Process for producing an aqueous dispersion containing particles of a fluorinated polymer (F)

Abstract

The present invention relates to a method for producing an aqueous dispersion containing particles of a fluorinated polymer (F) comprising repeating units derived from at least C2-C3 hydrofluoroolefin (HFO), the method comprising free radical polymerization of at least one C2-C3 hydrofluoroolefin (HFO) in an aqueous medium in the presence of at least one partially fluorinated surfactant (S), and relates to the latex obtained by said method.

Description

Technical Field

[0001] This application claims priority based on European Patent Application No. 22180673.0 filed on June 23, 2022, and the entire content of this application is incorporated herein by reference for all purposes.

[0002] The present invention relates to a method for producing an aqueous dispersion containing particles of a fluorinated polymer (F) using at least one partially fluorinated surfactant (S), and to a latex obtained by such a method.

[0003] Known methods for preparing fluorinated polymers are aqueous polymerizations involving fluorinated surfactants. As an example, such methods are described in International Publication No. WO 2018 / 189091 and International Publication No. WO 2018 / 189092 of Solvay Speciality Polymers Italy S.p.a.

[0004] As is well known, the use of certain fluorinated surfactants is sometimes restricted for environmental reasons because they are not biodegradable within an acceptable time period or range of conditions. Therefore, there is a continuing need for novel surfactants that are suitable for preparing fluorinated polymers by aqueous polymerization processes, with or without a nucleating agent, and that have improved biodegradability.

[0005] Non-fluorinated surfactants such as alkyl phosphates, alkyl sulfonates, alkyl sulfates, or alkyl carboxylates usually are not suitable for use in the aqueous free-radical polymerization of fluorinated or partially fluorinated monomers because they have H atoms that can be abstracted by free-radical species during the polymerization process. These transfer reactions result in a lower molecular weight of the fluorinated polymer and, as a result, impaired properties.

[0006] Therefore, there is a need for a novel surfactant that is suitable for producing fluorinated polymers by an aqueous free radical polymerization process regardless of the presence of a nucleating agent, causes only limited transfer reactions, and has excellent stability of the resulting aqueous dispersion of the fluorinated polymer.

[0007] Surprisingly, it has been found that the partially fluorinated surfactant according to the present invention has a high degree of degradability while being suitable for producing an aqueous dispersion containing particles of a fluorinated polymer by an aqueous free radical polymerization process.

[0008] The present invention relates to a method for producing an aqueous dispersion containing particles of a fluorinated polymer (F) comprising repeating units derived from at least C2-C3 hydrofluoroolefins (HFOs), said method comprising, in the presence of at least one partially fluorinated surfactant (S) selected from the group consisting of compounds of formula (I): R-CFX-P (I), formula (II): P-CFX-(CH2) n -CFX-P (II), formula (III): R-CF(-P)2, free radical polymerizing at least one C2-C3 hydrofluoroolefin (HFO) in an aqueous medium, wherein in formulas (I)-(III), · R is an optionally branched C3-C 16 alkyl or alkenyl chain, which may optionally contain one or more catena heteroatoms selected from N, O, and S, may optionally contain a carbonyl group, may optionally contain one or more halogen atoms selected from Cl, Br, and I, and may optionally contain a C3-C8 aliphatic ring, · n is an integer from 2 to 16, · -P represents -COO-M, -SO3-M, or -PO3-M, where M is H, or an alkali metal, or an ammonium group N(R')4, and R' is the same or different in each occurrence and is a hydrogen atom or a C1-C6 hydrocarbon group, preferably an alkyl group, · X is H or F.

[0009] Typically, the surfactant (S) corresponds to formula (I): R-CFX-P (I), formula (II): P-CFX-(CH2) n -CFX-P (II), or formula (III): R-CF(-P)2. In formulas (I) to (III), ·R is an optionally branched C3-C 16 alkyl or alkenyl chain, which may optionally contain one or more chain heteroatoms selected from N, O, and S, may optionally contain a carbonyl group, may optionally contain one or more halogen atoms selected from Cl, Br, and I, and may optionally contain a C3-C8 aliphatic ring, ·n is an integer from 2 to 16, ·-P represents -COO-M, -SO3-M, or -PO3-M, where M is H, or an alkali metal, or an ammonium group N(R’)4, and R’ is the same or different in each occurrence, and is a hydrogen atom or a C1-C6 hydrocarbon group, preferably an alkyl group, ·X is H or F.

[0010] In some embodiments, M is an ammonium group, more preferably an NH4 group.

[0011] In some preferred embodiments, -P represents -COO-M, and in more preferred embodiments, -P represents -COO-NH4.

[0012] In some embodiments, R is a straight-chain C3-C 16 fully hydrogenated alkyl chain.

[0013] In some other embodiments, R is an optionally branched C3-C 16 alkyl or alkenyl chain containing a carbonyl group.

[0014] In still some other embodiments, R is an optionally branched C3-C 16An alkyl or alkenyl chain, for example, R contains one or more ether groups, or R contains one or more thioether groups, or R contains one or more amine groups.

[0015] In some embodiments, R is an optionally branched C3 - C containing a chain N atom and a carbonyl group. 16 An alkyl or alkenyl chain, for example, R contains an amide group.

[0016] In some other embodiments, R is an optionally branched C3 - C containing a chain O atom and a carbonyl group. 16 An alkyl or alkenyl chain, for example, R contains an ester group.

[0017] In still some other embodiments, R is an optionally branched C3 - C containing one or more halogen atoms selected from Cl, Br, and I. 16 An alkyl or alkenyl chain.

[0018] In some embodiments, R is an optionally branched C3 - C containing a C3 - C8 aliphatic ring, for example, a C6 aliphatic ring. 16 An alkyl or alkenyl chain. In some embodiments, the surfactant (S) is selected from the group consisting of R - CFH - COO - NH4, 4HN - OOC - CFH - (CH2) n - CFH - COO - NH4, and R - CFH - (COO - NH4)2, where R and n in these formulas are as described above.

[0019] Good results were obtained when the surfactant (S) was CH3(CH2)7CFHCOO - NH4.

[0020] In some embodiments, the surfactant (S) is selected from the group consisting of R - CFH - COO - NH4 and R - CFH - (COO - NH4)2, where in these formulas, R is as described above and R contains a carbonyl group.

[0021] In some preferred embodiments, the surfactant (S) is CH3-CO-(CH2)7CFHCOO-NH4.

[0022] As an example, the surfactant (S) according to the present invention can be synthesized according to the following reaction scheme: [Chemical formula] (wherein X is H or F, R0’ is a C1-C3 hydrogenated alkyl chain, preferably an ethyl group, and R0 is an optionally branched hydrogenated alkyl chain of C1-C 14 which may optionally contain a carbonyl group).

