Copolymer, molded article, injection molded article, and coated electric wire

Abstract

The present invention provides a copolymer containing tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, wherein the content of the perfluoro(propyl vinyl ether) units is 4.6% by mass to 5.2% by mass relative to all monomer units, the melt flow rate at 372 °C is 22.0 g / 10 min to 28.0 g / 10 min, and the number of functional groups is 50 or less per 10 6 main chain carbon atoms.

Description

Technical Field

[0001] The present invention relates to a copolymer, a molded article, an injection molded article, and a coated electric wire. Background Art

[0002] Patent Document 1 describes a tetrafluoroethylene copolymer composed of tetrafluoroethylene and a perfluoro(alkyl vinyl ether) represented by the following general formula (I)-

[0003] Rf-O-CF=CF2(I)

[0004] (wherein, Rf represents a perfluoroalkyl group having 1 to 5 carbon atoms), the tetrafluoroethylene copolymer is characterized in that the number of unstable end groups is 10 to 100 per 10 6 carbon atoms, and the total number of -COF and / or -COOH in the above unstable end groups is 10 to 100 per 10 6 carbon atoms.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2005-320497 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] An object of the present invention is to provide a copolymer capable of forming a thin coating layer at a high speed on a small-diameter core wire by an extrusion molding method, capable of obtaining an injection molded article having excellent surface smoothness with high productivity by an injection molding method, and capable of obtaining a molded article having excellent abrasion resistance at 150 ° C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation.

[0010] Means for Solving the Problems

[0011] According to the present invention, there is provided a copolymer containing tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, the content of perfluoro(propyl vinyl ether) units being 4.6% by mass to 5.2% by mass based on all monomer units, the melt flow rate at 372 ° C being 22.0 g / 10 minutes to 28.0 g / 10 minutes, and the number of functional groups being 50 or less per 10 6 main chain carbon atoms.

[0012] Further, according to the present invention, there is provided an injection molded article containing the above copolymer.

[0013] Further, according to the present invention, there is provided a coated electric wire having a coating layer containing the above copolymer.

[0014] In addition, according to the present invention, there is provided a molded article containing the above copolymer, wherein the molded article is a microtube, a container, a piping member, or a wire coating.

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to provide a copolymer that can form a thin coating layer on a small-diameter core wire at a high speed by an extrusion molding method, can obtain an injection molded article with excellent surface smoothness at a high production rate by an injection molding method, and can obtain a molded article with excellent abrasion resistance at 150°C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation. Detailed Description of the Invention

[0017] Hereinafter, the specific embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0018] The copolymer of the present invention contains tetrafluoroethylene (TFE) units and perfluoro(propyl vinyl ether) (PPVE) units.

[0019] In biological or chemical experiments, in order to store a small amount of a sample or centrifuge it, a microtube (microcentrifuge tube) capable of accommodating a small amount of the sample is used. In cases where heat resistance and chemical resistance are particularly required, a microtube made of a fluororesin is used.

[0020] Microtubes are generally cylindrical or conical, with one end open and the other end closed. A cap is attached to the open end. When such a microtube is used for centrifugation at a high temperature of 95°C or higher for a long time, the microtube sometimes deforms. In addition, when a highly reactive chemical is accommodated in such a microtube and centrifuged at a high temperature, the microtube sometimes wears and cracks. On the other hand, in order to manufacture microtubes at a high production rate, a material with excellent moldability is required. In addition, since there are also cases where reagents are stored in microtubes, in order to prevent the reagents from deteriorating, it is preferable to use a material with excellent low reagent permeability so that reagents such as electrolytes are difficult to release to the outside and excellent low carbon dioxide permeability so that carbon dioxide is difficult to invade the inside from the outside.

[0021] Findings: By appropriately adjusting the content, melt flow rate (MFR), and number of functional groups of the PPVE units in the copolymer containing TFE units and PPVE units, the moldability of the copolymer is significantly improved. At the same time, the abrasion resistance at 150 °C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat distortion resistance after reagent impregnation of the molded article formed from such a copolymer can be enhanced. Therefore, by using the copolymer of the present invention, it is possible to obtain a microtube that is less likely to deteriorate the sample and is less likely to deform or crack even when subjected to centrifugation at a high temperature in a state where highly reactive chemicals are contained.

[0022] Furthermore, the copolymer of the present invention can form a thin coating layer at a high speed on a small-diameter core wire by an extrusion molding method. Thus, the copolymer of the present invention can be used not only as a material for valves but also for a wide range of applications such as wire coating.

[0023] The copolymer of the present invention is a fluororesin with melt processability. Melt processability means that the polymer can be melted and processed using existing processing equipment such as an extruder and an injection molding machine.

[0024] The content of the PPVE units in the copolymer is 4.6 mass% to 5.2 mass% relative to all monomer units. The content of the PPVE units in the copolymer is preferably 4.7 mass% or more, more preferably 4.8 mass% or more, further preferably 4.9 mass% or more, particularly preferably 5.0 mass% or more, preferably 5.1 mass% or less, more preferably 5.0 mass% or less. If the content of the PPVE units in the copolymer is too high, a molded article with excellent low carbon dioxide permeability, creep resistance, and thermal rigidity cannot be obtained. If the content of the PPVE units in the copolymer is too low, a molded article with excellent abrasion resistance at 150 °C and heat distortion resistance after reagent impregnation cannot be obtained.

[0025] The content of the TFE units in the copolymer is preferably 94.8 mass% to 95.4 mass% relative to all monomer units, more preferably 94.9 mass% or more, further preferably 95.0 mass% or more, more preferably 95.3 mass% or less, further preferably 95.2 mass% or less, particularly preferably 95.1 mass% or less, and most preferably 95.0 mass% or less. If the content of the TFE units in the copolymer is too low, it may not be possible to obtain a molded article with excellent low carbon dioxide permeability, creep resistance, and thermal rigidity. If the content of the TFE units in the copolymer is too high, it may not be possible to obtain a molded article with excellent abrasion resistance at 150 °C and heat distortion resistance after reagent impregnation.

[0026] In the present invention, the content of each monomer unit in the copolymer is determined by 19 the F-NMR method.

[0027] The copolymer may also contain monomer units derived from monomers capable of copolymerizing with TFE and PPVE. At this time, the content of the monomer units capable of copolymerizing with TFE and PPVE is preferably 0 to 1.5% by mass, more preferably 0.05% to 0.6% by mass, and further preferably 0.1% to 0.3% by mass, based on all the monomer units of the copolymer.

[0028] Examples of the monomers capable of copolymerizing with TFE and PPVE include hexafluoropropylene (HFP), CZ 1 Z 2 = CZ 3 (CF2) n Z 4 (wherein Z 1 , Z 2 and Z 3 are the same or different and represent H or F, and Z 4 represents H, F or Cl, and n represents an integer of 2 to 10) vinyl monomers, CF2 = CF - ORf 1 (wherein Rf 1 is a perfluoroalkyl group having 1 to 8 carbon atoms) perfluoro(alkyl vinyl ether) [PAVE] (excluding PPVE), and CF2 = CF - OCH2 - Rf 1 (wherein Rf 1 represents a perfluoroalkyl group having 1 to 5 carbon atoms.) alkyl perfluoro vinyl ether derivatives and the like. Among them, HFP is preferred.

[0029] As the copolymer, at least one selected from the group consisting of a copolymer composed only of TFE units and PPVE units and a TFE / HFP / PPVE copolymer is preferred, and a copolymer composed only of TFE units and PPVE units is more preferred.

