Copolymers containing (per)fluoropolyether chains

Abstract

The present patent application relates to block copolymers containing (per)fluoropolyether chains which are useful as lubricants and which are characterized by an increased viscosity.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED PATENT APPLICATIONS This application claims priority to European Patent Application No. 21183081.5, filed July 1, 2021, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present patent application relates to copolymers containing (per)fluoropolyether chains, characterized by an increased viscosity. [Background technology]

[0003] Lubrication is a critical aspect of maintaining machinery in proper operating condition. Machine elements such as bearings, pins, shafts, gears and joints require proper lubrication between their moving surfaces to reduce friction, prevent contamination, reduce wear and dissipate heat. Improper lubrication can lead to premature part wear and component or system failure.

[0004] (Per)fluoropolyethers (hereinafter referred to as "PFPE polymers") have been known for a long time as base oils or as additives in several lubricating applications.

[0005] Several syntheses of PFPE polymers have been disclosed in the art. The first synthesis of an unspecified mixture of perfluorinated polyethers was reported in 1953, where an oily product was obtained during the photo-oligomerization of hexafluoropropene. Since then, a large number of different perfluorinated polyethers have been synthesized and described in the literature.

[0006] U.S. Patent No. 4,500,739 (in the name of Montedison) discloses the reaction of peroxide PFPEs with--among others--perfluorobutadiene (a Group II fluoroolefin). Example 4 discloses the reaction of a large excess of perfluorinated bis-olefins with perfluorobutadiene, resulting in pendant unsaturated groups along the polymer chain so that the reaction can proceed further in the presence of hexamethylenediamine.

[0007] US Patent No. 8,258,090 B2 (in the name of Solvay Solexis SpA) describes a compound of the formula: (I) TO-[AB]z-[A'-B']z'-AT [In the formula, T and T' are C 1~3 Perfluoroalkyl or C 1~6 is alkyl, A and A are perfluoropolyether chains, B is derived from two different olefins, at least one of which has the formula: (Ia) -[(CR1R2-CR3R4) j -(CR5R6-CR7R8) j’ ]- (where: j is 1 to 5, j' is 0 to 4, and the sum of j+j' is 2 to 5, R1 to R8 are halogen, H, C 1~6 (Per)Haloalkyl, C 1~6 Alkyl, C 1~6 oxy(per)fluoroalkyl; z is 2 or more, z' is an integer, and the sum of z and z' is such that the number average molecular weight of the polymer of formula (I) is in the range of 500 to 500,000. which are homopolymerizable by a radical route; B' is (Ia), except that at least one of R1 to R8 has a different meaning than in B. discloses a fluorinated lubricant. This patent discloses that block copolymers characterized by a linear backbone, in other words unbranched, can be obtained from the group of formula B.

[0008] Polymers obtained using PFPE polymer units have been disclosed in the art. Crosslinked fluoroelastomers are among them. In this regard, SPKrukovsky et al.-J of Fluorine Chemistry 96(1999)31-33-disclosed the copolymerization of perfluoroalkylene oxides containing peroxide groups in the chain with perfluorodivinyl ethers under UV radiation and heating to provide crosslinked polymers, said to be elastomers. This publication does not disclose any amounts of reactants, nor does it address the preparation of polymers suitable for use in lubricating oils. Summary of the Invention

[0009] While recent research and development has focused on mono- and / or di-functional (per)fluoropolyether (PFPE) polymers, the Applicant has realized that a need remains to provide neutral PFPE polymers that can be used as lubricants.

[0010] Applicant was faced with the problem of providing new neutral PFPE polymers characterized by a low glass transition temperature (Tg) and also an increased viscosity (as measured by complex viscosity at 25° C. at 0.1 rad / s) while remaining in a liquid state at room temperature.

[0011] The Applicant has surprisingly found that neutral branched (per)fluoropolyether polymers characterized by an increase in viscosity, due to an increase in number average molecular weight, can be provided by a process that is easy to carry out on an industrial scale.

[0012] Advantageously, the present process makes it possible to produce neutral (per)fluoropolyether polymers with high thermal stability while maintaining low glass transition temperatures and increasing viscosity index (ASTM D2270) so that such polymers are particularly useful as lubricants in harsh environments, such as, for example, applications requiring a wide range of operating temperatures or high heat generation.

