EP4662295A1

EP4662295A1 - Use of a composition as friction coefficient reducer in an oil based lubricating composition for engines and transmissions without clutch, and new synergistic compositions

Info

Publication number: EP4662295A1
Application number: EP24704003.3A
Authority: EP
Inventors: Christelle Florence CHRETIEN; Guillaume GODY; Marie-Pierre Labeau
Original assignee: Specialty Operations France SAS
Current assignee: Specialty Operations France SAS
Priority date: 2023-02-09
Filing date: 2024-02-08
Publication date: 2025-12-17
Also published as: CN120659861A; WO2024165689A1; EP4662296A1; CN120677221A; WO2024165688A1

Abstract

The instant invention concerns the use of a composition comprising polymer P obtained by radical copolymerization of a mixture of (i) at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom; (ii) at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and (iii) at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; as friction coefficient reducer in an oil based lubricating composition for engines and transmissions without clutch.

Description

USE OF A COMPOSITION AS FRICTION COEFFICIENT REDUCER IN AN OIL BASED LUBRICATING COMPOSITION FOR ENGINES AND TRANSMISSIONS WITHOUT CLUTCH, AND NEW SYNERGISTIC COMPOSITIONS

This application claims priority to the applications respectively filed on February 9, 2023 in the USA with No. SN63/483990, on March 6, 2023 in Europe with No. 23160107.1 , and on September 29, 2023 in Europe with No. 23201073.6 the whole content of each of these applications being incorporated herein by reference for all purposes.

This invention relates to the field of lubricating compositions for engines and transmissions without clutch (such as gears), in particular the need for those compositions to have a low friction coefficient in this application. It concerns specifically the use of a composition comprising a specific polymer, advantageously in combination with a friction modifier for lowering the friction coefficient of an oil based lubricating composition for engine and transmissions without clutch.

BACKGROUND ART

In several mechanical domains (automotive or industrial applications), and in particular as soon as metal parts are put in repeated contact, there is a need to reduce the friction at the surface and to limit the wear of said metallic parts, notably by the use of lubricating compositions. In the field of lubricating compositions, we can distinguish two different applications. The first ones are the applications for which a low friction coefficient is targeted, which is typically the case of lubricating compositions for engines and transmissions without clutch. The second ones are the ones that on the contrary require a high friction coefficient, like in power transmissions containing clutch.

Some additives are included in those lubricating compositions which substantially contain a base oil, depending on the targeted application and desired effect.

To reach a high friction coefficient (above 0.1) in the applications that require such a behavior, several compounds, among which polymers are described, notably in US2006/105924.

To lower the friction coefficient of lubricating compositions (below 0.1), it is commonly known to use some friction modifiers.

Traditional friction modifiers are either: organic friction modifiers (OFMs) that include partial esters and fatty amides such as glycerol mono-oleate and oleyl amide. OFMs typically have a polar head-group which enables the OFM to adsorb onto the metal surface, and a non-polar hydrocarbon backbone which is required to maintain oil solubility and to enable film formation between contacting surfaces.

Inorganic friction modifiers (IFMs) which contain non-organic elements, such as sulphur, phosphorus and molybdenum. Inorganic IFMs chemically break down to form products able to chemisorb or physisorb onto metal surfaces, forming low shear strength films. An example of an inorganic friction modifier that is widely used in Japanese engine oils in particular is molybdenum dithiocarbamate (MoDTC).

Some patents propose to lower the coefficient of friction by associating different friction modifiers: US2013/0274158, US2013/0244915, and FR3014898.

However, it is known to a person skilled in the art that the use of friction modifiers, in particular of organomolybdenum compounds comprising a dithiocarbamate group, can cause worsening of the phenomena of wear of mechanical parts. Thus, in order to solve this problem, anti-wear compounds can be added.

Standard anti-wears are either based on SAPS (Sulfated Ash, Phosphorus, Sulfur) technology like ZDDP (Zinc DialkylDithioPhosphate) or based on phosphorus chemistry (typically Phosphate esters, or phosphites). Both technologies provide either ash, sulfur and/or a high level of phosphorus content.

ZDDP has a good performance but for environmental reasons, there is a need to decrease of the use of anti-wear containing metal, sulfur and phosphorus because: metals are detrimental to lubricants as they produce ash when burnt and build up deposits on surfaces. Varnish and deposits are detrimental to mechanical equipment impacting its durability and especially in electric vehicle driveline units in which a good thermal conductivity is needed.

Sulfur induces corrosion especially on copper materials. Copper is used in alloys in engines and this material is extensively used in electric vehicles driveline units as electrical wires are present.

Used in engine oils, sulfur and phosphorus poison the activity of catalysts present in catalytic convertors which get deactivated.

To overcome the above issues, polymeric anti-wears (AW) have been developed, for example as described in WO2016/177839. The polymeric AW presents the advantage of being ashless (no metal), having no sulfur and a very low P level (typically around 0.34% vs. 8% of P in ZDDP). In this document, the use of this polymeric anti-wear in a naphthenic oil has been described but there are some limitations in terms of solubility with other base oils used for engines and transmissions without clutch.

Polymers, in particular based on acrylate monomers, have also been described as viscosity index improvers in lubricating compositions, which is a very different and unrelated function from anti-wear property.

In this context, there is still a need to develop new environment-friendly solutions for a good performance in both reduction of the friction of the lubricating compositions for engines and transmissions without clutch, and protecting against wear of the metallic parts that are in repeated contact. In addition, the solution found should be easily soluble in common base oils for engines and transmissions without clutch.

BRIEF DESCRIPTION

While performing research in order to address the above technical problem, the inventors have surprisingly discovered that a composition comprising at least one polymer P obtained by radical copolymerization of a mixture comprising: at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom;

- at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and

- at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; is able to lower the friction coefficient of an oil based lubricating composition for engine or transmission without clutch. Said composition is also a good anti-wear agent.

Hence, a first object of the present invention is the use of a composition comprising at least one polymer P obtained by radical copolymerization of a mixture comprising : at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom; at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; as friction coefficient reducer agent in oil-based lubricating compositions for engines and transmissions without clutch, preferably as both anti-wear agent and friction coefficient reducer agent in oil-based lubricating compositions for engines and transmissions without clutch.

In addition, the inventors have found that combining the above polymer P with a friction modifier is boosting the effect of lowering the friction coefficient of an oil based lubricating composition for engine. Hence, as second object of the present invention, the invention aims at a synergistic composition comprising:

• at least one polymer P obtained by radical copolymerization of a mixture comprising: at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom;

- at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; and

• at least one friction modifier agent FM selected from the group consisting of organomolybdenum friction modifiers such as molybdenum dialkyl dithiocarbamates and molybdenum dialkyl dithiophosphates, and organic friction modifiers such as glycerol esters, fatty amides and fatty amines, preferably molybdenum dithiocarbamate and glycerol monooleate.

