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    • 专利摘要:
    The present invention relates to a method for preparing a crosslinked fluoropolymer film, comprising the successive steps of: (1) formulating an ink containing, preferably consisting of: (a) at least one fluorinated copolymer obtained by radical copolymerization monomers comprising, and preferably consisting of: (i) vinylidene fluoride (VDF), (ii) trifluoroethylene (TrFE), (iii) at least one chlorinated monomer of formula - CXC1 = CX1X2 where X, X1 and X2 independently denote H, F or CF3, it being understood that at most one of X, X1 and X2 denotes CF3; (b) triethylamine; (c) at least one crosslinking agent; (d) at least one photoinitiator; and (e) at least one organic solvent; (2) applying said film ink to a substrate; and (3) UV irradiating said film. It also relates to the film obtainable by this method, as well as its uses, in particular in the manufacture of electronic (opto) devices and more particularly in the manufacture of a gate dielectric layer in a field effect transistor.
    公开号:FR3069544A1
    申请号:FR1757202
    申请日:2017-07-28
    公开日:2019-02-01
    发明作者:Thierry Lannuzel；Fabrice Domingues Dos Santos；Thibaut SOULESTIN；Vincent Ladmiral；Bruno Ameduri
    申请人:Centre National de la Recherche Scientifique CNRS；Universite de Montpellier I；Arkema France SA；Ecole Nationale Superieure de Chimie de Montpellier ENSCM；Universite de Montpellier；
    IPC主号:
    专利说明:


    PROCESS FOR THE PREPARATION OF A CROSSLINKED FLUORINATED POLYMER FILM
    FIELD OF THE INVENTION
    The present invention relates to a process for preparing a crosslinked fluoropolymer film. It also relates to the film capable of being obtained according to this process, as well as its uses, in particular in the manufacture of (opto) electronic devices and more particularly as a gate dielectric layer in a field effect transistor.
    TECHNICAL BACKGROUND
    Vinylidene fluoride (VDF) fluorinated polymers represent a class of compounds with remarkable properties for a large number of applications. PVDF and the copolymers comprising VDF and trifluoroethylene (TrFE) are particularly interesting because of their ferro-, piezo- and pyroelectric properties. These materials, electroactive fluorinated polymers, or PFEAs, have a spontaneous polarization at low temperature, which can be reversed by application of an external electric field. The variation of their polarization as a function of the field is not linear and, if the electric field is alternating, the polarization describes a hysteresis cycle characterized by the remanent polarization and the coercive field (applied electric field necessary for the cancellation of polarization). Beyond a transition temperature, ferroelectric materials exhibit behavior close to that of a linear dielectric material, separating the ferroelectric state from a paraelectric state.
    Among the ferroelectric materials, it is possible to distinguish, according to the characteristics of their transition but also by their frequency behavior, the conventional ferroelectric materials and the relaxant ferroelectric materials. Precisely, conventional ferroelectric materials exhibit a narrow maximum of their dielectric constant at the Curie temperature Te where the ferroelectric - paraelectric transition occurs. The value of Te is also independent of the frequency. On the contrary, the relaxant ferroelectric materials have a dielectric permittivity curve (also called dielectric constant) as a function of the temperature comprising a diffuse transition peak extending over a relatively wide temperature range, Tc where the ferroelectric relaxant transition occurs - paraelectric. In addition, the maximum dielectric constant is shifted to higher temperatures when the frequency increases.
    It is known that the use of a third monomer carrying a bulky substituent, such as chlorofluoroethylene (CFE) or chlorotrifluoroethylene (CTFE) makes it possible to modify the crystallization of ferroelectric polymers based on VDF and TrFE, so as to their confer properties of relaxants with significant electrostrictive effects and better dielectric permittivity.
    However, these ferroelectric polymers and ferroelectric relaxers must be crosslinked to improve their electronic and mechanical properties, in particular their dielectric constant, with a view to their incorporation in certain devices such as transistors. Crosslinking also gives these polymers resistance to solvents, enabling them to be used in photolithography processes. It is in particular desirable that they can be photo-crosslinked, in particular to allow the production of patterns (“patterning”) from a layer or film of the polymer, and in order to avoid the problems inherent in films obtained by crosslinking. thermal.
