VDF CONTAINING A (CO)POLYMER HAVING A HIGH MOLECULAR MASS BY USING A NEW PRECIPITATION POLYMERIZATION PROCESS

Abstract

The invention describes a new PVDF polymer and the precipitation polymerization process for manufacturing the vinylidene fluoride-based polymer or copolymer.

Description

Description Title of the invention: VDF CONTAINING A (CO)POLYMER HAVING A HIGH MOLECULAR MASS BY USE OF A NEW POLYMERIZATION PROCESS BY PRECIPITATION Scope of the invention

[0001] = The invention exposes a VDF containing a (co)polymer having a high mo- mass lecular and a polymer manufacturing process.

[0002] — Background of the invention

[0003] — Vinylidene fluoride polymers or copolymers are polymers that can to be implemented in a molten state, which are prepared by several different processes of polymerization.

[0004] — Vinylidene fluoride-based polymers are semi-crystalline polymers containing both crystalline and amorphous regions. The relationship between the amorphous and crystalline regions, as well as the amount of crystalline phase and dif- Different crystalline phases affect the properties of the polymer and determine the ap- Final plications of a given resin composition. An increase in mass Molecular properties can increase strength and mechanical properties in the molten state. such as toughness and resistance to cracking under chemical stress.

[0005] — It is known in the prior art to obtain a high molecular weight PVDF by emulsion polymerization; for example, US 9202638 exposes a PVDF having a molten viscosity of 900 to 200 kP at 4 s, US 10559828 exposes a viscosity at the molten state of said fluorinated polymer, measured at a temperature of 232 °C and at a shear rate of 100 s-!, from 10 to 100 kP and US 8785580 exposes a co- PVDF polymer having a melt viscosity greater than 35 kP, with examples having a molten viscosity of 56 to 52 kP.