[0013] In a first aspect, the present invention provides a method for producing a poly(per)fluoropolyether) chain [PFPE chain] having two chain ends, each having two chain ends, wherein both said chain ends comprise a perfluorinated alkyl group, and wherein a first chain end of said first and second PFPE chains comprises a perfluorinated alkyl group and a second chain end of said first and second PFPE chains comprises a perfluorinated alkyl group, and wherein (I) -[AB]- linked together via a block of Where: (A) is a PFPE chain, (B) is represented by the following formula (II): [ka] This is the part that follows: Where: n is an integer from 1 to 3; R1 to R4 each independently represent a fluorine atom, a linear or branched perfluorinated alkyl group having 1 to 6 carbon atoms, or a group represented by formula (III): (III) -(R 10 ) t [C(R 11 )(R 12 )-C(R 13 )(R 14 )(R 15 )] z is selected from the group including, and preferably consisting of, the groups Where: R 10 is an oxygen atom or a di / tri / tetravalent perfluorinated alkyl chain containing 1 to 24 carbon atoms, optionally interrupted and / or containing at least one oxygen atom; t is zero or one; z is an integer from 1 to 3; R 11 ~R 15 each independently represents a fluorine atom, a perfluorinated linear or branched alkyl group having 1 to 6 carbon atoms, and a group of formula (IV): -[(A ∧ ) a -(B ∧ ) v ]-(C ∧ )-T (IV), Where: A ∧ is a PFPE chain, a is zero or one; v is zero or an integer from 1 to 3; B ∧ is the formula -[C(R 1∧ )(R 2∧ )-C(R 3∧ )(R 4∧ )]- Based on Here, R 1∧ ~R 4∧ each independently has the meaning defined above for R1 to R4, C ∧ is a PFPE chain, T is a perfluorinated alkyl group; A block copolymer [copolymer (P)]; (In the formula, ‥ The A and B in formula (I) and the A in formula (IV) ∧ and B. ∧ is statistically distributed, At least one of R1 to R4 is a group represented by formula (III), ‥ R 11 or R 12 One of and R 13 ~R 15 is a group of formula (IV) where a is 1, ‥ (B+B ∧ ) is 1 to 15 Concerning the copolymer (P).

[0014] In a second aspect, the present invention relates to a method for the preparation of a copolymer (P) as defined above [method (P)], said method comprising the following steps: a) dissolving at least one peroxide (per)fluoropolyether polymer [PFPEperoxy] in a solution of a compound of formula (III-p): [ka] (In the formula, R 21 ~R 23 and R 31 ~R 33 each independently represents a fluorine atom, a linear or branched perfluorinated alkyl group having 1 to 6 carbon atoms, R 10 is an oxygen atom, a linear or branched perfluorinated alkyl group containing 1 to 24 carbon atoms, optionally interrupted and / or containing at least one oxygen atom; t is zero or one, preferably one; Each of z* and z** is independently 1 or 2. with at least one perfluorinated compound of Where: the amount of the compound of formula (III-p) is less than 5% by weight of the amount of PFPE peroxy; b) reacting a PFPE peroxy with a compound of formula (III) in the presence of UV radiation or heat; c) fluorination, thus obtaining said copolymer (P). The present invention relates to a method comprising the steps of:

[0015] In the process according to the invention, it is important that the number of equivalents of unsaturation of formula (III-p) is appropriately selected to be lower than the moles of peroxide units in the PFPE peroxy, so that a branched block copolymer (P) is obtained that does not contain unsaturation as pendant groups (also called "functional groups").

[0016] The copolymer (P) advantageously does not contain pendant groups containing any moiety capable of undergoing further chemical reactions. In particular, the copolymer (P) does not contain unsaturated moieties as pendant groups.

[0017] In a third aspect, the present invention relates to a copolymer (P) obtainable by the process (P) described above.

[0018] It will be clear to the skilled person that the copolymer (P) according to the invention is obtained at the end of step (c) of the process (P) as a mixture, although a purification step can be carried out after step (c).

[0019] Thus, in a further aspect, the present invention relates to a mixture [mixture (P)] comprising two or more copolymers (P) as defined above.

[0020] It will be clear to the skilled person that the mixture (P) is obtained by the method (P) as described above.

[0021] Advantageously, said mixture (P) can be subjected to one or more purification steps (also called "fractionation" steps) in order to obtain distinct copolymers (P) characterized by different viscosities.

[0022] In a further aspect, the present invention relates to a method for lubricating at least one surface of at least one article, said method comprising contacting said at least one surface with said copolymer (P) or said mixture (P). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] For purposes of this description and the following claims: - the use of parentheses around symbols or numbers specifying a formula, such as in expressions such as "polymer (P)", has the sole purpose of better distinguishing the symbols or numbers from the rest of the text, and therefore said parentheses may also be omitted; - the acronym "PFPE" stands for "(Per)Fluoropolyether" and, when used as a noun, is intended to mean either the singular or the plural, depending on the context; - the term "(per)fluoropolyether" is intended to denote fully or partially fluorinated polyether polymers.

[0024] Preferably, in the copolymer (P), the first PFPE chain, the second PFPE chain, A, A ∧ , C ∧ are the same or different from each other.

[0025] Preferably, the perfluorinated alkyl groups are the same or different from each other.

[0026] Preferably, the perfluorinated alkyl group is a linear perfluoroalkyl group containing from 1 to 3 carbon atoms.

[0027] Preferably, in the copolymer (P), the at least one first PFPE chain is linked to the at least one block of formula (I) via a sigma bond or a group selected from -CF2-, -CF2CF2- or -O-.

[0028] Preferably, in the copolymer (P), said second PFPE chain is linked to at least one block of formula (I) via a sigma bond or a group selected from -CF2-, -CF2CF2- or -O-.

[0029] Preferably, in the copolymer (P), (A) and (B) in formula (I) are linked via a sigma bond or a group selected from -O-, -CF2- or -CF2CF2-.

