Copolymers of fluorinated olefins and functional vinyl esters

Abstract

Copolymers comprising, in polymerized form, one or more fluorinated olefins and one or more functional vinyl esters are disclosed.

Description

COPOLYMERS OF FLUORINATED OLEFINS AND FUNCTIONAL VINYLESTERSField of the Invention

[0001] The invention relates to copolymers made from fluorinated olefins and one or more functional vinyl esters, methods for making such copolymers and products comprising such copolymers.Background of the Invention

[0002] Fluoropolymers are traditionally used for applications requiring special properties, such as low surface energy, high resistance to chemical attack, environmental aging resistance, and electrochemical stability. However, this inertness also can make fluoropolymers difficult to work with and limit their applications. The lack of functional groups on fluoropolymers makes them difficult to adhere to substrates, to facilitate cross-linking, to provide sites for subsequent chemical modification, to be wetted by water, and to add hydrophilic characteristics. There is a need for fluorinated polymers having modified structure, such as bearing functional groups, which can augment their properties.

[0003] It is difficult to add functional monomer units directly by traditional copolymerization into the fluoropolymer, due to the aggressive nature of the fluorine-containing free radicals. Nonetheless, functionality has been added by other means, such as using a post-polymerization grafting mechanism, such as the grafting of maleic anhydride onto a polyvinylidene fluoride homopolymer or copolymer, as described in US 7,241,817. WO 2013 / 110740 and US 7,351,498 further describe functionalization of a fluoropolymer by monomer grafting or by copolymerization. Several examples disclose the copolymerization of fluoromonomer with a non-fluorinated, functional comonomer.

[0004] US 5,415,958, discloses copolymerization of vinylidene fluoride with an unsaturated dibasic acid monoester polar monomer, to introduce carbonyl groups to the backbone of PVDF to improve its adhesion to different substrates.

[0005] US 8,337,725 discloses copolymerization of vinylidene fluoride with at least one hydrophilic (meth)acrylic monomer.

[0006] US 10,570,231 B2 discloses a process for copolymerization of vinylidene fluoride with non-functional vinyl ester monomers.

[0007] There is a need to further improve the adhesion performance of fluorinated polymers in fdms, coatings or as binder in lithium-ion battery electrodes.

[0008] It is difficult to get a high degree of functionalization in a fluoropolymer by direct copolymerization of fluoromonomer with non-fluorinated, functionalized comonomer. Attempts to incorporate non-fluorinated, functionalized comonomer during copolymerization leads to reduction of polymerization rate and decrease of product molecular weight, which are detrimental to productivity and final application properties, respectively.

[0009] It has been found that non-fluorinated, functional comonomers bearing a vinyl ester polymerizable group (“functional vinyl ester comonomer”) can be incorporated into a fluoropolymer. Additionally, addition of the functional vinyl ester comonomer to an aqueous emulsion or suspension polymerization of fluoromonomer results in limited reduction in polymerization rate and produces high molecular weight product. The introduction of the functional vinyl ester comonomer into the copolymer imparts functional groups to improve the final performance of the material in applications such as binder for lithium-ion batteries.Brief Summary of the Invention

[0010] The present invention provides copolymers and copolymer compositions obtained by copolymerization of one or more fluorinated olefins with one or more functional vinyl ester comonomers. Accordingly, the present invention provides copolymers comprising, consisting essentially of, or consisting of, in polymerized form, at least one fluorinated olefin, preferably vinylidene fluoride, and at least one functional vinyl ester comonomer. The present invention also provides for copolymer compositions comprising or consisting essentially of, in polymerized form, at least one fluorinated olefin, preferably vinylidene fluoride, and at least one functional vinyl ester comonomer.Detailed Description of Certain Embodiments of the Invention

[0011] The copolymers of the present invention comprise, in polymerized form, at least one fluorinated olefin with at least one functional vinyl ester comonomer, preferably the fluorinated olefin comprises or consists of vinylidene fluoride. Another object of this invention is to provide a polymeric composition comprising the inventive copolymer. Another object of this invention is to provide a method for preparing polymeric compositions having improved properties.

[0012] The copolymer of the present invention contains, in polymerized form, at least one fluorinated olefin. Suitable fluorinated olefins include organic compounds containing a carboncarbon double bond (C=C) and at least one fluorine atom. One or both carbon atoms of the carbon-carbon double bond may be substituted with one or more fluorine or chlorine atoms. Where the fluorinated olefin is comprised of three or more carbon atoms, one or more of the carbon atoms which are not part of the carbon-carbon double bond may also be substituted with one or more fluorine atoms. In this case, fluorine atoms may be present on at least one carbon atom of the carbon-carbon double bond and may be present on at least one carbon atom other than the carbon atoms of the carbon-carbon double bonds. In certain embodiments of the invention, the fluorinated olefin does not contain any elements other than carbon, fluorine and, optionally, hydrogen. The fluorinated olefin does not contain any aromatic moieties.

[0013] Suitable fluorinated olefins include olefins containing one, two, three or more fluorine (F) atoms. The fluorine atom(s) may be substituted on one or both carbon atoms involved in the carbon-carbon double bond and / or may be present as a substituent on a moiety, such as an alkyl group, that is attached to one or both carbon atoms involved in the carbon-carbon double bond. As used herein, the term “fluorinated olefin” refers to an organic compound containing at least one carbon-carbon double bond and at least one fluorine atom (and optionally one or more halogen atoms other than fluorine).

[0014] According to certain aspects of the invention, the fluorinated olefin may have a structure in accordance with formula (1):CX1X2=CX3X4(Formula 1) wherein X1, X2, and X3are independently selected from the group consisting of hydrogen (H), chlorine (Cl), fluorine (F), and fluorinated and non-fluorinated Cl -Cl 6 alkyl groups, preferably 1 to 8 carbon atoms: X4can be independently selected from the group consisting of hydrogen (H), chlorine (Cl), fluorine (F), fluorinated and non-fluorinated Cl -Cl 6 alkyl groups, preferably 1 to 8 carbon atoms, and fluorinated and non-fluorinated Cl -Cl 6 alkyl ether groups; preferably 1 to 8 carbon atoms; subject to the proviso that the fluorinated olefin comprises at least one fluorine atom. Any of the fluorinated alkyl groups or fluorinated alkyl ether groups may be partially or fully fluorinated (perfluorinated).

[0015] Specific representative examples of fluorinated olefins suitable for use in the present invention include, but are not limited to: vinylidene fluoride (VDF), tetrafluoroethylene (TFE), tri fluoroethylene (TrFE), chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), vinyl fluoride (VF), hexafluoroisobutylene (HFIB), perfluorobutylethylene (PFBE), pentafluoropropene, 3,3,3-trifluoro-l-propene, 2-trifluoromethyl-3,3,3-trifluoropropene, 2, 3,3,3- tetrafluoropropene, fluorinated vinyl ethers including perfluoromethyl ether (PMVE), perfluoroethylvinyl ether (PEVE), perfluoropropylvinyl ether (PPVE), perfluorobutylvinyl ether (PBVE), longer alkyl chain fluorinated or perfluorinated vinyl ethers, or partially- or perfluorinated alpha olefins of C4 and higher, and combinations thereof. In a preferred example of the invention, the fluorinated olefin comprises vinylidene fluoride (VDF).

[0016] The copolymer of the present invention also contains, in polymerized form, at least one functional vinyl ester comonomer.

