7 carbon atoms),
The PAG is a block polymer of the following formula (VI) or a random polymer of the following formula (VI),

(VI)
(Where R12 represents a linear or branched C ₁ -C ₃₀ alkyl group, and s and t independently represent an average number ranging from 1 to 5.)
wherein the amount of the anti-wear additive is 0.1 to 3 wt % and the amount of the friction modifier is 0.1 to 2 wt %. The composition of claim 1 , wherein the anti-wear additive is selected from compounds of formula (I):

(I)
Here, R1 and R2 are the same or different and _{represent a secondary C 3} alkyl group or a secondary C ₆ alkyl group. 3. Composition according to claim 1 or 2, comprising 0.1 to 2 wt % of said compound of formula (I). 3. A composition according to claim 1 or 2 comprising a lubricating base. 3. A composition according to claim 1 or 2, wherein said friction modifier is selected from esters. A method for lubricating a vehicle engine comprising the step of contacting the composition according to claim 1 or 2 with the vehicle engine. delete delete delete delete delete delete delete delete