Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F214/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
  • C08F214/18—Monomers containing fluorine
  • C08F214/26—Tetrafluoroethene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F6/00—Post-polymerisation treatments
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/12—Powdering or granulating
  • C08J3/16—Powdering or granulating by coagulating dispersions
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
  • C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
  • C08L27/18—Homopolymers or copolymers or tetrafluoroethene

Definitions

• the present invention relates to a method for producing a refined powder of a fluorine-containing copolymer.
• Heat-melting fluorine-containing copolymers have excellent physical properties such as electrical properties, water and oil repellency, chemical resistance, and heat resistance. (See Patent Document 1). Such powders are directly molded and processed into molded articles, dispersed in a dispersion medium such as water and used as a dispersion liquid, or added to other resin varnishes for use.
• An object of the present invention is to provide a method for producing a refined powder of a hot-melt fluorine-containing copolymer which is excellent in handleability.
• the present invention has the following aspects.
• a powder formed from a heat-fusible fluorine-containing copolymer obtained by radically polymerizing tetrafluoroethylene and other monomers that copolymerize with tetrafluoroethylene in a polymerization medium is heated under a reduced pressure atmosphere.
• the purified powder of the fluorocopolymer is obtained by fluidizing in a temperature range of -170°C or higher melting point of the fluorocopolymer and -50°C or lower melting point of the fluorocopolymer.
• Method [2] The production method of [1], wherein the fluorine-containing copolymer has a melting point of 200°C or higher and 320°C or lower.
• [3] The production method of [1] or [2], wherein the other monomer is at least one monomer selected from the group consisting of ethylene, perfluoro(alkyl vinyl ether) and hexafluoropropylene.
• the fluorine-containing copolymer is a fluorine-containing copolymer having an oxygen-containing polar group.
• the powder has an average particle size of 100 ⁇ m or more and 5 mm or less.
• [6] The production method according to any one of [1] to [4], wherein the powder has an average particle size of 0.1 ⁇ m or more and 25 ⁇ m or less.
• a method for producing a powder composition comprising mixing the refined powder obtained by the production method according to any one of [1] to [10] with another powder to obtain a powder composition.
• a method for producing a liquid composition comprising mixing the purified powder obtained by the production method according to any one of [1] to [10] with a liquid dispersion medium to obtain a liquid composition.
• the production method of [12] wherein the content of the refined powder is 20 to 80% by mass.
• the production method of [12], wherein the liquid composition has a viscosity of 100 mPa ⁇ s or less.
• a method for producing a liquid composition comprising mixing the refined powder obtained by the production method according to any one of [1] to [10] with a varnish of another resin to obtain a liquid composition.
• Average particle diameter (D50) is the volume-based cumulative 50% diameter of the powder determined by a laser diffraction/scattering method. That is, the particle size distribution of the powder is measured by a laser diffraction/scattering method, and the cumulative curve is obtained with the total volume of the powder as 100%.
• D90 is the volume-based cumulative 90% diameter of the powder measured in the same manner.
• Full width at half maximum is the width of the peak at half the height (maximum value) of the peak in the particle size distribution curve of the object.
• the “melting point (melting temperature) of a polymer” is the temperature corresponding to the maximum melting peak measured by differential scanning calorimetry (DSC).
• a "glass transition point of a polymer” is a value measured by analyzing a polymer by a dynamic viscoelasticity measurement (DMA) method.
• the production method of the present invention (hereinafter also referred to as “this method”) comprises tetrafluoroethylene (hereinafter also referred to as TFE) and other monomers that copolymerize with TFE (hereinafter referred to as “other monomers”).
• a powder (hereinafter also referred to as “original powder”) formed from a hot-melt fluorine-containing copolymer (hereinafter also referred to as “F polymer”) obtained by radically polymerizing in a polymerization medium ) is fluidized in a temperature range of -170°C or higher and Tm -50°C or lower, the melting point of the F polymer (hereinafter also referred to as “Tm”) under a reduced pressure atmosphere.
• a purified powder of F polymer having excellent handleability can be obtained.
• the F polymer can suppress contamination of the molding apparatus during its molding, or can suppress corrosiveness when a liquid composition is prepared from it or added to another resin varnish. Powder is obtained efficiently.
