Dispersible ionomer powder and method for producing same

Abstract

To provide dispersible ionomer powders, a method for their manufacture, and methods of using the same, notably for coating applications.SOLUTION: The present invention relates to certain dispersible ionomer powders made of particles consisting of quasi-spherical hollow agglomerates of elementary particles, to a method for their manufacture involving spray-drying of a latex of the ionomer, and to methods of using the same, notably for coating applications.SELECTED DRAWING: None

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to European Patent Application Publication No. 18204459.4, filed November 5, 2018, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present invention relates to certain dispersible ionomer powders, methods for their preparation and use, particularly for coating applications. [Background technology]

[0003] Fluorinated ionomers containing carboxylic or sulfonic acid groups, more specifically perfluorosulfonic acid (PFSA) polymers, are semi-crystalline materials that are known to be very difficult to dissolve / disperse in solvents unless extreme conditions are used (i.e., underwater pressure at 250°C).

[0004] In practice, the as-polymerized material is typically provided in the form of a latex of polymer precursors that must undergo hydrolysis to achieve ion exchange capacity. Upon coagulation and hydrolysis, the acid form material could be redispersed in water, optionally in admixture with a small amount of alcohol solvent, simply by extensive heat treatment to provide dispersed particles in said aqueous phase.

[0005] Currently, end users may need to formulate the acid form materials as coating compositions based on solvents other than water, for example, for impregnation into various substrates, and therefore the availability of easily dispersible powders of the fluorinated ionomers would be highly beneficial in the market space.

[0006] In this area, therefore, the document US Patent Application Publication No. 2008 / 0227875 discloses solid and liquid compositions containing particles of highly fluorinated ion-exchange polymers with sulfonate functionality. Liquid aqueous compositions are prepared by dispersing the polymer in an aqueous medium under harsh conditions of high temperature and high agitation. Solid compositions can be prepared by removing the liquid components of the aqueous liquid composition from the liquid composition by evaporation at a temperature below the coalescence temperature of the ion-exchanged polymer in the composition. By "coalescence temperature" is meant the temperature at which the dry solid of the polymer hardens into a stable solid that cannot be redispersed in water or other polar solvents under mild conditions, i.e., room temperature / atmospheric pressure. This document teaches that the coalescence temperature varies with the polymer composition, with preferred conditions being those in which the liquid components are removed by heating to a temperature below about 100°C. Techniques for this removal include freeze-drying and spray-drying at temperatures below the coalescence temperature. The result of this method is a redispersible powder composition of the fluoroionomer.

[0007] Similarly, U.S. Patent Application Publication No. 2008 / 0160351 is directed to a method for producing a dispersion of a highly fluorinated ion-exchange polymer, comprising the steps of atomizing a dispersion of the polymer in an organic liquid in a heated gas and redispersing the particles thus obtained in a second liquid. In the examples, a fluoroionomer dispersion was first prepared in water under relatively harsh conditions in a liquid medium containing about 20-25% alcohol (NPA); the alcohol / water dispersion was then spray-dried in a nitrogen flow gas maintained at a temperature of 170-210°C, resulting in particles with a residual moisture content of about 4-5% by weight, a particle size of about 25-40 μm, and a bulk density of 30-50 g / L. The powder thus obtained was easily redispersible in liquid media of different compositions at room temperature.

[0008] Furthermore, the document China Patent No. 103044698B is directed to a method for producing a membrane, which comprises dissolving a perfluorinated sulfonic acid resin in a low boiling point solvent to obtain a solution with a low solid content of 3-15 wt %; in a second step, filtering and spray-drying the solution to obtain a perfluorinated sulfonic acid resin powder; in a subsequent step, redissolving the powder thus obtained in a high boiling point solvent to prepare a solution with a high solid content of 25-50 wt %; and removing bubbles from the solution, coating the solution on a solid surface to form a film, drying, and rolling to obtain a perfluorosulfonic acid ion exchange membrane.

[0009] Furthermore, the document US2011 / 0240559 describes a method for purifying a liquid PFSA dispersion by contacting it with solid particulates of PFSA having SO3H groups; this solid particulate PFSA having acid groups is obtained from a perfluorosulfonic acid precursor prepared by emulsion polymerization and having sulfonyl fluoride groups, and further subjected to coagulation, hydrolysis and drying. This document does not describe the hydrolysis of the PFSA precursor in latex form, nor the spray drying technique.

[0010] Now, although the problem of providing redispersible fluorinated ionomer powders has already been addressed in the prior art, co-handling of the resulting dispersions to formulate coating compositions remains a challenge, since the achievable concentrations remain low and the corresponding viscosities in the liquid state are very often too low to be compatible with standard coating liquid formulation techniques, so that the viscosity of the resulting formulations must be corrected by the addition of viscosity modifiers and / or thickeners that can subsequently remain incorporated in the final coated / impregnated article.

[0011] Therefore, there remains a need for dispersible fluoroionomer powders and methods for providing fluoroionomer powders therefrom that could address unmet needs in the market, including providing high solids, high viscosity formulations in a variety of solvents with a facile manufacturing methodology. Summary of the Invention

[0012] Faced with this technical problem, the Applicant has found a method for producing ionomer powders that is particularly advantageous in that it avoids the use of harsh conditions and that results in particles with particularly advantageous properties, in particular in terms of the achievable liquid viscosity of formulations therefrom.

[0013] Thus, in a first aspect, the present invention provides a compound comprising -SO3X a , -PO3X a and -COOX a (where X a at least one ionizable polymer [ionomer (I)] containing a plurality of ionizable groups selected from the group consisting of H, ammonium groups, or metals, preferably monovalent metals; X 2. A method for producing a powder material [material (P)] consisting of a plurality of particles of Process (1):-SO2X X , -PO2X X and -COX x (where X x is a halogen, in particular F or Cl), P As-polymerized aqueous latex [latex(I)] containing particles p )]; Step (2): Ionomer (I X ) without causing any significant coagulation, to obtain an aqueous latex of particles of the group -SO2X X , -PO2X X and -COX x (where X x is F or Cl) to the corresponding group -SO3X a , -PO3X a and -COOX a (where X a is H, an ammonium group, or a monovalent metal),x contacting the hydrolysis product with a basic hydrolysis agent [reagent (B)]; Optionally, step (3): treating the latex (I) to at least partially remove any residues of the reagent (B) and / or other contaminants. x ) with at least one ion exchange resin; Step (4): To obtain the material (P), a latex (I) is optionally purified. x ) spray drying; The present invention relates to a method comprising:

[0014] In a second aspect, the present invention provides a powdered material [material (P)] obtainable by the process as detailed above, comprising -SO3X a , -PO3X a and -COOX a (where X a at least one fluorinated ionomer [ionomer (I) is a fluorinated ionomer containing a plurality of ionizable groups selected from the group consisting of H, ammonium groups, or metals, preferably monovalent metals]; X )], which is composed of multiple particles the particles comprise pseudo-spherical hollow agglomerates of elementary particles; - the hollow agglomerates have an average particle size of 1 to 150 μm; and The particles relate to a powdered material [material (P)] having an average diameter of 15 to 150 nm.

[0015] In particular, the applicant has found that the process of the present invention, which does not involve any steps of solidification and then re-dissolving of the precursor / ionomer, is particularly efficient from an economic point of view, uses milder conditions for processing the precursor into a powdered material, and is therefore highly advantageous in itself. Furthermore, the process as detailed above provides a powdered material with a particularly advantageous particle microstructure, which microstructure provides an increased liquid viscosity so that said powdered material is easily re-dissolved and formulations therefrom can match the viscosity requirements of many coating / liquid processing techniques without the need for the addition of erroneous viscosity enhancers and / or thickeners.

[0016] Ionizable polymers [ionomers (I X )] and ionomer precursor [precursor (I P )] The other name for the ionomer of the present invention (I X ) and its precursor (I P ) are generally fluorinated, i.e., comprise repeat units derived from ethylenically unsaturated monomers containing at least one fluorine atom, and may further comprise repeat units derived from at least one hydrogen-containing monomer, where the term "hydrogen-containing monomer" means an ethylenically unsaturated monomer that contains at least one hydrogen atom and no fluorine atoms.

