Lubricant composition based on perfluorpolyether

Abstract

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

Description

DescriptionLUBRICANT COMPOSITION BASED ON PERFLUORPOLYETHERCross reference to related patent applications

[0001] This application claims priority filed on 13 November 2023 in Europe with Nr. 23209541 , the whole content of this applications being incorporated herein by reference for all purposes.Technical field

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

[0016] 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).

[0017] Such composition needs to show good static dissipation 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).

[0018] 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

[0019] 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 parentheses 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 context;- the prefix "(per)" in the term "(per)fluoropolyether” means that the polyether can be fully or partially fluorinated.

[0020] In a first aspect, the present invention relates to a composition [composition (COMP)] comprising:(A) at least one base oil selected from hydrogenated oil or (per)fluorinated oil;(B) from 0.1 to 20.0 wt.% based on the total weight of composition (COMP) of at least one (per)fluoropolyether polymer [PFPE additive] comprising a (per)fluoropolyether chain [PFPE chain] having two chain ends bonded to opposite sides of said backbone, wherein at least one chain end comprises at least one group selected from: -C(=O)NR1 R2 with Ri and R2 identical or different from each other being selected from hydrogen or linear or branched alkyl chain comprising from 1 to 6 carbon atoms; and / or -CF2C(O)CF3; and the other chain end comprising a neutral group selected from C1-C6 perfluoroalkyl chain;(C) from 0.1 % to 35.0% by weight, preferably from 1 .0% to 32.0% by weight, based on 100% by weight of composition (COMP), of at least one thickener selected from the group comprising: soap thickener, preferably selected from metals soap, complex soap; and non-soap thickeners, preferably selected from polyurea, clay, fumed silica, fluorinated polymer and / or aromatic polymer; and(D) at least one additive in the form of solid particles in an amount from 0.01 to 25 wt.% based on the total weight of the composition (COMP).

[0021] Preferably, the solid particles of the at least one additive (D) are electrically conductive solid particles.

[0022] Surprisingly, the Applicant found that composition (COMP) has excellent thermal and thermo-oxidative stability, while the PFPE additive allows to dissipate the static charges.

[0023] Preferably, said at least one hydrogenated oil is a mineral oil or a synthetic oil, such as polyalphaolefins (PAO) and polyalkylene glycol (PAG); esters; silicon oils; polyphenyl ethers; and the like.

[0024] Preferably, the base oil is selected from (per)fluorinated base oil.

[0025] More preferably, said (per)fluorinated base oil is a (per)fluoropolyether base oil [PFPE base oil],

[0026] Even more preferably, said PFPE base oil is selected from the group comprising:(A-l) (per)fluoropolyether polymer [PFPE polymer] comprising a (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-lI) 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;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)]zwherein R10is 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(R1^)(R2^)-C(R3^)(R4^)]- wherein R1^to R4^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 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 moreoxygen 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): -[(CR1*R2*CR3*R4*)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; R1*and R2*are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom, and R3*and R4*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; -OR200wherein R200is 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^ 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 R1to R4is 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.

[0027] 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 CF3and Y being a C1-C3 perfluoroalkyl group.

[0028] Preferably, chain (Rf) complies with the following formulae (Rf-I) and (Rf-II): (Rf-I) -[(CFX1O)g1(CFX2CFX3O)g2(CF2CF2CF2O)g3(CF2CF2CF2CF2O)g4]- wherein- X1is 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-II) -[(CFX1O)g1(CFX2CFX3O)g2(CF2CF2CF2O)g3(CF2CF2CF2CF2O)g4- (CF(CF3)O)g5(CF2CF(CF3)O)g6]- wherein - X1, X2, X3are 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.

[0029] In a preferred embodiment, chain (Rf) complies with formula (Rf-I) above.

[0030] Preferably, the PFPE base oil is (A-I) the (per)fluoropolyether polymer [PFPE polymer].

[0031] According to this embodiment, said PFPE polymer comprises a linear PFPE chain having two chain ends bonded to opposite sites of said chain, both chain ends comprising a linear perfluorinated alkyl chain having from 1 to 6 carbon atoms, said PFPE polymer having a number average molecular weight from 2000 to 50000, more preferably from 3000 to 20000 as measured by NMR.