• the powder (original powder) formed from the F polymer obtained by radically polymerizing TFE and other monomers copolymerized with TFE in the polymerization medium contains oligomers and low-molecular-weight compounds derived from agents used. presumed to be included. The reason for this is that the F polymer obtained by radical polymerization exhibits a certain molecular weight distribution, and that by-products derived from the agents used, including radical initiators, chain transfer agents, polymerization media, etc. Alternatively, it may occur during exposure to an external environment before and after polymerization, such as exposure to an air atmosphere.
• such a low-molecular-weight compound is contained in the powder, it is thought that the bleed-out of the low-molecular-weight compound over time causes contamination or corrosiveness of the powder, and reduces the handleability of the powder. It is also considered that such a low-molecular-weight compound lowers liquid physical properties such as viscosity of a liquid composition obtained by dispersing the powder in a liquid dispersion medium. It is believed that in this method, such low molecular weight compounds could be removed from the raw powder by volatilization or decomposition under the prescribed heat treatment conditions. In addition, under the heat treatment conditions of this method, the physical properties of the raw powder, including the shape such as the specific surface area, are not impaired, and as a result, it is believed that a refined powder with excellent handleability was efficiently obtained.
• the F polymer in this method is a hot-melt fluorine-containing copolymer obtained by radically polymerizing TFE and other monomers in a polymerization medium.
• the hot-melt polymer means a polymer having a temperature at which the melt flow rate is 1 g/10 min or more and 1000 g/10 min or less under a load of 49 N.
• the melting point (Tm) of the F polymer is preferably 200° C. or higher, more preferably 260° C. or higher, and even more preferably 280° C. or higher.
• the Tm is preferably 320° C. or lower, more preferably 315° C. or lower.
• the glass transition point (hereinafter also referred to as “Tg”) of F polymer is preferably 50° C.
• Tg is preferably 150° C. or lower, more preferably 125° C. or lower, and even more preferably 100° C. or lower.
• the fluorine content of the F polymer is preferably 70 mass % or more, more preferably 72 mass % or more and 76 mass % or less.
• the other monomer is at least one monomer selected from the group consisting of ethylene, perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE”) and hexafluoropropylene (hereinafter also referred to as "HFP")
• PAVE perfluoro(alkyl vinyl ether)
• HFP hexafluoropropylene
• One type of the monomer may be used, or two or more types may be used. Further, a monomer other than the one monomer may be used in combination.
• the F polymer preferably has an oxygen-containing polar group, more preferably a hydroxyl group-containing group or a carbonyl group-containing group, even more preferably a carbonyl group-containing group.
• an F polymer is excellent in dispersibility, miscibility with other components, and adhesion to substrates, but tends to contain low-molecular-weight compounds in its powder preparation. According to the present invention, it is easy to efficiently obtain a purified powder even from such an F polymer.
• the hydroxyl group-containing group is preferably a group containing an alcoholic hydroxyl group, more preferably -CF 2 CH 2 OH and -C(CF 3 ) 2 OH.
• a carbonyl group-containing group includes a carboxyl group, an alkoxycarbonyl group, an amide group, an isocyanate group, a carbamate group (-OC(O)NH 2 ), an acid anhydride residue (-C(O)OC(O)-), an imide Residues (--C(O)NHC(O)--, etc.) and carbonate groups (--OC(O)O--) are preferred, and acid anhydride residues are more preferred.
• the number of oxygen-containing polar groups in the F polymer is preferably 10 to 5,000, more preferably 100 to 3,000 per 1 ⁇ 10 6 carbon atoms in the main chain.
• the number of oxygen-containing polar groups in the F polymer can be quantified by the composition of the polymer or the method described in WO2020/145133.
• the oxygen-containing polar group may be contained in a unit based on a monomer in the F polymer, or may be contained in a terminal group of the main chain of the F polymer, the former being preferred.
• the latter embodiment includes an F polymer having an oxygen-containing polar group as a terminal group derived from a polymerization initiator, a chain transfer agent, or the like.
• the monomer having a carbonyl group-containing group that is copolymerized with TFE is preferably itaconic anhydride, citraconic anhydride and 5-norbornene-2,3-dicarboxylic anhydride (hereinafter also referred to as "NAH"), NAH is more preferred.
• F polymer is a heat-melting fluorine-containing copolymer (ETFE) obtained by radically polymerizing TFE and ethylene in a polymerization medium, and a heat-melting polymer obtained by radically polymerizing TFE and PAVE in a polymerization medium.