    It has already been suggested in application WO 2015/200872 a process for the photocrosslinking of fluorinated polymers, such as a terpolymer (VDF-ter-TrFE-ter-CFE), comprising the formulation of an ink containing this copolymer, a base non-nucleophilic, such as a tertiary amine of polycyclic or heteroaromatic structure, and a crosslinking agent. This ink is deposited on a substrate to form a film which is then exposed to UV, so that the base causes dehydrohalogenation of the copolymer. A double bond is thus formed in the structure of the copolymer, and hydrochloric acid is released. This double bond can then be crosslinked by the crosslinking agent. In this process, the steric hindrance generated by the amine makes it possible to avoid the reaction of the amine with the fluorine atoms present in the copolymer and thus lead to the concomitant formation of hydrogen fluoride.
    It appeared to the Applicant that a particular base, having a small steric hindrance, namely triethylamine, could be substituted for the tertiary amines of WO 2015/200872 without appreciably affecting the electronic, thermal and / or chemical properties of the crosslinked film obtained , or even improving at least some of these properties.
    Triethylamine has already been used in dehydrochlorination reactions of co- or terpolymers of the poly type (VDF-ier-TrFE-ier-CTFE) (J. Mater. Chem., 2013, 1, 10353-10361) and of the poly type (VDF-co-CTFE) (J. Mater. Chem., 2012, 22, 1849618504). The copolymers described in the second publication do not, however, exhibit ferroelectric relaxant properties due to the absence of trifluoroethylene monomer. In addition, in these two publications, the resulting materials are crosslinked using thermal peroxides. These peroxides, often used at high temperatures (above 100 ° C) do not allow the production of patterns at room temperature. These methods are therefore not suitable for the manufacture of electronic devices.
    SUMMARY OF THE INVENTION
    The subject of the invention is a process for the preparation of films of crosslinked fluoropolymers, comprising the successive stages of:
    (1) formulation of an ink containing, preferably consisting of: (a) at least one fluorinated copolymer obtained by radical copolymerization of monomers comprising, and preferably consisting of: (i) vinylidene fluoride (VDF), (ii ) trifluoroethylene (TrFE), (iii) at least one chlorinated monomer of formula CXCl = CXiX2 where X, Xi and X2 independently denote H, F or CF3, it being understood that at most one of X, Xi and X2 denotes CF3 ; (b) triethylamine; (c) at least one crosslinking agent; (d) at least one photo-initiator; and (e) at least one organic solvent;
    (2) applying said ink as a film to a substrate; and (3) UV irradiation of said film.
    The subject of the invention is also a crosslinked fluoropolymer film capable of being obtained according to this process, as well as the use of this film for the manufacture of (opto) electronic devices, including thin film transistors, light transistors, field effect transistors and capacitors; haptic devices; actuators; electromechanical microsystems (MEMS); sensors; orientable catheters; Braille keyboards; acoustic devices (speakers or “tweeters”); electrocaloric devices; energy recovery devices, preferably in the manufacture of transistors.
    It has been observed that the method according to the invention makes it possible to obtain an electroactive semi-crystalline material having a high resistance to solvents, a low coercive field, a high electrical permittivity and / or a polarization at high saturation.
    DESCRIPTION OF EMBODIMENTS OF THE INVENTION
    As indicated above, the present invention relates to a process for the preparation of a film from an ink containing an electroactive fluorinated copolymer.
    The fluorinated copolymer used in this invention comprises a unit derived from vinylidene fluoride (VDF) and a unit derived from trifluoroethylene (TrFE). It also contains at least one chlorinated monomer of formula-CXCl = CXiX2 where X, Xi and X2 independently denote H, F or CF3, it being understood that at most one of X, Xi andX2 denotes CF3. Examples of such chlorinated monomers are in particular chlorofluoroethylene (CFE), chlorotrifluoroethylene (CTFE), 2-chloro-3,3,3-trifluoropropene, 1chloro-3,3,3-trifluoropropene, preferably CTFE and CFE. This copolymer can also contain at least one other unit derived from a fluorinated monomer, which can in particular be chosen from: tetrafluoroethylene (TFE), Thexafluoropropylene (HFP), 2- (trifluoromethyl) acrylic acid, trifluoropropene, tetrafluoropropene , hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropene, perfluoroalkyl ethers such as PMVE, PEVE and PPVE, and mixtures thereof. It is understood that all the geometric isomers of the above-mentioned fluorinated compounds are included in the above terminologies, such as 3,3,3trifluoropropene, 2,3,3,3-tetrafluoropropene (or 1234yf), 3-chloro -2,3,3trifluoropropene (or 1233yf). In addition, it is preferred that the copolymer according to the invention does not contain a motif derived from a non-fluorinated monomer). According to one embodiment of the invention, the fluorinated copolymer is a terpolymer containing only units derived from VDF, TrFE and the chlorinated monomer.
