EP4649126A1

EP4649126A1 - Lubricant composition

Info

Publication number: EP4649126A1
Application number: EP24700021.9A
Authority: EP
Inventors: Christine HAMON; Andrea LOTIERZO
Original assignee: Syensqo Specialty Polymers Italy SpA
Current assignee: Syensqo Specialty Polymers Italy SpA
Priority date: 2023-01-12
Filing date: 2024-01-10
Publication date: 2025-11-19
Also published as: WO2024149804A1; JP2026500853A; CN120530184A

Abstract

The present invention relates to a lubricant composition comprising a (per)fluoropolyether polymer as base oil, a salt of a (per)fluoropolyether polymer as a conductive additive and at least one thickener.

Description

Lubricant composition

Cross reference to related patent applications

[0001] This application claims priority filed on 12 January 2023 in Europe with Nr. 23151394.6, the whole content of this application being incorporated herein by reference for all purposes.

Technical field

[0002] The present invention relates to a lubricant composition comprising a (per)fluoropolyether polymer as base oil, a salt of a (per)fluoropolyether polymer as a conductive additive and at least one thickener.

Background

[0003] It is known that certain hydrogen-based lubricants of natural or synthetic origin, in particular certain lubricant oils, are endowed with remarkable lubricant properties and are available on the market at reasonable costs. Examples of hydrogen-based lubricant oils comprise mineral oils of hydrocarbon type, animal and vegetal hydrogenated oils, synthetic hydrogenated oils including polyalphaolefins (PAOs), dibasic acid esters, polyol esters, phosphate esters, polyesters, alkylated naphthalenes, polyphenyl ethers, polybutenes, multiply-alkylated cyclopentanes, silane hydrocarbons, siloxanes and polyalkylene glycols.

[0004] To operate at high temperature, the thickening additive should have excellent thermal and chemical stability. In addition, fluorinated oils and greases suffer degradative processes at high temperatures in the presence of metals and in an oxidizing environment, which break the backbone chains producing volatile products. This leads to the loss of the lubricating performances of both oils and greases. [0005] To overcome this drawback, it is known from the prior art to use additives that stabilize the oils and greases at high temperatures in an oxidizing environment and in the presence of metals, thus guaranteeing their stability during the use.

[0006] Liquid stabilizing additives were disclosed in the prior art. However, for applications wherein a continued use at high temperatures, higher than 200°C, is required, it is necessary to increase the additive amount, generally to values higher than about 5% by weight over the total weight of the oil or grease. The drawback of using liquid stabilizing additives in high amounts in the preparation of greases resides in that the ratios between the liquid component of the grease (the oil plus additive) and the solid component of the grease (the thickener) are changed. High amounts of the liquid causes an increase of the liquid separation from the solid as the temperature increases, thus changing the initial grease consistency. The oil separation becomes significant at temperatures higher than 200°C. Furthermore, as the working temperatures increase, the liquid additives tend to evaporate more easily.

[0007] The use of polymers that are solid at room temperature and have a melting point higher than 150°C, was disclosed for example in WO 2007/082829 (Solvay Solexis S.p.A.). This patent application discloses the use of polymers containing at least one aromatic ring in their backbone as additives to stabilize perfluoropolyether oils. The compositions disclosed in this patent application comprised aromatic polymer powder having an average size preferably between 0.1 pm and 1 ,000 pm. Preferred embodiment comprised, in addition to said aromatic polymer powder, PTFE powder.

[0008] A possible alternative to hydrogen-based lubricants is represented by (per)fluoropolyether (PFPE) lubricants, i.e. lubricants comprising a perfluorooxyalkylene chain, that is to say a chain comprising recurring units having at least one ether bond and at least one fluorocarbon moiety. PFPE lubricants are endowed with high thermal and chemical resistance, so they are useful in cases of applications characterized by harsh conditions (very high temperatures, presence of oxygen, use of aggressive chemicals and radiations, etc.). However, PFPE oils are more expensive than hydrogenated oils and hence they are used only when high performances are requested.

[0009] (Per)fluoropolyether polymers (PFPEs) are a family of fluorinated synthetic fluids, which have been known for a long time and are used to formulate lubricants that function for long periods of time in extreme environments.

[0010] However, one problem with PFPE-based lubricants is that they are highly dielectric and have poor electrical conductivity. Furthermore, low polarity of the fluorinated PFPE lubricants leads to poor solubility and/or affinity with most additives. Therefore, tailoring the conductivity of PFPE lubricants has proven to be problematic because conductive additives, which are typically polar species, are immiscible with PFPE lubricants.

[0011] Accordingly, several methods have been tried in the art to tailor the conductivity of PFPE lubricants, for example as disclosed in US 2008/0144219 (in the name of HGST Netherlands BV).

[0012] Also, N Suhaila A Japar et al. (International Journal of Engineering & Technology, 7, 3.26, 2018, 23.29) in “Grease and its Application on Electrical Equipment: a Review” summarizes the findings in relation with the use of greases containing a PFPE as the base oil and solid particles (fumed silica or polytetrafluoroethylene - PTFE) as the thickener.

Summary of the invention

[0013] The Applicant is aware that the presence of electrical components is continuously growing in many different industries and for a variety of applications. However, their exposure to harsh environments, including without limitation very high temperatures, moisture, and corrosion, can accelerate the failure of such electrical components. Also, such components can undergo electric arc discharge burnings, which cause burnings on the components and hence decrease their lifetime. [0014] Further to the above, the Applicant noted that the performances of the aromatic polymer powders used in the art are no longer suitable to meet the ever increasing requirements of specialty industries.

[0015] Hence, the Applicant faced the problem of providing a composition suitable to lubricate electrical components suitable for use in different applications and industries, such as in particular electric, electronic and automotive industries. Indeed, the Applicant is aware that nowadays the electrical erosion in rolling bearings is a challenge for e-mobility for many reasons - among which: the inverter control systems can lead to complex shaft voltages; EDM bearing currents occur when the bearing voltage exceeds the threshold voltage of the insulating lubricating film; the energy of the capacitor is released by destructive currents and arcing; the discharge currents can damage the bearing surface and degrade the lubricating grease (radical formation, overheating).

[0016] Such composition needs to show good electric conductivity and hence reduced volume resistivity (also referred to as “electrical resistivity” or “electrical resistance”), good viscosity and high viscosity index ("as measured according to ASTM D227), as well as outstanding compatibility between the base oil and the additive(s).

[0017] The Applicant has surprisingly found a composition that meets the above mentioned requirements and can be hence used as such as lubricant for electrical and electronic components, including electrical connectors, switchgears and circuit breakers, as well as for mechanical components, in particular suitable for use in the automotive industry, including to lubricate parts used in electric vehicles, such as ball bearings.