[0030] The melt flow rate (MFR) of the copolymer is 22.0 g / 10 minutes to 28.0 g / 10 minutes. The MFR of the copolymer is preferably 23.0 g / 10 minutes or more, more preferably 23.1 g / 10 minutes or more, and preferably 27.0 g / 10 minutes or less. If the MFR of the copolymer is too high, a molded article having excellent heat resistance to deformation after reagent impregnation cannot be obtained. If the MFR of the copolymer is too low, when the copolymer is injected by an injection molding method, it is difficult to obtain an injection molded article having excellent surface smoothness, or when the copolymer is extruded onto a core wire having a small diameter by an extrusion molding method, coating breakage occurs, or defects occur in the coating layer. In addition, if the MFR of the copolymer is too low, a molded article having excellent low carbon dioxide permeability and low reagent permeability cannot be obtained.

[0031] In the present invention, MFR is a value obtained in the form of the mass (g / 10 minutes) of a polymer flowing out of a nozzle with an inner diameter of 2.1 mm and a length of 8 mm every 10 minutes at 372 °C under a load of 5 kg using a melt index tester in accordance with ASTM D1238.

[0032] The MFR can be adjusted by adjusting the type and amount of the polymerization initiator used in polymerizing the monomer, the type and amount of the chain transfer agent, and the like.

[0033] The number of functional groups per 10 6 main chain carbon atoms of the copolymer is 50 or less. The number of functional groups per 10 6 main chain carbon atoms of the copolymer is preferably 40 or less, more preferably 30 or less, still more preferably 20 or less, even more preferably 15 or less, particularly preferably 10 or less, and most preferably less than 6. By making the number of functional groups of the copolymer within the above range, an injection molded article with excellent surface smoothness can be obtained with high productivity by an injection molding method, a thin coating layer can be formed at a high speed on a core wire with a small diameter by an extrusion molding method, and a molded article with excellent abrasion resistance at 150 °C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation can be obtained. If the number of functional groups of the copolymer is too large, although the low carbon dioxide permeability and creep resistance are excellent, it is difficult to obtain a molded article that exhibits excellent low permeability to reagents such as electrolytes.

[0034] The identification of the type of the above functional group and the determination of the number of functional groups can be carried out using infrared spectroscopic analysis.

[0035] Specifically, regarding the number of functional groups, it is measured by the following method. First, the above copolymer is formed into a film with a thickness of 0.25 mm to 0.3 mm by cold pressing. This film is analyzed by Fourier transform infrared spectroscopy to obtain the infrared absorption spectrum of the above copolymer, and a differential spectrum from a background spectrum of completely fluorinated and free of functional groups is obtained. The number of functional groups N per 1 × 10 6 carbon atoms in the above copolymer is calculated from the absorption peak of a specific functional group shown in the following formula (A) from the differential spectrum.

[0036] N = I × K / t (A)

[0037] I: Absorbance

[0038] K: Correction coefficient

[0039] t: Thickness of the film (mm)

[0040] For reference, absorption frequencies, molar extinction coefficients, and correction coefficients for some functional groups are shown in Table 1. Additionally, the molar extinction coefficient is determined from the FT-IR measurement data of low molecular weight model compounds.

[0041] [Table 1]

[0042] Table 1

[0043]

[0044] The absorption frequency ratios of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, -CH2CONH2 are respectively lower by several tens of wavenumbers (cm -1 ) than those of -CF2H, -COF, free -COOH and bonded -COOH, -COOCH3, -CONH2 shown in the table.

[0045] For example, the number of functional groups of -COF refers to the total number of the number of functional groups obtained from the absorption peak at the absorption frequency of 1883 cm -1 due to -CF2COF and the number of functional groups obtained from the absorption peak at the absorption frequency of 1840 cm -1 due to -CH2COF.

[0046] The functional groups are those present at the ends of the main chain or side chains of the copolymer and those present in the main chain or side chains. The number of functional groups can be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH.

[0047] The above functional groups are introduced into the copolymer, for example, through a chain transfer agent or a polymerization initiator used in the production of the copolymer. For example, when an alcohol is used as a chain transfer agent or a peroxide having a -CH2OH structure is used as a polymerization initiator, -CH2OH is introduced to the end of the main chain of the copolymer. Additionally, by polymerizing a monomer having a functional group, the above functional groups are introduced to the end of the side chain of the copolymer.

[0048] By subjecting the copolymer having such functional groups to a fluorination treatment, a copolymer having the number of functional groups within the above range can be obtained. That is, the copolymer of the present invention is preferably a copolymer after fluorination treatment. The copolymer of the present invention also preferably has a -CF3 end group.

[0049] The melting point of the copolymer is preferably 295°C to 315°C, more preferably 300°C or higher, further preferably 302°C or higher, preferably 308°C or lower, and more preferably 304°C or lower. By setting the melting point within the above range, a copolymer can be obtained that provides a molded article having particularly excellent mechanical properties and sealing properties at high temperatures.

[0050] In the present invention, the melting point can be measured using a differential scanning calorimeter [DSC].

[0051] The carbon dioxide permeability coefficient of the copolymer is preferably 1500 cm 3 ·mm / (m 2 ·24 h·atm) or less. Since the content of the PPVE unit, the melt flow rate (MFR), and the number of functional groups of the copolymer containing the TFE unit and the PPVE unit are appropriately adjusted in the copolymer of the present invention, it has excellent low carbon dioxide permeability. Therefore, by using the copolymer of the present invention, it is possible to form a microtube, a piping member, and a container that can suppress the permeation of carbon dioxide from the outside. Therefore, when an alkaline aqueous solution such as an aqueous sodium hydroxide solution is stored in the microtube for a long time or stays in the piping for a long time, the problem that the purity of the alkaline aqueous solution is reduced due to the reaction of the alkali in the aqueous solution with the carbon dioxide permeating from the outside hardly occurs.

[0052] In the present invention, the carbon dioxide permeability coefficient can be measured under the conditions of a test temperature of 70°C and a test humidity of 0% RH. The specific measurement of the carbon dioxide permeability coefficient can be carried out by the method described in the examples.

[0053] The electrolyte permeability of the copolymer is preferably 7.0 g·cm / m 2 or less, more preferably 6.5 g·cm / m 2 or less. Since the content of the PPVE unit, the melt flow rate (MFR), and the number of functional groups of the copolymer containing the TFE unit and the PPVE unit are appropriately adjusted in the copolymer of the present invention, it has excellent low electrolyte permeability. That is, by using the copolymer of the present invention, a molded body that hardly allows a reagent such as an electrolyte to permeate can be obtained.

[0054] In the present invention, the electrolyte permeability can be measured under the conditions of a temperature of 60°C for 30 days. The specific measurement of the electrolyte permeability can be carried out by the method described in the examples.

[0055] The copolymer of the present invention can be produced by polymerization methods such as suspension polymerization, solution polymerization, emulsion polymerization, and bulk polymerization. As the polymerization method, emulsion polymerization or suspension polymerization is preferred. In these polymerizations, various conditions such as temperature and pressure, polymerization initiators, and other additives can be appropriately set according to the composition and amount of the copolymer.

[0056] As the polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.

[0057] The oil-soluble radical polymerization initiator can be a known oil-soluble peroxide, and the following substances can be cited as representative examples:

[0058] Dialkyl peroxydicarbonates such as di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate;

[0059] Peroxyesters such as tert-butyl peroxyisobutyrate, tert-butyl peroxypivalate;

[0060] Dialkyl peroxides such as di-tert-butyl peroxide;

[0061] Di[fluoro(or fluorochloro)acyl]peroxides; etc.

[0062] As di[fluoro(or fluorochloro)acyl]peroxides, there can be mentioned diacyl peroxides represented by [(RfCOO)-]2 (Rf is a perfluoroalkyl group, ω-hydroperfluoroalkyl group or fluorochloroalkyl group).

