(Per)fluoropolyether polymer

Abstract

The present invention relates to a new process for the synthesis of (per)fluoropolyether polymers, to certain new (per)fluoropolyether polymers. The present invention also relates to the use of the (per)fluoropolyether polymers thus obtained as intermediate compounds for the manufacture of further polymers, which are suitable for use as lubricants notably for magnetic recording media (MRM).

Description

[0001] Cross-referencing of related patent applications

[0002] This application claims priority to European Patent Application No. 16204181.8, filed on December 14, 2016, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] This invention relates to a novel process for synthesizing (per)fluoropolyether polymers, and to certain novel (per)fluoropolyether polymers. The invention also relates to the use of the (per)fluoropolyether polymers thus obtained as intermediate compounds for the manufacture of other polymers suitable for use as lubricants, notably for magnetic recording media (MRMs). Background Technology

[0004] Among fluorinated polymers, perfluoropolyether polymers (PFPEs) are well-known and have attracted considerable attention due to their chemical and physical properties, making them particularly attractive as lubricants.

[0005] The synthesis of several PFPE polymers has been disclosed in this field. The first synthesis of an unspecified mixture of perfluorinated polyethers was reported in 1953, yielding an oily product during the photoligomerization of hexafluoropropylene. Since then, many different perfluorinated polyethers have been synthesized and described in the literature. (ALLEN, Geoffrey et al., COMPREHENSIVE POLYMER SCIENCE-Second supplement. Edited by SIR ALLEN, Geoffrey et al., Elsevier Science & Technology Books, 1996. ISBN 0080427081. pp. 347-388).

[0006] For example, the catalytic polymerization of perfluorinated epoxides (such as notably hexafluoropropylene oxide (HFPO)) produced under the trade name was first disclosed by researchers at DuPont. Commercially available products containing the formula -[CF(CF3)CF2O] y - The main chain of repeating units. Then, Montetedison researchers disclosed the photochemical oxidation of perfluoroolefins (such as tetrafluoroethylene and hexafluoropropylene), which produced products under the trade name Commercially available products having a random distribution of the formula -[(CF2O)] m (CF2CF(R)O)n The main chain of repeating units, where R is -F or -CF3. A ring-opening polymerization of partially fluorinated oxetanes, followed by fluorination, was disclosed by Daikin Company and produced under the trade name... Commercially available products that contain the formula -(CF2CF2CF2O) p - The main chain of repeating units.

[0007] The main difference between (all)fluoropolyether polymers known in this art lies in the following facts: polymers and Polymers are homopolymers characterized by an ordered structure, containing only one type of repeating unit, namely, -[CF(CF3)CF2O]. y - and -(CF2CF2CF2O) p -. Differently, A polymer is a copolymer characterized by the presence of two or more repeating units of different formulas, randomly (or statistically) distributed along the main chain. This random (or statistical) distribution of repeating units is due to a manufacturing process based on photochemical oxidation. However, the random distribution of repeating units can produce a main chain containing multiple consecutive repeating units with one carbon atom (i.e., having the formula -CF₂O-), which on the one hand increases the flexibility of the polymer main chain, but on the other hand constitutes a weakness in the polymer main chain because they are more susceptible to attack by metals and / or Lewis acids.

[0008] The polymerization of fluorinated vinyl ether alcohols, followed by the fluorination of the intermediate partially fluorinated structure, is disclosed by FEIRING, Andrew E. Synthesis of New Fluoropolymers: Tailoring Macromolecular Properties with Fluorinated Substituents. Journal of Macromolecular Science. 1994, Vol. A31, No. 11, pp. 1657-1673. However, the first approach described in this article begins with a partially fluorinated compound containing both a hydroxyl group and a vinyl ether group within the same molecule (i.e., CF2=CFOCF2CF(CF3)OCF2CF2CH2OH), such that the final polymer contains only one compound with the formula -(CF2CF2OCF2CF(CF3)OCF2CF2CF2O). n- The main chain of repeating units. Another approach described in this article involves the reaction of the compounds mentioned above having the formula CF2=CFOCF2CF(CF3)OCF2CF2CH2OH with partially fluorinated diols (e.g., having the formula HOCH2(CF2)3CH2OH) to provide telechelic diols to be used in the production of additional copolymers, such as those described in US 5185421 (EIDU PONT DE NEMOURS AND COMPANY) and by YANG, S. et al. Novel fluorine-containing anionic aqueous polyurethane. Journal of Macromolecular Science. 1993, Vol. 30, pp. 241-252.

[0009] Fluorinated polyether compounds have also been disclosed in US 2016 / 0137947 (ASAHI GLASS COMPANY, LIMITED). This patent application specifically discloses fluorinated polyether compounds represented by the following formula:

[0010] {XO-[(CF2CF2O) a -(CF2CF2CF2CF2O) b ]} m -Y-{[(OCF2CF2) c -(OCF2CF2CF2CF2) d ]-OZ} n

[0011] in

[0012] m ranges from 1 to 10;

[0013] n is from 0 to 10;

[0014] X is a group having a hydroxyl, carboxyl, ester, or aryl group;

[0015] Y is an alkane group with a (m+n) valence, an alkane group with a (m+n) valence having an ether oxygen atom inserted between carbon atoms, a fluoroalkane group with a (m+n) valence, a fluoroalkane group with an ether oxygen atom inserted between carbon atoms, or a cyclotriphosphazene structure (P3N3); and

[0016] Z is a group that does not have a hydroxyl, carboxyl, ester, or aryl group and has a haloalkyl group (provided the halogen atom is a fluorine or chlorine atom), or a haloalkyl group with an ether oxygen inserted between carbon atoms (provided the halogen atom is a fluorine or chlorine atom). In part -[(CF2CF2O)] a -(CF2CF2CF2CF2O) b In the [-] structure, the connection order of units (CF2CF2O) of number "a" and units (CF2CF2CF2CF2O) of number "b" is not restricted; that is, units (CF2CF2O) and (CF2CF2CF2CF2O) can be arranged in an unspecified, alternating manner, or at least one block consisting of multiple units (CF2CF2O) and units (CF2CF2CF2CF2O) can be connected. A structure having the following formula is preferred:

[0017] -CF2CF2O(CF2CF2CF2CF2OCF2CF2O) e -

[0018] Where e ranges from 1 to 99. Summary of the Invention

[0019] The problem faced by the applicant is to prepare (all)fluoropolyether polymers with a predefined chemical structure, namely (all)fluoropolyether polymers characterized by a non-random but a priori defined distribution of repeating units in the polymer backbone.