• ETFE heat-melting fluorine-containing copolymer
• a hot-melt fluorine-containing copolymer obtained by radically polymerizing TFE and FEP in a polymerization medium, and more preferably PFA.
• a monomer other than ethylene may be further copolymerized for ETFE, a monomer other than PAVE for PFA, and a monomer other than HFP for FEP.
• PFA contains TFE, PAVE, and a monomer having a carbonyl group-containing group in this order in a proportion of 90 to 99 mol%, 0.99 to 9.97 mol%, and 0.01 to 3 mol%, the polymerization medium It is preferably a heat-melting fluorine-containing copolymer obtained by radical polymerization in the medium.
• PFA include fluorine-containing copolymers described in WO 2018/16644.
• PFA is a hot-melt fluorine-containing polymer obtained by radically polymerizing only TFE and PAVE at a ratio of 96 to 99 mol % and 1 to 4 mol % in this order in a polymerization medium containing water. It may be a copolymer.
• the fluorine-containing copolymer may be further treated with fluorine gas.
• PFA include fluorine-containing copolymers described in JP-A-2005-320497.
• ETFE contains TFE, an olefin other than TFE and ethylene, a monomer having a carbonyl group-containing group and ethylene in this order from 40 to 65 mol%, 0.5 to 15 mol%, 0.03 to 3 mol%, 35 It is preferably a hot-melt fluorine-containing copolymer obtained by radical polymerization in a polymerization medium at a ratio of from 50 mol %.
• Specific examples of such ETFE include fluorine-containing copolymers described in International Publication No. 2016/006644.
• PFA powder FluopnPFA P-63, etc.
• ETFE powder which is a powder formed from a hot-melt fluorine-containing copolymer obtained by radical polymerization in a polymerization medium. All of them are manufactured by AGC.
• ETFE powder may be used as the raw powder.
• F polymers are obtained by radically polymerizing TFE and other monomers in a polymerization medium.
• Radical polymerization is preferably carried out in the presence of a radical initiator.
• radical initiators include organic peroxides such as azo compounds, diacyl peroxides, peroxydicarbonates, and peroxyesters, and inorganic peroxides.
• the organic peroxide may be a fluorine-containing organic peroxide.
• Radical polymerization may be carried out in the presence of a chain transfer agent.
• chain transfer agents include alcohols, chlorofluorohydrocarbons, hydrocarbons, perfluorocarbons, acetic acid derivatives, and glycols.
• Radical polymerization may be carried out in the presence of a surfactant.
• surfactants include perfluorocarboxylic acids or salts thereof, and perfluoropolyethers.
• the polymerization medium may be water, a liquid non-aqueous medium, or both. Moreover, you may use together 2 or more types of non-aqueous media.
• the liquid non-aqueous medium at least one liquid non-aqueous medium having 4 to 12 carbon atoms selected from the group consisting of perfluorocarbons, hydrofluorocarbons, chlorohydrofluorocarbons and hydrofluoroethers is preferred.
• the polymerization temperature in radical polymerization is preferably 0° C. or higher and 100° C. or lower, more preferably 20° C. or higher and 90° C. or lower.
• the polymerization pressure in radical polymerization is preferably 0.1 MPa or more and 10 MPa or less, more preferably 0.5 MPa or more and 3 MPa or less.
• the polymerization time is preferably 1 hour or more and 30 hours or less.
• radical polymerization method a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method is preferable.
• Radical polymerization is carried out by an emulsion polymerization method in which TFE and other monomers are radically polymerized in water in the presence of a radical initiator and a surfactant, or TFE and other monomers are polymerized in a non-aqueous medium with a radical initiator. It is preferable to carry out radical polymerization in the presence of a solution polymerization method or a suspension polymerization method.
• the raw powder in this method is powder formed from F polymer.
• the raw powder may be an agglomerated powder of F polymer.
• Agglomerated powder is a powder formed by aggregating individual F polymer particles (primary particles) constituting the powder.
• Such agglomerated powder is preferably obtained by agglomerating F polymer dispersed as primary particles in the polymerization medium obtained by radically polymerizing TFE and other monomers in the polymerization medium.
• the agglomerated powder is preferably a powder obtained by agglomerating the F polymer dispersed as primary particles in the polymerization medium by the action of a flocculant or shearing agitation.
