Process of producing fluoropolymers using alkylsulfosuccinate

Abstract

The invention relates to a method of polymerizing fluoromonomers using non-fluorinated surfactants, in particular to an emulsion polymerization method using one or more alkylsulfosuccinates (used as the surfactant).

Description

PROCESS OF PRODUCING FLUOROPOLYMERS USING ALKYLSULFOSUCCINATE FIELD OF THE INVENTION

[0001] The invention relates to processes of polymerizing fluoromonomers using alkylsulfosuccinate, in particular to emulsion polymerization process for producing fluoropolymer latex and the products produced therefrom. BACKGROUND OF THE RELATED ART

[0002] Known processes for making fluoropolymers by an emulsion process commonly use perfluorinated or highly fluorinated surfactants to stabilize the emulsion during the reaction. For example, perfluorocarboxylate salts are used to stabilize fluoropolymer emulsion polymerizations, with the most common example being ammonium perfluorooctanoate. Fluorosurfactants are expensive, specialized materials, however, and because of their high stability, they tend to persist in the environment and now are under scrutiny of regulatory agencies. A process which uses a non- fluorinated surfactant to make fluoropolymers could solve these problems. In general, non- fluorinated surfactants have been used in emulsion polymerization of non-fluorinated monomers, while they had very limited success in conjunction with fluorinated monomers because they induce long inhibition time, low yield, and low molecular weight.

[0003] Historically, fluoropolymer latexes have been produced containing fluorinated surfactants. While latexes containing non-fluorinated surfactants have been invented, these inventions generally offer limited productivity related to total solids content.

[0004] It is known that this class of surfactants has a higher degree of biodegradability than many others, reducing the environmental impact of products using them.

[0005] US10105820B2 Daikin teaches that high temperatures with initiator other than organic peroxide leads to gelation.

[0006] US6806333B2 AGC Inc teaches the addition of dioctyl alkylsulfosuccinate to a fluororesin aqueous emulsion after the polymerization.

[0007] US9371405 Chemours and US8563670 DuPont Claim a siloxane polymer-functionalized alkylsulfosuccinate but mentions others. These teach a two-step addition where surfactant and initiator are added in equal amounts, surfactant is degraded and then VDF is charged to the reactor.

[0008] US9567413B2 Daikin discloses a copolymer with non-fluorinated vinyl monomer and non- fluorinated monomer with a cross-linkable group. All the examples used tetrafluoroethylene as the majority amount of fluoromonomer.

[0009] US9786917 Asahai teaches 0.1 to 5 wt% surfactant. Asahai ‘917 also teach adding a second phenyl-containing surfactant after the polymerization to stabilize the latex. Asahai ‘917 teaches the following a dialkyl sulfosuccinate such as sodium dioctyl sulfosuccinate, sodium didecyl sulfosuccinate, sodium dihexyl sulfosuccinate, sodium diisobutyl sulfosuccinate, sodium diamyl sulfosuccinate or ammonium dioctyl sulfosuccinate.

[0010] US20160108225 A1 Asahai teaches to obtain a fluorinated polymer having a high molecular weight using a surfactant having a critical micelle concentration (CMC) below 0.09 mass % in aqueous media is used. The examples are all fluorinated elastomer examples.

[0011] The present invention discloses the use of certain alkylsulfosuccinate in polymerization of fluroromonomer to produce fluoropolymer latex and the composition of said fluoropolymer latex. SUMMARY OF THE INVENTION

[0012] The present invention provides a process for preparing a fluoropolymer in an aqueous emulsion reaction medium, comprising an alkylsulfosuccinate. A radical initiator is added to initiate the polymerization reaction. Preferably, the alkylsulfosuccinate has a CMC above 0.1 mass% and less than 10 wt%.

[0013] A polymerization reaction in accordance with this invention may be carried out by charging a reactor with water (preferably deionized water), at least one alkylsulfosuccinate (as the surfactant), and at least one fluoromonomer. The process may optionally include at least one chain-transfer agent, and at least one antifoulant. A radical initiator is added to the reactor to initiate the polymerization reaction.

[0014] It has unexpectedly been discovered that the presence of an alkylsulfosuccinate during emulsion polymerization of a fluoromonomer permits the production of a fluoropolymer latex.

[0015] The invention provides a process for producing a polyvinylidene fluoride latex by emulsion polymerization of vinylidene fluoride in the absence of a fluorinated surfactant, said process comprising the steps of: i. charging a polymerization reactor with deionized water and an alkylsulfosuccinate, ii. optionally adding a chain transfer agent, iii. optionally adding a buffer, iv. optionally adding a paraffin antifoulant, v. raising the temperature to a suitable temperature (suitable temperatures as described herein), vi. feeding vinylidene fluoride to the reactor until the pressure reaches a suitable pressure (suitable pressures as described herein), vii. adding an initiator to start the polymerization, viii. continuously feeding vinylidene fluoride to maintain said pressure and optionally adding additional initiator, ix. stopping the vinylidene fluoride feed when the desired amount of polymer conversion has been reached, x. optionally continuing the initiator feed to consume the residual vinylidene fluoride,

[0016] The invention provides for a polyvinylidene fluoride latex comprising a polyvinylidene fluoride polymer and alkylsulfosuccinates wherein polyvinylidene fluoride polymer comprises greater than 75 wt% VDF monomer units and the weight average particle size of said polyvinylidene fluoridepolymer is between 10 and 350 nm. The alkylsulfosuccinates are described herein. The amount of alkylsulfosuccinate in the latex may be from 10 to 1000ppm, or 50 to 750 ppm of one or more based on total latex weight.

[0017] In some embodiments the polyvinylidene fluoride latex may be dried. The invention provides for a polyvinylidene fluoride polymer composition comprising a polyvinylidene fluoride polymer and alkylsulfosuccinate wherein polyvinylidene fluoride polymer comprises greater than 75 wt% VDF monomer units and the weight average particle size of said polyvinylidene fluoride polymer is between 10 and 350 nm. The alkylsulfosuccinates are described herein. The amount of alkylsulfosuccinate present in the composition may be from 50 ppm to 2500, more preferably between 50 ppm and 2000 ppm, 300 ppm to 1500 ppm based on polyvinylidene fluoride polymer weight.

[0018] Advantageously, the preparation of high solid content PVDF latex uses alkylsulfosuccinate as a biodegradable non-fluorinated surfactant. By high solid content we mean a solid content greater than 28% solids.

[0019] Embodiments of the Invention include:

[0020] Embodiment 1 provides a process of producing an aqueous latex of polyvinylidene fluoride by emulsion polymerization in the absence of a fluorinated surfactant comprising: a. charging a polymerization reactor with deionized water and one or more alkylsulfosuccinates, b. optionally adding one or more of chain transfer agent, buffer, paraffin antifoulant, c. feeding monomer comprising VDF to the reactor until the pressure reaches at least 280 kPa thereby forming an reaction mixture, d. feeding an initiator to the reaction mixture, e. polymerizing said fluoromonomer to produce an aqueous fluoropolymer latex wherein the one or more alkylsulfosuccinate has the formulawhere X = SO3M or H, Y = SO3M or H, wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium or alkaline earth metal ion, with the proviso that X and Y cannot simultaneously be H, where R1 and R2 are, independently H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising 1 to 12 carbon units, preferably 3 to 10 carbon units, with the proviso that at least one of R1 and R2 is an alkyl moiety, wherein the one or more alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass% and wherein the one or more alkylsulfosuccinate is added in an amount of from 50 ppm to 2500 ppm, based on weight of fluoromonomer in the process, andwherein the amount of vinylidene fluoride monomer based on total fluorinated monomer used in the process comprises at least 75wt%.