[0030] Preferably, in the copolymer (P), the first PFPE chain, the second PFPE chain, A in formula (I) and the A in formula (IV) ∧ and C ∧ Each of the (Rf-i) -CFXO- (wherein X is F or CF3); (Rf-ii) -CFXCFXO- (wherein X, equal or different at each occurrence, is F or CF3, provided that at least one of X is -F); (Rf-iii) -CF2CF2CW2O- (wherein each of W, equal to or different from each other, is F, Cl, or H); (Rf-iv) -CF2CF2CF2CF2O-; (Rf-v) -(CF2) j -CFZ-O- (wherein j is an integer of 0 to 3, and Z is a group represented by the general formula -OR (f-a) -T group, where R (f-a) is a fluoropolyoxyalkene chain containing 0 to 10 repeat units, said repeat units being selected from the following: -CFXO-, -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, where each X is independently F or CF3, and T is a C1 to C3 perfluoroalkyl group. A partially or fully fluorinated chain [Chain (Rf)] comprising, preferably consisting of, repeat units independently selected from the group consisting of:

[0031] Preferably, the chain (R f ) is expressed by the following formula: (R f -I) -[(CFX 1 O) g1 (CFX 2 CFX 3 O) g2 (CF2CF2CF2O) g3 (CF2CF2CF2CF2O) g4 ]- (In the formula, -X 1 is independently selected from -F and -CF3; - X, which are equal or different from each other and for each occurrence 2 , X 3 are independently -F, -CF3, with the proviso that at least one X is -F; - g1, g2, g3, and g4, which are equal to or different from each other, are independently integers equal to or greater than 0, such that g1+g2+g3+g4 is in the range of 2 to 1000; if at least two of g1, g2, g3, and g4 are different from zero, the different repeat units are generally statistically distributed along the chain. Follow.

[0032] More preferably, the chain (R f ) is the formula: (R f -IIA) -[(CF2CF2O) a1 (CF2O) a2 ]- (In the formula: - a1 and a2 are independently integers equal to or greater than 0, such that the number average molecular weight is between 1,000 and 100,000; a1 and a2 are both preferably different from zero, the ratio a1 / a2 being preferably comprised between 0.1 and 10); (R f -IIB) -[(CF2CF2O) b1 (CF2O) b2 (CF(CF3)O) b3 (CF2CF(CF3)O) b4 ]- (In the formula: b1, b2, b3, and b4 are independently integers of 0 or more such that the number average molecular weight is 1,000 to 100,000; preferably, b1 is 0, b2, b3, and b4 are greater than 0, and the ratio b4 / (b2+b3) is 1 or more; (R f -IIC) -[(CF2CF2O) c1 (CF2O) c2 (CF2(CF2) cw CF2O) c3 ]- (In the formula: cw=1 or 2; c1, c2, and c3 are integers equal to or greater than 0, selected such that the number average molecular weight is between 1,000 and 100,000; preferably c1, c2, and c3 are all greater than 0, and the ratio c3 / (c1+c2) is generally less than 0.2. The chain is selected from:

[0033] Even more preferably, the chain (R f ) is herein represented by the following formula (R f -III): (R f -III) -[(CF2CF2O) a1 (CF2O) a2 ]- (In the formula: - a1 and a2 are integers greater than 0 such that the number average molecular weight is 1,000 to 100,000, and the ratio a1 / a2 is generally 0.1 to 10, more preferably 0.2 to 5. Follow.

[0034] Preferably, in formula (II), n is an integer equal to 1 or 2, more preferably equal to 1.

[0035] Preferably, in formula (II), at least one of the substituents R1 to R4 is a group of formula (III), and the other substituents are each independently selected from a fluorine atom or a perfluorinated alkyl chain having 1 to 3 carbon atoms, more preferably a fluorine atom or a perfluorinated alkyl having 1 carbon atom.

[0036] According to one embodiment, in formula (III), t is 0.

[0037] According to another embodiment, in formula (III), t is 1, R 10 is the following formula: (R 10 -i) -(CF2) d (O) e (CF2O) f R CF (O) e* (CF2) d* (CF2O) f* (In the formula, Each of d, d*, e, e*, f, and f* is independently zero or 1; R CFis a perfluoroalkyl chain containing 1 to 12, preferably 1 to 8, carbon atoms, optionally interrupted by one or more oxygen atoms; (R 10 -ii) -O-(C3F6O) h -(CF2) i -(C3F6O) j -O- (In the formula, h=j, h+j is 2 to 6, and i is 2 to 6.) Follow one of the following:

[0038] According to this embodiment, preferably R 10 is the expression: (R 10 -i) -(CF2) d (O) e (CF2O) f R CF (O) e* (CF2) d* (CF2O) f* (In the formula, d, f, d* and f* are zero; e and e* are 1, R CF is a linear perfluoroalkyl chain containing 1 to 10, preferably 1 to 8, carbon atoms. Follow.

[0039] Preferably, in formula (III), z is equal to 1 and R 10 is an oxygen atom or a divalent perfluorinated alkyl chain containing 1 to 24 carbon atoms, optionally interrupted and / or containing at least one oxygen atom.

[0040] Preferably, in formula (III), the substituent R 11 and R 12 is a group of formula (IV), and the other substituent is selected from a fluorine atom or a perfluorinated alkyl chain having 1 to 3 carbon atoms, more preferably a fluorine atom or a perfluorinated alkyl chain having 1 carbon atom.

[0041] Preferably, in formula (III), the substituent R 13 ~R 15 is a group of formula (IV) and the other two substituents are independently selected from a fluorine atom or a perfluorinated alkyl chain having 1 to 3 carbon atoms, more preferably a fluorine atom or a perfluorinated alkyl chain having 1 carbon atom. More preferably, the two substituents are the same and are fluorine atoms.