A third object of the present invention is a synergistic oil based lubricant composition for engines comprising:

• at least a base oil and

• a synergistic composition as defined above.

In the above composition and synergistic composition, the polymer is preferably a polymer P obtained by radical copolymerization of a mixture comprising: at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom; at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and at least one monomer M2’ being a C11-C30 alkyl acrylate and at least one monomer M2” being a C11-C30 alkyl methacrylate.

A fourth object of the present invention is a hence polymer P obtained by radical copolymerization of a mixture comprising: at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom; at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and at least one monomer M2’ being a C11-C30 alkyl acrylate and at least one monomer M2” being a C11-C30 alkyl methacrylate.

This polymer id advantageously obtained by radical copolymerization of a mixture consisting essentially of monomers P1 , M1 , M2’ and M2”.

This polymer P is most advantageously obtained by radical copolymerization of a mixture consisting essentially of:

- vinylphosphonic acid;

- 2-ethylhexyl acrylate;

- dodecyl acrylate and

- dodecyl methacrylate.

DEFINITION

Before the issues of the invention are described in detail, the following should be considered:

As used herein, the singular forms "a", "an", and "the" include both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compound" means one compound or more than one compound.

The terms "comprising", "comprises" and "comprised of" as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. It will be appreciated that the terms "comprising", "comprises" and "comprised of" as used herein comprise the terms "consisting of", "consists" and "consists of".

Throughout this application, the term "about" is used to indicate that a value includes the standard deviation of error for the device or method being employed to determine the value. As used herein, the term "average" refers to number average unless indicated otherwise. As used herein, the terms "% by weight", "wt.- %", "weight percentage", or "percentage by weight", and the terms "% by volume", "vol.- %", "volume percentage", or "percentage by volume", are used interchangeably.

The recitation of numerical ranges by end points includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1 , 2, 3, 4 when referring to, for example, a number of elements, and can also include 1 .5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein. The term "alkyl" refers to a straight or branched chain monovalent hydrocarbon radical having a specified number of carbon atoms. Alkyl groups may be unsubstituted or substituted with substituents that do not interfere with the specified function of the composition and may be substituted once or twice with the same or different group. Substituents may include alkoxy, hydroxy, mercapto, amino, alkyl substituted amino, nitro, carboxy, carbonyl, carbonyloxy, cyano, methylsulfonylamino, or halogen, for example. Examples of "alkyl" include, but are not limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, n-hexyl, 3-methylpentyl, and the like.

As used herein, the term “alkenyl” is defined identically as “alkyl” except for containing at least one carbon-carbon double bond, and having notably two to thirty carbon atoms, for example, two to twenty carbon atoms, or two to ten carbon atoms. Specifically contemplated alkenyl groups include ethenyl, 1 -propenyl, 2-propenyl, and butenyl. Unless otherwise indicated, an alkenyl group can be an unsubstituted alkenyl group or a substituted alkenyl group.

As used herein, the term “alkynyl” is defined identically as “alkyl” except for containing at least one carbon-carbon triple bond, and having notably two to thirty carbon atoms, for example, two to twenty carbon atoms, or two to ten carbon atoms. Specifically contemplated alkynyl groups include ethynyl, 1-propynyl, 2-propynyl, and butynyl. Unless otherwise indicated, an alkynyl group can be an unsubstituted alkynyl group or a substituted alkynyl group.

As used herein, the term “acrylate” corresponds to salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion CH2=CH-COO-.

DETAILED DESCRIPTION

POLYMER P

Advantageously, the monomer P1 of the polymer P used in the present invention is selected from the group consisting of: phosphonic acid monomers, phosphoric acid monomers, dioxaphospholane monomers, phosphonic acid (meth)acrylate and (meth)acrylamido monomers, phosphoric acid (meth)acrylate and (meth)acrylamido monomers, and monomers comprising 2 phosphorus atoms like 2-[2,2- bis(diisopropoxyphosphoryl)ethoxy]methyl methacrylate and propyl N,N- tetramethylbis(phosphonate)-2-hydroxybismethylamine methyl methacrylate.

Phosphonic acid monomers P1 of the polymer P may be for instance compounds of formula (I) where

R1 = H, a C1-C4 alkyl or a group where R = H or C-C4 alkyl, preferably ethyl, (t)butyl R2 = H or a C1-C4 alkyl, preferably methyl, ethyl or (i)propyl

X = a single bond or a spacer chosen from a C1-C4 alkyl, ether or ketone, preferably from -CH2-, -CH2-CH2-, -CH2-O-CH2-CH2, -CH2-O-CO-CH2-, -CH2-O-(CH2)n-, -O-(CH2)n- wherein n = 1 or 2.

Phosphonic acid monomers which can be used in the frame of the invention are those of the following formula: A or Isopropenyl Phosphonic Acid) r Vinyl Phosphonic Acid).

Still other phosphonic acid monomers which can be used in the frame of the invention are diallyl aminophosphonic acids and esters/salts thereof, preferably diallyl aminomethylphosphonic acids and esters/salts thereof, preferably those having the following formula:

where R² is as defined above. Phosphoric acid monomers P1 of the polymer P may be for instance compounds of formula (II) where R1 and R2 are as defined above and where X is a single bond or a spacer chosen from a C1-C4 alkyl or ether eventually bearing hydroxyl and/or phosphate group(s) (PO4H2), preferably from -CH2-, -CH2-CH2-, -O-(CH2)4-, -O-CH2-CHOH-CH2-, -CH2-O-

CH2-CHOH-CH2-, -O-CH2-C(PO4H2)-CH2-, -CH2-O-CH2-C(PO4H2)-CH2-. Dioxaphospholane monomers P1 of the polymer P may be for instance compounds of formula (III): where X is a spacer chosen from C1-C4 ethers, preferably from -O-CH2 or -CH2-O-CH2.

Phosphonic acid (meth)acrylate and (meth)acrylamido monomers P1 of the polymer P may be for instance compounds of formula (IV) where R1 = H or CH3, X = -O-, -NH- or -N(CH3)-, R2 is as defined above and Y is a spacer chosen from C1-C10 alkyl or ether or thioether eventually bearing hydroxyl and or phenyl group (Ph), preferably -CH2-CH2-, -C(CH3)2-CH2-CH2-CH2-, -(CH2-CH2)3-O-CH2-CH2- , -CH2-CHOH-CH2-O-CO-CH2-, -CH2-Ph-CH2-, CH2-CHOH-CH2-S-Ph-, CH2-CHOH- CH2-O-Ph-.