[0023] ICFXCOOR0’ can be prepared from the bromide or chloride analog BrCFXCOOR0’ or ClCFXCOOR0’ according to the reaction pathways described in Journal American Chemical Society, 2001, vol. 123, no. 30, pages 7207-7219 or Journal of Chemical Society, Perkin Trans. 1, 1996, 1741-47.

[0024] The addition of the iodinated derivative to the unsaturated compound represented in step 1) of reaction (i) can be carried out using Fe in tetrahydrofuran as described in Journal of Chemical Society, Perkin Trans. 1, 1996, 1741-47. Other methods involving the use of sodium dithionite Na2S2O4 as described, for example, in Journal of Fluorine Chemistry, 2005, 126, pages 63-67 may also be used. Examples of syntheses involving unsaturated compounds containing electron-withdrawing groups such as carbonyl groups can be found in Journal of Chemical Society, Perkin Trans. 1, 1996, 1741-47.

[0025] The further reduction with Zn in acetic acid as represented in step 2) of (i) is described in Journal of Chemical Society, Perkin Trans. 1, 1996, 1741 - 47 or Journal of Fluorine Chemistry, 1992, vol. 59, pages 9 - 14.

[0026] The recovery of carboxylic acids from alkyl esters, such as ethyl esters, represented by (ii) is described, for example, in Tetrahedron, 1994, vol. 50, n°33, pages 9847 - 9864.

[0027] The preparation of ammonium salts of carboxylic acids as described in (iii) is well - known to those skilled in the art.

[0028] Other methods can also be used to prepare the surfactant (S). By way of example, but not limitation, the route for the preparation of intermediate ethyl esters of the formula R - CH2CH2CFXCOOEt without the use of ICFXCOOEt can be found in Tetrahedron, 1994, vol. 50, n°33, pages 9847 - 9864.

[0029] The biodegradability of the surfactant (S) was evaluated according to the carbon dioxide (CO2) evolution test (reference TG301B) described in the "OECD Guideline for testing of chemicals No. 301 B" of the OECD (Organisation for Economic Co - operation and Development): https: / / read.oecd - ilibrary.org / environment / test - no - 301 - ready - biodegradability_9789264070349 - en#page18.

[0030] According to this method, activated sludge is inoculated into a solution of the test substance in a mineral medium and cultured under aerobic conditions. Then, biodegradation is determined by measuring the actual amount of CO2 produced compared to the theoretical amount of CO2 that would be produced if the test compound were completely mineralized. CO2 measurements are made at a frequency that can distinguish the start and end of biodegradation.

[0031] A reference compound known to be biodegradable is carried out in parallel to confirm the validity of the procedure. The average value of biodegradation is calculated based on the results obtained from four replicates.

[0032] It complies with "Guidelines for the testing of chemicals.Revised introduction to the OECD guidelines for testing of chemicals,Section 3,Part 1,Chapter 2.3(Adopted march 23,2006)".

[0033] A single-component chemical substance is judged to be readily biodegradable if it meets the following two conditions: 1) At least 60% biodegradation results are obtained within 28 days; 2) Reach the pass level within 10 days after 10% biodegradation is achieved (10-day window).

[0034] For chemical substances that show at least 60% biodegradation results within 28 days but fail to meet the criteria of the 10-day window, it is concluded that they are not readily biodegradable, but they are still considered to be essentially biodegradable. That is, it is expected to be completely mineralized in the environment.

[0035] For substances that do not reach 60% biodegradation within 28 days, it is expected that the test period can be extended by up to 60 days by an extended ready biodegradability test (see ECHA Guidance on Information Requirements and Chemical Safety Assessment Chapter R.7b: Endpoint specific guidance Version 4.0 (June 2017) and ECHA Guidance on Information Requirements and Chemical Safety Assessment - Chapter R.11: PBT / vPvB assessment version 3.0, June 2017). Results of at least 60% biodegradability within 60 days are part of the evidence that the test item is not persistent. Substances for which results of at least 60% biodegradation are not obtained within 60 days may be persistent and further evaluation is required to conclude persistence.

[0036] Typically, the partially fluorinated surfactants according to the present invention meet the pass level criterion of at least 60% biodegradability, which supports that they are not persistent.

[0037] Surprisingly, the partially fluorinated surfactants according to the present invention having -CHF- groups meet the above two criteria, namely at least 60% biodegradability within 28 days and the criterion of a 10-day window.

[0038] Furthermore, it has been found that the partially fluorinated surfactant (S) according to the present invention is suitable for use in a process for producing an aqueous dispersion containing particles of a fluorinated polymer (F) comprising repeating units derived from at least C2 - C3 hydrofluoroolefins (HFO). The process comprises free radical polymerization of at least one C2 - C3 hydrofluoroolefin (HFO) in an aqueous medium.

[0039] Although not restricted by any theory, the F atom on the α-carbon of the polar acidic group salt of the surfactant (S) according to the present invention tends to suppress the transfer reaction during the free radical polymerization of the fluorinated monomer on the one hand, and on the other hand, it seems to enable the surfactant (S) to stabilize the aqueous dispersion of the fluorinated polymer (F).

[0040] One or more surfactants (S) defined above can be added to the aqueous free radical polymerization medium of the method of the present invention, preferably in a total amount in the range of 0.001% by weight to 20% by weight based on the weight of the aqueous polymerization medium.

[0041] Usually, the fluorinated polymer (F) contains repeating units derived from at least C2-C3 hydrofluoroolefin (HFO), and is obtained by free radical polymerization of at least one C2-C3 hydrofluoroolefin (HFO) in an aqueous medium.

[0042] The C2-C3 hydrofluoroolefin (HFO) according to the present invention is usually selected from the group consisting of vinylidene fluoride (VDF), fluoroethylene, cis-1,2-difluoroethylene, trans-1,2-difluoroethylene, trifluoroethylene, 2,3,3,3-tetrafluoropropylene, cis-1,3,3,3-tetrafluoropropylene, trans-1,3,3,3-tetrafluoropropylene, cis-1,2,3,3-tetrafluoropropylene, trans-1,2,3,3-tetrafluoropropylene, 1,1,3,3-tetrafluoropropylene, 1,1,2,3-tetrafluoropropylene, cis-1,2,3,3,3-pentafluoropropylene, trans-1,2,3,3,3-pentafluoropropylene, 1,1,3,3,3-pentafluoropropylene, 1,1,2,3,3-pentafluoropropylene, 3,3,3-trifluoropropylene, 2,3,3-trifluoropropylene, cis-1,3,3-trifluoropropylene, trans-1,3,3-trifluoropropylene, cis-1,2,3-trifluoropropylene, trans-1,2,3-trifluoropropylene, 1,1,3-trifluoropropylene, 1,1,2-trifluoropropylene, and mixtures thereof.