[0032] Preferably, said PFPE chain comprises chain (Rf) complying with formula (Rf- I) above.

[0033] Preferably, in said chain (Rf-I), X1is -F.

[0034] Preferably, in said chain (Rf-I), X2and X3are both -F.

[0035] Preferably, in said chain (Rf-I), g1 and g2 are both and independently > 0.

[0036] Preferably, in said chain (Rf-I), g3 and g4 are both 0.

[0037] Preferably, in said chain (Rf-I), g1 +g2 is in the range from 20 to 200.

[0038] Preferably, the PFPE base oil is (A— II) the PFPE copolymer.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Preferably, said perfluorinated alkyl groups are the same from each other.

[0043] 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.

[0044] For example, T and T’, equal to or different from each other, are a fluorine atom or a group selected from -CF3, -CF2CF3, -CF2CF2CF3, -CF(CF3)2. Other halogenated groups, such as for example -CF2CI and -CF2CF2CI, can still be present.

[0045] Preferably, in said first and second PFPE chain, AAand CAare equal or different from each other.

[0046] 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-.

[0047] 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-.

[0048] Preferably, when both said block (1 ) and said block (2) are present, they are linked via a sigma bond.

[0049] Preferably, in the PFPE copolymer, the sum of (n + n* + v^) is from 1 to 15, preferably from 1 to 11, more preferably from 1 to 9.

[0050] Preferably, in the PFPE copolymer, the sum of (L+L^) is from 1 to 500, preferably from 2 to 500, more preferably from 2 to 300,

[0051] 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*R2*CR3*R4*)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; 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 R201is 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 -(CR100^R101^CR102^R103^)- 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; -OR200wherein R200is 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 comprisingfrom 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.

[0052] The viscosity of the PFPE copolymer can be measured using different methods depending on the viscosity of the PFPE copolymer itself.

[0053] Preferably, said PFPE copolymer has a viscosity higher than 1 ,000 mm2 / s at 25°C, more preferably higher than 2,000 mm2 / s at 25°C and even more preferably higher than 3,000 mm2 / s at 25°C.

[0054] Preferably, said PFPE copolymer has a viscosity lower than 5,000,000 mm2 / s at 25°C, more preferably lower than 2,500,000 mm2 / s at 25°C, and even more preferably lower than 2,000,000 mm2 / s at 25°C.

[0055] Preferably, said PFPE copolymer has a viscosity of from 3,000 to 1 ,500,000 mm2 / s at 25°C, more preferably of from 3,500 to 1 ,000,000 mm2 / s at 25°C and even more preferably of from 4,000 to 950,000 mm2 / s at 25°C .

[0056] 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.

[0057] 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.

[0058] 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) whereineach of R21 to R23 and R31 to R33 is independently fluorine atom, perfluorinated alkyl group having from 1 to 3 carbon atoms, R10is 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 (O)] 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 Rfis a C1-C6(per)fluoroalkyl group, preferably -CF3, -C2F5, -C3F7(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 C1- C6perfluoro-alkyls; C5-C6cyclic perfluoro-alkyls, and C2-C6perfluoro-oxy- alkyls, comprising at least one catenary oxygen atom, preferably Rf2 is - CF2CF3 (MOVE1), -CF2CF2OCF3 (MOVE2), or -CF3 (MOVE3);(iii) perfluorodioxoles having formula : wherein each of Rf3, Rf4, 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.

[0059] Optionally, a fluorination step can be performed.

[0060] Preferably, in said PFPE additive, 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; (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 CF3and Y being a C1-C3 perfluoroalkyl group.

[0061] Preferably, chain (Rf) comprises, more preferably consists of, repeating units R° selected from the group consisting of: (i) -CFXO-, wherein X is F or CF3; and / or (ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF3, with the proviso that at least one of X is -CF3.