Phosphoric acid (meth)acrylate and (meth)acrylamido monomers P1 of the polymer P may be for instance compounds of formula (V) where R1 = H or CH3, X = -O-, -NH- or -N(CH3)-, R2 is as defined above and Y is a spacer chosen from C1-C10 alkyl or alkylene oxide units, preferably ethylene oxide and/or propylene oxide units, -CH2-CH2-.

Phosphoric acid (meth)acrylate and (meth)acrylamido monomers which have been tested in the frame of the invention are those of the following formula: wherein p is from 1 to 2 wherein n is from 3 to 9.

We can also consider PO/EO monomers containing P like the ones of the following formula: wherein m+n is at most equal to 15, preferably 10; and when n = 0: m = 1 5, preferably 1-3; and when n > 0: n > m+2.

Preferably the monomer P1 of the polymer P is vinyl phosphonic acid (VPA).

Advantageously, the monomer M1 of the polymer P used in the present invention is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n- propyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, iso-hexyl (meth)acrylate, n- heptyl (meth)acrylate, iso-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2- ethylhexyl (meth)acrylate, iso-octyl (meth)acrylate, n-nonyl (meth)acrylate, preferably 2- ethylhexyl (meth)acrylate.

Regarding the monomer M2, it is advantageously selected from the group consisting of n- undecyl (meth)acrylate, iso-undecyl (meth)acrylate, iso-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, n-octadecyl (meth)acrylate, n-nonadecyl (meth)acrylate, dodecyl (meth)acrylate, n-eicosyl (meth)acrylate, and n-tricosyl (meth)acrylate, preferably dodecyl acrylate and dodecyl methacrylate.

In a preferred embodiment, the polymer P comprises at least one monomer M2’ being a C11-C30 alkyl acrylate and at least one monomer M2” being a C11-C30 alkyl methacrylate, more preferably dodecyl acrylate and dodecyl methacrylate.

In a preferred embodiment, the polymer P is obtained by radical copolymerization of a mixture consisting essentially of:

- vinylphosphonic acid;

- 2-ethylhexyl acrylate;

- dodecyl acrylate and

- dodecyl methacrylate.

More preferably, the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of vinylphosphonic acid, 2-ethylhexyl acrylate, dodecyl acrylate and dodecyl methacrylate:

- vinylphosphonic acid: from 1 to 20%, notably from 2 to 15%, preferably from 5 to 10%;

- 2-ethylhexyl acrylate: from 10 to 90%, notably from 20 to 80%, preferably from 30 to 60%;

- dodecyl acrylate: from 10 to 70%, notably from 15 to 50% and more preferably from 20 to 40%;

- dodecyl methacrylate: from 10 to 70%, notably from 15 to 50% and more preferably from 20 to 40%.

Even more preferably, the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of vinylphosphonic acid, 2- ethylhexyl acrylate, dodecyl acrylate and dodecyl methacrylate: - vinylphosphonic acid: from 1 to 20%, notably from 2 to 15%, preferably from 5 to 10%;

- 2-ethylhexyl acrylate: from 30 to 60%;

- dodecyl acrylate: from 15 to 50%, preferably from 20 to 40%;

- dodecyl methacrylate: from 15 to 50%, preferably from 20 to 40%.

COMPOSITION

According a preferred embodiment, the use according to the invention is such that the composition is further comprising at least one friction modifier agent FM selected from the group consisting of organomolybdenum friction modifiers such as molybdenum dialkyl dithiocarbamates and molybdenum dialkyl dithiophosphate, and organic friction modifiers such as glycerol esters, fatty amides and fatty amines, preferably molybdenum dithiocarbamate and glycerol monooleate. Indeed, as shown in the experimental part below, the effect on the reduction of the friction coefficient is boosted when at least one FM as described above is in combination with the composition of the present invention.

Advantageously, the composition is comprising from 0.1 to 10% by weight, preferably from 0.5 to 2.5% by weight, based on the total weight of the composition, of the friction modifier agent FM as described above.

According to a preferred embodiment, the oil based lubricating composition in which the composition according to the invention is used comprises a base oil that is selected in the group consisting of mineral oils, synthetic oils and natural oils.

Mineral oils are known per se and commercially available. They are generally obtained from mineral oil or crude oil by distillation and/or refining and optionally further purification and finishing processes, the term mineral oil including in particular the higher-boiling fractions of crude or mineral oil. In general, the boiling point of mineral oil is higher than 200°C, preferably higher than 300°C, at 5000 Pa. The production by low- temperature carbonization of shale oil, coking of bituminous coal, distillation of brown coal with exclusion of air, and also hydrogenation of bituminous or brown coal is likewise possible. Accordingly, mineral oils have, depending on their origin, different proportions of aromatic, cyclic, branched and linear hydrocarbons.

Synthetic oils include organic esters, for example diesters and polyesters, polyalkylene glycols, polyethers, synthetic hydrocarbons, especially polyolefins, among which preference is given to polyalphaolefins (PAOs), silicone oils and perfluoroalkyl ethers. In addition, it is possible to use synthetic base oils originating from gas to liquid (GTL), coal to liquid (CTL) or biomass to liquid (BTL) processes. They are usually somewhat more expensive than the mineral oils, but have advantages with regard to their performance.

Natural oils are animal or vegetable oils, for example neatsfoot oils or jojoba oils.

Base oils for lubricant oil formulations are divided into groups according to API (American Petroleum Institute). Mineral oils are divided into group I (non-hydrogen-treated) and, depending on the degree of saturation, sulfur content and viscosity index, into groups II and III (both hydrogen-treated). PAOs correspond to group IV. All other base oils are encompassed in group V.

These base oils usable in the present invention may also be used as mixtures and are in many cases commercially available.

According to a preferred embodiment, the base oil is a mineral oil of group II or III or a synthetic base oil, notably a group IV synthetic base oil, or a mixture thereof.

FRICTION REDUCTION EFFECT

According to the use of the present invention, the friction coefficient of the oil based lubricant composition is reduced to an absolute value below 0.2 between 40 and 150°C measured using HFRR (High Frequency Reciprocating Rig) tribology test according to ASTM D6079, except for the diesel fuel which has been replaced by the oil based lubricant composition and the constant time and temperature of 60°C for 75 min has been replaced by a warmup phase at 40°C for 15 min and a ramp-up phase up to 150°C with 2°C/min for 55 min.