[0017] Functional vinyl ester comonomer means, in the present invention, an unsaturated organic compound comprised of an ethylenically unsaturated moiety (meaning a carbon-carbon double bond), having an ester group substituted on a carbon of the carbon-carbon double bond, said moiety may be generally represented as -C=C-O-(CO)-R- wherein R is a bond, or an organic group with a molecular weight of not more than 500 containing carbon, hydrogen, and may optionally comprise at least one heteroatom selected from oxygen atom or nitrogen atom. In one embodiment, the organic group has a main chain comprising from 1 to 16 carbon atoms, and is preferably an alkyl, alkyl ether or substituted alkyl linking group. The functional vinyl ester moiety also contains a functional group which may be generally represented as ‘A’ in the general representation: -C=C-O-(CO)-R-A. Functional group A is selected from an acid, acid salt or alkyl ester group. In the case where R is a bond, then A is carboxylic acid or salt thereof. In some embodiments A is selected from carboxylic acid or salt or alkyl ester group thereof, sulfonic acid or salt or alkyl ester group thereof, phosphonic acid or salt or alkyl ester group thereof.

[0018] A generalized structure for the functional vinyl ester comonomer (2) is shown below. The functional vinyl ester comonomer includes an ethylenic unsaturation (with Ri, R2 and R3), an ester group, a linking group (R4) and a functional group AL Suitable functional vinyl esters may include compounds corresponding to structural formula (2):Ri, R2 and R3 are independently selected from a hydrogen atom, a chlorine atom, or nonfluorinated alkyl group; in the case of an alkyl group, preferably the alkyl group comprises from 1 to 8 carbon atoms. R4 is selected from a bond, an organic group with a molecular weight of not more than 500 containing carbon, hydrogen and optionally at least one heteroatom selected from oxygen atom, nitrogen atom, and having a main chain comprising from 1 to 16 carbon atoms. Preferably R4 is a Cl -Cl 6 hydrocarbon group and may optionally contain non-carbon-carbon bond linkages selected from ether, ester, amide, amine, urethane, urea, imine, imide, and may optionally contain one or more pendent heteroatom-containing groups selected from a ketone, epoxide, alcohol, and amine group.R4 can be a bond, Cl -Cl 6 hydrocarbon (including alkyl, cycloalkyl, or aryl) group which may contain additional non-carbon-carbon bond linkages such as ether, ester, amine, or amide. R4 may also contain one or more pendent heteroatom-containing groups on the Cl -Cl 6 hydrocarbon, such as ketone, epoxide, alcohol, amine and the like.

[0019] In some embodiments, R4 is a bond, or an alkyl group having from 1 to 12 carbon atoms, and may contain ether or ester linkages.

[0020] In all embodiments where R4 is a bond, then Ai is carboxylic acid or salt thereof.

[0021] Ai is an acid, acid salt or alkyl ester group. Ai may be selected from carboxylic acid, alkali metal carboxylate salt, ammonium carboxylate salt, alkylammonium carboxylate salt, sulfonic acid, alkali metal sulfonate salt, ammonium sulfonate salt, alkylammonium sulfonate salt, phosphonic acid, alkali metal phosphonate salt, ammonium phosphonate salt, alkylammonium phosphonate salt Examples of Ai include, but are not limited to carboxylic acid (C(O)OH), alkali metal carboxylate salt (COO-M+), ammonium carboxylate salt (COO-NH4+), alkylammonium carboxylate salt (COO-N(R)4+), sulfonic acid (S(O)(O)OH), alkali metal sulfonate salt (S(O)(O)O-M+), ammonium sulfonate salt (S(O)(O)O-NH4+), alkylammonium sulfonate salt (S(O)(O)O-N(R)4+), phosphonic acid (P(O)(OH)2), monoalkali metal phosphonate salt (P(O)(OH)(O-M+), dialkali metal phosphonate salt (P(0)(0-M+)2), monoammonium phosphonate salt (P(O)(OH)(O-NH4+), diammonium phosphonate salt (P(O)(O-NH4+)2), monoalkylammonium phosphonate salt (P(O)(OH)(O-N(R)4+), or dialkylammonium phosphonatesalt (P(O)(O-(R)4+)2); in these Examples of Ai R is an alkyl group having between 1 and 12 carbon atoms and M+ represents a metal anion.

[0022] Preferably, Ai is an acid, acid salt or alkyl ester group. Preferably, Ai comprises carboxylic acid group, phosphonic acid group, sulfonic acid group or any of their salts with alkali metals, alkaline earth metals or organic positively charged counterions, such as ammonium, alkyl ammonium and tetraalkyl ammonium. In the case of Ai being an alkyl ester group, the alkyl moiety comprises 1 to 12 carbon atoms.

[0023] Preferred embodiments of structural formula (2): include whereRi , R2 and R3, each independently, may be H, Cl, C2, C3, C4, C5, C6, C7, or C8 alkyl group; a C3, C4, C5, C6, C7, C8 branched alkyl group, and R4 may be a bond, or a Cl, C2, C3, C4, C5, C6, C7, C8, C9, CIO, Cl l, C12, C13, C14, C15 or C16 alkyl group; a C3, C4, C5, C6, C7, C8, C9, CIO, Cl l, C12, C13, C14, C15 or C16, branched alkyl group; a C3, C4, C5, C6, C7, C8, C9, CIO, Cl l, C12, C13, C14, C15 or C16 cycloalkyl group. For cycloalkyl, the most preferred is cyclohexyl. R4 may contain additional non-carbon-carbon -bond linkages between carbon atoms of the C2 to C16 alkyl, branched alkyl or cycloalkyl groups, such as ether, ester, amine, or amide linkages. R4 may also contain one or more pendent heteroatom -containing groups such as ketone, epoxide, alcohol, amine and the like; and Ai is carboxylic acid, phosphonic acid, sulfonic acid, or the alkali metal salts thereof (such as lithium, sodium, potassium, rubidium, or cesium).

[0024] In the case of phosphonic acid where two or more acidic hydrogens are present, they may both remain as hydrogen, or one neutralized as alkali metal salt or both as alkali metal salts. Additional salt forms are also contemplated such as higher valent salts such as alkaline earth metals (beryllium, magnesium, calcium, strontium and barium). In the case of di- or multi-valent cations, more than one molecule of (2) may be present such that the total ionic charge between molecules (2) and the di- or multi-valent counterion is zero. Additionally, organic counterions are contemplated such as: ammonium, alkyl trihydrogen ammonium, dialkyl dihydrogen ammonium, trialkyl hydrogen ammonium and tetraalkyl ammonium.

[0025] In a preferred embodiment, the functional vinyl ester comonomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 is comprises a C3, alkyl group and Ai is a carboxylic acid or salt form.

[0026] In a preferred embodiment, the functional vinyl ester comonomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 comprises a C4 alkyl group and Ai is a carboxylic acid or salt form.

[0027] In a preferred embodiment, the functional vinyl ester comonomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 comprises a C5 alkyl group and Ai is a carboxylic acid or salt form.

[0028] In a preferred embodiment, the functional vinyl ester comonomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 comprises a C6 alkyl group and Ai is a carboxylic acid or salt form.

[0029] The functional vinyl ester may have a molecular weight of less than 900 g / mol, or less than 800 g / mol or less than 700 g / mol. It may be measured measured by GCMS (gas chromatography / mass spectroscopy) or calculated based on structure of the monomer.

[0030] As used herein, the term "alkyl" is defined to include saturated aliphatic hydrocarbons including straight (linear) chains and branched chains. In some embodiments, the alkyl group has 1 to 16 carbon atoms, from 1 to 10 carbon atoms, from 1 to 6 carbon atoms, or from 1 to 4 carbon atoms. An alkyl group optionally can be substituted by one or more (e.g. 1 to 5) suitable substituents. Heteroatoms such as oxygen, phosphorus and nitrogen may be present in the alkyl group, to provide a heteroalkyl group. Non limiting illustrative examples of heteroalkyl groups include CH2CH2N(CH3)2 and CH2CH2OCH2CH3.