[0020] Surprisingly, the applicant has discovered a process that can be conveniently applied on an industrial scale to synthesize perfluoropolyether polymers in which repeating units are not randomly distributed in the main chain.

[0021] In a first aspect, the present invention relates to a process for synthesizing at least one polymer [polymer (FH)] comprising a partially fluorinated polyether backbone having two chain ends [process (P]]. FH )], wherein the chain end comprises at least one group selected from hydroxy, allyl, and vinyl groups, and the process includes the following steps:

[0022] (I) Contacting at least one perfluorinated compound [compound (F)] containing at least two unsaturated groups selected from vinyl and allyl groups with at least one fully or partially hydrogenated compound [compound (H)] containing at least two hydroxyl groups.

[0023] To provide polymers (FH),

[0024] The polymer (FH) is characterized in that its main chain contains one or more repeating units derived from the at least one compound (F), which are arranged alternately with one or more repeating units derived from the at least one compound (H).

[0025] Advantageously, the process according to the invention allows for the preparation of polymers comprising a (per)fluoropolyether backbone containing repeating units distributed in a predetermined and well-defined manner within the backbone.

[0026] The applicant notes that, as in the process according to the invention (P) FH The polymer (FH) obtained after step (I) is new.

[0027] Therefore, in a second aspect, the present invention relates to a polymer [polymer (FH*)] comprising a partially fluorinated polyether backbone having two ends, wherein each of the ends comprises a group selected from hydroxyl, allyl, or vinyl groups; and

[0028] The main chain conforms to the following structure (R) FH -I):

[0029] -[CF2CFH(CF2) z OR CF O(CF2) z* CFHCF2-OR H O] y - (R FH -I)

[0030] in

[0031] Each of z and z* is independently 0 or 1;

[0032] R CF It is a perfluoroalkylene chain containing 1 to 20, preferably 2 to 10, carbon atoms and optionally interrupted by one or more oxygen atoms;

[0033] R H It is a straight-chain or branched alkylene chain containing 2 to 12, preferably 2 to 6 carbon atoms, said alkyl chain optionally containing one or more fluorine atoms and optionally interrupted by one or more oxygen atoms; and

[0034] y is an integer such that the number-average molecular weight of the main chain of the polymer (FH) is from 306 to 50,000, preferably from 400 to 10,000, more preferably from 500 to 5,000, and even more preferably from 600 to 3,000.

[0035] Advantageously, the at least one polymer (FH) can be further reacted to provide a polymer comprising a fully fluorinated polyether backbone.

[0036] Therefore, in a third aspect, the present invention relates to a process for synthesizing a polymer [polymer (PFPE)] comprising a perfluorinated polyether backbone having two chain ends. PFPE The process includes the following steps: [The process comprises at least one group selected from -OC (=O)F and a perfluorinated alkyl chain comprising 2 to 3 carbon atoms.]

[0037] (III) Making at least one process as defined above (P) FH The polymer (FH) obtained in step (I) is contacted with a fluorine source to provide polymer (PFPE).

[0038] In a fourth aspect, the present invention relates to a perfluoropolyether polymer [polymer (PFPE)], said polymer (PFPE) comprising a perfluoropolyether backbone having two chain ends, wherein:

[0039] Each chain end contains at least one group selected from -OC (=O)F and a perfluorinated alkyl chain containing 2 to 3 carbon atoms, and the main chain conforms to the following structure (R pf -I):

[0040] -[CF2CF2(CF2) z OR CF O-(CF2) z* CF2CF2-OR F O] y - (R pf -I)

[0041] in

[0042] R CF It is a perfluoroalkyl chain containing 1 to 20, preferably 2 to 10 carbon atoms, optionally interrupted by one or more oxygen atoms;

[0043] R F It is a perfluoroalkyl chain containing 2 to 12, preferably 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms;

[0044] Each of z and z* is independently 0 or 1; and

[0045] y is an integer such that the number-average molecular weight of the main chain of the polymer (PFPE) is from 414 to 70,000, preferably from 600 to 50,000, more preferably from 700 to 10,000, and even more preferably from 800 to 5,000.

[0046] The premise is:

[0047] - When both z and z* are 0, the portion R CFand the aforementioned part R F At least one of them is different from -CF2CF2- and -CF2CF2CF2CF2-;

[0048] - When both z and z* are 1, part of R CF and part of R F At least one of them is different from -CF2CF2CF2-.

[0049] The applicant has unexpectedly discovered that the process according to the invention allows for the adjustment of the structure of these perfluoropolyether polymers, and thus their physical and chemical properties, and notably the adjustment of the stiffness (or mobility) of the polymer backbone.

[0050] In another aspect, the present invention relates to the use of at least one polymer (FH) as defined above as an intermediate compound in the synthesis of at least one polymer (PFPE) as defined above. Detailed Implementation

[0051] For the purposes of this specification and the following claims:

[0052] - The use of parentheses around identifying symbols or numbers, such as in expressions like "polymer (PFPE)". FOR In parentheses such as )", the purpose is merely to better distinguish the symbol or number from the rest of the text, and therefore the parentheses may be omitted;

[0053] - The term "(per)fluorinated polyether" is intended to refer to one or more polyether polymers comprising a fully or partially fluorinated backbone;

[0054] - The term "perfluoropolyether" is intended to refer to one or more polyether polymers containing a fully fluorinated backbone;

[0055] - The term "neutral group" is intended to represent a fluorine atom or a straight or branched perfluoroalkyl chain having 1 to 10 carbon atoms, such as -CF3, -C2F5, C3F7;

[0056] - The term "functional group" is intended to indicate a group that is different from the neutral group. Suitable examples of the functional group are: -OH, -C(O)OR, wherein R is a hydrogen atom or a straight-chain or branched alkyl group having 1 to 6 carbon atoms; a straight-chain or branched alkyl chain having 1 to 12 carbon atoms, wherein the alkyl chain is optionally interrupted by at least one oxygen atom and / or optionally substituted by at least one -OH group; amino, amide, triazine, phosphazene, siloxane.

[0057] Preferably, the compound (F) conforms to the following formula:

[0058] CF2 = CF(CF2)z OR CF O(CF2) z* CF = CF2

[0059] in

[0060] Each of z and z* is independently 0 or 1; and

[0061] R CF It has the same meaning as the above definition for polymer PFPE.