[0063] As di[fluoro(or fluorochloro)acyl]peroxides, there can be mentioned, for example, bis(ω-hydro-dodecafluorocaproyl)peroxide, bis(ω-hydro-tetradecafluoroheptanoyl)peroxide, bis(ω-hydro-hexadecafluorononanoyl)peroxide, bis(perfluoropropionyl)peroxide, bis(perfluorobutyryl)peroxide, bis(perfluorovaleryl)peroxide, bis(perfluorohexanoyl)peroxide, bis(perfluoroheptanoyl)peroxide, bis(perfluorooctanoyl)peroxide, bis(perfluorononanoyl)peroxide, bis(ω-chloro-hexafluorobutyryl)peroxide, bis(ω-chloro-decafluorohexanoyl)peroxide, bis(ω-chloro-tetradecafluorooctanoyl)peroxide, ω-hydro-dodecafluoroheptanoyl-ω-hydro-hexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydro-dodecafluoroheptanoyl-perfluorobutyryl-peroxide, bis(dichloropentafluorobutyryl)peroxide, bis(trichlorooctafluorohexanoyl)peroxide, bis(tetrachloroundecafluorooctanoyl)peroxide, bis(pentachlorotetradecafluorodecanoyl)peroxide, bis(undecachlorotriacontafluorodocosanoyl)peroxide, etc.

[0064] The water-soluble radical polymerization initiator can be a known water-soluble peroxide, and there can be mentioned, for example, ammonium salts, potassium salts, sodium salts of persulfuric acid, perboric acid, perchloric acid, perphosphoric acid, percarbonic acid, etc., organic peroxides such as disuccinic peroxide, dipentanedioic peroxide, tert-butyl peroxymaleate, tert-butyl hydroperoxide, etc. It is also possible to use a reducing agent such as sulfites in combination with the peroxide, and the amount used can be 0.1 to 20 times that of the peroxide.

[0065] In the polymerization, a surfactant, a chain transfer agent and a solvent can be used, and substances known in the past can be used respectively.

[0066] As the surfactant, known surfactants can be used, such as nonionic surfactants, anionic surfactants, cationic surfactants, etc. Among them, fluorine-containing anionic surfactants are preferred, and more preferably straight-chain or branched fluorine-containing anionic surfactants having 4 to 20 carbon atoms with or without ether-bonded oxygen (i.e., oxygen atoms can be inserted between carbon atoms). The addition amount of the surfactant (relative to the polymerized water) is preferably 50 ppm to 5000 ppm.

[0067] As the chain transfer agent, for example, hydrocarbons such as ethane, isopentane, n-hexane, cyclohexane; aromatics such as toluene, xylene; ketones such as acetone; acetate esters such as ethyl acetate, butyl acetate; alcohols such as methanol, ethanol; mercaptans such as methyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, chloroform, dichloromethane, chloromethane, etc. can be cited. The addition amount of the chain transfer agent can vary depending on the chain transfer constant of the compound used, and is usually used in the range of 0.01% by mass to 20% by mass relative to the polymerization solvent.

[0068] As the solvent, water, a mixed solvent of water and alcohol, etc. can be cited.

[0069] In suspension polymerization, in addition to water, fluorine-based solvents can also be used. As the fluorine-based solvents, hydrochlorofluorocarbons such as CH3CClF2, CH3CCl2F, CF3CF2CCl2H, CF2ClCF2CFHCl; chlorofluorocarbons such as CF2ClCFClCF2CF3, CF3CFClCFClCF3; hydrofluorocarbons such as CF3CFHCFHCF2CF2CF3, CF2HCF2CF2CF2CF2H, CF3CF2CF2CF2CF2CF2CF2H; hydrofluoroethers such as CH3OC2F5, CH3OC3F5CF3CF2CH2OCHF2, CF3CHFCF2OCH3, CHF2CF2OCH2F, (CF3)2CHCF2OCH3, CF3CF2CH2OCH2CHF2, CF3CHFCF2OCH2CF3; perfluoroalkanes such as perfluorocyclobutane, CF3CF2CF2CF3, CF3CF2CF2CF2CF3, CF3CF2CF2CF2CF2CF3 can be cited. Among them, perfluoroalkanes are preferred. From the aspects of suspension and economy, the amount of the fluorine-based solvent is preferably 10% by mass to 100% by mass relative to the aqueous medium.

[0070] The polymerization temperature is not particularly limited and can be 0 to 100 °C. The polymerization pressure is appropriately determined according to the type, amount and vapor pressure of the solvent used, the polymerization temperature and other polymerization conditions, and can usually be 0 to 9.8 MPaG.

[0071] In the case of obtaining an aqueous dispersion containing a copolymer through a polymerization reaction, the copolymer can be recovered by precipitating the copolymer contained in the aqueous dispersion and then performing washing and drying. Additionally, in the case of obtaining a copolymer in the form of a slurry through a polymerization reaction, the copolymer can be recovered by taking out the slurry from the reaction vessel and then performing washing and drying. The copolymer can be recovered in the form of a powder by drying.

[0072] The copolymer obtained through polymerization can also be formed into pellets. There is no particular limitation on the molding method for forming into pellets, and existing well-known methods can be used. For example, there can be mentioned methods such as melting and extruding the copolymer using a single-screw extruder, a twin-screw extruder, or a tandem extruder and cutting it into a specified length to form pellets. The extrusion temperature during melting and extrusion needs to be changed according to the melt viscosity of the copolymer and the manufacturing method, and it is preferably the melting point of the copolymer + 20°C to the melting point of the copolymer + 140°C. There is no particular limitation on the cutting method of the copolymer, and existing well-known methods such as wire cutting, thermal cutting, underwater cutting, and sheet cutting can be adopted. The volatile components in the pellets can also be removed by heating the obtained pellets (degassing treatment). The obtained pellets can also be treated by contacting them with warm water at 30°C to 200°C, steam at 100°C to 200°C, or hot air at 40°C to 200°C.

[0073] The copolymer obtained through polymerization can also be subjected to a fluorination treatment. The fluorination treatment can be carried out by contacting the non-fluorinated copolymer with a fluorine-containing compound. Through the fluorination treatment, thermally unstable functional groups such as -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, etc. and relatively thermally stable functional groups such as -CF2H in the copolymer can be converted into extremely thermally stable -CF3. As a result, the total number (number of functional groups) of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, and -CF2H in the copolymer can be easily adjusted to the above-mentioned range.

[0074] There is no particular limitation on the fluorine-containing compound, and fluorine radical sources that generate fluorine radicals under fluorination treatment conditions can be mentioned. As the above-mentioned fluorine radical sources, there can be mentioned F2 gas, CoF3, AgF2, UF6, OF2, N2F2, CF3OF, halogen fluorides (such as IF5, ClF3), etc.

[0075] Fluorine radical sources such as F2 gas can be at a 100% concentration, but from the aspect of safety, it is preferably mixed with an inert gas and diluted to 5% by mass to 50% by mass for use, and more preferably diluted to 15% by mass to 30% by mass for use. As the above-mentioned inert gas, there can be mentioned nitrogen, helium, argon, etc., and from the aspect of economy, nitrogen is preferred.

[0076] The conditions for the fluorination treatment are not particularly limited. The molten copolymer can be contacted with a fluorine-containing compound, but generally, it can be carried out at a temperature below the melting point of the copolymer, preferably at 20°C to 240°C, more preferably at 100°C to 220°C. The above-mentioned fluorination treatment is generally carried out for 1 hour to 30 hours, preferably for 5 hours to 25 hours. The fluorination treatment is preferably a treatment in which the copolymer that has not been fluorinated is contacted with fluorine gas (F2 gas).

