(Per)fluoropolyether (PFPE) polymer

Abstract

The present invention relates to novel (per)fluoropolyether polymers which are characterized by a high molecular weight and a high functionality, a process for their preparation and their use as intermediate compounds in the preparation of further polymers.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of European Patent Application No. 19156266.9 filed on February 8, 2019, the entire contents of which are incorporated by reference into this application for all purposes. Technical Field

[0003] The present invention relates to novel (per)fluoropolyether (PFPE) polymers which are characterized by a high molecular weight and a high functionality, a process for their preparation and their use as intermediate compounds in the preparation of further polymers. Background Art

[0004] For many applications, difunctional (per)fluoropolyether polymers (PFPE) are known in the art, such as, for example, lubricants, surfactants, coating agents or as macromonomers in polycondensation reactions. In all of these applications, it is desirable to use difunctional PFPE with as high a difunctional content as possible. For example, in polycondensation reactions, it is necessary to use PFPE with a very high difunctional content in order to avoid random interruptions of the polymer chains (which is observed when relevant amounts of monofunctional PFPE are present).

[0005] However, bifunctional PFPE is typically available in a mixture with monofunctional and neutral (or non-functional) PFPE, due to the fact that the synthetic methods currently available for their manufacture do not allow obtaining pure bifunctional polymers. Therefore, in order to separate bifunctional PFPE from monofunctional and neutral PFPE, or to enrich the content of bifunctional PFPE, subsequent purification is required. For this purpose, purification methods have been developed and disclosed in the art, which methods typically include the use of solid adsorbent stationary phases and eluents (for example, refer to US 5246588 and US 7288682 in the name of Solvay Solexis SpA, US 5262057 and EP 0822216 in the name of Ausimont SpA).

[0006] Recently, a method for increasing the content of difunctional PFPE polymers in a mixture of neutral, monofunctional and difunctional PFPE polymers has been disclosed in WO 2013 / 060658 (in the name of Solvay Specialty Polymers Italy SpA), which method comprises using an adsorbent stationary phase and a supercritical fluid as mobile phase.

[0007] In addition to the above, another problem with the synthesis of PFPE polymers is the difficulty in obtaining PFPE polymers with high molecular weight. Indeed, the currently available synthesis methods allow obtaining PFPE with a number average molecular weight (Mn) generally ranging from 400 to 5,000.

[0008] In this regard, US 5,354,922 (in the name of Oseimont Co., Ltd.) discloses the possibility of obtaining peroxyperfluoropolyoxyalkylenes having a viscosity ranging from 300,000 to 8,000,000 cSt at 20°C, which provide, by chemical reduction, neutral perfluoropolyoxyalkylene polymers having a functionality greater than 1.9 and at the same time having a high molecular weight. More particularly, the perfluoropolyoxyalkylenes obtained by chemical reduction are said to have a number average molecular weight ranging from 400 to 20,000, and a functionality ranging from 1.99 to 1.88, respectively. However, on the one hand, peroxyperfluoropolyoxyalkylenes have a viscosity of 100,000 cSt or more at 20°C, which is very difficult to handle on an industrial scale. For viscosities greater than 100,000 cSt at 20°C, the use of solvents is mandatory, which requires modification in the factory and then subsequent steps for handling the solvent. On the other hand, this patent exemplifies the synthesis of functional perfluoropolyoxyalkylene polymers having a number average molecular weight of up to 3,200.

[0009] In addition, WO 2008 / 122639 (in the name of Solvay Solexis) discloses a method for preparing functional perfluoropolyether polymers. The polymers are said to have a number average molecular weight between 200 and 8,000. However, only perfluoropolyether polymers with a number average molecular weight of 1,080 and 1,270 were prepared in the examples.

[0010] The above-mentioned documents in fact demonstrate that when a high functionality is desired, the final perfluoropolyether polymer is characterized by a low number average molecular weight.

[0011] PFPE with (Mn) ranging from 3,500-5,000 are usually separated from mixtures containing PFPE with lower molecular weight. This problem and the separation of monofunctional PFPE with high molecular weight is disclosed in, for example, WO 2016 / 083280 (in the name of Solvay Specialty Polymers Italia).

[0012] WO 2016 / 083279 (in the name of Solvay Specialty Polymers Italia) discloses in Example 4 that Z DOL PFPE with nonafluorobutanesulfonate end groups The synthesis of a polymer obtained by the Z DOL PFPE reaction results in a polymer having, after thin layer distillation, a partially fluorinated backbone comprising three perfluoropolyether segments linked together by hydrogenated chains of formula -CH2OCH2- and a number average molecular weight of 8100 g / mol. No functionality is indicated for this polymer. Summary of the invention

[0013] The Applicant has now faced the problem of providing (per)fluoropolyether polymers which are characterized by both a high number average molecular weight (ie a number average molecular weight of from about 7,000 and up to 30,000) and a high functionality (ie at least 1.80).

[0014] Although PFPE polymers with number average molecular weights up to 10,000 have been disclosed in the art, the Applicant is fully aware that when preparing PFPE polymers by photo-oxidation of tetrafluoroethylene, a balance must be found between the desired molecular weight and the desired functionality. In fact, in order to obtain a mixture of PFPE polymers characterized by a high functionality (such as, for example, at least 1.80), the number average molecular weight of the final PFPE polymer will not be greater than 1,500. On the other hand, if a higher number average molecular weight is desired, starting materials with a smaller amount of peroxide oxygen (PO) should be used, thus negatively affecting the final functionality value. To date, the Applicant is not aware of any photo-oxidation process applicable on an industrial scale that allows obtaining bifunctional PFPE polymers with a number average molecular weight of 7,000 or more.

[0015] Furthermore, the Applicant was faced with the problem of providing (per)fluoropolyether polymers characterized by both a high number-average molecular weight and a high functionality, without requiring a purification step of the mixture comprising neutral, monofunctional and difunctional PFPE polymers. Indeed, as the number-average molecular weight of the PFPE polymers increases, the difficulty of finding separation techniques that can effectively separate neutral, monofunctional and difunctional polymers on an industrial scale also increases.

[0016] Furthermore, the Applicant was faced with the problem of providing (per)fluoropolyether polymers characterized by both a high number-average molecular weight and a high functionality, the backbone of which still comprises units of the formula -(CF2O)-. Indeed, the C1-recurring units provide the final PFPE polymer with specific low-temperature properties, compared to PFPE polymers whose backbone comprises only recurring units of the formula -(CF2CF2CF2O)- or -[CF(CF3)CF2O]-.

[0017] Unexpectedly, the applicant has discovered that a polymer characterized by a number average molecular weight (Mn) of at least 7,000 Daltons (e.g., 19Perfluoropolyether polymers having a functionality (F) of at least 1.80 (measured by F-NMR) can be prepared by a convenient method that can be easily implemented on an industrial scale and does not require separation and purification steps.

[0018] Therefore, in a first aspect, the present invention relates to a method for producing a polymer (PFPE) as defined below EST ) [method (P)],

[0019] The method comprises the following steps:

[0020] (I) reacting at least one perfluoropolyether diol [polymer (PFPE)] having a functionality of at least 1.90 with at least one perfluoro-bis-vinyl ether [compound (F)] to provide at least one partially fluorinated polyether polymer [polymer (HFPE)] comprising a partially fluorinated polyether backbone having two chain ends [chain (E HFPE )], the chain (E HFPE ) contains a -OH group, and the other chain (E HFPE ) comprises a group selected from -OH, -F, -CF3 or -COOH,

[0021] wherein the equivalent ratio between the polymer (PFPE) and the compound (F) is greater than 1;

[0022] (II) contacting the at least one polymer (HFPE) obtained in step (I) with at least one compound selected from perfluorinated anhydrides, perfluorinated carboxylic acids, carbonyl difluorides, perfluoroacyl fluorides or perfluoroacyl chlorides to provide at least one partially fluorinated polyether polymer [polymer (HFPE) P )] comprising a partially fluorinated polyether backbone having two chain ends [chain (E HFPE-P )], the chain (E HFPE-P ) contains an ester group or a fluoroformate, and the other chain (E HFPE-P ) comprises an ester group, a fluoroformate, or a group having the formula -F, -CF3 or -COOH;