[0062] The preferred compounds (F) are those that conform to the following formulas (FI) to (F-VIII):

[0063] (FI)CF2=CFO(CF2)2OCF=CF2

[0064] (F-II)CF2=CFO(CF2)3OCF=CF2

[0065] (F-III)CF2=CFO(CF2)4OCF=CF2

[0066] (F-IV)CF2=CFCF2O(CF2)4OCF2CF=CF2

[0067] (FV)CF2=CFO-CF2O-(CF2)2O(CF2)2O-CF2O-CF=CF2

[0068] (F-VI)CF2=CFO-CF2O-(CF2)2O-CF2O-CF=CF2

[0069] (F-VII)CF2=CFO-CF2O-(CF2)3O-CF2O-CF=CF2

[0070] (F-VIII)CF2=CFO-CF2O-(CF2)4O-CF2O-CF=CF2

[0071] Among the above compounds (F), those that conform to formulas (FV) to (F-VII) are considered new.

[0072] Therefore, in another aspect, the present invention relates to a compound of one of the formulas (FV) to (F-VII) as shown above and to the use of each of said compounds as an intermediate compound in the synthesis of a polymer (FH) or polymer (PFPE) as defined above.

[0073] Preferably, compound (H) conforms to the following formula:

[0074] HO-(R H)-OH

[0075] in

[0076] R H It is a straight or branched alkylene chain containing 2 to 12, preferably 2 to 6 carbon atoms, wherein the alkyl chain optionally contains one or more fluorine atoms and is optionally interrupted by one or more oxygen atoms.

[0077] More preferably, the alkylene chain is straight-chain.

[0078] The preferred compounds (H) are those that conform to formulas (HI) to (HV):

[0079] (HI)HOCH2(CH2)3CH2OH

[0080] (H-II)HO(CH2)2OH

[0081] (H-III)HO(CH2)3OH

[0082] (H-IV)HO(CH2)4OH

[0083] (HV)OHCH2CH2OCH2CH2OH

[0084] Preferably, the molar ratio between the compound (H) and the compound (F) is from 0.1 to 25, more preferably from 0.5 to 22, and even more preferably from 1 to 20.

[0085] According to one embodiment, step (I) optionally includes adding one or more compounds containing an unsaturated group selected from vinyl and allyl [compound (F-mono)] and / or a compound containing a hydroxyl group [compound (H-mono)] to the compound (F) and the compound (H).

[0086] The compound (F-mono) is preferably selected from those having the following formula: CF3OCF=CF2, C2F5OCF=CF2, C3F7OCF=CF2, CF3OCF2OCF=CF2, CF3CF=CF2, CF2=CF2(TFE).

[0087] The compound (H-mono) is preferably selected from those having the following formula: CH3OH, C2H5OH, C3H7OH, CF3CH2OH, (CF3)2CHOH, and (CH3)2CHOH.

[0088] Preferably, step (I) is performed under heating, for example at a temperature ranging from 30°C to 80°C, preferably from 35°C to 75°C.

[0089] Preferably, step (I) is carried out in the presence of a base. A suitable base is selected from the group consisting of NaOH, KOH, NH4OH, NaH, trialkylamine, guanidine (such as notably tetramethylguanidine), and 1,4-diazabicyclo[2.2.2]octane (“DABCO”).

[0090] Optionally, step (I) is carried out in the presence of a solvent, preferably selected from the group consisting of at least one polar aprotic solvent or at least one hydrofluoroether (HFE).

[0091] Preferably, the polar aprotic solvent is selected from the group consisting of, and more preferably, the following: compounds with two hydroxyl groups, dimethoxyethane (glycol dimethyl ether), bis(2-methoxyethyl) ether (diethylene glycol dimethyl ether), triethylene glycol dimethyl ether (triethylene glycol dimethyl ether), tetraethylene glycol dimethyl ether (tetraethylene glycol dimethyl ether), tetrahydrofuran, acetonitrile, dimethyl sulfoxide, dimethylformamide, and ethylene polyoxide dimethyl ether. Acetonitrile is particularly preferred.

[0092] Step (I) is preferably performed by adding compound (F) to compound (H). Alternatively, compound (H) can be added to compound (F), or both compound (F) and compound (H) can be added to the reaction environment simultaneously.

[0093] Preferably, (R) CF A fluoroalkyl chain is a straight or branched chain containing 2 to 10, more preferably 2 to 6 carbon atoms and optionally interrupted by one or more oxygen atoms.

[0094] The part (R) CF A suitable example of a binary chain is the following:

[0095] -CF2-;-C2F4-;-C3F6-;-C4F8-;-C x F 2x -;

[0096] -CF2O-CF2CF2O-CF2CF2O-CF2-;

[0097] -CF2O-(CF2)2OCF2-;

[0098] -CF2O-(CF2)3OCF2-;

[0099] -CF2O-(CF2)4OCF2-;

[0100] Where x is an integer from 5 to 12, more preferably from 5 to 8.

[0101] According to a preferred embodiment, (RCF) does not contain two consecutive molecules of the formula -(CF2O). a - repeating units.

[0102] Depending on the molar ratio of compound (F) to compound (H) used in step (I), one or more polymers (FH) containing two allyl or vinyl groups, two hydroxyl groups, or one hydroxyl group and one allyl or vinyl group at their chain ends are obtained.

[0103] More specifically, when the molar ratio between compound (F) and compound (H) is greater than 1, i.e. when compound (F) is used in excess of compound (H) in molar ratio, it is preferable to obtain a polymer (FH) containing two allyl or vinyl groups at its chain ends.

[0104] According to this first variant, the following general formula (FH) is obtained. b1 Polymers (FH):

[0105] CF2 = CF(CF2) z OR CF O(CF2) z* CFHCF2-OR H O-[CF2CFH(CF2) z OR CF O(CF2) z* CFHCF2-OR H O] y -CF2CFH(CF2) z OR CF O(CF2) z* CF = CF2 (FH b1 )

[0106] Where R CF R H z, z*, and y are as defined above.

[0107] Those skilled in the art will understand that having the general formula (FH) b1 Very identical polymers can be written using different general formulas—however, even if the polymers are intended to be very identical. One alternative is, for example, the following:

[0108] CF2 = CF(CF2) z O[R CF O(CF2) z* CFHCF2-OR H O-CF2CFH(CF2)zO] y R CF O(CF2) z*CF = CF2(FH b1* )

[0109] Where R CF R H z, z*, and y are as defined above.

[0110] Preferably, when the molar ratio between compound (F) and compound (H) is less than 1, i.e. when compound (H) is used in excess of compound (F) in molar ratio, a polymer (FH) containing two hydroxyl groups at its chain ends is preferably obtained.