[0043] Preferably, the C2-C3 hydrofluoroolefin (HFO) is vinylidene fluoride (VDF) or 2,3,3,3-tetrafluoropropylene, preferably vinylidene fluoride (VDF).

[0044] In some embodiments, the fluorinated polymer (F) consists essentially of repeating units derived from vinylidene fluoride (VDF).

[0045] In some other embodiments, the fluorinated polymer (F) further comprises repeating units derived from at least one additional fluorinated monomer, and is thus obtained by free radical polymerization in an aqueous medium of at least one C2-C3 hydrofluoroolefin (HFO) and said at least one additional fluorinated monomer.

[0046] The additional fluorinated monomer means an ethylenically unsaturated monomer containing at least one fluorine atom. The selection of this additional fluorinated monomer is not particularly limited, and any fluorinated monomer can be used.

[0047] The additional fluorinated monomer may further contain one or more other halogen atoms (Cl, Br, I) and may be partially or fully halogenated.

[0048] Non-limiting examples of the additional (per)fluorinated monomer include · C2-C8 perfluoroolefins such as tetrafluoroethylene (TFE) or hexafluoropropylene (HFP); · C2-C8 hydrogenated fluoroolefins such as vinyl fluoride, 1,2-difluoroethylene, trifluoroethylene (TrFE), hexafluoroisobutene (HFIB); · Perfluoroalkyl ethylene of the formula CH2=CH-Rf0 (wherein Rf0 is a C1-C6 perfluoroalkyl group); · Chloro- and / or bromo- and / or iodo-C2-C6 fluoroolefins such as chlorofluoroethylene (CFE) or chlorotrifluoroethylene (CTFE); · Perfluoroalkyl vinyl ether (PAVE) of the formula CF2=CF-O-Rf1 (wherein Rf1 is a C1-C6 perfluoroalkyl group, for example CF3, C2F5, C3F7); · Partially fluorinated alkyl vinyl ether of the formula CF2=CF-O-Rf2 (wherein Rf2 is a C1-C6 partially fluorinated alkyl group); · Perfluoroalkoxyalkyl vinyl ether (PAAVE) of the formula CF2=CF-O-X0 (wherein X0 is a C1-C 12 perfluoroalkoxyalkyl group); · Partially fluorinated alkoxyalkyl vinyl ether of the formula CF2=CF-O-X1 (wherein X1 is a C1-C 12 partially fluorinated alkoxyalkyl group); · Partially fluorinated fluoroalkoxyalkyl vinyl ethers of the formula CF2=CF-O-X2 (wherein X2 is a C1-C 12 12 alkoxyalkyl group); · Hydrofluoroalkyl vinyl ethers according to the formula CH2=CF-O-Y (wherein Y is a C1-C6 fluoro or perfluoroalkyl, for example -CF3, -C2F5, -C3F7); · Fluorodioxoles, preferably perfluorodioxoles; · Formula: CFZ=Cz-O-CF2-O-Rf3 (wherein Rf3 is selected from linear or branched C1-C6 (per)fluoroalkyl; C5-C6 cyclic (per)fluoroalkyl; and linear or branched C2-C6 (per)fluorooxyalkyl containing 1 to 3 chain oxygen atoms, Z = F, H; preferably, Z is F and Rf3 is -CF2CF3 (MOVE1); -CF2CF2OCF3 (MOVE2); or -CF3 (MOVE3)) having (per)fluoro-methoxy-vinyl ether (hereinafter, MOVE); are exemplified.

[0049] In some preferred embodiments, the fluorinated polymer (F) further comprises repeating units derived from at least one monomer selected from the group consisting of cis-1,2-difluoroethylene, trans-1,2-difluoroethylene, trifluoroethylene (TrFE), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), chlorofluoroethylene (CFE), chlorotrifluoroethylene (CTFE), and perfluoroalkyl vinyl ether (PAVE) of the formula CF2=CF-O-Rf1 (wherein Rf1 is a C1-C6 perfluoroalkyl group).

[0050] Perfluoroalkyl vinyl ether (PAVE) is preferably selected from the group consisting of perfluoromethyl vinyl ether (PMVE) of the formula CF2=CF-O-CF3, perfluoroethyl vinyl ether (PEVE) of the formula CF2=CF-O-CF2-CF3, and perfluoropropyl vinyl ether (PPVE) of the formula CF2=CF-O-CF2-CF2-CF3. Also, mixtures of different PAVEs can be used herein.

[0051] In some embodiments, the fluorinated polymer (F) is · VDF and TFE; · VDF, TFE, and CTFE; · VDF, TFE, and PAVE; · VDF, TFE, and HFP; · VDF, TFE, HFP, and PAVE; · VDF and TrFE; · VDF, TrFE, and CFE; · VDF, TrFE, and CTFE; · VDF, TrFE, and HFP; · VDF and CFE; · VDF and CTFE; · VDF and HFP; · VDF, HFP, and PAVE; or · VDF, HFP, and CTFE; contains repeating units derived from, preferably consisting essentially of, more preferably consisting of these.

[0052] In some embodiments, the fluorinated polymer (F) is (in mol% based on the total number of moles of repeating units) · 5 mol% to 95 mol% of repeating units derived from vinylidene fluoride (VDF), and · 5 mol% to 95 mol% of repeating units derived from at least one additional fluorinated monomer, and contains, preferably consisting essentially of, more preferably consisting of these.

[0053] In some other embodiments, the fluorinated polymer (F) is · 15 mol% to 35 mol% of repeating units derived from vinylidene fluoride (VDF), and · 65 mol% to 85 mol% of repeating units derived from at least one ethylenically unsaturated fluorinated monomer, and comprises, preferably consists essentially of, and more preferably consists of these.

[0054] In some further alternative embodiments, the fluorinated polymer (F) is · 60 mol% to 90 mol% of repeating units derived from vinylidene fluoride (VDF), and · 10 mol% to 40 mol% of repeating units derived from at least one ethylenically unsaturated fluorinated monomer, and comprises, preferably consists essentially of, and more preferably consists of these.

[0055] In some embodiments, the fluorinated polymer (F) is · 60 mol% to 80 mol% of repeating units derived from vinylidene fluoride (VDF), and · 15 mol% to 25 mol% of repeating units derived from hexafluoropropylene (HFP), and · 5 mol% to 15 mol% of repeating units derived from tetrafluoroethylene (TFE), and comprises, preferably consists essentially of, and more preferably consists of these.