[0006] PVDF has several crystalline phases, called α, P, γ, Δ and ε phases, which can To be obtained through different processes / different implementation conditions. The PVDF usually forms the a phase from the molten state. In the a phase, the PVDF chains have a polarity and chain stacking in an anti- parallel. An antiparallel stacking leads to a nonpolar nature of the phase crystal a. The phase crystal | is usually formed by cold drawing of the phase crystal a. In the PB phase crystal, the PVDF chains have a polarity and a stacking in parallel formation. Consequently, the phase crystal | is the one that has the moment highest dipole, and is used for ferroelectric and other applications numerous other applications. The normal phase Y crystal is produced by treatment thermal conductivity of the phase a crystal. The phase y crystal has a polarity similar to that of the phase fB crystal. The beta crystal phase of PVDF has attracted considerable interest due to its piezoelectric properties. A high proportion of the B phase in PVDF is prepared either by customizing the polymer chain based on a copolymerization of vinylidene fluoride with a certain comonomer such as vinyl fluoride (VF), trifluoroethylene (TrFE), chlorotrifluoroethylene (CTFE), or by a second processing method or by post-treatment techniques such as temperature, pressure, cooling rate, and the application of shear forces. PVDF latex can be spray-dried to give a particle size of 1 µm to 30 µm. However, these particles do not contain a significant amount of the B phase. In contrast, the present invention makes it possible to obtain particles having an average precipitated particle size of 50 to 2,500 micrometers, consisting essentially of the beta phase. Description of the Figures Figure [Fig.1] shows a spray-dried powder particle obtained by a conventional emulsion process. Figure [Fig. 2] shows a powder particle obtained by a conventional suspension process. Figure [Fig. 3] shows a particle obtained by a precipitation process. Figure 4 shows primary particles obtained by a conventional emulsion process. Figure 5 presents primary particles obtained by a precipitation process, showing a raspberry-like morphology. Figure 6 shows an FTIR spectrum (with an alpha wave) obtained by conventional emulsion polymerization. Alpha phase signal: 974 cm⁻¹, 797 cm⁻¹, 766 emm⁻¹ Figure 7 is an FTIR spectrum (with a beta form) obtained by precipitation polymerization. Beta phase signal: 1275 cm⁻¹. Figure 8 shows a wide-angle X-ray diffraction (with an alpha shape) obtained by a conventional emulsion polymerization. The a phase shows more characteristic peaks at 26 = 17.66°, 18.30° and 26.56° than the diffractions in the planes respectively (1 O 0), (0 2 0) / (1 1 0), (0 2 1). Figure 9 shows a wide-angle X-ray diffraction (with a beta form) obtained by precipitation polymerization. The beta phase exhibits just a well-defined peak at 2π = 20.26°, relative to the sum of the diffraction at the (110) and (200) planes. Summary of the invention The invention describes a novel PVDF polymer and a precipitation polymerization process for manufacturing the polymer or vinylidene fluoride-based copolymer. The PVDF polymer essentially has a beta phase (as measured by the ratio of the peak intensities of the beta phase crystal: Ip:200n10) / [I'(020) + L4020)] greater than 5, a high melting point (greater than 165 °C), and exhibits a raspberry-like morphology. The polymer has potential applications in the production of components for lithium-ion batteries. Aspects of the invention Aspect 1: Poly(vinylidene fluoride) polymer characterized in that said polymer has a melting temperature between 165 °C and 175 °C, preferably from 168 °C to 174 °C, exhibits a raspberry morphology and a ratio of beta phase intensities (In(2oor10 / [eçonny + Luo20)] ) Greater than 5. Aspect 2: Poly(vinylidene fluoride) polymer according to aspect 1, the polymer having a melt viscosity of 53 to 150 kP at 100 s and of 900 to 3,500 kP at 4 s, Aspect 3: Poly(vinylidene fluoride) polymer according to any of aspects 1 or 2, the viscosity in 9 wt% NMP solution (measured at 3.36 / s) being at least 7,000 cP, preferably greater than 9,000 cP. Aspect 4: Poly(vinylidene fluoride) polymer according to any one of aspects 1 to 3, the delta H (first heating) being greater than 58 Jg. Aspect 5: Poly(vinylidene fluoride) polymer according to any one of aspects 1 to 4, the polymer comprising at least 97% by weight of vinylidene fluoride monomer units. Aspect 6: Poly(vinylidene fluoride) polymer according to any one of aspects 1 to 5, the polymer being a homopolymer. Aspect 7: Poly(vinylidene fluoride) polymer according to any one of aspects 1 to 5, the polymer comprising at least one non-fluorinated monomer. Aspect 8: Poly(vinylidene fluoride) polymer according to aspect 7, wherein at least one non-fluorinated monomer comprises at least one of acrylic acid (AA), carboxyethyl acrylate (CEA), and acryloyloxyethyl succinate (AES). Aspect 9: Poly(vinylidene fluoride) polymer according to any one of aspects 1 to 8, the polymer being in the form of precipitated particles having an average precipitated particle size in the range of 50 micrometers to 2,500 micrometers, preferably from 100 to 2,200 micrometers. Aspect 10: Poly(vinylidene fluoride) polymer according to any one of aspects 1 to 9, the ratio of intensities being greater than 6. Aspect 11: A precipitation polymerization process for producing a PVDF having a B phase, the process comprising the steps of introducing water into a reactor, purging said reactor with a gas to remove oxygen, and heating said reactor, introducing vinylidene fluoride and possibly a non-fluorinated monomer into said reactor to achieve the desired pressure, introducing an initiator solution into said reactor, possibly continuing to feed the initiator solution during polymerization, maintaining the polymerization reaction temperature constant between 50 °C and 70 °C during the reaction, and maintaining the pressure between 280 and 40,000 kPa, feeding monomer to maintain the pressure and continuing the polymerization reaction until the amount of VDF consumed reaches the predetermined value, venting the excess gas to the atmosphere, and recovering the precipitated polymer by collecting the solids that precipitated during the polymerization reaction. the quantity of initiator used for polymerization being at least 2000 ppm. Aspect 12: A process according to aspect 11, wherein the aqueous initiator solution comprises an inorganic persulfate. Aspect 13: A process according to any one of aspects 11 to 12, wherein the initiator comprises at least one of hydrogen peroxide, sodium persulfate, potassium persulfate or ammonium persulfate. Aspect 14: A process according to any one of aspects 11 to 13, wherein the temperature range is from 53 °C to 69 °C, preferably from 58 °C to 68 °C. Aspect 15: A process according to any one of aspects 11 to 14, wherein the amount of initiator