[0111] According to this second variant, the following general formula (FH) is obtained. b2 Polymers (FH):

[0112] HO-R H -O[CF2CFH(CF2) z OR CF O(CF2) z* CFHCF2-OR H O] y -H (FH b2 )

[0113] Where R CF R H z, z*, and y are as defined above.

[0114] Furthermore, when the molar ratio between compound (F) and compound (H) is about 1, that is, when stoichiometric amounts of compound (F) and compound (H) are used, a polymer (FH) containing a hydroxyl group at one end of the chain and an allyl or vinyl group at the other end of the chain is preferably obtained.

[0115] According to this third variant, the following general formula (FH) is obtained. b3 Polymers (FH):

[0116] CF2 = CF(CF2) z OR CF O(CF2) z* CFHCF2-OR H O-[CF2CFH(CF2) z OR CF O(CF2) z* CFHCF2-OR H O] y -H (FH b3 )

[0117] Where R CF R H z, z*, and y are as defined above.

[0118] Those skilled in the art will understand that, by controlling the reaction conditions of step (I), a polymer (FH) as defined above can be obtained. b1 ), polymer (FH b2 ) and polymers (FH b3 The mixture is included within the scope of this invention. As a result, after step (III), a mixture of polymers (PFPE) is obtained, as will be described in more detail later.

[0119] At least one conforming to the formula (FH) defined above b1 ) to (FH b3 The polymer (FH) of any one of the following is advantageous in the process (P) PFPE The reaction occurs in step (III) of the reaction.

[0120] Advantageously, step (III) is carried out in the presence of a fluorine source.

[0121] Preferably, the fluorine source is a gas containing fluorine atoms. More preferably, the fluorine source is fluorine gas (F2).

[0122] Advantageously, the fluorine source in step (III) is used in combination with a dilution gas, which is preferably selected from inert gases such as helium and nitrogen.

[0123] Advantageously, a halogenated olefin can be added to generate fluorine radicals to aid the fluorination step. The halogenated olefin may be selected from, for example, tetrafluoroethylene (TFE), hexafluoropropylene (HFP), octafluorobutene, perfluoropentene, perfluorohexene, perfluoroheptene, perfluorooctene, perfluorocyclobutene, perfluorocyclopentene, perfluorocyclohexene, trichlorofluoroethylene (CTFE), dichlorodifluoroethylene, pentachlorofluoropropylene, perfluorobutadiene, perfluoro-methyl vinyl ether, perfluoro-ethyl vinyl ether, perfluoro-propyl vinyl ether; CF3OClC=CClF, trichloroethylene, tetrachloroethylene, dichloroethylene isomers; and fluoro-m-dioxanecyclopentene.

[0124] According to the process (P) PFPE The first variant of ) makes it conform to the formula (FH) defined above. b1 The polymer (FH) in the process (P) PFPE The reaction occurs in step (III) to provide a polymer (P) containing the components described above. PFPE Polymers defined as having a perfluoropolyether backbone with two chain ends [polymer (PFPE)] b1 [ ], wherein two of the chain ends contain perfluorinated alkyl chains containing 2 or 3 carbon atoms.

[0125] According to the process (P) PFPEThe second variant of ) when at least one conforms to the formula (FH) defined above. b2 ) and / or formula (FH b3 The polymer (FH) in the process (P) PFPE During the reaction in step (III), steps (II) and (IV) are advantageously performed before and after step (III), respectively.

[0126] Preferably, by making the at least one conform to the formula (FH) defined above. b2 ) and / or formula (FH b3 Step (II) is performed by contacting the polymer (FH) with at least one compound capable of forming fluoroformate groups.

[0127] More preferably, step (II) is performed by contacting the polymer (FH) with F2C (=O), ClFC (=O), or BrFC (=O).

[0128] Following step (II), the following polymer was obtained:

[0129] (FH b2-COF )F(O=)COR H -O[CF2CFH(CF2) z OR CF O(CF2) z* CFHCF2-OR H O] y -C(=O)F

[0130] (FH b3-COF )CF2=CF(CF2) z ORC F O(CF2) z* CFHCF2-OR H O-[CF2CFH(CF2) z OR CF O(CF2) z* CFHCF2-OR H O] y -C(=O)F

[0131] Where R H R CF z, z*, and y are as defined above.

[0132] Then the polymer (FH) is made b2-COF ) and / or the polymer (FH b3-COF The reaction occurs in step (III) of the process according to the invention.

[0133] Preferably, step (III) is carried out under the same conditions and using the same reactants as defined above.

[0134] Following step (III), the following polymers containing a perfluorinated backbone were obtained:

[0135] (PFPE b2-COF )F(O=)COR F -O[CF2CF2(CF2) z OR CF O(CF2) z* CF2CF2-OR F O] y -C(=O)F

[0136] (PFPE b3-COF )CF3CF2(CF2) z OR CF O(CF2) z* CF2CF2-OR F O-[CF2CF2(CF2) z OR CF O(CF2) z* CF2CF2-OR F O] y -C(=O)F

[0137] Where R F R CF z, z*, and y are as defined above.

[0138] Then the polymer (PFPE) is made b2-COF ) and / or the polymer (PFPE) b3-COF The reaction occurs in step (IV) of the process according to the invention.

[0139] Step (IV) involves reacting each fluoroformate group to provide a polymer comprising a perfluoropolyether backbone having two chain ends [polymer (PFPE)]. EST ], wherein at least one end of the chain contains at least one having the formula -C(=O)OR alk The group, wherein R alk It is a straight-chain or branched alkyl chain containing 1 to 10 carbon atoms.

[0140] Preferably, the polymer obtained in step (III) is reacted with at least one polymer having the formula R alk The compound with -OH is contacted to perform step (IV), where R alk It is a straight-chain or branched alkyl chain containing 1 to 10 carbon atoms.

[0141] Therefore, in a preferred aspect, the present invention relates to a method for synthesizing at least one polymer (PFPE). EST The process includes steps (II), (III), and (IV) as defined above [process (P)]. PFPE-EST )).

[0142] In a fifth aspect, the present invention relates to a perfluoropolyether polymer [polymer (PFPE)] EST The polymer (PFPE) EST It contains a perfluoropolyether backbone with two ends.

[0143] At least one of the chain ends contains at least one group -C(=O)OR alk , where R alk It is a straight-chain or branched alkyl chain containing 1 to 10 carbon atoms; and

[0144] The main chain therein conforms to the structure (R) defined above for the polymer (PFPE). pf -I).