[0017] As mentioned above, the ionomer (I X ) is -SO3X a , -PO3X a and -COOX a (where X a contains a plurality of ionizable groups selected from the group consisting of H, ammonium groups or metals, preferably monovalent metals, while the precursor (I p ) is -SO2X X , -PO2X X and -COX x (where X x is a halogen, in particular F or Cl) P )].

[0018] Ionomer (I X Counterion X in the ionizable group of a Examples of preferred monovalent metals suitable for the cation include Li, K, and Na, where Li is, for example, Li + In connection with its use in the domain of secondary batteries and other electrochemical devices based on the / Li redox couple, ionomers (I X ) may be preferred for certain fields of use.

[0019] Generally, ionomers (IX ) contains said ionizable group as a pendant group covalently attached to the hydrolyzed repeat unit derived from the functional monomer (hereinafter monomer (X)). Similarly, the precursor (I P ) comprises said hydrolyzable group as a pendant group covalently bonded to a repeat unit derived from said functional monomer (hereinafter monomer (X)).

[0020] In relation to a particular monomer, the expression "hydrolyzed repeat unit derived from" is intended to refer to a repeat unit that is first derived / obtained directly from polymerizing said particular monomer and then derived / obtained by further modification / elaboration thereof by hydrolysis.

[0021] Ionomer (I X ) can consist essentially of a sequence of hydrolyzed repeat units derived from one or more monomers (X) as detailed above, or can be a copolymer comprising hydrolyzed repeat units derived from one or more monomers (X) and repeat units derived from one or more additional monomers different from monomer (X). Similarly, ionomers (I X ) is obtained from the precursor (I P ) may consist essentially of a sequence of repeat units derived from one or more monomers (X) as detailed above, or may be a copolymer comprising repeat units derived from one or more monomers (X) and one or more additional monomers different from monomer (X).

[0022] Generally, the monomer (X) is a fluorinated monomer, and one or more additional monomers different from the monomer (X) may also be fluorinated monomers. The expression "fluorinated monomer" is intended to encompass ethylenically unsaturated monomers containing at least one fluorine atom.

[0023] According to a particular embodiment of the present invention, an ionomer (I X ) is a mixture of multiple -SO3X as detailed above. a groups, i.e., ionomers (I SO3X According to these embodiments, the precursor (I P ) is a group consisting of multiple groups -SO2X as detailed above X The precursor (P SO2X )

[0024] Ionomer (I SO3X ) is the formula -SO3X as detailed above a One or more monomers (X SO3X ) or may consist essentially of a sequence of multiple repeat units derived from one or more monomers (X SO3X ) and multiple repeating units derived from the monomer (X SO3X ) and one or more additional repeat units derived from different monomers.

[0025] Similarly, the precursor (P SO2X ) is calculated using the formula -SO2X as detailed above. X One or more monomers (X P SO2X ) or may consist essentially of a sequence of multiple repeat units derived from one or more monomers (X P SO2X ) and multiple repeating units derived from the monomer (X P SO2X ) and one or more additional repeating units derived from different monomers. a Suitable preferred ionomers (I SO3X ) is at least one -SO3X a group (where X a is H, an ammonium group or a metal, preferably a monovalent metal), and at least one -SO2X X group (where X xis a halogen), and a plurality of hydrolyzed repeat units derived from at least one ethylenically unsaturated fluorinated monomer [hereinafter monomer (A)] containing -SO2X as detailed above; X These polymers essentially consist of a plurality of repeating units derived from at least one ethylenically unsaturated fluorinated monomer (hereinafter, monomer (B)) that does not contain a group. SO2X ) is at least one -SO2X X and a plurality of repeat units derived from at least one ethylenically unsaturated fluorinated monomer comprising a group and containing at least one monomer (A) as detailed above; and a plurality of repeat units derived from at least one monomer (B) as detailed above.

[0026] As already mentioned above, in relation to the specific monomer (A), the expression "hydrolyzed repeating units derived from" refers to repeating units that are first derived / obtained directly from polymerizing said specific monomer and then from said at least one -SO2X X group (where X X is a halogen) to said at least one -SO3X a group (where X a is intended to refer to a repeat unit derived / obtained by its further modification / elaboration by hydrolysis, converting it to a hydroxy group (H, an ammonium group or a metal, preferably a monovalent metal).

[0027] The phrase "at least one monomer" refers to both types (A) and (B) of monomers and means that one or more monomers of each type are ionomers (I SO3X ) and / or precursor (P SO2X ) In the following, the term "monomer" is used to refer to both one and more than one monomer of a given type.

[0028] Non-limiting examples of suitable monomers (A) are: - Formula: CF2 = CF(CF2)p SO2X X (where X X is a halogen, preferably F or Cl, more preferably F, and p is an integer from 0 to 10, preferably from 1 to 6, more preferably p is equal to 2 or 3; - Formula: CF2 = CF-O-(CF2) m SO2X X (where X X is a halogen, preferably F or Cl, more preferably F, and m is an integer from 1 to 10, preferably from 1 to 6, more preferably from 2 to 4, and even more preferably m is equal to 2); - Formula: CF2 = CF-(OCF2CF(R F1 )) w -O-CF2(CF(R F2 )) y SO2X X (where X X is a halogen, preferably F or Cl, more preferably F; w is an integer of 0 to 2, and R F1 and R F2 are independently C1-C optionally substituted with F, Cl, or one or more ether oxygens. 10 is a fluoroalkyl group, y is an integer of 0 to 6; preferably, w is 1, and R F1 is -CF3, y is 1, and R F2 is F) sulfonyl fluoride fluoroalkoxy vinyl ether; - Formula CF2=CF-Ar-SO2X X (where X X is a halogen, preferably F or Cl, more preferably F, and Ar is a C5-C 15 a sulfonyl halide aromatic fluoroolefin, is.

[0029] Preferably, the monomer (A) has the formula CF2=CF-O-(CF2) mThe sulfonyl fluoride fluorovinyl ether is selected from the group of sulfonyl fluoride fluorovinyl ethers of -SO2F (where m is an integer of 1 to 6, preferably 2 to 4).

[0030] More preferably, monomer (A) is CF2=CFOCF2CF2-SO2F (perfluoro-5-sulfonylfluoride-3-oxa-1-pentene).

[0031] Non-limiting examples of suitable ethylenically unsaturated fluorinated monomers of type (B) are: - C2-C8 perfluoroolefins, such as tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoroisobutylene; - C2-C8 hydrogen-containing fluoroolefins, such as trifluoroethylene (TrFE), vinylidene fluoride (VDF), vinyl fluoride (VF), pentafluoropropylene and hexafluoroisobutylene; - C2-C8 chloro- and / or bromo- and / or iodo-containing fluoroolefins, such as chlorotrifluoroethylene (CTFE) and bromotrifluoroethylene; - Formula CF2=CFOR f1 (where R f1 is C1-C6 fluoroalkyl, for example, -CF3, -C2F5, -C3F7) fluoroalkyl vinyl ether; - in particular the formula CF2=CFOCF2OR f2 (where R f2 includes fluoromethoxyalkyl vinyl ethers of the formula CF2=CFOX0 (where X0 is a C1-C3 fluoro(oxy)alkyl group containing one or more ether oxygen atoms, such as -CF2CF3, -CF2CF2-O-CF3, and -CF3). 12 fluorooxyalkyl vinyl ethers, each of which is a fluorooxyalkyl group; - Formula: TIFF0007758781000001.tif35170 (wherein R f3 , R f4 , R f5 , Rf6 each independently represents a fluorine atom, a C1-C6 fluoro(halo)fluoroalkyl optionally containing one or more oxygen atoms, e.g., —CF3, —C2F5, —C3F7, —OCF3, —OCF2CF2OCF3) Fluorodioxole is.

[0032] Preferably, the monomer (B) is - C2-C8 perfluoroolefins selected from tetrafluoroethylene (TFE) and / or hexafluoropropylene (HFP); - C2 to C8 hydrogen-containing fluoroolefins selected from trifluoroethylene (TrFE), vinylidene fluoride (VDF) and vinyl fluoride (VF); and - A mixture of these is selected among.