[0023] (III) subjecting the at least one polymer (HFPE) obtained in step (II) to P ) is contacted with at least one fluorine source to provide at least one fully fluorinated polyether polymer [polymer (PFPE P )] comprising a fully fluorinated polyether backbone having two chain ends [chain (E PFPE-P )], the chain (E PFPE-P ) contains at least one group -OC(=O)R3 , where R 3 is -F, -CF3 or a linear or branched perfluorinated alkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by oxygen atoms, and the other chain (E PFPE-P ) contains a group having the formula -F, -CF3 or a group -OC(=O)R 3 , where R 3 is as defined above;

[0024] (IV) making the at least one polymer (PFPE P ) is contacted with a compound comprising at least one group capable of providing nucleophilic substitution to provide a perfluoropolyether polymer [polymer (PFPE EST )] comprising a fully fluorinated main chain having two chain ends [chain (E PFPE-EST )], the chain (E PFPE-EST ) contains at least one of the formula -C(=O)X 1 A group in which X 1 is -OH or an alkoxy chain containing from 1 to 6 carbon atoms, and the other chain (E PFPE-EST ) comprises a compound having the formula -F, -CF3 or -C(=O)X 1 A group in which X 1 is defined as above,

[0025] And wherein the main chain conforms to the following formula:

[0026] -(CFX # ) z1 O(R f )(CFX ＊ ) z2 D F ＊ -[O-CF2CF2(CF2) z OR CF -O(CF2) z＊ CF2CF2-R pf-F ] t -

[0027] in:

[0028] t is an integer from 1 to 30, preferably from 1 to 25, more preferably from 1 to 20,

[0029] z and z ＊ Each of is independently 0 or 1;

[0030] z1 is an integer equal to or greater than 1;

[0031] z2 is 0 or an integer equal to or greater than 1;

[0032] X # and X ＊ , which are the same or different from each other, are -F or -CF3, provided that when z1 and / or z2 is greater than 1, X # and X ＊ Yes - F;

[0033] D F ＊ is a perfluorinated alkylene chain containing from 1 to 6, more preferably from 1 to 3 carbon atoms, said alkyl chain optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms;

[0034] R CF is a perfluoroalkyl chain comprising from 2 to 12, preferably from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms;

[0035] (R f ) comprises, preferably consists of, repeating units R° independently selected from the group consisting of:

[0036] (i) -CFXO-, where X is F or CF3;

[0037] (ii) -CFXCFXO-, where X is the same or different at each occurrence and is F or CF3, provided that at least one of X is -F;

[0038] (iii) -CF2CF2CF2O-;

[0039] (iv) -CF2CF2CF2CF2O-;

[0040] (v)-(CF2) j -CFZ-O-, wherein j is an integer from 0 to 3 and Z is a molecule having the general formula -OR (f-a) -T group, where R (f-a) is a fluoropolyoxyalkylene chain containing from 0 to 10 repeating units, the repeating units being selected from the following: -CFXO-, -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, wherein each X is independently F or CF3 and T is a C1-C3 perfluoroalkyl group;

[0041] R pf-F is a chain with the following formula:

[0042] -OD F -(CFX # ) z1 -O(R f )(CFX ＊ )z2 -

[0043] in

[0044] z1, z2, X # , X ＊ and (R f ) is as defined above;

[0045] D F is a perfluorinated alkylene chain containing from 1 to 6, more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms.

[0046] The Applicant has surprisingly found that the above-mentioned process (P) allows obtaining partially and fully fluorinated polyether polymers characterized by a novel chemical structure.

[0047] Thus, in a second aspect, the present invention relates to a polymer (HFPE) comprising a polymer having two chain ends [chain (E HFPE )] partially fluorinated polyether backbone,

[0048] The main chain conforms to the following formula:

[0049] -D(CFX # ) z1 O(R f )(CFX ＊ ) z2 D ＊ -[OCF2CFH(CF2) z OR CF -O(CF2) z＊ CFHCF2-R pf ] t -in

[0050] t is an integer from 1 to 30;

[0051] z and z ＊ Each of is independently 0 or 1;

[0052] R CF is a perfluoroalkyl chain comprising from 1 to 12, preferably from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms;

[0053] z1 and z2 are the same or different from each other and are integers equal to or greater than 1;

[0054] X # and X ＊ , which are the same or different from each other, are -F or -CF3, provided that when z1 and / or z2 is greater than 1, X # and X ＊Yes - F;

[0055] D and D ＊ , which are identical or different from each other, are a sigma bond or an alkylene chain containing from 1 to 6, more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally substituted with at least one perfluoroalkyl group containing from 1 to 3 carbon atoms;

[0056] R pf is a chain with the following formula:

[0057] -OD-(CFX # ) z1 -O(R f )(CFX ＊ ) z2 -D ＊ -

[0058] where z1, z2, X # , X ＊ , D and D ＊ is as defined above; and

[0059] (R f ) comprises, preferably consists of, repeating units R° selected from the group consisting of formulae (i) to (v) as defined above.

[0060] Advantageously, in said polymer (HFPE), at least 90% of said chain ends comprise a group of formula -OH. The functionality (F HFPE-OH ) is calculated according to the equation reported above:

[0061] F HFPE-OH =2 ＊ E f / (E f +E n )

[0062] in

[0063] E f is the number of -OH terminal groups and

[0064] E n is the number of -F, -CF3 and -COOH terminal groups.

[0065] Advantageously, the polymer (HFPE) is characterized by a molecular weight of at least 7,000 Daltons (e.g., 19F-NMR), preferably at least 9,000 Daltons, more preferably at least 9,500 Daltons. Preferably, the polymer (HFPE) is characterized by a number average molecular weight (Mn) of 30,000 Daltons or less, more preferably up to 25,000 Daltons, even more preferably up to 20,000 Daltons.

[0066] Advantageously, the polymer (HFPE) is characterized by a functionality (F) of at least 1.80, more preferably at least 1.85, even more preferably at least 1.89, and still more preferably at least 1.92. Preferred embodiments have a functionality of at least 1.95.

[0067] In a third aspect, the present invention relates to a polymer (HFPE P ) comprising a partially fluorinated backbone as defined above for polymer (HFPE) having two chain ends [chain (E HFPE-P )], the chain (E HFPE-P ) contains at least one group -OC(=O)R 3 , where R 3 is -F, -CF3 or a linear or branched perfluorinated alkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by oxygen atoms, and the other chain end contains a group -OC(=O)R3, wherein R3 is as defined above or is a group of formula -F, -CF3 or -COOH.

[0068] For polymers (HFPE P ) functionality (F HFPE-P ) is calculated according to the equation reported above:

[0069] F HFPE-P =2 ＊ E f / (E f +E n )

[0070] in

[0071] E f is the group -OC(=O)R 3 The number of 3 is -F or -CF3, and

[0072] E n is the number of -F, -CF3 and -COOH terminal groups.

[0073] Advantageously, the polymer (HFPE P ) is characterized by at least 7,000 Daltons (e.g., by 19Preferably, the polymer (HFPE) has a number average molecular weight (Mn) of at least 9,000 Daltons, more preferably at least 9,500 Daltons, as measured by F-NMR. P ) is characterized by a number average molecular weight (Mn) of 30,000 Daltons or less, more preferably up to 25,000 Daltons, even more preferably up to 20,000 Daltons.

[0074] Advantageously, the polymer (HFPE P ) is characterized by a functionality (F) of at least 1.80, more preferably at least 1.85, even more preferably at least 1.89, and still more preferably at least 1.92. Preferred embodiments have a functionality of at least 1.95.