[0145] Preferably, the polymer (PFPE) EST The main chain of ) is different from that of -[(C2F4O) a (C4F8O) b ] y -,

[0146] Each of a, b, and y is an integer greater than 1.

[0147] Following step (IV), the following polymers were obtained:

[0148] (PFPE EST-b2 )

[0149] R alk O(O=)CR F -[OCF2CF2(CF2) z OR CF O(CF2) z* CF2CF2-OR F ] y -C(=O)OR alk

[0150] (PFPE EST-b3 )

[0151] CF3CF2(CF2) z OR CF O(CF2) z* CF2CF2-OR F -[OCF2CF2(CF2) zOR CF O(CF2) z* CF2CF2-OR F ] y -C(=O)OR alk

[0152] Where R F R CF R alk z, z*, and y are as defined above.

[0153] The polymer (PFPE) EST It can be used as an intermediate for the synthesis of other derivatives.

[0154] Advantageously, the polymer (PFPE) EST More preferably, the polymer (PFPE) EST-b2 ) and the polymer (PFPE) EST-b3 Each of the following is contacted with at least one reducing agent to provide a perfluoropolyether polymer comprising a perfluoropolyether backbone having two ends as defined above for polymer (PFPE). OH [ ], wherein at least one chain end, more preferably both chain ends, contains at least one hydroxyl group, and more preferably has a group of the formula -CF2CH2OH.

[0155] Therefore, in another aspect, the present invention relates to a polymer comprising a perfluoropolyether backbone having two ends as defined above for polymer (PFPE) OH [], wherein at least one chain end contains a group having the formula -CF2CH2OH,

[0156] The premise is that the polymer (PFPE) OH The main chain of ) is different from that of -[(C2F4O) a (C4F8O) b ] y -,

[0157] Each of a, b, and y is an integer greater than 1.

[0158] More preferably, the polymer (PFPE) OH The two ends of the chain contain groups with the formula -CF2CH2OH.

[0159] Additionally, the polymer (PFPE) OH It is useful as an intermediate for synthesizing other polymers containing a perfluoropolyether backbone as defined above for polymers (PFPE).

[0160] Among other things, the applicant notes that the polymer (PFPE) OH This can be advantageously used to synthesize at least one polymer comprising a perfluoropolyether backbone with two ends as defined above for polymer (PFPE) [polymer (PFPE)]. OH-X [ ], wherein at least one end of the chain contains a component having the formula -CF2CH2O-R 1 The group, wherein R 1 It is a straight-chain or branched alkyl chain containing 1 to 16, more preferably 3 to 6 carbon atoms and substituted by at least 2, more preferably 2 to 8, or even more preferably 2 to 5 -OH groups.

[0161] Therefore, in a sixth aspect, the present invention relates to a polymer comprising a perfluoropolyether backbone having two chain ends as defined above for polymer (PFPE) [polymer (PFPE)]. OH-x [ ], wherein at least one end of the chain contains a component having the formula -CF2CH2O-R 1 The group, wherein R 1 It is a straight-chain or branched alkyl chain containing 1 to 16, more preferably 3 to 6 carbon atoms and substituted by at least 2, more preferably 2 to 8, or even more preferably 2 to 5 -OH groups.

[0162] According to a preferred embodiment, the polymer (PFPE) OH-X The two chain ends in ) contain the formula -CF2CH2O-R 1 The group, wherein R 1 It is as defined above.

[0163] According to a more preferred embodiment, at least one chain end has a group conforming to the following formula, and even more preferably, both chain ends contain a group conforming to the following formula:

[0164] -CF2CH2O-CH2CH(OH)CH2OH (PFPE OH-X1 )

[0165] -CF2CH2O-CH2CH(OH)CH2O-CH2CH(OH)CH2OH (PFPE OH-X2 )

[0166] The applicant also notes that, as defined above, polymers (PFPE) OH ) and / or polymers (PFPE) OH-X At least two of the polymers can typically be reacted together via a diepoxy coupling agent to obtain a so-called "multidentate" PFPE polymer [polymer (PFPE) OH-MD )).

[0167] Preferably, the polymer (PFPE) OH-MD It conforms to the following formula:

[0168] C e -BABC e

[0169] in:

[0170] Each C e It has the formula -CF2CH2O-R 1 The group, wherein R 1 It is a straight-chain or branched alkyl chain containing 1 to 16 carbon atoms and substituted by at least 2, more preferably 2 to 8 -OH groups, wherein each B is a formula (R) conforming to the above definition for polymers (PFPE). pf -I) group; and

[0171] A is a divalent alkyl chain containing 3 to 20 carbon atoms, said alkyl chain being substituted with at least one, preferably 1 to 10 -OH groups and optionally substituted with at least one fluorine atom.

[0172] The applicant also notes that the polymer (PFPE) OH ) and the polymer (PFPE) OH-X It can also react with at least one compound containing a cyclophosphonitrile ring, for example following the procedure disclosed in WO 2014 / 195299 (SOLVAY SPECIALTY POLYMERS ITALY SPA) to provide a compound containing at least one cyclophosphonitrile ring selected from said polymer (PFPE). OH ) and the polymer (PFPE) OH-X Polymers with substituents in the cyclophosphonitrile central core [polymer (PFPE)] OH-PN )).

[0173] The applicant notes that the PFPE polymer according to the invention, which contains at least one hydroxyl group at one or more of its chain ends, can be advantageously used as a lubricant for magnetic recording media (MRM).

[0174] Therefore, in another aspect, the present invention relates to polymers (PFPE) as defined above. OH ), polymer (PFPE) OH-X ), polymer (PFPE) OH-MD ) and / or polymers (PFPE) OH-PN Use of at least one of the following as a lubricant for magnetic recording media (MRM).

[0175] For this purpose, polymer (PFPE) OH), polymer (PFPE) OH-x ), polymer (PFPE) OH-MD ) and / or polymers (PFPE) OH-PN Advantageously, it does not contain two or more consecutive repeating motifs containing one carbon atom, i.e., repeating motifs of the formula -(CF₂O)-. Indeed, it is known that consecutive repeating motifs of the formula -(CF₂O)- make the polymer backbone more susceptible to attack by metals and Lewis acids and unable to withstand such attacks than motifs containing two or more carbon atoms. Furthermore, this weakness is particularly amplified when polymers containing two or more consecutive repeating motifs of one carbon atom are obtained, as can occur when using conventional synthesis of polymers that provide randomly distributed repeating units.