is from 2,000 ppm to 10,000 ppm, preferably from 3,000 to 8,000 ppm, relative to the total monomer weight. Aspect 16: A process according to any one of aspects 11 to 15, in which no surfactant is added to the reactor. Aspect 17: Process according to any one of aspects 11 to 16, wherein the non-fluorinated monomer is fed at the beginning of the reaction and / or during the reaction. Aspect 18: A process according to any one of aspects 11 to 17, wherein the amount of non-fluorinated monomer added is 0.05 to 5 percent by weight, preferably 0.1 to 3 percent by weight relative to the total monomer used. Aspect 19: A process according to any one of aspects 11 to 18, wherein the non-fluorinated monomer comprises at least one non-fluorinated monomer selected from the group consisting of acrylic acid (AA), carboxyethyl acrylate (CEA) and acryloyloxyethyl succinate (AES). Aspect 20: Suspension composition for the production of a lithium-ion battery, comprising the poly(vinylidene fluoride) polymer according to any one of aspects 1 to 10, an active electrode material, a non-aqueous solvent and, optionally, an additive conferring electrical conductivity and / or a viscosity-modifying agent. Appearance 21: Suspended composition according to appearance 20, comprising: (a) the (b) poly(vinylidene fluoride) polymer in an amount of 0.5 to 5% by weight, preferably 0.5 to 3% by weight, relative to the total weight of (a) + (b) + (c); (b) an additive conferring electrical conductivity, in an amount of 0.5 to 5% by weight, preferably 0.5 to 3% by weight, relative to the total weight of (a) + (b) + (c); (c) an active electrode material in an amount of 90 to 99% by weight, preferably 95 to 99% by weight. Aspect 22: Electrode for lithium-ion battery obtained by applying the composition in suspension according to aspect 21 to a collector, and drying the coating. Aspect 23: Lithium-ion battery comprising the electrode according to aspect 22. Aspect 24: Article comprising the polymer poly(vinylidene fluoride) according to any one of aspects 1 to 10. Aspect 25: Process for producing a battery electrode comprising the steps of: to supply the poly(vinylidene fluoride) polymer according to any one of the Aspects 1 to 10, the polymer poly(vinylidene fluoride) is presented as form of precipitated particles having an average particle size of 50 micrometers to 2,500 micrometers, ii. combine the poly(vinylidene fluoride) polymer from i) with a solvent and an electrode material to provide a composition forming an electrode, with the poly(vinylidene fluoride) polymer dissolved in the solvent, iii. apply the electrode-forming composition to at least one surface of a electrically conductive substrate, and iv. evaporate the solvent in the electrode-forming composition to form a composite electrode layer on the electroconductive substrate. DETAILED DESCRIPTION OF THE INVENTION All references mentioned in this application are incorporated herein by reference. All percentages in a composition are percentages by weight unless otherwise stated. The term "polymer" is used to refer to both homopolymers and copolymers. "Copolymer" refers to a polymer having two or more different monomer units. Polymers can be linear, branched, star-shaped, comb-shaped, block-like, cross-linked, or have any other structure. Polymers can be homogeneous, heterogeneous, and can have a gradient distribution of comonomer units. The term "poly(vinylidene fluoride) polymer" ("PVDF") refers to a polymer formed by the polymerization of at least one monomeric vinylidene fluoride, and includes homopolymers, copolymers, terpolymers, and superior polymers of a thermoplastic nature, meaning that they are likely to be transformed into useful parts by casting after the application of heat, as is done in molding and extrusion processes. The invention describes a novel PVDF polymer and the process for manufacturing the vinylidene fluoride-based polymer by a precipitation polymerization process. The precipitation polymerization process / technique is based on the formation of polymer aggregates from precipitated polymer particles. The resulting polymer is in the form of porous particles composed of agglomerated non-porous primary particles, as can be observed under magnification (SEM) (which will be referred to in the invention as "precipitated particles"). In certain embodiments of the invention, the polymer is a vinylidene fluoride homopolymer having a high melting temperature (greater than 165 °C by DTA) and an exceptionally high melt viscosity, a high melting point, and predominantly a fi phase, detected by WAXD (wide-angle X-ray diffraction).Homopolymers and copolymers can be produced using the process of the invention. The invention can be used in battery applications, for electrodes and / or separators. The polymer of the invention exhibits excellent peel resistance in cathodic binders. The cathode produced using the polymer can be part of a lithium-ion battery. PRECIPITATION POLYMERIZATION REACTION The precipitation polymerization used in the invention is a heterogeneous polymerization process that initially begins as a homogeneous continuous-phase system. The polymer formed becomes insoluble after initiation and then undergoes precipitation. Precipitation occurs as part of the polymerization reaction and is not a post-polymerization step. No additives are added to initiate precipitation. The following technique is generally followed for the precipitation polymerization process. Deionized water, possibly a chain transfer agent, and possibly an antifouling agent are introduced into a reactor, followed by deoxygenation (removal of oxygen). After the reaction has reached the desired temperature, a monomer (vinylidene fluoride and possibly a non-fluorinated monomer) is introduced into the reactor to reach a predetermined pressure. When the desired reaction pressure is reached, an initiator solution or a combination of initiator solutions is added to start and maintain the polymerization reaction. After the desired level of one or more monomers has been introduced, the monomer supply is stopped. However, the introduction of the initiator may be interrupted or The reaction continues to consume the unreacted monomers. After stopping the introduction of the initiator, the reactor can be cooled, and stirring is stopped. The polymer precipitates during the polymerization process. The unreacted monomers can be vented to the atmosphere, and the precipitated polymer can be collected through a drain or other means. The precipitation polymerization process can be a batch, semi-continuous or continuous polymerization process. The reactor used for polymerization is a pressure polymerization reactor. The reactor is usually equipped with a stirrer and a temperature control device. Stirring can be constant, or it can be varied to optimize the process conditions during polymerization. The polymerization temperature can vary depending on the characteristics of the