[0056] Good results were obtained with a fluorinated polymer (F) consisting of · 70 mol% of repeating units derived from vinylidene fluoride (VDF), and · 19 mol% of repeating units derived from hexafluoropropylene (HFP), and · 11 mol% of repeating units derived from tetrafluoroethylene (TFE). Optionally, the fluorinated polymer (F) of the present invention has the general formula as described, for example, in European Patent No. 661304 A:

[0057] ​ [Chemical formula] (wherein R1, R2, R3, R4, R5, and R6 are the same as or different from each other and are H or C1-C5 alkyl; Z may optionally contain an oxygen atom and is preferably a linear or branched C1-C 18 hydrocarbon radical (including an alkylene or cycloalkylene radical), or a repeating unit derived from a bis-olefin [bis-olefin (OF)] having a (per)fluoropolyoxyalkylene radical).

[0058] The bis-olefin (OF) is preferably of the formulas (OF-1), (OF-2), and (OF-3): (OF-1) [Chemical formula] (wherein j is an integer from 2 to 10, preferably from 4 to 8, and R1, R2, R3, R4 are the same as or different from each other and are H, F or C 1~5 alkyl or (per)fluoroalkyl group); (OF-2) [Chemical formula] (wherein each of A is the same as or different from each other and in each occurrence and is independently selected from F, Cl and H, and each of B is the same as or different from each other and in each occurrence and is independently selected from F, Cl, H and OR B is independently selected from, R B is a branched or linear alkyl radical which may be partially, substantially or completely fluorinated or chlorinated, and E is a divalent group having 2 to 10 carbon atoms in which an ether bond may be inserted and which may optionally be fluorinated, and preferably E is a -(CF2) m - group where m is an integer from 3 to 5, and a preferred bis-olefin of the (OF-2) type is F2C=CF-O-(CF2)5-O-CF=CF2); (OF-3) [Chemical formula] (wherein E, A and B have the same meanings as defined above; R5, R6, and R7 are the same as or different from each other, and are H, F, or C 1~5 alkyl or (per)fluoroalkyl group) selected from the group consisting of those conforming to

[0059] Good results were obtained with the (OF-1)-type bis-olefin of the formula H2C=CH-(CF2)6-CH=CH2.

[0060] In some other embodiments, the fluorinated polymer (F) comprises, preferably consists essentially of, more preferably consists of, the following monomer composition (mol% based on the total number of moles of repeating units): (i) Vinylidene fluoride (VDF) 35 - 85%, hexafluoropropene (HFP) 10 - 45%, tetrafluoroethylene (TFE) 0 - 30%, (per)fluoroalkyl vinyl ether (PAVE) 0 - 15%, bis-olefin (OF): 0 - 5%; (ii) Vinylidene fluoride (VDF) 50 - 80%, (per)fluoroalkyl vinyl ether (PAVE) 5 - 50%, tetrafluoroethylene (TFE) 0 - 20%, bis-olefin (OF): 0 - 5%; (iii) Vinylidene fluoride (VDF) 20 - 30%, C2 - C8 non-fluorinated olefin (Ol) 10 - 30%, hexafluoropropene (HFP) and / or (per)fluoroalkyl vinyl ether (PAVE) 18 - 27%, tetrafluoroethylene (TFE) 10 - 30%, bis-olefin (OF): 0 - 5%; (iv) Tetrafluoroethylene (TFE) 45 - 65%, C2 - C8 non-fluorinated olefin (Ol) 20 - 55%, vinylidene fluoride 5 - 30%, bis-olefin (OF): 0 - 5%; (v) 33 to 75% tetrafluoroethylene (TFE), 15 to 45% (per)fluoroalkyl vinyl ether (PAVE), 5 to 30% vinylidene fluoride (VDF), 0 to 30% hexafluoropropene HFP, 0 to 5% bis-olefin (OF); (vi) 35 to 85% vinylidene fluoride (VDF), 5 to 40% (per)fluoro-methoxy-vinyl ether (MOVE), 0 to 30% (per)fluoroalkyl vinyl ether (PAVE), 0 to 40% tetrafluoroethylene (TFE), 0 to 30% hexafluoropropene (HFP), 0 to 5% bis-olefin (OF).

[0061] Optionally, the fluorinated polymer (F) of the present invention also contains iodine and / or bromine curing sites.

[0062] These iodine and / or bromine curing sites may be included as pendant groups attached to the main chain of the fluorinated polymer (F) chain, or may be included as end groups of the polymer chain.

[0063] According to the first embodiment, the iodine and / or bromine curing sites are included as pendant groups attached to the main chain of the fluorinated polymer (F) chain; the fluorinated polymer (F) chain according to this embodiment typically · Bromo and / or iodo alpha-olefins containing 2 to 10 carbon atoms, such as bromotrifluoroethylene or bromotetrafluorobutene described in, for example, US Patent No. 4,035,565 (DU PONT) 12 / 07 / 1977, or other compounds disclosed in US Patent No. 4,694,045 (DU PONT) 15 / 09 / 1987, such as bromo and / or iodo alpha-olefins; · Iodo and / or bromofluoroalkyl vinyl ethers (especially those described in the patents of US Patent No. 4,546,62, US Patent No. 4,564,662 (MINNESOTA MINING) 14 / 01 / 1986 and European Patent Application Publication No. 199,138A (DAIKIN IND LTD) 29 / 10 / 1986) It contains repeating units derived from brominated and / or iodinated curing site comonomers selected from

[0064] According to a second embodiment, the iodine and / or bromine curing site (preferably iodine curing site) is included as a terminal group of the fluorinated polymer (F) chain; the fluorinated polymer according to this embodiment is usually added to the polymerization medium during the production of the fluorinated polymer (F), · An iodinated and / or brominated chain transfer agent (suitable chain transfer agents are typically of the formula Rf4(I) x (Br) y wherein Rf4 is a (per)fluoroalkyl or (per)fluorochloroalkyl containing 1 to 8 carbon atoms, and x and y are integers from 0 to 2 with 1≦x + y≦2 (see, for example, US Patent No. 4243770 (DAIKIN IND LTD) 6 / 01 / 1981 and US Patent No. 4943622 (Nippon Mektron Ltd.) 24 / 07 / 1990)); and · An alkali metal or alkaline earth metal iodide and / or bromide, such as those described in US Patent No. 5173553 (AUSIMONT SRL) 22 / 12 / 1992, among others; is obtained by adding at least one of

[0065] Advantageously, in order to ensure acceptable reactivity, it is generally understood that the content of iodine and / or bromine in the fluorinated polymer (F) should be at least 0.05% by weight, preferably at least 0.06% by weight, based on the total weight of the fluorinated polymer (F).

[0066] On the other hand, an amount of iodine and / or bromine that is preferably not more than 7% by weight, more specifically not more than 5% by weight, and further not more than 4% by weight, based on the total weight of the fluorinated polymer (F), is generally selected to avoid side reactions and / or adverse effects on thermal stability.