[0176] Even more importantly, PFPE polymers that do not contain two or more consecutive repeating moieties consisting of one carbon atom can withstand high temperatures. This property is particularly important in the development of lubricants for coating magnetic recording media using heat-assisted magnetic recording (HAMR) technology. HAMR is a magnetic storage technology used in hard disk drives, in which a laser is used to heat a portion of the disk being written to, causing the heat to temporarily alter the magnetic properties of the disk, reducing or eliminating the superparamagnetic effect that occurs when writing takes place. The advantage of HAMR is that it allows writing to be done on a much smaller scale than before, thus significantly increasing the amount of data that can be stored on a standard disk master.

[0177] Magnetic recording media (MRM) typically comprise multiple layers, including a non-magnetic substrate having an underlying layer sequentially deposited on each side thereon, at least one magnetic layer, and a protective overlay (preferably a carbon overlay).

[0178] In another aspect, the present invention relates to a method for lubricating a magnetic recording medium (MRM), the method comprising providing a magnetic recording medium (MRM) comprising at least one magnetic layer optionally covered by at least one carbon overlay, and dispensing a polymer (PFPE) as defined above. OH ), polymer (PFPE) OH-X ), polymer (PFPE) OH-MD ) and / or polymers (PFPE) OH-PN At least one of the following is applied to the magnetic layer or to the carbon coating layer.

[0179] The step of applying the polymer according to the invention to the MRM can be performed by any conventional method known in the art.

[0180] For example, the polymer (PFPE) as defined above can be used. OH ), polymer (PFPE) OH-X ), polymer (PFPE)OH-MD ) and / or polymers (PFPE) OH-PN At least one of the following is applied directly to the magnetic layer of the disk of the MRM, or to a protective overlay (if present).

[0181] Alternatively, the polymer (PFPE) can be first applied... OH ), polymer (PFPE) OH-X ), polymer (PFPE) OH-MD ) and / or polymers (PFPE) OH-PN At least one of the following is dissolved in a suitable solvent (such as hydrofluoroether (HFE), for example, Novec). TM HFE (from 3M) TM Commercially available), hydrofluorocarbons (HFCs), for example HFC (from DuPont) TM The disk is then immersed in the solution (S) and slowly removed from it. The solution is prepared by mixing commercially available perfluorinated hydrocarbons, chlorofluorocarbons, hydrochlorofluorocarbons, and combinations thereof to obtain a solution [S].

[0182] A conventional lifting-type long-handled spoon can be used to immerse the recording medium disk in the solution (S). Optionally, the resulting coated disk can be subjected to further treatment, such as exposure to UV radiation. Technicians can optimize the immersion duration and removal speed to achieve the desired coating thickness.

[0183] Preferably, it comprises a polymer (PFPE) as defined above. OH ), polymer (PFPE) OH-X ), polymer (PFPE) OH-MD ) and / or polymers (PFPE) OH-PN The coating of any one of the following has a thickness of from about 2 to about 30 angstroms. More preferably from 2 to The thickness.

[0184] If any patent, patent application, or disclosure incorporated herein by reference conflicts with the description of this application to the extent that it may lead to ambiguity in terminology, then this description shall take precedence.

[0185] The invention will be described in more detail below with the aid of examples included in the following experimental section; these examples are merely illustrative and are in no way intended to limit the scope of the invention.

[0186] Experimental Section

[0187] method

[0188] Number average molecular weight (Mn) is determined by NMR ( 19F-NMR and 1 Determined by H-NMR.

[0189] Example 1

[0190] Step (a): Synthesis of HO(CH2)4OCF2CFHO(CF2)4OCFHCF2O(CH2)4OH

[0191] 5.76 g of NaOH and 227.76 g of 1,4-butanediol were charged into a three-necked round-bottom flask equipped with a magnetic stirrer, temperature probe, and reflux condenser. The mixture was heated at 70 °C with stirring until the sodium hydroxide was completely dissolved. The solution was then cooled to 40 °C, and 50 g of CF2=CFO(CF2)4OCF=CF2 was added dropwise. The resulting mixture was kept at 40 °C with stirring for six hours until the perfluorodivinyl ether was completely converted. The crude product was extracted with 80 mL of water and 80 mL of CH2Cl2; the aqueous phase was extracted again with 120 mL of fresh CH2Cl2, and the two organic phases were collected and extracted with brine (80 mL). The organic phase was separated, treated with anhydrous Na2SO4, filtered, and the solvent was evaporated under reduced pressure to obtain 57.7 g of a mixture containing:

[0192] HO(CH2)4[OCF2CFHO(CF2)4OCFHCF2O(CH2)4] n OH

[0193] 78%, where n=1

[0194] 15%, where n=2

[0195] 4%, where n=3

[0196] 3%, where n = 4

[0197] Step (b): Synthesis of (EtOC(O)CF2CF2CF2OCF2CF2OCF2CF2-)2 and homologues with higher MW

[0198] 10.5 g of the alcohol mixture prepared in step (a) was dissolved in 92.4 g of 1,2,3,4-tetrachlorohexafluorobutane and loaded into a 250 ml stainless steel mechanically stirred reactor maintained at +20 °C by an external cooling bath. 2.0 Nl / h of COF2 (synthesized in a tubular reactor containing 2.0 Nl / h of F2, 3.0 Nl / h of CO, and 4.0 Nl / h of He) was fed into the reactor to convert all -OH groups to the corresponding -OC(O)F groups; the completion of the reaction was verified by online IR and GC analysis (no COF2 was converted in the reactor).

[0199] Then, 2.0 Nl / h of F2 diluted in 8.0 Nl / h of He is fed into the reactor to convert hydrogen atoms present in the formate backbone; the fluorine conversion is determined by online GC analysis: when it drops below 60%, the fluorine flow rate is increased to 2.3 Nl / h, while 0.3 Nl / h of C3F6 (diluted in 1.5 Nl / h of He) is introduced through a second inlet pipe; this fluoroolefin, activated with elemental fluorine (according to US 8742142 (SOLVAY SOLEXIS SPA)), can maintain a high fluorine conversion until complete perfluorination (indicated by a sudden drop in the fluorine conversion determined by GC to zero).

[0200] The starting material mixture was transferred to a PFA round-bottom flask containing 20 g of anhydrous ethanol, and all volatile compounds (HF, CH3CH2OC(O)F, CH3CH2OH (excess), and solvent) were evaporated under low pressure and at a temperature not exceeding 70 °C. 15.6 g of an oily, transparent, colorless liquid was obtained, and the desired structure was confirmed by analysis of IR, NMR, and GPC.