[0021] Embodiment 2 provides the process of embodiment 1, wherein the one or more alkylsulfosuccinate has a critical micelle concentration in water of at least 0.50 mass percent, or at least 1.0 mass percent, or at least 1.2 mass %.

[0022] Embodiment 3 provides the process of any one or more of embodiments 1 to 2, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least one branch.

[0023] Embodiment 4 provides the process of any one or more of embodiments 1 to 2, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least two branches.

[0024] Embodiment 5 provides the process of any one or more of embodiments 1 to 4, wherein R1 and R2 are the same.

[0025] Embodiment 6 provides the process of any one or more of embodiments 1 to 2, wherein the alkylsulfosuccinate comprises at least one of dipropyl sulfosuccinate, di-isopropyl sulfosuccinate, dibutyl sulfosuccinate, di-isobutyl sulfosuccinate, di-secbutyl sulfosuccinate, diamyl sulfosuccinate, bis(1-methyl butyl) sulfosuccinate, bis (2-methyl butyl) sulfosuccinate, bis(3-methyl butyl) sulfosuccinate, bis(1,3-dimethyl butyl) sulfosuccinate, bis (2,3-dimethyl butyl) sulfosuccinate, bis(1,2,2-trimethyl propyl) sulfosuccinate, bis (1,1,2-trimethyl propyl) sulfosuccinate, bis(ethyl hexyl) sulfosuccinate or a salt thereof.

[0026] Embodiment 7 provides the process of any one or more of embodiments 1 to 2, wherein the alkylsulfosuccinate comprises an salt of bis(1,3-dimethyl butyl) sulfosuccinate.

[0027] Embodiment 8 provides the process of any one or more of embodiments 1 to 7, wherein the alkylsulfosuccinate is added to the aqueous reaction medium both before addition of initiator.

[0028] Embodiment 9 provides the process of any one or more of embodiments 1 to 8, wherein the one or more alkylsulfosuccinate is added to the reaction mixture in an amount of between 50 ppm and 2000 ppm, or 300 ppm to 1500 ppm, based on weight of vinylidene fluoride monomer used in the process.

[0029] Embodiment 10 provides the process of any one or more of embodiments 1 to 9, wherein chain transfer agent is added to the polymerization reaction.

[0030] Embodiment 11 provides the process of embodiment 10, wherein chain transfer agent comprises ethyl acetate.

[0031] Embodiment 12 provides the process of any one or more of embodiments 1 to 11, wherein the monomer does not comprise a crosslinkable group.

[0032] Embodiment 13 provides the process of any one or more of embodiments 1 to 12, wherein the monomer comprises at least one fluorinated monomer, in addition to the vinylidene fluoride monomer, selected from the group consisting of tetrafluoroethylene (TFE), trifluoroethylene,chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), vinyl fluoride, hexafluoroisobutylene, perfluorobutylethylene (PFBE), pentafluoropropene, 3,3,3-trifluoro-1- propene, 2-trifluoromethyl- 3,3,3-trifluoropropene, fluorinated vinyl ethers, fluorinated allyl ethers, non-fluorinated allyl ethers, fluorinated dioxoles, and the combinations.

[0033] Embodiment 14 provides the process of any one or more of embodiments 1 to 12, wherein the monomer comprises hexafluoropropene.

[0034] Embodiment 15 provides the process of any one or more of embodiments 1 to 14, wherein said initiator is a persulfate salt, selected from the group consisting of sodium persulfate, potassium persulfate, or ammonium persulfate, the amount of persulfate salt added to the reaction mixture, based upon the total weight of monomer added to the process, being from 0.005 to 1.0 weight percent.

[0035] Embodiment 16 provides the process of any one or more of embodiments 1 to 15, wherein the fluoropolymer is a copolymer of vinylidene fluoride and a second monomer, wherein the copolymer is from about 75 to about 99 weight percent vinylidene fluoride and from about 1 to about 25 weight percent the second monomer based on total fluoromonomer in the polymer.

[0036] Embodiment 17 provides the process of any one or more of embodiments 1 to 16, wherein said latex has a solid content of from 10 to 60 weight percent, preferably of 15 to 45 weight percent.

[0037] Embodiment 18 provides the process of any one or more of embodiments 1 to 17, wherein the process comprises adding at least one component selected from the group consisting of chain- transfer agents, buffering agents, antifoulants, and mixtures thereof.

[0038] Embodiment 19 provides a polyvinylidene fluoride latex comprising a polyvinylidene fluoride polymer and from 50 ppm to 2500 ppm of one or more alkylsulfosuccinates based on total polyvinylidene fluoride polymer weight, wherein polyvinylidene fluoride polymer comprises greater than 75 wt% VDF monomer units and the weight average particle size of said polyvinylidene fluoride polymer is between 10 and 350 nm, wherein the one or more alkylsulfosuccinate has the formulawhere X = SO3M or H, Y = SO3M or H, wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium or alkaline earth metal ion, with the proviso that X and Y cannot simultaneously be H, where R1 and R2 are, independently H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising 1 to 12 carbon units, preferably 3 to 10 carbon units, with the proviso that at least one of R1 and R2 is an alkyl moiety, and wherein the one or more alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass%.

[0039] Embodiment 20 provides the polyvinylidene fluoride latex of embodiment 19, wherein the one or more alkylsulfosuccinate has a critical micelle concentration in water of at least 0.50, or at least 1.0, or at least 1.2 wt %.

[0040] Embodiment 21 provides the polyvinylidene fluoride latex of embodiment 19 or 20, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least one branch.

[0041] Embodiment 22 provides the polyvinylidene fluoride latex of embodiment 19 or 20, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least two branches.

[0042] Embodiment 23 provides the polyvinylidene fluoride latex of embodiment 19, wherein the alkylsulfosuccinate comprises at least one of dipropyl sulfosuccinate, di-isopropyl sulfosuccinate, dibutyl sulfosuccinate, di-isobutyl sulfosuccinate, di-secbutyl sulfosuccinate, diamyl sulfosuccinate, bis(1-methyl butyl) sulfosuccinate, bis (2-methyl butyl) sulfosuccinate, bis(3-methyl butyl) sulfosuccinate, bis(1,3-dimethyl butyl) sulfosuccinate, bis (2,3-dimethyl butyl) sulfosuccinate, bis(1,2,2-trimethyl propyl) sulfosuccinate, bis (1,1,2-trimethyl propyl) sulfosuccinate, bis(ethyl hexyl) sulfosuccinate or a salt thereof.