[0075] In a fourth aspect, the present invention relates to a polymer (PFPE) as defined above P ), which comprises a fully fluorinated polyether backbone having two chain ends [chain (E PFPE-P )],and

[0076] The main chain conforms to the following formula:

[0077] -(CFX # ) z1 O(R f )(CFX ＊ ) z2 D F ＊ -[O-CF2CF2(CF2) z OR CF -O(CF2)z*CF2CF2-R pf-F ] t -

[0078] in

[0079] t is an integer from 1 to 30,

[0080] z and z ＊ Each of is independently 0 or 1;

[0081] z1 is an integer equal to or greater than 1;

[0082] z2 is 0 or an integer equal to or greater than 1;

[0083] X # and X ＊ , which are the same or different from each other, are -F or -CF3, provided that when z1 and / or z2 is greater than 1, X # and X ＊ Yes - F;

[0084] D F＊ is a perfluorinated alkylene chain containing from 1 to 6, more preferably from 1 to 3 carbon atoms, said alkyl chain optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms;

[0085] R CF is a perfluoroalkyl chain comprising from 2 to 12, preferably from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms;

[0086] (R f ) comprises, preferably consists of, repeating units R° independently selected from the group consisting of:

[0087] (i) -CFXO-, where X is F or CF3;

[0088] (ii) -CFXCFXO-, where X is the same or different at each occurrence and is F or CF3, provided that at least one of X is -F;

[0089] (iii) -CF2CF2CF2O-;

[0090] (iv) -CF2CF2CF2CF2O-;

[0091] (v)-(CF2) j -CFZ-O-, wherein j is an integer from 0 to 3 and Z is a molecule having the general formula -OR (f-a) -T group, where R (f-a) is a fluoropolyoxyalkylene chain containing from 0 to 10 repeating units, the repeating units being selected from the following: -CFXO-, -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, wherein each X is independently F or CF3 and T is a C1-C3 perfluoroalkyl group;

[0092] R pf-F is a chain with the following formula:

[0093] -OD F -(CFX # ) z1 -O(R f )(CFX ＊ ) z2 -D F ＊ -

[0094] in

[0095] z1, z2, X # , X ＊ and (R f ) is as defined above;

[0096] D F and D F ＊ , which are the same or different from each other, are perfluorinated alkylene chains containing from 1 to 6, more preferably from 1 to 3 carbon atoms, said alkyl chain being optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms.

[0097] For polymers (PFPE P ) functionality (F PFPE-P ) is calculated according to the equation reported above:

[0098] F PFPE-P =2 ＊ E f / (E f +E n )

[0099] in

[0100] E f is the group -OC(=O)R 3 The number of 3 is -F, -CF3 or a linear or branched perfluorinated alkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by oxygen atoms, and

[0101] E n It is the number of groups -F and -CF3.

[0102] Advantageously, the polymer (PFPE P ) is characterized by at least 7,000 Daltons (e.g., by 19 Preferably, the polymer (PFPE) has a number average molecular weight (Mn) of at least 9,000 Daltons, more preferably at least 9,500 Daltons, as measured by F-NMR. P ) is characterized by a number average molecular weight (Mn) of 30,000 Daltons or less, more preferably up to 25,000 Daltons, even more preferably up to 20,000 Daltons.

[0103] Advantageously, the polymer (PFPE P ) is characterized by a functionality (F) of at least 1.80, more preferably at least 1.85, even more preferably at least 1.89, and still more preferably at least 1.92 PFPE-P ). Preferred embodiments have a functionality of at least 1.95.

[0104] In a fifth aspect, the present invention relates to a perfluoropolyether polymer [polymer (PFPE) as defined above EST )].

[0105] Advantageously, the polymer (PFPE EST ) is characterized by at least 7,000 Daltons (e.g., by 19 Preferably, the polymer (PFPE) has a number average molecular weight (Mn) of at least 9,000 Daltons, more preferably at least 9,500 Daltons, as measured by F-NMR. EST ) is characterized by a number average molecular weight (Mn) of 30,000 Daltons or less, more preferably up to 25,000 Daltons, even more preferably up to 20,000 Daltons.

[0106] For polymers (PFPE EST ) functionality (F EST ) is calculated according to the equation reported above:

[0107] F EST =2 ＊ E f / (E f +E n )

[0108] in

[0109] E f is a group -C(=O)X 1 The number of X 1 is -OH or an alkoxy chain containing from 1 to 6 carbon atoms, and

[0110] E n is the number of -F and -CF3 groups.

[0111] Advantageously, the polymer (PFPE EST ) is characterized by a functionality (F) of at least 1.80, more preferably 1.85, even more preferably at least 1.89, and still more preferably at least 1.92 EST ). Preferred embodiments have a functionality of at least 1.95.

[0112] Advantageously, the polymer (PFPE EST ) can be further reacted to provide useful PFPE derivatives, such as PFPE containing one or more (poly)amino groups and one or more hydroxyl groups at its chain ends.

[0113] PFPEs containing hydroxyl groups are of particular interest in the present invention.

[0114] In another aspect, the present invention relates to a perfluoropolyether polymer [polymer (PFPE OHOH )], which comprises a polymer (PFPE P) provided by a fully fluorinated polyether backbone of the formula and having two chain ends bonded to opposite sides of the backbone [chain (E PFPE-OHOH )], the chain (E PFPE-OHOH ) contains a group of formula -CH2OH, and the other chain end contains a group of formula -CH2OH, -F, -CF3.

[0115] Advantageously, in the polymer (PFPE OHOH ), at least 90% of the chains (E HWHF ) contains a group having the formula -OH, or in other words, the polymer (PFPE OHOH ) has a functionality (F) of at least 1.80 OHOH ).

[0116] For polymers (PFPE OHOH ) functionality (F OHOH ) is calculated according to the equation reported above:

[0117] F OHOH =2 ＊ E f / (E f +E n )

[0118] in

[0119] E f is the number of -OH terminal groups and

[0120] E n is the number of -F, -CF3 terminal groups.

[0121] Advantageously, the polymer (PFPE OHOH ) is characterized by at least 7,000 Daltons (e.g., by 19 Preferably, the polymer (PFPE) has a number average molecular weight (Mn) of at least 9,000 Daltons, more preferably at least 9,500 Daltons, as measured by F-NMR. OHOH ) is characterized by a number average molecular weight (Mn) of 30,000 Daltons or less, more preferably up to 25,000 Daltons, even more preferably up to 20,000 Daltons.

[0122] Advantageously, the polymer (PFPE OHOH ) is characterized by a functionality (F) of at least 1.80, more preferably at least 1.85, even more preferably at least 1.89, and still more preferably at least 1.92. Preferred embodiments have a functionality of at least 1.95. DETAILED DESCRIPTION

[0123] For purposes of this specification and the following claims:

[0124] - the use of parentheses around an identifying symbol or number, for example in expressions like "polymer (P)" etc., has the sole purpose of making this symbol or number better distinguishable from the rest of the text, and therefore said parentheses may also be omitted;

[0125] - the acronym "PFPE" stands for "(per)fluoropolyether" and, when used as a noun, is intended to refer to the singular or plural form, depending on the context;

[0126] - the term "(per)fluoropolyether" is intended to indicate a fully or partially fluorinated polymer;

[0127] - The expression "functionality of the (per)fluoropolyether polymer" of the present invention is defined as the number of functional groups per polymer molecule of interest, according to the following equation:

[0128] F=2 ＊ E f / (E f +E n )

[0129] Among them, E f is the number of functional end groups of interest and E n is the number of perfluorinated terminal groups (notably including -F and -CF3 groups) plus the number of f The functionality (F) can be determined, for example, by 19 F-NMR confirmed (as disclosed in the experimental part).

[0130] Advantageously, the polymer (PFPE) used as starting material in process (P) of the invention comprises a perfluoropolyether backbone having two chain ends bonded to opposite sides of said backbone,

[0131] The main chain conforms to the following formula:

[0132] -D-(CFX # ) z1 -O(R f )(CFX ＊ ) z2 -D ＊ -

[0133] Among them, D ＊ , X # , X ＊ , z1, z2 and R f is defined as above

[0134] and wherein the chain end comprises at least one hydroxyl group or a group having the formula -F and -CF3,

[0135] The polymer (PFPE) is characterized by a functionality (F) of at least 1.90.

[0136] Advantageously, the functionality (F) of the polymer (PFPE) is at least 1.95 and even more preferably 1.99. The functionality (F) of the polymer (PFPE) is calculated according to the following equation:

[0137] F OH =2 ＊ E f / (E f +E n )

[0138] in

[0139] Ef is the number of -OH terminal groups

[0140] En is the number of -F and -CF3 terminal groups.