[0031] As used herein, the term "cycloalkyl" refers to saturated or unsaturated, non-aromatic, monocyclic hydrocarbon rings (e.g., monocyclics such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or cyclononyl). The cycloalkyl group may have 3 to 16 carbon atoms. The cycloalkyl group optionally can be substituted by 1 or more (e.g., 1 to 5) suitable substituents.

[0032] Suitable types of groups which may be present as substituents in any of the above- mentioned organic moieties include one or more of the following: chlorine, alkyl, ether, hydroxyl, ketone, amide, or amine.

[0033] As used herein, the term "optionally substituted" means that substitution is non- compulsory and therefore includes both unsubstituted and substituted atoms and moieties. A "substituted" atom or moiety indicates that any hydrogen on the designated atom or moiety can be replaced with a selection from the indicated substituent group (up to that every hydrogen atom on the designated atom or moiety is replaced with a selection from the indicated substituent group), provided that the valency of the designated atom or moiety is not exceeded, and that the substitution results in a stable compound. For example, if an ethyl group (i.e., -C2H5) is optionally substituted, then up to five hydrogen atoms on the phenyl ring can be replaced with substituent groups.

[0034] The fluorinated copolymer of the invention or inventive composition may comprise from 0.01% up to 50.0wt% of functional vinyl ester monomer units. The fluorinated copolymer of the invention may comprise from 50.0% to 99.99% by weight fluorinated olefin and from 50.0% to 0.01% by weight functional vinyl ester in polymerized form. In some embodiments, fluorinated copolymer of the invention may comprise from 75.0% to 99.99% by weight fluorinated olefin and from 25.0% to 0.01% by weight functional vinyl ester in polymerized form. In some embodiments fluorinated copolymer of the invention may comprise from 95.0% to 99.95% by weight fluorinated olefin and from 5.0% to 0.05% by weight functional vinyl ester in polymerized form.

[0035] The copolymer of the present invention may also contain other ethylenically unsaturated comonomers besides the fluorinated olefin(s) and the functional vinyl ester comonomer(s). In certain embodiments, the copolymer does not contain any monomer other than fluorinated olefin and functional vinyl ester comonomer. In other embodiments, however, the copolymer comprises up to 20%, up to 10%, up to 5% or up to 1% by weight of one or more monomers other than fluorinated olefin and functional vinyl ester comonomer. The fluorinated copolymer of the invention may comprise at least 50 % by weight fluorinated olefin and at least 0.01% by weight functional vinyl ester in polymerized form and preferably at least 0.1% by weight functional vinyl ester in polymerized form.

[0036] A preferred arrangement of the monomers along the copolymer backbone is that of a random copolymer. By random copolymer, as is known in the art, is one in which the monomer residues are located in a statistically-random fashion in the polymer molecule. The random copolymer may have a linear structure, but in other embodiments may be of a branched architecture

[0037] The copolymers of the invention have a melt viscosity in the range of from 1 to 80kP, preferably 20 to 75kP more preferably 30 to 65 kP. Melt viscosity is measured in accordance with ASTM D3835 at 232°C expressed in kilopoise (kP) @ 100s1.

[0038] For many embodiments of the current invention, the copolymer is soluble in polar aprotic solvents such as N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N- dimethylacetaminde (DMAc), dimethylsulfoxide (DMSO), hexamethylphosphoramide (HMPA), triethylphosphate (TEP) and the like. Viscosity of a solution of the copolymer in the polar aprotic solvent at a concentration of 6.0 wt.% copolymer in solvent is measured according to method ASTM D5225-17 at 25C. The measured viscosity of the 6.0wt.% solution of copolymer in N- methylpyrrolidone (NMP), is from lOOcP to 20,000cP, preferably from 500cP to 10,000cP, and more preferably from 500cP to 5000cP.

[0039] The architecture of the copolymer is known to affect the final properties of the copolymer and variations are contemplated. Herein, the term “linear” is used per the well -understood definition in the art of a polymer chain bearing a single chain structure and only two end-groups. (Page 3 in R.J. Young and P. A. Lovell, Introduction to Polymers, Second Ed., London, 1991.) In this case, the polymer chain comprises only the prescribed (co)monomer units and is devoid of any other architectural variance such as additional, bonded chains (“branches”) of any length or number.

[0040] ‘ ‘Non-Linear” is used per the well-understood definition in the art of a polymer chain bearing one or more additional polymer chains bonded to the primary, linear polymer chain at “branch points”. (Page 3 and Page 4 in R.J. Young and P. A. Lovell, Introduction to Polymers, Second Ed., London, 1991.) The additional polymer chain(s) may be of any length from two monomer units to a plurality of monomer units. Monomer units comprising a branch may be the same as, or different-from, those in the main, linear chain, but generally are derived of the same monomer units present in the main chain. Branches may, themselves, may bear additional branches with these additional branches as described previously in terms of number of monomer units and composition.

[0041] ‘ ‘Branch points” is used per the well-understood definition in the art of a polymer backbone atomic unit whereby the first monomer unit comprising a branch is bound. For fluorinated ethylenic type polymers, this branch point is often a backbone carbon atom.

[0042] Some special cases of “branching” with “branch points” are known, such as “star”, “graft”, “comb”, “brush”, “chimera”, “hyperbranched”, and “dendrimer” structures. (N. Hadji christi dis, et.al, Chem. Rev. 2001, 101, 3747-3792) All of these architectural variants are contemplated and included in the definition of “non-linear” as it pertains to variations on “branching” structure. As described above, the compositions of the branch chains in these special cases may be of the same or different monomer composition, as well may contain monomer units in a block, random or gradient configuration.

[0043] In the present invention, the copolymer may have a linear or non-linear architecture.

[0044] In the present invention, combinations of fluoropolymer products containing the functional vinyl ester comonomer in different amounts is contemplated including fluoropolymer containing zero functional vinyl ester comonomer in combination with that containing a non-zero quantity of functional vinyl ester comonomer. Heterogeneous polymers are contemplated as part of the invention. As known in the art, the quantities of each material in such a combination can be determined by adsorption from solution as described in US 11,024,852 B2.

[0045] In the present invention, blends of the fluoropolymer products with other fluoropolymers as well as non-fluorinated polymers is contemplated.

[0046] In the present invention, the fluoropolymer can be produced as a plurality of nanoparticles in aqueous emulsion (“emulsion” or “latex”). Number average particle diameter of the nanoparticles is from Inm to lOOOnm. Preferably from 50nm to 500nm, most preferably from lOOnm to 400nm as measured by dynamic light scattering.

[0047] In the present invention, the fluoropolymer can be produced as a plurality of particles in aqueous suspension (“suspension”) by suspension polymerization. Number average diameter of the particles is from 10pm to 1000pm, preferably from 50pm to 750pm, more preferably from 50pm to 600pm. As measured by optical or electron microscopy.POLYMERIZATION:

[0048] In preferred embodiments, a copolymer in accordance with the present invention is formed by copolymerization of one or more fluorinated olefins and one or more functional vinyl ester comonomers.

[0049] The polymerization process can be a batch, semi-batch or continuous polymerization process. An emulsion process is preferred, though a suspension process or a solution process may also be used.

[0050] According to one preferred embodiment the medium acts as a solvent and / or dispersant for the monomer and / or polymer, and such operations include dispersion, emulsion and solution polymerization.