Disclosure of the invention

[0018] In the present application:

- the use of parentheses around symbols or numbers identifying the formulae, for example in expressions like “polymer (P)”, etc., has the mere purpose of better distinguishing the symbol or number from the rest of the text and, hence, said parenthesis can also be omitted;

- the acronym “PFPE” stands for "(per)fluoropolyether” and, when used as substantive, is intended to mean either the singular or the plural form, depending on the contex-t;

- the prefix "(per)" in the term "(per)fluoropolyether” means that the polyether can be fully or partially fluorinated.

[0019] In a first aspect, the present invention relates to a composition [composition (COMP)] comprising:

(A) a (per)fluoropolyether polymer-base oil [PFPE base oil];

(B) up to 20.0 wt.% based on the total weight of composition (COMP) of at least one salt of a (per)fluoropolyether polymer [PFPE additive] comprising a (per)fluoropolyether backbone having two chain ends bonded to opposite sides of said backbone, wherein at least one chain end comprises at least one group selected from:

(i) acid group selected from:

-coo-, wherein each is salified with at least one inorganic metal salt or with an organic group selected from ammonium salt and phosphonium salt;

(ii) ammonium group and at least one inorganic or organic counterion; and

(C) from 0.1 % to 35.0% by weight, preferably from 1 .0% to 32.0% by weight, based on 100% by weight of said composition, of at least one thickener selected from fluorinated polymer and/or aromatic polymer.

[0020] Surprisingly, the Applicant found that composition (COMP) has excellent thermal and thermo-oxidative stability, while the PFPE additive allows to dissipate the static charges.

[0021] Preferably, the PFPE base oil is selected from the group comprising:

(A-l) (per)fluoropolyether polymer [PFPE polymer] comprising a linear or branched (per)fluoropolyether chain [PFPE chain] having two chain ends bonded to opposite sites of said chain, both chain ends comprising a linear or branched perfluorinated alkyl chain having from 1 to 6 carbon atoms, said polymer having a number average molecular weight from 500 to 100000, preferably from 2000 to 50000 as measured by NMR; or

(A-l I) at least one block copolymer [PFPE copolymer] comprising a first and a second (per)fluoropolyether chain [PFPE chain] each having two chain ends, wherein the first chain end of said first and second PFPE chain comprises a perfluorinated alkyl group and the second chain end of said first and second PFPE chain are bonded to each other via:

- at least one first block [block (1 )] complying with formula (I): wherein n is 0 or an integer from 1 to 3;

Ri to R4, each independently, is selected in the group comprising, preferably consisting of, fluorine atom, perfluorinated linear or branched alkyl group having from 1 to 6 carbon atoms, group of formula (II):

(II) -(Rio)t[C(Rn)(Ri2)-C(Ri3)(Ri4)(Ri5)]z wherein

Rio is an oxygen atom, or a bi-/tri-/tetravalent perfluorinated alkyl chain comprising from 1 to 24 carbon atoms optionally interrupted by and/or comprising at least one oxygen atom, t is zero or 1 , z is an integer from 1 to 3;

Ri 1 to R15, each independently, is selected in the group comprising, preferably consisting of, fluorine atom, perfluorinated linear or branched alkyl group having from 1 to 6 carbon atoms and group of formula (III): 4(A*)3A-(BV-(E^A)LA]UA-(C*)-T (III) wherein a^ is zero or 1, v^ is zero or an integer from 1 to 3, L^ is zero or an integer from 1 to 250, u^ is zero or an integer from 1 to 50; A^ is a PFPE chain B^ is a group of formula: -[C(R1^)(R2^)-C(R3^)(R4^)]- wherein R_1^ to R_4^ each independently has the meaning defined above for each of R1 to R4, E^ is a group of formula -(CR100^R101^CR102^R103^)- wherein R_100^ and R_101^ are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom, and R102^ and R103^ are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom; linear or branched alkyl chain comprising from 1 to 6 carbon atoms, optionally containing at least one heteroatom selected from O, N and S; -OR200 wherein R200 is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms; or one of R_100^ and R_101^ and one of R_102^ and R_103^ are a fluorine atom and the other of R100^ and R101^ and the other of R102^ and R103^ together form a perhalogenated cyclic ring having from 4 to 6 members, optionally comprising heteroatoms, such as oxygen atoms; C^ is a PFPE chain, and T is a perfluorinated alkyl group; - at least one second block [block (2)] complying with formula (IV): -[(CR^1*R^2*CR^3*R^4*)n*-(E)L]- (IV) wherein n* is zero or an integer from 1 to 250, L is zero or an integer from 1 to 250 and the sum of n* and L is 0 or from 1 to 250; R^1* and R^2* are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom, and R^3* and R^4* are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom; linear or branched alkyl chain comprising from 1 to 6 carbon atoms, optionally containing at least one heteroatom selected from O, N and S; -OR₂₀₀ wherein R₂₀₀ is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms; or one of R^1* and R^2* and one of R^3* and R^4* are a fluorine atom and the other of R^1* and R^2* and the other of R^3* and R^4* together form a perhalogenated cyclic ring having from 4 to 6 members, optionally comprising heteroatoms, such as oxygen atoms; E has the same meaning provided for E^ above; - optionally, at least a third block [block (3)] comprising a PFPE chain; with the proviso that: in said PFPE copolymer: -- at least one of n, n* and L is different from 0; -- said block (1), said block (2) and when present said block (3) are statistically distributed; in said formula (I): -- at least one of R₁ to R₄ is a group of formula (II), -- one of R11 or R12 and one of R13 to R15, is a group of formula (III); in said formula (III) and said formula (IV) -- the recurring units are statistically distributed, in said formula (III) -- when a^ is 1 at least one of v^ and L^ is different from 0. [0022] Preferably, each of the PFPE chain mentioned above both in the PFPE polymer and in the PFPE copolymer is a partially or fully fluorinated chain [chain (Rf)] comprising, preferably consisting of, repeating units R°, said repeating units being independently selected from the group consisting of:

(i) -CFXO-, wherein X is F or CF3;

(ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF3, with the proviso that at least one of X is -F;

(iii) -CF2CF2CW2O-, wherein each of W, equal or different from each other, are F, Cl, H;

(iv) -CF2CF2CF2CF2O-;

(v) -(CF2)W-CFZ-O- wherein w is an integer from 0 to 3 and Z is a group of general formula -O-R(f-a)-Y, wherein R(f-a) is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings : -CFXO- , -CF2CFXO-, -CF2CF2CF2O-, - CF2CF2CF2CF2O-, with each of each of X being independently F or CF3 and Y being a C1-C3 perfluoroalkyl group.