[0043] Embodiment 24 provides the polyvinylidene fluoride latex of embodiment 19, wherein the alkylsulfosuccinate comprises a salt of bis(1,3-dimethyl butyl) sulfosuccinate.

[0044] Embodiment 25 provides the polyvinylidene fluoride latex of any one or more of embodiments 19 to 24, wherein the polymer comprises hexafluoropropene monomer units.

[0045] Embodiment 26 provides a polyvinylidene fluoride composition comprising a polyvinylidene fluoride polymer and from 50 ppm to 2500, or between 50 ppm and 2000 ppm, or 300 ppm to 1500 ppm of one or more alkylsulfosuccinates based on polyvinylidene fluoride weight, wherein the polyvinylidene fluoride polymer comprises greater than 75 wt% VDF monomer units and the weight average particle size of said polyvinylidene fluoride polymer is between 10 and 350 nm, wherein the one or more has the formulawhere X = SO3M or H, Y = SO3M or H, wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium or alkaline earth metal ion, with the proviso that X and Y cannot simultaneously be H, where R1 and R2 are, independently H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising 1 to 12 carbon units, preferably 3 to 10 carbon units, with the proviso that at least one of R1 and R2 is an alkyl moiety, and wherein the one or more alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass%.

[0046] Embodiment 27 provides the polyvinylidene fluoride composition of embodiment 26, wherein the one or more alkylsulfosuccinate has a critical micelle concentration in water of at least 0.50, at least 1.0, at least 1.2 wt %.

[0047] Embodiment 28 provides the polyvinylidene fluoride composition of embodiment 26 or 27 wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least one branch.

[0048] Embodiment 29 provides the polyvinylidene fluoride composition of embodiment 26 or 27, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least two branches.

[0049] Embodiment 30 provides the polyvinylidene fluoride composition of embodiment 26 or 27, wherein the alkylsulfosuccinate comprises at least one of dipropyl sulfosuccinate, di-isopropyl sulfosuccinate, dibutyl sulfosuccinate, di-isobutyl sulfosuccinate, di-secbutyl sulfosuccinate, diamyl sulfosuccinate, bis(1-methyl butyl) sulfosuccinate, bis (2-methyl butyl) sulfosuccinate, bis(3- methyl butyl) sulfosuccinate, bis(1,3-dimethyl butyl) sulfosuccinate, bis (2,3-dimethyl butyl) sulfosuccinate, bis(1,2,2-trimethyl propyl) sulfosuccinate, bis (1,1,2-trimethyl propyl) sulfosuccinate, bis(ethyl hexyl) sulfosuccinate or a salt thereof.

[0050] Embodiment 31 provides the polyvinylidene fluoride composition of embodiment 26 or 27, wherein the alkylsulfosuccinate comprises a salt of bis(1,3-dimethyl butyl) sulfosuccinate.

[0051] Embodiment 32 provides the polyvinylidene fluoride composition of anyone of more of embodiments 26 to 31 containing alkylsulfosuccinate comprising from between 50 ppm and 2500 ppm, or from 50 ppm and 2000 ppm, or from between 300 ppm to 1500 ppm of one or more alkylsulfosuccinates based on total polyvinylidene fluoride polymer weight.

[0052] Embodiment 33 provides the polyvinylidene fluoride composition of any one or more of embodiments 26 to 32, wherein the polyvinylidene fluoride polymer comprises hexafluoropropene monomer units. DETAILED DESCRIPTION OF THE INVENTION

[0053] As used herein, the term “about” means ±10% of the noted value. By way of example only, a composition comprising “about 30 wt. %” of a component could include from 27 wt. % of the component up to and including 33 wt. % of the component. The units of ppm is weight by weight unless other wise noted.

[0054] Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0055] The word "comprising" is used in a manner consistent with its open-ended meaning, that is, to mean that a given product or process can optionally also have additional features or elements beyond those expressly described. It is understood that wherever embodiments are described hereinwith open-ended meaning, otherwise analogous embodiments described in terms of “consisting of” and / or “consisting essentially of” are also contemplated and within the scope of this disclosure.

[0056] For the purposes of defining the present technology, the transitional phrase “consisting of” may be introduced in the claims as a closed preamble term limiting the scope of the claims to the recited components or steps and any naturally occurring impurities. For the purposes of defining the present technology, the transitional phrase “consisting essentially of” may be introduced in the claims to limit the scope of one or more claims to the recited elements, components, materials, or method steps as well as any non-recited elements, components, materials, or method steps that do not materially affect the novel characteristics of the claimed subject matter.

[0057] The different aspects, alternatives and embodiments of the invention disclosed herein can be combined with one or more of the other aspects, alternatives and embodiments described herein. Two or more aspects can be combined.

[0058] Various examples and embodiments of the inventive subject matter disclosed here are possible and will be apparent to a person of ordinary skill in the art, given the benefit of this disclosure. In this disclosure reference to “embodiments” means that those embodiments are non- limiting examples of the inventive subject matter, and there may be alternative embodiments which are not excluded.

[0059] “alkyl” means contains only hydrogen and carbon atoms with no hetero atoms.

[0060] By “reaction mixture” we mean the composition in the polymerization reactor which contains at least water, alkylsulfosuccinate and fluoromonomer.

[0061] A polymerization reaction in accordance with the present invention may be carried out by charging a reactor with water (preferably deionized water), at least one surfactant, at least one fluoromonomer and optionally, a chain-transfer agent and / or an antifoulant. Air may be purged from the reactor prior to the introduction of the fluoromonomer. Water generally is added to the reactor before bringing the reactor to the desired starting temperature, but the other materials may be added before or after bringing the reactor to temperature. At least one radical initiator is added to start and maintain the polymerization. The radical initiator is not added into the polymerization reaction until after monomer has been introduced into the system. Additional monomer may be optionally added to replenish monomer that is consumed, and the other materials may be optionally added during the course of the polymerization to maintain the reaction and control the final product properties.

[0062] Surfactant

[0063] A ‘surfactant’ is a type of molecule that has both hydrophobic and hydrophilic portions, which allow it to stabilize and disperse hydrophobic molecules and aggregates of hydrophobic molecules in aqueous systems.

[0064] The surfactants of the invention for fluoropolymer synthesis to the present invention comprise alkylsulfosuccinate.

[0065] In this invention, a representative sulfosuccinate has the general structure: X O O R R O21O Y

[0066] Where X and Y are SO3M or H, independently. Wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion. With the proviso that X and Y cannot both be H, simultaneously.

[0067] Where R1 can be H, an alkali metal ion, ammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising from 1 to 12 carbon units, preferably 3 to 10 carbon units, either branched or linear. R2 can be equal to R1 or H or a different alkyl moiety having from 1 to 12 carbon units, preferably 3 to 10 carbon units. With the proviso that at least one of R1 and R2 is an alkyl moiety.