    According to one embodiment, the proportion of units from TrFE is preferably 5 to 95 mol.% Relative to the sum of units from VDF and TrFE, and in particular: from 5 to 10 mol.%; or from 10 to 15 mol.%; or from 15 to 20 mol.%; or from 20 to 25 mol.%; or from 25 to 30 mol.%; or from 30 to 35 mol.%; or from 35 to 40 mol.%; or from 40 to 45 mol.%; or from 45 to 50 mol.%; or from 50 to 55 mol.%; or from 55 to 60 mol.%; or from 60 to 65 mol.%; or from 65 to 70 mol.%; or from 70 to 75 mol.%; or from 75 to 80 mol.%; or from 80 to 85 mol.%; or from 85 to 90 mol.%; or from 90 to 95 mol.%. A range of 15 to 55 mol.% Is particularly preferred.
    The proportion of units derived from the chlorinated monomer (relative to all of the units) can vary for example from 1 to 20 mol.%, In particular from 5 to 15 mol.%.
    For their part, the units originating from the additional monomer which may be present may represent from 0 to 20 mol.% And preferably from 5 to 15 mol.%, Relative to all of the units.
    The copolymers used according to the invention are advantageously statistical and linear.
    The copolymers used according to the invention are prepared by radical polymerization according to a solution, suspension, emulsion or micro-emulsion polymerization process.
    The copolymerization reaction is generally carried out in the presence of a radical initiator. This can for example be a t-alkyl peroxyester such as ieri-butyl peroxypivalate (or TBPPI), ieri-amyl peroxypivalate, a peroxydicarbonate such as bis (4-ier / -butyl cyclohexyl) peroxydicarbonate, sodium, ammonium or potassium persulfate, benzoyl peroxide and its derivatives, a / < / 7-alkyl hydroperoxide such as ieri-butyl hydroxyperoxide, a talkyl peroxide such as ieri-butyl peroxide or a t-alkyl-peroxyalkane such as
    2,5-bis (ieri-butylperoxy) -2,5-dimethylhexane. As a variant or in addition, an azo initiator or a redox system can be used as radical initiator.
    According to a first embodiment, the copolymer used according to the invention is prepared by a radical polymerization process in solution, such as that described in particular in patent application WO 2014/162080, comprising a step of copolymerization of a reaction mixture fluorinated monomers and chlorinated monomer in the presence of a radical initiator in a solvent.
    According to a particular embodiment:
    the proportion of TrFE in the reaction mixture is preferably from 5 to 95 mol.% relative to the sum of the VDF and TrFE monomers, and in particular: from 5 to 10 mol.%; or from 10 to 15 mol.%; or from 15 to 20 mol.%; or from 20 to 25 mol.%; or from 25 to 30 mol.%; or from 30 to 35 mol.%; or from 35 to 40 mol.%; or from 40 to 45 mol.%; or from 45 to 50 mol.%; or from 50 to 55 mol.%; or from 55 to 60 mol.%; or from 60 to 65 mol.%; or from 65 to 70 mol.%; or from 70 to 75 mol.%; or from 75 to 80 mol.%; or from 80 to 85 mol.%; or from 85 to 90 mol.%; or from 90 to 95 mol.%, a range of 15 to 55 mol.% being particularly preferred;
    - The proportion of chlorinated monomer in the reaction mixture can vary for example from 1 to 20 mol.%, in particular from 5 to 15 mol.%; and
    the proportion of additional monomer possibly present in the reaction mixture can represent from 0 to 20 mol.% and preferably from 5 to 15 mol.%, the above percentages being expressed relative to all of the monomers present in the mixture reaction, the sum of which is equal to 100%.