initiator used, but it is usually between 50 and 70 degrees Celsius. The preferred polymerization temperature is between 53 and 69 degrees Celsius, and more specifically between 58 and 68 degrees Celsius. The polymerization pressure can vary from 280 to 40,000 kPa, depending on the capabilities of the reaction equipment, the chosen initiator system, and the selected monomer. The preferred polymerization pressure is between 2,000 and 20,000 kPa, and especially between 3,500 and 11,000 kPa. SURFACTANT The process of the present invention is implemented without a surfactant. ATC A chain transfer agent (CTA) may optionally be added to the polymerization to regulate the molecular weight of the product. The chain transfer agent may be added to a polymerization in a single portion at the beginning of the reaction, or incrementally or continuously throughout the reaction. The amount and method of addition of the chain transfer agent depend on the activity of the particular chain transfer agent used and the desired molecular weight of the polymer product. The CTA is not required for the polymerization, but if used, the amount of chain transfer agent added to the polymerization reaction is preferably about 0.05 to about 5 percent by weight, and more specifically about 0.1 to about 2 percent by weight relative to the total weight of the monomer added to the reaction mixture.Examples of chain transfer agents that can be used in the present invention include, but are not limited to, oxygenated compounds such as alcohols, carbonates, ketones, esters, ethers, halocarbons, hydrohalogen hydrocarbons such as chlorocarbons, hydrochlorocarbons, chlorofluorocarbons, hydrochlorofluorocarbons; ethane, propane. Preferably, the chain transfer agent is propane or ethyl acetate. If desired, a paraffin-type antifouling agent can be used, although it is not preferred, and any long-chain saturated hydrocarbon oil or wax can be used. The paraffin loading in the reactor can be from 0.01% to 0.3% by weight relative to the total weight of monomers used. PRIMER The reaction can be initiated and sustained by adding a suitable initiator known to polymerize fluorinated monomers, including organic peroxides, inorganic peroxides, and hydrogen peroxide. Examples of common inorganic peroxides include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate. The amount of initiator required for precipitation polymerization is related to its activity and the temperature used for polymerization. Typical examples of inorganic persulfates include sodium, potassium, or ammonium persulfate, which exhibit useful activity in the temperature range of 65 °C to 105 °C. Radical polymerization initially requires sufficient radical production (radical flux) to allow polymerization to occur. The total amount of initiator, typically 0.2% to 5.0% by weight relative to the total weight of monomers used for polymerization, depends on the reaction temperature, the chain transfer agent, and the initiator efficiency. Increasing the initial charge to compensate for the slow polymerization kinetics is a method used in the present invention.In the present invention, a high quantity of the initiator, from 0.20 to 2.0%, preferably from 0.25 to 1.0%, is used. A mixture of one or more initiators as described above can be used to carry out the polymerization at a desired rate. Usually, a sufficient quantity of initiator is added initially to start the reaction, and then an additional initiator can optionally be added to maintain the polymerization at a convenient or desired rate. MONOMERS The invention relates to the preparation of a vinylidene fluoride polymer. The main monomer (meaning an amount greater than or equal to 97% by weight of the polymer) used in the present invention is vinylidene fluoride (“VDF”). Other non-fluorinated monomers with ethylenic unsaturation may be present (“non-fluorinated monomers”). A polymer is formed by the polymerization of vinylidene fluoride and optionally the non-fluorinated monomers, and it encompasses homopolymers, copolymers, terpolymers, and higher polymers, which are thermoplastic in nature, meaning that they can be transformed into useful parts by casting after the application of heat, as is done in molding and extrusion processes. The fluoropolymer contains at least 97 percent by weight of vinylidene fluoride, preferably at least 98 percent and more particularly at least 99 percent by weight, and is thermoplastic. Thermoplastic polymers have a crystalline melting point, as measured by differential analysis calorimetry (DAC). Non-fluorinated monomers can be added at the beginning of the polymerization reaction and / or during the polymerization reaction. The polymer of the invention may comprise non-fluorinated monomer units. Preferably, the polymer may optionally comprise non-fluorinated monomers having hydroxyl groups, carboxylic acid functional groups, or carboxyl functional groups; more particularly, the non-fluorinated monomers may comprise a carboxylic acid functional group. The non-fluorinated monomers that may be used in combination with VDF include, but are not limited to, one or more of the following non-fluorinated monomers of formula: Formula | To OR Formula IB RRR y 6 2 2 * R o 7 Oo t Ra Ra fi * Rs / I y Ra piO 4 N / X a KR | 4 Rs To in which R1, R2, and R3 each independently represent a hydrogen, a linear alkyl group, a branched alkyl group, or a cycloalkyl group having 1 to 8 carbon atoms; and in which R4 and R6 separately represent a bond, R4 and R6 independently represent a bond or an atomic group having a molecular mass of 500 or less and having a main chain having from 1 to 18 atoms; and in the case in which R4 or R6 represents a hydrogen, respectively RS or R7 does not exist; in which, when R4 and R6 do not represent a hydrogen, R5 and R7 separately represent a radical from among a carboxylic acid (C(O)OH), a carboxylate salt of an alkali metal (COO-M*), an ammonium carboxylate salt (COO-NH,*), an alkylammonium carboxylate salt (COO-N(AIk)4*), an alcohol (OH), an amide (C(O)NH;), a dialkylamide (C(O)NAIkz), a sulfonic acid (S(O)(O)OH), a sulfonate salt of an alkali metal (S(O)(O)OM*), an ammonium sulfonate salt (S(O)(O)O-NHZ-), an alkylammonium sulfonate salt (S(O)(O)ON(AIK),+), a ketone (C(O)) or an acetylacetonate (C(O)-CH2-C(O)) or a phosphonate (P(O)(OH)2), a phosphonate of an alkali metal or ammonium, preferably RS and R7 separately represent one of a carboxylic acid (C(O)OH), a carboxylate salt of an alkali metal (COO-M*), an ammonium carboxylate salt (COO-NH;*), an alkylammonium carboxylate salt (COO-N(AIK),*), an alcohol (OH), an amide (C(O)NH));Specifically, RS and R7 separately represent one of a carboxylic acid (C(O)OH), a carboxylate salt of an alkali metal (COO-M*), an ammonium carboxylate salt (COO-NH4+), an alcohol (OH). ; Examples of non-fluorinated monomers include acrylic acid, methacrylic acid, 2-carboxyethyl acrylate "CEA", acryloyloxypropyl succinate "APS", acryloyloxyethyl