[0077] The copolymer of the present invention can also be mixed with other components as needed to obtain a composition. As other components, fillers, plasticizers, processing aids, mold release agents, pigments, flame retardants, lubricants, light stabilizers, weather stabilizers, conductive agents, antistatic agents, ultraviolet absorbers, antioxidants, foaming agents, fragrances, oils, softeners, dehydrofluorination agents, etc. can be cited.

[0078] As fillers, for example, silica, kaolin, clay, organic clay, talc, mica, alumina, calcium carbonate, calcium terephthalate, titanium oxide, calcium phosphate, calcium fluoride, lithium fluoride, crosslinked polystyrene, potassium titanate, carbon, boron nitride, carbon nanotubes, glass fibers, etc. can be cited. As conductive agents, carbon black, etc. can be cited. As plasticizers, dioctyl phthalate, pentaerythritol, etc. can be cited. As processing aids, carnauba wax, sulfone compounds, low molecular weight polyethylene, fluorine-based aids, etc. can be cited. As dehydrofluorination agents, organic oniums, amidines, etc. can be cited.

[0079] As the above other components, other polymers other than the above copolymer can also be used. As other polymers, fluororesins, fluororubbers, non-fluorinated polymers, etc. other than the above copolymer can be cited.

[0080] As the manufacturing method of the above composition, a method of dry-mixing the copolymer with other components; a method of premixing the copolymer with other components using a mixer and then performing melt-kneading using a kneader, a melt extruder, etc. can be cited.

[0081] The copolymer or the above composition of the present invention can be used as a processing aid, a molding material, etc., and is preferably used as a molding material. The aqueous dispersion, solution, suspension, and copolymer / solvent system of the copolymer of the present invention can also be used. They can be coated as a coating, or used for encapsulation, impregnation, and casting of films. However, due to the above characteristics of the copolymer of the present invention, it is preferably used as the above molding material.

[0082] The copolymer or the above composition of the present invention can also be molded to obtain a molded body.

[0083] The method for molding the above copolymer or the above composition is not particularly limited, and examples thereof include injection molding, extrusion molding, compression molding, blow molding, transfer molding, rotational molding, rotational lining molding, etc. Among them, as the molding method, extrusion molding, compression molding, injection molding or transfer molding is preferred, injection molding, extrusion molding or transfer molding is more preferred because a molded article can be produced with high productivity, and injection molding is further preferred. That is, as the molded article, an extruded molded article, a compression molded article, an injection molded article or a transfer molded article is preferred, an injection molded article, an extruded molded article or a transfer molded article is more preferred because it can be produced with high productivity, and an injection molded article is further preferred. By molding the copolymer of the present invention using the injection molding method, an injection molded article having excellent surface smoothness can be obtained with high productivity.

[0084] Examples of the molded article containing the copolymer of the present invention may include nuts, bolts, joints, films, bottles, gaskets, wire coatings, pipes, hoses, ducts, valves, sheets, seals, gaskets, tanks, rolls, containers, cocks, connectors, filter housings, filter covers, flow meters, pumps, wafer carriers, wafer cassettes, etc.

[0085] The copolymer of the present invention, the above composition or the above molded article can be used for the following uses, for example.

[0086] Films for food packaging, lining materials for fluid transfer pipelines used in food manufacturing processes, fluid transfer components for food manufacturing devices such as gaskets, sealing materials, sheets, etc.;

[0087] Plugs for chemical drugs, packaging films, lining materials for fluid transfer pipelines used in chemical drug manufacturing processes, reagent transfer components such as gaskets, sealing materials, sheets, etc.;

[0088] Inner lining components for reagent tanks and pipes in chemical equipment and semiconductor factories;

[0089] O-ring / tube / gasket, spool material, hose, sealing material, etc. used in the fuel system and peripheral devices of automobiles, and fuel transfer components such as hoses and sealing materials used in the AT devices of automobiles;

[0090] Flange gaskets, shaft seals, valve stem seals, sealing materials, hoses, etc. used in carburetors in the engine and peripheral devices of automobiles, and other automobile components such as brake hoses, air conditioning hoses, radiator hoses, wire coating materials, etc. of automobiles;

[0091] O-ring, tube, gasket, spool material, hose, sealing material, roll, gasket, diaphragm, joint, etc. of semiconductor manufacturing devices, and reagent transfer components for semiconductor devices;

[0092] Coating and ink components such as coating rollers, hoses, tubes, ink containers, etc. for coating equipment;

[0093] Tubes, hoses, belts, gaskets, connectors, etc. for food and beverage transportation, such as food and beverage tubes or food and beverage hoses, food packaging materials, glass cooking equipment;

[0094] Waste liquid transfer components such as tubes and hoses for waste liquid transfer;

[0095] High-temperature liquid transfer components such as tubes and hoses for high-temperature liquid transfer;

[0096] Steam piping components such as tubes and hoses for steam piping;

[0097] Anti-corrosion tapes for piping, such as tapes wound around piping on the decks of ships, etc.;

[0098] Various coating materials such as wire coating materials, optical fiber coating materials, transparent surface coating materials provided on the light incident side surface of photovoltaic elements in solar cells, and back agents;

[0099] Sliding components such as diaphragms of diaphragm pumps and various gasket classes;

[0100] Agricultural films, weather-resistant covers such as various roof materials and side walls;

[0101] Interior finishing materials used in the construction field, coating materials for glass such as non-combustible fire safety glass;

[0102] Lining materials such as laminated steel plates used in the home appliance field, etc.

[0103] As fuel transfer components used in the fuel system of the above-mentioned automobile, fuel hoses, filler hoses, evaporator hoses, etc. can be further cited. The above fuel transfer components can also be used as fuel transfer components for acid-resistant gasoline, alcohol-based fuel, fuel with gasoline additives such as methyl tert-butyl ether resistance and amine resistance.

[0104] The above-mentioned chemical medicine stoppers and packaging films have excellent chemical resistance to acids, etc. In addition, as the above-mentioned reagent transfer components, anti-corrosion tapes wound around chemical equipment piping can also be cited.

[0105] As the above-mentioned molded body, radiator water chambers of automobiles, reagent tanks, bellows, partitions, rollers, gasoline tanks, waste liquid transfer containers, high-temperature liquid transfer containers, fishing and fish farming tanks, etc. can also be cited.

[0106] As the above-mentioned molded article, examples further include components used in automotive bumpers, door trim panels, instrument panels, food processing devices, cooking machines, water- and oil-proof glass, lighting-related instruments, indicator panels and housings of OA instruments, electric lighting billboards, display screens, liquid crystal display screens, mobile phones, printer chassis, electrical and electronic components, sundries, trash cans, bathtubs, integrated bathrooms, ventilation fans, lighting frames, and the like.

[0107] The molded article containing the copolymer of the present invention has excellent abrasion resistance at 150°C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation. Therefore, it can be suitably used for nuts, bolts, joints, gaskets, valves, cocks, connectors, filter housings, filter covers, flow meters, pumps, etc. For example, it can be suitably used as a piping component (especially a joint) used in the transportation of reagents and a flow meter housing having a reagent flow path in a flow meter. The piping component and the flow meter housing of the present invention have excellent abrasion resistance at 150°C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation. Therefore, the piping component and the flow meter housing of the present invention can also be suitably used for the flow rate measurement of high-temperature reagents and are not easily damaged even when the reagent is flowing.

[0108] The molded article containing the copolymer of the present invention has excellent abrasion resistance at 150°C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation. Therefore, it can be suitably used as a compressed member such as a washer and a gasket.

[0109] The size and shape of the compressed member of the present invention can be appropriately set according to the use and are not particularly limited. The shape of the compressed member of the present invention can be, for example, a ring shape. In addition, the compressed member of the present invention can have a shape such as a circle, an ellipse, or a quadrangle with rounded corners in a plan view, and has a through hole in the central part thereof.