    According to one embodiment, the reaction mixture essentially consists of, and preferably consists of, a mixture of vinylidene fluoride, trifluoroethylene, chlorinated monomer, radical initiator, and solvent. By “consists essentially”, it is meant that it contains at least 70 mol%, more preferably at least 80 mol%, for example at least 90 mol%, or even at least 95 mol%, of these constituents.
    The reaction is carried out in a solvent, which is for example chosen from an organic solvent such as 1,1,1,3,3-pentafluorobutane, 2,2,2-trifluoroethanol, hexafluoroisopropanol; 1,1,2-trifluorotrichloroethane; dimethylformamide; dimethylacetamide; dimethyl sulfoxide; ketones, including acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclopentanone; furans, especially tetrahydrofuran; esters, including methyl acetate, ethyl acetate, propyl acetate, butyl acetate and propylene acetate glycol methyl ether; carbonates, in particular dimethylcarbonate; phosphates, especially triethylphosphate; water and mixtures thereof.
    According to one embodiment, the reaction mixture is heated to a reaction starting temperature of between 20 and 100 ° C and preferably between 25 and 80 ° C. The initial pressure inside the autoclave varies depending on the solvent, the reaction temperature and the amount of monomers. It is generally between 0 to 80 bars, for example between 20 and 40 bars. The choice of the optimal temperature depends on the initiator that is used. Generally, the reaction is carried out for a period of two to four times the half-life time of the initiator used, for example from 6 hours to 25 h, at a temperature at which the half-life time of 1 'initiator is between 1 and 10 hours.
    The molar mass of the copolymer obtained by solution polymerization is preferably from 5,000 to 200,000 g / mol, more preferably from 10,000 to 150,000 g / mol.
    According to another embodiment, the copolymer used according to the invention is prepared by a radical suspension polymerization process, such as that described in particular in patent application WO 2010/116105, comprising a step of copolymerization of a reaction mixture monomers in the presence of water, a radical initiator, optionally a dispersing agent and, optionally, a chain transfer agent.
    The suspension process avoids the use of toxic solvents and fluorinated surfactants (PEOA or bioaccumulative, toxic and persistent PEOS type) during the synthesis and purification of the copolymer.
    In the suspension process, the monomers are loaded into a stirred reactor containing deionized water, optionally a dispersing agent and, optionally, a chain transfer agent.
    The reactor is then brought to the desired initiation temperature, this temperature being maintained during the polymerization at a value between 40 and 60 ° C. The initiator is then injected into the reactor to start the polymerization. The consumption of the monomers leads to a pressure reduction which is generally maintained in the range of 80 to 110 bars by injection of deionized water or a mixture of monomers. The reactor is then cooled and degassed. The product is unloaded and recovered in the form of a suspension. This suspension is filtered and the wet powder is washed and then dried.
    According to yet another embodiment, the copolymer used according to the invention is prepared according to a radical emulsion polymerization process.
    To do this, an aqueous dispersion of the initiator stabilized by the surfactant used to conduct the polymerization is advantageously prepared. It is preferred not to use a perfluorinated surfactant. To achieve this dispersion, water, the initiator and a small fraction of all of the surfactant are mixed in a disperser. It is this dispersion which is added at the start and then possibly during the polymerization. After loading the polymerization reactor with water, surfactant and optionally paraffin, the reactor is pressurized, after removing the oxygen, by adding vinylidene fluoride alone or as a mixture with the comonomers and the result is the chosen temperature. Advantageously, the aqueous emulsion is polymerized at a temperature of 50 to 130 ° C. Preferably, the polymerization is carried out at an absolute pressure of 40 to 120 bars. The start of the reaction is obtained by adding the initiator dispersion. During the polymerization, the VDF is optionally added alone or as a mixture with the comonomers to maintain the pressure or to obtain a controlled pressure variation. Optionally, the initiator is added in increments or continuously. A chain transfer agent (CTA) can optionally be added at the start or during the polymerization. In the latter case, it can be introduced in increments or continuously. After introduction of the expected quantity of monomer mixture, the reactor is degassed and cooled and the latex is drained.