[0141] Preferably, the chain (R f ) conforms to the following formula:

[0142] (R f -I)

[0143] -[(CFX 1 O) g1 (CFX 2 CFX 3 O) g2 (CF2CF2CF2O) g3 (CF2CF2CF2CF2O) g4 ]-

[0144] in

[0145] -X 1 independently selected from -F and -CF3,

[0146] -X 2 , X 3 , which are the same or different from each other and, at each occurrence, are independently -F, -CF3, provided that at least one of X is -F;

[0147] - g1, g2, g3 and g4, identical or different from each other, are independently integers ≥ 0, such that g1+g2+g3+g4 is in the range of from 2 to 70, preferably from 2 to 60; if at least two of g1, g2, g3 and g4 are not zero, the different repeating units are statistically distributed along the chain as a whole.

[0148] More preferably, the chain (R f ) is selected from chains having the formula:

[0149] (R f -IIA)-[(CF2CF2O) a1 (CF2O) a2 ]-

[0150] in:

[0151] a1 and a2 are independently integers ≥ 0, such that the number average molecular weight is between 400 and 5,000, preferably between 500 and 3,000; both a1 and a2 are preferably not zero, wherein the ratio a1 / a2 is preferably comprised between 0.1 and 10;

[0152] (R f -IIB)-[(CF2CF2O) b1 (CF2O) b2 (CF(CF3)O) b3 (CF2CF(CF3)O) b4 ]-

[0153] in:

[0154] b1, b2, b3, b4 are independently integers ≥ 0, such that the number average molecular weight is between 400 and 5,000, preferably between 400 and 3,000; preferably, b1 is 0, b2, b3, b4> 0, wherein the ratio b4 / (b2+b3) ≥ 1;

[0155] (R f -IIC)-[(CF2CF2O) c1 (CF2O) c2 (CF2(CF2) cw CF2O) c3 ]-

[0156] in:

[0157] cw=1 or 2;

[0158] c1, c2 and c3 are independently integers ≥ 0, which are selected so that the number average molecular weight is between 400 and 5,000, preferably between 400 and 3,000; preferably, c1, c2 and c3 are all > 0, wherein the ratio c3 / (c1+c2) is generally lower than 0.2;

[0159] (R f -IID)-[(CF2CF(CF3)O) d ]-

[0160] in:

[0161] d is an integer > 0 such that the number average molecular weight is between 400 and 5,000, preferably between 400 and 3,000;

[0162] (R f -IIE)-[(CF2CF2C(Hal ＊ )2O) e1 -(CF2CF2CH2O) e2 -(CF2CF2CH(Hal ＊ )O) e3 ]-

[0163] in:

[0164] -Hal ＊ , being the same or different at each occurrence, is a halogen selected from a fluorine atom and a chlorine atom, preferably a fluorine atom;

[0165] e1, e2 and e3, identical or different from each other, are independently integers ≥ 0, such that the sum of (e1+e2+e3) is comprised between 2 and 50.

[0166] Still more preferably, the chain (R f ) conforms to the following formula (R f -III):

[0167] (R f -III)-[(CF2CF2O) a1 (CF2O) a2 ]-

[0168] in:

[0169] a1 and a2 are integers > 0, such that the number average molecular weight is between 400 and 5,000, preferably between 400 and 3,000, wherein the ratio a1 / a2 is generally comprised between 0.1 and 10, more preferably between 0.2 and 5.

[0170] Preferably, the compound (F) conforms to the following formula:

[0171] CF2=CF(CF2) z OR CF O(CF2) z *CF=CF2

[0172] in

[0173] z and z ＊ Each of is independently 0 or 1; and

[0174] R CF Has the same meaning as defined above for the polymer PFPE.

[0175] Preferred compounds (F) are those conforming to the following formulae (FI) to (F-VIII):

[0176] (FI)CF2=CFO(CF2)2OCF=CF2

[0177] (F-II)CF2=CFO(CF2)3OCF=CF2

[0178] (F-III)CF2=CFO(CF2)4OCF=CF2

[0179] (F-IV)CF2=CFCF2O(CF2)4OCF2CF=CF2

[0180] (FV)CF2=CFO-CF2O-(CF2)2O(CF2)2O-CF2O-CF=CF2

[0181] (F-VI)CF2=CFO-CF2O-(CF2)2O-CF2O-CF=CF2

[0182] (F-VII)CF2=CFO-CF2O-(CF2)3O-CF2O-CF=CF2

[0183] (F-VIII)CF2=CFO-CF2O-(CF2)4O-CF2O-CF=CF2

[0184] (F-IX)CF2=CFO-CF2CF2O-CF2CF2O-CF=CF2

[0185] The equivalent ratio between the polymer (PFPE) and the compound (F) can be determined according to the polymer (HFPE) and, most importantly, the final polymer (PFPE). OHOH ) can be appropriately selected according to the desired number average molecular weight.

[0186] Advantageously, the equivalent ratio between said polymer (PFPE) and said compound (F) is from 1.01 to 1.50, more preferably from 1.05 to 1.25.

[0187] Advantageously, said step (I) is carried out so that the functionality of the polymer (HFPE) is not less than 90%, preferably not less than 92%, even more preferably not less than 95% of the functionality of the starting polymer (PFPE).

[0188] Preferably, step (I) is carried out in the presence of a base, even more preferably in the presence of potassium carbonate.

[0189] Preferably, the step (I) is carried out in the presence of a polar aprotic solvent, and the polar aprotic solvent is more preferably selected from the group consisting of acetonitrile, tetrahydrofuran, dioxane, dimethoxyethane (glyme), bis (2-methoxyethyl) ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol dimethyl ether (tetraglyme), dimethyl sulfoxide, dimethylformamide, ethylene polyoxide dimethyl ether. Acetonitrile, tetrahydrofuran and dioxane are particularly preferred.

[0190] Step (I) can be carried out by adding the polymer (PFPE) to the compound (F), or vice versa, by adding the compound (F) to the polymer (PFPE).

[0191] Preferably, said step (I) is carried out at a temperature ranging from room temperature (ie about 25°C) to 90°C.

[0192] Preferably, said step (I) is carried out in the presence of a phase transfer catalyst (advantageously selected from tetraalkylammonium).

[0193] Advantageously, the step (I) is performed in an anhydrous reaction environment.

[0194] Preferably, after step (I), a polymer (HFPE) is provided which comprises essentially the following groups at its chain ends: -OH, -F, -CF3 and -COOH.

[0195] The expression "essentially comprises" is intended to indicate that the chain ends of the polymer (HFPE) may contain, in addition to the groups detailed above, a small amount of end groups derived by side reactions or impurities in the starting material, it being understood that the amount will be such as not to substantially modify the properties of the polymer (HFPE). For example, end groups other than -OH, -F, -CF3 and -COOH (such as the formula -CH2Cl) may be present in an amount of less than 1 mol%, more preferably less than 0.5 mol%, and even more preferably less than 0.1 mol%, based on the total amount of end groups in the polymer (HFPE).

[0196] It will be clear to a person skilled in the art that when the reaction conditions of the steps of process (P) of the invention are controlled, at the end of step (I), a mixture of polymers (HFPE) characterized by having different groups at their chain ends is obtained. However, the fact remains that the conditions of step (I) of process (P) of the invention are adjusted so as to provide a polymer (HFPE) characterized by a functionality as defined above.

[0197] The same principles apply and this also holds true for each of steps (II) to (IV) of process (P) according to the invention.

[0198] As will be clear to the skilled person, step (II) of process (P) of the present invention is intended to provide a polymer (HFPE) having protected chain ends. P ).

[0199] Preferably, the step (II) is carried out in the presence of trifluoroacetic anhydride or carbonyl fluoride.

[0200] Preferably, the fluorine source in step (III) is a gas containing fluorine atoms. More preferably, the fluorine source is fluorine gas (F2).

[0201] Advantageously, the fluorine source in step (III) is used in admixture with a diluent gas, which is preferably selected from inert gases such as helium and nitrogen.