[0201] Step (c): Synthesis of HOCH2CF2(CF2)2OCF2CF2OCF2CF2CF2CF2OCF2CF2O(CF2)2CF2CH2OH

[0202] The resulting mixture from the diethyl ester polymer in step (b) is fractionated by vacuum distillation to separate the first component, which is then subjected to chemical reduction with NaBH4 to provide the corresponding diol as confirmed by NMR.

[0203] Example 2

[0204] Step (a): Synthesis of HO(CH2)3[OCF2CFHO(CF2)3OCFHCF2O(CH2)3] n OH

[0205] In a three-necked round-bottom flask equipped with a magnetic stirrer, temperature probe, and reflux condenser, 6.69 g of NaOH, 82.40 g of 1,3-propanediol, and 200 ml of acetonitrile were added. The mixture was heated at 40 °C with stirring until the sodium hydroxide was completely dissolved. Then, 107.40 g of CF2=CFO(CF2)3OCF=CF2 was added dropwise. The resulting mixture was kept at 40 °C with stirring for six hours until the perfluorodivinyl ether was completely converted. The crude product was extracted with 200 ml of water and 200 ml of CH2Cl2; the aqueous phase was extracted again with 200 ml of fresh CH2Cl2, and the two organic phases were collected and extracted with brine (200 ml). The organic phase was separated, treated with anhydrous Na2SO4, filtered, and the solvent was evaporated under reduced pressure to obtain a mixture containing:

[0206] 33% of HO(CH2)3OCF2CFHO(CF2)3OCFHCF2O(CH2)3OH, which is a byproduct of the intramolecular reaction between hydroxyl groups and vinyl groups in a product having the formula HO(CH2)3O-CF2CFHO(CF2)3OCF=CF2;

[0207] 23% HO(CH2)3[OCF2CFHO(CF2)3OCFHCF2O(CH2)3] n OH, wherein n = 2, 23% of the compound, wherein n = 3, and 21% of the compound, having as admixtures a mixture, wherein n = 4 or 5.

[0208] Step (b): Synthesis of (EtOC(O)CF2CF2OCF2CF2OCF2)2CF2 and homologues with higher MW

[0209] The same procedure described in step (b) of Example 1 was followed, but starting with 10.7 g of the mixture of alcohols obtained in step (a) of Example 2. 15.7 g of the final diethyl ester polymer was obtained.

[0210] Step (c): Synthesize polymers having the formulas HOCH2CF2CF2OCF2CF2O[(CF2CF2CF2O)(CF2CF2O)]3CF2CF2CH2OH and HOCH2CF2CF2OCF2CF2O[(CF2CF2CF2O)(CF2CF2O)]5CF2CF2CH2OH

[0211] The resulting mixture from the diethyl ester polymer in step (b) was fractionated by vacuum distillation to separate the second and third components, which were then subjected to chemical reduction with NaBH4 to provide the corresponding diols as confirmed by NMR.

[0212] Step (d): Synthesize polymers having the formula HOCH2CH(OH)CH2OCH2CF2CF2OCF2CF2O[(CF2CF2CF2O)(CF2CF2O)]3CF2CF2CH2OCH2CH(OH)CH2OH

[0213] The diol HOCH2CF2CF2OCF2CF2O[(CF2CF2CF2O)-(CF2CF2O)]3C-F2CF2--CH2OH prepared in step (c) is reacted with the methanesulfonyl derivative of acetone glycerol (Solketal) following the procedure described in US 8513471 (Solve & Solex Corporation) to provide the corresponding tetraol as confirmed by NMR analysis.

[0214] Example 3

[0215] Step (a): Synthesis of [HO(CH2)4OCF2CFHOCF2OCF2CF2]2O

[0216] In a three-necked round-bottom flask equipped with a magnetic stirrer, temperature probe, and reflux condenser, 3.95 g of NaOH, 178 g of 1,4-butanediol, and 80 ml of HCF₂CF₂OCH₂CH₂OCF₂CF₂H were added. The mixture was heated at 70 °C with stirring until the sodium hydroxide was completely dissolved, and then 54 g of [CF₂=CFOCF₂OCF₂CF₂]₂O was added dropwise. The resulting mixture was kept at 70 °C with stirring for three hours until the perfluorodivinyl ether was completely converted. The crude product was extracted with 150 ml of water; the organic layer was separated, and the solvent was evaporated at 100 °C under reduced pressure. The remaining viscous oily residue was filtered to obtain 33 g of a mixture containing: HO(CH₂)₄[OCF₂CFHOCF₂O(CF₂)₂O(CF₂)₂OCF₂OCFHCF₂O(CH₂)₄] n OH, where n ranges from 1 to 4.

[0217] Step (b): Synthesis of (EtOC(O)CF2CF2CF2OCF2CF2OCF2CF2OCF2CF2-)2O and homologues with higher MW

[0218] Follow the same procedure described in step (b) of Example 1, but start with 10.2 g of the mixture of alcohols obtained in step (a) of Example 3.

[0219] 15.0 g of the final diethyl ester polymer was obtained.

[0220] Example 4

[0221] Step (a): Synthesis of HO(CH2)4[OCF2CFHO(CF2)3OCFHCF2O(CH2)4] n OH

[0222] In a three-necked round-bottom flask equipped with a magnetic stirrer, temperature probe, and reflux condenser, 8.7 g of NaOH, 78.12 g of 1,4-butanediol, and 300 ml of acetonitrile were added. The mixture was heated at 40 °C for three hours with stirring, and then 147.91 g of CF₂=CFO(CF₂)₃OCF=CF₂ was added dropwise. The resulting mixture was maintained at 40 °C for two hours with stirring until the perfluorodivinyl ether was completely converted. The acetonitrile was then evaporated under reduced pressure at 60 °C, and the crude product was extracted with 300 ml of water and 300 ml of CH₂Cl₂. The aqueous phase was extracted again with 300 ml of fresh CH₂Cl₂, and the two organic phases were collected and extracted with brine (200 ml). The organic phase was separated, treated with anhydrous Na₂SO₄, filtered, and the solvent was evaporated under reduced pressure to obtain 167.07 g of a mixture containing:

[0223] HO(CH2)4OCF2CFHO(CF2)3OCFHCF2O(CH2)4OH, which is a byproduct of the intramolecular reaction between hydroxyl groups and vinyl groups in a product having the formula HO(CH2)4O-CF2CFHO(CF2)3OCF=CF2.

[0224] HO(CH2)4[OCF2CFHO(CF2)3OCFHCF2O(CH2)4] n OH, where n = 2 or 3, and mixtures, where n = 4 or 5.