    The recovery of the polymer from the latex constitutes the finishing operation. This essentially consists in coagulating the latex and then drying the coagulate to obtain a dry powder. Finishing can also include a washing step. This washing can, for example, be carried out by introducing the latex, optionally diluted, into a coagulator where it is subjected to shearing in the presence of air. Under the combined effect of these two actions, the latex turns into an aerated cream with a density lower than that of water. This cream is optionally washed against the current with deionized water, for example according to the method described in US patents 4,128,517 and EP 0 460 284. The drying can be carried out by any industrial means known to those skilled in the art. art. In particular, the coagulated latex or the cream can advantageously be dried in an atomizer. Thus, at the outlet of the washing column or immediately after coagulation, the aerated cream is sent to a storage container before being directed by pumping into an atomizer which transforms it into a dry powder. This drying step in an atomizer can also be applied to the initial latex, optionally diluted, to coagulated latex (for example by mechanical shearing with or without prior dilution) or also to aerated cream.
    Another emulsion polymerization process which can be used to prepare the copolymer used according to the invention is that described in document US Pat. No. 7,122,608.
    The copolymer according to the invention is formulated in a photo-crosslinkable ink comprising triethylamine, at least one crosslinking agent, at least one photoinitiator and at least one organic solvent.
    As indicated previously, triethylamine makes it possible to dehydrochlorinate the copolymer, that is to say to eliminate a molecule of HCl from each CFCI-CH2 unit with which it is capable of reacting. These units can come, for example, from a CFE monomer or from a VDF-CTFE dimer. Double bonds are thus created in the copolymer, which can then react with the crosslinking agent to crosslink it. Advantageously, the method according to the invention does not generate substantially hydrofluoric acid (HF).
    The proportion of triethylamine is preferably adjusted so as to retain -CFCI-CH2- units within the copolymer at the end of the process.
    Triethylamine can thus represent from 0.1 to 2 molar equivalents relative to the number of moles of chlorinated monomer, preferably from 0.2 to 1.5 molar equivalents.
    The crosslinking agent can be any compound capable of reacting with double bonds, in particular a small molecule or a polymer or prepolymer carrying either one or more thiol groups capable of reacting with the double bonds by click-thiol-ene chemistry, either of one or more amine groups capable of reacting with the double bonds by hydroamination, or of one or more maleimide groups capable of reacting with the double bonds by conjugation. Alternatively, the crosslinking agent can be a small molecule or a polymer or prepolymer carrying one or more vinyl groups. It is understood that the examples above are not limiting and that it is also possible to use a crosslinking agent carrying more than one of the above reactive groups or several crosslinking agents carrying different reactive groups. Examples of such crosslinking agents include in particular poly (3mercaptopropylmethylsiloxane, maleimide siloxane, pentaerythritol tetrakis (3mercaptopropionate), trimethylethylenediamine, 1,2-diamino-4,5difluorobenzene and butane-1,4-trans-cinnamate, that this list is not exhaustive.
    The preferred crosslinking agents for use in the present invention are monomers or oligomers carrying at least two reactive (meth) acrylic functions in radical polymerization, which can optionally also comprise at least one other function chosen from hydroxyl, ester and ether functions , urethanes, epoxy, cyanurates or iso-cyanurates. Mention may thus be made, for example, of the following compounds: 1,3-butylene glycol di (meth) acrylate, butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, hexanediol alkoxylated di (meth) acrylate, neopentyl glycol alkoxylated di (meth) acrylate, dodecyl di (meth) acrylate, cyclohexane dimethanol di (meth) acrylate, diethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, linear alkanes di (meth) acrylate, bisphenol A ethoxylated di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tricyclodecane dimethanol diacrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol ethoxylated tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, penta (meth) acrylate ester, pentaerythritol tetra (meth) acrylate, trimethylolpropane ethoxylate tri (meth) lkoxylated tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane propoxylated tri (meth) acrylate, trimethylolpropane trimethacrylate, dodecanediol di (meth) acrylate, dodecane di (meth) acrylate, dipentaeryt (meth) acrylate, pentaerythritol tetra (meth) acrylate, di-trimethylolpropane tetra (meth) acrylate, glyceryl propoxylated tri (meth) acrylate, glyceryl propoxylated tri (meth) acrylate, tris (2-hydroxy ethyl) isocyanurate tri (meth) acrylate , polyesters (meth) acrylates, polyethers (meth) acrylates, polyethylene glycol (meth) acrylates, polypropylene glycol (meth) acrylates, polyurethanes (meth) acrylates, epoxy (meth) acrylates, and combinations thereof. The crosslinking agent can represent from 1 to 20% and preferably from 3 to 10% by moles, relative to the number of moles of copolymer.