succinate "AES", hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate; hydroxyethylhexyl (meth)acrylates, acrylic acid esters such as alkyl (meth)acrylates, vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate; acrylamide, methacrylamide, 6-acrylamidohexanoic acid. Non-fluorinated monomers that may be used may include those set forth in WO2019199753, which is incorporated herein by reference. BUFFER AGENT The polymerization reaction mixture may optionally contain a buffering agent to maintain a regulated pH value throughout the polymerization reaction. The pH is preferably regulated in the range of approximately 2 to approximately 8 to minimize undesirable color development in the product. Buffering agents may include an organic or inorganic acid or a salt of an alkali metal thereof, or a base or a salt of such an organic or inorganic acid, having at least one pKa value in the range of about 4 to about 10, preferably from about 4.5 to about 9.5. Preferred buffering agents in the practice of the invention include, for example, phosphate buffers and acetate buffers. A "phosphate buffer" is a salt or salts of phosphoric acid such as dipotassium hydrogen phosphate. An "acetate buffer" is a salt of acetic acid such as sodium acetate. PVDF POLYMER CHARACTERISTICS The new polymerization process yields a new polymer composition. The composition comprises a PVDF polymer. The PVDF polymer of the invention is characterized in that it has a melting temperature between 165 °C and 175 °C, preferably from 168 °C to 174 °C, and has a raspberry-like morphology. The present invention relates to a polymer having mainly an f-phase crystallinity, as measured by the ratio of the intensities of the peaks of the fB-phase crystal: I pr200 / 110y / [La(020) + L020)] Greater than 5, preferably greater than 6 by use of a W'AXD as described in the examples. In one embodiment, the polymer has a melt viscosity of 53 to 150 kP at 100 s- and 900 to 3,500 kP at 4 s-. The viscosity in solution (cP) of the polymer of the invention as a 9% solution in NMP (measured at 3.36 / s) is at least 7,000 cP, preferably greater than 9,000 cP. PVDF polymer is thermoplastic and can be processed in the molten state. The PVDF polymer comprises at least 97% by weight of VDF, preferably at least 99%, and the PVDF polymer comprises up to 100% by weight of VDF. Preferably, the only fluorinated monomer present in the polymer is VDF (vinylidene fluoride). When using a non-fluorinated monomer, the amount of non-fluorinated monomer in the PVDF polymer is 0.001 to 3 percent by weight, preferably 0.01 to 1.5 percent by weight. It can be measured by ¹⁸F NMR and ¹H NMR. An unexpectedly high value of ΔH, AH in a DTA measurement, is greater than the AH obtained from a conventional a-phase PVDF, indicating that a B-phase structure has developed, rather than the conventional a-phase. Preferably, the AH (molten) (J / g) (first heating) is greater than or equal to 58. The primary particle size distribution of the PVDF polymer, obtained by the precipitation polymerization process, exhibits a wide range, as measured by the number-average particle size, from 100 nm to 800 nm, preferably from 100 nm to 700 nm, and preferably from 200 nm to 600 nm. In precipitation polymerization, the primary particles aggregate during the polymerization process until they grow sufficiently to precipitate as "precipitated particles." The average precipitated particle size is from 50 micrometers to 2,500 micrometers, preferably from 100 to 2,200 micrometers, and more particularly from 200 micrometers to 1,600 micrometers. No post-polymerization process is used to coagulate the polymer. Suspension polymerization differs from precipitation polymerization. Suspension polymerization is a technique suitable for preparing polymer particles. In suspension polymerization, a monomer phase is The mixture is suspended in the polymerization medium as small droplets using a stirrer and a suitable stabilizer. Both the initiator and the monomer are insoluble in the polymerization medium, while the initiator is soluble in the monomer, and polymerization takes place within the monomer droplets. Suspension polymerization yields spherical polymer particles with a size of 50 to 500 µm. In the present invention, the primary particle size ranges from 100 nm to 800 nm, while the precipitated particles range from 50 micrometers to 2,500 micrometers, preferably from 100 to 2,200 micrometers, and more particularly from 200 micrometers to 1,600 micrometers. The morphology of the precipitated particle has an irregular surface topography (“raspberry-like”), composed of agglomerated primary particles that also have an irregular shape, whereas the emulsion process yields a primary particle with a smooth surface, as can be seen by SEM. Figures 1 to 4 illustrate this difference in particle morphology between an emulsion polymerization process and a precipitation polymerization process. Figure 1 shows the average powder particle size obtained by atomizing a standard latex emulsion, which is on the order of 1 to 30 micrometers. In contrast, the average particle size obtained by precipitation polymerization in Figure 3 is on the order of 50 to 2200 micrometers. Figure 2 shows the powder particle obtained by conventional suspension polymerization. Figures 4 and 5 illustrate the difference in primary particle morphology.The primary latex particle obtained by a standard emulsion process gives round particles (as seen in [Fig.4]), with a narrow particle size distribution in the range of 100 to 500 nm. Precipitation polymerization gives precipitated particles consisting of a wide range of primary particle sizes, with a raspberry-like morphology, and which are interconnected and agglomerated (as seen in [Fig.5]). The polymer or copolymer of the invention can be isolated by standard techniques such as filtration or centrifugation, followed by oven drying for further application or use. Preferably, no fluorinated molecules are added to the polymerization process, other than the PVDF monomer and the resulting polymer. The polymer of the invention can be used for the manufacture of an anode, a cathode and / or separators for lithium-ion batteries. The polymer of the invention, used as a binder in a cathode, provides improved adhesion as measured according to ASTM D903, with a variant described below. Peel strength is 120% of that of the control (PVDF homopolymer by emulsion polymerization, with a melt viscosity of 50 kP). (100 s-!)), preferably 150% of that of the control, and more particularly 200% of that of the control. In some embodiments, the peel strength may be greater than 150 N / m, preferably greater than 160 N / m, preferably greater than 175 N / m. The typical formulation of a cathode is active ingredient / conductive material / binder. The active ingredient constitutes the largest part of the total, from 90 to 99.5% by weight, the binder charge is usually in the range of 0.5 to 