[0051] When the polymerization is conducted in an aqueous media, such as in a dispersion or an emulsion polymerization, the following procedure may be followed: to a reactor is initially added deionized water and at least one dispersion agent, followed by deoxygenation (removal of oxygen). The reactor may be a pressurized polymerization reactor equipped with a stirrer and heat control means. The stirring may be constant or may be varied to optimize process conditions during the polymerization. After the reactor reaches the desired temperature, at least one monomer is added to the reactor to reach a predetermined pressure and then a free radical initiator is introduced to the reactor with a suitable flow rate to maintain proper polymerization rate. The ratio of fluorinated olefin(s) and comonomer(s) may be selected at the beginning of the reaction stage, the middle of the reaction stage and in the finished reaction stage. The purpose of such selection (where the goal is to prepare a random copolymer) is to control the distribution of the different monomers to maximize the randomness of the copolymer formed, by favoring a statistically random distribution of monomers in the growing copolymer chain. After reaching the desired preset monomer quantity added, the feed of the monomers can be stopped. However, the charging of initiator can be stopped or continued to consume the unreacted monomers. After the initiator charging is stopped, the reactor may be cooled and agitation stopped. The unreacted monomers can be vented, and the prepared copolymer can be collected through a drain port or by other collection means. The copolymer can be isolated, if desired, using standard methods such as oven drying, spray drying, freeze drying, shear, salt or acid coagulation followed by drying, or kept in the aqueous media for subsequent application or use.

[0052] In an emulsion polymerization, a suitable surfactant or emulsifier can be employed to obtain a stable dispersion, thereby forming a plurality of copolymer particles in water (latex) of the copolymer. A surfactant is a type of molecule which has both hydrophobic and hydrophilic portions, which allows it to stabilize and disperse hydrophobic molecules and aggregates of hydrophobic molecules in aqueous systems such as a copolymer latex. Surfactants could includefluorinated or perfluorinated moi eties, but it is preferred to instead use one or more nonfluorinated surfactants, or optionally no surfactant.

[0053] A non-fluorinated surfactant is a surfactant in which there is no fluorine present in the surfactant. Suitable non-fluorinated surfactants are known in the art see for example US8080621, US8158734, US8338518, US8765890, and / or US9068071. Examples include, but not limited to, non-ionic block copolymers comprising blocks of polyethylene oxide and / or blocks of polypropylene oxide and or polybutylene oxide; alkyl phosphonic acids, alkyl carboxylic acids, polyvinylphosphonic acid, polyacrylic acid, polyvinyl sulfonic acid, and the salts thereof; alkanesulfonates; and alkyl sulfate surfactants.

[0054] The polymerization may use, for example, from 100 ppm to 2 weight percent, preferably 300 ppm to 1 weight percent, based on the weight of the copolymer solids, of one type of surfactant, or blends of surfactants. In the polymerization process, the surfactant or emulsifier may all be added at once prior to polymerization, fed continuously during the polymerization, fed partly before and then during polymerization, or fed after polymerization started and progressed for a while. Preferably there is no fluorinated or perfluorinated surfactant used. In one embodiment, no surfactant is used.

[0055] In suspension polymerization, dispersant or suspending agents are used in the polymerization process. Generally, any suspending agent previously or conventionally employed in polymerization processes for ethylenically unsaturated monomers may be used, as long as it remains undecomposed at the polymerization temperature. Suspending agents such as carboxymethyl cellulose or hydroxyalkyl cellulose or poly(vinyl alcohol) can be used in the process, for instance, at concentrations ranging from 0.0001 to 1.0 %, based on weight of the monomer charge.

[0056] The reaction can be started and maintained by the addition of any suitable initiator known for the polymerization of ethylenically unsaturated monomers including inorganic peroxides, organic peroxides and “redox” combinations of oxidizing and reducing agents. Examples of typical inorganic peroxides includes sodium, potassium or ammonium persulfate, which have useful activity in the 65°C to 105°C temperature range. Organic peroxides known in the art can be used for the polymerization. “Redox” systems can operate at even lower temperatures.Examples of redox systems include combinations of oxidants such as hydrogen peroxide, t-butylhydroperoxide, cumene hydroperoxide, or persulfate, with reductants such as reduced metal salts, iron (II) salts being a particular example, optionally combined with activators such as sodium formaldehyde sulfoxylate or ascorbic acid. Preferably the initiator used is a thermal initiator meaning there is no reductant used. When the terms “thermal initiator” or “thermal initiation system” is used, it does not include a redox system.

[0057] The total amount of initiator used is generally from 0.01% to 5.0% by weight on the total monomer weight used. A mixture of one or more organic initiators as described above and one of more inorganic radical initiators as defined above, can be used to conduct the polymerization at a desirable rate. Typically, sufficient initiator is added at the beginning to start the reaction, and then additional initiator may be optionally added to maintain the polymerization at a convenient or desired rate.

[0058] Other typical additives used in the emulsion polymerization of unsaturated fluoromonomers may be added at typical levels. Chain transfer agents are typically small molecules such as ethyl acetate or propane and may be added to the polymerization to regulate the molecular weight of the copolymer product. Any chain transfer agent known in the art useful with fluorinated polymerization reactions can be used. They can be added to a polymerization in a single portion at the beginning of the reaction, or incrementally or continuously throughout the reaction. The amount of chain-transfer agent depends on the activity of the chain transfer agent, the monomer nature and activity, and on the desired molecular weight of copolymer product, with a range from 0.01 to 2 weight percent based on the total weight of monomer added to the reaction mixture being typical.

[0059] Other additives which may be present during an aqueous media polymerization also include, but are not limited to paraffin antifoulants, buffering agents and other additives typically used in polymerizations with unsaturated monomers.

[0060] The temperature of the polymerization can vary depending on the characteristics of the initiator used, but it is typically between about 10° and 160° C, and most conveniently it is between 20° and 120° C or between 40° and 130° C, and most preferably from 60° and 120° C. The pressure of the polymerization is typically between 280 and 20,000 kPa, depending on the capabilities of the reaction equipment, the initiator system chosen, and the monomer selection. The polymerization pressure can be between about 2000 and 20,000 kPa. The polymerization pressure is preferably between 2,000 and 11,000 kPa, and most preferably from 2750-8000 kPa.

[0061] The inventive copolymer of the invention may be used as a binder in battery applications including but not limited to lithium-ion batteries. The inventive polymer may be used as a binder in an anode or cathode. The inventive copolymer may be used in or as a coating for a separator in a battery.

[0062] Said inventive copolymer according to the present invention or said inventive composition according to the present invention can be used in various applications. Thus, said inventive copolymer according to the present invention or said inventive composition according to the present invention can be used as a binder for an electrode (cathode or anode) or as a coating for a battery separator.

[0063] Said inventive copolymer according to the present invention or said inventive composition according to the present invention can be used as a binder for an electrode. Thus, according to another aspect, the present invention provides an electrode composition comprising said inventive copolymer according to the present invention or said inventive composition according to the present invention, an active material and optionally a conductive agent.

[0064] In a preferred embodiment, the electrode composition has the following mass composition: a. 50% to 99.95% active material, preferably 50% to 99% active material, b. 25% to 0% conductive agent, preferably 25% to 0.5%, c. 25% to 0.05% of the inventive polymer according to the present invention or said inventive composition according to the present invention, preferably 25% to 0.5%, d. 0% to 5% of at least one additive chosen from the group consisting of a plasticizer, an ionic liquid, a dispersing agent for a conductive additive, and an auxiliary flow agent; the sum of all percentages of components in the electrode composition being 100%.

[0065] The conductive agents in the electrode are composed of one or more materials that can improve conductivity. Some examples include carbon blacks such as acetylene black, Ketjen black; carbon fibers, such as a carbon nanotube, a carbon nanofiber, a carbon fiber by vapor phase growth; metal powders such as SUS powder, and aluminum powder.

[0066] The active materials in the electrode compositions are materials that are capable of storing and releasing lithium ions.

[0067] In a preferred embodiment, said electrode is a negative electrode. For a negative electrode, said active material is chosen from the group consisting of a lithium alloy, lithiummetal, a metal oxide, a carbon material such as graphite or hard carbon, silicon, an alloy of silicon and Li4Ti50i2. The form of the negative electrode active material is not particularly limited but is preferably particulate.