[0067] Generally, the amount of iodine in the fluorinated polymer (F) ranges from 0.05% to 7% by weight, preferably from 0.10% to 4.0% by weight, based on the total weight of the fluorinated polymer (F).

[0068] In some preferred embodiments, the iodinated chain transfer agent is of the formula I-(CF2) k -I, where k is an integer from 2 to 10 in the formula.

[0069] Good results were obtained with I-(CF2)4-I as the iodinated chain transfer agent.

[0070] In some embodiments, the fluorinated polymer (F) of the present invention comprises repeating units derived from the aforementioned bis-olefin [bis-olefin (OF)] and iodine atoms as end groups.

[0071] Good results were obtained using H2C=CH-(CF2)6-CH=CH2, a (OF-1) type bis-olefin, and I-(CF2)4-I as the iodinated chain transfer agent.

[0072] In some embodiments, a method comprising free radical polymerization of at least one C2-C3 hydrofluoroolefin (HFO) in an aqueous medium in the presence of at least one surfactant (S) according to the present invention is carried out in the presence of at least one non-functional perfluoropolyether (PFPE).

[0073] Any non-functional perfluoropolyether composed of an array of perfluorooxyalkylene units can be advantageously utilized. Generally suitable perfluoropolyethers have neutral end groups and an average molecular weight in the range of 300 to 3000. Suitable non-functional perfluoropolyethers correspond, for example, to the following formulas: i) R where the perfluoro-oxyalkylene units are randomly distributed g O(CF(CF3)-CF2O) q (CFO(CF3)) r (CF2O) s Rg ’; or ii) R g ”O(CF2CF2O) q (CFO(CF3)) r (CF2O) s R g ’” (wherein R g and R g ’, each R g ” and R g ’” are the same as or different from each other, and are -CF3, -C2F5, -C3F7, and q, r, s, each q’, r’, s’ have values that satisfy the above conditions regarding the average molecular weight).

[0074] For the formula CF3O(CF2 - CF(CF3)O) o (CF2O) p CF3 (wherein o / p = 20), good results were obtained using Galden (registered trademark) D02 available from Solvay with an average molecular weight of 450.

[0075] In some embodiments, a method comprising free-radical polymerizing at least one C2 - C3 hydrofluoroolefin (HFO) in an aqueous medium in the presence of at least one surfactant (S) according to the present invention is carried out in the presence of at least one nucleating agent. A nucleating agent means any agent suitable for promoting the formation of latex particles and enabling the obtaining of a fluorinated polymer having a primary particle size smaller than that obtained when polymerizing without said nucleating agent. Nucleating agents are well known to those skilled in the art. By way of example, nucleating agents include perfluoropolyether (PFPE) acids or their salts, and nonionic surfactants, such as nonionic hydrocarbon surfactants. For the hexafluoropropylene oxide oligomer having a carboxylic acid group corresponding to the formula C3F7O[CF(CF3)CF2O] t CF(CF3)COOH (wherein t is a number such that the average molecular weight Mw of the oligomer is in the range of 1000 Da to 1500 Da, preferably 1100 Da to 1400 Da), good results were obtained when used as a nucleating agent.

[0076] Depending on the chemical properties of the nucleating agent, the nucleating agent is usually used in an amount of 1000 ppm or less, preferably 500 ppm or less, more preferably 100 ppm or less, and in some cases 10 ppm or less, based on the aqueous medium. Good results were obtained with a hexafluoropropylene oxide oligomer having a carboxylic acid group in an amount of 100 ppm or less based on the aqueous medium.

[0077] Galden® D02 available from Solvay and the formula C3F7O[CF(CF3)CF2O] defined above t Good results were obtained by using a hexafluoropropylene oxide oligomer having a carboxylic acid group corresponding to CF(CF3)COOH as a nucleating agent.

[0078] Free radical polymerization in an aqueous medium is typically carried out at a pressure of 10 bar to 40 bar, preferably 11 bar to 25 bar.

[0079] The polymerization temperature usually depends particularly on the nature of the radical initiator used to initiate the free radical polymerization. Aqueous free radical polymerization is typically carried out at a temperature included in 50 °C to 135 °C, preferably 55 °C to 130 °C.

[0080] The choice of radical initiator is not particularly limited, but it should be understood that since the reaction is carried out in an aqueous medium, a water-soluble radical initiator is preferred to initiate and / or accelerate the polymerization. Nevertheless, initiators that are insoluble or poorly soluble in water can also be used in the present invention.

[0081] Both organic radical initiators and inorganic radical initiators can be used in the process of the present invention. Suitable inorganic radical initiators include, but are not limited to, persulfates such as sodium, potassium and ammonium persulfates and hydrogen peroxide.

[0082] In addition, organic radical initiators may be used, and examples thereof include: acetylcyclohexanesulfonyl peroxide; diacetyl peroxydicarbonate; dialkyl peroxydicarbonates such as diethyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate; tert-butyl perneodecanoate; 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile); tert-butyl perpivalate; dioctanoyl peroxide; dilauroyl peroxide; 2,2'-azobis(2,4-dimethylvaleronitrile); tert-butylazo-2-cyanobutane; dibenzoyl peroxide; tert-butyl per-2-ethylhexanoate; tert-butyl permaleate; 2,2'-azobis(isobutyronitrile); bis(tert-butylperoxy)cyclohexane; tert-butyl peroxyisopropyl carbonate; tert-butyl peracetate; 2,2'-bis(tert-butylperoxy)butane; dicumyl peroxide; di-tert-amyl peroxide; di-tert-butyl peroxide (DTBP); p-methane hydroperoxide; pinane hydroperoxide; cumene hydroperoxide; and tert-butyl hydroperoxide.

[0083] Other suitable radical initiators include, in particular, halogenated free radical initiators such as chlorocarbon-based and fluorocarbon-based acyl peroxides, for example trichloroacetyl peroxide, bis(perfluoro-2-propoxypropionyl) peroxide, [CF3CF2CF2OCF(CF3)COO]2, perfluoropropionyl peroxide, (CF3CF2CF2COO)2, (CF3CF2COO)2, {(CF3CF2CF2)[CF(CF3)CF2O] m CF(CF3)COO}2 (where m = 0 to 8), [ClCF2(CF2) n COO]2, and [HCF2(CF2) nCOO]2 (where n = 0 to 8); perfluoroalkyl azo compounds such as perfluoroazoisopropane, [(CF3)2CFN=]2, R*N=NR* (where R* is a linear or branched perfluorocarbon group having 1 to 8 carbons); stable or hindered perfluoroalkane radicals such as hexafluoropropylene trimer radical, [(CF3)2CF]2(CF2CF2)C ● Examples include radicals and perfluoroalkanes.