[0110] The compressed member of the present invention is preferably used as a component for constituting a non-aqueous electrolyte battery. Since the compressed member of the present invention has excellent low electrolyte permeability, it is particularly suitable as a component used in a state of being in contact with the non-aqueous electrolyte in the non-aqueous electrolyte battery. That is, the compressed member of the present invention can have a liquid contact surface with the non-aqueous electrolyte in the non-aqueous electrolyte battery.

[0111] As the non-aqueous electrolyte battery, there is no particular limitation as long as it is a battery having a non-aqueous electrolyte, and examples include a lithium ion secondary battery, a lithium ion capacitor, and the like. In addition, as components constituting the non-aqueous electrolyte battery, there are examples such as a sealing member and an insulating member.

[0112] The above non-aqueous electrolyte is not particularly limited, and one or more of known solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate can be used. The non-aqueous electrolyte battery may further include an electrolyte. The above electrolyte is not particularly limited, and LiClO4, LiAsF6, LiPF6, LiBF4, LiCl, LiBr, CH3SO3Li, CF3SO3Li, cesium carbonate, etc. can be used.

[0113] The compressed member of the present invention can preferably be used as a sealing member such as a sealing washer or a gasket, and an insulating member such as an insulating washer or an insulating gasket. The sealing member is a member used to prevent leakage of liquid or gas or intrusion of liquid or gas from the outside. The insulating member is a member used for electrical insulation. The compressed member of the present invention can also be a member used for both sealing and insulation purposes.

[0114] The compressed member of the present invention has excellent creep resistance and heat resistance deformation after being impregnated with a reagent, so it can be suitably used in a high-temperature environment. For example, the compressed member of the present invention is preferably used in an environment where the maximum temperature is 40°C or higher. For example, the compressed member of the present invention is preferably used in an environment where the maximum temperature is 95°C or higher. Examples of the case where the compressed member of the present invention can reach such a high temperature include, for example, the case where after the compressed member is installed in the battery in a compressed state, other battery components are installed in the battery by welding; the case where the non-aqueous electrolyte battery generates heat; and the like.

[0115] The compressed member of the present invention has excellent creep resistance and heat resistance deformation after being impregnated with a reagent, so it can be suitably used as a sealing member or an insulating member for non-aqueous electrolyte batteries. For example, during charging of a battery such as a non-aqueous electrolyte secondary battery, the temperature of the battery may temporarily reach 40°C or higher, especially temporarily reach 95°C or higher. The compressed member of the present invention can be deformed at a high compression deformation rate at high temperature and used in a non-aqueous electrolyte secondary battery or the like, and further, even when it comes into contact with the non-aqueous electrolyte at high temperature, it will not damage its high resilience. Therefore, when the compressed member of the present invention is used as a sealing member, it has excellent sealing characteristics and can maintain these sealing characteristics for a long time even at high temperature. In addition, since the compressed member of the present invention contains the above copolymer, it has excellent insulating characteristics. Therefore, when the compressed member of the present invention is used as an insulating member, it can be firmly bonded to two or more conductive members to prevent short circuits for a long time.

[0116] The copolymer of the present invention is formed by using an extrusion molding method, so that even when the diameter of the core wire is small, coating breakage will not occur, and a thin coating layer can be formed on the core wire with a small diameter at a high drawing speed, and a coating layer with excellent electrical properties can be formed. Therefore, it can be suitably used as a material for forming an electric wire coating. Therefore, a coated wire having a coating layer containing the copolymer of the present invention has almost no defects such as spark generation even when the diameter of the core wire is small and the coating layer is thin, and the electrical properties are also excellent.

[0117] The coated wire includes a core wire and a coating layer provided around the core wire and containing the copolymer of the present invention. For example, an extrusion molded body obtained by melt-extruding and molding the copolymer of the present invention on the core wire can be used as the coating layer. The coated wire is suitable for LAN cables (Ethernet Cables), high-frequency transmission cables, flat cables, heat-resistant cables, etc., and is particularly suitable for transmission cables such as LAN cables (Ethernet Cables) and high-frequency transmission cables.

[0118] As the material of the core wire, for example, metal conductor materials such as copper and aluminum can be used. The diameter of the core wire is preferably 0.02 mm to 3 mm. The diameter of the core wire is more preferably 0.04 mm or more, further preferably 0.05 mm or more, and particularly preferably 0.1 mm or more. The diameter of the core wire is more preferably 2 mm or less.

[0119] As a specific example of the core wire, for example, AWG (American Wire Gauge)-46 (solid copper wire with a diameter of 40 μm), AWG-26 (solid copper wire with a diameter of 404 μm), AWG-24 (solid copper wire with a diameter of 510 μm), AWG-22 (solid copper wire with a diameter of 635 μm), etc. can be used.

[0120] The thickness of the coating layer is preferably 0.1 mm to 3.0 mm. The thickness of the coating layer is also preferably 2.0 mm or less. By using the above copolymer, a coating layer with a thickness of 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, or 0.2 mm or less can also be formed without problems.

[0121] As a high-frequency transmission cable, a coaxial cable can be cited. A coaxial cable generally has a structure in which an inner conductor, an insulating coating layer, an outer conductor layer, and a protective coating layer are laminated in sequence from the core to the outer periphery. The molded body containing the copolymer of the present invention can be suitably used as the insulating coating layer containing the copolymer. The thickness of each layer in the above structure is not particularly limited. Generally, the diameter of the inner conductor is about 0.1 mm to 3 mm, the thickness of the insulating coating layer is about 0.3 mm to 3 mm, the thickness of the outer conductor layer is about 0.5 mm to 10 mm, and the thickness of the protective coating layer is about 0.5 mm to 2 mm.

[0122] The coating layer may contain air bubbles, and the air bubbles are preferably evenly distributed in the coating layer.

[0123] There is no limitation on the average bubble diameter of the air bubbles. For example, it is preferably 60 μm or less, more preferably 45 μm or less, further preferably 35 μm or less, still further preferably 30 μm or less, particularly preferably 25 μm or less, and especially preferably 23 μm or less. In addition, the average bubble diameter is preferably 0.1 μm or more, more preferably 1 μm or more. The average bubble diameter can be obtained by acquiring an electron microscope image of the wire cross-section and calculating the diameter of each bubble by image processing and then averaging.

[0124] The foaming ratio of the coating layer can be 20% or more. More preferably, it is 30% or more, further preferably 33% or more, still further preferably 35% or more. The upper limit is not particularly limited. For example, it is 80%. The upper limit of the foaming ratio can also be 60%. The foaming ratio is a value obtained by ((specific gravity of the wire coating material - specific gravity of the coating layer) / specific gravity of the wire coating material) × 100. The foaming ratio can be appropriately adjusted according to the use by, for example, adjusting the gas insertion amount in the extruder described later, or by selecting the type of dissolved gas.

[0125] The coated wire may also have other layers between the above-mentioned core wire and the above-mentioned coating layer, and may further have other layers (outer layers) around the coating layer. When the coating layer contains air bubbles, the wire of the present invention may also be a two-layer structure (skin - foam) with a non-foamed layer inserted between the core wire and the coating layer; a two-layer structure (foam - skin) with a non-foamed layer coated on the outer layer; and further a three-layer structure (skin - foam - skin) with a non-foamed layer coated on the outer layer of the skin - foam. The non-foamed layer is not particularly limited and may be a resin layer composed of a TFE / HFP copolymer, a TFE / PAVE copolymer, a TFE / ethylene copolymer, a vinylidene fluoride-based polymer, a polyolefin resin such as polyethylene [PE], a resin such as polyvinyl chloride [PVC], etc.