    Examples of photoinitiators which can be used in the ink used according to the invention include: 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2,4,6 trimethylbenzoyl-diphenyl-phosphine oxide, 2, 4,6-trimethylbenzoylphenyl phosphinate, 1-hydroxy-cyclohexyl-phenyl-ketone, bis (2,6-dimethoxybenzoyl) -2,4,4 trimethyl-pentyl phosphine oxide, l- [4- (2-hydroxyethoxy) -phenyl] - 2-hydroxy-2methyl-1-propane-1-one, 2,2-dimethoxy-1,2,2-diphenylethan-l-one, 2-methyl-1 [4 (methylthio) phenyl] -2-morpholinopropan- 1- one, 2,4-diethylthioxanthone, their derivatives, and mixtures thereof.
    The aforementioned constituents are carried in a solvent which can be chosen, without limitation, from esters such as ethyl acetate, propyl acetate, butyl acetate, isobutyl propionate, propylene glycol monomethyl ether, methyl lactate, ethyl lactate and gamma-butyrolactone; alkyl phosphates such as triethylphosphate; alkyl carbonates such as dimethyl carbonate; ketones such as acetone, acetylacetone, methyl isobutyl ketone, 2-butanone, 2-pentanone, 2-heptanone, 3-heptanone, cyclopentanone and cyclohexanone; amides such as dimethyl formamide (DMF) or dimethylacetamide (DMAc); sulfur solvents such as dimethyl sulfoxide (DMSO); halogenated solvents such as chloroform, carbon tetrachloride and halogenated alkanes; and their mixtures. It is preferred in this invention to use 2-butanone, cyclohexanone, dimethylsulfoxide, propylene glycol monomethyl ether, triethylphosphate, dimethylacetamide, and mixtures thereof.
    Once the ink obtained from the constituents described above, it is applied in the form of a film to a substrate which can be of any kind and in particular consists of one or more layers of glass or metallic or organic (in particular polymeric). The copolymer used according to the invention has indeed sufficient mechanical properties to allow it to be able to be formed into a film. This film shaping can be done for example: by pouring ink; by centrifugation deposition of the ink; by immersion in ink; or by printing ink, in particular by ink jet or screen printing. The films thus obtained, after a drying step and then optionally an annealing step (in particular at a temperature of 70 to 140 ° C), have good mechanical properties and can if necessary be stretched. Their thickness may for example be between 10 nm and 100 μm, preferably between 50 nm and 50 μm and more preferably between 100 nm and 10 μm.
    Before this film forming step, it is possible to add various additives to the crosslinkable ink, such as reinforcing fillers, conductive fillers such as carbon nanotubes, conductive salts, piezoelectric particles such as nanoparticles. piezo-, ferro- or pyroelectric, such as PZT ceramics or BaTiCh, plasticizers, adhesion promoters and mixtures thereof.
    It is also possible to add to the ink, after reaction of the triethylamine with the copolymer according to the invention, one or more other copolymers according to the invention, identical to, or different from, that reacted with the triethylamine. In this case, it will generally be ensured that this additional copolymer represents at most 60% by weight relative to the total weight of copolymers according to the invention (modified and unmodified) present in the ink.
    The film obtained is then subjected to UV irradiation in order to perfect the crosslinking of the copolymer. It is possible to use for this purpose any technique known to those skilled in the art and in particular irradiation by a mercury vapor arc lamp.
    The crosslinked copolymers obtained according to the invention have a semi-crystalline character.
    Their melting temperature is generally between 100 and 160 ° C, more particularly between 105 and 155 ° C. The melting temperature is measured by differential scanning calorimetry (DSC) on a polymer sample of 5 to 20 mg. This technique consists of measuring the differences in heat exchange between the sample to be analyzed and a reference. It makes it possible to determine the phase transitions, including in particular the melting temperature, and the enthalpies corresponding to these phenomena. For the copolymers of the invention, the temperature range swept is from -20 ° C to 200 ° C, at a speed of 10 ° C per minute. At least 2 cycles are carried out (2 heatings and 2 coolings). The melting temperature is conventionally the maximum value of the melting peak.