[0068] In another preferred embodiment, said electrode is a positive electrode (cathode). Preferably, for a positive electrode, said active material is chosen from the group consisting of LiCoCL, Li(Ni, Co, AI)O2, Li<i+X)NiaMnbCoc(x represents a real number of 0 or more, a = 0 .9, 0.8, 0.6, 0.5, or 1 / 3, b = 0.05, 0.1, 0.2, 0.3, or 1 / 3, c = 0.05, 0 ,1, 0.2, or 1 / 3), LiNiO2, LiMn2O4, LiCoMnO4, LisNiMmOi, Li3Fe2(PO4)3, Li3V2(PO4)3, a Li Mn spinel substituted with a different element having a composition represented by Lii+xMn -x.yMyO4, M representing at least one metal chosen from Al, Mg, Co, Fe, Ni, and Zn, x and y independently representing a real number between 0 and 2, lithium titanate LixTiOy- x and y independently representing a real number between 0 and 2, and a lithium metal phosphate having a composition represented by LiMPO4, M representing Fe, Mn, Co, or Ni. The shape of the positive electrode active material is not particularly limited but is preferably particulate. Additionally, the surface of each of the materials described above can be coated. The coating material is not particularly limited if it has lithium-ion conductivity and contains a material capable of being maintained as a coating layer on the surface of the active material. Examples of the coating material include LiNbCL, Li4Ti50i2, and LisPCL.

[0069] Said electrode composition can be deposited on at least one face of a current collector to form said electrode. This deposition can be carried out in the presence of an organic solvent, water, a mixture of the two or by a solvent-free process. Said organic solvent may be selected from the group consisting of n-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO), N,N- dimethylformamide (DMF), tri ethylphosphite (TEP), acetone, cyclopentanone, tetrahydrofuran, methyl ethylketone (MEK), methyl isobutyl ketone (MiBK), ethyl ester (EA), butyl ester (BA), ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), gamma-butyrolactone and N-butylpyrrolidone; and mixtures thereof.

[0070] According to another aspect of the present invention, a Li-ion battery is provided. Preferably, the Li-ion battery comprises a positive electrode, a negative electrode and a separator, at least one electrode being an electrode according to the present invention. Said battery preferably comprises an electrolyte salt selected from the group consisting of LiCFsSCL,LiPF6, LiC104, LiBF4, LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F3)2, LiN(SO2C2F5)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2C2F5), LiN(SO2CF3)(SO2C2F5),LiAsF6, LiBF2C2O4, LiNO3, LiPF3(CF2CF3)3, LiBETI (Lithium bis(pentafluoroethanesulfonyl)imide), LiTDI (Lithium 4,5-dicyano-2-trifluoromethylimidazole), or a mixture thereof.

[0071] According to another aspect of the present invention, said inventive copolymer according to the present invention or said inventive composition according to the present invention can be used as a coating in a separator placed between two electrodes. Said separator according to the present invention comprises a coating comprising, preferably consisting of, said inventive copolymer according to the present invention or said inventive composition according to the present invention, optionally placed on one or both faces of a porous support. In this case, the coating is used to coat the support of a separator, on at least one side, in the form of a single layer or multilayers. There is no limitation in the choice of the support, which is coated with the coating of the invention, if it is a porous substrate having pores. When it comprises several layers, the coating as described in the present invention is placed on the external face of the support, which is to say on the face which will first be in contact with the electrolytic composition used in the battery. Advantageously, the coating is applied to the support using an aqueous or solvent method. The porous substrate may take the form of a membrane or fibrous tissue. When the porous substrate is fibrous, it may be a non-woven web forming a porous web, such as a web obtained by direct spinning or melt-blowing (of the "spunbond" or "melt blown" type) or electrospinning. Examples of porous substrates useful in the invention as a support include, but are not limited to: polyolefins, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone , polyether sulfone, poly(phenylene oxide), poly(phenylene sulfide), polyethylene naphthalene or mixtures thereof. However, other heat-resistant engineering plastics may be used without limitation. Non-woven materials made from natural and synthetic materials can also be used as the separator substrate. The porous substrate generally has a thickness of 1 to 50 pm and are typically membranes obtained by extrusion and stretching (wet or dry process) or cast from nonwovens. The porous substrate preferably has a porosity of between 5% and 95%. The average pore size (diameter) is preferably between 0.001 and 50 pm, more preferably between 0.01 and 10 pm. The support can also be aluminum or aluminum coated with a polymer layer.

[0072] In addition to said composition, the separator coating may contain inorganic particles which serve to form micropores in the coating (the interstices between inorganic particles). The addition of inorganic particles can also contribute to heat resistance or improve wettability. According to one embodiment, said coating comprises from 50 to 99 weight percent of inorganic particles, relative to the weight of the coating. These inorganic particles must be electrochemically stable (not subject to oxidation and / or reduction in the range of voltages used). Furthermore, powdery inorganic materials preferably have high ionic conductivity. Low density materials are preferred over higher density materials because the weight of the battery produced can be reduced. The dielectric constant is preferably equal to or greater than 5. According to one embodiment, said inorganic particles are chosen from the group consisting of: BaTiCh, Pb(Zr,Ti)O3, Pbi-xLaxZryO3(0<x<l, 0<y<l), PbMgi / 3Nb2 / 3O3, PbTiO3, HfO, HfO2, SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, Y2O3, bohemite (y-AlO(OH)), A12O3, TiO2, SiC, ZrO2, borosilicate, BaSCh, nano-clays, or their mixtures. The separator coating may optionally comprise from 0 to 15% by weight based on the polymer, and preferably 0.1 to 10% by weight of additives, chosen from thickeners, pH adjusting agents, anti-sedimentation, surfactants, wetting agents, fillers, anti-foaming agents and fugitive or non-fugitive adhesion promoters. The fillers mentioned here in the additives are different from the inorganic particles mentioned above.

[0073] According to another aspect of the present invention, a Li-ion battery is provided. Preferably, the Li-ion battery comprises a positive electrode, a negative electrode and said separator according to the present invention. Said battery preferably comprises an electrolyte salt selected from the group consisting of LiCF3SO3, LiPFe, LiCICL, LiBF4, LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F3)2, LiN(SO2C2F5)2, LiN(SO2F)(SO2CF3), LiN(SO2F)(SO2C2F5), LiN(SO2CF3)(SO2C2F5),LiAsF6, LiBF2C2O4, LiNO3, LiPF3(CF2CF3)3, LiBETI (Lithium bis(pentafluoroethanesulfonyl)imide), LiTDI (Lithium 4,5-dicyano-2-trifluoromethylimidazole), or a mixture thereof.

[0074] According to another aspect of the present invention, said inventive copolymer according to the present invention or said inventive composition according to the present invention can be used in the preparation of a conductive polymer, a solid electrolyte for fuel cells, paints, cables, wires, anti-corrosion equipment for the chemical industry, coatings for construction or architecture. Said inventive copolymer according to the present invention or said inventive composition according to the present invention have applications in the field of batteries,semiconductors and electronics, oil and gas, automobiles, cables, architecture, and construction, aerospace, in the chemical industry where the inventive copolymer according to the present invention or said composition according to the present invention can be used in production processes, in storage or transport equipment, as an anti-corrosion agent.

[0075] The copolymers of the invention can be formulated as solvent dispersions, solvent solutions, aqueous dispersions, or as powder coatings, or in the form of powders, pellets, granules, sheets, films, extrudates, laminates or molded articles. The copolymers of the invention may be used as the sole polymeric component of such formulations, or they may be blended with other types of polymers. Such formulations may contain additives typical for use in a coating, including but not limited to, pH adjustment agents, cosolvents, coalescents, plasticizers, UV stabilizers, colorants, dyes, filler, water-soluble resins, rheology control additives and thickeners, and pigments and pigment extenders.