[0033] According to these embodiments, preferably, an ionomer (I SO3X ) is a multiple of -SO3X a In these embodiments, the precursor (P) essentially comprises a sequence of a plurality of hydrolyzed repeat units derived from at least one ethylenically unsaturated fluorinated monomer (A) containing at least one sulfonyl fluoride functional group (group -SO2F) and a plurality of repeat units derived from at least one ethylenically unsaturated fluorinated monomer (B). SO2X ) essentially comprises a sequence of a plurality of repeat units derived from at least one ethylenically unsaturated fluoromonomer (A) containing at least one sulfonyl fluoride functional group (group -SOF) and a plurality of repeat units derived from at least one ethylenically unsaturated fluorinated monomer (B).

[0034] Optionally, end groups, impurities, defects and limited amounts (less than 1 mole % based on the total moles of repeating units) of other incorrect units may be present in the ionomer (I SO3X ) or precursor (P SO2XIn addition to the recited repeat units, preferred ionomers (I SO3X ) and / or the preferred precursor (P SO2X ) can be present in

[0035] According to a particular embodiment, an ionomer (I SO3X ) or the corresponding precursor (P SO2X At least one monomer (B) in the ionomer (I) is TFE. SO3X ) is hereby referred to as an ionomer (I TFE SO3X ), while the corresponding precursor (P SO2X ) is the precursor (P TFE SO2X ) would be called

[0036] Preferred ionomers (I TFE SO3X )teeth, (1) A repeating unit derived from tetrafluoroethylene (TFE), which is an ionomer (I TFE SO3X ) repeating units in an amount of generally 50 to 99 mol %, preferably 52 to 98 mol %, based on the total moles of repeating units; (2) at least one -SO3X a group, and (j) Formula: CF2 = CF-O-(CF2) m SO2X X (where X X is a halogen, preferably F or Cl, more preferably F; m is an integer from 1 to 10, preferably from 1 to 6, more preferably from 2 to 4, and even more preferably m is equal to 2), (jj)Formula:Formula:CF2=CF-(OCF2CF(R F1 )) w -O-CF2(CF(R F2 )) y SO2X X (where X Xis a halogen, preferably F or Cl, more preferably F; w is an integer of 0 to 2, and R F1 and R F2 are independently C1-C optionally substituted with F, Cl, or one or more ether oxygens. 10 is a fluoroalkyl group, y is an integer of 0 to 6; preferably, w is 1, and R F1 is -CF3, y is 1, and R F2 is F); and (jjj) A mixture of these and a hydrolyzed repeating unit derived from at least one monomer selected from the group consisting of an ionomer (I TFE SO3X ) hydrolyzed repeating units in an amount of generally 1 to 50 mol %, preferably 2 to 48 mol %, based on the total moles of repeating units; (3) optionally, at least one hydrogen-containing monomer and / or fluorinated monomer different from TFE, preferably hexafluoropropylene, formula CF2=CFOR' f1 (where R' f1 is C1-C6 perfluoroalkyl, for example, -CF3, -C2F5, -C3F7); for example, perfluoroalkyl vinyl ethers of the formula CF2=CFOCF2OR' f2 (where R' f2 is a C1-C6 perfluoroalkyl, for example a C1-C6 perfluorooxyalkyl having one or more ether groups such as -CF3, -C2F5, -C3F7 or -C2F5-O-CF3), O1 (where R' O1 is a C2-C alkyl group having one or more ether groups 12 repeating units derived from perfluorinated monomers generally selected from the group consisting of perfluoro-oxyalkyl vinyl ethers of ionomers (I TFE SO3X) repeating units in an amount of generally 0 to 45 mol %, preferably 0 to 40 mol %, based on the total moles of repeating units The polymer is selected from the group consisting essentially of:

[0037] Without being inconsistent, the preferred ionomers (I TFE SO3X ) can be obtained from the preferred precursor (P TFE SO2X )teeth, (1) A repeating unit derived from tetrafluoroethylene (TFE), which is a precursor (P TFE SO2X ) repeating units in an amount of generally 50 to 99 mol %, preferably 52 to 98 mol %, based on the total moles of repeating units; (2)(j) Formula: CF2 = CF-O-(CF2) m SO2X X (where, X is a halogen, preferably F or Cl, more preferably F; m is an integer from 1 to 10, preferably from 1 to 6, more preferably from 2 to 4, even more preferably m is equal to 2); (jj) Formula: CF2 = CF-(OCF2CF(R F1 )) w -O-CF2(CF(R F2 ))X X (where X X is a halogen, preferably F or Cl, more preferably F; w is an integer of 0 to 2, and R F1 and R F2 are independently C1-C optionally substituted with F, Cl, or one or more ether oxygens. 10 is a fluoroalkyl group, y is an integer of 0 to 6; preferably, w is 1, and R F1 is -CF3, y is 1, and R F2 is F); and (jjj) A mixture of these A repeating unit derived from at least one monomer selected from the group consisting of a precursor (P TFE SO2X ) repeating units in an amount of generally 1 to 50 mol %, preferably 2 to 48 mol %, based on the total moles of repeating units; (3) optionally, at least one hydrogen-containing monomer and / or fluorinated monomer different from TFE, preferably hexafluoropropylene, formula CF2=CFOR' f1 (where R' f1 is C1-C6 perfluoroalkyl, for example, -CF3, -C2F5, -C3F7); for example, perfluoroalkyl vinyl ethers of the formula CF2=CFOCF2OR' f2 (where R' f2 is a C1-C6 perfluoroalkyl, for example, a C1-C6 perfluorooxyalkyl having one or more ether groups such as CF3, -C2F5, -C3F7 or -C2F5-O-CF3), including perfluoroalkyl-methoxy-vinyl ethers of the formula CF2=CFOR' O1 (where R' O1 is a C2-C alkyl group having one or more ether groups 12 repeat units derived from perfluorinated monomers generally selected from the group consisting of perfluoro-oxyalkyl vinyl ethers of the precursor (P TFE SO2X ) repeating units in an amount of generally 0 to 45 mol %, preferably 0 to 40 mol %, based on the total moles of repeating units The polymer is selected from the group consisting essentially of:

[0038] According to a particular embodiment, the preferred ionomers (I TFE SO3X ) is generally the ionomer (I TFE SO3X ) based on the total moles of repeating units of (k) 55 to 95 mol %, preferably 65 to 93 mol %, of repeating units derived from TFE; (kk) 5 to 45 mol%, preferably 7 to 35 mol%, of at least one -SO3Xa a hydrolyzed repeat unit derived from monomer (2) comprising a group and as detailed above; (3) 0 to 25 mol %, preferably 0 to 20 mol %, of repeating units derived from the fluorinated monomer (3) other than TFE as detailed above. It essentially consists of:

[0039] Instead of their corresponding hydrolyzed counterparts, preferred precursors (P) containing units derived from monomer (2) as detailed above are TFE SO2X ), the same applies, mutatis mutandis.

[0040] According to certain other embodiments, ionomers (I SO3X ) or the corresponding precursor (P SO2X At least one monomer (B) in the ionomer (I) is VDF. SO3X ) is an ionomer (I VDF SO3X ), while the corresponding precursor (P SO2X ) is the precursor (P VDF SO2X ) would be called

[0041] Preferred ionomers (I VDF SO3X )teeth, (1) A repeating unit derived from vinylidene fluoride (VDF), which is an ionomer (I VDF SO3X ) repeating units in an amount of generally 55 to 99 mol %, preferably 70 to 95 mol %, based on the total moles of repeating units; (2) at least one -SO3X a group, and (j) Formula: CF2 = CF-O-(CF2) m SO2X X (where X Xis a halogen, preferably F or Cl, more preferably F, and m is an integer from 1 to 10, preferably from 1 to 6, more preferably from 2 to 4, and even more preferably m is equal to 2); (jj) Formula: CF2 = CF-(OCF2CF(R F1 )) w -O-CF2(CF(R F2 )) y SO2X X (where X X is a halogen, preferably F or Cl, more preferably F; w is an integer of 0 to 2; and R F1 and R F2 are independently C1-C optionally substituted with F, Cl, or one or more ether oxygens. 10 is a fluoroalkyl group, y is an integer of 0 to 6; preferably, w is 1, and R F1 is -CF3, y is 1, and R F2 is F); and (jjj) A mixture of these and a hydrolyzed repeating unit derived from at least one monomer selected from the group consisting of an ionomer (I VDF SO3X ) hydrolyzed repeating units in an amount of generally 1 to 45 mol %, preferably 5 to 30 mol %, based on the total moles of repeating units; (3) Optionally, repeating units derived from at least one hydrogen-containing monomer or fluorinated monomer other than VDF, which may be an ionomer (I VDF SO3X ) repeating units in an amount of generally 0 to 30 mol %, preferably 0 to 15 mol %, based on the total moles of repeating units of The polymer is selected from the group consisting essentially of:

[0042] According to a particular embodiment, the preferred ionomers (I VDF SO3X ) is generally the ionomer (I VDF SO3X) based on the total moles of repeating units of (1) 55 to 95 mol %, preferably 70 to 92 mol %, of repeating units derived from VDF; (2) 5 to 40 mol%, preferably 8 to 30 mol%, of at least one -SO3X a a hydrolyzed repeat unit comprising a group and derived from at least one monomer (2) as detailed above; (3) 0 to 15 mol %, preferably 0 to 10 mol %, of repeating units derived from the hydrogen-containing monomer or fluorinated monomer (3) other than VDF as described above in detail. It is a polymer consisting essentially of

[0043] Ionomer (I X ) and / or their precursors (I P ) is represented by the formula: R A R B =CR C -T-CR D =R E R F (where R A , R B , R C , R D , R E and R F is selected from the group consisting of H, F, Cl, C1-C5 alkyl groups and C1-C5 (per)fluoroalkyl groups, and T is preferably a linear or branched C1-C5 alkyl group, optionally containing one or more ether oxygen atoms, which is at least partially fluorinated. 18 It may further comprise repeat units derived from at least one bis-olefin [bis-olefin (OF)], which is an alkylene or cycloalkylene group or a (per)fluoropolyoxyalkylene group.

[0044] The bis-olefins (OF) are preferably represented by the formulae (OF-1), (OF-2) and (OF-3): TIFF0007758781000002.tif32170 (wherein j is an integer comprised between 2 and 10, preferably between 4 and 8, and R1, R2, R3 and R4, which are equal to or different from each other, are selected from the group consisting of H, F, C1-C5 alkyl groups and C1-C5 (per)fluoroalkyl groups); TIFF0007758781000003.tif32170 (wherein each A, which is equal to or different from each other and at each occurrence, is independently selected from the group consisting of H, F, and Cl; each B, which is equal to or different from each other and at each occurrence, is independently selected from the group consisting of H, F, Cl, and OR B (where R B is a branched or straight-chain alkyl group which may be partially, substantially or fully fluorinated or chlorinated; E is a divalent group having 2 to 10 carbon atoms, optionally fluorinated, which may have inserted ether linkages; preferably, E is -(CF2) m - group (where m is an integer between 3 and 5 inclusive); a preferred bis-olefin of the (OF-2) type is F2C=CF-O-(CF2)5-O-CF=CF2; TIFF0007758781000004.tif28170 (wherein E, A and B have the same meanings as defined above, and R5, R6 and R7, which may be equal to or different from each other, are selected from the group consisting of H, F, C1-C5 alkyl groups and C1-C5 (per)fluoroalkyl groups). The compound is selected from the group consisting of:

[0045] Ionomer (I X ) or their precursors (I P ) further comprises repeating units derived from at least one bis-olefin (OF), the ionomer (I X ) or their precursors (I P ) may be optionally ionomer (I X ) or their precursors (I PThe repeating units derived from the at least one bis-olefin (OF) are typically contained in an amount of 0.01 mol % to 1.0 mol %, preferably 0.03 mol % to 0.5 mol %, more preferably 0.05 mol % to 0.2 mol %, based on the total moles of repeating units of OF.

[0046] In some cases, an ionomer (I X ) or their precursors (I P The amount of ionizable or hydrolyzable groups in the ionomer (I X ) or precursor (I P Preferably, the total amount of ionizable or hydrolyzable groups is at least 0.55, preferably at least 0.65, more preferably at least 0.75 meq / g based on the total weight of the copolymer.

[0047] Ionomer (I X ) or precursor (I P There is no practical limit as to the maximum amount of ionizable or hydrolyzable groups contained in the ionomer (I). X ) or precursor (I P It is generally understood that the selenium is present in an amount of at most 3.50 meq / g, preferably at most 3.20 meq / g, more preferably at most 2.50 meq / g, based on the total weight of the selenium.

[0048] In step (1) of the method of the present invention, a precursor (I P An as-polymerized aqueous latex containing particles of

[0049] The expression "as-polymerized aqueous latex" is hereby given its general meaning in the art and means an aqueous dispersion containing stably dispersed particles of polymer as obtained from emulsion polymerization. The specific emulsion polymerization technique used to prepare said latex is not particularly limited. Techniques in which said latex is prepared by emulsion polymerization in an aqueous medium in the presence of one or more emulsifiers and techniques in which no emulsifiers are used can be equally effective.

[0050] Latex (I P ) for use in emulsion polymerization in an aqueous polymerization medium for the preparation of said latex (I p Non-limiting examples of emulsifiers, particularly fluorinated emulsifiers, that may be included in the emulsion include, among others: (a')CF3(CF2) n0 COOM' (wherein n0 is an integer ranging from 4 to 10, preferably from 5 to 7, preferably n0 is equal to 6, and M' represents NH4, Na, Li or K, preferably NH4); (b')[R1-O n -LA - ]Y + wherein R1 is a linear or branched, partially or fully fluorinated aliphatic group which may contain an ether linkage; n is an integer; L is a linear or branched alkylene group which may be non-fluorinated, partially fluorinated or fully fluorinated and which may contain an ether linkage; A - is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion, and phosphonate; and Y + is hydrogen, ammonium or an alkali metal cation), and within class (b'), (b'-1)T-(C3F6O) n1 (CFYO) m1 CF2COOM'' (where T is a Cl atom or a x F 2x+1-x’ Cl x’O (wherein x is an integer ranging from 1 to 3, and x' is 0 or 1), n1 is an integer ranging from 1 to 6, m1 is 0 or an integer ranging from 1 to 6, M'' is NH4, Na, Li, or K, and Y is F or -CF3; (b'-2)R f -(OCF2CF2) k-1 -O-CF2-COOX a (IA) (where R f is a C1-C3 perfluoroalkyl group optionally containing one or more ether oxygen atoms, k is 2 or 3, and X a is a monovalent metal and the formula NR N 4 (where each occurrence is equal or different R N is a hydrogen atom or a C1-C3 alkyl group), (b'-3)F-(CF2CF2) n2 -CH2-CH2-X*O3M''' (wherein X* is a phosphorus or sulfur atom, preferably X* is a sulfur atom, M''' represents NH4, Na, Li or K, and n2 is an integer ranging from 2 to 5, preferably n2 is equal to 3). Mention may in particular be made of [R1-O n -LA - ]Y + ; (c')AR bf -B bifunctional fluorinated surfactants, where A and B, which may be equal to or different from each other, are represented by the formula -(O) p CFY″-COOM* (wherein M* represents NH4, Na, Li or K, preferably M* represents NH4, Y″ is F or —CF3, and p is 0 or 1, and R bf is AR bf - B is a divalent (per)fluoroalkyl chain or (per)fluoropolyether chain whose number average molecular weight is in the range of 300 to 1800; (d') Formula (II): TIFF0007758781000005.tif22170 (wherein X1, X2 and X3, which are equal to or different from each other, are independently selected from the group consisting of H, F and C1-C6 (per)fluoroalkyl groups optionally containing one or more catenary or non-catenary oxygen atoms; L is a bond or a divalent group; R F is a divalent fluorinated C1-C3 bridging group, and Y is an anionic functional group. cyclic fluoro compounds; and (e') their mixtures Examples include:

[0051] The latex is an aqueous latex, i.e., a precursor (I P ) is a liquid medium in which particles are dispersed in an aqueous medium, i.e. a medium consisting mainly of water; small amounts of other solvents and / or raw materials / auxiliaries used in the polymerization (residues of initiators, chain transfer agents, stabilizers, emulsifiers, etc.) may nevertheless be present in said latex.