Preferably, the friction coefficient of the oil based lubricant composition is lowered of 0.12 point compared to an oil based lubricant composition consisting in base oil only, between 70 and 150°C measured using HFRR (High Frequency Reciprocating Rig) tribology test according to ASTM D6079, except for the diesel fuel which has been replaced by the oil based lubricant composition and the constant time and temperature of 60°C for 75 min has been replaced by a warm-up phase at 40°C for 15 min and a ramp-up phase up to 150°C with 2°C/min for 55 min.

SYNERGISTIC COMPOSITION

The second object of the present invention is a synergistic composition comprising:

• at least one polymer P obtained by radical copolymerization of a mixture comprising:

- at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom;

-at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and -at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; and • at least one friction modifier agent FM selected from the group consisting of organomolybdenum friction modifiers such as molybdenum dialkyl dithiocarbamates and molybdenum dialkyl dithiophosphate, and organic friction modifiers such as glycerol esters, fatty amides and fatty amines, preferably molybdenum dithiocarbamate and glycerol monooleate.

In this synergistic composition, preferred organomolybdenum friction modifiers are indeed molybdenum dialkyl dithiocarbamates and molybdenum dialkyl dithiophosphate and preferred organic friction modifiers are indeed glycerol esters, fatty amides and fatty amines. Said synergistic composition preferably consists essentially of at least one polymer P obtained by radical copolymerization of a mixture consisting essentially of: at least one ethylenically unsaturated monomer P1 containing at least one phosphorus atom;

- at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and

- at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; and at least one friction modifier agent FM selected from the group consisting of molybdenum dithiocarbamate and glyceryl monooleate.

Preferably, the polymer P comprises at least one monomer M2’ and at least one monomer M2” as defined above.

In said synergistic composition according to the invention, the polymer P is advantageously obtained by radical copolymerization of a mixture consisting essentially of:

- vinylphosphonic acid;

- 2-ethylhexyl acrylate;

- dodecyl acrylate and

- dodecyl methacrylate.

In a preferred embodiment, the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of vinylphosphonic acid, 2-ethylhexyl acrylate, dodecyl acrylate and dodecyl methacrylate:

- dodecyl acrylate: from 10 to 70%, notably from 15 to 50% and more preferably from 20 to 40%; dodecyl methacrylate: from 10 to 70%, notably from 15 to 50% and more preferably from 20 to 40%.

Even more preferably, the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of vinylphosphonic acid, 2- ethylhexyl acrylate, dodecyl acrylate and dodecyl methacrylate:

- 2-ethylhexyl acrylate: from 30 to 60%; dodecyl acrylate: from 15 to 50%, preferably from 20 to 40%; dodecyl methacrylate: from 15 to 50%, preferably from 20 to 40%.

In an advantageous embodiment of the synergistic composition according to the invention, the composition comprises from 0.1 to 10% by weight, preferably from 0.5 to 2.5% by weight, based on the total weight of the composition, of at least one friction modifier agent FM.

The most impressive results are obtained with the synergistic composition according to the invention wherein the friction modifier is glyceryl monooleate (GMO). The effect on reduction of the friction coefficient is surprisingly high.

SYNERGISTIC OIL BASED LUBRICANT COMPOSITION

The third object of the present invention is a synergistic oil based lubricant composition for engines and transmissions without clutch comprising:

• at least a base oil and

• the synergistic composition as defined previously.

In a preferred embodiment, the synergistic lubricant oil composition for engines and transmissions without clutch according to the invention is such that the base oil is a mineral oil of group II or III or a synthetic base oil, notably a group IV synthetic base oil, or a mixture thereof.

According to the invention, the concentration of the polymer P in the oil based lubricant composition is preferably in the range of 0.01 to 10% by weight, more preferably in the range of 0.1 to 5% by weight and most preferably in the range of 0.5 to 2.5% by weight, based on the total weight of the oil based lubricant composition.

The composition comprising the polymer P according to the invention can be mixed with the base oil(s).

The composition comprising the polymer P according to the invention may be added to a fresh oil and/or to an aged oil. Furthermore, the composition comprising the polymer P according to the invention can be added directly in the engine and transmission without clutch oil or indirectly through dilution effect using a diesel mixture comprising the polymers. In addition to the composition comprising the polymer P according to the invention, the oil based lubricant compositions may also comprise further additives. These additives include viscosity index improvers, pour point improvers and DI additives (dispersants, detergents, defoamers, corrosion inhibitors, antioxidants, other antiwear and extreme pressure additives, other friction modifiers).

The additionally usable VI improvers include poly(iso)butenes (PIB), fumarate-olefin copolymers, styrene-maleate copolymers, hydrogenated styrene-diene copolymers (HSD) and olefin copolymers (OCP) and polymethacylates.

Appropriate dispersants include poly(isobutylene) derivatives, e.g. poly(isobutylene) succinimides (PIBSIs); polyisobutenyl succinic anhydride (PIBSA), polyisobutenyl succinimide, polyisobutenyl succinate ester, polyaminomethylalkylphenol (also called Mannich dispersants).

The preferred detergents include metal-containing compounds, for example phenoxides; salicylates; thio-phosphonates, especially thiopyrophosphonates, thio-phosphonates and phosphonates; sulfonates and carbonates. As metals, these compounds may comprise especially calcium, magnesium and barium. These compounds may be used preferably in neutral or overbased form.

Of particular interest are additionally defoamers, which are in many cases divided into silicone-containing and silicone-free defoamers. The silicone-containing defoamers include linear poly(dimethylsiloxane) and cyclic poly(dimethylsiloxane). The silicone-free defoamers which may be used are in many cases polyacrylates and polyethers, for example poly(ethylene glycol) or tributyl phosphate.

In a particular embodiment, the inventive lubricant oil compositions may comprise corrosion inhibitors. These are in many cases divided into antirust additives and metal passivators/deactivators. The antirust additives used may, inter alia, be sulfonates, for example petroleumsulfonates or (in many cases overbased) synthetic alkylbenzenesulfonates, e.g. dinonylnaphthenesulfonates; carboxylic acid derivatives, for example lanolin (wool fat), oxidized paraffins, zinc naphthenates, alkylated succinic acids, 4-nonylphenoxy-acetic acid, amides and imides (/V-acylsarcosine, imidazoline derivatives); amine-neutralized mono- and dialkyl phosphates; morpholine, dicyclohexylamine or diethanolamine. The metal passivators/deactivators include benzotriazole, tolyltriazole, 2- mercaptobenzothiazole, dialkyl-2, 5-dimercapto-1 , 3,4-thiadiazole; N, N -disalicylidene ethylenediamine, N, /V'-disalicylidenepropylenediamine; zinc dialkyldithiophosphates and dialkyl dithiocarbamates.