[0225] Step (b): Synthesis of (EtOC(O)CF2CF2CF2OCF2CF2OCF2)2CF2 and homologues with higher MW

[0226] Follow the same procedure described in step (b) of Example 1, but start with 10.9 g of the mixture of alcohols obtained in step (a) of Example 4.

[0227] 16.0 g of the final diethyl ester polymer was obtained.

Claims

1. A polymer (FH) for synthesizing at least one polymer comprising a partially fluorinated polyether backbone having two ends. b2 The process of (P) is the process (P) FH The process includes the following steps: (I) Contacting at least one perfluorinated compound, i.e., compound (F), containing at least two unsaturated groups selected from vinyl and allyl, with at least one fully hydrogenated compound, i.e., compound (H), containing at least two hydroxyl groups, wherein... The compound (F) conforms to the following formula: in z and z Each of them is independently 0 or 1; and R CF It is a perfluoroalkylene chain containing 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; and The compound (H) conforms to the following formula: HO-(R H )-OH in R H It is a straight-chain or branched alkylene chain containing 2 to 12 carbon atoms, said alkyl chain optionally interrupted by one or more oxygen atoms. To provide polymers (FH b2 It conforms to the following formula: in y is an integer such that the polymer (FH) is determined by NMR analysis. b2 The number-average molecular weight of the main chain ranges from 306 to 50,000. The polymer (FH) b2 The main chain of the compound (F) is characterized by comprising one or more repeating units derived from the at least one compound (H), which are arranged alternately with one or more repeating units derived from the at least one compound (H).

2. The process according to claim 1, wherein, Step (I) includes adding one or more compounds containing an unsaturated group selected from vinyl and allyl groups, namely compound (F-mono), to the compound (F) and the compound (H), namely compound (H-mono).

3. A polymer comprising a partially fluorinated polyether backbone with two ends, namely polymer (FH). b2 It conforms to the following formula: in, z and z Each of them is either 0 or 1 independently; R CF It is a perfluoroalkylene chain containing 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; R H It is a straight-chain or branched alkylene chain containing 2 to 12 carbon atoms, said alkyl chain optionally interrupted by one or more oxygen atoms; and y is an integer such that the polymer (FH) is determined by NMR analysis. b2 The number-average molecular weight of the main chain ranges from 306 to 50,000.

4. The polymer (FH) according to claim 3 b2 ),in, R CF It is a perfluoroalkylene chain containing 2 to 10 carbon atoms and optionally interrupted by one or more oxygen atoms; R H It is a straight-chain or branched alkylene chain containing 2 to 6 carbon atoms, said alkyl chain optionally interrupted by one or more oxygen atoms; and y is an integer such that the polymer (FH) is determined by NMR analysis. b2 The number-average molecular weight of the main chain ranges from 400 to 10,000.

5. The polymer (FH) according to claim 3 b2 ),in, y is an integer such that the polymer (FH) is determined by NMR analysis. b2 The number-average molecular weight of the main chain ranges from 500 to 5,000.

6. The polymer (FH) according to claim 3 b2 ),in, y is an integer such that the polymer (FH) is determined by NMR analysis. b2 The number-average molecular weight of the main chain ranges from 600 to 3,000.

7. A process for synthesizing a polymer, or process (P), comprising a perfluorinated polyether backbone having two ends. PFPE The process includes the following steps: (The process is described in the original text, but the provided text is incomplete and cannot be accurately translated.) (III) To make at least one polymer (FH) as defined in any one of claims 1 to 6 b2 The polymer (PFPE) is contacted with a fluorine source to provide a polymer containing a perfluoropolyether backbone with two ends. in: Each chain end contains at least one group selected from -OC (=O)F and a perfluorinated alkyl chain containing 2 to 3 carbon atoms, and The main chain conforms to the following structure (R) pf -I): in R CF It is a perfluoroalkyl chain containing 1 to 20 carbon atoms, optionally interrupted by one or more oxygen atoms; R F It is a perfluoroalkyl chain containing 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; z and z Each of them is independently 0 or 1; and y is an integer such that the number-average molecular weight of the main chain of the polymer (PFPE), as determined by NMR analysis, ranges from 414 to 70,000. The premise is: - When z and z When both are 0, the portion R CF and the aforementioned part R F At least one of them is different from -CF2CF2- and -CF2CF2CF2CF2-; - When z and z When both are 1, part of R CF and part of R F At least one of them is different from -CF2CF2CF2-.

8. The process according to claim 7, wherein, R CF It is a perfluoroalkyl chain containing 2 to 10 carbon atoms, optionally interrupted by one or more oxygen atoms; R F It is a perfluoroalkyl chain containing 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms; y is an integer such that the number-average molecular weight of the main chain of the polymer (PFPE), as determined by NMR analysis, is from 600 to 50,000.

9. The process according to claim 7, wherein, y is an integer such that the number-average molecular weight of the main chain of the polymer (PFPE), as determined by NMR analysis, is from 700 to 10,000.

10. The process according to claim 7, wherein, y is an integer such that the number-average molecular weight of the main chain of the polymer (PFPE), as determined by NMR analysis, is from 800 to 5,000.

11. A method for synthesizing a compound comprising the formula (R) as defined in claim 7. pf Polymers with a perfluorinated polyether backbone having two chain ends (PFPE) are called polymers. EST The process of (P) is the process (P) PFPE-EST ),in, At least one end of the chain contains at least one element of the formula -C(=O)OR alk The group, wherein R alk It is a straight-chain or branched alkyl chain containing 1 to 10 carbon atoms, and the process includes the following steps: (II) Making the at least one polymer (FH) as defined in any one of claims 1 to 6 b2 ( ) is contacted with at least one compound selected from the group consisting of F2C (=O), ClFC (=O), and BrFC (=O); (III) Contacting the at least one polymer obtained after step (II) with a fluorine source to provide a polymer (PFPE); and (IV) The at least one polymer obtained in step (III) is reacted with at least one having the formula R alk -OH compounds are contacted to provide polymer (PFPE) EST ), where R alk It is a straight-chain or branched alkyl chain containing 1 to 10 carbon atoms.

12. The process according to claim 11, wherein, The polymer (PFPE) EST It conforms to the following formula: (PFPE) EST-b2 ) Where R F R CF ,z,z And y is as defined in claim 7, and R alk It is as defined in claim 11.

13. The process according to claim 11, wherein, Both chain ends contain at least one group -C(=O)OR alk , where R alk It is a straight-chain or branched alkyl chain containing 1 to 10 carbon atoms.

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