[0062] Preferably, chain (Rf) complies with the following formulae (Rf-I): (Rf-I) -[(CFX1O)g1(CFX2CFX3O)g2(CF2CF2CF2O)g3(CF2CF2CF2CF2O)g4]- wherein - X1is independently selected from -F and -CF3, - X2, X3, equal or different from each other and at each occurrence, are independently -F, -CF3; - g1 and g2, equal or different from each other, are independently >0, such that g1+g2 is in the range from 2 to 300, preferably from 10 to 250, even more preferably from 15 to 200; the different recurring units being statistically distributed along the chain.

[0063] More preferably, in chain (Rf-I), X2and 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 -CF3.

[0064] Even more preferably, chain (Rf) complies with the following formulae (Rf-II): (Rf-II) -[(CF2O)g1(CFX2CFX3O)g2(CF2CF2CF2O)g3(CF2CF2CF2CF2O)g4- (CF(CF3)O)g5(CF2CF(CF3)O)g6]- wherein - g1, g5 and g6, equal or different from each other, are independently >0, such that g1+g5+g6 is in the range from 2 to 300, preferably from 10 to 250; the different recurring units being statistically distributed along the chain.

[0065] The PFPE additive is preferably provided as a mixture of monofunctional polymer as described above (i.e. comprising at least one chain end comprising at least one group selected from: -C(=O)NR1R2 with R1 and R2 identical or different from each other being selected from hydrogen or linearor branched alkyl chain comprising from 1 to 6 carbon atoms; and / or - CF2C(O)CF3; and the other chain end comprising a neutral group selected from C1-C6perfluoroalkyl chain) in admixture with monofunctional polymer comprising at one chain end a group of formula -C(=O)CF3 or its hydroxylated derivative -C(OH)2CF3 and at the other chain end a neutral group selected from hydrogen or linear or branched alkyl chain comprising from 1 to 6 carbon atoms.

[0066] Preferably, said PFPE additive is in an amount of at least 0.1 wt.% based on the total weight of composition (COMP).

[0067] 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).

[0068] Said thickener is present in an amount of from 0.1 to 45.0 wt.%, preferably from 5 to 40 wt.%, based on the total weight of the composition (COMP). More preferably said thickener is present in an amount of from 0.1 to 35.0 wt%, even more preferably from 1.0 to 32.0 wt% based on the total weight of composition (COMP).

[0069] Preferably, said thickener is in the form of powder having an average particle size (d50) 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.

[0070] Preferably, said thickener is in the form of powder having a d50below 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.

[0071] According to an embodiment, said thickener is selected from soap thickeners.

[0072] Soap thickeners include for example simple soaps that are organic salts of long chain organic acid with alkali metal, such as lithium, calcium, sodium, aluminum, barium, and complex soaps including simple soaps and acomplexing agent. Suitable examples are lithium 12-hydroxystearate, lithium complex, calcium complex and aluminum complex.

[0073] According to an embodiment, said thickener is selected from non-soap thickeners.

[0074] Non-soap thickeners include for example polyurea, clay, fumed silica, fluorinated polymer, and / or aromatic polymer.

[0075] Preferably, said thickener is a fluorinated polymer.

[0076] According to this embodiment, said fluorinated polymer is poly(tetrafluoroethylene) (PTFE).

[0077] Preferably, said thickener is an aromatic polymer.

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

[0079] Preferably, said aromatic polymer is in the form of powder having a d50 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.

[0080] 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.

[0081] 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).

[0082] The arylene groups of the PAS can be substituted or unsubstituted.

[0083] 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.

[0084] 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).

[0085] 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],

[0086] More preferably, said PAS is a PPS comprising recurring units represented by Formula I:

[0087] 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.

[0088] 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.

[0089] 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).

[0090] Preferably, said (b) poly(phenylene oxide) (PPO) polymer comprises recurring units complying with the following formulae (II): wh R and R , equal to or different from each other, are H, -CH3or -C6H5and n is an integer at least equal to 1.

[0091] 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.

[0092] 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).

[0093] 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.

[0094] 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.

[0095] 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.

[0096] Preferred recurring units (R-PAEK) are thus selected from those of formulae (J'-A) to (J'-O) herein below:

[0097] In a preferred embodiment, the polyaryletherketone (PAEK) is a polyetheretherketone (PEEK).