[0042] Preferably, in formula (IV), a is 1, v is 1, and B ∧ is the formula -[C(R 1∧ )(R 2∧ )-C(R 3∧ )(R 4∧ )](where R 1∧ ~R 4∧ are each independently the same as each of R1 to R4).

[0043] Preferably, the copolymer (P) is characterized by a complex viscosity, measured at 0.1 rad / s and at 25° C., of 10 Pa*s to 5000 Pa*s.

[0044] According to the invention, said copolymer (P) is obtained by the process (P) as described above.

[0045] Prior to step (a), the PFPE peroxy may be subjected to partial reduction of the peroxide bonds, for example by chemical reduction or by UV treatment or heat treatment.

[0046] Preferably, said PFPE peroxy is a peroxide (per)fluoropolyether polymer comprising a (per)fluoropolyether chain having two chain ends, each of said chain ends comprising a (per)fluorinated alkyl chain having 1-3 carbon atoms and optionally containing one or more chlorine atoms or functional end groups selected from acyl fluorides, fluoroformates and ketones, said chain ends being attached to opposite sides of said (per)fluoropolyether chain, said (per)fluoropolyether chain comprising, preferably consisting of, repeat units independently selected from the group consisting of formulae (Rf-i) to (Rf-v) as defined above, and having a peroxide content (PO), defined as grams of active oxygen (Mw=16) in 100 g of PFPE peroxy, of 0.1-4, preferably 0.1-3.5.

[0047] Preferably, in said compound of formula (III-p), when t is 1, 2, 3 or 4 unsaturated moieties are R 10 are bonded to the same or different atoms, preferably carbon atoms, belonging to the

[0048] Preferably, said at least one compound of formula (III-p) has the following formula: CF2=CF(R 10 ) t CF=CF2 in accordance with Where: t is zero or one; R 10 is the following formula; (R 10 -i) -(CF2) d (O) e (CF2O) f R CF (O) e* (CF2) d* (CF2O) f* (In the formula, Each of d, d*, e, e*, f, and f* is independently zero or 1; R CFis a perfluoroalkyl chain containing 1 to 12, preferably 1 to 8, carbon atoms, optionally interrupted by one or more oxygen atoms. (R 10 -ii) -O-(C3F6O) h -(CF2) i -(C3F6O) j -O- (In the formula, h=j, h+j is 2 to 6, and i is 2 to 6.) Follow one of the following:

[0049] Preferably, said compound of formula (III-p) is CF2=CFCF=CF2 CF2=CFOCF=CF2 CF2=CFCF2OCF2CF=CF2 CF2=CFO-(CF2)3CF=CF2 CF2=CFCF2O(CF2)3OCF2-CF=CF2 CF2=CFCF2CF=CF2 CF2=CF(CF2)2CF=CF2 CF2=CF(CF2)3CF=CF2 CF2=CF(CF2)4CF=CF2 CF2=CFOCF2OCF=CF2 CF2 = CFO(CF2)2OCF = CF2 CF2 = CFO(CF2)3OCF = CF2 CF2=CFO(CF2)4OCF=CF2 CF2=CF(CF2)2OCF=CF2 CF2=CF(CF2)3OCF=CF2 CF2=CF(CF2)4OCF=CF2 CF2=CFCF2O(CF2)2OCF2O-CF=CF2 CF2=CFCF2O(CF2)3OCF2O-CF=CF2 CF2=CFCF2O(CF2)4OCF2OCF=CF2 CF2=CFCF2O(CF2)6OCF2CF=CF2 CF2=CFO-CF2O-(CF2)2O-CF2O-CF=CF2 CF2=CFO-CF2O-(CF2)3O-CF2O-CF=CF2 CF2=CFO-CF2O-(CF2)4O-CF2O-CF=CF2 CF2=CFO-(CF2O)6-CF=CF2 CF2=CFO-(CF2CF2O)2-CF=CF2 CF2=CFO-(CF2CF2O)2-CF2OCF=CF2 CF2=CFO(C3F6O) h -(CF2) i -(C3F6O) j -OCF=CF2 (In the formula, h and j are the same, the sum of them is 2 to 6, and i is 2 to 6.) and more preferably selected from the group consisting of:

[0050] According to a particularly preferred embodiment, said at least one compound of formula (III-p) has the following formula: CF2=CF(R 10 ) t CF=CF2 (wherein t is 1) in accordance with R 10 is the expression: (R 10 -i) -(CF2) d (O) e (CF2O) f R CF (O) e* (CF2) d* (CF2O) f* (In the formula, d, f, d* and f* are zero; e and e* are 1, R CF is a linear perfluoroalkyl chain containing 1 to 10, preferably 1 to 8, carbon atoms. Follow.

[0051] Preferably, in step (a), the amount of compound of formula (III-p) is less than 3% by weight, even more preferably less than 1% by weight of PFPE peroxy.