[0052] In step (2), Tex (I p ) is an ionomer (I X ) without causing any significant coagulation, to obtain an aqueous latex of particles of the group -SO2X X , -PO2X X and -COX x (where X x is F or Cl) to the corresponding group -SO3X a , -PO3X a and -COOX a (where X a is contacted with a basic hydrolysis agent [agent (B)] under conditions such that it is at least partially converted to H, an ammonium group, or a metal, preferably a monovalent metal.

[0053] The selection of the basic hydrolysis agent is not particularly limited, provided that it can effectively induce the desired hydrolysis reaction.

[0054] Generally, inorganic bases, especially inorganic hydroxides of alkali or alkaline earth metals, can be used, although organic bases can also be effective for this purpose. Among the inorganic bases that have been found to be useful, mention may be made of KOH, NaOH, LiOH, Mg(OH)2, and Ca(OH)2.

[0055] Generally, the agent (B) is used in excess relative to the total amount of equivalents of groups to be hydrolyzed.

[0056] The temperature and stirring in step (2) are adjusted to the original latex (I P ) and the resulting latex (I X is particularly controlled in combination with the overall concentration of agent (B) to prevent any significant coagulation of the septum.

[0057] Nevertheless, it is understood that a small amount of coagulation and / or sediment formation may occur. In step (2), coagulation is carried out to remove the original latex (I P ) or the resulting latex (I X ) in an amount less than 5% by weight of the total solids is considered an embodiment in which any significant coagulum occurs.

[0058] During step (2), advantageously, said original latex (I p ) dispersed in the precursor (I p The average particle size of the particles of the resulting latex (I) is not significantly altered, so that the average particle size of the resulting latex (I) is advantageously X ) dispersed in ionomer (I x The average particle size of the particles of the original latex (I p ) into the precursor (I p ) particles are essentially the same.

[0059] Generally, the original latex (I p ) dispersed in the precursor (I p) have an average particle size advantageously in the range of 15 to 150 nm; more particularly, said average particle size is advantageously at least 30 nm, preferably at least 50 nm and / or advantageously at most 140 nm, preferably at most 120 nm, most preferably at most 100 nm.

[0060] Similarly, the resulting latex (I X ) dispersed in ionomer (I X ) have an average particle size advantageously in the range of 15 to 150 nm; more particularly, said average particle size is advantageously at least 30 nm, preferably at least 50 nm and / or advantageously at most 140 nm, preferably at most 120 nm, most preferably at most 100 nm.

[0061] Latex (I p ) and / or latex (I X The average primary particle size of the particles dispersed in the dispersion medium can be determined, inter alia, by photon correlation spectroscopy (PCS) (also known as dynamic laser light scattering (DLLS) technique) according to the method described in B. Chu "Laser light scattering", Academic Press, New York (1974), in accordance with the ISO 13321 standard.

[0062] It is well known to those skilled in the art that PCS provides an estimate of the mean hydrodynamic diameter. For purposes of the present invention, the term "mean particle size" is intended in its broadest sense, which relates to the measurement of hydrodynamic diameter. For purposes of the ISO 13321 standard, the term "mean particle size" of primary particles refers to the harmonic intensity mean particle size X as determined by equation (C.10) of Annex C of ISO 13321. PCS It should also be understood that the term "is" is intended to mean "is" or "is not."

[0063] By way of example, the average primary particle size can be measured using a Malvern Zetasizer 3000 HS instrument at a 90° scattering angle using a 10 mV He-Ne laser source and PCS software (Malvern 1.34 version). The average particle size is preferably measured on a latex sample that has been suitably diluted with double-distilled water and filtered to 0.2 μm on a Millipore filter.

[0064] Step (2) is a process of mixing reagent (B) and latex (I P ), and the resulting latex (I X The method may further comprise a step of contacting the latex (I) with at least one neutralizing agent [reagent (N)] different from agent (B). The choice of agent (N) is not particularly limited; generally, this step of contacting with agent (N) optionally neutralizes the latex (I) in their acidic forms, i.e., their -SO3H, -PO3H, and -COOH. X ) are effective in restoring the ionizable groups of the (N) reagent. Reagents (N) that have found utility include organic and inorganic acids.

[0065] Therefore, the result of step (2) of the method of the present invention is a latex (I) which may contain residues of reagent (B) and / or other contaminants. X The expression "contaminant" refers to latex (I X ) dissolved / contained in a liquid medium, X ) is understood hereby to encompass any other material / compound other than latex (I). Exemplary embodiments of these materials / compounds include latex (I P ), and in fact, latex (I X These may be residues from polymerization initiators, suspending agents, emulsifiers, buffers and other adjuvants which are known to exist as ionized / ionizable species in the polymer.

[0066] According to a particular embodiment, the method of the present invention therefore comprises the step of treating said latex (I) with a solvent to at least partially remove said residues of agent (B) and / or other contaminants.x It may be appropriate to include a step (3) of contacting the soluble solids with at least one ion exchange resin.

[0067] In the remainder of the text, the expression "ion exchange resin", for the purposes of the present invention, understood in both the plural and the singular, is intended to mean a solid, insoluble matrix (or support structure), usually in the form of beads of reduced size (e.g., 0.1-5 mm), generally fabricated from an organic polymer substrate, having active sites (ion exchange sites) on its surface that readily capture and release (i.e., exchange) ions in a process called ion exchange.

[0068] The ion exchange generally does not undergo structural changes in the ion exchange step (3).

[0069] Ion exchange resins can be natural or synthetic materials capable of exchanging their own ions for ions present in the liquid with which they are contacted.

[0070] Thus, during step (3), the ions are advantageously added to the latex (I X ) and the ion exchange resin. P The anions derived from any emulsifier used for the preparation of the latex (I) are advantageously X ) onto the ion exchange resin. At the same time, the anions that were initially fixed on the ion exchange resin are advantageously transferred to the latex (I X )

[0071] Ion exchange resins are typically composed of synthetic beads, each a polymer matrix containing ion exchange sites on its surface and within the matrix itself.

[0072] Preferably, the polymer matrix of the ion exchange resin contains repeating units derived from styrene (so-called polystyrene matrix) or (meth)acrylic esters (so-called acrylic matrix). The required exchange sites can be introduced after polymerization or by using a substituted monomer. Preferably, the polymer matrix is ​​a crosslinked matrix. Crosslinking is usually achieved by adding a small proportion of divinylbenzene during polymerization. Non-crosslinked polymers are rarely used due to their tendency to change dimensions depending on the ions they bind. More preferably, the polymer matrix is ​​a crosslinked polystyrene matrix.

[0073] There are many different types of ion exchange resins that are made to selectively favor one or several different types of ions.

[0074] Anions can only be exchanged with other anions and cations with other cations. The ion exchange resins used are therefore X It is also understood that the contaminants / acid groups may be adsorbed onto the ion exchange resin by a mechanism different from ion exchange.

[0075] Anion exchange resins have positively charged ion exchange sites to which anions are bound, and cation exchange resins have negatively charged ion exchange sites to which cations are bound. Ion exchange resins are usually prepared with bound ions that have low affinity for the exchange sites. Anion-containing latex (I X When cations (chlorides) come into contact with an ion exchange resin, the anions with the greatest affinity for the exchange sites generally displace those with the lowest affinity. Therefore, it is important that the ion exchange resin contain anions with a lower affinity than those that need to be exchanged. Anion exchange resins often displace chlorides (Cl) due to their lower affinity for the exchange sites. -) or hydroxyl (OH - ) ions are used.

[0076] Preferably, the ion exchange resin used in step (3) of the process of the present invention comprises at least one anion exchange resin as defined above to remove anionic contaminants / residues as detailed above. Generally, the latex (I P The emulsifiers used in the preparation of ) are anionic, preferably metal salts or quaternary ammonium salts of fluorinated species, and therefore anion exchange resins are generally considered more suitable for their sequestration and removal.