[0126] The coated wire can be manufactured, for example, by heating a copolymer using an extruder and extruding it onto the core wire in a molten state of the copolymer to form a coating layer.

[0127] When forming the coating layer, it is also possible to heat the copolymer, and in a molten state of the copolymer, introduce a gas into the copolymer to form the above-mentioned coating layer containing air bubbles. As the gas, for example, dichlorofluoromethane, nitrogen, carbon dioxide, or a mixture of the above gases can be used. The gas can be introduced into the heated copolymer in the form of a pressurized gas, or can be generated by mixing a chemical foaming agent in the copolymer. The gas is dissolved in the molten copolymer.

[0128] In addition, the copolymer of the present invention can be suitably used as a material for products for high-frequency signal transmission.

[0129] As the above-mentioned products for high-frequency signal transmission, there is no particular limitation as long as they are products for high-frequency signal transmission. Examples include (1) formed plates such as insulating boards for high-frequency circuits, insulators for connecting components, and printed wiring boards; (2) formed bodies such as bases for high-frequency vacuum tubes and radomes; and (3) coated electric wires such as coaxial cables and LAN cables. The above-mentioned products for high-frequency signal transmission can be suitably used for equipment that utilizes microwaves, particularly microwaves in the range of 3 GHz to 30 GHz, such as satellite communication equipment and mobile phone base stations.

[0130] Among the above-mentioned products for high-frequency signal transmission, the copolymer of the present invention can be suitably used as an insulator in terms of low dielectric loss tangent.

[0131] As the above-mentioned (1) formed plate, from the aspect of obtaining good electrical properties, a printed wiring board is preferred. There is no particular limitation for the above-mentioned printed wiring board, and examples include printed wiring boards for electronic circuits such as mobile phones, various computers, and communication equipment. As the above-mentioned (2) formed body, from the aspect of low dielectric loss, a radome is preferred.

[0132] By molding the copolymer of the present invention by an injection molding method, a sheet with excellent surface smoothness can be obtained with high productivity. In addition, the molded body containing the copolymer of the present invention has excellent abrasion resistance at 150°C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation. Therefore, the molded body containing the copolymer of the present invention can be suitably used as a film or a sheet.

[0133] The film of the present invention is useful as a release film. The release film can be manufactured by molding the copolymer of the present invention by melt extrusion molding, calendering, pressing, casting, etc. From the aspect of obtaining a uniform thin film, the release film can be manufactured by melt extrusion molding.

[0134] The film of the present invention can be applied to the surface of rollers used in OA equipment. In addition, the copolymer of the present invention can be molded into a necessary shape by extrusion molding, compression molding, pressing, etc., and formed into a sheet-like, film-like, or tubular shape for use as a surface material for OA equipment rollers or OA equipment belts. In particular, thin-walled tubes and films can be manufactured by the melt extrusion molding method.

[0135] The molded body containing the copolymer of the present invention has excellent abrasion resistance at 150°C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation, and thus can be suitably used as a bottle or a tube. The bottle or tube of the present invention can easily visually confirm the contents and is not easily damaged during use.

[0136] By molding the copolymer of the present invention using an injection molding method, an injection molded article can be obtained with high productivity. Furthermore, the surface smoothness of the obtained molded article is excellent, and it has excellent abrasion resistance at 150 °C, low carbon dioxide permeability, low reagent permeability, creep resistance, thermal rigidity, and heat resistance to deformation after reagent impregnation. Therefore, it can be suitably used for valves. Accordingly, a valve containing the copolymer of the present invention can be manufactured with high productivity, and is not easily damaged even when repeatedly opened and closed at a high frequency, and has excellent low carbon dioxide permeability and low reagent permeability. In the valve of the present invention, at least the liquid contact portion can be made of the above copolymer. In addition, the valve of the present invention can be a valve having a housing containing the above copolymer.

[0137] The embodiments have been described above, but it is understood that various changes can be made to the embodiments and details without departing from the gist and scope of the claims.

[0138] Examples

[0139] Next, examples are given to illustrate the embodiments of the present invention, but the present invention is not limited to the described examples.

[0140] The respective numerical values in the examples were measured by the following methods.

[0141] (Content of monomer units)

[0142] The content of each monomer unit was measured using an NMR analyzer (for example, AVANCE300 high-temperature probe manufactured by Bruker BioSpin Corporation).

[0143] (Melt flow rate (MFR))

[0144] In accordance with ASTM D1238, using a melt indexer G-01 (manufactured by Toyo Seiki Seisakusho), the mass (g / 10 minutes) of the polymer flowing out from a nozzle having an inner diameter of 2.1 mm and a length of 8 mm every 10 minutes was determined at 372 °C under a load of 5 kg.

[0145] (Number of functional groups)

[0146] The copolymer pellets were cold-pressed to produce a film with a thickness of 0.25 mm to 0.3 mm. This film was scanned 40 times using a Fourier transform infrared spectroscopy analyzer [FT-IR (Spectrum One, manufactured by PerkinElmer)] for analysis to obtain an infrared absorption spectrum, and a differential spectrum from the background spectrum of completely fluorinated and non-functional groups was obtained. The number of functional groups N per 1 × 10 6 carbon atoms in the sample was calculated from the absorption peak of specific functional groups appearing in this differential spectrum according to the following formula (A).

[0147] N = I × K / t (A)

[0148] I: Absorbance

[0149] K: Correction coefficient

[0150] t: Thickness of the film (mm)

[0151] For reference, regarding the functional groups in the present invention, the absorption frequency, molar extinction coefficient, and correction coefficient are shown in Table 2. The molar extinction coefficient is determined from the FT-IR measurement data of low molecular weight model compounds.

[0152] [Table 2]

[0153] Table 2

[0154]

[0155] (Melting point)

[0156] Using a differential scanning calorimeter (trade name: X-DSC7000, manufactured by Hitachi High-Tech Science Corporation), the first heating from 200 °C to 350 °C was carried out at a heating rate of 10 °C / min, then, it was cooled from 350 °C to 200 °C at a cooling rate of 10 °C / min, and the second heating from 200 °C to 350 °C was carried out again at a heating rate of 10 °C / min. The melting point was determined from the peak of the melting curve generated during the second heating process.

[0157] Comparative Example 1

[0158] 51.8 L of pure water was charged into a 174 L autoclave. After sufficient nitrogen replacement, 40.9 kg of perfluorocyclobutane and 2.75 kg of perfluoro(propyl vinyl ether) (PPVE) were charged. The temperature inside the system was maintained at 35 °C and the stirring speed was maintained at 200 rpm. Then, tetrafluoroethylene (TFE) was pressured to 0.64 MPa, and 0.103 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was charged to start the polymerization. Since the pressure inside the system decreased as the polymerization proceeded, TFE was continuously supplied to keep the pressure constant, and 0.058 kg of PPVE was additionally charged for every 1 kg of TFE supplied. When the additional input amount of TFE reached 40.9 kg, the polymerization was terminated. The unreacted TFE was discharged, and after the autoclave was returned to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 43.3 kg of powder.

[0159] The obtained powder was melt-extruded at 360 °C through a screw extruder (trade name: PCM46, manufactured by Ikegai Corporation) to obtain pellets of the TFE / PPVE copolymer. Using the obtained pellets, the PPVE content was measured by the above method.

[0160] The obtained pellets were placed in a vacuum vibration reaction apparatus VVD-30 (manufactured by Okawara Seisakusho Co., Ltd.), and the temperature was raised to 210°C. After evacuating, F2 gas diluted to 20% by volume with N2 gas was introduced to atmospheric pressure. After 0.5 hours from the introduction of the F2 gas, the system was temporarily evacuated, and the F2 gas was introduced again. Furthermore, after 0.5 hours from that time, the system was evacuated again, and the F2 gas was introduced again. Thereafter, the above operations of introducing the F2 gas and evacuating were continuously carried out once within 1 hour, and the reaction was carried out at a temperature of 210°C for 10 hours. After the reaction was completed, the inside of the reactor was thoroughly replaced with N2 gas, and the fluorination reaction was terminated. Using the fluorinated pellets, various physical properties were measured by the above method.