[0052] As the reaction proceeds and copolymer (P) is obtained, the unsaturated moieties in the compound of formula (III-p) become saturated moieties in copolymer (P), so that the substituent R 21 ~R 23 are the substituents R1 to R3 in the formula (III) of the copolymer (P), and the substituents R 31 is the substituent R in formula (III) 11 or R 12 and the substituent R 32 and R 33 is the substituent R in formula (III) of the copolymer (P) 13 ~R 15 It will be readily understood by those skilled in the art that

[0053] Step (a) and step (b) may be carried out in the presence of a fluorinated solvent, preferably selected from the group comprising perfluorocarbons, hydrofluorocarbons, perfluoropolyethers, hydrofluoropolyethers.

[0054] Preferably, step (b) is carried out in the presence of UV radiation for a period of time comprised between 2 and 60 hours.

[0055] Preferably, step (b) is carried out in the presence of UV radiation at a temperature between -60°C and +60°C, more preferably between -20°C and +40°C, even more preferably between 0°C and 30°C.

[0056] Alternatively, step (b) can be carried out under thermal treatment, preferably by heating at a temperature between 100°C and 250°C.

[0057] It will be clear to the skilled person that the polymer obtained at the end of step (b) has a peroxide content (PO) lower than 0.05, preferably lower than 0.001.

[0058] Preferably, said step (c) is carried out by treatment with fluorine in the presence of a stream of anhydrous nitrogen.

[0059] Preferably, said process (P) comprises, after step (c), a step (d) of solvent removal and / or a fractionation step (e).

[0060] Said step (d) of removing the solvent may be carried out by evaporation, for example by distillation under vacuum.

[0061] Said step (e) of fractionation can be carried out by solvent extraction using supercritical CO2, hexafluoroxylene or hydrofluorocarbons and mixtures thereof as solvents when the fractionation step is carried out by precipitation fractionation. Supercritical CO2 is preferred.

[0062] It will be clear to the skilled person that, as explained above, a purification step can be carried out after step (c) or step (d), resulting in obtaining the copolymer (P) according to the invention at the end of step (c) or of step (d) of the process (P) as a mixture (P) in which copolymers (P) characterized by different viscosities and / or molecular weights and / or substituents are present.

[0063] The copolymers (P) are advantageously used as lubricants, especially for applications in harsh environments, for example subjected to a wide range of operating temperatures.

[0064] The copolymer (P) or mixture (P) can be used as such or in admixture with additives known to those skilled in the art of lubrication, resulting in a composition [composition (CL)].

[0065] For example, the composition (CL) may comprise other suitable lubricating oils as base oils, such base oils being selected from the group comprising partially fluorinated, fully fluorinated and hydrogenated base oils, provided that said base oils are capable of forming a solution with the copolymer (P).

[0066] Non-limiting examples of fully fluorinated lubricant base oils are those identified as compounds (1)-(8) in EP 2100909 A (SOLVAY SOLEXIS SpA).

[0067] For example, suitable additives are selected from thickeners, rust inhibitors, antioxidants, heat stabilizers, pour point depressants, high pressure and the like, anti-wear agents, dispersants, tracers, dyes, talc and inorganic fillers.

[0068] Examples of thickening agents are talc, silica, boron nitride, polyurea, alkali or alkaline earth metal terephthalates, calcium and lithium soaps and their complexes, and PTFE (polytetrafluoroethylene); among them, PTFE is preferred.

[0069] Examples of dispersants are, for example, surfactants, preferably non-ionic surfactants, more preferably (per)fluoropolyether surfactants and (per)fluoroalkyl surfactants.

[0070] If required by the application, a solvent may also be used.

[0071] Examples of solvents are fluorinated or partially fluorinated solvents, such as Galden® PFPE, Novec® HFE, and the like, as well as other organic solvents such as fluoroalkanes, fluoroaromatics, fluoroalkyl ethers, fluoroalkylamines, fluoroalcohols, ketones such as methyl ethyl ketone, alcohols such as isopropyl alcohol, esters such as butyl acetate, hydrofluorocarbons, and the like.

[0072] The articles that can benefit from the lubricant properties of the copolymer (P), the mixture (P) or the composition (CL) according to the invention are not particularly limited.

[0073] The article preferably comprises at least one metal surface.

[0074] Examples of said articles are rotating machines, such as pumps for use in oil and gas applications, steam turbines and gas turbines, such as electric submersible pumps, etc.; electrical connectors; bearings of fan clutches or cooling fans; or heavy truck automatic clutches, more particularly bearings of said clutches.

[0075] The copolymers (P), the mixtures (P) or the compositions (CL) according to the invention can advantageously be used as damper fluids in damping devices.

[0076] Thus, in a further aspect, the present invention relates to a method for the cancellation of vibrations and / or shocks in a device, said method comprising providing an apparatus comprising a damping device, said damping device comprising at least one copolymer (P), mixture (P) or composition (CL) as defined above.

[0077] To the extent that the disclosures of any patents, patent applications, and publications incorporated herein by reference conflict with the statements in this application to the extent that a term may be unclear, the statements herein shall control.

[0078] The present invention will now be described with reference to the following examples, the purposes of which are illustrative only and are not intended to limit the scope of the invention.

[0079] Experimental section raw materials formula TO-(CF2CF2O) m (CF2O) n (O) h -T' Number average molecular weight (M n )=48600 g / mol, m / n=1.0 and PO=1.65% T, T'=-CF3(83%), -C(=O)F(6%), -CF2C(=O)F(11%) The peroxide perfluoropolyether oil having the formula was obtained from Solvay Specialty Polymers Italy SpA.