[0068] When R1 or R2 is a alkyl moiety comprising from 1 to 12 carbon units, preferably 3 to 10 carbon units, it is preferable that R1 or R2 contains at least 1 branch, or at least two branches. Branching (Branches) means at least 1 secondary carbon exists in the alkyl moiety. For example, sodium bis(1,3- dimethyl butyl) sulfosuccinate contains two branching methyl groups (two branches) on a butyl chain.

[0069] In some embodiments R1 can be H, an alkali metal ion, ammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising from 1 to 8 carbon units, preferably 3 to 8 carbon units, either branched or linear. R2 can be equal to R1 or H or a different alkyl moiety having from 1 to 8 carbon units, preferably 3 to 8 carbon units. With the proviso that at least one of R1 and R2 is an alkyl moiety. The alkyl moiety may be comprise branches.

[0070] In some embodiments R1 can be H, an alkali metal ion, ammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising from 1 to 6 carbon units, preferably 3 to 6 carbon units, either branched or linear. R2 can be equal to R1 or H or a different alkyl moiety having from 1 to 6 carbon units, preferably 3 to 6 carbon units. With the proviso that at least one of R1 and R2 is an alkyl moiety. The alkyl moiety may be comprise branches.

[0071] Branched alkylsulfosuccinates are preferred over linear alkylsulfosuccinates.

[0072] The alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass. The alkylsulfosuccinate can have a critical micelle concentration in water of at least 0.10 mass %, or at least 0.50 mass %, or at least 1.0 mass %, or at least 1.2 mass % and less than 8.0 mass percent.

[0073] Surfactant may be added to the reactor before initiation, additional amounts of the surfactant may optionally be added during the reaction, after the reaction is complete, or at any point while processing the latex.

[0074] Surfactant quantities can range from 50 ppm to 2500, more preferably between 50 ppm and 2000 ppm, 300 ppm to 1500 ppm, based on monomer added to the reaction.

[0075] Some examples of alkylsulfosuccinate useful in the present invention include dipropyl sulfosuccinate, di-isopropyl sulfosuccinate, dibutyl sulfosuccinate, di-isobutyl sulfosuccinate, di-secbutyl sulfosuccinate, diamyl sulfosuccinate, bis(1-methyl butyl) sulfosuccinate, bis (2-methyl butyl) sulfosuccinate, bis(3-methyl butyl) sulfosuccinate, bis(1,3-dimethyl butyl) sulfosuccinate, bis (2,3-dimethyl butyl) sulfosuccinate, bis(1,2,2-trimethyl propyl) sulfosuccinate, bis (1,1,2-trimethyl propyl) sulfosuccinate, bis(ethyl hexyl) sulfosuccinate or a salt thereof. Combinations of any of these may be used as well. For easy availability and more favorable polymerization rate, bis(ethyl hexyl) sulfosuccinate and bis(1,3-dimethyl butyl) sulfosuccinate or their salts are preferred. Ammonium, sodium, or potassium alkylsulfosuccinate salts are preferred.

[0076] Generally speaking, lower concentrations of surfactant are preferred in order to avoid inhibition of the desired fluoromonomer polymerization reaction. For example, in various embodiments of the invention, the surfactant concentration in the reaction medium is less than 1000 ppm, less than 800 ppm, less than 600 ppm, or less than 500 ppm, based on the total weight of monomer added in the reaction.

[0077] In one embodiment of the invention, no type of surfactant other than the alkylsulfosuccinate is employed in the fluoromonomer polymerization process. In particular, the present invention provides a method for polymerizing fluoromonomers in which no or essentially no fluorinated surfactant is present during polymerization. However, in other embodiments of the invention, relatively minor amounts of one or more surfactants other than alkylsulfosuccinate are utilized. Preferably any other surfactant is non-fluorinated. Generally speaking, at least 50%, at least 75% or at least 90% by weight of the total amount of surfactant employed in the process is alkylsulfosuccinate.

[0078] Fluoromonomers

[0079] The term "fluoromonomer" or the expression "fluorinated monomer" means a polymerizable alkene which contains at least one fluorine atom, fluoroalkyl group, or fluoroalkoxy group attached to the double bond of the alkene that undergoes polymerization. The term "fluoropolymer" means a polymer formed by the polymerization of at least one fluoromonomer, and it is inclusive of homopolymers, copolymers, terpolymers and higher polymers which are thermoplastic in their nature, meaning they are capable of being formed into useful pieces by flowing upon the application of heat, such as is done in molding and extrusion processes. The thermoplastic polymers typically exhibit a crystalline melting point.

[0080] This invention claims the synthesis of fluorinated copolymers comprising a fluorinated ethylenic monomer. The fluorinated ethylenic monomer is selected from the group comprising: vinylidene fluoride (VDF), tetrafluoroethylene (TFE), trifluoroethylene (TrFE), chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), vinyl fluoride (VF), hexafluoroisobutylene (HFIB), perfluorobutylethylene (PFBE), pentafluoropropene, 3,3,3-trifluoro-1-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 perfluorinated vinyl ethers, fluorinated dioxoles, partially- or per-fluorinated alpha olefins of C4 and higher, partially- or per-fluorinated cyclic alkenes of C3 and higher, and combinations thereof. one or more of partly or fully fluorinated alpha-olefins such as 3,3,3- trifluoro-l-propene, 1,2,3,3,3-pentafluoropropene, 3,3,3,4,4-pentafluoro-l-butene, and hexafluoropropene, the partly fluorinated olefin hexafluoroisobutylene, perfluorinated vinyl ethers, such as perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoro-n-propyl vinyl ether, and perfluoro-2-propoxypropyl vinyl ether, fluorinated dioxoles, such as perfluoro(1,3-dioxole) and perfluoro(2,2- dimethy1-1,3- dioxole), allylic, partly fluorinated allylic, or fluorinated allylic monomers, such as 2- hydroxyethyl allyl ether or 3- allyloxypropanediol, and ethene or propene.

[0081] Fluoropolymers made by the practice of the present invention include the products of polymerization of the fluoromonomers listed above, for example, the homopolymer made by polymerizing vinylidene fluoride (VDF) by itself.

[0082] Copolymers, terpolymers and higher degree polymers of the fluoromonomers listed above, such as for example a higher degree polymer of vinylidene fluoride, may also be produced Copolymers, terpolymers and higher polymers of vinylidene fluoride may be made by selecting, for example, one or more additional monomers from the group which includes, for example, Copolymers made by the process of the invention include the copolymers of VDF with TFE, HFP, or trifluoroethylene. Preferred copolymers may be those which comprise from about 75 to about 99 weight percent VDF, and correspondingly comprise from about 1 to about 25 weight percent of comonomer. Example comonomers include, but are not limited to, TFE, HFP, or trifluoroethylene.

[0083] In embodiments which provide a VDF copolymer, the vinylidene fluoride units may comprise greater than or equal to 75 percent of the total weight of all the monomer units in the copolymer, and more preferably, comprise greater than 80 percent of the total weight of the units.

[0084] In some embodiments which provide a VDF copolymer the comonomer unit comprises HFP.