[0098] 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).

[0099] 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).

[0100] 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.

[0101] Preferably, Rj and Rk are each a methyl group.

[0102] 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).

[0103] 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 (PPSU ) and for example results from the condensation of 4,4'-dihydroxybiphenyl (biphenol) and 4,4'-dichlorodiphenyl sulfone.

[0104] 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):

[0105] 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) (PPSU ) are recurring units of formula (IV-A).

[0106] In an embodiment, the poly(aryl ether sulfone) (PAES) is a polyethersulfone (PES).

[0107] 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):

[0108] 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).

[0109] 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):

[0110] 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).

[0111] Preferably, said at least one additive in the form of solid particles is in an amount from 0.05 wt.%, more preferably from 0.10 wt.% and even more preferably from 0.25 wt.% based on the total weight of composition (COMP).

[0112] Preferably, said at least one additive in the form of solid particles is in an amount of less than 12.00 wt.%, more preferably less than 10.00 wt.% andeven more preferably less than 9.50 wt.% based on the total weight of composition (COMP).

[0113] Preferably, said at least one additive in the form of solid particles is in an amount from 0.50 wt.%, more preferably from 1 .00 wt.% and up to 8.00 wt.%, more preferably up to 7.5 wt.% based on the total weight of composition (COMP).

[0114] Preferably, the solid particles of the at least one additive (D) are electrically conductive particles. More preferably, said at least one additive (D) is selected from electrically conductive carbon-based particles and transition metal particles. More preferably, said at least one additive in the form of solid particles is selected from: graphite, carbon black and metals, such as silver and copper. Graphite is particularly preferred.

[0115] 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.

[0116] 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.

[0117] 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). The total amount of such additional ingredients in the composition (COMP) is typically within the range of from 0.1 to 25 wt.% based on the total weight of composition (COMP).

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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 above to at least a part of such component.

[0122] 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.

[0123] In another object, the present invention relates to a grease comprising composition (COMP) according to the present invention and at least one other ingredient.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] EXAMPLES

[0128] Materials

[0129] 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 (Solvay Specialty Polymers Italy S.p.A.) Base grease 2 comprising (amounts are based on the total weight of the base grease): - 72.5 wt.% of Fomblin(R)PFPE M15 [neutral PFPE] having a Mn of 9700 as measured via NMR (commercially available by Solvay Specialty Polymers Italy S.p.A.) - 27.5 wt% of PPS Ryton(R)M1100 UFP as thickener

[0130] Graphite: TIMREX KS 6 GRAPHITE - 1001 was obtained by Imerys

[0131] Additives: ADD1 - mixture of functional PFPE of formula: F3CO(CF2CF(CF3)O)n(CF2O)m(CF(CF3)O)rCF2T with T being -CONH2 (30 wt.%) or -COCF3 (or its hydroxylated derivative - 70 wt.%), the ratio n / (m+r) = 15 and number average molecular weight (Mn) about 2600 g / mol as as measured by Nuclear Magnetic Resonance Spectroscopy (NMR), commercially available from Solvay Specialty Polymers Italy S.p.A..

[0132] Preparation with base grease 1 Compositions of comparison and according to the present invention were prepared by mixing the base grease 1 mentioned above with the following ingredients in the amounts (expressed as wt.%) detailed in Table 1.Table 1(*) comparison

[0133] The compositions were evaluated in the tests reported in Table 2.Table 2(*) comparison n / p = not performed

[0134] Preparation with base grease 2Composition according to the present invention was prepared by mixing the base grease 2 mentioned above with the following ingredients in the amounts (expressed as wt.%) detailed in Table 3.Table 3(*) comparison