    These copolymers also satisfy at least one criterion which qualifies them as electroactive polymers, in particular they have a Curie temperature below their melting point, for example between 20 and 145 ° C., and a maximum of higher dielectric constant. to 30.
    These copolymers advantageously have a coercive field less than 60 MV / m, an electrical permittivity greater than 10 at 25 ° C and 1 kHz and / or a saturation polarization greater than 30 mC / m 2 .
    In addition, due to their crosslinking, these copolymers also exhibit resistance to solvents such as those listed above, resulting in a loss of less than 20% of the mass of the film obtained according to the invention, after immersion for five minutes. at room temperature in these solvents. It is thus possible to use this film in a photolithography process, in which the UV irradiation step described above is carried out in the presence of a mask, so as to crosslink certain parts of the film only, after which the uncrosslinked areas can be selectively removed using a solvent in the development stage.
    The films obtained according to the invention are useful for the manufacture of (opto) electronic devices, including thin film transistors, light transistors, field effect transistors and capacitors; haptic devices;
    actuators; electromechanical microsystems (MEMS); sensors; orientable catheters; Braille keyboards; acoustic devices (speakers or “tweeters”); electrocaloric devices; energy recovery devices, for example. We prefer to use these films in transistors. In the field of printed organic electronics, the film according to the invention according to the invention can in particular be used for the manufacture of the gate dielectric layer of a field effect transistor.
    Due to the aforementioned properties of the crosslinked copolymer forming the films according to the invention, these can have advantageous characteristics in the above applications and in particular low leakage current densities, high breakdown voltages, values of high capacitance, low operating voltages (typically less than 40V, or even 30V or 20V) and / or low hysteresis.
    权利要求:
    Claims (10)
    [1" id="c-fr-0001]
    1. Process for the preparation of a crosslinked fluoropolymer film, comprising the successive steps of:
    (1) formulation of an ink containing, preferably consisting of: (a) at least one fluorinated copolymer obtained by radical copolymerization of monomers comprising, and preferably consisting of: (i) vinylidene fluoride (VDF), (ii ) trifluoroethylene (TrFE), (iii) at least one chlorinated monomer of formula CXCl = CXiX2 where X, Xi and X2 independently denote H, F or CF3, it being understood that at most one of X, Xi and X2 denotes CF3 ; (b) triethylamine; (c) at least one crosslinking agent; (d) at least one photo-initiator; and (e) at least one organic solvent;
    [2" id="c-fr-0002]
    (2) applying said ink as a film to a substrate; and (3) UV irradiation of said film.
    2. Method according to claim 1, characterized in that the chlorinated monomer is chlorotrifluoroethylene (CTFE) or chlorofluoroethylene (CFE).
    [0003]
    3. Method according to claim 1 or 2, characterized in that the proportion of units from TrFE ranges from 5 to 95 mol.% And preferably from 15 to 55 mol.%, Relative to the sum of the units from VDF and TrFE.
    [0004]
    4. Method according to any one of claims 1 to 3, characterized in that the proportion of units originating from the chlorinated monomer varies from 1 to 20 mol.%, In particular from 5 to 15 mol.%, Relative to the whole motifs.
    [0005]
    5. Method according to any one of claims 1 to 4, characterized in that the units derived from an additional monomer possibly present represent from 0 to 20 mol.% And preferably from 5 to 15 mol.%, Relative to all of the patterns.
    [0006]
    6. Method according to any one of claims 1 to 3, characterized in that the crosslinking agent is chosen from monomers or oligomers carrying at least two reactive (meth) acrylic functions in radical polymerization, which can optionally further comprise at least one other function chosen from hydroxyl, ester, ether, urethane, epoxy, cyanurate or iso-cyanurate functions.
    [0007]
    7. Method according to any one of claims 1 to 6, characterized in that the organic solvent is chosen from: esters such as ethyl acetate, propyl acetate, butyl acetate, propionate isobutyl, propylene glycol monomethyl ether, methyl lactate, ethyl lactate and gamma-butyrolactone; alkyl phosphates such as triethylphosphate; alkyl carbonates such as dimethyl carbonate; ketones such as acetone, acetylacetone, methyl isobutyl ketone, 2-butanone, 2-pentanone, 2-heptanone, 3-heptanone, cyclopentanone and cyclohexanone; amides such as dimethyl formamide (DMF) or dimethylacetamide (DMAc); sulfur solvents such as dimethyl sulfoxide (DMSO); halogenated solvents such as chloroform, carbon tetrachloride and halogenated alkanes; and mixtures thereof, preferably 2-butanone, cyclohexanone, dimethylsulfoxide, propylene glycol monomethyl ether, triethylphosphate, dimethylacetamide, and mixtures thereof.