• the raw powder may be a powder formed by further pulverizing such agglomerated powder. In this case, it is easy to adjust the particle size and specific surface area of the raw powder according to the purpose of use. Pulverization is preferably carried out using a mechanical pulverizing device such as a hammer mill, pin mill, disc mill, rotary mill, jet mill and the like.
• the D50 of the raw powder is preferably 0.1 ⁇ m or more and 5 mm or less from the viewpoint of excellent fluidity and easy removal of low-molecular-weight compounds.
• Preferred embodiments include an embodiment in which the D50 of the raw powder is 100 ⁇ m or more and 5 mm or less, and an embodiment in which the D50 is 0.1 ⁇ m or more and 25 ⁇ m.
• the D50 of the raw powder is preferably 500 ⁇ m or more.
• the D50 is preferably 3 mm or less.
• the raw powder in this case is preferably agglomerated powder. Due to the mechanism of action described above, according to the present method, a refined powder can be obtained efficiently without impairing the physical properties of the original powder.
• the D50 of the raw powder is preferably 0.3 ⁇ m or more, more preferably 1 ⁇ m or more.
• the D50 is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less.
• the specific surface area of the raw powder is preferably 1 m 2 /g or more, more preferably 5 m 2 /g or more.
• the specific surface area is preferably 25 m 2 /g or less, more preferably 10 m 2 /g or less.
• the raw powder in this case is preferably a powder obtained by pulverizing the aggregated powder.
• the raw powder is fluidized in a predetermined temperature range under a reduced pressure atmosphere to obtain a refined powder.
• the pressure of the decompressed atmosphere in the treatment is preferably 30 kPa or less, more preferably 20 kPa or less, and even more preferably 10 kPa or less.
• the pressure is preferably 0.1 kPa or higher, more preferably 1 kPa or higher.
• the temperature range for the treatment is Tm-170°C or higher, preferably Tm-140°C or higher.
• the temperature range is Tm-50°C or lower, preferably Tm-100°C or lower.
• the treatment temperature range is preferably 130° C. or higher, more preferably 160° C. or higher.
• the temperature range in this case is preferably 250° C. or lower, more preferably 200° C. or lower.
• the temperature range for the treatment is preferably Tg+50° C. or higher, more preferably Tg+70° C. or higher.
• the temperature range is preferably Tg+120° C. or lower, more preferably Tg+100° C. or lower. In the case of such a temperature range, the decomposition and volatilization of the low molecular weight compounds contained in the raw powder are promoted, and it is easy to efficiently obtain a refined powder with excellent handleability while maintaining the physical properties of the raw powder including the shape.
• the treatment temperature range is preferably 130° C. or higher, more preferably 160° C. or higher.
• the temperature range in this case is preferably 250° C. or lower, more preferably 200° C. or lower.
• Fluidization in the process is preferably accomplished by vibrating or rotating the raw powder.
• Equipment used for treatment includes Nauta mixer, conical dryer, box dryer, band dryer, tunnel dryer, jet dryer, moving bed dryer, rotary dryer, fluidized bed dryer, and flash dryer.
• the treatment time is preferably 20 minutes or longer, more preferably 1 hour or longer.
• the treatment time is preferably 10 hours or less, more preferably 5 hours or less.
• the refined powder obtained by this method is an F-polymer powder with reduced contamination, corrosiveness, etc., and excellent handling properties.
• Specific aspects of the purified powder include perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, and perfluorononanoic acid by liquid chromatography tandem mass spectrometry specified in CEN/TS15968.
• the total content of perfluorocarboxylic acids is less than 100 ppb.
• the content of each of the perfluorocarboxylic acids in the powder form is preferably less than 5 ppb.
• the lower limit of the content of each of the perfluorocarboxylic acids in the powder form is preferably 0 ppb.
• Preferred embodiments of the D50 of the refined powder include an embodiment in which the D50 of the refined powder is 100 ⁇ m or more and 5 mm or less and an embodiment in which the D50 is 0.1 ⁇ m or more and 25 ⁇ m.
• D50 of the refined powder is preferably 500 ⁇ m or more.
• the D50 is preferably 3 mm or less.
• the refined powder may be an agglomerated powder.
• D50 of the refined powder is preferably 0.3 ⁇ m or more, more preferably 1 ⁇ m or more.
• the D50 is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less.
• the specific surface area of the refined powder is preferably 1 m 2 /g or more, more preferably 5 m 2 /g or more.