[0202] Advantageously, said step (III) is carried out in the presence of a compound capable of generating fluorine radicals to facilitate the fluorination step.

[0203] Suitable compounds are selected from carbon monoxide and halogenated olefins.

[0204] The halogenated olefin can be selected from, for example, tetrafluoroethylene (TFE), hexafluoro-propylene (HFP), octafluorobutene, perfluoropentene, perfluorohexene, perfluoroheptene, perfluorooctene, perfluorocyclobutene, perfluorocyclopentene, perfluorocyclohexene, chlorotrifluoroethylene (CTFE), dichlorodifluoroethylene, chloropentafluoropropylene, perfluorobutadiene, perfluoro-methyl vinyl ether, perfluoro-ethyl vinyl ether, perfluoro-propyl vinyl ether; CF3OClC=CClF, trichloroethylene, tetrachloroethylene, dichloroethylene isomers; and fluorodioxole.

[0205] In said step (IV), said compound comprising at least one group capable of providing nucleophilic substitution is advantageously selected from water or an alcohol having from 1 to 6 carbon atoms (more preferably ethanol, methanol or propanol).

[0206] Polymer (PFPE OHOH ) is through the method [method (P OHOH )] is advantageously prepared, the method comprising:

[0207] (V) providing a polymer as defined in any one of the preceding claims (PFPE EST ),

[0208] (VI) making the polymer (PFPE EST ) is contacted with a reducing agent to hydrolyze the ester groups at the chain ends to groups -CH2OH, thereby providing a polymer (PFPE OHOH ).

[0209] Preferably, step (VI) is carried out in the presence of a base (such as sodium borohydride).

[0210] The applicant has further noted that the polymer (PFPE OHOH ) are useful as intermediates for the synthesis of additional bifunctional PFPE polymers.

[0211] In one aspect, the polymer (PFPE OHOH ) can be used as a macromonomer in a polycondensation reaction to provide a PFPE polymer containing polyurethane groups at its chain ends.

[0212] On the other hand, the polymer (PFPE OHOH ) to modify the groups at the chain ends thereof.

[0213] Notably, the polymer (PFPE OHOH ) is advantageously used for the synthesis of the above polymer (PFPE OHOH ) having a two-chain-terminal perfluoropolyether main chain polymer [polymer (PFPE OHOH-X )], wherein at least one chain end comprises a 1 The group,

[0214] Where R 1 is selected from the group comprising the following: a linear or branched alkyl chain comprising from 1 to 16 carbon atoms and substituted by at least 2, more preferably from 2 to 8, groups -OH; -(CH2CH2O) n H, wherein n is an integer from 1 to 10; -(CH2CH2O) n P(O)(OH)2, wherein n is 0 or an integer greater than 1; -CH2CH=CH2; -C(=O)-R 2 , where R 2 is a straight chain or branched chain alkyl group containing from 1 to 6 carbon atoms, an alkenyl group containing from 2 to 12 carbon atoms, or -NHR 4 (where R 4 is a hydrogen atom), a straight or branched alkyl chain containing from 1 to 20 carbon atoms; a phenyl group optionally substituted by at least one nitro group; and a pyridyl group optionally substituted by at least one -CF3 group.

[0215] Should the disclosure of any patents, patent applications, and publications incorporated by reference into this application conflict with the description of this application to the extent that it renders a term unclear, the description shall take precedence.

[0216] The present invention will now be described in more detail with reference to the following examples, the purpose of which is merely illustrative and not limiting the scope of the present invention.

[0217] Experimental Section

[0218] Material

[0219] The reagents used in the following examples were obtained from Sigma-Aldrich and used as received.

[0220] Perfluoro-bis-vinyl ether was obtained from Ftoran GmbH & Co. KG / ANLES, Ltd.

[0221] Novec TM 7100 Engineering Fluid (methoxy-nonafluorobutane-HFE 7100) was obtained from 3M Company and used as received.

[0222] Perfluoropolyoxyalkylene glycol conforming to the formula provided below Z PFPE polymers were obtained from Solvay Specialty Polymers Italy:

[0223] HOCH2CF2O(R f )CF2CH2OH

[0224] Among them (R f ) is -(CF2CF2O) a1 (CF2O) a2 -

[0225] where the ratio a2 / a1 is about 1, and

[0226] ＊ For polymer PFPE1: Mn = 1,034 Daltons and F = 1.99;

[0227] ＊ For polymer PFPE2: Mn = 3,045 Daltons and F = 1.98.

[0228] method

[0229] NMR analysis

[0230] In for 1 H at 499.86MHz and for 19 F recorded on an Agilent System 500 running at 470.30 MHz 19 F-NMR and 1 H-NMR spectrum.

[0231] Approximately 0.6 cc of each sample was introduced into an NMR tube and analyzed neat.

[0232] Use a pulse turning angle of 90° and a relaxation delay suitable for quantitative analysis (3-5 times the maximum d1 value, at least 6 s) to obtain 19 The F-NMR spectrum was selected to cover all signals from about -10 to -170 ppm. The number of scans was chosen to have a sufficient signal-to-noise ratio (at least 400).

[0233] Acquired at a spectral width of about 16 ppm, a pulse turning angle of 45°, and a relaxation delay suitable for quantitative analysis (3-5 times the maximum d1 value, at least 5 s) 1 H-NMR spectroscopy. The number of scans was chosen so as to have a sufficient signal-to-noise ratio (at least 100).

[0234] Both spectra were acquired at room temperature at a spinning rate of 20 Hz.

[0235] use 19 F-NMR spectroscopy determines the number average molecular weight (Mn) of the polymer. As is known in the art, this is made possible by the fact that 19 Each structure resonates at a different frequency in the F-NMR spectrum, and therefore they can be integrated separately. Therefore, the number average molecular weight M is calculated as follows using the integrated signals of the internal units (such as -(CF2CF2O)- and -(CF2O)-) and the chain end groups after normalization to the same number of fluorine atoms: n :

[0236] M n =2x[(Σ i U i ＊ M i ) / Σ t T t ]

[0237] in

[0238] U i is the integrated signal of the internal unit of the polymer,

[0239] M i The formula of each unit, and

[0240] T i The integrated signal at the end of the chain.

[0241] The relative amounts of the different chain ends (measured as defined above) also allow calculation of the functionality defined as follows:

[0242] F = 2x(E f / (E f +E n )

[0243] in

[0244] E f is the functional chain end of interest, and

[0245] E n It is a chain end different from Ef.

[0246] Example 1

[0247] Step 1

[0248] In a 250 ml three-necked flask equipped with a magnetic stirrer, 0.66 g of a 25% w / w solution of tetramethylammonium hydroxide in water (0.047 mmol) were introduced and 20 g (38.7 meq) of PFPE1 were added.

[0249] The mixture was heated at 80° C. for 1 hour under vacuum to completely remove water. After cooling at room temperature, 40 g of acetonitrile and 5.85 g (33.33 meq) of perfluoro-bis-vinyl ether having the following formula were added thereto:

[0250] CF2=CFOCF2CF2CF2OCF=CF2.

[0251] Then 2.7 g (19.5 moles) of anhydrous potassium carbonate were added in a single portion with stirring, and the reaction mixture was left at 50° C. with stirring for about seven hours. 19 When F-NMR analysis showed that the double bond signal of vinyl ether disappeared, the reaction was considered to be completed.

[0252] When the reaction is complete, the mixture is cooled to room temperature and washed with 50g of water. Thereafter, 37g of HFE7100 and 4g of isobutyl alcohol are added to the reaction mixture to obtain a two-phase separation. The organic phase is separated and washed with 20g of water and 3.6g of hydrochloric acid 37%. Two phases are obtained after decantation. The fluorinated phase (phase at the bottom) is evaporated under vacuum to provide 23.1g of a viscous transparent liquid.

[0253] pass 1 H-NMR and 19 The structure of the product determined by F-NMR is as follows:

[0254] X-CF2O-(R f )-OCF2CH2[OCF2CFHOC3F6OCFHCF2OCH2CF2O-(Rf)-OCF2CH 2]t OH

[0255] in

[0256] t=6.80

[0257] X=-CH2OH (95%), -F (2%), -COOH (3%),

[0258] Mn = 10,300 Daltons

[0259] (F OH )=1.90.