[0085] Initiators

[0086] The term "initiator" and the expressions "radical initiator" and "free radical initiator" refer toa chemical that is capable of providing a source of free radicals, either induced spontaneously, or by exposure to heat or light. Examples of suitable initiators include, but are not limited to, persulfate salts, peroxydicarbonates and azo compounds. “Initiators” do not include redox systems for thisinvention. The term "radical" and the expression "free radical" refer toa chemical species thatcontains at least one unpaired electron. The radical initiator is added to the reaction mixture in an amount sufficient to initiate and maintain the polymerization reaction rate. The order of addition may vary according to the desired process and latex emulsion characteristics.

[0087] Radical initiators suitable for use according to the invention are compounds, or combinations of compounds, that are capable of providing a source of free radicals, either spontaneously or by exposure to heat or light. The radical initiator is added to the reaction mixture in an amount sufficient to initiate and maintain the polymerization reaction at a desired reaction rate. Suitable non-limitingclasses of initiators include persulfate salts, azo compounds, all of which are well known in the art. Redox systems are excluded from this invention. As used herein, the term "ionic initiator" means a radical initiator that includes at least one salt containing a metal cation and / or an ammonium or substituted ammonium cation. Examples and typical use conditions of the various classes of initiator will now be discussed.

[0088] The radical initiator may comprise a persulfate salt, such as sodium persulfate, potassium persulfate, or ammonium persulfate. The amount of persulfate salt added to the reaction mixture (based upon the total weight of monomer added to the reaction mixture) is typically from about 0.005 to about 1.0 wt%.

[0089] The radical initiator may alternatively comprise an azo initiator, such as 2,2'- azobis(2- methylpropionamidine) dihydrochloride.

[0090] Chain-Transfer Agents

[0091] Chain-transfer agents can optionally be added to the polymerization to regulate the molecular weight of the product. They may 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 added to the polymerization reaction is preferably from about 0.01 to about 5 weight percent, more preferably from about 0.02 to about 2 weight percent based on the total weight of monomer added to the reaction mixture.

[0092] Oxygenated compounds such as alcohols, carbonates, ketones, esters, and ethers may serve as chain-transfer agents. Examples of oxygenated compounds useful as chain-transfer agents include isopropyl alcohol, as described in U.S. Patent 4,360,652. Other classes of compounds which may serve as chain-transfer agents in the polymerization of halogen- containing monomers include, for example, halocarbons and hydrohalocarbons, such as chlorocarbons. Alkanes such as ethane and propane may also function as chain-transfer agents. Any chain transfer known in the art to be used in the polymerization of halogen-containing monomers, particularly fluoromonomers may be used. In some embodiments. Ethane, propane, ethyl acetate may serve as chain-transfer agents in the polymerization of halogen-containing monomers.

[0093] Buffering Agent

[0094] The reaction mixture may optionally contain a buffering agent to maintain a controlled pH throughout the polymerization reaction. The pH is preferably controlled within the range of from about 2 to about 8, to minimize undesirable color development in the product. Buffering agents known in the art may be used.

[0095] Antifoulant

[0096] Antifoulants may optionally be added to the polymerization process. Antifoulants known in the art may be used. The addition of a paraffin wax or hydrocarbon oil to the reaction serves as an antifoulant to minimize or prevent polymer adhesions to the reactor components. Any long chain saturated hydrocarbon wax or oil can perform this function.

[0097] Polymerization Conditions

[0098] The temperature of the polymerization can vary depending on the characteristics of the initiator used. Suitable temperatures are typically between about 60° and 160° C, and most conveniently it is between 60° and 145° C or between 60° and 130° C, and most preferably from 60° and 125° C. The pressure of the polymerization can vary depending on the capabilities of the reaction equipment, the initiator system chosen, and the monomer selection. Suitable pressures of the polymerization are typically between 280 and 20,000 kPa, and most conveniently it is between can be between about 2000 and 20,000 kPa, preferably between 2,000 and 11,000 kPa, and most preferably from 2750-8000 kPa. The polymerization occurs under stirring or agitation. The stirring may be constant, or may be varied to optimize process conditions during the course of the polymerization.

[0099] According to one embodiment of the process of the invention, a pressurized polymerization reactor equipped with a stirrer and heat control means is charged with water, preferably deionized water, one or more alkylsulfosuccinates in accordance with the invention and at least one fluoromonomer. The reaction mixture may optionally contain one or more of an antifoulant and a chain-transfer agent for molecular weight regulation of the polymer product. Other materials may be added to the process such as, for example, initiators and buffering agents, to initiate and maintain necessary conditions for the polymerization reaction.

[0100] Prior to introduction of the monomer or monomers, air is preferably removed from the reactor in order to obtain an oxygen-free environment for the polymerization reaction. The reactor may be purged with a neutral gas such as, for example, nitrogen or argon.

[0101] Initiator is not added into the polymerization reaction until after monomer has been introduced into the system.

[0102] In another embodiment, a surfactant other than alkylsulfosuccinate is added to the reactor prior to initiation of polymerization. The alkylsulfosuccinate will be the major surfactant used, meaning the alkylsulfosuccinate will be greater than 50%wt of total surfactant in the polymerization reaction.

[0103] The order in which the polymerization components are assembled may be varied. In one embodiment, at least a portion of the alkylsulfosuccinate is present in the reaction mixture prior to the initiation of the polymerization of the fluoromonomer. An additional amount of alkylsulfosuccinate may be fed to the reactor during the reaction.

[0104] In one embodiment, water, alkylsulfosuccinate, fluoromonomer, and optionally antifoulant, chain transfer agent, and / or buffer are charged to the reactor, the reactor is heated to the desired reaction temperature. An initiator is added to the reaction mixture to initiate the polymerization reaction. Addition amounts of fluoromonomer(s) is (are) then fed into the reactor, preferably at a rate which provides a constant pressure. Other variations for fluoropolymer polymerization processes are contemplated, as known in the art.

[0105] The fluoromonomer feed is terminated when the desired weight of monomer has been fed to the reactor. Additional radical initiator is optionally added, and the reaction is allowed to react out for a suitable amount of time. The reactor pressure drops as the monomer within the reactor is consumed.

[0106] Upon completion of the polymerization reaction, the reactor is brought to ambient temperature and the residual unreacted monomer is vented to atmospheric pressure. The resulting product of the polymerization reaction is a fluoropolymer latex. The latex comprises or consists of a mixture of the reaction components and products, i.e., water, alkylsulfosuccinate, initiator (and / or decomposition products of the initiator) and fluoropolymer. Generally, the latex contains from about 10 to about 60 weight percent polymer solids, preferably from 20 to 60 weight percent solids. The polymer in the latex is in the form of small particles having a weight average particle size range of from about 10 nm to about 500 nm, preferably from 10 to 350 nm, and more preferably from 25 to 300 nm.