[0161] Comparative Example 2

[0162] 51.8 L of pure water was charged into a 174 L autoclave. After sufficient nitrogen replacement, 40.9 kg of perfluorocyclobutane, 2.05 kg of perfluoro(propyl vinyl ether) (PPVE), and 2.12 kg of methanol were charged. The temperature inside the system was maintained at 35°C and the stirring speed was maintained at 200 rpm. Then, tetrafluoroethylene (TFE) was pressured to 0.64 MPa, and 0.103 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was charged to start the polymerization. Since the pressure inside the system decreased as the polymerization proceeded, TFE was continuously supplied to keep the pressure constant, and 0.046 kg of PPVE was additionally charged for every 1 kg of TFE supplied. When the additional charge amount of TFE reached 40.9 kg, the polymerization was terminated. The unreacted TFE was discharged, and after the inside of the autoclave was restored to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 42.8 kg of powder.

[0163] The obtained powder was melt-extruded at 360°C using a screw extruder (trade name: PCM46, manufactured by Ikegai Corporation) to obtain pellets of the TFE / PPVE copolymer. Using the obtained pellets, the PPVE content was measured by the above method.

[0164] The obtained pellets were placed in a vacuum vibration reaction apparatus VVD-30 (manufactured by Okawara Seisakusho Co., Ltd.), and the temperature was raised to 160°C. After evacuating, F2 gas diluted to 20% by volume with N2 gas was introduced to atmospheric pressure. After 0.5 hours from the introduction of the F2 gas, the system was temporarily evacuated, and the F2 gas was introduced again. Furthermore, after 0.5 hours from that time, the system was evacuated again, and the F2 gas was introduced again. Thereafter, the above operations of introducing the F2 gas and evacuating were continuously carried out once within 1 hour, and the reaction was carried out at a temperature of 160°C for 5 hours. After the reaction was completed, the inside of the reactor was thoroughly replaced with N2 gas, and the fluorination reaction was terminated. Using the fluorinated pellets, various physical properties were measured by the above method.

[0165] Comparative Example 3

[0166] Change PPVE to 1.79 kg, change methanol to 6.61 kg, change the 50% methanol solution of di-n-propyl peroxydicarbonate to 0.051 kg, change PPVE to an additional input of 0.042 kg per 1 kg of TFE supplied, change the heating temperature of the vacuum vibration type reaction device to 210 °C, change the reaction to 10 hours at a temperature of 210 °C, obtain 41.0 kg of dry powder, and obtain fluorinated pellets in the same manner as Comparative Example 2 except for this.

[0167] Comparative Example 4

[0168] Change PPVE to 2.37 kg, change methanol to 1.47 kg, change PPVE to an additional input of 0.052 kg per 1 kg of TFE supplied, change the heating temperature of the vacuum vibration type reaction device to 210 °C, change the reaction to 10 hours at a temperature of 210 °C, obtain 43.0 kg of dry powder, and obtain fluorinated pellets in the same manner as Comparative Example 2 except for this.

[0169] Comparative Example 5

[0170] Change PPVE to 2.43 kg, change methanol to 1.22 kg, change PPVE to an additional input of 0.053 kg per 1 kg of TFE supplied, obtain 43.1 kg of dry powder, and obtain non-fluorinated pellets in the same manner as Comparative Example 2 except for this.

[0171] Comparative Example 6

[0172] Change PPVE to 2.37 kg, change methanol to 2.85 kg, change the 50% methanol solution of di-n-propyl peroxydicarbonate to 0.051 kg, change PPVE to an additional input of 0.052 kg per 1 kg of TFE supplied, change the heating temperature of the vacuum vibration type reaction device to 170 °C, change the reaction to 5 hours at a temperature of 170 °C, obtain 43.0 kg of dry powder, and obtain fluorinated pellets in the same manner as Comparative Example 2 except for this.

[0173] Example 1

[0174] Change PPVE to 2.24 kg, change methanol to 0.83 kg, change PPVE to an additional input of 0.049 kg per 1 kg of TFE supplied, change the heating temperature of the vacuum vibration type reaction device to 180 °C, change the reaction to 10 hours at a temperature of 180 °C, obtain 42.9 kg of dry powder, and obtain fluorinated pellets in the same manner as Comparative Example 2 except for this.

[0175] Example 2

[0176] Change PPVE to 2.37 kg, change methanol to 0.76 kg, change PPVE to an additional input of 0.052 kg per 1 kg of TFE supplied, change the heating temperature of the vacuum vibration reaction device to 210 °C, change the reaction to 10 hours at a temperature of 210 °C, obtain 43.0 kg of dry powder, and otherwise obtain fluorinated pellets in the same manner as in Comparative Example 2.

[0177] Example 3

[0178] Change PPVE to 2.49 kg, change methanol to 0.83 kg, change PPVE to an additional input of 0.054 kg per 1 kg of TFE supplied, change the heating temperature of the vacuum vibration reaction device to 210 °C, change the reaction to 10 hours at a temperature of 210 °C, obtain 43.1 kg of dry powder, and otherwise obtain fluorinated pellets in the same manner as in Comparative Example 2.

[0179] Using the pellets obtained in the examples and comparative examples, various physical properties were measured by the above method. The results are shown in Table 3.

[0180] [Table 3]

[0181] Table 3

[0182]

[0183] The notation "<6" in Table 3 means that the number of functional groups is less than 6.

[0184] Next, using the obtained pellets, the following properties were evaluated. The results are shown in Table 4.

[0185] (Abrasion test)

[0186] Using the pellets and a hot press, a sheet test piece with a thickness of about 0.2 mm was made, and a 10 cm × 10 cm test piece was cut out from it. The fabricated test piece was fixed on the test bench of a Taber abrasion tester (No. 101 special type Taber abrasion tester, manufactured by Yasuda Seiki Seisakusho Co., Ltd.), and an abrasion test was carried out using the Taber abrasion tester under the conditions of a test piece surface temperature of 150 °C, a load of 500 g, an abrasion wheel CS-10 (ground for 20 revolutions with abrasive paper #240), and a rotational speed of 60 rpm. The weight of the test piece after 1000 revolutions was measured, and the weight of the test piece was further measured after 5000 revolutions using the same test piece. The abrasion amount was calculated by the following formula.

[0187] Abrasion amount (mg) = M1 - M2

[0188] M1: Weight of the test piece after 1000 revolutions (mg)

[0189] M2: Weight of the test piece after 5000 revolutions (mg)

[0190] (Carbon dioxide permeability coefficient)

[0191] Using pellets and a hot press, a sheet-like test piece with a thickness of approximately 0.1 mm was produced. Using the obtained test piece, in accordance with the method described in JIS K7126-1:2006, a differential pressure type gas permeation meter (L100-5000 type gas permeation meter, manufactured by Systech illinois) was used to measure the carbon dioxide permeability. The value of the carbon dioxide permeability at a permeation area of 50.24 cm 2 , a test temperature of 70 °C, and a test humidity of 0% RH was obtained. Using the obtained carbon dioxide permeability and the test piece thickness, the carbon dioxide permeability coefficient was calculated by the following formula.