[0080] Galden® HT200 was obtained from Solvay Specialty Polymers Italy SpA.

[0081] Perfluoro(bis vinyl ether) (PBVE) was obtained from Anles Ltd.

[0082] Hexafluorobenzene was obtained from Sigma Aldrich.

[0083] method 19F-NMR spectroscopy: A Varian Mercury 200 MHz spectrometer acting on fluorine nuclei was used to obtain the structures, number average molecular weights and compositions of the PFPE oils reported in the Examples below. 19 F-NMR spectra were obtained on pure samples using CFCl3 as an internal standard. Hexafluorobenzene was also used as the solvent.

[0084] Determination of Peroxide Content (PO): Peroxide content (PO) is expressed as grams of peroxide oxygen per 100 g of polymer. Analysis of peroxide content was performed by iodometric titration using a Mettler DL40 device equipped with a platinum electrode. The sensitivity limit for PO measurement was 0.0002%.

[0085] Complex viscosity measurement: Complex viscosity was measured in a frequency sweep test according to ISO 6721 part 10 using an MCR502 Anton-Paar rheometer in parallel plate geometry (25 mm diameter).

[0086] Gel Permeation Chromatography (GPC): The analysis was performed on a mixed CCD column with a Waters 410 refractometer detector using HFE7100 as the eluent.

[0087] Example 1 - Synthesis of copolymer (P-1) The reaction was carried out in a 1000 mL cylindrical photochemical glass reactor equipped with a high pressure mercury lamp (HANAU TQ150), a magnetic stirrer, a thermocouple and a condenser housed in a quartz cylinder.

[0088] 200.3 g of starting peroxide perfluoropolyether oil was charged into a photochemical reactor along with 1501 g of Galden® HT200 and 1.30 g of PBVE and thoroughly stirred to obtain a homogeneous mixture. The reaction mixture was then cooled to about 10° C. in an ice / water bath and nitrogen was purged into the system at a rate of 1.0 Nl / h. The UV lamp was switched on.

[0089] After 55 hours of irradiation, the lamp was switched off and the reaction mixture was transferred to a second glass reactor and fluorinated at 40° C. with 1.0 Nl / h of fluorine gas in the presence of UV radiation for a total of 24 hours. 19 F-NMR analysis confirmed the complete fluorination of the product and the absence of -CF2COF and -COF termini at the chain ends.

[0090] The resulting solution was distilled at 240° C. for 4 h in a round-bottom flask equipped with a magnetic stirrer to remove the solvent.

[0091] Distillation was carried out first at atmospheric pressure and then under reduced pressure (0.1 mbar) until complete removal of the solvent.

[0092] 163.6 g of copolymer (P-1) in a clear, viscous form was obtained as residue, which was analyzed by iodometric titration to confirm complete removal of the peroxide units.

[0093] 19 F-NMR analysis confirmed the absence of residual peroxide. The polymer (P-1) had m / n=1.0 and T, T'=-CF3.

[0094] Example 2 - Comparative polymer without PBVE (C-1 ∧ Synthesis of The same photochemical apparatus and peroxide perfluoropolyether precursor as in Example 1 were employed for this comparative example.

[0095] 199.9 g of the starting peroxide perfluoropolyether oil was charged to a photochemical reactor along with 1502 g of Galden® HT200 and thoroughly mixed to obtain a homogenous mixture.

[0096] The synthesis then proceeded as described in Example 1. 19 F-NMR analysis confirmed the complete fluorination of the product and the absence of -CF2COF and -COF termini at the chain ends.

[0097] Distillation was also carried out as described in Example 1.

[0098] 172.4g of comparative polymer (C-1 ∧ ) was obtained in the form of a clear viscous oil as a residue which was analyzed by iodometric titration to confirm the complete removal of the peroxide units.

[0099] 19 F-NMR analysis confirmed the absence of residual peroxide. ∧ ) had m / n=1.0 and T, T'=-CF3.

[0100] [Table 1]

[0101] The increase in molecular weight distribution and complex viscosity of the copolymer (P-1) according to the present invention is greater than that of the comparative polymer (C-1 ∧ ) was confirmed to have undergone chain extension.