[0084] Redox systems containing at least two components that form a redox pair, such as oxalate - permanganate, dimethylaniline - benzoyl peroxide, diethylaniline - benzoyl peroxide, and diphenylamine - benzoyl peroxide, may also be used as radical initiators in the present invention.

[0085] Among inorganic radical initiators, inorganic persulfates and especially potassium and / or ammonium persulfates are particularly preferred. Good results were obtained with ammonium persulfate (APS).

[0086] Among organic radical initiators, peroxides having a self - accelerating decomposition temperature (SADT) higher than 50 °C are particularly preferred, for example: di - tert - butyl peroxide (DTBP), ditert - butyl peroxydiisopropyl carbonate, tert - butyl (2 - ethyl - hexyl) peroxydicarbonate, tert - butyl peroxy - 3,5,5 - trimethylhexanoate, etc.

[0087] One or more of the radical initiators defined above can advantageously be added to the aqueous polymerization medium of the process of the present invention in a total amount in the range of 0.001 wt% to 20 wt% based on the weight of the aqueous polymerization medium.

[0088] Typically, a small amount of initiator is introduced into the reactor to initiate the polymerization process at the start, and then additional amounts of initiator are added continuously or in stages to the reactor until the polymerization reaction is complete.

[0089] In some embodiments, the aqueous dispersion comprising particles of fluorinated polymer (F) comprising repeat units derived from at least one C2-C3 hydrofluoroolefin (HFO) obtained by the process according to the invention is in the form of an aqueous latex obtained by aqueous emulsion polymerization.

[0090] The present invention therefore also relates to an aqueous latex obtainable by the process according to the invention as described above.

[0091] The present invention also relates to an aqueous latex comprising at least one fluorinated polymer (F) as described above and at least one partially fluorinated surfactant selected from the group consisting of compounds of formula (I), formula (II), and formula (III).

[0092] Usually, the aqueous latex obtained by the method according to the present invention contains 10% by weight to 30% by weight of the above-mentioned fluorinated polymer (F) based on the total weight of the aqueous latex.

[0093] Typically, the aqueous latex obtained by the process according to the invention comprises the fluorinated polymer (F) in the form of primary particles having an average primary particle size of 50 to 350 nm, measured according to ISO 22412 (2017).

[0094] "Average primary particle size" means the average particle size of the primary particles of the fluoropolymer (F) obtained by aqueous emulsion polymerization.

[0095] For the purposes of the present invention, the "primary particles" of the fluorinated polymer (F) are intended to be distinguishable from aggregates of the primary particles. An aqueous latex containing the primary particles of the fluorinated polymer (F) can advantageously be obtained by the process according to the invention, which comprises an aqueous emulsion polymerization. Aggregates of the primary particles of the fluorinated polymer (F) are typically obtained by recovery and conditioning steps in the production of the fluorinated polymer (F), such as concentration and / or coagulation of the aqueous fluorinated polymer (F) latex and subsequent drying and homogenization, whereby a fluorinated polymer (F) powder is obtained.

[0096] As described above, the fluorinated polymer (F) of the present invention, in some embodiments, contains iodine and / or bromine curing sites in an amount typically in the range of from 0.05% to 7% by weight, preferably from 0.10% to 4.0% by weight, based on the total weight of the fluorinated polymer (F). Such iodine-containing fluorinated polymers (F) can be cured in the presence of at least one peroxide (P) capable of generating radicals at a suitable rate at a relatively low temperature.

[0097] Accordingly, another object of the present invention is the use of the aqueous latex obtained by the process according to the invention in coating applications, such as dielectric coatings for capacitors or transistors.

[0098] Yet another object of the present invention is the use of the aqueous latex obtained by the process according to the invention in sealing or gasket applications, such as for automobiles.

[0099] If the disclosure of any patent, patent application, and publication incorporated herein by reference conflicts with the description of the present application to the extent that it may obscure a term, the description shall control.

Examples

[0100] Preparation of ICHFCOOEt (a) To a stirred solution of sodium iodide (0.29 mol, 1.2 eq) in dry acetone (240 cm3) was added ethyl bromofluoroacetate (0.24 mol, 1 eq) dropwise at room temperature over 1 h. After the addition was complete, the reaction mixture was stirred at room temperature overnight. The suspension was diluted with diethyl ether (150 cm3), filtered through a 0.45 μm PVDF membrane, and the residual solid was washed again with 2×25 cm 3 of diethyl ether. The filtered solution was evaporated under reduced pressure, and the remaining red oil was dissolved in 150 cm 3 of diethyl ether and washed with 150 cm 3 of semi-saturated aqueous Na2S2O3 solution. The organic phase was separated, washed again with deionized water, and then separated and dried over Na2SO4.

[0101] By distilling the organic phase under reduced pressure, 50 g of pure ethyl fluoroiodoacetate was obtained.

[0102] Ethyl fluoroiodoacetate (90%). Oil, 63 - 70 °C, 11 / 14 Torr.

[0103] Preparation of ethyl 2-fluorodecanoate (b) A heterogeneous mixture of iron powder (0.06 mol, 0.3 eq), 1-octene (0.78 mmol, 4 eq), ethyl fluoroiodoacetate (a) (45 g, 0.19 mol, 1 eq), and THF (490 cm 3 ) was stirred under nitrogen at 70 - 80 °C (bath temperature) for 15 h until the fluoroiodoacetate was completely converted. After cooling to room temperature, zinc (0.29 mol, 1.5 eq), ethanol (160 cm 3 ), and acetic acid (69 cm 3 ) were added with vigorous stirring, and the reaction was refluxed for an additional 2 h. The suspension was cooled, filtered through a Gauche D filter, and the solid residue was washed with 2×30 cm 3 of ethanol. The filtered solution was concentrated under reduced pressure to give a viscous pale yellow oil. This was extracted with 300 cm 3 of 10% NaHCO3 and 300 cm 3 of diethyl ether. The organic layer was separated, and the aqueous phase was extracted with 300 cm3 It was washed again with diethyl ether.

[0104] The combined organic layers were washed twice with 10% aqueous NaHCO3 solution and water, and then dried over Na2SO4. The solvent was removed under reduced pressure, and the target product (b) was isolated as a pale yellow oil in 70% yield.