• the specific surface area is preferably 25 m 2 /g or less, more preferably 10 m 2 /g or less.
• a refined powder can be efficiently obtained in which the physical properties (specific surface area, particle size distribution, etc.) of the raw powder including the shape are highly retained.
• a refined powder having a unimodal particle size distribution can easily be obtained from a raw powder having a unimodal particle size distribution.
• the full width at half maximum of the particle size distribution of both powders is preferably 0.5 ⁇ m or more and 3.5 ⁇ m or less, more preferably 1 ⁇ m or more and 2.5 ⁇ m or less.
• the refined powder obtained by this method has a handleability suitable for complicated and precise conditions of use, and is useful as a powder for forming moldings such as films.
• a molded product such as a film can be obtained by subjecting a powder composition containing such a refined powder to melt extrusion molding or melt injection molding. Also, the refined powder can be subjected to powder coating. Since the refined powder is excellent in handleability due to the mechanism of action described above, it is less likely to contaminate the molding apparatus during such use.
• the refined powder obtained by this method may be used for molding as it is, or may be mixed with other materials and used for molding.
• a powder composition is obtained by mixing the refined powder with other powders.
• Other powders include inorganic powders and powders of resins other than F polymer.
• the inorganic powder is preferably carbon powder, elemental metal powder, inorganic nitride powder or inorganic oxide powder, and includes carbon fiber powder, boron nitride powder, aluminum nitride powder, beryllia powder, silica powder, wollastonite powder, talc powder, Steatite powder, cerium oxide powder, aluminum oxide powder, magnesium oxide powder, zinc oxide powder or titanium oxide powder are preferred.
• silica powder include "ADMAFINE” series (manufactured by Admatechs), "SFP” series (manufactured by Denka), and "E-SPHERES” series (manufactured by Taiheiyo Cement).
• the zinc oxide powder examples include "FINEX” series (manufactured by Sakai Chemical Industry Co., Ltd.).
• Specific examples of the titanium oxide powder include the “Tipaque” series (manufactured by Ishihara Sangyo Co., Ltd.) and the “JMT” series (manufactured by Tayca Corporation).
• Specific examples of talc powder include “SG” series (manufactured by Nippon Talc Co., Ltd.).
• a specific example of the steatite powder is the "BST” series (manufactured by Nippon Talc Co., Ltd.).
• boron nitride powder examples include “UHP” series (manufactured by Showa Denko KK) and “GP” and “HGP” grades of the “Denka Boron Nitride” series (manufactured by Denka).
• Specific examples of the single metal powder include copper powder, silver powder, nickel powder, aluminum powder, gold powder, tin powder, and alloy powder thereof.
• resin powders include polyester resin powder (liquid crystal polyester powder, etc.), imide resin powder, epoxy resin powder, maleimide resin powder, urethane resin powder, polyphenylene ether resin powder, polyphenylene oxide resin powder, polyphenylene sulfide resin powder, Polytetrafluoroethylene powder may be mentioned.
• the shape of other powders is preferably spherical, needle-like, fibrous or plate-like.
• D50 of other powders is preferably 20 ⁇ m or less, more preferably 10 ⁇ m or less.
• D50 is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more.
• the surface of other powders may be surface-treated with a silane coupling agent.
• Silane coupling agents include 3-aminopropyltriethoxysilane, vinyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3- Isocyanatopropyltriethoxysilane can be mentioned.
• the purified powder obtained by this method may be mixed with a liquid dispersion medium to form a liquid composition and then subjected to molding.
• a liquid composition containing the purified powder and the liquid dispersion medium can be obtained.
• the purified powder is preferably dispersed in a liquid dispersion medium.
• Such a liquid composition is, in other words, perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, according to the liquid chromatography tandem mass spectrometry method specified in CEN/TS15968.
• perfluorodecanoic acid perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid and perfluorotetradecanoic acid. It can also be said that it is a composition.
• Such a liquid composition is placed on the surface of a base material, heated to remove the liquid dispersion medium, and further heated to calcine the F polymer.
• a laminate having a layer containing the object is obtained.
• base materials include metal substrates, heat-resistant resin films, prepreg substrates, ceramic substrates, glass substrates, and fibers.
• the method for disposing the liquid composition include a coating method, a droplet discharge method, and an immersion method, and roll coating, knife coating, bar coating, die coating, and spraying are preferred.