[0076] The copolymers of the invention may be useful as components of field-applied and factory applied coatings and paints, tank linings, anti-reflective coatings, caulks, sealants and adhesives, inks and varnishes, modifying resins for cements and mortars, consolidating agents, and stains; battery separators, binders for battery anodes or cathodes; medical devices or other products where biocompatibility may be advantageous; piezoelectric devices, The copolymers of the invention may be useful as components of energy surge devices, capacitive elements or insulating elements for batteries, supercapacitors, and other electrical energy storage devices; photovoltaic devices; insulating or barrier layers (e.g., oxygen barrier layers); dielectric layers; tie layers; adhesive layers; conductive layers; packaging fdms; and membranes and other filtration devices. Formulations containing the copolymers of the invention are particularly useful when there are requirements of weatherability, electrochemical stability, chemical resistance, stain / oil resistance, and / or hydrophobicity / water resistance.

[0077] Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.

[0078] Characterization methods

[0079] Latex solids content was determined using a Mettler-Toledo HR83 halogen moisture analyzer.

[0080] Latex particle size was determined using a Particle Sizing Systems, Inc. NICOMP analyzer.

[0081] Melt viscosity was determined using a Dynisco LCR7000 series capillary melt rheometer at 232C at 100 sec-1 per ASTM D3835-16.

[0082] Powder particle size was measured using a Microtrac Sync diffraction and dynamic image analysis analyzer.

[0083] 1H NMR spectrum of the product was recorded under the following conditions. a. Apparatus: AV III HD 500 Bruker Spectrometer. b. Frequency: 500 MHz c. Measurement solvent: 1% solution in DMSO-d6 d. Measurement temperature: 25°C

[0084] The1H NMR spectrum was analyzed to determine the contents of structural units derived from vinylidene fluoride and of structural units derived from vinyl hydrogen glutarate (VHG) in the polymer, based on the ratio of integral intensities of the signal from 5.1 to 5.7 ppm assigned to VHG and of the signals from 2.1 to 2.4 ppm and from 2.6 to 3.2 ppm assigned to vinylidene fluoride.

[0085] Rheological analysis of battery formulations

[0086] Formulations were analyzed at 25°C using a TA Instruments HR10 parallel plate rheometer with 40 mm diameter and gap of 500 pm. A shear rate sweep from 1 s'1to 100 s'1was performed. The 10 s1value was taken as representative and is used to compare the samples. Formulations were then rolled on a bottle roller at 33rpm at room temperature for 48 hours. The formulation viscosity measurement was then repeated to determine the stability of the viscosity over time.

[0087] Peel strength measurements

[0088] Peel strength of the electrodes was determined by cutting them into 20x80 mm specimens and subjected to a 180° peel test with an INSTRON 34SC-1 tensile tester at a head speed of 50 mm / min per ASTM D903.

[0089] Positive electrode (cathode) formulation and electrode preparation method with NMC active material a. Raw materials: NMC811 S85E from Ronbay, Carbon black C65 from Imeris, anhydrous N-methyl pyrrolidone 99.5% (<50ppm H2O)

[0090] 1.5 parts of binder was dissolved in 17.25 parts ofNMP for 48h on ajar roll mixer at room temperature at 33 rpm. 1.5 parts of carbon black was added to the produced binder solution and mixed (2000 rpm, 8 minutes) by using an ARE-250 Thinky mixer. 97 parts of NMC811 were then added and the mixture was mixed twice for three-minute periods at 2000rpm. It was then mixed twice for two-minute periods at 2000 rpm. In between each mixing step, approximately 5.0g of NMP was added. A total of 19.8 g of NMP was added during this procedure for a final solids content of 73%.

[0091] Coating of the positive electrode (NMC active material)

[0092] Each of the obtained positive electrode slurries were coated onto aluminum foil having a thickness of 20 pm using a roll-to-roll coating line with a speed of 0.2 m / min using a using knife coating method with a wet thickness of 180 pm. Dry electrodes with a loading of 22mg / cm2were obtained after evaporation of the solvent in a forced-air convection oven by passing through two Im long ovens with forced-air convection, respectively at 50°C and 90°C, respectively.

[0093] Positive electrode (cathode) formulation and electrode preparation method with LFP active material

[0094] All raw materials were purchased, stored in humidity-controlled laboratory and used as received. LFP active material YN-7 was from Hunan Yuneng New Energy Battery Material Ltd. Carbon black SuperP was from Imerys. N-Methylpyrrolidone (NMP) biotech grade was from Sigma-Aldrich.

[0095] All manipulations occurred within a humidity-controlled laboratory set at -40°C dew point. A binder solution in NMP was prepared by dissolving 3 parts binder into 47 parts NMP for 48h on a roll mixer at 50 °C at 10 RPM. Next, 2 parts carbon black was mixed with 33.3 parts of the binder solution through use of an ARE-250 Thinky mixer (6 min. @ 2000rpm). 96 parts of the LFP active material was then added along with NMP and then mixed again (2 min. @ 2000rpm). Finally, the slurry was diluted with additions of l-2g ofNMP stepwise over 5 steps, with additionalmixing (2 min. @ 2000rpm) between each step until a total of 9.4g of NMP was added. The resulting cathode slurry had homogeneous appearance and had solids content of 59.6% by mass.

[0096] The cathode slurry was immediately coated onto a current collector, aluminum foil of thickness 20 microns with a doctor blade (350mm gap) on a drawdown table. The NMP solvent was evaporated from the coating via convection oven drying (120 °C, 15 min.), yielding an electrode of 126 pm thickness with mass loading 24.0 mg / cm2. Dried electrode was then densified via calendaring press (0.25MPa) prior to testing.

[0097] Electrode peel force was evaluated by 180° peel adhesion test according to ASTM D903 at peel rate 50mm / min.

[0098] VHG Monomer Synthesis

[0099] Transvinylation catalyst and VHG syntheses were adapted from US5214172B2 and Barbara, I., et.al, ARKIVOC 2016 (iii) 23-35, respectively.

[0100] Catalyst dipyridine palladium diacetate [Pyr]zPd(OAc)2 was synthesized by reaction of palladium (II) acetate (1 eq) with pyridine (2eq.) in a mixture of diethyl ether and toluene (1 :3 w / w), (total molar concentration 0.4 mol / L). The mixture was stirred for 4h at room temperature. Product was vacuum filtered, washed with pentane and dried in a vacuum desiccator overnight, (yield: 99% of light-brown powder).

[0101] Example M-In a 2 -liter, 2 neck round bottom flask, 100.0g of glutaric acid, 325.8g of vinyl acetate and 14.4g of p-toluene sulfonic acid were dissolved in 450g of dimethylformamide. 3.6 g of [Pyr]2?d(OAc)2 was added, and the mixture was heated at 60°C for 110 minutes. The mixture was cooled to room temperature, and an aqueous solution of potassium acetate (7.4 g, 0.1 eq, solubilized in 450 m of deionized water) was added. The mixture was transferred to a separatory funnel and extracted twice with 1200 m of diethyl ether. The organic phases were combined and washed four times with 600 mb each of deionized water. The organic phase was vacuum filtered through a pad of Celite which was previously wetted with diethyl ether. The collected ether solution was then dried by addition of 10g of anhydrous sodium sulfate. The ether solution / sodium sulfate mixture was gently swirled for 5 minutes. Sodium sulfate was removed by vacuum filtration and the diethyl ether was removed from the solution vacuum evaporation (60°C, 20 mbar). The raw product containing both VHG and divinyl glutarate by-product was then purified by vacuum distillation (90 to 115°C, 0.1 mbar). Vinyl hydrogen glutarate (VHG) was recovered as a clear oilfraction distilling at 1 10-115 °C (38.0 g, yield=31 .7%). NMR was used to determine the synthesized structure.1H NMR (400 MHz, acetone-de) 8 10.61 (s, 1H), 7.29 (dd, J = 14.0, 6.3 Hz, 1H), 4.87 (dd, J = 14.0, 1.5 Hz, 1H), 4.60 (dd, J = 6.3, 1.5 Hz, 1H), 2.54 (t, J = 7.4 Hz, 2H), 2.42 (t, J = 7.3 Hz, 2H), 1.93 (p, J = 7.4 Hz, 2H). The monomer molecular weight was 158 Daltons.