[0135] The compositions were evaluated in the tests reported in Table 4.Table 4

Claims

Claims1 . A composition [composition (COMP)] comprising:(A) at least one base oil selected from hydrogenated oil or (per)fluorinated oil;(B) from 0.1 to 20.0 wt.% based on the total weight of composition (COMP) of at least one (per)fluoropolyether polymer [PFPE additive] comprising a (per)fluoropolyether chain [PFPE chain] having two chain ends bonded to opposite sides of said backbone, wherein at least one chain end comprises at least one group selected from: -C(=O)NRI R2 with R1 and R2 identical or different from each other being selected from hydrogen or linear or branched alkyl chain comprising from 1 to 6 carbon atoms; and / or -CF2C(O)CF3; and the other chain end comprising a neutral group selected from C1-C6 perfluoroalkyl chain.(C) from 0.1 % to 45.0% by weight, based on 100% by weight of composition (COMP), of at least one thickener selected from the group comprising: soap thickener, preferably selected from metals soap, complex soap; and non-soap thickeners, preferably selected from polyurea, clay, fumed silica, fluorinated polymer and / or aromatic polymer; and(D) at least one additive in the form of solid particles in an amount from 0.01 to 25 wt.% based on the total weight of the composition (COMP).

2. The composition (COMP) according to Claim 1 , wherein the base oil is selected from (per)fluorinated base oil, preferably selected from (per)fluoropolyether polymer [PFPE base oil],3. The composition (COMP) according to Claim 2, wherein said PFPE base oil is selected from the group comprising:(A-l) (per)fluoropolyether polymer [PFPE polymer] comprising a (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 polymerhaving a number average molecular weight from 500 to 100000, preferably from 2000 to 50000 as measured by NMR; or (A-II) 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):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 R10is 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(R1^)(R2^)-C(R3^)(R4^)]- wherein R1^ to R4^ 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 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; -OR200wherein R200is 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): -[(CR1*R2*CR3*R4*)n*-(E)L]- (IV) whereinn* 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; R1*and R2*are independently selected from hydrogen atom, halogen atom, more preferably fluorine or chlorine atom, and R3*and R4*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; -OR200wherein R200is 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^ 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 R1to R4is 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 aAis 1 at least one of vAand LAis different from 0.

4. The composition (COMP) according to Claim 3, wherein each of the PFPE chains 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.

5. The composition (COMP) according to Claim 4, wherein each of the PFPE chains comprises chain (Rf) complying with formula (Rf-I):(Rf-I)-[(CFX10)g1 (CFX2CFX3O)g2(CF2CF2CF2O)g3(CF2CF2CF2CF2O)g4]- wherein- X1is 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 statisticallydistributed along the chain.

6. The composition (COMP) according to any one of the preceding Claims, wherein said PFPE base oil is (A-l) the (per)fluoropolyether polymer [PFPE polymer],7. The composition (COMP) according to Claim 6, wherein said PFPE base oil is a PFPE polymer comprising a linear PFPE chain having two chain ends bonded to opposite sites of said chain, both chain ends comprising a linear perfluorinated alkyl chain having from 1 to 6 carbon atoms, said PFPE polymer having a number average molecular weight from 2000 to 50000, more preferably from 3000 to 20000 as measured by NMR.

8. The composition (COMP) according to any one of the preceding Claims, wherein, in said PFPE additive, 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; and / or(ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF3, with the proviso that at least one of X is -CF3.

9. The composition (COMP) according to any one of the preceding Claims, wherein said PFPE additive is a mixture of (1 ) monofunctional polymer comprising a branched PFPE chain having at least one chain end comprising at least one group selected from: -C(=O)NR1R2 with R1 and R2 identical or different from each other being selected from hydrogen or linear or branched alkyl chain comprising from 1 to 6 carbon atoms; and / or -CF2C(O)CF3; and the other chain end comprising a neutral group selected from C1-C6 perfluoroalkyl chain; and (2) monofunctional polymer comprising a branched PFPE chain having at one chain end a group of formula -C(=O)CF3 or its hydroxylated derivative -C(OH)2CF3 and at the other chain end a neutral group selected fromhydrogen or linear or branched alkyl chain comprising from 1 to 6 carbon atoms.

10. The composition (COMP) according to any one of the preceding Claims, wherein said PFPE additive is in an amount of from 0.5 to 15 wt.%, preferably from 1 .0 to 12 wt.%, based on the total weight of composition (COMP).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 (d50):- 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 toany 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.

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