• the heating conditions for removing the liquid dispersion medium and firing the F polymer may be appropriately set. Purified powders are excellent in handleability due to the mechanism of action described above, and are less likely to corrode substrates during such use.
• the liquid dispersion medium is a compound that is liquid at 25° C. under atmospheric pressure and is preferably selected from the group consisting of water, amides, ketones and esters.
• Amides include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropanamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy- N,N-dimethylpropanamide, N,N-diethylformamide, hexamethylphosphorictriamide, 1,3-dimethyl-2-imidazolidinone.
• Ketones include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl isopentyl ketone, 2-heptanone, cyclopentanone, cyclohexanone, cycloheptanone.
• Esters include methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethyl 3-ethoxypropionate, ⁇ -butyrolactone, ⁇ - Valerolactone can be mentioned.
• the liquid composition may further comprise inorganic powders or resins different from the F-polymer.
• the inorganic powder include the inorganic powders described above. Silver powder and copper powder are preferable as the single metal powder.
• the different resin is preferably an aromatic polymer, more preferably an aromatic polyimide, an aromatic polyamic acid, an aromatic polyamideimide, or a precursor of an aromatic polyamideimide. Specific examples of such different resins include the “Upia-AT” series (manufactured by UBE), the “Neoprim (registered trademark)” series (manufactured by Mitsubishi Gas Chemical Company), and the “Spixeria (registered trademark)” series (manufactured by Somar).
• the liquid composition may further contain a nonionic surfactant.
• nonionic surfactants include "Futergent” series (manufactured by Neos), “Surflon” series (manufactured by AGC Seimi Chemical), “Megafac” series (manufactured by DIC), “Unidyne” series (manufactured by DIC).
• the absolute value of the fluctuation range of the pH of the liquid composition is preferably 3 or less, more preferably 2 or less.
• the range of pH fluctuation means the range of pH fluctuation before and after standing when the liquid composition is left at 25° C. for 3 months, and is considered to correlate with the corrosiveness of the refined powder.
• the content of the purified powder in the liquid composition is preferably 20-80% by mass, more preferably 35-75% by mass, and particularly preferably 40-70% by mass.
• the content of the liquid dispersion medium in the liquid composition is preferably 20 to 80% by mass, more preferably 25 to 65% by mass, and particularly preferably 30 to 60% by mass. Even if the content of the refined powder in the liquid composition is high, the liquid composition is excellent in liquid physical properties such as viscosity due to the mechanism of action described above.
• the viscosity of the liquid composition is preferably 5000 mPa ⁇ s or less, more preferably 1000 mPa ⁇ s or less, even more preferably 100 mPa ⁇ s or less, and particularly preferably 50 mPa ⁇ s or less.
• the lower limit of the viscosity of the liquid composition is preferably 1 mPa ⁇ s.
• the thixotropic ratio of the liquid composition is preferably 2.0 or less, more preferably 1.4 or less, even more preferably 1.3 or less.
• the lower limit of the thixotropic ratio of the liquid composition is preferably 1.0.
• the “viscosity of the liquid composition” is a value measured using a Brookfield viscometer at 25° C. and a rotation speed of 30 rpm.
• the measurement is repeated 3 times, and the average value of the 3 measurements is taken.
• the "thixotropic ratio of the liquid composition” is a value calculated by dividing the viscosity ⁇ 1 measured at a rotation speed of 30 rpm by the viscosity ⁇ 2 measured at a rotation speed of 60 rpm. . Each viscosity measurement is repeated three times, and the average value of the three measurements is taken.
• the refined powder obtained by this method may be mixed with other resin varnish and subjected to molding.
• a liquid composition containing the refined powder, the other resin, and the liquid dispersion medium derived from the varnish of the other resin can be obtained.
• Other resins and solvents constituting the varnish include the above-mentioned other resins and liquid dispersion media, respectively.
• Such a liquid composition may further contain other components such as inorganic powders and surfactants that may be contained in the liquid composition obtained by mixing the above-described purified powder and liquid dispersion medium.
• a dehydrating agent an antifoaming agent, a plasticizer, a weathering agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a brightener, and a colorant may be added.
• a conductive agent, a release agent, a surface treatment agent, a flame retardant, an organic filler, and other additives may be added.