[0023] Preferably, chain (Rf) complies with the following formulae (Rf-I) and (Rf-ll): (Rf-I)

-[(CFX¹O)gl(CFX²CFX³O)g2(CF2CF2CF2O)g3(CF2CF2CF2CF2O)g4]- wherein

- X¹ is independently selected from -F and -CF3,

- X², X³, equal or different from each other and at each occurrence, are independently -F, -CF3, with the proviso that at least one of X is -F;

- g1 , g2, g3, and g4, equal or different from each other, are independently >0, such that g1 +g2+g3+g4 is in the range from 2 to 300, preferably from 10 to 250, even more preferably from 15 to 200; should at least two of g1 , g2, g3 and g4 be different from zero, the different recurring units are generally statistically distributed along the chain;

(Rf-ll)

-[(CFX¹0)g1 (CFX²CFX³O)g2(CF2CF2CF2O)g3(CF2CF2CF2CF₂O)g4- (CF(CF3)O)g5(CF2CF(CF₃)O)g6]- wherein

- X¹, X², X³ are as defined above;

- g1 , g2, g3, g4, g5 and g6, equal or different from each other, are independently >0, such that g1 +g2+g3+g4+g5+g6 is in the range from 2 to 300, preferably from 10 to 250, with the proviso that at least one of g5 and g6 are different from 0.

[0024] In a preferred embodiment, chain (Rf) complies with formula (Rf-I) above.

[0025] Preferably, the (A— 11) PFPE copolymer used in composition (COMP) of the present invention is as described herein after.

[0026] Preferably, said PFPE copolymer has a viscosity of at least 1 ,000 mm²/s, measured at 20°C according to standard methods, such as ASTM D445, or with a dynamical mechanical spectrometer Anton Paar MCR 502 rheometer equipped with parallel plates 25 mm, at 0.1 rad/s and at 25°C.

[0027] It will be understood by those skilled in the art that said first chain end of said first and second PFPE chain correspond to the two chain ends of the PFPE copolymer.

[0028] Preferably, said first chain end of said first and second PFPE chain comprise a perfluorinated linear alkyl group having from 1 to 3 carbon atoms.

[0029] Preferably, said perfluorinated alkyl groups are the same from each other.

[0030] Preferably, said first chain end of said first and second PFPE chain and said T in formula (III), equal or different from each other, are a perfluorinated alkyl group having from 1 to 3 carbon atoms.

[0031 ] For example, T and T’, equal to or different from each other, are a fluorine atom or a group selected from -CFs, -CF2CF3, -CF2CF2CF3, -CF(CF3)2. Other halogenated groups, such as for example -CF2CI and -CF2CF2CI, can still be present.

[0032] Preferably, in said first and second PFPE chain, A^A and C^A are equal or different from each other.

[0033] Preferably, in the PFPE copolymer, said first PFPE chain is bonded to said block (1 ) via a sigma bond or a group -(C)- selected from -CF2-, -CF2CF2- or - O-. [0034] Preferably, in the PFPE copolymer, said block (2) is bonded to said second PFPE chain via a sigma bond or a group -(C)- selected from -CF2-, -CF2CF2- or -O-.

[0035] Preferably, when both said block (1 ) and said block (2) are present, they are linked via a sigma bond.

[0036] Preferably, in the PFPE copolymer, the sum of (n + n* + v^A) is from 1 to 15, preferably from 1 to 11 , more preferably from 1 to 9.

[0037] Preferably, in the PFPE copolymer, the sum of (L+L^A) is from 1 to 500, preferably from 2 to 500, more preferably from 2 to 300,

[0038] According to a preferred embodiment, the PFPE copolymer comprises a first and a second PFPE chain, each having two chain ends, wherein the first chain end of said first and second PFPE chain comprises a perfluorinated alkyl group and the second chain end of said first and second PFPE chain are bonded to each other via:

- at least one block (2) complying with formula (IV): -[(CR¹*R²XR³*R⁴*)n*-(E)i_]- (IV) wherein n* is an integer from 1 to 250,

L is an integer from 1 to 250, and the sum of n* and L is from 1 to 250;

R¹* and R²* are fluorine atom, and

R³* and R⁴* are independently selected from halogen atom, more preferably fluorine or chlorine atom; linear or branched alkyl chain comprising from 1 to 6 carbon atoms, optionally containing at least one heteroatom selected from O, N and S; -OR200 wherein R200 is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms;

E is a group of formula -(CRIOO^ARIOI^ACRIO2^AR-IO3^A)- wherein

RWO^A and RWI^A are independently selected from halogen atom, preferably fluorine or chlorine atom, and

RW2^A and RW3^A are independently selected from halogen atom, preferably fluorine or chlorine atom; -OR200 wherein R200 is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms; and

- optionally, at least one block (3) comprising a PFPE chain.

[0039] The viscosity of the PFPE copolymer can be measured using different methods depending on the viscosity of the PFPE copolymer itself.

[0040] Preferably, said PFPE copolymer has a viscosity higher than 1 ,000 mm²/s at 20°C, more preferably higher than 2,000 mm²/s at 20°C and even more preferably higher than 3,000 mm²/s at 20°C.

[0041 ] Preferably, said PFPE copolymer has a viscosity lower than 5,000,000 mm²/s at 20°C, more preferably lower than 2,500,000 mm²/s at 20°C, and even more preferably lower than 2,000,000 mm²/s at 20°C.

[0042] Preferably, said PFPE copolymer has a viscosity of from 3,000 to 1 ,500,000 mm²/s at 20°C, more preferably of from 3,500 to 1 ,000,000 mm²/s at 20°C and even more preferably of from 4,000 to 950,000 mm²/s at 20°C .

[0043] The above viscosity of the PFPE copolymer according to the present invention was measured at 25°C according to standard methods, such as ASTM D445, or with a dynamical mechanical spectrometer Anton Paar MCR 502 rheometer equipped with parallel plates 25 mm, at 1 rad/s and at 25°C.

[0044] The PFPE copolymer can be prepared via known processes, for example as disclosed in WO 2008/065163 (SOLVAY SOLEXIS S.P.A.) or via supercritical fluid fractionation.