[0260] Step 2

[0261] 18.8 g of the polymer obtained in the above-mentioned Step 1 was charged into a 100 ml round-bottom flask equipped with a magnetic stirrer, and 1.5 g of trifluoroacetic anhydride was added.

[0262] The mixture was left under stirring at room temperature for 1 hour, and the trifluoroacetic acid formed and the excess anhydride were then distilled off at 80° C. under vacuum.

[0263] 18.3 g of a product having the following structure were obtained:

[0264] X-CF2O-(R f )-OCF2CH2[OCF2CFHOC3F6OCFHCF2OCH2CF2O-(Rf)-OCF2CH2] t OC(=O)CF3

[0265] in

[0266] t=6.80

[0267] X = -CH2OC(=O)CF3, -F and -COOH;

[0268] (F -OCOCF3 )=1.90.

[0269] Step 3

[0270] 18.3 g of the polymer obtained in step 2 above was dissolved in 92.5 g of perfluoro-2-butyltetrahydrofuran (C8F 16 The mixture was charged into a 250 ml stainless steel reactor equipped with a mechanical stirrer, a thermocouple and two inlet tubes and maintained at 0° C. by an external circulating bath.

[0271] While maintaining high-speed stirring, 6.0 Nl / h of helium are fed into the reactor through the first inlet pipe for 1 hour, and then 2.0 Nl / h of elemental fluorine are added to the same flow; after 2 hours, 0.3 Nl / h of carbon monoxide diluted in 1.5 Nl / h of helium has been fed into the reactor through the second inlet pipe; after another 4 hours, the elemental fluorine flow and the carbon monoxide flow are closed and the reactor is purged with the residual helium flow.

[0272] pass 1 H-NMR analyzes this crude mixture, to confirm the quantitative conversion of all hydrogen atoms.Then handle this mixture with excessive ethanol under reflux to convert all terminal perfluoroester groups into corresponding ethyl ester groups.This mixture is washed with water twice, then handled with sodium sulfate, and finally evaporated to remove perfluorinated solvent, and reclaim the product that meets the following formula:

[0273] XCF2O-(Rf)-OCF2[CF2OCF2CF2OC3F6OCF2CF2OCF2CF2O-(Rf)-OCF2] t -C(=O

[0274] )X1[III]

[0275] in

[0276] t=6.38

[0277] X=-COOEt(90.5%),-F(7.8%),-CF3(1.6%)

[0278] X1=-OEt

[0279] (F -COOET )=1.81

[0280] Mn=10,600.

[0281] Step 4

[0282] The polymer obtained in step 3 above is reduced from the ethyl ester end groups to the corresponding alcohol following the procedure reported in the following literature: A. Russo, C. Tonelli; Journal of Fluorine Chemistry 125 (2004) 181-188 to obtain the final polymer conforming to the following formula:

[0283] X-CF2O-(Rf)-OCF2[CF2OCF2CF2OC3F6OCF2CF2OCF2CF2O-(Rf)-OCF2] t CH2OH[IV]

[0284] in

[0285] t=6.38

[0286] X=-CH2OH、-F、-CF3

[0287] (F OHOH )=1.81

[0288] Mn = 10,500 Daltons.

[0289] Example 2

[0290] Step 1

[0291] In a 250 ml three-necked flask equipped with a magnetic stirrer, 0.3 g of a 25% w / w solution of tetramethylammonium hydroxide in water (0.823 mmol) are introduced and 25 g (16.3 meq) of PFPE2 are added.

[0292] The mixture was heated at 80° C. for 1 hour under vacuum. After cooling at room temperature, 35 g of acetonitrile and 2.45 g (14 meq) of perfluoro-bis-vinyl ether having the following formula were added thereto:

[0293] CF2=CFOCF2CF2CF2OCF=CF2.

[0294] Then, 1.18 g (8.55 moles) of anhydrous potassium carbonate were added in a single portion with stirring, and the reaction mixture was left at 50° C. with stirring for about seven hours. 19 When F-NMR analysis showed that the double bond signal of vinyl ether disappeared, the reaction was considered to be completed.

[0295] When the reaction is complete, the mixture is cooled to room temperature and washed with 50g of water. After this, 37g of HFE7100 and 4g of isobutyl alcohol are added to the reaction mixture to obtain a two-phase separation. The organic phase is separated and washed with 20g of water and 3.6g of hydrochloric acid 37%. Two phases are obtained after decantation. The fluorinated phase (phase at the bottom) is evaporated under vacuum to provide 23g of a viscous transparent liquid.

[0296] pass 1 H-NMR and 19 The structure of the product determined by F-NMR is as follows:

[0297] X-CF2O-(R f )-OCF2CH2[OCF2CFHOC3F6OCFHCF2OCH2CF2O-(Rf)-OCF2CH2] t OH

[0298] in

[0299] t=6.04

[0300] X=-CH2OH,-F,-CF3,-COOH,

[0301] Mn = 23,560 Daltons,

[0302] (F OH )=1.95.

[0303] Example 3

[0304] Step 1

[0305] The same procedure disclosed in Example 1 - Step 1 was followed, but using the following reactants:

[0306] 20g (38.7meq) of PFPE2

[0307] 0.66 g of tetramethylammonium hydroxide 25% w / w solution in water (1.8 mmol).

[0308] 22.6 g of a viscous, clear liquid were obtained.

[0309] pass 1 H-NMR and 19 The structure of the product determined by F-NMR is as follows:

[0310] X-CF2O-(R f )-OCF2CH2[OCF2CFHOC3F6OCFHCF2OCH2CF2O-(Rf)-OCF2CH2] t OH

[0311] in

[0312] t = 17.12,

[0313] X=-CH2OH,-F,-CF3,-COOH,

[0314] Mn = 24,940 Daltons,

[0315] (F OH )=1.90.

Claims

1. A perfluoropolyether polymer [polymer (PFPE EST )] comprising a fully fluorinated main chain having two chain ends [chain (E PFPE-EST )], The chain (E PFPE-EST ) contains at least one group having the formula -C(=O)X 1 , where X 1 is -OH or an alkoxy chain containing from 1 to 6 carbon atoms, and the other chain (E PFPE-EST ) comprises a compound having the formula -F, -CF3 or -C(=O)X 1 A group in which X 1 is defined as above, And wherein the main chain conforms to the following formula: -(CFX # ) z1 O(R f )(CFX ＊ ) z2 D F ＊ -[O-CF2CF2(CF2) z O-R CF -O(CF2) z＊ CF2CF2-R pf-F ] t - in: t is an integer from 1 to 30, z and z ＊ Each of is independently 0 or 1; z1 is an integer equal to or greater than 1; z2 is 0 or an integer equal to or greater than 1; X # and X ＊ , which are the same or different from each other, are -F or -CF3, provided that when z1 and / or z2 is greater than 1, X # and X ＊ Yes - F; D F ＊ is a perfluorinated alkylene chain containing from 1 to 6 carbon atoms, said alkyl chain optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms; R CF is a perfluoroalkyl chain containing from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; (R f ) comprises repeating units R°, said repeating units R° being independently selected from the group consisting of: (i) -CFXO-, where X is F or CF3; (ii) -CFXCFXO-, where X is the same or different at each occurrence and is F or CF3, provided that at least one of X is -F; (iii) -CF2CF2CF2O-; (iv) -CF2CF2CF2CF2O-; (v)-(CF2) j -CFZ-O-, wherein j is an integer from 0 to 3 and Z is a molecule having the general formula -OR (f-a) -T group, where R (f-a) is a fluoropolyoxyalkylene chain containing from 0 to 10 repeating units, the repeating units being selected from the following: -CFXO-, -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, wherein each X is independently F or CF3 and T is a C1-C3 perfluoroalkyl group; R pf-F is a chain with the following formula: -OD F -(CFX # ) z1 -O(R f )(CFX ＊ ) z2 - in z1, z2, X # , X ＊ and (R f ) is as defined above; D F is a perfluorinated alkylene chain containing from 1 to 6 carbon atoms, said alkyl chain being optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms.