[0102] Copolymerization Examples

[0103] Example 1 : P(VDF-co-VHG) copolymer (Polymer A) Copolymerization was carried out in a 3L vertical reactor equipped with pitched blade agitator. The reactor was charged with 2295 g of water, 23.5 g of a solution containing 21.7 g / L of Methocel F50 PVC, and 2.6 g of ethyl acetate. Subsequently, 19 g of a solution containing lOg / L of vinyl hydrogen glutarate (VHG) (from Example M above) was introduced into the reactor. Vacuum was applied to the reactor for removal of oxygen, prior to the introduction of 510 g of vinylidene fluoride. Agitation of reactor contents was started at a rate of 750 rpm, and 1 g of n- propyl peroxydicarbonate was added. The temperature was then raised to 44°C, and the pressure increased to 90 bar. To maintain the pressure at 90 bar throughout the polymerization, a 10 g / L aqueous solution of VHG was continuously introduced into the reactor. The polymerization reaction was conducted for 150 minutes, during which a total of 264 g of VHG solution was injected. At that point, the reactor was vented of residual VDF gas, cooled to room temperature and the aqueous slurry product was discharged. The solid polymer was filtered, rinsed with deionized water and dried in a forced-air oven at 60C for 24 hours, yielding 290 g of Polymer A as a powder with average particle diameter of greater than 50 pm.

[0104] Example 2: P(VDF-co-acrylic acid) copolymer (Comparative Example, Polymer B)

[0105] Copolymerization was conducted in a 3L vertical reactor. The reactor was charged with 1380 g of water, 30.2 g of a solution containing 23.0 g / L of Methocel F50 PVC, and 6.4 g of ethyl acetate. A vacuum was applied to the reactor prior to the introduction of 1156 g of vinylidene fluoride. The reactor was stirred at 750 rpm, and 1.73 g of n-propyl peroxydicarbonate was added as an initiator. The temperature of the reactor was raised to 44°C, and the internal pressure increased to 90 bar. To maintain the pressure at 90 bar throughout the polymerization, a 4.6 g / L aqueous solution of acrylic acid was continuously introduced into the reactor. The polymerization reaction was carried out for 330 minutes, during which a total of 837 g of acrylic acid solution wasinjected. Upon completion, the polymer was washed and dried, yielding 858 g of polymer B with average particle diameter of greater than 50 pm.

[0106] Example 3 P(VDF-co-VHG) copolymer (Polymer C)

[0107] To a 2-liter horizontal, agitated autoclave were added 600g of deionized water. A 2.0 wt.% solution of VHG comonomer in deionized water was produced by adding 10.0g of VHG to 490.0g of deionized water with vigorous stirring. A solution of potassium persulfate (KPS) (3.0wt%) in deionized water was produced by adding 15.0g of KPS to 485.0g of deionized water with vigorous stirring for 1 hr. The autoclave agitation was started at 72rpm, heated to 83C pressurized to 60psi (414kPa) with nitrogen and vented to atmospheric pressure. This process was repeated two more times to deoxygenate the reactor contents. The reactor was then pressurized to 650psi (4482 KPa) with vinylidene fluoride. KPS solution was introduced to the reactor at a rate of 3.0 mL / min until a pressure decrease of 1.0 psi (6.9kPa) to 649psi (4482 kPa) was noted. At that point, KPS solution feed rate was decreased to 2.0 mL / min. VHG solution was then fed at an average rate of 3.3mL / min along with VDF to maintain reactor pressure at 650psi (4482 KPa). The reaction was continued for 90 minutes at these conditions whereby a total of 297.8mL of VHG solution and 279g of VDF had been added. At that point, VHG solution and VDF feeds were stopped, and KPS solution feed rate was decreased to 0.5mL / min. Reactor pressure was allowed to drop autogenously to 130psi (896 kPa), and cooled to 33C at which point reactor pressure was 99psi (683 kPa). Residual VDF gas was then vented, bringing reactor pressure to equal to atmospheric pressure. Agitation was stopped and reactor contents drained, yielding 1433.4g of latex with solids of 30.2%. 415g of a coarse powder was obtained by drying the latex in a forced-air convection oven at 60 °C overnight (Polymer C). Melt viscosity was 37.7kPoise at 100 sec-1.

[0108] Polymer D is PVDF made according to US 11,643,484 B2.

[0109] Table 1: Characterization data for the experimental polymers

[0110] Use of VHG monomer in the vinylidene fluoride copolymerization results in a significant reduction of polymerization time required for equivalent or greater comonomer incorporation into the product. This is an advantage as lower polymerization times lead to higher productivity and lower cost for commercial production.

[0111] Table 2 : Formulation test data for NMC active material

[0112] Inventive NMC Formulation Example 1 shows very little increase of slurry viscosity after 48 hours, similar-to, or better-than comparative NMC Formulation Example 2 and NMC Formulation Example 3. Temporal stability of slurry viscosity is an important parameter for consistent commercial production of battery electrodes.

[0113] Table 3: Electrode test data for NMC active material

[0114] Cathode made with NMC formulation, NMC Electrode Example 1 , exhibits an outstanding peel strength as compared to electrodes made with comparative NMC Electrode Example 2 and NMC Electrode Example 3. High peel strength is an indication that the electrode will have robust performance during electrode handling and during use in a battery.

[0115] Volume resistivity of the NMC Electrode Example 1 is similar-to or lower-than those produced in comparative NMC Electrode Example 2 and NMC Electrode Example 3 where low resistivity is preferred for improved cathode performance in a battery.

[0116] Table 4: Electrode peel test data for LFP active material

[0117] Polymer E is a PVDF homopolymer made by emulsion polymerization.

[0118] Peel strength of LFP Electrode Example 1 shows higher peel strength as compared to comparative LFP Electrode Example 2. High peel strength is an indication that the electrode will have robust performance during electrode handling and during use in a battery.

Claims

What is claimed is:

1. A fluorinated copolymer comprising, in polymerized form, a) at least one fluorinated olefin monomer unit and b) at least one functional vinyl ester monomer unit.

2. The fluorinated copolymer of claim 1, wherein the at least one fluorinated olefin comprises a fluorinated olefin represented by formula (1):CX1X2=CX3X4(1) wherein the fluorinated olefin comprises at least one halogen atom and X1, X2, and X3are independently selected from the group consisting of a hydrogen atom, a chlorine atom, a fluorine atom, and a fluorinated or non-fluorinated alkyl group having 1 to 16 carbon atoms, preferably 1 to 8 carbon atoms; X4is selected from the group consisting of a hydrogen atom, a chlorine atom, a fluorine atom, a fluorinated or non-fluorinated alkyl group having 1 to 16 carbon atoms, preferably 1 to 8 carbon atoms; and fluorinated or non-fluorinated Cl -Cl 6 alkyl ether groups, preferably 1 to 8 carbon atoms, subject to the proviso that the fluorinated olefin comprises at least one fluorine atom.