A further preferred group of additives is that of antioxidants. The antioxidants include, for example, phenols, for example 2, 6-di-tert-butylphenol (2,6-DTB), butylated hydroxytoluene (BHT), 2,6-di-tert-butyl-4-methylphenol, 4, 4'-methylenebis(2, 6-di-tert-butylphenol); aromatic amines, especially alkylated diphenylamines, /V-phenyl-1 -naphthylamine (PNA), polymeric 2,2,4-trimethyldihydroquinone (TMQ); compounds containing sulfur and phosphorus, for example metal dithiophosphates, e.g. zinc dithiophosphates (ZnDTP), "OOS triesters", reaction products of dithiophosphoric acid with activated double bonds from olefins, cyclopentadiene, norbornadiene, u-pinene, polybutene, acrylic esters, maleic esters (ashless on combustion); organosulfur compounds, for example dialkyl sulfides, diaryl sulfides, polysulfides, modified thiols, thiophene derivatives, xanthates, thioglycols, thioaldehydes, sulfur containing carboxylic acids; heterocyclic sulfur/nitrogen compounds, especially dialkyldimercaptothiadiazoles, 2-mercaptobenzimidazoles; zinc and methylene bis(dialkyldithiocarbamate); organophosphorus compounds, for example triaryl and trialkyl phosphites; organocopper compounds and overbased calcium- and magnesium-based phenolates and salicylates.

As potential other preferred antiwear (AW) and extreme pressure (EP) additives include phosphorus compounds, for example trialkyl phosphates, triaryl phosphates, e.g. tricresyl phosphate, amine-neutralized mono- and dialkyl phosphates, ethoxylated mono- and dialkyl phosphates, phosphites, phosphonates, phosphines; compounds containing sulfur and phosphorus, for example metal dithiophosphates, e.g. zinc dialkyl dithiophosphates (ZnDTPs), ammonium dialkyldithiophosphate, antimony dialkyldithiophosphates, molybdenum dialkyldithiophosphates, lead dialkyldithiophosphates, "OOS triesters' -reaction products of dithiophosphoric acid with activated double bonds from olefins, cyclopentadiene, norbornadiene, u-pinene, polybutene, acrylic esters, maleic esters, triphenylphosphorothionate (TPPT); compounds containing sulfur and nitrogen, for example zinc bis(amyl dithiocarbamate) or methylenebis(di-n-butyl dithiocarbamate); sulfur compounds containing elemental sulfur and H~S-sulfurized hydrocarbons (diisobutylene, terpene); sulfurized glycerides and fatty acid esters; overbased sulfonates; chlorine compounds or solids such as graphite or molybdenum disulfide.

More preferably, if any, the other antiwear additive and/or extreme pressure additive is selected from phosphorus compounds, compounds comprising sulfur and phosphorus, compounds comprising sulfur and nitrogen, sulfur compounds comprising elemental sulfur and H~S-sulfurized hydrocarbons, sulfurized glycerides and fatty acid esters, overbased sulfonates, chlorine compounds, graphite or molybdenum disulfide.

A further preferred group of additives is that of additional friction modifiers. The additional friction modifiers used may include mechanically active compounds, for example molybdenum disulfide, graphite (including fluorinated graphite), poly(tri-fluoroethylene), polyamide, polyimide; compounds which form adsorption layers, for example long-chain carboxylic acids, fatty acid esters, ethers, alcohols, amines, amides, imides; compounds which form layers through tribochemical reactions, for example saturated fatty acids, phosphoric acid and thiophosphoric esters, xanthogenates, sulfurized fatty acids; compounds which form polymer-like layers, for example ethoxylated dicarboxylic acid partial esters, dialkylphthalates, methacrylates, unsaturated fatty acids, sulfurized olefins or organometallic compounds, for example molybdenum compounds (molybdenum dithiophosphates and molybdenum dithiocarbamates MoDTC) and their combinations with ZnDTPs, copper-containing organic compounds.

Some of the additives detailed above may fulfill multiple functions.

The lubricant useful for the present invention, especially for engine oils, can preferably be designed to meet the requirements of the SAE classifications as specified in SAE J300. E.g. the requirements of the viscosity grades 0W, 5W, 10W, 15W, 20W, 25W, 20, 30, 40, 50, and 60 (single-grade) and 0W-40, 10W-30, 10W-60, 15W-40, 20W-20 and 20W-50 (multigrade) could be adjusted.

The present invention also concerns the use of a composition comprising at least one polymer P as described above: as polymeric anti-wear and friction modifier in lubricants (including but not limited to engines, transmissions, hydraulic systems); and/or in metalworking fluids (including but not limited to forming fluids and removing fluids) and/or in greases (including but not limited to bearings, gears, wire ropes); or as an adhesion promoter and/or additive providing corrosion resistance, namely in the adhesive bonding of two surfaces, for bonding a paint or varnish or ink to a metallic surface, or as an additive in coating compositions.

POLYMERIC ANTI-WEAR (AW) AND ITS USE IN LUBRICANT COMPOSITIONS

In several mechanical domains (automotive or industrial applications), and in particular as soon as metal parts are put in repeated contact, there is a need to reduce the friction at the surface and to limit the wear of said metallic parts, notably by the use of lubricating compositions. Some additives, including anti-wear additives are included in those lubricating compositions which substantially contain a base oil, depending on the targeted application and desired effect.

Standard anti-wears are either based on SAPS (Sulfated Ash, Phosphorus, Sulfur) technology like ZDDP (Zinc DialkylDithioPhosphate) or based on phosphorus chemistry (typically Phosphate esters, phosphonates or phosphites). Both technologies provide either ash, sulfur and/or a high level of phosphorus content. To overcome the issues with the presence of SAPS, polymeric anti-wears (AW) have been developed. The polymeric AW presents the advantage of being ashless (no metal), having no sulfur and a very low P level.

The developed Polymeric Anti-Wear composition typically presents composition comprising at least one polymer P as described above.

By combining polymeric AW with a friction modifier, it is possible to boost the effect of lowering the friction coefficient of an oil based lubricating composition.

Polymeric AW can be used in Lubricants for any type of application that requires AW additives, like in industrial or automotive applications, including but not limited to Lubricants for Industrial uses (as example, hydraulic fluids, compressor fluids, refrigeration oils, turbine and circulating oils, gear oils, other gear industrial oils, industrial engine oils, metalworking fluids and greases) and/or Automotive Lubricants (as example, engine oils, transmission fluids, coolants and greases).

USE AS ADHESION PROMOTER AND/OR ADDITIVE PROVIDING CORROSION RESISTANCE

The polymer P as described above can also be used as adhesion promoter in several applications listed below.