[0077] Non-limiting examples of positively charged ion exchange sites on anion exchange resins include: TIFF0007758781000006.tif25170 (wherein each occurrence of R, which may be equal or different, independently represents C1 to C 12 a hydrocarbon group or a hydrogen atom, and each occurrence of E, which is equal or different, is independently a divalent hydrocarbon group containing at least one carbon atom. As illustrated in.

[0078] Preferably, the positively charged ion exchange sites of the anion exchange resin are Selected in TIFF0007758781000007.tif21170.

[0079] The choice of anion to be immobilized on the positively charged ion exchange sites is not critical, provided that it typically has a lower affinity for said sites than the anions of the contaminants / residues to be removed.

[0080] The anionic ion exchange resin preferably has, on its positively charged ion exchange sites, the following: F - (The pKa of HF is 3.17); OH - (The pKa of HO is 15.75); CHO -(The pKa of CH3OH is 15.5); ((CH3)2CHO - (The pKa of (CH3)2CHOH is 16.5); (CH3)3CO - (The pKa of (CH3)3COH is 17)

[0081] The anion exchanger preferably has a counterion corresponding to an acid with a pKa value of at least 5, even more preferably at least 7.

[0082] The most preferred counterion is OH - is.

[0083] In step (3), the latex (I X When the contaminant / residue is contacted with the anion exchange resin, the resin beads generally adsorb or immobilize the undesired anions of the contaminants / residues on their positively charged ion exchange sites, and the original ions bound to the beads are released into the purified latex (I X ) can be found in

[0084] Anion exchange resins have OH groups fixed to their positively charged ion exchange sites. - When an anion is contained, the OH - The anions are ultimately present in the purified aqueous dispersion. X ) may undergo a noticeable pH increase. Depending on the foreseen use and in order to ensure that coagulation phenomena are avoided, pH adjustment may be necessary.

[0085] Step (3) may include contacting the latex (IX) with a cation exchange resin; step (3) may include such contact with the cation exchange resin before, after, or instead of contact with the anion exchange resin. Nevertheless, to thoroughly remove residues / contaminants and ensure that the ionizable groups are provided in the appropriate form, contact with the cation exchange resin occurs after contact with the anion exchange resin.

[0086] Non-limiting examples of negatively charged ion exchange sites on cation exchange resins suitable for use in the method of the present invention include the following: Illustrated in TIFF0007758781000008.tif31170.

[0087] The choice of cations to be fixed on the negatively charged ion exchange sites depends on the amount of cations that must be removed from the latex (I X The size of the exchange site is not critical, provided that the site typically has a lower affinity for the cations contained in the cation exchange resin. For example, cation exchange resins usually have sodium (Na + ) or hydrogen (H + ) ions. Both of these ions have a low affinity for these sites. Almost any cation that comes into contact with the cation exchange resin will have a greater affinity and will displace a hydrogen or sodium ion at the exchange site.

[0088] Cation exchange resins preferably accept hydrogen (H) on their negatively charged ion exchange sites. + ) ions are connected.

[0089] The cation exchange resin immobilizes H2O2 on its negatively charged ion exchange sites. + If it contains a cation, + The cations are finally deposited in a latex (I X ) and therefore H + Such contact with a cation exchange resin having cations may result in the formation of ionomers (I) in their acid forms, i.e., their -SO3H, -PO3H, and -COOH. X ) is effective in ensuring an ionizable group.

[0090] Therefore, latex (I X ) to hydrogen (H + When contacted with a cation exchange resin having cations, the latex (I X) will decrease in pH, which may require pH adjustment by known methods.

[0091] In step (4), the latex (I X ) is subjected to spray drying.

[0092] Spray drying is a well-known technique for converting a liquid volume / suspension into a dry powder by evaporating the liquid medium from droplets dispersed in a drying chamber and contacting a drying gas stream.

[0093] Therefore, step (4) of the method of the present invention is to x ), optionally after purification, is passed through a nozzle to generate droplets, and the droplets are dispersed in a drying chamber.

[0094] Any type of nozzle may be used, such as a pressure nozzle, among others, in which the droplet size can be adjusted based on the hole size and pressure; or a rotary atomizer in which the droplet size can be adjusted based on the diameter and rotation speed of the rotating element.

[0095] As regards the drying gas, in step (4) a stream of heated air can be advantageously used, although other gases, such as nitrogen, among others, may be equally effective.

[0096] The direction of the drying gas flow can be parallel or counter to the vertical downward droplet flow as achieved by gravity. A combination of parallel and counter drying gas flow can be preferred to optimize the size distribution of the material (P).

[0097] In step (4), the droplets of latex (Ix) are advantageously dried using a drying gas at a temperature such that the temperature in the drying chamber is at least 50°C, preferably at least 60°C, more preferably at least 80°C, and most preferably at least 85°C. XTo avoid coalescence of elementary particles of the granules, the temperature of the drying gas in step (4) is generally adjusted so that the temperature of the drying chamber is at most 125°C, preferably at most 120°C, more preferably at most 115°C. Ideally, a drying gas that maintains a drying chamber temperature of 90-110°C would be preferred.

[0098] The results of the process of the present invention are obtained by the production of ionomers (I X ), which is another object of the present invention.

[0099] The material (P) of the invention is composed of particles in the form of hollow agglomerates having an average particle size of between 1 and 150 μm; preferably, the average particle size of said particles is at least 3 μm, more preferably at least 5 μm and / or at most 100 μm, preferably at most 50 μm, even more preferably at most 40 μm.

[0100] Furthermore, the material (P) is composed of particles that are pseudo-spherical.

[0101] Pseudospherical, according to the present invention, means that the particles have a spherical or approximately spherical shape. Geometrically, a sphere is described by axes of equal length, starting from a common origin and pointing into space, which define the radius of the sphere in all spatial orientations. Spherical particles are therefore particles whose shape meets this geometric requirement. On the other hand, in pseudospherical particles, the length of the axes characterizing their shape can deviate from the ideal sphere by 1% to 40%. Preferably, pseudospherical particles are obtained with a deviation of no more than 25%, particularly preferably no more than 15%. The pseudospherical or spherical shape of a particle can be determined by image analysis of a suitable magnification obtained by microscopy, for example electron microscopy.

[0102] The particles are hollow agglomerates of elementary particles, and indeed their hollow character can be demonstrated using scanning electron microscopy, i.e., by taking magnified photographs of the hollow agglomerates before and after compression at sufficient pressure intensity, the collapse of the hollow agglomerates, which is evidence of their hollow character, can be readily demonstrated.

[0103] Image analysis of the microscopic magnification showed that the pseudo-spherical particles were indeed the same as the original latex from which they originated (I X ) indicates that it is a clump of elementary particles corresponding to the elementary particles of the

[0104] More particularly, the particles have a mean diameter of 15 to 150 nm; more particularly, the mean diameter is advantageously at least 30 nm, preferably at least 50 nm and / or advantageously at most 140 nm, preferably at most 120 nm, most preferably at most 100 nm.

[0105] The average diameter of the elementary particles can be determined by scanning electron microscopy followed by image analysis. Sections of the magnified image are inspected visually or computer-aided, and the elementary particles are counted. The counted particles are modeled as spheres with a diameter equal to the smallest diameter that provides a sphere that encloses the elementary particles. The average diameter is then determined as the arithmetic mean.

[0106] The ionomer (I) considered in the process of the present invention X All of the features disclosed above in relation to the ionomer (I) of the material (P) of the present invention are X ) is also a characteristic that applies to

[0107] The present invention further relates to a method for providing a coating composition, which method comprises the step of contacting a material (P) as detailed above with a liquid medium.

[0108] The liquid medium is not particularly limited; it is preferred that the liquid medium comprises water, and preferably comprises water as the main component, although organic solvents can be used. Small amounts of organic solvents, such as alcohols, especially aliphatic alcohols (generally including glycols or polyols), can be included in the liquid medium of the aqueous coating composition.

[0109] The coating compositions so obtained find utility for coating and / or impregnating a variety of substrates.

[0110] Therefore, a method of coating or impregnating a substrate comprising using a coating composition comprising a liquid medium and material (P) as detailed above remains within the scope of the present invention.