2. The polymer according to claim 1 (PFPE EST ), the polymer having a number average molecular weight (Mn) from 7,000 Daltons and up to 30,000 Daltons, according to 19 F-NMR measurements.

3. The polymer according to claim 1 (PFPE EST ), the polymer having a functionality F of at least 1.80 EST .

4. The polymer according to claim 1 (PFPE EST ), where t is an integer from 1 to 25.

5. The polymer according to claim 1 (PFPE EST ), where t is an integer from 1 to 20.

6. The polymer according to claim 1 (PFPE EST ), where D F ＊ is a perfluorinated alkylene chain containing from 1 to 3 carbon atoms.

7. The polymer according to claim 1 (PFPE EST ), where R CF is a perfluoroalkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms.

8. The polymer according to claim 1 (PFPE EST ), where (R f ) consists of repeating units R°.

9. The polymer according to claim 1 (PFPE EST ), where D F is a perfluorinated alkylene chain containing from 1 to 3 carbon atoms.

10. The polymer according to claim 2 (PFPE EST ), wherein the polymer has a number average molecular weight (Mn) from 9,000 Daltons and up to 30,000 Daltons.

11. The polymer according to claim 3 (PFPE EST ), the polymer having a functionality F of at least 1.85 EST .

12. A partially fluorinated polyether polymer [polymer (HFPE)] comprising a partially fluorinated polyether backbone having two chain ends [chain (E HFPE )], the chain (E HFPE ) contains a -OH group, and the other chain (E HFPE ) comprises a group selected from -OH, -F, -CF3 or -COOH, The main chain conforms to the following formula: -D(CFX # ) z1 O(R f )(CFX ＊ ) z2 D ＊ -[OCF2CFH(CF2) z O-R CF -O(CF2) z＊ CFHCF2-R pf t - wherein​ t is an integer from 1 to 30; z and z ＊ Each of is independently 0 or 1; R CF is a perfluoroalkyl chain containing from 1 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; z1 and z2 are the same or different from each other and are integers equal to or greater than 1; X # and X ＊ , which are the same or different from each other, are -F or -CF3, provided that when z1 and / or z2 is greater than 1, X # and X ＊ Yes - F; D and D ＊ , which are the same or different from each other, are a sigma bond or an alkylene chain containing from 1 to 6 carbon atoms, said alkyl chain being optionally substituted with at least one perfluoroalkyl group containing from 1 to 3 carbon atoms; R pf is a chain with the following formula: -OD-(CFX # ) z1 -O(R f )(CFX ＊ ) z2 -D ＊ - where z1, z2, X # , X ＊ , D and D ＊ is as defined above; and (R f ) comprises repeating units R° selected from the group consisting of formulae (i) to (v) as defined in claim 1.

13. The polymer (HFPE) according to claim 12, having a number average molecular weight (Mn) of from 7,000 Daltons and up to 30,000 Daltons, according to 19 F-NMR measurement; and / or a functionality F of at least 1.80 HFPE-OH .

14. The polymer (HFPE) according to claim 12, wherein R CF is a perfluoroalkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms.

15. The polymer (HFPE) according to claim 12, wherein D and D ＊ , which are the same or different from each other, contain an alkylene chain of from 1 to 3 carbon atoms.

16. The polymer (HFPE) according to claim 12, wherein (R f ) consists of repeating units R°.

17. The polymer (HFPE) according to claim 13, wherein the polymer has a number average molecular weight (Mn) of from 9,000 Daltons and up to 30,000 Daltons.

18. The polymer (HFPE) of claim 13, wherein the polymer has a functionality F of at least 1.

85. HFPE-OH .

19. A partially fluorinated polyether polymer [polymer (HFPE P )] comprising a partially fluorinated main chain having two chain ends [chain (E HFPE-P )], the chain (E HFPE-P ) contains at least one group -OC(=O)R 3 , where R 3 is -F, -CF3 or a linear or branched perfluorinated alkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by oxygen atoms, and the other chain end contains a group -OC(=O)R3, wherein R3 is as defined above or is a group of formula -F, -CF3 or -COOH; the main chain conforms to the following formula: -D(CFX # ) z1 O(R f )(CFX ＊ ) z2 D ＊ -[OCF2CFH(CF2) z O-R CF -O(CF2) z＊ CFHCF2-R pf ] t - in t, z, z ＊ , R CF , X # , X ＊ ,D,D ＊ and R pf As defined in claim 12.

20. The polymer according to claim 19 (HFPE P ), the polymer having a number average molecular weight (Mn) from 7,000 Daltons and up to 30,000 Daltons, according to 19 F-NMR measurement; and / or a functionality F of at least 1.80 HFPE-P .

21. The polymer according to claim 20 (HFPE P ), the polymer having a number average molecular weight (Mn) from 9,000 Daltons and up to 30,000 Daltons.

22. The polymer according to claim 20 (HFPE P ), the polymer having a functionality F of at least 1.85 HFPE-P .

23. A fully fluorinated polyether polymer [polymer (PFPE P )] comprising a fully fluorinated polyether backbone having two chain ends [chain (E PFPE-P )], the chain (E PFPE-P ) contains at least one group -OC(=O)R 3 , where R 3 is -F, -CF3 or a linear or branched perfluorinated alkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by oxygen atoms, and the other chain (E PFPE-P ) contains a group having the formula -F, -CF3 or a group -OC(=O)R 3 , where R 3 is as defined above; The main chain conforms to the following formula: -(CFX # ) z1 O(R f )(CFX ＊ ) z2 D F ＊ -[O-CF2CF2(CF2) z O-R CF -O(CF2) z＊ CF2CF2-R pf-F ] t - in t is an integer from 1 to 30, z and z ＊ Each of is independently 0 or 1; z1 is an integer equal to or greater than 1; z2 is 0 or an integer equal to or greater than 1; X # and X ＊ , which are the same or different from each other, are -F or -CF3, provided that when z1 and / or z2 is greater than 1, X # and X ＊ Yes - F; D F ＊ is a perfluorinated alkylene chain containing from 1 to 6 carbon atoms, said alkyl chain optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms; R CF is a perfluoroalkyl chain containing from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; (R f ) comprises repeating units R°, said repeating units R° being independently selected from the group consisting of: (i) -CFXO-, where X is F or CF3; (ii) -CFXCFXO-, where X is the same or different at each occurrence and is F or CF3, provided that at least one of X is -F; (iii) -CF2CF2CW2O-, wherein each W, being the same as or different from each other, is F; (iv) -CF2CF2CF2CF2O-; (v)-(CF2) j -CFZ-O-, wherein j is an integer from 0 to 3 and Z is a molecule having the general formula -OR (f-a) -T group, where R (f-a) is a fluoropolyoxyalkylene chain containing from 0 to 10 repeating units, the repeating units being selected from the following: -CFXO-, -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, wherein each X is independently F or CF3 and T is a C1-C3 perfluoroalkyl group; R pf-F is a chain with the following formula: -OD F -(CFX # ) z1 -O(R f )(CFX ＊ ) z2 -D F ＊ - in z1, z2, X # , X ＊ and (R f ) is as defined above; D F and D F ＊ , which are the same or different from each other, are perfluorinated alkylene chains containing from 1 to 6 carbon atoms, said alkyl chain being optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms.

24. The polymer according to claim 23 (PFPE P ), the polymer having a number average molecular weight (Mn) from 7,000 Daltons and up to 30,000 Daltons, according to 19 F-NMR measurement; and / or a functionality F of at least 1.80 HFPE-P .

25. The polymer according to claim 23 (PFPE P ), where D F ＊ is a perfluorinated alkylene chain containing from 1 to 3 carbon atoms.

26. The polymer according to claim 23 (PFPE P ), where R CF is a perfluoroalkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms.

27. The polymer according to claim 23 (PFPE P ), where (R f ) consists of repeating units R°.

28. The polymer according to claim 23 (PFPE P ), where D F and D F ＊ , which are the same or different from each other, are perfluorinated alkylene chains containing from 1 to 3 carbon atoms.