[0107] The polyvinylidene fluoride composition of the then invention comprises a polyvinylidene fluoride polymer and from 50 ppm to 2500 of one or more alkylsulfosuccinates based on polyvinylidene fluoride weight, wherein the polyvinylidene fluoride polymer comprises greater than 75 wt% VDF monomer units and the weight average particle size of said polyvinylidene fluoride polymer is between 10 and 350 nm, wherein the one or more alkylsulfosuccinate has the formula X O O R R O21O Y where X = SO3M or H, Y = SO3M or H, wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium or alkaline earth metal ion, with the proviso that X and Y cannot simultaneously be H; where R1 and R2 are, independently H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising 1 to 12 carbon units, preferably 3 to 10 carbon units, with the proviso that at least one of R1 and R2 is an alkyl moiety, and wherein the one or more alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass%. The critical micelle concentration in water can be at least 0.50 wt%, or can be at least 1.0wt%, or can be at least 1.2 wt %.

[0108] Product Handling

[0109] The product of the polymerization is a latex which can be used in that form, usually after filtration of solid byproducts from the polymerization process, or can be coagulated to isolate the solids, which may then be washed and dried. For use in latex form, the latex can be stabilized by the addition of further surfactant, which may be the same surfactant present during polymerization or a different surfactant from that present during polymerization. For example, the further surfactant may be an alkylsulfosuccinate or another type of ionic or non-ionic surfactant. For a solid product, the latex may be coagulated mechanically or by the addition of salts or acids, and then isolated by well-known means such as by filtration. Once isolated, solid product can be purified by washing or other techniques, and it may be dried for use as a powder, which can be further process into granules.

[0110] The resulting polymers of the present invention have applications in coatings, battery separator coatings and membranes.

[0111] 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. EXAMPLES

[0112] General Procedure 1 – Latex Synthesis:

[0113] An autoclave equipped with circulating jacket and mechanical agitation is charged with deionized water and alkylsulfosuccinate as surfactant. This water charge is deoxygenated by pressurization of the reactor to 60 psig with ultra-pure nitrogen, holding at that pressure for 5 min with agitation, then venting to 0 psig. This cycle is repeated an additional 2 times. At that point the optional ethyl acetate is admitted to the reactor. Agitation of the reactor contents is commenced at 72 rpm. The reaction mixture temperature is then increased to the desired value. Persulfate initiator solution is prepared with buffering agent. Once the desired temperature has stabilized, vinylidene fluoride (VDF) and optional comonomer is admitted to 650 psig and agitation is started at the target rate. The reaction is commenced by admission of initiator solution initial charge, followed by a slow-feed of initiator solution to a reaction rate of no more than 1300 mL / hr monomer consumption, to maintain the reaction pressure and temperature with a target of a total reaction time of between 80 min. to 240 min. VDF (and / or comonomer) is optionally admitted via high-pressure syringe or reciprocating pump to maintain the 650psi reaction pressure. Upon reaching the preset total monomer addition of ~20-60 wt.% of total mass in reactor, monomer admission is stopped and the remaining monomer in the reactor is allowed to continue to react for 20 to 40 min with concurrent pressure decrease. Following that time, the agitation is halted, reactor cooled to room temperature and vented. Product latex is discharged from the reactor through a bottom-drain. Latex solids is measured in duplicate. Percent solids of the polymer does not include coagulum and is determined gravimetrically by difference in weight before and after drying.

[0114] Latex solids content are measured gravimetrically in duplicate using a moisture analyzer apparatus such as Mettler-Toledo HX204, and the average is reported. In the moisture analyzer, the polymer latex sample is weighted and heated until up to 115C to dry the sample, untilthe weight is constant, the weight before and after drying is used to determine the percent solids. Percent coagulum is determined gravimetrically by difference in mass of the mesh screen before and after collection of coagulum (after drying of the coagulum- dried in an oven at 60C for 16 hours). Percentage coagulumis calculated as product produced that would not pass through a mesh screen (namely a cheese cloth - Cotton, Bleached Grade 90, with 44X36 threads per square inch from Idealfold Model: BIDF4436360) under gravimetric filtration divided by total monomer fed to reactor.

[0115] General Procedure 2 – Melt Viscosity Measurement:

[0116] Approximately 15g of dried product, either as coarse powder from oven-drying or as fine powder from spray-drying is added to the pre-heated (232C) sample cylinder of the capillary rheometer (Dynisco Inc., model LCR-7000) equipped with a 1.0mm ID x 10mm length die. Melt viscosity are according to ASTM D3835 by capillary rheometry at 232°C and 100 sec-1.

[0117] Table 1: Conditions and properties of polymerizations in the presence of sulfosuccinate surfactant.B = Sodium 1,4-bis(ethyl-hexyl) ester sulfosuccinate In example 5, 24.0g ethyl acetate was added to the reactor before pressurization. In example 6, 12.0g ethyl acetate was added to the reactor before pressurization. In example 7, 15.0g ethyl acetate was added to the reactor before pressurization.

[0118] Example 10:

[0119] A 2.0 gallon-volume autoclave equipped with circulating jacket and mechanical agitation was charged with 3000g deionized water and 2.0g sodium bis(1,3-dimethyl butyl) sulfosuccinate (10 ppm based on monomer feed). The autoclave was deoxygenated by pressurization of the reactor to 60 psig with ultra-pure nitrogen, holding at that pressure for 5 min with agitation, then venting to 0 psig. This cycle is repeated an additional 2 times. The reactor was sealed and agitated at 72 rpm and heated to 125 °C. Once at 125 °C, 150 mL of 1.0wt% potassium persulfate (KPS) and 1.0wt% sodium acetate (SAT) solution was fed to the reactor. Throughout the reaction, the feed rate of KPS / SAT was kept between 100-150mL / h. VDF was fed to maintain reactor pressure at 650 psig. Feeds were continued until 2000 g VDF was delivered to the reactor, then all feeds were halted. The reactor was held at 83 °C for twentyminutes. The reactor was cooled to 40 °C and vented to atmospheric pressure. Product was discharged from the reactor. Particle size = 183 nm, %Coagulum = 1.5.

[0120] This example shows that the polymerization can be run at higher temperatures (for example 125C without gelling of the reaction medium.

[0121] Counter Example 11: Amount of Surfactant

[0122] A 2.0 gallon-volume autoclave equipped with circulating jacket and mechanical agitation was charged with 4000g deionized water and 8.10g sodium bis(1,3-dimethyl butyl) sulfosuccinate. (3000 ppm based on total monomer feed). The auto clave was deoxygenated by pressurization of the reactor to 60 psig with ultra-pure nitrogen, holding at that pressure for 5 min with agitation, then venting to 0 psig. This cycle is repeated an additional 2 times. The reactor was sealed and agitated at 72 rpm and heated to 83 °C. Once at 83 °C, 150 mL of 1.0wt% potassium persulfate (KPS) and 1.0wt% sodium acetate (SAT) solution was fed to the reactor. The reactor was pressurized to 650 psig with vinylidene fluoride. A feed of aqueous solution was started at 100.0 mL / h. Throughout the reaction, the feed rate of KPS / SAT was kept between 100-300mL / h. VDF was fed to maintain reactor pressure at 650 psig. Feeds were continued until 2700 g VDF was delivered to the reactor, then all feeds were halted. The reactor was held at 83 °C for twenty minutes. The reactor was cooled to 40 °C and vented to atmospheric pressure. Product was discharged from the reactor. The product was entirely coagulated and could not flow.