[0045] More preferably, the PFPE copolymer can be prepared via a process [process (P)], which comprises

(a) contacting:

- at least one (per)fluoropolyether polymer comprising peroxidic groups [PFPE peroxy]; with

- at least one perfluorinated compound of formula (X-p):

(X-p) wherein each of R21 to R23 and R31 to R33 is independently fluorine atom, perfluorinated alkyl group having from 1 to 3 carbon atoms,

R10 is an oxygen atom, or a perfluorinated alkyl chain comprising from 2 to 18 carbon atoms, optionally and preferably interrupted by and/or comprising at least one oxygen atom, t is zero or 1 , preferably 1 ; each of z* and z** is independently 1 or 2; and/or

- at least one compound [compound (0)] selected in the group comprising, preferably consisting of:

(i) hydrogenated or (per)halogenated olefin comprising from 2 to 8 carbon atoms, preferably ethylene (E), propylene (PP), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), chlorotrifluoroethylene (CTFE), and 1 ,1 - difluoroethylene (VDF);

(ii) CF₂=CFORf, wherein

Rf is a C1-C6 (per)fluoroalkyl group, preferably -CF3, -C2F5, -C3F? (also referred to as “PAVE” hereinafter); a group C1-C12 [(per)fluoro]-oxyalkyl comprising catenary oxygen atoms, preferably perfluoro-2-propoxypropyl group (also referred to as “perfluoro-oxy-alkyl-vinyl ethers” hereinafter); a group -CF2ORf2 (also referred to as “perfluoro-methoxy-vinyl ethers” or “MOVE” hereinafter) wherein Rf2 is selected from the group consisting of C-i- C6 perfluoro-alkyls; C5-C6 cyclic perfluoro-alkyls, and C2-C6 perfluoro-oxy- alkyls, comprising at least one catenary oxygen atom, preferably R_f2 is - CF₂CF₃ (MOVE1), -CF₂CF₂OCF₃ (MOVE2), or -CF₃ (MOVE3); (iii) perfluorodioxoles having formula : wherein each of Rf3, R f4, Rf5, Rf6, equal to or different from each other, is independently selected from the group consisting of fluorine atom and C1-C6 perfluoroalkyl groups, optionally comprising one or more than one oxygen atom, such as notably -CF₃, -C₂F₅, -C₃F₇, -OCF₃, -OCF₂CF₂OCF₃; in the presence of UV radiation or under heating, provided that the amount of the compound of formula (X-p) is less than 5 wt.% of the amount of the PFPE peroxy. [0046] Optionally, a fluorination step can be performed. [0047] Preferably, said PFPE additive is a salt of a (per)fluoropolyether polymer comprising a (per)fluoropolyether chain [PFPE chain] having two chain ends bonded to opposite sides of said PFPE chain, wherein at least one chain end comprises at least one group selected from: (i) acid group selected from: -COO-, metal salt or with at least one organic group selected from ammonium salt and phosphonium salt; (ii) ammonium group and at least one inorganic or organic counterion. [0048] Preferably, said PFPE additive is in an amount of at least 0.1 wt.% based on the total weight of composition (COMP). [0049] More preferably, said PFPE additive is in an amount from 0.1 to 20.0 wt.%, even more preferably from 0.5 to 15 wt.% and still more preferably from 1 .0 to 12 wt.% based on the total weight of composition (COMP).

[0050] Preferably, in the PFPE additive (i), said acid group is a carboxylic group.

[0051 ] Such carboxylic group can be salified with at least one inorganic metal salt or the organic salt selected from ammonium salt and phosphonium salt.

[0052] Preferably, in the PFPE additive (i), said at least one inorganic metal salt is selected from alkaline metals. More preferably, said alkaline metals are selected in the group comprising sodium, potassium, cesium, lithium, magnesium and calcium.

[0053] Preferably, in the PFPE additive (i), said organic ammonium salt is selected from those of formula: N⁺H(R2i)(R22)(R23) wherein each of R21, R22, R23 is selected from: linear or branched C1-C20 aliphatic chain, optionally containing at least one heteroatom, preferably -O-; or two of R21, R22, R23 together form a 5- or 6- membered aliphatic or aromatic ring, said ring optionally containing at least one heteroatom and/or being optionally substituted by at least one linear or branched alkyl chain comprising from 1 to 10 carbon atoms and optionally containing at least one heteroatom, preferably selected from -O- and -N-, and the third of R21, R22, R23 is as defined above.

[0054] More preferably, said organic ammonium salt is selected from triethanol ammonium, triethyl ammonium, pyridinium, trimethyl ammonium, tributyl ammonium, 1 -methyl imidazolium, di(ethyl)cyclohexyl-ammonium, benz- imidazolium, 1 -benzyl imidazolium.

[0055] Preferably, in the PFPE additive (ii), said ammonium group is selected from those of formula:

§-N⁺(R31 )(R₃₂)(R33) wherein

§ indicates the bond to the (per)fluoropolyether backbone, and each of R31, R32, R33 is selected from: linear or branched C1-C20 aliphatic chain, optionally containing at least one heteroatom, preferably -O-; or two of Rsi , R32, R33 together form a 5- or 6- membered aliphatic or aromatic ring, said ring optionally containing at least one heteroatom and/or being optionally substituted by at least one linear or branched alkyl chain comprising from 1 to 10 carbon atoms and optionally containing at least one heteroatom, preferably selected from -0- and -N-, and the third of R31, R32, R33 is as defined above

[0056] More preferably, said ammonium group is selected from di(methyl)benzyl- ammonium, di(methyl)octyl-ammonium, tri(methyl) ammonium, tri(butyl)ammonium, tri(tert-butyl)ammonium, di(cyclohexane) methylammonium, tri(pentyl)ammonium, di(ethyl)cyclohexylammonium, di- (butyl)methylammonium, di(ethyl)butyl-ammonium, 1-butyl-imidazolium, 1- methylimidazolium, 1-benzyl-imidazolium, benzimidazolium, pyridinium, pyridazinium, pyrimidinium, pyrazinium, 1 ,2,4-triazolium.

[0057] Preferably, in the PFPE additive (ii), said at least one inorganic or organic counterion is selected in the group comprising: Br; I; Cl; BF< , NOs’ , OH; [(CFSSO2)2N]; sulfonate and sulfate.

[0058] Said sulfonate is preferably selected in the group comprising: triflate, nonaflate, mesylate and tosylate.

[0059] Preferably, the PFPE chain of said PFPE additive (i) or (ii) is a partially or fully fluorinated chain [chain (Rf)] comprising, preferably consisting of, repeating units R°, said repeating units being independently selected from the group consisting of:

(i) -CFXO-, wherein X is F or CF3;

(iv) -CF2CF2CF2CF2O-;

[0060] Preferably, chain (Rf) complies with formulae (Rf-I) and (Rf-ll) as defined above.

[0061 ] According to an embodiment, said PFPE additive (i) comprises at one chain end or at both chain ends, a carboxyl group salified with at least one inorganic metal salt. Said at least one inorganic metal salt is as defined above.