Claims

1. A block copolymer [copolymer (P)] having two chain ends (wherein both said chain ends contain a perfluorinated alkyl group), and first and second (per)fluoropolyether chains [PFPE chains], each having two chain ends (wherein the first chain ends of said first and second PFPE chains contain a perfluorinated alkyl group, and the second chain ends of said first and second PFPE chains are of formula (I): (I) -[A - B]- and are linked to each other via the block of), wherein, (A) is a PFPE chain, (B) is a moiety according to the following formula (II): 【Chemical 1】 and, wherein, n is an integer from 1 to 3; R １ ~R ４ each independently represents a fluorine atom, a linear or branched perfluorinated alkyl group having 1 to 6 carbon atoms, or the formula (III): (III)-(R １０ ) ｔ [C(R １１ )(R １２ )-C(R １３ )(R １４ )(R １５ )] ｚ selected from, preferably consisting of, the group consisting of wherein, R １０ is an oxygen atom or a divalent / trivalent / tetravalent perfluorinated alkyl chain containing 1 to 24 carbon atoms, optionally interrupted by and / or containing at least one oxygen atom, t is zero or 1, z is an integer from 1 to 3, R １１ ~R １５ each independently represents a fluorine atom, a linear or branched perfluorinated alkyl group having 1 to 6 carbon atoms, and the formula (IV): -[(A ∧ ) ａ -(B ∧ ) ｖ )-(C ∧ )-T (IV) and is selected from, preferably consisting of, the group of groups containing wherein, A ∧ is a PFPE chain, a is zero or 1, v is zero or an integer from 1 to 3, B ∧ is a group of the formula -[C(R １∧ )(R ２∧ )-C(R ３∧ )(R ４∧ )- and Here, R １∧ to R ４∧ each independently has the meaning defined above with respect to R １ to R ４ and C ∧ is a PFPE chain, T is a perfluorinated alkyl group, wherein, ‥ the A and B in formula (I) and the A in formula (IV) ∧ and B ∧ are statistically distributed, ‥ R １ ~R ４ at least one of which is a group of formula (III), ‥ R １１ or R １２ one of and R １３ ~R １５ one of is a group of formula (IV), where a is 1, ‥ (B + B ∧ ) the total is from 1 to 15 block copolymer [copolymer (P)].

2. - The first and second PFPE chains as defined in claim 1, the A, A ∧ , C ∧ are the same as or different from each other; and / or - Each of said perfluorinated alkyl groups, which are the same as or different from each other, is a linear perfluoroalkyl group containing 1 to 3 carbon atoms; and / or - The first PFPE chain is bonded to at least one of the blocks of formula (I) via a sigma bond or a group selected from -CF ２ -, -CF ２ CF ２ - or -O-; and / or - The second PFPE chain is bonded to at least one of the blocks of formula (I) via a sigma bond or a group selected from -CF ２ -, -CF ２ CF ２ - or -O-; - In formula (I), the said A and B are connected via a group selected from sigma bond or -CF ２ - or -CF ２ CF ２ - and are connected through a group selected therefrom, The copolymer (P) according to claim 1.

3. Said first and second PFPE chains, A in formula (I), and said A in formula (IV) ∧ and C ∧ each of which is independently (Rf-i)-CFXO- (wherein X is F or CF ３ is); (Rf-ii)-CFXCFXO- (wherein, each occurrence being equal or different, X is F or CF ３ provided that at least one of X is -F); (Rf-iii)-CF ２ CF ２ CW ２ O-(wherein each of W, which are the same as or different from each other, is F, Cl, H); (Rf-iv)-CF ２ CF ２ CF ２ CF ２ O-; (Rf-v) - (CF ２ ) ｊ -CFZ-O- (where j is an integer from 0 to 3, and Z is a group of the general formula -O-R （ｆ－ａ） -T, where R （ｆ－ａ） is a fluoropolyoxyalkene chain containing 0 to 10 repeating units of a number, and the repeating unit is as follows: each of X is independently F or CF ３ is, -CFXO-, -CF ２ CFXO-, -CF ２ CF ２ CF ２ O-, -CF ２ CF ２ CF ２ CF ２ O- is selected from, and T is a C １ to C ３ perfluoroalkyl group) A repeating unit independently selected from the group consisting of, preferably a partial or complete fluorinated chain [chain (R ｆ ))], the copolymer (P) according to claim 1.

4. In formula (II): - n is an integer equal to 1 or 2; and / or - At least one of the substituents R1 to R4 is a group of formula (III) as defined in claim 1, and the other substituents are each independently selected from a fluorine atom, or a perfluorinated alkyl chain having 1 to 3 carbon atoms, more preferably a fluorine atom, or a perfluorinated alkyl chain having 1 carbon atom, The copolymer (P) according to claim 1.

5. In formula (III): - t is 0; or - t is 1 and R １０ is the following formula: (R １０ - i) - (CF ２ ) ｄ (O) ｅ (CF ２ O) ｆ R ＣＦ (O) ｅ＊ (CF ２ ) ｄ＊ (CF2O) ｆ＊ (wherein, each of d, d*, e, e*, f and f* is independently zero or 1, R ＣＦ is a perfluoroalkyl chain containing 1 to 12, preferably 1 to 8 carbon atoms, optionally interrupted by one or more oxygen atoms); (R １０ - ii) - O - (C ３ F ６ O) ｈ - (CF ２ ) ｉ - (C ３ F ６ O) ｊ - O - (wherein h = j, h + j is from 2 to 6, and i is from 2 to 6)) and follows one of, The copolymer (P) according to claim 1.

6. In formula (III): - z is equal to 1, and R １０ is an oxygen atom, or a divalent perfluorinated alkyl chain containing 1 to 24 carbon atoms, optionally interrupted by and / or containing at least one oxygen atom; and / or - Substituent R １１ and R １２ One of them is a group of formula (IV) as defined in claim 1, and the other substituents are selected from a fluorine atom or a perfluorinated alkyl chain having 1 to 3 carbon atoms; and / or - Substituent R １３ ~R １５ One of them is a group of formula (IV), and the other two substituents are independently selected from a fluorine atom or a perfluorinated alkyl chain having 1 to 3 carbon atoms. The copolymer (P) according to claim 1.