In a first embodiment, the copolymer can be used in adhesive bonding of two surfaces S1 and S2, preferably metallic ones, to each other. The idea is to use the copolymer in a surface treatment composition for all or parts of the (preferably metallic) surface (S1) and optionally all or parts of the (preferably metallic) surface (S2) and/or as additive in the adhesive layer between both surfaces. In this process, the surface treatment composition may be: a conversion composition ; and/or a solution or a dispersion applied on the surface after having applied a conversion coating on the surface to be treated. In a second embodiment, the polymer P can be used in a process for bonding a paint or a varnish or an ink to a metallic surface (S1), including: treating all or parts of said metallic surface (S1) with a composition comprising the copolymer ; and applying a paint or varnish or ink to the treated surface (S1).

In a third embodiment, the polymer P can be used as an additive in coating compositions, including but not limited to inks and paints, such as solvent-borne and powder paints. This means that the copolymer can be incorporated into inks and paints, including for example solvent-borne paints and powder paints as additives that promote the adhesion of the ink/paint to a substrate and/or the adhesion of another coating on the ink/paint. In particular, the copolymer can be used in Pre-Coated-Metal (PCM) applications, i.e. in pre-coated (painted) metal coils such as coils which are used in architectural applications. The idea is to introduce the copolymer into the paint to improve the adhesion of the paint to the substrate, in particular to improve "formability" when the painted coil is cut into a sheet then transformed into corrugated sheet metal, etc. while the paint still has to continue to adhere perfectly to the metal sheet. Another advantage of this embodiment is an improved paint adhesion during storage, e.g. in humid conditions, as well as an improved corrosion resistance.

Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

BRIEF DESCRIPTION OF THE FIGURES

Figures 1 , 2, and 3 are the graphs of the friction coefficient evolution in function of the temperature of lubricating compositions made in the experimental section below.

EXPERMENTAL PART

Raw material used

Table 1. Commercial references of raw material used

Preparation of Polymer P according to the invention: Synthesis of a copolymer poly(vinylphosphonic acid-co-2-ethylhexyl acrylate-co-dodecyl acrylate-co-dodecyl methacrylate) (Poly(VPA-co-2-EHA-co-LA-co-LMA) (7.5/46.5/23/23 mol%) by conventional radical polymerization in ethyl acetate (EtOAc) (initiator: 2,2'-Azobis-2- methylbutyronitrile, AM BN)

In a 2.5L jacketed reactor equipped with a multi-stage lightning A320 stirring blade, counterblades, a condenser connected to a minichiller and a cryothermostatic bath were added 31.02 g (0.230 mol) of VPA (80% purity), 40.17 g (0.214 mol) of 2-EHA (98% purity), 28.22 g (0.106 mol) of LA (90% purity), 28.00 g (0.106 mol) of LMA (96% purity) and 394.38 g of ethyl acetate. The reaction mixture was degassed by bubbling nitrogen under agitation while the temperature of the cryothermostatic bath was programmed at 70°C over a temperature ramp of 1 hour. Once the temperature of 70°C was reached, the nitrogen flow was left in the sky and a 65 wt% (meth)acrylate solution of the three comonomers 2-EHA (227.61 g, 1.210 mol), LA (159.91 g, 0.599 mol) and LMA (158.66 g, 0.599 mol) in ethyl acetate (252.73 g) was introduced over 9 hours by means of a syringe pump under stirring. The reaction was started by adding 34.19 g of an 8 wt% AMBN solution (2.78 g, 0.0142 mol, 98% purity) in ethyl acetate (31.42 g) in one shot. After 3 hours reaction, 45.11 g of an 12.3 wt% AMBN solution (5.64 g, 0.029 mol, 98% purity) in ethyl acetate (39.47 g) was introduced over 6 hours by means of a syringe pump. Once the feed of initiators and monomers was completed, the reaction mixture was aged at 70°C for a further 11 hours whereupon it was cooled to ambient temperature and discharged. A sample was taken and analyzed by ¹H NMR in CDCI3. The final conversion in 2-EHA, LA and LMA was above 99%. The final conversion in VPA was around 74%. The molecular weight was determined by size exclusion chromatography (SEC) coupled with a Rl and a multi-angle light scattering diffusion (MALLS) detector. /W_n, SEC-MALLS = 45,000 g mol’¹; /W_w, SEC-MALLS = 101 ,000 g mol’¹; D = 2.3. The product was then transferred to EHC45 base oil and the ethyl acetate was removed under reduced pressure (40 mbar) at 50°C using a rotavap. The final solid content was 33.3 wt%.

Method for measuring the molecular weight:

Size exclusion chromatography (SEC) samples were diluted in a mobile phase (THF + 0.01 M tetrabutylammonium tetrafluoroborate + 100 pL trifluoroacetic acid per kg of eluent) and filtered (on 0.45 pm Millipore) before analyzing.

The samples were analyzed by SEC eguipped with a Multi-Angle Laser Light Scattering (MALLS) detector accordingly to the conditions below:

• Eluent: THF + 0.01 M tetrabutylammonium tetrafluoroborate + 100 pL trifluoroacetic acid per kg of eluent

• Flow rate: 1 mL»min’¹

• Columns: Agilent Polypore (2*30 cm) + guard column

• Detection: Rl (Agilent detector) + MALLS Mini Dawn TREOS

• Samples concentration: 3 mg»mL’¹ in the mobile phase

• Injection volume: 100 pL

Synthesis of a copolymer poly(2-(phosphonooxy)ethyl methacrylate-co-2- ethylhexylacrylate-co-dodecylacrylate-co-dodecylmethacrylate) (Poly(Sipomer® PAM4000-co-2-EHA-co-LA-co-LMA) (8/46/23/23 mol%) in the present invention by conventional radical polymerization in ethyl acetate (EtOAc) (initiator: 2,2'-Azobis-2- methylbutyronitrile, AMBN)

In a 2.5L jacketed reactor eguipped with a multi-stage lightning A320 stirring blade, counterblades, a condenser connected to a minichiller and a cryothermostatic bath were added 3.39 g (0.012 mol) of a 74.9 wt% Sipomer® PAM4000 solution in EtOH, 12.81 g (0.069 mol) of 2-EHA (99% purity), 11.26 g (0.042 mol) of LA (90% purity), 11.17 g (0.044 mol) of LMA (96% purity), 7.71 g (0.040 mol) of AMBN (98% purity) and 395.38 g of ethylacetate. The reaction mixture was degassed by bubbling nitrogen under agitation while the temperature of the cryothermostatic bath was programmed at 70°C over a temperature ramp of 1 hour. Once the temperature of 70°C had been reached, the nitrogen flow was left in the sky and two separate monomer solutions were introduced in parallel over 6 hours by means of a syringe pump under stirring. The first one was a mixture of the three monomers 2-EHA, LA and LMA: 690.56 g of solution containing 2-EHA (237.70 g, 1.289 mol), LA (158.28 g, 0.658 mol), LMA (167.52 g, 0.658 mol) and EtOAc (127.06 g). The second one was a 74.9 wt% Sipomer® PAM4000 solution in EtOH (64.47 g, 0.230 mol). Once the feed of monomers was completed, the reaction mixture was aged at 70°C for a further 4 hours whereupon it was cooled to ambient temperature and discharged. A sample was taken and analyzed by ¹H NMR in CDCI3. The final conversion in 2-EHA and LA was 94% while the conversion in LMA and Sipomer® PAM4000 was >99%. The product was then transferred to EHC45 base oil and the ethyl acetate was removed under reduced pressure (40 mbar) at 50°C using a rotavap. The final solid content was 50 wt%.