[0105] Preparation of 2-fluorodecanoic acid (c) A solution of ethyl 2-fluorodecanoate (b) (25 g, 0.12 mol, 1 eq) in 1 M methanol was added dropwise to 150 cm of 1 M NaOH solution cooled to 0 °C. After the addition, the solution was stirred at room temperature for 2 hours. Methanol was removed under reduced pressure to obtain an aqueous dispersion of a white solid. This was filtered through a 0.45 μm PVDF membrane. The recovered white solid was washed with 2 × 100 cm of 3 distilled water and filtered again to obtain pure sodium 2-fluorodecanoate. The isolated white solid was treated with 1.2 eq of dilute HCl (11% in water) with stirring for 1 hour. Diethyl ether was added to the resulting mixture until the 2-fluorodecanoic acid was completely dissolved. After separation, the aqueous phase was extracted with 2 × 70 cm of 3 diethyl ether, and the recovered organic layer was dried over Na2SO4. The solvent was removed under reduced pressure to obtain a white crystalline solid. The overall yield was 94%, 3 and it was confirmed to be the target product (c) by 1H and 1 19F NMR. 19 It was confirmed to be the target product (c) by 1H and 19F NMR.

[0106] Preparation of ammonium 2-fluorodecanoate aqueous solution (d) 2-Fluorodecanoic acid (13 g, 0.068 mol, 1 eq) was placed at room temperature in a flask containing 24 g of water (35 wt% aqueous solution). The heterogeneous mixture was stirred vigorously. While monitoring the temperature and pH (pH = 7 - 8), ammonia solution (4.3 g, 0.075 mol, 1.1 eq, 33% by title) was added dropwise until the solid residue was completely dissolved. The complete conversion of the acid to the salt form and the concentration of the final solution were 1 confirmed by 1H NMR (35 wt%).

[0107] Coincident material · CH3(CH2)7CHFCOO-NH4 as a surfactant was prepared as described above. · C6O4 is a commercially available perfluorosurfactant composed of a mixture of diastereoisomers of ammonium 2,2-difluoro-2-{[2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1,3-dioxolan-4-yl]oxy}acetate used herein as a comparative surfactant. · The nucleating agent has an average molecular weight Mw of 1300 Da and is composed of an oligomer of hexafluoropropylene oxide having a carboxylic acid group corresponding to C3F7O[CF(CF3)CF2O] n CF(CF3)COOH. · The nucleating agent was introduced into the polymerization reactor simultaneously with the surfactant in the form of an aqueous solution containing the following respectively: · 30% by weight of CH3(CH2)7CHFCOO-NH4, 5% by weight of the nucleating agent and 65% by weight of water; or · 30% by weight of the ammonium salt of the perfluoro C6O4 surfactant, 15% by weight of the nucleating agent, and 55% by weight of water. · 1,4-Diiodoperfluorobutane (C4F8I2) as a mobile agent was introduced into the polymerization reactor in the form of a 15% by weight solution of Galden® D02. · The bisolefin of the formula H2C=CH-(CF2)6-CH=CH2 was introduced into the polymerization reactor in the form of a 33% by weight solution in Galden® D02. · Ammonium persulfate (APS) as an initiator was introduced into the polymerization reactor in the form of a 4% by weight solution in deionized water.

[0108] Example 1: Terpolymer VDF: 70 mol%, TFE: 11 mol%, HFP: 19 mol% (nominal) 3.3 l of deionized water was placed in a vertical autoclave made of AISI 316 steel equipped with a baffle and a stirrer operating at 500 rpm. Next, 6 ml of a 35 wt% aqueous solution of a surfactant CH3(CH2)7CHFCOO-NH4 containing 5 wt% of the above nucleating agent was added. Then, 1.5 ml of a Galden® D02 solution of 33 vol% 1,4-diiodoperfluorobutane and 2 ml of a Galden® D02 solution of 15 vol% bisolefin of the formula H2C=CH-(CF2)6-CH=CH2 were placed in the reactor. Then, the temperature was raised to a reaction temperature of 80 °C, and when it reached that temperature, HFP (hexafluoropropene) was added to cause a pressure fluctuation of 12 bar (absolute pressure). Next, a gas mixture of VDF: 70 mol%, TFE: 11 mol%, and HFP: 19 mol% was added with a compressor until the pressure reached 30 bar (absolute pressure).

[0109] Next, 24 ml of a solution of ammonium persulfate (APS) at 4 wt% in deionized water was supplied. By supplying the above gas mixture, the polymerization pressure was maintained constant.

[0110] When the gas mixture reached 140 g, 2 ml of a Galden® D02 solution of 15 vol% bisolefin was placed in the reactor, and then the gas mixture was introduced up to 450 g every 120 grams.

[0111] When the gas mixture reached 390 g, 9 ml of a Galden® D02 solution of 33 vol% 1,4-diiodoperfluorobutane and 8 ml of an aqueous deionized solution of 4 wt% ammonium persulfate (APS) were supplied.

[0112] When 600 g of gas was supplied, the reactor was cooled to room temperature, the resulting latex was stripped in the autoclave, then withdrawn, degassed, and post-treated by coagulation.

[0113] The recovered polymer was washed with deionized water and dried at 90 °C for 16 hours.

[0114] Comparative Example 2: Terpolymer VDF: 70 mol%, TFE: 11 mol%, HPF: 19 mol% (nominal) The same procedure as in Example 1 described above was followed, but 6 ml of an aqueous solution of 45 wt% ammonium salt of perfluoro surfactant C6O4 containing 15 wt% of the above nucleating agent was added.

[0115] Coagulation procedure 250 ml of latex was poured into 3 liters of a stirred 2 g / L aqueous solution of Al2(SO4)3 using a dropping funnel. When the latex was poured in within 10 minutes, the water became slightly opaque. After a few minutes, nucleation occurred and larger particles were formed. The water began to clear and the particle size increased until the water was completely clear. Thereafter, the water was removed by filtration, and the resulting flaky polymer was washed by stirring with another amount of water for 10 minutes. The polymer was filtered and washed 5 more times, and then dried overnight in an oven at 90 °C.

[0116]

Table 1

[0117] From the results summarized in Table 1, it can be seen that the partially fluorinated surfactant CH3(CH2)7CHFCOO-NH4 according to the present invention is suitable for the preparation of an aqueous dispersion of fluorinated polymer particles containing repeating units derived from VDF such as VDF-HFP-TFE copolymer, and these fluorinated polymer particles have characteristics such as the same composition, glass transition, and molecular weight as those obtained with fluorinated polymers synthesized using perfluoro C6O4 surfactant.

[0118] Furthermore, the partially fluorinated surfactant CH3(CH2)7CHFCOO-NH4 was evaluated according to the carbon dioxide (CO2) generation test (OECD / TG301B). Since CH3(CH2)7CHFCOO-NH4 reached 60% decomposition, which meets the criteria for the 10-day window, it satisfied the definition of an easily biodegradable chemical substance. Furthermore, at the end of the test, i.e., on the 31st day, it showed an average decomposition rate of 71% (see Table 2 below).