[0062] Preferably, said PFPE additive comprises, at one chain end or at both chain ends, a carboxyl group salified with at least one organic ammonium salt. Said at least one organic ammonium salt is as defined above.

[0063] More preferably, said PFPE additive comprises at one chain end a salified carboxyl group as defined herein above and at the other chain end a neutral group.

[0064] Such neutral group is preferably fluorine atom or a perfluorinated alkyl chain comprising 1 to 6 carbon atoms.

[0065] According to this embodiment, the chain end comprising an acid group is preferably bonded to the (per)fluoropolyether backbone complying with formula (Rf) as defined above via a group of formula -CF2- or -CF(CF3)-.

[0066] The PFPE additive (i) can be prepared according to methods known in the art, such as following the procedure disclosed in US 5,000,864 (in the name of Ausimont S.p.A.).

[0067] According to another embodiment, said PFPE additive (ii) comprises at one chain end or both chain ends, an ammonium group and at least one inorganic or organic counterion.

[0068] Preferably, said ammonium group is as defined above.

[0069] Preferably, said at least one inorganic or organic counterion is as defined above.

[0070] According to this second embodiment, the chain end comprising an ammonium group is preferably bonded to the (per)fluoropolyether backbone complying with formula (Rf) as defined above via a group of formula -CF2- or - CF2CH2-.

[0071 ] Also, according to this second embodiment, the chain end comprising an ammonium group is preferably bonded to said sigma bond or group (B1 ) via an alkoxylated chain [chain (R_a)].

[0072] Preferably, said chain (R_a) complies with one of the following formulae (R_a-i) to (R_a-m):

(R_a-i) -(OCH₂CH2)ji-H

(R_a-ii) -[OCH(CH3)CH₂]j2-H

(R_a-m) -[(OCH2CH2)j3-(OCH(CH₃)CH2)j4]j(x)-H wherein j1 and j2, each independently, are an integer from 1 to 10, more preferably from 1 to 5; j3, j4 and j(x) are integers from 1 to 25, and the sum of j3 and j4 is from 2 to 50.

[0073] The PFPE additive (ii) can be prepared according to methods known in the art, such as following the method disclosed in WO 2022/078766 (Solvay Specialty Polymers Italy S.p.A.).

[0074] Preferably, said thickener is in the form of powder having an average particle size (dso) higher than 1 micrometer, more preferably higher than 2 micrometers, and still more preferably higher than 3 micrometers, as measured by laser diffraction particle size analysis as volume particle size distribution.

[0075] Preferably, said thickener is in the form of powder having a dso below 15 micrometers, more preferably below 12 micrometers, and still more preferably below 10 micrometers, as measured by laser diffraction particle size analysis as volume particle size distribution.

[0076] Preferably, said thickener is a fluorinated polymer.

[0077] According to this embodiment, said fluorinated polymer is poly(tetrafluoroethylene) (PTFE).

[0078] Preferably, said thickener is an aromatic polymer. [0079] According to this embodiment, said aromatic polymer has a melting point of at least 150°C.

[0080] Preferably, said aromatic polymer is in the form of powder having a dso measured by laser diffraction particle size analysis as volume particle size distribution, in the range from above 1 micrometer and up to 15 micrometers, and a surface area (determined by gas adsorption using the BET method according to ISO 9277) from 0.5 to less than 5 m²/g.

[0081] Said at least one aromatic polymer is advantageously selected in the group comprising, preferably consisting of:

(a) poly(arylene sulphides) (PAS) polymer;

(b) poly(phenylene oxides) (PPO) polymer;

(c) poly(aryl ether ketone) (PAEK) polymer; and

(d) poly(aryl ether sulfone) (PAES) polymer.

[0082] Preferably, said (a) poly(arylene sulfide) (PAS) is a polymer comprising -(Ar-S)- recurring units, wherein Ar is an arylene group, also called herein recurring unit (RPAs).

[0083] The arylene groups of the PAS can be substituted or unsubstituted.

[0084] Additionally, said PAS can include any isomeric relationship of the sulfide linkages in polymer; e.g., when the arylene group is a phenylene group, the sulfide linkages can be ortho, meta, para, or combinations thereof.

[0085] Preferably, said PAS polymer comprises at least 5, at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, at least 95, at least 98 mol.% of recurring units (RPAs), based on the total number of males in the PAS. According to an embodiment, the PAS consists essentially in recurring units (RPAs).

[0086] Preferably, said PAS polymer is selected from the group consisting of poly(2,4-toluene sulfide), poly(4,4'-biphenylene sulfide), poly(para-phenylene sulfide) (PPS), poly(ortho-phenylene sulfide), poly(meta-phenylene sulfide), poly(xylene sulfide), poly(ethylisopropylphenylene sulfide), poly(tetramethylphenylene sulfide), poly(butylcyclohexylphenylene sulfide), poly(hexyldodecylphenylene sulfide), poly(octadecylphenylene sulfide), poly(phenylphenylene sulfide), poly-(tolylphenylene sulfide), poly(benzylphenylene sulfide) and poly[octyl-4-(3-methylcyclopentyl) phenylene sulfide],

[0087] More preferably, said PAS is a PPS comprising recurring units represented by Formula I:

[0088] Even more preferably, the PPS comprises at least 50 mol. % of recurring units of Formula I, based on the total number of moles in the PPS polymer. For example at least about 60 mol. %, at least about 70 mol. %, at least about 80 mol. %, at least about 90 mol. %, at least about 95 mol. %, at least about 99 mol. % of the recurring units in the PPS are recurring units of Formula I.

[0089] According to an embodiment of the present invention, the PPS polymer is such that about 100 mol. % of the recurring units are recurring units of Formula I. According to this embodiment, the PPS polymer consists essentially of recurring units (RPPs) of Formula I.

[0090] The PAS polymer of the present invention can be obtained by a process known in the art. Reference can notably be made to WO 2015/095362 (Chevron Philipps), WO 2015/177857 (Solvay) and WO 2016/079243 (Solvay).

[0091 ] Preferably, said (b) poly(phenylene oxide) (PPO) polymer comprises recurring units complying with the following formulae (II): wherein

R and R’ , equal to or different from each other, are H, -CHs or -CeHs and n is an integer at least equal to 1 . [0092] Preferably, said (c) poly(aryl ether ketone) (PAEK) polymer is a polymer comprising more than 50 mol% of recurring units (R-PAEK), wherein recurring units (R-PAEK) comprise a Ar — C(O) — Ar'roup, wherein Ar and Ar', equal to or different from each other, are aromatic groups.