5% by weight, and the conductive material / binder ratio is 4:1 to 1:4. An example of a formulation might be active ingredient / conductive material / binder in the proportion 97 / 1.5 / 1.5 by dry weight. Generally, the binder (polymer of the invention) is pre-dissolved in a solvent (such as, for example, NMP or another suitable solvent), usually at a concentration of 5 to 10% by weight. The conductive carbon additive is first mixed dry with the active material (lithium containing metal oxide compounds known for use in lithium-ion batteries). The binder solution is then mixed with the dry mixture of the conductive carbon material and the active material to form a thick, uniform paste. Alternatively, the conductive carbon can be mixed with the binder and the solvent, followed by the addition of the active material to form a paste. In either case, additional amounts of the solvent are added to the paste and mixed to gradually reduce the dry extract and viscosity of the suspension.This dilution step is repeated several times until the viscosity of the suspension reaches the value suitable for a coating, usually 3,000 to 15,000 cP for a shear rate of 1 / s. The cathode suspension is then poured onto a current collector by means known in the art to form a cathode. The usual surface mass for loading the cathode is 100 to 300 g / m², preferably 180 to 220 g / m². The anodes and separators can be produced in a similar manner by using the polymer of the invention as a binder, following processes known in the art, EXAMPLES Characterization methods / conditions: The molten viscosity measurements of the resin were carried out according to ASTM-D3835 by capillary rheometry at 232 °C and at 100 s- and 4 s-, Melting temperature, as measured by differential analysis calorimetry (DAT) on powder samples. Thermal characteristics, including melting point and ΔH, were measured according to ASTM D3418 using the TA Instruments DSC Q2000 with an LNCS. Polymers manufactured according to the The present invention contains a measurable level of crystalline poly(vinylidene fluoride), such as that indicated by the presence of a crystalline melting point in a temperature-dependent analysis (TDA). The melting temperature is assigned to the endothermic peak of the second cycle. The heat of fusion is determined in the first cycle. The TDA is implemented according to a three-stage cycle. The cycle begins at -20 °C, followed by a temperature ramp rate of 10 °C / min up to 210 °C, then a holding period of 10 minutes. The sample is then cooled at a rate of 10 °C / min down to -20 °C and then reheated at 10 °C / min up to 210 °C. The particle size distribution (number-average) measurements were obtained using scanning electron microscopy (SEM). SEM was performed on a Hitachi SU 8010 SEM. All polymer samples for SEM were dried at room temperature, with one coated sample applied before imaging. Experiments to determine the intensity ratio and wide-angle X-ray diffraction were performed on the Rigaku SmartLab diffraction platform (Cu Ka 1.5418 Å, 40 kV, 40 mA). Samples were placed on a low-bottom support for WAXS analysis in reflection mode. The diffractometer used for WAXS analysis was a Rigaku SmartLab equipped with a copper X-ray tube (Cu Ko 1.5418 Å) set at 40 kV and 40 mA, with a linear focus (the X-ray beam is used at the linear focus, which has dimensions of 12 mm in length and 1 mm in width). The experiments were conducted using a theta-theta (reflection) geometry with parallel-beam optics (a curved parabolic multilayer mirror, transforming a naturally divergent X-ray beam into a parallel X-ray beam with very low divergence). 1D reflection mode.The incident slit (IS) is set to a 1 mm aperture, the length-limiting slit has a 10 mm aperture, and the two receiving slits RS1 and RS2 have a 3 mm aperture. The detector is a Rigaku Hypix 3000 used in 1D mode. Data are collected over a 26° arc from 5.0° to 80.0° in continuous mode, with a step size of 0.02°, and a sweep speed of 0.5° / min. The ratio of the B-PVDF to the a-PVDF and / or y-PVDF was calculated by dividing the intensities. The sum of the B-PVDF (200) and the B-PVDF (110) is divided by the sum of the a-PVDF (020) and the y-PVDF (020). Iaç2o0 / 110) / [ato20y + L4020)] = ratio of intensities. . The viscosity in solution was measured at 25 °C using a Brookfield viscometer, specifically a Brookfield DVII viscometer, SC4-25 spindle, at 3.36 s. Sample preparation for viscosity measurement: PVDF resin was dissolved in 9% wt% 1-methyl-2-pyrrolidinone. The resin / solvent mixture was blended on a roller mixer for at least 72 hours at room temperature to ensure complete dissolution. Examples 1-3 The experiments were carried out in a 1.7 L stainless steel reactor into which 1000 g of water was introduced. The reactor was purged with nitrogen gas. The reactor was hermetically sealed, and stirring was initiated at 72 rpm. Stirring was maintained throughout the entire reaction. The reactor was heated to the desired temperature, as shown in Table 1. The reactor was loaded with vinylidene fluoride to the desired pressure of approximately 4481 kPa (650 psi). After pressurization, the reactor was loaded with the initiator solution. The initiator solution was an aqueous solution of potassium persulfate initiator 1% (from EMD Chemicals, grade ACS). A continuous feed of the aqueous initiator solution was added to the reaction to achieve a suitable polymerization rate.The reaction temperature was maintained at the desired temperature, and the reaction pressure was maintained at 4481 kPa (650 psi) by adding vinylidene fluoride as needed. The VDF supply was stopped when the desired amount of VDF consumed was reached. Stirring was continued and the temperature maintained for 30 minutes. Then, stirring and heating were stopped. After cooling to room temperature, the excess gas was vented to the atmosphere. All solids produced by the reaction were collected in a suitable receiving container. The solids exiting the reactor were dried by a convection oven. Comparative example 1 is the same as Example 1, except that the temperature was 73 °C. Comparative examples 2 and 3 are commercial-grade PVDF homopolymers, manufactured by conventional emulsion polymerization. [Tables l1lA] Homopolymer [Example number fo qic6 [54 |Example number |Temperature (CC) (2nd AH (in the molten state, |heating) |molten) (J / g) reaction (° |molten kP |kP at 100 s ! (1st C) at 4s1 heating) Example 1 63 2 600 103 171 65 Example 2 68 100 168 60 Example 3 58 123 170 66 comparative [73 |758 70 |163 48 1 comparative [more than 75 [00 |50 [163 Jes 2 por comparative [more than | Je 166 4 3 [Table 1B] Homopolymer [Example number Granulometrite | Granulometrite | Primary viscosity | Aggregate viscosity | In solution (am) (um) (cP) 300-500 | 370-1300 | >20,000 200-600 >20,000 400-600 | 500-1400 | 220-280 Temperature [Reaction ratio | of intensities (eC) Q) 63 22 68 7 58 87 (73 0 [more than 75 0.5 200-220 [more than 75 | O 200-220 1 The ratio of peak intensities was calculated using the sum of B(200) and B(110) observed around 26°C at 20.6°C with CuKa radiation, compared to the peak intensity of B(020) around 20°C at 18.3°C with radiation. Cu Ka or the intensity of the peaks of y (020) observed around 26 18.3 ° with the Cu Ka radiation, or the sum of the intensities of the peaks of a (020) and y (020) if both polymorphs are present. Examples 4-6 The experimental technique is very similar to that described in Examples 1-4. 