[0111] If the disclosure of any patent, patent application, or publication incorporated herein by reference contradicts the statement of this application to the extent that it may render a term unclear, the statement shall control.

[0112] The present invention will now be described in connection with the following examples, which are illustrative only and are not intended to limit the scope of the invention.

[0113] material: Preparative Example 1 - Preparation of TFE-VEFS polymer latex in -SO2F form In a 22 L autoclave, add the following reagents: - 9.3L of demineralized water; - 700 g of monomer (VEFS) of formula: CF2 = CF-O-CF2CF2-SO2F; - 650g of ClF2O(CF2CF(CF3)O) n (CF2O) m 5 wt% aqueous solution of CF2COOK (average molecular weight = 521, ratio n / m = 10) was loaded.

[0114] The autoclave, stirred at 470 rpm, was heated to 66°C. A 170 ml volume of 9 g / L aqueous solution of potassium persulfate was added. The pressure was maintained at 14.4 bar (absolute) by feeding tetrafluoroethylene (TFE). During the polymerization, aliquots of 100 g of VEFS were repeatedly added to the reactor for every 160 g of tetrafluoroethylene. The reaction was stopped after 240 min by interrupting the stirring, cooling the autoclave, and reducing the internal pressure by venting the TFE; the total mass of TFE fed to the reactor was 3200 g. The precursor latex thus obtained had a solids content of 30 wt%. A small sample of the latex thus obtained was then coagulated by freezing and thawing, and the recovered polymer was washed with water and dried at 80°C for 48 h. The equivalent weight (EW) of the corresponding polymer was determined to be 967 g / mol by FT-IR measurements. The polymer particles dispersed in the obtained latex were found to have a particle size of 50 to 100 nm.

[0115] Preparative Example 2 - Preparation of TFE-VEFS aqueous dispersion The precursor latex of Preparative Example 1 was coagulated by freezing and thawing, and the recovered powder was thoroughly washed with water and then dried at 80°C for 48 hours. First, a portion (100 g) of the precursor ionomer powder thus obtained was treated with a solution (1 L) of 14 wt. % potassium hydroxide, 30 wt. % dimethyl sulfoxide, and 56 wt. % demineralized water under stirring at 80°C for 8 hours. After several washes with demineralized water, the recovered solid polymer was acidified with 1 L of 20 wt. % nitric acid solution at room temperature for 2 hours. The powder thus obtained was washed again with demineralized water and finally dried in an oven at 80°C for 8 hours. Quantitative conversion of -SO2F to -SO3H functional groups was confirmed by FT-IR analysis. 60 g of the hydrolyzed ionomer powder was mixed with 160 g of demineralized water in a 250 ml titanium autoclave. The mixture was heated to a temperature above 180°C and stirred at 750 rpm. After 4 hours, the mixture was cooled and the aqueous dispersion was purified by centrifugation (10,000 rpm) for 2 hours. A clear and transparent dispersion of the ionomer had a solids content of 22.7% by weight.

[0116] Preparative Example 3 - Hydrolysis of TFE-VEFS Precursor Latex to Provide Ionomer Latex One liter of the precursor latex prepared in Preparative Example 1 was contacted with 73.5 g of a 2 wt% NaOH / H2O solution at room temperature for 5 days, followed by 73.5 g of a 20 wt% NaOH / H2O solution at room temperature for 2 days. The conversion of the intact -SO2F groups to -SO3Na was evaluated by solid-state nuclear magnetic resonance (NMR). The mixture was then treated in a purification column with Lewatit Monoplus M800 OH anion exchange resin as the stationary phase, followed by a final treatment in a column with Lewatit Monoplus S 108 H cation exchange column as the stationary phase. Complete conversion of the ionizable -SO3Na groups to -SO3H was confirmed by ICP-OES analysis. A purified latex of the ionomer with a solids content of 15 wt% was then recovered. The ionomer particles dispersed in the resulting latex were found to have a particle size of 50-100 nm.

[0117] Comparative Example 4 - Spray drying of TFE-VEFS dispersion from Example 2 The ionomer dispersion (200 g) prepared in Preparative Example 2, which had been subjected to solid-phase hydrolysis by redispersion of the previously coagulated ionomer precursor in water, was spray-dried in a spray dryer device with a heated air inlet temperature of about 190°C and a 0.7 mm diameter co-current twin-headed fluid nozzle, resulting in an average drying chamber temperature of about 100°C, to obtain a dry powder (about 44 g). Microscopic analysis showed that the particles of the resulting powder were spherical and had an average size of about 30 μm. The particles did not exhibit structure such as agglomerates of elementary particles. Rather, they were found to be continuous, uniform particles.

[0118] Example 5 - Spray drying of the ionomer latex from Example 3 The ionomer latex (200 g) prepared in Example 3 was spray-dried in a spray dryer device with a heated air inlet temperature of about 190°C and an integrated co-current twin-head nozzle with a diameter of 0.7 mm, resulting in an average drying chamber temperature of about 100°C, to obtain a dry powder (about 30 g). The particles of the resulting powder were spherical and had an average size of about 10 μm; the particles were found to be hollow. Furthermore, each particle was composed of smaller particles with an average diameter of about 80 nm and diameters ranging from about 60 to about 100 nm.

[0119] Redispersion of powders from Comparative Example 4 and Example 5 in water and viscosity measurements The powders obtained as described in Comparative Example 4 and Example 5 were dissolved in demineralized water at room temperature and under stirring to obtain two aqueous formulations with a solids content of 25% by weight.

[0120] In both cases, the powder was easily and quickly solubilized, with no measurable solid residue. The aqueous formulations were stirred for 100-1000 seconds. -1 Fluid viscosity measurements were performed at room temperature (23°C) using a viscometer in Couette geometry with a shear rate sweep of 100 s. The results are summarized in the table below.

[0121] TIFF0007758781000009.tif33170

[0122] The data compiled in the table above amply demonstrate that the method of the present invention provides inventive powders that are particularly capable of producing liquid formulations that are easily redispersible in aqueous media and have increased liquid viscosity, especially at low shear rates, making them compatible with typical coating techniques, without the need for the addition of thickeners or other viscosity enhancers that can generally impair the overall performance of the coated / impregnated articles obtained therefrom.

Claims

1. -SO ３ X ａ , -PO ３ X ａ and -COOX ａ (where X ａ at least one fluorinated ionomer [ionomer (I) Ｘ ) ) ] powder material [material (P)] consisting of a plurality of particles, the particles consist of pseudo-spherical hollow agglomerates of elementary particles; - the hollow agglomerates have an average particle size of between 1 μm and 150 μm; and a powdered material [material (P)], the particles of which have an average diameter between 15 nm and 150 nm.

2. Ionomer (I Ｘ ) contains repeating units derived from an ethylenically unsaturated monomer containing at least one fluorine atom, and / or an ionomer (I Ｘ ) comprises said ionizable group as a pendant group covalently bonded to a hydrolyzed repeat unit derived from a functional monomer (hereinafter monomer (X)), or ionomer (IX) is a copolymer comprising hydrolyzed repeat units derived from one or more monomers (X) and repeat units derived from one or more additional monomers different from monomer (X), wherein monomer (X) is a fluorinated monomer.

3. Ionomer (I Ｘ ) represents multiple -SO ３ X ａ Ionomers containing groups (I ＳＯ３Ｘ ) and ionomer (I ＳＯ３Ｘ ) is at least one -SO ３ X ａ group (wherein X ａ is H) and at least one —SO ２ X Ｘ group (wherein X Ｘ a plurality of hydrolyzed repeat units derived from at least one ethylenically unsaturated fluorinated monomer (hereinafter monomer (A)) containing —SO ２ X Ｘ and a plurality of repeat units derived from at least one ethylenically unsaturated fluorinated monomer (hereinafter referred to as monomer (B)) that does not contain a group.