[0093] In some embodiments, the poly(aryl ether ketone) (PAEK) comprises at least 60 mol.%, at least 70 mol.%, at least 80 mol.%, at least 90 mol.%, at least 95 mol.%, or at least 99 mol.%, at least 99.5 mol%, or at least 99.9 mol% of recurring units (R-PAEK). As used herein, mol.% is relative to the total number of moles of recurring units in the poly(aryl ether ketone) (PAEK).

[0094] In some embodiments, the recurring units (R-PAEK) are selected from the group consisting of formulae (J-A) to (J-O), herein below:

wherein: each of R', equal to or different from each other, is selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium; and j's an integer from 0 to 4.

[0095] In the recurring unit (R-PAEK), the respective phenylene moieties may independently have 1 ,2-, 1 ,4- or 1 ,3 -linkages to the other moieties different from R'n the recurring unit. Preferably, the phenylene moieties have 1 ,3- or 1 ,4- linkages, more preferably they have 1 ,4-linkage.

[0096] In some embodiments, j'n recurring unit (R-PAEK) is at each occurrence zero. That is to say that the phenylene moieties have no other substituents than those enabling linkage in the main chain of the polymer.

[0097] Preferred recurring units (R-PAEK) are thus selected from those of formulae (J'-A) to (J'-O) herein below:

[0098] In a preferred embodiment, the polyaryletherketone (PAEK) is a polyetheretherketone (PEEK).

[0099] In this embodiment, the polyetheretherketone (PEEK) has recurring units (R- PEEK) represented by either formula (J-A) or (J'-A), preferably recurring unit (R-PEEK) is represented by formula (J'-A).

[00100] According to an embodiment, the composition (C) comprises a plurality of distinct poly(aryl ether ketone) polymers, each poly(aryl ether ketone) polymer having a distinct recurring unit (R-PAEK).

[00101] Preferably, in said (d) poly(aryl ether sulfone) (PAES) polymer, at least 50 mol.% of the recurring units are recurring units of formula (IV): wherein:

(i) each R, equal to or different from each other, is selected from a halogen, an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium;

(ii) each h, equal to or different from each other, is an integer ranging from 0 to 4; and

(iii) T is selected from the group consisting of a bond, a sulfone group [-S(=O)2-], and a group -C(Rj)(Rk)-, where Rj and Rk, equal to or different from each other, are selected from a hydrogen, a halogen, an alkyl, an alkenyl, an alkynyl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium.

[00102] Preferably, Rj and Rk are each a methyl group.

[00103] Preferably at least 60 mol.%, 70 mol.%, 80 mol.%, 90 mol.%, 95 mol.%, 99 mol.%, and most preferably all of recurring units in the poly(aryl ether sulfone) (PAES) are recurring units of formula (IV). As used herein, mol.% is relative to the total number of moles of recurring units in the poly(aryl ether sulfone) (PAES).

[00104] In an embodiment, the poly(aryl ether sulfone) (PAES) is a poly(biphenyl ether sulfone). A poly(biphenyl ether sulfone) polymer is a poly(aryl ether sufone) which comprises a biphenyl moiety. The poly(biphenyl ether sulfone) is also known as polyphenyl sulfone (PPSLI) and for example results from the condensation of 4,4'-dihydroxybiphenyl (biphenol) and 4,4'-dichlorodiphenyl sulfone.

[00105] As used herein, a "poly(biphenyl ether sulfone) (PPSLI)" denotes any polymer of which more than 50 mol.% of the recurring units are recurring units (Rppsu) of formula (IV-A): [00106] Preferably at least 60 mol.%, 70 mol.%, 80 mol.%, 90 mol.%, 95 mol.%, 99 mol.%, and most preferably all of the recurring units in the poly(biphenyl ether sulfone) (PPSLI) are recurring units of formula (IV-A).

[00107] In an embodiment, the poly(aryl ether sulfone) (PAES) is a polyethersulfone (PES).

[00108] As used herein, a "poly(ethersulfone) (PES)" denotes any polymer of which at least 50 mol.% of the recurring units are recurring units of formula (IV-B):

(IV-B)

[00109] Preferably at least 60 mol.%, 70 mol.%, 80 mol.%, 90 mol.%, 95 mol.%, 99 mol.%, and most preferably all of the recurring units in the poly(ethersulfone) (PES) are recurring units of formula (IV-B).

[00110] In an embodiment, the poly(aryl ether sulfone) (PAES) is a polysulfone (PSU). As used herein, a "polysulfone (PSU)" denotes any polymer of which at least 50 mol.% of the recurring units are recurring units of formula (IV-C):

[00111] Preferably at least 60 mol.%, 70 mol.%, 80 mol.%, 90 mol.%, 95 mol.%, 99 mol.%, and most preferably all of the recurring units in the PSU are recurring units of formula (IV-C).

[00112] If required by the final application, composition (COMP) according to the present invention can contain at least one additional ingredient, such as for example those commonly used in lubricant compositions.

[00113] Non-limiting examples of suitable additives are the following: anti rust agents, antioxidants, thermal stabilizers, pour-point depressants, anti-wear agents, including those for high pressures, tracers, rheological modifiers, corrosion inhibitors, pigment, dyestuffs and fillers.

[00114] Each of such at least one additional ingredient can be present in an amount from 0.1 to 15 wt.% based on the total weight of composition (COMP).

[00115] Composition (COMP) is preferably manufactured including PTFE as the filler. Preferably, the amount of PTFE is from 5 to 45 wt.%, more preferably from 10 to 40 wt.%, even more preferably from 20 to 30 wt.% based on the total weight of composition (COMP).

[00116] In a further object, the present invention relates to the use of said composition (COMP) as lubricant for electrical components suitable for use in different applications and industries, such as in particular automotive and electronic industries. Such components include, electrical and electronic components, such - without limitation - electrical connectors, switchgears and circuit breakers.

[00117] In other words, the present invention relates to a method for lubricating at least one electrical or electronic component, preferably selected from electrical connectors, switchgears and circuit breakers, said method comprising applying composition (COMP) as defined above to at least a part of such component.

[00118] In still a further object, the present invention relates to the use of said composition (COMP) as lubricant for mechanical components, suitable for use in the automotive industry, in particular for electric vehicles (EV). Such components include - without limitations - ball bearings.

[00119] In other words, the present invention related to a method for lubricating at least one mechanical component, preferably selected from ball bearings, said method comprising applying composition (COMP) as defined in any one of Claims 1 to 13 to at least a part of such component.

[00120] In still a further object, the present invention relates to the use of composition (COMP) according to the present invention for the manufacture of a grease. [00121] In another object, the present invention relates to a grease comprising composition (COMP) according to the present invention and at least one other ingredient.