1000 g of water was introduced into a 1.7 L stainless steel reactor. The reactor was purged with nitrogen gas. It was hermetically sealed, stirred at 72 rpm, and heated to 63 °C. The reactor was charged with vinylidene fluoride to reach the desired pressure of 4481 kPa (650 psi). After pressurization, the reactor was charged with an initiator solution. The initiator solution was a 1% aqueous solution of potassium persulfate initiator (from EMD Chemicals, ACS grade). A continuous feed of the aqueous initiator solution was added to the reaction to achieve the appropriate polymerization rate. Co-monomers prepared as a 1% solution were added during the reaction.The reaction temperature was maintained at 63 °C and the reaction pressure at 4481 kPa (650 psi) by adding vinylidene fluoride and, if necessary, a non-fluorinated monomer. When the desired amount of VDF consumed was reached, the monomer supply was stopped. Stirring was continued and the temperature maintained for 30 minutes. Then, both stirring and heating were stopped. After cooling to room temperature, the excess gas was vented to the atmosphere, and the polymer material produced by the reaction was collected in a suitable receiving container. [Tables 2] |4 208 |CEA [L62 |s8 |1 803 |88 [169 |15 [22 400 Copolymers with a non-fluorinated monomer Exem |Charg|Charge |Utilisatio Duration |Viscosit |Viscosity |Tm [Viscosity Ratio | ple e of in of KPS |of the e to the state |(C) |of the in- |éen numér [total [|monom |(g) reaction the state |molten, tensions solution | o of ère non-| (min) molten, |kPà VDF |F(g) KP at 4 s-1100 s°! (g) ! |} [208 jcœa ju62 |s8 [1803 |ss |ieo|i5 [2240 | 0.4g |s 177 |CEA |1.91 73 2020 |86 169 |15 15200 0.6g [6 [1 jas [20 ji&2 [1410 j8 |i69[17 |14200 0.5g CEA represents 2-carboxyethyl acrylate AA represents acrylic acid. The PVDF polymer of the invention can be used to manufacture battery electrodes or battery separators. The dried polymer is used to prepare a cathode suspension. Formulation and manufacturing of a cathode Two examples of laboratory-scale cathodic suspension preparation techniques are described here. Method 1: First, carbon black is mixed with the binder solution, then the active material is added. Method 2: Carbon black and the active material in dry powder form are mixed with the binder solution. Both methods are used in the lithium-ion battery industry. The following techniques are intended for laboratory-scale preparation, with a target formulation of NMC622 (lithium active material) / SuperP (carbon black) / binder = 97 / 1.5 / 1.5, on a dry basis. Suspension Preparation Method No. 1: 0.36 g of a conductive carbon additive, Timcal's SuperP-Li, is added to 4.50 g of the 8.0% binder solution. The mixture is then blended using a Thinky AR-310 centrifugal planetary mixer for three 120-second cycles at 2000 rpm, with 1 minute of air cooling between each cycle. Once the conductive carbon is dispersed in the binder solution, 23.28 g of an active ingredient, Celcore® NMC622 (Umicore), and a small amount of NMP (0.5 g) are added to the mixture. The mixture is then blended to form a thick, uniform paste, usually for 60 seconds at 2000 rpm. A small amount of NMP (0.5 g) is added and mixed for 60 s at 2000 rpm to gradually reduce the dry extract and viscosity of the suspension. This dilution step is repeated several times until the suspension viscosity reaches the value suitable for coating, usually 3000 to 15,000 cP at a shear rate of 1 / s. Typically, the final dry extract for the NMC622 / SuperP / binder = 97 / 1.5 / 1.5 formulation is approximately 80% by weight. Suspension Preparation Process No. 2: First, 0.36 g of a conductive carbon additive, such as Timcal's SuperP-Li, is mixed with 23.28 g of an active ingredient, such as Celcore® NMC622 (Umicore), using a Thinky AR-310 centrifugal planetary mixer, twice for 60 seconds at 1500 rpm. Then, 4.50 g of an 8% binder solution is added, and the mixture is blended to form a thick, uniform paste, usually for 60 seconds at 2000 rpm. Finally, a small amount of NMP (0.5 g) is added to the paste, and the mixture is blended for 60 seconds at 2000 rpm to gradually reduce the dry extract and viscosity of the suspension. This dilution step is repeated several times until the viscosity of the suspension reaches the level suitable for a coating, usually 3,000 to 15,000 cP for a shear rate of 1 / s. Electrode casting and drying: The cathode suspension is then cast onto an aluminum foil (current collector, 15 µm thick) using an adjustable squeegee on an automatic film applicator (Elcometer 4340) at an application speed of 0.3 m / minute. The squeegee gap is adjusted empirically to give a dry thickness of approximately 80 micrometers, or a surface density of approximately 200 g / m². The wet cast product is then transferred to a convection oven and dried at 120 °C for 30 min. After drying, the electrode is calendered using a rolling mill (Hohsen HSTK-1515H), and the final density of the NMC622-based electrode is typically around 3.4 g / cm³. Peel strength data are obtained by the peel test method as described below. For the peel test, cathode samples fabricated using the polymer of the invention are cut into 1" wide strips, 5" to 8" long. The samples are dried in a vacuum oven at 85°C overnight and then stored in a dry location. The cathode peel strengths are obtained by a 180° peel test according to ASTM D903, with several modifications. The first modification was that the extension rate was set at 50 mm / minute (peel rate 25 mm / minute). The second modification was that the test samples were dried (as described above) before the peel test, and the peel test was performed in a dry location, as variations in exposure to ambient humidity can significantly affect the peel test results.The 1" wide test strip is glued to the alignment plate. Using 3M 410M double-sided paper tape, the current collector, consisting of a flexible aluminum foil, was peeled by the grips of the testing machine. The mechanical dynamometer was an Instron model 3343 with a 10 N load cell. The peel test results are reported in N / m. [Tables 3] [Peel test results] |Binder |PVDF-CE PVDF-AA |PVDF F-CE | PVDF-AA |Ex. No. Read |6 PVDF-CE A | : Comparative example 2121 Pelage, N / m |179 190 Comparative example 2 is a PVDF homopolymer, melt viscosity 50 kP at 100 s!, available from Arkema Inc. The new polymers containing VDF show very good results in the peel test, as shown.