    [0008]
    8. Film of crosslinked fluoropolymer obtained according to the process according to any one of claims 1 to 7.
    [0009]
    9. Use of the film according to claim 8 for the manufacture of (opto) electronic devices, including thin film transistors, light transistors, field effect transistors and capacitors; haptic devices; actuators; electromechanical microsystems (MEMS); sensors; orientable catheters; Braille keyboards; acoustic devices (speakers or “tweeters”); electrocaloric devices; energy recovery devices, preferably in the manufacture of transistors.
    [0010]
    10. Use of the film according to claim 8 as a gate dielectric layer in a field effect transistor.
    类似技术:
    公开号 | 公开日 | 专利标题
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    WO2015200872A1|2014-06-26|2015-12-30|Polyera Corporation|Photopatternable compositions, patterned high k thin film dielectrics and related devices|
    GB888766A|1959-08-04|1962-02-07|Du Pont|Improvements in or relating to fluorinated copolymers, their production and cured products obtained therefrom|
    US4128517A|1977-11-01|1978-12-05|Pennwalt Corporation|Method of washing polymer latices by aerating|
    USH1055H|1990-05-29|1992-05-05|Atochem North America, Inc.|Thermal energy coagulation and washing of latex particles|
    IT1295535B1|1996-07-01|1999-05-12|Ausimont Spa|VINYLIDENFLUORIDE POLYMERIZATION PROCESS|
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    FR3004185B1|2013-04-03|2017-10-13|Arkema France|TERPOLYMERS CONTAINING VINYLIDENE FLUORIDE AND TRIFLUOROETHYLENE|
    CN103387682B|2013-04-16|2015-05-13|西安交通大学|Preparation method for crosslinkable high voltage-resistant high-energy density polyvinylidene fluoride plastic film|
    FR3043836B1|2015-11-17|2019-08-02|Commissariat A L'energie Atomique Et Aux Energies Alternatives|ELECTRONIC DEVICE AND METHOD FOR MANUFACTURING THE SAME|FR3104583A1|2019-12-13|2021-06-18|Arkema France|Electrocaloric polymer, ink and film including and associated uses|
    WO2021116618A1|2019-12-13|2021-06-17|Arkema France|Electrocaloric polymer, ink and film comprising same, and uses thereof|
    JP2022035700A|2020-08-21|2022-03-04|国立大学法人山形大学|Resin inks and electronic devices|
    法律状态:
    2019-02-01| PLSC| Search report ready|Effective date: 20190201 |
    2019-06-19| PLFP| Fee payment|Year of fee payment: 3 |
    2020-06-11| PLFP| Fee payment|Year of fee payment: 4 |
    2021-06-11| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
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    FR1757202A|FR3069544B1|2017-07-28|2017-07-28|PROCESS FOR THE PREPARATION OF A CROSSLINKED FLUORINATED POLYMER FILM|
    FR1757202|2017-07-28|FR1757202A| FR3069544B1|2017-07-28|2017-07-28|PROCESS FOR THE PREPARATION OF A CROSSLINKED FLUORINATED POLYMER FILM|
    PCT/FR2018/051818| WO2019020906A1|2017-07-28|2018-07-17|Method for preparing a cross-linked fluorinated polymer film|
    EP18755522.2A| EP3658595A1|2017-07-28|2018-07-17|Method for preparing a cross-linked fluorinated polymer film|
    CN201880045663.1A| CN111094368A|2017-07-28|2018-07-17|Process for the preparation of cross-linked fluorinated polymer membranes|
    JP2019568326A| JP2020529482A|2017-07-28|2018-07-17|Methods for Preparing Crosslinked Fluorinated Polymer Films|
    US16/633,297| US20200157365A1|2017-07-28|2018-07-17|Method for preparing a cross-linked fluorinated polymer film|
    KR1020207003816A| KR20200039686A|2017-07-28|2018-07-17|Method for preparing a crosslinked fluorinated polymer film|
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