29. The polymer according to claim 24 (PFPE P ), wherein the polymer has a number average molecular weight (Mn) from 9,000 Daltons and up to 30,000 Daltons.

30. The polymer according to claim 24 (PFPE P ), the polymer having a functionality F of at least 1.85 HFPE-P .

31. A method for producing a polymer (PFPE) according to claim 1 EST ) [method (P)], The method comprises the following steps: (I) reacting at least one perfluoropolyether diol [polymer (PFPE)] having a functionality of at least 1.90 with at least one perfluoro-bis-vinyl ether [compound (F)] to provide at least one partially fluorinated polyether polymer [polymer (HFPE)] comprising a partially fluorinated polyether backbone having two chain ends [chain (E HFPE )], the chain (E HFPE ) contains a -OH group, and the other chain (E HFPE ) comprises a group selected from -OH, -F, -CF3 or -COOH, wherein the equivalent ratio between the polymer (PFPE) and the compound (F) is greater than 1; (II) contacting the at least one polymer (HFPE) obtained in step (I) with at least one compound selected from perfluorinated anhydrides, perfluorinated carboxylic acids, carbonyl difluorides, perfluoroacyl fluorides or perfluoroacyl chlorides to provide at least one partially fluorinated polyether polymer [polymer (HFPE) P )] comprising a partially fluorinated polyether backbone having two chain ends [chain (E HFPE-P )], the chain (E HFPE-P ) contains an ester group or a fluoroformate, and the other chain (E HFPE-P ) comprises an ester group, a fluoroformate, or a group having the formula -F, -CF3 or -COOH; (III) subjecting the at least one polymer (HFPE) obtained in step (II) to P ) is contacted with at least one fluorine source to provide at least one fully fluorinated polyether polymer [polymer (PFPE P )] comprising a fully fluorinated polyether backbone having two chain ends [chain (E PFPE-P )], the chain (E PFPE-P ) contains at least one group -OC(=O)R 3 , where R 3 is -F, -CF3 or a linear or branched perfluorinated alkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by oxygen atoms, and the other chain (E PFPE-P ) contains a group having the formula -F, -CF3 or a group -OC(=O)R 3 , where R 3 is as defined above; (IV) making the at least one polymer (PFPE P ) is contacted with a compound comprising at least one group capable of providing nucleophilic substitution to provide a perfluoropolyether polymer [polymer (PFPE EST )].

32. The method (P) according to claim 31, wherein: The compound (F) conforms to the following formula: CF2=CF(CF2) z OR CF O(CF2) z＊ CF=CF2 in z and z ＊ Each of is independently 0 or 1; and R CF is a perfluoroalkyl chain containing from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms.

33. The method (P) according to claim 32, wherein R CF is a perfluoroalkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms.

34. The method (P) according to claim 31, wherein: The equivalent ratio between the polymer (PFPE) and the compound (F) is from 1.01 to 1.

50.

35. Method (P) according to claim 34, wherein the equivalence ratio is from 1.05 to 1.

25.

36. The method (P) according to any one of claims 31 to 35, wherein: Carry out the step (I): - in the presence of a base; and / or - in the presence of a polar aprotic solvent; and / or - at a temperature in the range from room temperature to 90°C; and / or - in the presence of a phase transfer catalyst; and / or - In anhydrous reaction environment.

37. The method (P) according to any one of claims 31 to 35, wherein: The step (I) is carried out so that the functionality of the polymer (HFPE) is not less than 90% of the functionality of the polymer (PFPE).

38. The method (P) according to claim 37, wherein: The functionality of the polymer (HFPE) is not less than 92% of the functionality of the polymer (PFPE).

39. The method (P) according to claim 37, wherein: The functionality of the polymer (HFPE) is not less than 95% of the functionality of the polymer (PFPE).

40. The method (P) according to claim 36, wherein: The room temperature is 25°C.

41. A perfluoropolyether polymer [polymer (PFPE OHOH )] comprising a fully fluorinated polyether backbone having two chain ends [chain (E PFPE-OHOH )], the chain (E PFPE-OHOH ) at least one of which contains a group of formula -CH2OH, and the other chain end contains a group of formula -CH2OH, -F, -CF3; The main chain conforms to the following formula: -(CFX # ) z1 O(R f )(CFX ＊ ) z2 D F ＊ -[O-CF2CF2(CF2) z O-R CF -O(CF2) z＊ CF2CF2-R pf-F ] t - in t is an integer from 1 to 30, z and z ＊ Each of is independently 0 or 1; z1 is an integer equal to or greater than 1; z2 is 0 or an integer equal to or greater than 1; X # and X ＊ , which are the same or different from each other, are -F or -CF3, provided that when z1 and / or z2 is greater than 1, X # and X ＊ Yes - F; D F ＊ is a perfluorinated alkylene chain containing from 1 to 6 carbon atoms, said alkyl chain optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms; R CF is a perfluoroalkyl chain containing from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; (R f ) comprises repeating units R°, said repeating units R° being independently selected from the group consisting of: (i) -CFXO-, where X is F or CF3; (ii) -CFXCFXO-, where X is the same or different at each occurrence and is F or CF3, provided that at least one of X is -F; (iii) -CF2CF2CW2O-, wherein each W, being the same as or different from each other, is F; (iv) -CF2CF2CF2CF2O-; (v)-(CF2) j -CFZ-O-, wherein j is an integer from 0 to 3 and Z is a molecule having the general formula -OR (f-a) -T group, where R (f-a) is a fluoropolyoxyalkylene chain containing from 0 to 10 repeating units, the repeating units being selected from the following: -CFXO-, -CF2CFXO-, -CF2CF2CF2O-, -CF2CF2CF2CF2O-, wherein each X is independently F or CF3 and T is a C1-C3 perfluoroalkyl group; R pf-F is a chain with the following formula: -OD F -(CFX # ) z1 -O(R f )(CFX ＊ ) z2 -D F ＊ - in z1, z2, X # , X ＊ and (R f ) is as defined above; D F and D F ＊ , which are the same or different from each other, are perfluorinated alkylene chains containing from 1 to 6 carbon atoms, said alkyl chain being optionally substituted with at least one perfluorinated alkyl group containing from 1 to 3 carbon atoms.

42. The polymer according to claim 41 (PFPE OHOH ), the polymer having a number average molecular weight (Mn) from 7,000 Daltons and up to 30,000 Daltons, according to 19 F-NMR measurement; and / or a functionality F of at least 1.80 HFPE-P .

43. The polymer according to claim 41 (PFPE OHOH ), where D F ＊ is a perfluorinated alkylene chain containing from 1 to 3 carbon atoms.

44. The polymer according to claim 41 (PFPE OHOH ), where R CF is a perfluoroalkyl chain containing from 2 to 6 carbon atoms, optionally interrupted by one or more oxygen atoms.

45. The polymer according to claim 41 (PFPE OHOH ), where (R f ) consists of repeating units R°.

46. ​​The polymer according to claim 41 (PFPE OHOH ), where D F and D F ＊ , which are the same or different from each other, are perfluorinated alkylene chains containing from 1 to 3 carbon atoms.

47. The polymer according to claim 42 (PFPE OHOH ), wherein the polymer has a number average molecular weight (Mn) from 9,000 Daltons and up to 30,000 Daltons.

48. The polymer according to claim 42 (PFPE OHOH ), wherein the polymer has a functionality F of at least 1.85 HFPE-P .

49. The polymer according to claim 42 (PFPE OHOH ), wherein the polymer has a number average molecular weight (Mn) of from 9,000 Daltons and up to 20,000 Daltons and / or a functionality F of at least 1.80 HFPE-P .

50. A method for synthesizing a polymer (PFPE) according to claim 41 OHOH ) method [method (P OHOH )], the method (P OHOH )include: (V) providing a polymer (PFPE) according to any one of claims 1 to 11 EST ), (VI) making the polymer (PFPE EST ) is contacted with at least one reducing agent so as to make the polymer (PFPE EST ) chain ends are hydrolyzed to -CH2OH groups, thereby providing the polymer (PFPE OHOH ).