4. The monomer (A) is - Formula: CF ２ =CF(CF ２ ) ｐ SO ２ X Ｘ (where X Ｘ is a halogen and p is 0-10; - Formula: CF ２ =CF-O-(CF ２ ) ｍ SO ２ X Ｘ (where X Ｘ is a halogen and m is 1 to 10; - Formula: CF ２ =CF-(OCF ２ CF (R Ｆ１ )) ｗ -O-CF ２ (CF(R Ｆ２ )) ｙ SO ２ X Ｘ (where X Ｘ is halogen; w is an integer from 0 to 2, and R Ｆ１ and R Ｆ２ is independently F, Cl, or C optionally substituted with one or more ether oxygens; １ ~C １０ a fluoroalkyl group, and y is an integer from 0 to 6; - Formula CF ２ =CF-Ar-SO ２ X Ｘ (where X Ｘ is a halogen, and Ar is C ５ ~C １５ sulfonyl halide aromatic fluoroolefins, and monomer (A) is selected from the group consisting of: ２ =CF-O-(CF ２ ) ｍ -SO ２ 4. The material (P) according to claim 3, wherein m is selected from the group of sulfonyl fluoride fluorovinyl ethers of formula F (where m is 1 to 6).

5. The monomer (B) is - C ２ ~C ８ perfluoroolefin; - C ２ ~C ８ hydrogen-containing fluoroolefins; - C ２ ~C ８ chloro-, and / or bromo-, and / or iodo-containing fluoroolefins; - Formula CF ２ =CFOR ｆ１ (where R ｆ１ is C １ ~C ６ fluoroalkyl vinyl ethers, -Formula CF ２ = CFOCF ２ OR ｆ２ (where R ｆ２ is C １ ~C ３ fluoro(oxy)alkyl groups, including fluoromethoxyalkyl vinyl ethers of the formula CF ２ =CFOX ０ (where X ０ is a C containing one or more ether oxygen atoms １ ~C １２ fluorooxyalkyl vinyl ethers, wherein the fluorooxyalkyl group is a fluorooxyalkyl group; - Formula: (wherein R ｆ３ , R ｆ４ , R ｆ５ , R ｆ６ Each of the groups independently comprises a C optionally containing a fluorine atom, one or more oxygen atoms. １ ~C ６ fluoro(halo)fluoroalkyl) Fluorodioxole and monomer (B) is selected from the group consisting of: C selected from tetrafluoroethylene (TFE) and / or hexafluoropropylene (HFP) ２ ~C ８ perfluoroolefin; C selected from trifluoroethylene (TrFE), vinylidene fluoride (VDF) and vinyl fluoride (VF) ２ ~C ８ hydrogen-containing fluoroolefins; and - their mixtures 5. The material (P) according to claim 3 or 4, selected from the group consisting of:

6. At least one monomer (B) is tetrafluoroethylene (TFE) and an ionomer (I ＴＦＥ ＳＯ３Ｘ )teeth, (1) A repeating unit derived from tetrafluoroethylene (TFE), which is an ionomer (I ＴＦＥ ＳＯ３Ｘ ) in an amount of 50 to 99 mol % based on the total moles of repeat units; (2) at least one -SO ３ X ａ group, and (j) Formula: CF ２ =CF-O-(CF ２ ) ｍ SO ２ X Ｘ (where X Ｘ is a halogen; and m is an integer from 1 to 10; (jj) Formula: CF ２ =CF-(OCF ２ CF (R Ｆ１ )) ｗ -O-CF ２ (CF(R Ｆ２ )) ｙ SO ２ X Ｘ (where X Ｘ is halogen; w is an integer from 0 to 2, and R Ｆ１ and R Ｆ２ is independently F, Cl, or C optionally substituted with one or more ether oxygens; １ ~C １０ and y is an integer from 0 to 6; and (jjj) A mixture of these and a hydrolyzed repeating unit derived from at least one monomer selected from the group consisting of an ionomer (I ＴＦＥ ＳＯ３Ｘ ) in an amount of 1 to 50 mole % hydrolyzed repeat units based on the total moles of repeat units; (3) optionally hexafluoropropylene, formula CF ２ =CFOR' ｆ１ (where R' ｆ１ is C １ ~C ６ perfluoroalkyl vinyl ethers of the formula CF ２ = CFOCF ２ OR' ｆ２ (where R' ｆ２ is C １ ~C ６ C which is perfluoroalkyl or has one or more ether groups １ ~C ６ perfluoroalkyl-methoxy-vinyl ethers of the formula CF ２ =CFOR' Ｏ１ (where R' Ｏ１ is a C having one or more ether groups ２ ~C １２ a repeating unit derived from at least one hydrogen-containing monomer selected from the group consisting of perfluoro-oxyalkyl vinyl ethers of perfluoro-oxyalkyl (I) and / or a fluorinated monomer different from TFE, ＴＦＥ ＳＯ３Ｘ ) repeating units in an amount of 0 to 45 mol % based on the total moles of repeating units; selected from a polymer consisting essentially of: Ionomer (I ＴＦＥ ＳＯ３Ｘ ) is the ionomer (I ＴＦＥ ＳＯ３Ｘ ) based on the total moles of repeating units of (k) 55 to 95 mol % of repeating units derived from TFE; (kk) 5 to 45 mol % of at least one —SO ３ X ａ a hydrolyzed repeat unit derived from monomer (2) containing a group and as detailed above; (3) 0 to 25 mol % of repeating units derived from fluorinated monomer (3) other than TFE as detailed above 6. The material (P) according to claim 5, consisting essentially of

7. At least one monomer (B) is vinylidene fluoride (VDF) and an ionomer (I ＶＤＦ ＳＯ３Ｘ )teeth, (1) A repeating unit derived from vinylidene fluoride (VDF), which is an ionomer (I ＶＤＦ ＳＯ３Ｘ ) in an amount of 55 to 99 mole % based on the total moles of repeat units; (2) at least one -SO ３ X ａ group, and (j) Formula: CF ２ =CF-O-(CF ２ ) ｍ SO ２ X Ｘ (where X Ｘ is a halogen and m is an integer from 1 to 10; (jj) Formula: CF ２ =CF-(OCF ２ CF (R Ｆ１ )) ｗ -O-CF ２ (CF(R Ｆ２ )) ｙ SO ２ X Ｘ (where X Ｘ is a halogen, w is an integer from 0 to 2, and R Ｆ１ and R Ｆ２ is independently F, Cl, or C optionally substituted with one or more ether oxygens; １ ~C １０ and y is an integer from 0 to 6; and (jjj) A mixture of these and a hydrolyzed repeating unit derived from at least one monomer selected from the group consisting of an ionomer (I ＶＤＦ ＳＯ３Ｘ ) in an amount of 1 to 45 mole % hydrolyzed repeat units based on the total moles of repeat units; (3) Optionally, repeating units derived from at least one hydrogen-containing monomer or fluorinated monomer other than VDF, which are ionomers (I ＶＤＦ ＳＯ３Ｘ ) repeating units in an amount of 0 to 30 mol % based on the total moles of repeating units; selected from a polymer consisting essentially of: Ionomer (I ＶＤＦ ＳＯ３Ｘ ) is the ionomer (I ＶＤＦ ＳＯ３Ｘ ) based on the total moles of repeating units of (1) 55 to 95 mol % of repeating units derived from VDF; (2) 5 to 40 mol % of at least one —SO ３ X ａ a hydrolyzed repeat unit derived from at least one monomer (2) comprising a group and as detailed above; (3) 0 to 15 mol % of repeating units derived from a hydrogen-containing monomer or a fluorinated monomer other than VDF (3) as detailed above.

6. The material (P) according to claim 5, which is a polymer consisting essentially of:

8. Ionomer (I Ｘ The amount of ionizable groups in the ionomer (I Ｘ 8. The material (P) according to claim 1, wherein the total weight of the material (P) is at least 0.55 meq / g and / or at most 3.50 meq / g.

9. Material (P) according to any one of claims 1 to 8, which is composed of particles consisting of hollow agglomerates with an average particle size of at least 3 μm and / or at most 100 μm.

10. 10. A material (P) according to any one of claims 1 to 9, which is composed of particles consisting of agglomerates of elementary particles having an average diameter of at least 30 nm and / or at most 140 nm.

11. The material (P) according to any one of claims 1 to 10, wherein the pseudo-spherical particles are such that the length of an axis characterizing the shape of said pseudo-spherical particles deviates from an ideal sphere by 1% to 40%.

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