• Molded articles obtained from the refined powder include antenna parts, printed circuit boards, aircraft parts, automobile parts, sporting goods, food industry goods, heat dissipation parts, paints, and cosmetics.
• electric wire coating materials wires for aircraft, etc.
• enameled wire coating materials used for motors such as electric vehicles, electrical insulating tapes, insulating tapes for oil drilling, oil transportation hoses, hydrogen tanks, printed circuit boards materials, separation membranes (microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, ion exchange membranes, dialysis membranes, gas separation membranes, etc.), electrode binders (for lithium secondary batteries, fuel cells, etc.), copy rolls, Furniture, automobile dashboards, home appliance covers, sliding parts (load bearings, yaw bearings, slide shafts, valves, bearings, bushes, seals, thrust washers, wear rings, pistons, slide switches, gears, cams, belt conveyors , food conveyor belts, etc.), tension ropes, wear pads, wear strips, tube ramps,
• the liquid composition prepared from the refined powder is useful as a coating material for imparting low dielectric properties, insulation, heat resistance, corrosion resistance, chemical resistance, water resistance, impact resistance, and thermal conductivity.
• the liquid composition is used for printed wiring boards, solder resists, thermal interface materials, substrates for power modules, coils used in power devices such as motors, in-vehicle engines, heat exchangers, vials, syringes ( syringe), ampoule, medical wire, secondary battery such as lithium ion battery, primary battery such as lithium battery, radical battery, solar battery, fuel cell, lithium ion capacitor, hybrid capacitor, capacitor, capacitor (aluminum electrolytic capacitor, tantalum) electrolytic capacitors, etc.), electrochromic elements, electrochemical switching elements, electrode binders, electrode separators, and electrodes (positive and negative electrodes).
• Liquid compositions prepared from refined powders are also useful as adhesives to bond parts together.
• a liquid composition can be used for adhesion of ceramic parts, adhesion of metal parts, adhesion of electronic parts such as IC chips, resistors and capacitors on substrates of semiconductor elements and module parts, adhesion of circuit boards and heat sinks, It can be used for bonding LED chips to substrates.
• the liquid composition further containing a conductive filler can be suitably used in applications requiring conductivity, such as the field of printed electronics.
• printed circuit boards Specifically, printed circuit boards, semiconductor die attach materials, sensor electrodes, displays, backplanes, RFID (radio frequency identification), photovoltaics, lighting, disposable electronics, automotive heaters, electromagnetic wave (EMI) shielding, membranes It can be used in the manufacture of current-carrying elements in switches and the like.
• RFID radio frequency identification
• photovoltaics lighting, disposable electronics, automotive heaters, electromagnetic wave (EMI) shielding, membranes It can be used in the manufacture of current-carrying elements in switches and the like.
• EMI electromagnetic wave
• Liquid compositions prepared from refined powders are also useful as fiber sizing agents.
• the liquid composition is placed on the surface of the fiber and the liquid dispersion medium is allowed to evaporate, resulting in a sized fiber with surface-attached F-polymer.
• the F polymer may be baked by further heating to obtain a sized fiber to which the baked product of the F polymer adheres to the surface.
• Fibers include glass fibers such as E glass, D glass, L glass, S glass, T glass, Q glass, UN glass, NE glass, spherical glass; aramid fiber, polyolefin fiber, modified polyphenylene ether fiber, vinylon fiber, rayon organic fibers such as fibers, polyester fibers and natural fibers; boron fibers, carbon fibers and metal fibers; carbon fibers are preferred.
• the present method is not limited to the configurations of the above-described embodiments.
• the present method may add any other configuration to the configuration of the above embodiment, or replace it with any configuration that exhibits a similar function.
• the method for producing a powder composition or liquid composition containing the refined powder obtained by the present method may additionally have any other configuration in the configuration of the above embodiment, or may have the same function may be substituted with any configuration that exhibits
• an AE-3000 solution containing 0.05% by mass of bis(perfluorobutyryl)peroxide as a radical initiator was pressurized into the polymerization tank to initiate polymerization, and the internal pressure of the polymerization tank was kept constant at 1.0 MPa.
• TFE gas was injected into the chamber to continue the polymerization.
• the above AE-3000 solution was intermittently pressurized into the polymerization vessel so that the TFE gas consumption rate was 0.5 g/min.
• 1 mL of AE-3000 solution containing 1% by mass of NAH was pressurized into the polymerization tank.