Preparation of other comparative polymers

Two comparative polymers have been prepared according to example 1 and 2 of WO 2016/177839A1 , based on VPA and 2EHA. Those polymers are different from the polymer according to the invention notably because they do not contain at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate.

Those polymers have not been tested in the friction test below because they were presenting solubility issues in the Group II base oil.

Another comparative polymer has been prepared in view of demonstrating the impact of the presence of VPA in the polymer backbone, notably for anti-wear properties. This comparative polymer P’ is prepared according to the following process:

Preparation of Polymer P’: Synthesis of a copolymer poly(2-ethylhexyl acrylate-co- dodecyl acrylate-co-dodecyl methacrylate) (Poly(2-EHA-co-LA-co-LMA) (49/25/26 mol%) by conventional radical polymerization in ethyl acetate (EtOAc) (initiator: 2,2'- Azobis-2-methylbutyronitrile, AMBN)

In a 0.75L jacketed reactor equipped with a Mixel TT stirring blade, counter-blades, a condenser connected to a minichiller and a cryothermostatic bath were added 4.80 g (0.026 mol) of 2-EHA (98% purity), 3.13 g (0.013 mol) of LA (90% purity), 2.61 g (0.014 mol) of AMBN (98% purity) and 106.57 g of ethyl acetate. The reaction mixture is degassed by bubbling nitrogen through under agitation while the temperature of the cryothermostatic bath is programmed at 70°C over a temperature ramp of 1 hour. Once the temperature of 70°C has been reached, the nitrogen flow is left in the sky and two different solutions of (meth)acrylate are added dropwise; a 60wt% (meth)acrylate solution of the two comonomers 2-EHA (91.25 g, 0.495 mol) and LA (59.51 g, 0.248 mol) in ethyl acetate (100.5 g) is introduced over 4 hours and pure LMA (96% purity) solution (69.06 g, 0.261 mol) is introduced over 6 hours by means of a syringe pump under stirring. Once the feed of monomers is completed, the reaction mixture was aged at 70°C for a further 10 hours whereupon it was cooled to ambient temperature and discharged. A sample was taken and analyzed by ¹H NMR in CDCI3. The final conversion in 2-EHA, LA and LMA is above 99%. The molecular weight was determined by size exclusion chromatography (SEC) coupled with a Rl and a multi-angle light scattering diffusion (MALLS) detector. M_n, SEC-MALLS = 41 ,000 g mol’¹; M_w, SEC-MALLS = 109,000 g mol’¹; B = 2.7. The product is then transferred to EHC45 base oil and the ethyl acetate is removed under reduced pressure (40 mbar) at 50°C using a rotavap. The final solid content was 33.3 %.

Lubricating Compositions

Preparation: In a 100 mL beaker, a 50 g formulation is prepared containing the base oils and the other compounds in the proportions described below in Table 2. They are mixed using mechanical stirring at 750 rpm for 15 min, at 60°C. The resulting compositions are bright and clear except with the use of MoDTC turning the blend slightly green.

Formulations are done in a Group II base oil mixture having a kinematic viscosity at 9 cSt at 100°C to mimic a typical engine oil (SAE 20 grade).

Table 2. Compositions in % by weight Friction Test:

Material: Apparatus HFRR (High Frequency Reciprocating Rig): A ball-on-plate reciprocating friction system from PCS Instruments.

Method: For each of the above prepared compositions, the friction coefficient has been measured by HFRR: slide ball on disc: metal/metal under a 200 g load at a 1000 microns stroke, at 40°C for 15 min and then ramped to 150°C at 2°C/min for 55 min. The method used is the one described in ASTM D6079, except for the diesel fuel which has been replaced by the formulations that are presented in Table 3 and the constant time and temperature of 60°C for 75 min has been replaced by a warm-up phase (40°C for 15 min) and a ramp-up phase (150°C at 2°C/min for 55 min.)

Results :

Table 3. Friction reduction results The above results have been converted into graphs in order to highlight the differences between the invention and the comparative examples.

In Fig 1., it is shown that the polymer according to the invention (Inv 1) is as good as the benchmark ZDDP (Comp 2) as anti-wear agent for lubricating compositions, as the friction coefficient is reduced to an absolute value below or equal to 0.17 all along the ramping (40- 150°C) and decreased of 37% at 150°C compared to an oil based lubricant composition comprising no additive (Comp 1). In Fig 2., which is presented to show the results of Inv 2, we can notice that by adding the polymer P and GMO as friction modifier (Inv 2) in an oil based composition we obtain a synergistic effect which is not expected. Indeed, the same effect of boosting the reduction of the friction coefficient is not obtained with ZDDP and GMO (Comp 5). The skilled person would have expected intermediate results at 150°C between Comp 3 and Inv 1 , as it is the case for Comp 5 which is an intermediate result between Comp 2 and Comp 3. Surprisingly, the friction coefficient is reduced well below Comp 3 for Inv 2. This effect is also highlighted in Table 3, wherein it is shown that the % of friction reduction at 150°C compared to an oil based composition comprising GMO but without anti-wear AW is of +22% for Inv 2 (P+GMO) whereas it is of -21 % for Comp 5 (ZDDP+GMO). It can also be seen that the % of friction reduction at 150°C compared to an oil based composition comprising the same anti-wear AW but no GMO is of +45% for Inv 2 (P+GMO) whereas it is of +16% for Comp 5 (ZDDP+GMO).