[0123] This counter example shows that the invention fails at 0.3 wt % surfactant (in terms of by wt% coagulum) Too much surfactant results in coagulation.

[0124] Counter Example 12: Surfactant with CMC less than 0.1 mass percent

[0125] A 2.0 gallon-volume autoclave equipped with circulating jacket and mechanical agitation was charged with 3000g deionized water and 2.00g sodium 1,4-bis(C11-14-isoalkyl esters, C13-rich) sulfosuccinate. (1000 ppm based on total monomer feed). The auto clave was deoxygenated by pressurization of the reactor to 60 psig with ultra-pure nitrogen, holding at that pressure for 5 min with agitation, then venting to 0 psig. This cycle is repeated an additional 2 times. The reactor was sealed and agitated at 72 rpm and heated to 83 °C. The reactor was pressurized to 650 psig with vinylidene fluoride. To the reactor, 150g of a solution of 1 wt% potassium persulfate (KPS) and 1 wt% sodium acetate (SAT) buffer was added. A feed of the 1wt% KPS / SAT was initiated at 100.0 mL / h. The feed rate of KPS / SAT was increased to 600mL / h, over 2 hours. No additional VDF was fed to the reactor to maintain pressure at 650, demonstrating that polymerization was slow to initiate or not occurring. After feeding 795 g of the 1 wt% KPS / SAT solution the reactor was cooled to 40 °C and vented to atmospheric pressure. A semi-transparent product was discharged with solids content of 6.39%. demonstrating low yield and limited productivity. The presence of a surfactant with a CMC less than 0.1 mass percent was insufficient and generating an emulsion latex with high amounts of fluoropolymer.

[0126] Counter Example 13: Un-branched surfactant CMC lower than 0.1 mass percent

[0127] A 2.0 gallon-volume autoclave equipped with circulating jacket and mechanical agitation was charged with 3000g deionized water and 2.00g sodium 1,4-bis(hexyl) sulfosuccinate. (1000 ppm based on total monomer feed). The auto clave was deoxygenated by pressurization of the reactor to 60 psig with ultra-pure nitrogen, holding at that pressure for 5 min with agitation, then venting to 0 psig. This cycle is repeated an additional 2 times. The reactor was sealed and agitated at 72 rpm and heated to 83 °C. The reactor was pressurized to 650 psig with vinylidene fluoride. To the reactor, 150g of a solution of 1 wt% potassium persulfate (KPS) and 1 wt% sodium acetate (SAT) buffer was added. A feed of the 1wt% KPS / SAT was initiated at 100.0 mL / h. The feed rate of KPS / SAT was varied between 25 mL / hr to 200 mL / hr, in an attempt to keep the reaction demand for additional VDF near 1200 mL / hr. After feeding 346g of the 1 wt% KPS / SAT solution the feed of initiator and VDF were ended. The reactor was cooled to 40 °C and vented to atmospheric pressure. Product was discharged from the reactor. The product was entirely coagulated and could not flow. The material had a melt viscosity of 53 kP at 100 s-1.

[0128] While the embodiments of the present disclosure have been described with particular reference to certain embodiments thereof, it will be understood that changes and modifications may be made by those of ordinary skill within the scope and spirit of the following claims.

Claims

CLAIMS 1. A process of producing an aqueous latex of polyvinylidene fluoride by emulsion polymerization in the absence of a fluorinated surfactant comprising: a. charging a polymerization reactor with deionized water and one or more alkylsulfosuccinates, b. optionally adding one or more of chain transfer agent, buffer, paraffin antifoulant, c. feeding monomer comprising VDF to the reactor until the pressure reaches at least 280 kPa thereby forming an reaction mixture, d. feeding an initiator to the reaction mixture, e. polymerizing said fluoromonomer to produce an aqueous fluoropolymer latex wherein the one or more alkylsulfosuccinate has the formulawhere X = SO3M or H, Y = SO3M or H, wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium or alkaline earth metal ion, with the proviso that X and Y cannot simultaneously be H, where R1 and R2 are, independently H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising 1 to 12 carbon units, preferably 3 to 10 carbon units, with the proviso that at least one of R1 and R2 is an alkyl moiety, wherein the one or more alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass% and wherein the one or more alkylsulfosuccinate is added in an amount of from 50 ppm to 2500 ppm, based on weight of fluoromonomer in the process, and wherein the amount of vinylidene fluoride monomer based on total fluorinated monomer used in the process comprises at least 75wt%.

2. The process of claim 1, wherein the one or more alkylsulfosuccinate has a critical micelle concentration in water of at least 0.50 mass percent, or at least 1.0 mass percent, or at least 1.2 mass %.

3. The process of any one or more of claims 1 to 2, wherein at least one of R1 and R2 comprises a alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least one branch.

4. The process of any one or more of claims 1 to 2, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units, wherein said alkyl moiety comprises at least two branches.

5. The process of any one or more of claims 1 to 4, wherein R1 and R2 are the same.

6. The process of any one or more of claims 1 to 2, wherein the alkylsulfosuccinate comprises at least one of dipropyl sulfosuccinate, di-isopropyl sulfosuccinate, dibutyl sulfosuccinate, di-isobutyl sulfosuccinate, di-secbutyl sulfosuccinate, diamyl sulfosuccinate, bis(1-methyl butyl)sulfosuccinate, bis (2-methyl butyl) sulfosuccinate, bis(3-methyl butyl) sulfosuccinate, bis(1,3- dimethyl butyl) sulfosuccinate, bis (2,3-dimethyl butyl) sulfosuccinate, bis(1,2,2-trimethyl propyl) sulfosuccinate, bis (1,1,2-trimethyl propyl) sulfosuccinate, bis(ethyl hexyl) sulfosuccinate or a salt thereof.

7. The process of any one or more of claims 1 to 2, wherein the alkylsulfosuccinate comprises an salt of bis(1,3-dimethyl butyl) sulfosuccinate.

8. The process of any one or more of claims 1 to 7, wherein the alkylsulfosuccinate is added to the aqueous reaction medium both before addition of initiator.

9. The process of any one or more of claims 1 to 8, wherein the one or more alkylsulfosuccinate is added to the reaction mixture in an amount of between 50 ppm and 2000 ppm, or 300 ppm to 1500 ppm, based on weight of vinylidene fluoride monomer used in the process.

10. The process of any one or more of claims 1 to 9, wherein chain transfer agent is added to the polymerization reaction.

11. The process of claim 10, wherein chain transfer agent comprises ethyl acetate.

12. The process of any one or more of claims 1 to 11, wherein the monomer does not comprise a crosslinkable group.

13. The process of any one or more of claims 1 to 12, wherein the monomer comprises at least one fluorinated monomer, in addition to the vinylidene fluoride monomer, selected from the group consisting of tetrafluoroethylene (TFE), trifluoroethylene, chlorotrifluoroethylene (CTFE), hexafluoropropene (HFP), vinyl fluoride, hexafluoroisobutylene, perfluorobutylethylene (PFBE), pentafluoropropene, 3,3,3-trifluoro-1- propene, 2-trifluoromethyl-3,3,3-trifluoropropene, fluorinated vinyl ethers, fluorinated allyl ethers, non-fluorinated allyl ethers, fluorinated dioxoles, and the combinations.