Claims

Demands

1. Polymer poly(vinylidene fluoride) characterized in that said The polymer has a melting point between 165°C and 175°C. preferably between 168°C and 174°C, exhibits a morphology in raspberry and a ratio of phase intensities (3 (T / (200 / 110) / [Lao20) + 1 020)] ) greater than 5.

2. Poly(vinylidene fluoride) polymer according to claim 1, the polymer having a melt viscosity of 53 to 150 KP at 100 s*! and from 900 to 3,500 KP at 4 s-!,

3. Poly(vinylidene fluoride) polymer according to claim 1, the viscosity in a 9% by weight solution in NMP (measured at 3.36 / s) being at least 7,000 cP, preferably greater than 9,000 cP.

4. Poly(vinylidene fluoride) polymer according to claim 1, the delta H (first heating) being greater than 58 J / g.

5. Poly(vinylidene fluoride) polymer according to claim 1, the polymer comprising at least 97% by weight of monomer units vinylidene fluoride.

6. Poly(vinylidene fluoride) polymer according to any one of the re- claims 1 to 5, the polymer being a homopolymer.

7. Poly(vinylidene fluoride) polymer according to any one of the re- claims 1 to 5, the polymer comprising at least one non-monomer fluorinated.

8. Poly(vinylidene fluoride) polymer according to claim 7, in of which at least one non-fluorinated monomer comprises at least one of acrylic acid (AA), carboxyethyl acrylate (CEA) and the acryloyloxyethyl succinate (AES).

9. Poly(vinylidene fluoride) polymer according to claim 7, the polymer in the form of precipitated particles having a average precipitate particle size having a size in the range of 50 micrometers to 2,500 micrometers, preferably from 100 to 2200 micrometers.

10. | Poly(vinylidene fluoride) polymer according to claim 9, the ratio of intensities being greater than 6.

11. | Precipitation polymerization process for producing the polymer poly(vinylidene fluoride) according to any one of claims 1 to 10 having a phase |, the process comprising the steps of introducing water in a reactor, to purge said reactor with a gas to eliminate oxygen, to heat said reactor, to introduce into said reactor vinylidene fluoridene and a possible non-fluorinated monomer for to reach the desired pressure, to introduce a priming solution in said reactor, possibly to continuously supply the solution of initiator during polymerization, the reaction temperature polymerization temperature being kept constant between 50 °C and 70 °C during the reaction, and the pressure being maintained between 280 and 40,000 kPa, to supply a monomer to maintain the pressure and to continue the polymerization reaction until the amount of When the consumed VDF reaches the predefined value, release it into the atmosphere. excess gas, to recover the precipitated polymer by collecting the solid materials that precipitated during the polymer- reaction risation, the amount of initiator used for polymerization being of at least 2,000 ppm.

12. A method according to claim 11, wherein the initiator solution aqueous contains an inorganic persulfate.

13. The method according to claim 11, wherein the initiator comprises at minus one of the following: hydrogen peroxide, sodium persulfate, the potassium persulfate or ammonium persulfate.

14. Method according to claim 11, wherein the temperature range is from 53°C to 69°C, preferably from 58°C to 68°C.

15. A method according to any one of claims 11 to 14, wherein The quantity of priming agent is 2,000 ppm to 10,000 ppm, preferably from 3,000 to 8,000 ppm, relative to the total monomer weight.

16. | A method according to any one of claims 11 to 14, wherein No surfactant is added to the reactor.

17. A method according to any one of claims 11 to 14, wherein the non-fluorinated monomer is fed at the beginning of the reaction and / or during the reaction.

18. A method according to any one of claims 11 to 14, in which The amount of non-fluorinated monomer added is 0.05 to 5 percent in weight, preferably 0.1 to 3 percent by weight relative to the total monomer used.

19. A method according to any one of claims 11 to 14, wherein the non-fluorinated monomer comprises at least one non-fluorinated monomer chosen from the group consisting of acrylic acid (AA), acrylate of carboxyethyl (CEA) and acryloyloxyethyl succinate (AES).

20. | Suspension composition for the production of an ion- battery lithium, comprising the polymer poly(vinylidene fluoride) according to the Claim 1, an active electrode material, a non-aqueous solvent and, possibly, an additive conferring electrical conductivity and / or a viscosity-modifying agent.

21. A suspension composition according to claim 20, comprising: (a) the polymer poly(vinylidene fluoride), in an amount of 0.5 to 5% by weight, preferably 0.5 to 3% by weight, relative to the total weight of (a) + (b) + (c); (b) an additive conferring electrical conductivity, in an amount of 0.5 to 5% by weight, preferably 0.5 to 3% by weight, relative to the total weight of (a) + (b) + (c); (c) an active substance of electrode in a quantity of 90 to 99% by weight, preferably 95 to 99% by weight.

22. | Electrode for lithium-ion battery obtained by application of the com- suspended position according to claim 21 to a collector, and coating drying.

23. Lithium-ion battery comprising the electrode according to claim 22.

24. Article comprising the poly(vinylidene fluoride) polymer according to the re- demand |

25. A method for producing a battery electrode comprising the steps consisting of: L supply the poly(vinylidene fluoride) polymer according to the re- claim 1, the polymer poly(vinylidene fluoride) se presenting in the form of precipitated particles having a gra- average nulometry from 50 micrometers to 2,500 micrometers, ii. combine the poly(vinylidene fluoride) polymer from i), with a solvent and an electrode material to provide a com- position forming an electrode, the polymer poly(fluoride of vinylidene) being dissolved in the solvent, lil. apply the electrode-forming composition to at least a surface of an electrically conductive substrate, and evaporate the solvent in the composition forming an electrode to form a composite electrode layer on the electro- substrate driver.