In Fig 3. which is presented to show the results of Inv 3, we can notice that by adding the polymer P and MoDTC as friction modifier (Inv 3) in an oil based composition we also obtain a synergistic effect which is not expected. Indeed, the same effect of boosting the reduction of the friction coefficient is not obtained with ZDDP and MoDTC (Comp 6). The skilled person would have expected a result at 150°C close to Comp 4 (MoDTC alone), as it is the case for Comp 6. Surprisingly, the friction coefficient is reduced well below Comp 4 for Inv 3. This effect is also highlighted in Table 3, wherein it is shown that the % of friction reduction at 150°C compared to an oil based composition comprising MoDTC but without anti-wear AW is of +37% for Inv 3 (P+MoDTC) whereas it is of -7% for Comp 6 (ZDDP+MoDTC). It can also be seen that the % of friction reduction at 150°C compared to an oil based composition comprising the same anti-wear AW but no MoDTC is of +65% for Inv 3(P+MoDTC) whereas it is of +42% for Comp 6 (ZDDP+MoDTC).

Anti-wear Test:

Material and Methods:

4 ball wear test: A 4 ball rig is used like the Falex four-ball tester. The test is made according to ASTM D4172. All the tests run for 60 min at 75°C under a 40 kg load, at a 1200 rpm speed.

Each candidate is added at 1wt% in a Group II mixture base oil of 45 wt% of a base oil at 6.5 cSt at 100°C and 55% of a base oil at 12 cSt at 100°C to meet an overall kinematic viscosity at 9 cSt at 100°C. Pin and Vee wear test: The Falex Pin and Vee block is used to run this test.

Test is run for 3 min at 100 lb and then for 2 hr at 300 lb.

Each candidate is added at 1wt% in a Group II mixture base oil of 45 wt% of a base oil at

6.5 cSt at 100°C and 55% of a base oil at 12 cSt at 100°C to meet an overall kinematic viscosity at 9 cSt at 100°C.

Results :

Table 4 The results are showing that the Invention 1 brings a good anti-wear performance both on the 4 ball wear test and on the Pin and Vee wear test. Wear scar produced on the 4 ball wear test is smaller than the Comparatives 1 and 3 and equivalent to ZDDP, a standard anti-wear. Similar performance is observed on the Pin and Vee wear test on weight loss and diameter loss of the pin.

Claims

1. Use of a composition comprising at least one polymer P obtained by radical copolymerization of a mixture comprising :

- at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and

- at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; as friction coefficient reducer agent in oil-based lubricating compositions for engines and transmissions without clutch.

2. The use according to claim 1 , as both anti-wear agent and friction coefficient reducer agent in oil-based lubricating compositions for engines and transmissions without clutch.

3. The use according to claim 1 or 2, wherein the monomer M1 is selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n- propyl (meth)acrylate, iso-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, iso-hexyl (meth)acrylate, n- heptyl (meth)acrylate, iso-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2- ethylhexyl (meth)acrylate, iso-octyl (meth)acrylate, n-nonyl (meth)acrylate, preferably 2-ethylhexyl (meth)acrylate.

4. The use according to any one of claims 1 to 3, wherein the monomer M2 is selected from the group consisting of n-undecyl (meth)acrylate, iso-undecyl (meth)acrylate, iso-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, n-octadecyl (meth)acrylate, n-nonadecyl (meth)acrylate, dodecyl (meth)acrylate, n-eicosyl (meth)acrylate, and n-tricosyl (meth)acrylate, preferably Dodecyl acrylate and Dodecyl methacrylate.

5. The use according to any one of claims 1 to 4, wherein the polymer P comprises at least one monomer M2’ being a C11-C30 alkyl acrylate and at least one monomer M2” being a C11-C30 alkyl methacrylate, more preferably dodecyl acrylate and dodecyl methacrylate.

6. The use according to claim 5, wherein the polymer P is obtained by radical copolymerization of a mixture consisting essentially of:

- vinylphosphonic acid;

- 2-ethylhexyl acrylate;

- dodecyl acrylate and

- dodecyl methacrylate.

7. The use according to claim 6, wherein the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of vinylphosphonic acid, 2-ethylhexyl acrylate, dodecyl acrylate and dodecyl methacrylate:

8. A synergistic composition comprising:

- at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and

- at least one monomer M2 being a C11-C30 alkyl acrylate or methacrylate; and

• at least one friction modifier agent FM selected from the group consisting of organomolybdenum friction modifiers such as molybdenum dialkyl dithiocarbamates and molybdenum dialkyl dithiophosphate, and organic friction modifiers such as glycerol esters, fatty amides and fatty amines, preferably Molybdenum dithiocarbamate and glycerol monooleate.

9. The synergistic composition according to claim 8, wherein the polymer P comprises at least one monomer M2’ being a C11-C30 alkyl acrylate and at least one monomer M2” being a C11-C30 alkyl methacrylate, more preferably dodecyl acrylate and dodecyl methacrylate.

10. The synergistic composition according to claim 8 or 9, wherein the polymer P is obtained by radical copolymerization of a mixture consisting essentially of:

- vinylphosphonic acid;

- 2-ethylhexyl acrylate;

- dodecyl acrylate and

- dodecyl methacrylate.

11 . The synergistic composition according to claim 10, wherein the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of vinylphosphonic acid, 2-ethylhexyl acrylate, dodecyl acrylate and dodecyl methacrylate:

12. The synergistic composition according to any one of claims 8 to 11 , wherein the composition comprises from 0.1 to 10% by weight, preferably from 0.5 to 2.5% by weight, based on the total weight of the composition, of at least one friction modifier agent FM, preferably glyceryl monooleate.

13. A synergistic oil based lubricant composition for engine and transmission without clutch comprising: at least a base oil, preferably a mineral oil of group II or III or a synthetic base oil, notably a group IV synthetic base oil, or a mixture thereof, and a synergistic composition as defined in any one of claims 8 to 12.

14. A polymer obtained by radical copolymerization of a mixture comprising:

- at least one monomer M1 being a C1-C10 alkyl acrylate or methacrylate; and

- at least one monomer M2’ being a C11-C30 alkyl acrylate and at least one monomer M2” being a C11-C30 alkyl methacrylate.

15. The polymer according to claim 14 which is obtained by radical copolymerization of a mixture consisting essentially of:

- vinylphosphonic acid;

- 2-ethylhexyl acrylate;

- dodecyl acrylate and

- dodecyl methacrylate.

16. Use of a composition comprising at least one polymer according to claim 14 or 15: as polymeric anti-wear and friction modifier in lubricants ( including but not limited to engines, transmissions, hydraulic systems); and/or in metalworking fluids ( including but not limited to forming fluids and removing fluids) and/or in greases including but not limited to bearings, gears, wire ropes); or as an adhesion promoter and/or additive providing corrosion resistance, namely in the adhesive bonding of two surfaces, for bonding a paint or varnish or ink to a metallic surface, or as an additive in coating compositions.