14. The process of any one or more of claims 1 to 12, wherein the monomer comprises hexafluoropropene.

15. The process of any one or more of claims 1 to 14, wherein said initiator is a persulfate salt, selected from the group consisting of sodium persulfate, potassium persulfate, or ammonium persulfate, the amount of persulfate salt added to the reaction mixture, based upon the total weight of monomer added to the process, being from 0.005 to 1.0 weight percent.

16. The process of any one or more of claims 1 to 15, wherein the fluoropolymer is a copolymer of vinylidene fluoride and a second monomer, wherein the copolymer is from about 75 to about 99 weight percent vinylidene fluoride and from about 1 to about 25 weight percent the second monomer based on total fluoromonomer in the polymer.

17. The process of any one or more of claims 1 to 16, wherein said latex has a solid content of from 10 to 60 weight percent, preferably of 15 to 45 weight percent.

18. The process of any one or more of claims 1 to 17, wherein the process comprises adding at least one component selected from the group consisting of chain-transfer agents, buffering agents, antifoulants, and mixtures thereof.

19. A polyvinylidene fluoride latex comprising a polyvinylidene fluoride polymer and from 50 ppm to 2500 ppm of one or more alkylsulfosuccinates based on total polyvinylidene fluoride polymer weight, wherein polyvinylidene fluoride polymer comprises greater than 75 wt% VDF monomer units and the weight average particle size of said polyvinylidene fluoride polymer is between 10 and 350 nm, wherein the one or more alkylsulfosuccinate has the formulawhere X = SO3M or H, Y = SO3M or H, wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium or alkaline earth metal ion, with the proviso that X and Y cannot simultaneously be H, where R1 and R2 are, independently H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising 1 to 12 carbon units, preferably 3 to 10 carbon units, with the proviso that at least one of R1 and R2 is an alkyl moiety, and wherein the one or more alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass%.

20. The polyvinylidene fluoride latex of claim 19, wherein the one or more alkylsulfosuccinate has a critical micelle concentration in water of at least 0.50, or at least 1.0, or at least 1.2 wt %.

21. The polyvinylidene fluoride latex of claim 19 or 20, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least one branch.

22. The polyvinylidene fluoride latex of claim 19 or 20, wherein at least one of R1 and R2 comprises a alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least two branches.

23. The polyvinylidene fluoride latex of claim 19, wherein the alkylsulfosuccinate comprises at least one of dipropyl sulfosuccinate, di-isopropyl sulfosuccinate, dibutyl sulfosuccinate, di-isobutyl sulfosuccinate, di-secbutyl sulfosuccinate, diamyl sulfosuccinate, bis(1-methyl butyl) sulfosuccinate, bis (2-methyl butyl) sulfosuccinate, bis(3-methyl butyl) sulfosuccinate, bis(1,3- dimethyl butyl) sulfosuccinate, bis (2,3-dimethyl butyl) sulfosuccinate, bis(1,2,2-trimethyl propyl) sulfosuccinate, bis (1,1,2-trimethyl propyl) sulfosuccinate, bis(ethyl hexyl) sulfosuccinate or a salt thereof.

24. The polyvinylidene fluoride latex of claim 19, wherein the alkylsulfosuccinate comprises at comprises a salt of bis(1,3-dimethyl butyl) sulfosuccinate.

25. The polyvinylidene fluoride latex of any one or more of claims 19 to 24, wherein alkylsulfosuccinate comprises from between 50 ppm and 2000 ppm, or from between 300 ppm to 1500 ppm of one or more alkylsulfosuccinates based on total polyvinylidene fluoride polymer weight.

26. The polyvinylidene fluoride latex of any one or more of claims 19 to 25, wherein the polymer comprises hexafluoropropene monomer units.

27. A polyvinylidene fluoride composition comprising a polyvinylidene fluoride polymer and from 50 ppm to 2500 of one or more alkylsulfosuccinates based on polyvinylidene fluoride weight, wherein the polyvinylidene fluoride polymer comprises greater than 75 wt% VDF monomer units and the weight average particle size of said polyvinylidene fluoride polymer is between 10 and 350 nm, wherein the one or more alkylsulfosuccinate has the formulawhere X = SO3M or H, Y = SO3M or H, wherein M is H, an alkali metal ion, ammonium, alkylammonium, phosphonium or alkaline earth metal ion, with the proviso that X and Y cannot simultaneously be H, where R1 and R2 are, independently H, an alkali metal ion, ammonium, alkylammonium, phosphonium, alkaline earth metal ion, or an alkyl moiety comprising 1 to 12 carbon units, preferably 3 to 10 carbon units, with the proviso that at least one of R1 and R2 is an alkyl moiety, and wherein the one or more alkylsulfosuccinate has a critical micelle concentration greater than 0.1 mass% and less than 10.0 mass%.

28. The polyvinylidene fluoride composition of claim 27, wherein the one or more alkylsulfosuccinate has a critical micelle concentration in water of at least 0.50, or at least 1.0, or at least 1.2 wt %.

29. The polyvinylidene fluoride composition of claim 27 or 28 wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least one branch.

30. The polyvinylidene fluoride composition of claim 27 or 28, wherein at least one of R1 and R2 comprises an alkyl moiety comprising 3 to 10 carbon units wherein said alkyl moiety comprises at least two branches.

31. The polyvinylidene fluoride composition of claim 27 or 28, wherein the alkylsulfosuccinate comprises at least one of dipropyl sulfosuccinate, di-isopropyl sulfosuccinate, dibutyl sulfosuccinate, di-isobutyl sulfosuccinate, di-secbutyl sulfosuccinate, diamyl sulfosuccinate, bis(1-methyl butyl) sulfosuccinate, bis (2-methyl butyl) sulfosuccinate, bis(3-methyl butyl) sulfosuccinate, bis(1,3- dimethyl butyl) sulfosuccinate, bis (2,3-dimethyl butyl) sulfosuccinate, bis(1,2,2-trimethyl propyl) sulfosuccinate, bis (1,1,2-trimethyl propyl) sulfosuccinate, bis(ethyl hexyl) sulfosuccinate or a salt thereof.

32. The polyvinylidene fluoride composition of claim 27 or 28, wherein the alkylsulfosuccinate comprises a salt of bis(1,3-dimethyl butyl) sulfosuccinate.

33. The polyvinylidene fluoride latex of any one or more of claims 27 to 32 containing alkylsulfosuccinate comprising from 50 ppm to 2000 ppm, or from 300 ppm to 1500 ppm of one or more alkylsulfosuccinates based on total polyvinylidene fluoride polymer weight.

34. The polyvinylidene fluoride composition of any one or more of claims 27 to 33, wherein the polyvinylidene fluoride polymer comprises hexafluoropropene monomer units.

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