[0119]

Table 2

[0120] Therefore, the partially fluorinated surfactant CH3(CH2)7CHFCOO-NH4 is suitable for preparing a fluorinated polymer by free radical polymerization in an aqueous medium and stabilizing the dispersion of the obtained fluorinated polymer, while being advantageously an easily biodegradable chemical substance.

Claims

1. C ２ ~C ３ A method for producing an aqueous dispersion containing particles of a fluorinated polymer (F) containing repeating units derived from hydrofluoroolefin (HFO), comprising the formula (I): R-CFX-P, formula (II): P-CFX-(CH ２ )( ｎ -CFX-P, and formula (III): R-CF(-P) ２ In the presence of at least one partially fluorinated surfactant (S) selected from the group consisting of compounds of, at least one C ２ ~C ３ Free radical polymerization of hydrofluoroolefin (HFO) in an aqueous medium, in formulas (I) to (III), - R is an optionally branched C ３ ~C １６ alkyl or alkenyl chain, which may optionally contain one or more chain heteroatoms selected from N, O, and S, may optionally contain a carbonyl group, may optionally contain one or more halogen atoms selected from Cl, Br, and I, and may optionally contain a C ３ ~C ８ and may optionally contain an aliphatic ring. - n is an integer from 2 to 16, -P is -COO-M, -SO ３ -M, or -PO ３ -M, where M is H, or an alkali metal, or an ammonium group N(R') ４ and R' is the same or different in each occurrence and is a hydrogen atom or a C １ to C ６ hydrocarbon group, preferably an alkyl group, - X is H or F, A method.

2. Said C ２ -C ３ The hydrofluoroolefin (HFO) is selected from the group consisting of vinylidene fluoride (VDF), fluoroethylene, cis-1,2-difluoroethylene, trans-1,2-difluoroethylene, trifluoroethylene, 2,3,3,3-tetrafluoropropylene, cis-1,3,3,3-tetrafluoropropylene, trans-1,3,3,3-tetrafluoropropylene, cis-1,2,3,3-tetrafluoropropylene, trans-1,2,3,3-tetrafluoropropylene, 1,1,3,3-tetrafluoropropylene, 1,1,2,3-tetrafluoropropylene, cis-1,2,3,3,3-pentafluoropropylene, trans-1,2,3,3,3-pentafluoropropylene, 1,1,3,3,3-pentafluoropropylene, 1,1,2,3,3-pentafluoropropylene, 3,3,3-trifluoropropylene, 2,3,3-trifluoropropylene, cis-1,3,3-trifluoropropylene, trans-1,3,3-trifluoropropylene, cis-1,2,3-trifluoropropylene, trans-1,2,3-trifluoropropylene, 1,1,3-trifluoropropylene, 1,1,2-trifluoropropylene, and mixtures thereof, according to the method of claim 1.

3. Said C ２ to C ３ The method according to claim 1 or 2, wherein the hydrofluoroolefin (HFO) is vinylidene fluoride or 2,3,3,3-tetrafluoropropylene, preferably vinylidene fluoride.

4. The partial fluorinated surfactant (S) is CH ３ (CH ２ ) ７ CHFCOO-NH ４ or CH ３ -CO-(CH ２ ) ７ CFHCOO-NH ４ The method according to any one of claims 1 to 3.

5. The method according to any one of claims 1 to 4, wherein the fluorinated polymer (F) further comprises repeating units derived from at least one additional fluorinated monomer.

6. The at least one additional fluorinated monomer is selected from the group consisting of cis-1,2-difluoroethylene, trans-1,2-difluoroethylene, trifluoroethylene (TrFE), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), chlorofluoroethylene (CFE), chlorotrifluoroethylene (CTFE), and perfluoroalkyl vinyl ethers (PAVE) of the formula CF ２ =CF-O-R ｆ１ (wherein R ｆ１ is a C １ to C ６ perfluoroalkyl group), the method according to claim 5.

7. The fluorinated polymer (F) is - VDF and TFE; - VDF, TFE and CTFE; - VDF, TFE and PAVE; - VDF, TFE and HFP; - VDF, TFE, HFP and PAVE; - VDF and TrFE; - VDF, TrFE and CFE; - VDF, TrFE and CTFE; - VDF, TrFE and HFP; - VDF and CFE; - VDF and CTFE; - VDF and HFP; - VDF, HFP and PAVE; or - VDF, HFP and CTFE; The method according to any one of claims 1 to 6, which consists essentially of repeating units derived from.

8. The fluorinated polymer (F) further comprises repeating units derived from at least one bis-olefin [bis-olefin (OF)] having the general formula: 【Chemical 1】 (wherein, R １ , R ２ , R ３ , R ４ , R ５ , and R ６ are the same as or different from each other and are H or C １ ~C ５ alkyl; Z may optionally contain an oxygen atom and is preferably a linear or branched C １ ~C １８ hydrocarbon radical (including an alkylene or cycloalkylene radical), or a (per)fluoropolyoxyalkylene radical) The method according to any one of claims 1 to 7.

9. The method according to any one of claims 1 to 8, wherein the fluorinated polymer (F) contains iodine.

10. The method according to any one of claims 1 to 9, which is carried out in the presence of at least one non-functional perfluoropolyether.

11. The method according to any one of claims 1 to 10, which is carried out in the presence of at least one nucleating agent.

12. The method according to any one of claims 1 to 11, wherein the aqueous dispersion containing particles of the fluorinated polymer (F) is an aqueous latex.

13. An aqueous latex obtained by the method according to any one of claims 1 to 12.

14. C ２ ~C ３ At least one fluorinated polymer (F) containing a repeating unit derived from a hydrofluoroolefin (HFO), and a compound of formula (I) R-CFX-P (I), formula (II) P-CFX-(CH ２ ) ｎ -CFX-P (II), and formula (III) R-CF(-P) ２ compound (In formulas (I) to (III), - R is an optionally branched C ３ ~C １６ alkyl or alkenyl chain, which may optionally contain one or more chain heteroatoms selected from N, O, and S, may optionally contain a carbonyl group, may optionally contain one or more halogen atoms selected from Cl, Br, and I, and may optionally contain a C ３ ~C ８ aliphatic ring, - n is an integer from 2 to 16, -P is -COO-M, -SO ３ -M, or -PO ３ -M, where M is H, or an alkali metal, or an ammonium group N(R') ４ and R' is the same or different in each occurrence, and is a hydrogen atom or a C １ to C ６ hydrocarbon group, preferably an alkyl group, - X is H or F) An aqueous latex comprising at least one partially fluorinated surfactant (S) selected from the group consisting of.

15. The aqueous latex according to claim 13 or 14, wherein the fluorinated polymer (F) is in the form of primary particles having an average primary particle size of 50 to 350 nm measured according to ISO 22412.

16. Use of the aqueous latex according to any one of claims 13 to 15 in coating, sealing, or gasket applications.

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