3. The fluorinated copolymer of claim 1, wherein said fluorinated olefin comprises vinylidene fluoride.

4. The fluorinated copolymer of claim 1, wherein said fluorinated olefin comprises vinylidene fluoride and hexafluoropropylene.

5. The fluorinated copolymer of any one or more of claims 1 to 4, wherein the one functional vinyl ester monomer unit comprises an acid group or salt thereof.

6. The fluorinated copolymer of any one or more of claims 1 to 4, wherein said at least one functional vinyl ester, has the formula, Formula (2):Wherein Ri, R2 and R3 are independently selected from a hydrogen atom, a chlorine atom, or nonfluorinated alkyl group, andR4 is selected from a bond, a heteroatom, an organic group with a molecular weight of not more than 500 Daltons containing carbon, hydrogen and optionally at least one heteroatom selected from oxygen atom, nitrogen atom, and having a main chain comprising from 1 to 16 carbon atoms, preferably R4 is a Cl -Cl 6 hydrocarbon group, optionally containing non-carbon-carbon-bond linkages selected from ether, ester, amide, amine, urethane, urea, imine, imide, and may optionallycontain one or more pendent heteroatom-containing groups selected from a ketone, epoxide, alcohol, and amine group, and Ai is an acid, acid salt or alkyl ester group.

7. The fluorinated copolymer of any one or more of claims 1 to 4, wherein said at least one functional vinyl ester, has the formulaFormula (Wherein Ri, R2 and R3 are independently selected from H, a Cl, C2, C3, C4, C5, C6, C7, or C8 alkyl group; a C3, C4, C5, C6, C7, or C8 branched alkyl group, and R4 is a bond, a Cl, C2, C3, C4, C5, C6, C7, C8, C9, CIO, Cl 1, C12, C13, C14, C15 or C16 alkyl group; C3, C4, C5, C6, C7, C8, C9, CIO, Cl 1, C12, C13, C14, C15 or C16 branched alkyl group; a C3, C4, C5, C6, C7, C8, C9, CIO, C11, C12, C13, C14, C15 or C16 cycloalkyl group ,and may optionally contain additional non-carbon-carbon-bond linkages between carbon atoms of the C2 to C16 groups selected from ether, ester, amine, or amide; and may optionally contain one or more pendent heteroatom-containing groups selected from ketone, epoxide, alcohol, amine; and Ai is carboxylic acid, phosphonic acid, sulfonic acid, or a salt or ester of any of the acids.

8. The fluorinated copolymer of claim 7, wherein, the functional vinyl ester co monomer comprises, or consists of: Formula 2, wherein Ri, R2 and R3 are hydrogen, R4 is a C2, C3, C4, C5, or C6 alkyl group and Ai is a carboxylic acid or salt or alkyl ester group thereof.

9. The fluorinated copolymer of claim 7, wherein the functional vinyl ester co monomer comprises, or consists of: Formula 2, wherein Ri, R2 and R3 are H, R4 is a Cl alkyl group or a bond and Ai is a carboxylic acid or salt or alkyl ester group thereof.

10. The fluorinated copolymer of claim 7 wherein, the functional vinyl ester co monomer comprises, or consists of: Formula 2, wherein Ri, R2 and R3 are H, R4 is a C2, C3, C4, C5, or C6 alkyl group and Ai is a phosphonic acid or salt or alkyl ester group thereof.

11. The fluorinated copolymer of claim 7 wherein, the functional vinyl ester co monomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 is comprises a C3, alkyl group and Ai is a carboxylic acid or salt or alkyl ester group form.

12. The fluorinated copolymer of claim 7 wherein, the functional vinyl ester co monomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 comprises a C4 alkyl group and Ai is a carboxylic acid or salt form or alkyl ester group.

13. The fluorinated copolymer of claim 7 wherein, the functional vinyl ester co monomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 comprises a C5 alkyl group and Ai is a carboxylic acid or salt form or alkyl ester group.

14. The fluorinated copolymer of claim 7 wherein, the functional vinyl ester co monomer comprises, or consists of: Formula 2, where Ri, R2 and R3 are H, R4 comprises a C6 alkyl group and Ai is a carboxylic acid or salt form or alkyl ester group.

15. The fluorinated copolymer of any one or more of claims 1 to 14 comprising from 0.01 up to 50.0 wt% of said at least one functional vinyl ester monomer units.

16. The fluorinated copolymer of any one or more of claims 1 to 14, wherein the copolymer is comprised of from 50 to 99.99 % by weight fluorinated olefin and from 50 to 0.01% by weight functional vinyl ester in polymerized form.

17. A method of making a copolymer in accordance any one or more of claims 1-16, comprising copolymerizing a monomer mixture comprised of a) at least one fluorinated olefin and b) at least one functional vinyl ester.

18. A process for preparing the fluorinated copolymer of any one or more of claims 1-16 in an aqueous reaction medium, comprising: a) forming an aqueous dispersion comprising at least one fluorinated olefin, and at least one functional vinyl ester and optionally a surfactant, b) adding at least one initiator to the aqueous reaction medium, c) initiating copolymerization of said at least one fluorinated vinylic monomer with said one functional vinyl ester with stirring, wherein polymerization is carried out at a polymerization pressure of from about 2750 kPa to about 14000 kPa.

19. The process of claim 18, wherein polymerization is carried out at a temperature of from about 70 to about 125 degrees Celsius.

20. The process of any one of claims 18 to 19, wherein the initiator is a persulfate or an organic peroxide.

21. A process for preparing the fluorinated copolymer of any one or more of claims 1-16 by suspension polymerization in an aqueous reaction medium, comprising: c) forming an aqueous dispersion comprising a suspending agent, at least one fluorinated olefin, and at least one functional vinyl ester, d) adding at least one initiator to the aqueous reaction medium, c) initiating copolymerization of said at least one fluorinated vinylic monomer with said one functional vinyl ester with stirring, wherein polymerization is carried out at a polymerization pressure of from about 2000 and 20,000 kPa.

22. The process of any one of claim 21, wherein polymerization is carried out at a temperature of from about 20 to about 120 degrees Celsius.

23. The process of any one of claims 21 to 22, wherein the initiator is an organic peroxide.

24. A formulation comprising the fluorinated copolymer of any one or more of claims 1 to 16, in a solvent, wherein said solvent is selected from the group consisting of n-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), triethylphosphite (TEP), acetone, tetrahydrofuran, methyl ethylketone (MEK), methyl isobutyl ketone (MiBK), ethyl ester (EA), butyl ester (BA), dimethyl carbonate (DMC), diethyl carbonate (DEC) and methyl ethyl carbonate (MEC) and further comprising activated carbon and metal particles in said solvent, said metal particles being selected from the group consisting of lithium iron phosphate (LFP), lithium nickel manganese cobalt oxide (NMC), lithium-manganese-cobalt-oxide, lithium-nickel-cobalt- aluminum oxide, lithium-manganese oxide, and lithium-nickel-manganese (LMNO).

25. An article, comprising a substrate having a surface and a coating comprised of a fluorinated copolymer in accordance with any one or more of claims 1 to 16 on at least a portion of the surface of the substrate.

26. A positive electrode mixture for nonaqueous electrolyte secondary batteries comprising the fluorinated copolymer of any one or more of claims 1 to 16, a lithium-based positive electrode active material and a nonaqueous solvent, preferably the fluorinated copolymer comprises a vinylidene fluoride copolymer.

27. A positive electrode for nonaqueous electrolyte secondary batteries obtained by applying the positive electrode mixture for nonaqueous electrolyte secondary batteries of claim 26 to a collector and drying the coating.

28. A battery electrode binder, comprising the fluorinated copolymer in accordance with any one or more of claims 1 to 16.

29. A battery, comprising at least one electrode comprising an electrode active material and a fluorinated copolymer in accordance with any one or more of claims 1 to 16.

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