[00122] Such grease can be advantageously used as lubricant for electrical, electronic or mechanical components. Examples of such components are provided above and include - without limitation - electrical connectors, switchgears and circuit breakers, as well as ball bearings.

[00123] 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.

[00124] The present invention will be now described in more detail with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the disclosure.

[00125] EXAMPLES

[00126] Materials

[00127] Base grease 1 comprising (amounts are based on the total weight of the base grease):

- 70 wt.% of Fomblin^(R) PFPE M07 [neutral PFPE] having a Mn = 5400 as measured via NMR (commercially available by Solvay Specialty Polymers Italy S.p.A.)

- 30 wt.% of Algoflon^(R) L 203R PTFE as thickener, having a particle size = 5 micrometers (commercially available by Solvay Specialty Polymers Italy S.p.A.)

[00128] Base grease 2 comprising (amounts are based on the total weight of the base grease):

- 70 wt.% of Fomblin^(R) PFPE M30 as described above

- 30 wt.% of PPS M1100 UFP (commercially available by Solvay Specialty Polymers U.S.A., LLC.) [00129] Antirust: Fomblin^(R) DA306 (PFPE Y amide) commercially available from Solvay Specialty Polymers Italy S.p.A.

[00130] Thermal stabilizer: Fomblin^(R) DA410 (bifunctional linear PFPE) - commercially available from Solvay Specialty Polymers Italy S.p.A.

[00131 ] Graphite: TIMREX KS 6 GRAPHITE - 1001 was obtained by Imerys

[00132] Additives:

ADD1 : triflate salt of 1 -butyl imidazolium monofunctional PFPE comprising a backbone of formula -(CF2CF2O)m(CF2O)n- and having a Mn = 2520 g/mol as measured by Nuclear Magnetic Resonance (NMR) Spectroscopy.

ADD2: triflate salt of 1 -butyl imidazolium monofunctional PFPE comprising a backbone of formula -(CF2CF2O)m(CF2O)n- and having a Mn = 4760 g/mol as measured by NMR.

ADD3: branched PFPE (functionality < 0.5) comprising carboxylate end group salified with triethanolamine and having a Mn about 5,000 as measured by NMR.

[00133] Compositions of comparison and according to the present invention were prepared by mixing the base oil 1 mentioned above with the following ingredients in the amounts detailed in Table 1 .

Table 1

(*) comparison [00134] The compositions were evaluated in the tests reported in Table 2.

[00135] Comparative composition 3C(*) was not further tested because the presence of the particles of graphite led to phase separation under harsh test conditions.

Table 2

(*) comparison

[00136] Compositions of comparison and according to the present invention were prepared by mixing the base oil 2 mentioned above with the following ingredients in the amounts detailed in Table 3.

Table 3

(*) comparison

[00137] The compositions were evaluated in the tests reported in Table 4. Table 4

(*) comparison

Claims

1 . A composition [composition (COMP)] comprising:

(A) a (per)fluoropolyether polymer-base oil [PFPE base oil];

(i) acid group selected from:

(ii) ammonium group and at least one inorganic or organic counterion; and

(C) from 0.1 % to 35.0% by weight, preferably from 1.0% to 32.0% by weight, based on 100% by weight of said composition, of at least one thickeners selected from fluorinated polymer and/or aromatic polymer.

2. The composition (COMP) according to Claim 1 , wherein the PFPE base oil is selected from the group comprising:

(A-l I) at least one block copolymer [PFPE copolymer] comprising a first and a second (per)fluoropolyether chain [PFPE chain] each having two chain ends, wherein the first chain end of said first and second PFPE chain comprises a perfluorinated alkyl group and the second chain end of said first and second PFPE chain are bonded to each other via: - at least one first block [block (1)] complying with formula (I): I) n is 0 or an integer from 1 to 3; R1 to R4, each independently, is selected in the group comprising, preferably consisting of, fluorine atom, perfluorinated linear or branched alkyl group having from 1 to 6 carbon atoms, group of formula (II): (II) -(R10)t[C(R11)(R12)-C(R13)(R14)(R15)]z wherein R₁₀ is an oxygen atom, or a bi-/tri-/tetravalent perfluorinated alkyl chain comprising from 1 to 24 carbon atoms optionally interrupted by and/or comprising at least one oxygen atom, t is zero or 1, z is an integer from 1 to 3; R11 to R15, each independently, is selected in the group comprising, preferably consisting of, fluorine atom, perfluorinated linear or branched alkyl group having from 1 to 6 carbon atoms and group of formula (III): -[(A^)a^-(B^)v^-(E^)L^]u^-(C^)-T (III) wherein a^ is zero or 1, v^ is zero or an integer from 1 to 3, L^ is zero or an integer from 1 to 250, u^ is zero or an integer from 1 to 50; A^ is a PFPE chain B^ is a group of formula: -[C(R_1^)(R_2^)-C(R_3^)(R_4^)]- wherein R_1^ to R_4^ each independently has the meaning defined above for each of R1 to R4, E^ is a group of formula -(CR100^R101^CR102^R103^)- wherein R100^ and R101^ are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom, and R_102^ and R_103^ are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom; linear or branched alkyl chain comprising from 1 to 6 carbon atoms, optionally containing at least one heteroatom selected from O, N and S; -OR₂₀₀ wherein R₂₀₀ is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms; or one of R100^ and R101^ and one of R102^ and R103^ are a fluorine atom and the other of R100^ and R101^ and the other of R102^ and R103^ together form a perhalogenated cyclic ring having from 4 to 6 members, optionally comprising heteroatoms, such as oxygen atoms; C^ is a PFPE chain, and T is a perfluorinated alkyl group; - at least one second block [block (2)] complying with formula (IV): -[(CR^1*R^2*CR^3*R^4*)n*-(E)L]- (IV) wherein n* is zero or an integer from 1 to 250, L is zero or an integer from 1 to 250 and the sum of n* and L is 0 or from 1 to 250; R^1* and R^2* are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom, and R^3* and R^4* are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom; linear or branched alkyl chain comprising from 1 to 6 carbon atoms, optionally containing at least one heteroatom selected from 0, N and S; -OR200 wherein R200 is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms; or one of R¹* and R²* and one of R³* and R⁴* are a fluorine atom and the other of R¹* and R²* and the other of R³* and R⁴* together form a perhalogenated cyclic ring having from 4 to 6 members, optionally comprising heteroatoms, such as oxygen atoms;

E has the same meaning provided for E^A above;

- optionally, at least a third block [block (3)] comprising a PFPE chain; with the proviso that: in said PFPE copolymer:

-- at least one of n, n* and L is different from 0;

-- said block (1 ), said block (2) and when present said block (3) are statistically distributed; in said formula (I):

-- at least one of R1 to R4 is a group of formula (II),

-- one of R11 or R12 and one of R13 to R15, is a group of formula (III); in said formula (III) and said formula (IV)

-- the recurring units are statistically distributed, in said formula (III)

-- when a^A is 1 at least one of v^A and L^A is different from 0.