7. In formula (IV): - a is 1, v is 1, B ∧ is a group of formula -[C(R １∧ )(R ２∧ )-C(R ３∧ )(R ４∧ )- (wherein R １∧ to R ４∧ are each independently selected from a fluorine atom, a linear or branched perfluorinated alkyl group having 1 to 6 carbon atoms, preferably a group consisting of these), or a group of formula (III) as defined in claim 1 The copolymer (P) according to claim 1.

8. The copolymer (P) according to claim 1, wherein the copolymer (P) has a complex viscosity measured at 0.1 rad / s and 25 °C according to ISO 6721 part 10 of 10 Pa*s to 2000 Pa*s.

9. The copolymer (P) according to claim 1, which does not contain pendant groups containing moieties capable of undergoing chemical reactions.

10. A mixture [mixture (P)] containing two or more copolymers (P) as defined in claim 1.

11. A process [process (P)] for the production of a copolymer (P) as defined in claim 1 or a mixture (P) as defined in claim 10, said process comprising: a) comprising a (per)fluoropolyether chain having two chain ends, each of said chain ends having a perfluorinated alkyl chain having 1 to 3 carbon atoms and optionally containing one or more functional end groups selected from chlorine atoms or acyl fluorides, fluoroformates and ketones, said chain ends being bonded to opposite sides of said (per)fluoropolyether chain, said (per)fluoropolyether chain comprising repeating units independently selected from the group consisting of formulas (Rf-i) to (Rf-v) as defined in claim 3, preferably consisting of them, and having a peroxide content (PO) of 0.1 to 4, defined as grams of active oxygen (Mw = 16) in 100 g of PFPE peroxide, at least one peroxide (per)fluoropolyether polymer [PFPE peroxide], Formula (III-p): [Chemical Formula 2] (wherein, R ２１ to R ２３ and R ３１ to R ３３ Each of them is independently a fluorine atom or a linear or branched perfluorinated alkyl group having 1 to 6 carbon atoms, R １０ is a linear or branched perfluorinated alkyl group containing an oxygen atom, 1 to 24 carbon atoms, optionally interrupted by and / or containing at least one oxygen atom, t is zero or 1, preferably 1; each of z* and z** is independently 1 or 2) contacting with at least one perfluorinated compound of: where the amount of said compound of formula (III-p) is less than 5% by weight of the amount of said PFPE peroxide; b) reacting said PFPE peroxide with said compound of formula (III) in the presence of UV radiation or heating; c) fluorinating to obtain said copolymer (P) A process comprising.

12. t is 1 and the two, three or four unsaturated moieties are bonded to the same or different carbon atoms belonging to R １０ Process (P) according to claim 11, wherein the two, three or four unsaturated moieties are bonded to the same or different carbon atoms belonging to R

13. Said at least one compound of formula (III-p) has the following formula: CF ２ =CF(R １０ ) ｔ CF = CF ２ in accordance with where t is zero or 1, R １０ is the following formula: (R １０ - i) - (CF ２ ) ｄ (O) ｅ (CF ２ O) ｆ R ＣＦ (O) ｅ＊ (CF ２ ) ｄ＊ (CF2O) ｆ＊ (wherein, each of d, d*, e, e*, f and f* is independently zero or 1, R ＣＦ is a perfluoroalkyl chain containing 1 to 12, preferably 1 to 8 carbon atoms, optionally interrupted by one or more oxygen atoms); (R １０ - ii) - O - (C ３ F ６ O) ｈ - (CF ２ ) ｉ - (C ３ F ６ O) ｊ - O - (where h = j, h + j is 2 to 6, and i is 2 to 6)) according to one of: The process (P) according to claim 12.

14. Said process (P) comprises - Before step (a), a step of partial reduction of peroxide bonds in the PFPE peroxide, preferably by chemical reduction, UV treatment, or heat treatment; and / or - After step (c), a step (d) of removing the solvent and / or a step (e) of fractionation The process (P) according to claim 11, comprising.

15. A composition [composition (CL)] comprising a copolymer (P) as defined in claim 1 or a mixture (P) as defined in claim 10, at least one base oil selected from the group consisting of partially fluorinated, fully fluorinated, and hydrogenated base oils (provided that the base oil is capable of forming a solution with the copolymer (P)), and optionally at least one additive selected from thickeners, rust inhibitors, antioxidants, heat stabilizers, pour point depressants, antiwear agents such as those for high pressure, dispersants, tracers, dyes, talc, and inorganic fillers.

16. A method of lubricating at least one surface of at least one article, the method comprising contacting the copolymer (P) as defined in claim 1 or the mixture (P) as defined in claim 10 with the at least one surface.

17. The method according to claim 16, wherein the article is selected from pumps for oil and gas applications such as submersible electric pumps and the like, rotating machinery such as steam turbines and gas turbines, electrical connectors, bearings of fan clutches or cooling fans, or heavy-duty truck automatic clutches, more particularly the bearings of said clutches.

18. A method of canceling vibrations and / or shocks in a device, the method comprising providing a device including a damping device, the damping device including at least one copolymer (P) as defined in claim 1 or the mixture (P) as defined in claim 10.

19. A method of lubricating at least one surface of at least one article, the method comprising contacting the composition (CL) as defined in claim 15 with the at least one surface.

20. A method of canceling vibrations and / or shocks in a device, the method comprising providing a device including a damping device, the damping device including the composition (CL) as defined in claim 15.

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