• Polymerization crude liquid 1 contains 98.0 mol %, 1.9 mol % and 0.1 mol % of TFE units, PPVE units and NAH units in this order, and F polymer 1 having an oxygen-containing polar group (Tm: 300 ° C., Tg: 95° C.) in an amount of 13% by mass, and the primary particles of F-Polymer 1 were dispersed in the liquid.
• Raw powder 11 is pulverized using a counter jet mill (manufactured by Hosokawa Micron Corporation) under conditions of a grind pressure and a push pressure of 0.65 MPa to obtain raw powder 12 (D50: 2.0 ⁇ m, specific surface area: 8 m 2 /g). got The particle size distribution of the raw powder 12 was unimodal and its full width at half maximum was 2.1 ⁇ m.
• Example 2 First, a glass polymerization tank (inner volume: 1 L) was charged with 530 g of deionized water as a polymerization medium, 55 g of ammonium perfluorohexanoate as a surfactant, and 30 g of paraffin wax. The inside of the polymerization vessel was degassed, and TFE gas was introduced while maintaining the internal temperature of the polymerization vessel at 85° C., and 0.03 g of ethane gas as a chain transfer agent and 8.8 g of PPVE were charged. Furthermore, the inside of the polymerization vessel was stirred, and TFE gas was injected until the internal pressure of the polymerization vessel reached 0.83 MPa.
• an aqueous solution prepared by dissolving 0.11 g of ammonium sulfate, which is a radical initiator, in 20 g of deionized water is injected into the polymerization tank to initiate polymerization, and TFE gas is added so that the internal pressure of the polymerization tank is constant at 0.93 MPa. was pressed in to continue the polymerization. After the polymerization was continued until 120 g of TFE had finished reacting, TFE gas was purged from the polymerization tank to atmospheric pressure. The contents of the polymerization tank were taken out and cooled, and the supernatant paraffin wax was removed to obtain a crude polymerization liquid 2.
• Polymerization crude liquid 2 contains 18.5% by mass of F polymer 2 (Tm: 305° C.) containing 98.5 mol% of TFE units and 1.5 mol% of PPVE units in this order. It was a polymerization crude liquid in which particles were dispersed in the liquid.
• Raw powder 21 (D50: 2.4 ⁇ m), which is an agglomerated powder obtained by aggregating the primary particles of F polymer 2, was obtained from polymerization crude liquid 2 .
• Example 3 Production of refined powder [Example 3]
• the raw powder 11 is held in a conical vacuum dryer (manufactured by Seishin Enterprise Co., Ltd.) under a reduced pressure atmosphere of 5 kPa at 180 ° C. for 3 hours while being fluidized to obtain a refined powder 11 (D50: 1 .5 mm) was obtained.
• the flow was performed by rotating the vacuum dryer at 5 rpm.
• Purified powder 12 (D50: 2.4 ⁇ m, specific surface area: 8 m 2 /g) was obtained in the same manner as above, except that raw powder 11 was changed to raw powder 12.
• the particle size distribution of the refined powder 12 was unimodal and its full width at half maximum was 2.1 ⁇ m.
• Purified powder 11 was pulverized using a counter jet mill (manufactured by Hosokawa Micron Corporation) under conditions of a grind pressure and a push pressure of 0.65 MPa to obtain purified powder 13 (D50: 2.0 ⁇ m, specific surface area: 7 m 2 / g) was obtained.
• the particle size distribution of the refined powder 13 was unimodal and its full width at half maximum was 2.1 ⁇ m.
• Each content of perfluorocarboxylic acid measured according to CEN/TS15968 contained in Purified Powder 11, Purified Powder 12 and Purified Powder 13 was below the detection limit of less than 5 ppb.
• Example 4 Purified powder 21 was obtained in the same manner as in Example 3, except that raw powder 11 was changed to raw powder 21.
• the liquid compositions 13L and 13H containing the purified powder 13 exhibited low viscosity and excellent liquid physical properties regardless of the content of the purified powder 13.
• the liquid composition 13H was less thixotropic and superior in thixotropy than the liquid composition 12H.
• the refined powder obtained by the method of the present invention has excellent handling properties suitable for complicated and precise usage conditions, and is free from contamination of molding equipment during molding and corrosiveness when made into a liquid composition. can be suppressed. Therefore, it is useful as a material for moldings of heat-meltable fluorine-containing copolymers.

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