3. The composition (COMP) according to Claim 2, wherein each of the PFPE chain is a partially or fully fluorinated chain [chain (Rf)] comprising, preferably consisting of, repeating units R°, said repeating units being independently selected from the group consisting of:

(i) -CFXO-, wherein X is F or CF3; (ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF3, with the proviso that at least one of X is -F;

(iv) -CF2CF2CF2CF2O-;

(v) -(CF2)W-CFZ-0- wherein w is an integer from 0 to 3 and Z is a group of general formula -O-R(f-a)-Y, wherein R<f-a) is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings : -CFXO- , -CF2CFXO-, -CF2CF2CF2O-, - CF2CF2CF2CF2O-, with each of each of X being independently F or CF3 and Y being a C1-C3 perfluoroalkyl group.

4. The composition (COMP) according to any one of the preceding Claims, wherein said PFPE copolymer has a viscosity of at least 1 ,000 mm²/s, measured at 20°C according to standard methods, such as ASTM D445, or with a dynamical mechanical spectrometer Anton Paar MCR 502 rheometer equipped with parallel plates 25 mm, at 0.1 rad/s and at 25°C.

5. The composition (COMP) according to any one of the preceding Claims, wherein in said PFPE copolymer:

- said first chain end of said first and second PFPE chain comprise a perfluorinated linear alkyl group having from 1 to 3 carbon atoms; and/or

- said first PFPE chain is bonded to said block (1 ) via a sigma bond or a group -(C)- selected from -CF2-, -CF2CF2- or -O-; and/or

- said block (2) is bonded to said second PFPE chain via a sigma bond or a group -(C)- selected from -CF2-, -CF2CF2- or -O-; and/or

- when both said block (1 ) and said block (2) are present, they are linked via a sigma bond; and/or

- the sum of (n + n* + v^A) is from 1 to 15, preferably from 1 to 11 , more preferably from 1 to 9; and/or - the sum of (L+L^) is from 1 to 500, preferably from 2 to 500, more preferably from 2 to 300.

6. The composition (COMP) according to any one of the preceding Claims, wherein said PFPE copolymer comprises a first and a second PFPE chain, each having two chain ends, wherein the first chain end of said first and second PFPE chain comprises a perfluorinated alkyl group and the second chain end of said first and second PFPE chain are bonded to each other via: - at least one block (2) complying with formula (IV): -[(CR^1*R^2*CR^3*R^4*)n*-(E)L]- (IV) wherein n* is an integer from 1 to 250, L is an integer from 1 to 250, and the sum of n* and L is from 1 to 250; R^1* and R^2* are fluorine atom, and R^3* and R^4* are independently selected from halogen atom, more preferably fluorine or chlorine atom; linear or branched alkyl chain comprising from 1 to 6 carbon atoms, optionally containing at least one heteroatom selected from O, N and S; -OR₂₀₀ wherein R₂₀₀ is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms; E is a group of formula -(CR_100^R_101^CR_102^R_103^)- wherein R100^ and R101^ are independently selected from halogen atom, preferably fluorine or chlorine atom, and R102^ and R103^ are independently selected from halogen atom, preferably fluorine or chlorine atom; -OR200 wherein R200 is linear or branched perfluorinated chain comprising from 1 to 6 carbon atoms or a group of formula -CF2OR201 in which R201 is a perfluorinated alkyl chain comprising from 1 to 6 carbon atoms, optionally interrupted by one or more oxygen ether atoms; and

- optionally, at least one block (3) comprising a PFPE chain.

7. The composition (COMP) according to any one of the preceding Claims, wherein said PFPE additive is a salt of a (per)fluoropolyether polymer comprising a (per)fluoropolyether chain [PFPE chain] having two chain ends bonded to opposite sides of said PFPE chain, wherein at least one chain end comprises at least one group selected from:

(i) acid group selected from:

-coo-, each being salified with at least one inorganic metal salt or with at least one organic group selected from ammonium salt and phosphonium salt;

(ii) ammonium group and at least one inorganic or organic counterion.

8. The composition (COMP) according to any one of the preceding Claims, wherein said PFPE additive is in an amount of at least 0.1 wt.% based on the total weight of composition (COMP) and/or in an amount from 0.1 to 20.0 wt.%, even more preferably from 0.5 to 15 wt.% and still more preferably from 1 .0 to 12 wt.% based on the total weight of composition (COMP).

9. The composition (COMP) according to any one of the preceding Claims, wherein in the PFPE additive (i), said acid group is a carboxylic group, preferably salified with at least one:

- inorganic metal salt or

- organic salt selected from ammonium salt and phosphonium salt.

10. The composition (COMP) according to any one of the preceding Claims, wherein in the PFPE additive (ii), said at least one inorganic or organic counterion is selected in the group comprising: Br; I; Cl; BF< , NOs’ , OH; [(CFSSO2)2N]; sulfonate and sulfate.

11 . The composition (COMP) according to any one of the preceding Claims, wherein said thickener is in the form of powder having an average particle size (dso):

- higher than 1 micrometer, as measured by laser diffraction particle size analysis as volume particle size distribution; and/or

- below 15 micrometers, as measured by laser diffraction particle size analysis as volume particle size distribution.

12. The composition (COMP) according to any one of the preceding Claims, wherein said thickener is a fluorinated polymer, preferably poly(tetrafluoroethylene) (PTFE).

13. The composition (COMP) according to any one of the preceding Claims, wherein said thickener is an aromatic polymer, preferably selected in the group comprising, preferably consisting of:

(a) poly(arylene sulphides) (PAS) polymer;

(b) poly(phenylene oxides) (PPO) polymer;

(c) poly(aryl ether ketone) (PAEK) polymer; and

(d) poly(aryl ether sulfone) (PAES) polymer.

14. A method for lubricating at least one electrical or electronic component, preferably selected from electrical connectors, switchgears and circuit breakers, said method comprising applying composition (COMP) according to any one of Claims 1 to 13 to at least a part of such a component.

15. A method for lubricating at least one mechanical component, preferably selected from ball bearings, said method comprising applying composition (COMP) as defined in any one of Claims 1 to 13 to at least a part of such component.

16. A grease comprising composition (COMP) according to any one of Claims 1 to 13 and at least one other ingredient.