[0192] Carbon dioxide permeability coefficient (cm 3 ·mm / (m 2 ·24h·atm)) = GTR × d

[0193] GTR: Carbon dioxide permeability (cm 3 / (m 2 ·24h·atm))

[0194] d: Test piece thickness (mm)

[0195] (Electrolyte permeability)

[0196] Using pellets and a hot press, a sheet-like test piece with a thickness of approximately 0.2 mm was produced. 10 g of dimethyl carbonate (DMC) was added into a test cup (permeation area 12.56 cm 2 ), covered with the sheet-like test piece, and fastened and sealed with a PTFE gasket clamped. The sheet-like test piece was brought into contact with DMC, taken out after maintaining at 60 °C for 30 days, and the mass reduction was measured after standing at room temperature for 1 hour. The DMC permeability (g·cm / m 2 ) was obtained by the following formula.

[0197] Electrolyte permeability (g·cm / m 2 ) = Mass reduction (g) × Thickness of the sheet-like test piece (cm) / Permeation area (m 2 )

[0198] (Creep resistance evaluation)

[0199] The measurement of creep resistance is based on the methods described in ASTM D395 or JIS K6262:2013. Using pellets and a hot pressing machine, a molded body with an outer diameter of 13 mm and a height of 8 mm is produced. By cutting the obtained molded body, a test piece with an outer diameter of 13 mm and a height of 6 mm is made. The produced test piece is compressed at room temperature to a compression deformation rate of 25% using a compression device. The compressed test piece is left standing in an electric furnace in the state of being fixed to the compression device and placed at 80 °C for 72 hours. The compression device is taken out of the electric furnace, cooled to room temperature, and then the test piece is removed. After the recovered test piece is left standing at room temperature for 30 minutes, the height of the recovered test piece is measured, and the recovery ratio is calculated by the following formula.

[0200] Recovery ratio (%) = (t2 - t1) / t3 × 100

[0201] t1: Height of the spacer (mm)

[0202] t2: Height of the test piece removed from the compression device (mm)

[0203] t3: Height after compression deformation (mm)

[0204] In the above test, t1 = 4.5 mm and t3 = 1.5 mm.

[0205] (Load deflection curvature at 80 °C)

[0206] Using pellets and a hot pressing machine, a sheet-like test piece with a thickness of about 2 mm is produced, and a test piece of 80 × 10 mm is cut out from it and heated in an electric furnace at 100 °C for 20 hours. Except for using the obtained test piece, according to the method described in JIS K-K7191-1, using a heat distortion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the test is carried out under the conditions of a test temperature of 30 °C to 150 °C, a heating rate of 120 °C / hour, a bending stress of 1.8 MPa, and the flatwise method. The load deflection curvature is calculated by the following formula. The sheet with a smaller load deflection curvature at 80 °C has excellent heat rigidity.

[0207] Load deflection curvature (%) = a2 / a1 × 100

[0208] a1: Thickness of the test piece before the test (mm)

[0209] a2: Deflection amount at 80 °C (mm)

[0210] (Reagent immersion crack test (heat resistance to deformation after reagent immersion))

[0211] Using pellets and a hot press molding machine, a sheet with a thickness of about 2 mm was made. Using a rectangular dumbbell of 13.5 mm × 38 mm, the obtained sheet was punched to obtain 3 test pieces. In the center of the long side of each test piece obtained, a 19 mm × 0.45 mm blade was used to cut a notch according to ASTM D1693. Three notched test pieces and 25 g of dimethyl sulfoxide were placed in a 100 mL portable reactor (TVS1 type, made by Pressure Glass Industry Co., Ltd.), and after heating at 150 ° C for 20 hours in an electric furnace, the notched test piece was taken out. The three obtained notched test pieces were installed in a stress crack test fixture according to ASTM D1693, and after heating at 150 ° C for 24 hours in an electric furnace, the notch and its surroundings were visually observed to count the number of cracks. The sheet that does not produce cracks has excellent heat deformation resistance even after being immersed in a reagent.

[0212] ○: The number of cracks is 0

[0213] ×: The number of cracks is 1 or more

[0214] (Injection moldability)

[0215] The copolymer was injection molded using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., SE50EV-A) at a barrel temperature of 390°C, a mold temperature of 170°C, and an injection speed of 50 mm / s. As a mold, a mold (100 mm×100 mm×2.5 mm2) in which HPM38 was plated with Cr was used. The surface of the injection molded body was visually observed, and the surface smoothness was evaluated according to the following criteria.

[0216] 2: The surface is smooth without any roughness.

[0217] 1: Roughness was observed only on the surface of a portion located near the gate of the mold.

[0218] 0: Roughness is observed on most of the surface.

[0219] (Coating disconnection and sparks)

[0220] use The copolymer was extruded onto a copper conductor having a conductor diameter of 0.50 mm using an electric wire coating molding machine (manufactured by TANABE PLASTIC MACHINERY CO., LTD.) at the following coating thickness to obtain a coated electric wire. The electric wire coating extrusion molding conditions were as follows.

[0221] a) Core conductor: conductor diameter 0.50mm

[0222] b) Coating thickness: 0.15mm

[0223] c) Diameter of coated wire: 0.80mm

[0224] d) Wire pulling speed: 150m / min

[0225] e) Extrusion conditions:

[0226] · Single-screw extrusion molding machine with barrel shaft diameter = 30 mm and L / D = 22

[0227] · Die (inner diameter) / sheet (outer diameter) = 8.0 mm / 5.0 mm

[0228] Set temperatures of the extruder: Barrel section C-1 (330 °C), barrel section C-2 (360 °C), barrel section C-3 (375 °C), head H (390 °C), die head D-1 (405 °C), die head D-2 (395 °C). The preheating of the core wire is set at 80 °C.

[0229] (Coating breakage)

[0230] Continuously perform the coating molding of the wire. Consider the situation where the coating breaks more than once within 1 hour as non-continuous molding (×), and the situation where no coating breakage occurs as continuous molding (○).

[0231] (Spark)

[0232] Online set a spark tester (DENSOK HIGH FREQ SPARK TESTER) on the wire coating line, and evaluate the presence or absence of defects in the wire coating at a voltage of 1500 V. Continuously mold for 1 hour. Consider the situation where the spark is zero as qualified (○), and the situation where a spark is detected as unqualified (×).

[0233] (Dielectric loss tangent)

[0234] Melt and mold the pellets to produce a cylindrical test piece with a diameter of 2 mm. Set the produced test piece in a cavity resonator for 6 GHz manufactured by Kanto Electronics Application Development Co., Ltd., and measure it using a network analyzer manufactured by Agilent Technologies, Inc. Analyze the measurement results using the analysis software "CPMA" manufactured by Kanto Electronics Application Development Co., Ltd. on a personal computer connected to the network analyzer, and thus obtain the dielectric loss tangent (tanδ) at 20 °C and 6 GHz.

[0235]

Claims

1. A copolymer containing tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, wherein the content of the perfluoro(propyl vinyl ether) units is 4.6 to 5.2% by mass relative to all monomer units, the monomer units derived from monomers capable of copolymerizing with tetrafluoroethylene and perfluoro(propyl vinyl ether) are 0 to 0.6% by mass or less, the melt flow rate at 372 °C is 22.0 g / 10 min to 28.0 g / 10 min, The number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH is 50 or less relative to every 10 6 main chain carbon atoms, Among them, The copolymer does not include a copolymer containing tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, with the content of perfluoro(propyl vinyl ether) units being 4.6% by mass relative to all monomer units, a melt flow rate at 372 °C of 25.0 g / 10 min, and the number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH being less than 6 per 10 6 main chain carbon atoms.

2. The copolymer according to claim 1, wherein, and the content of the tetrafluoroethylene units is 94.8 to 95.4% by mass relative to all monomer units.

3. An injection molded article containing the copolymer according to claim 1 or 2.

4. A coated wire having a coating layer containing the copolymer according to claim 1 or 2.

5. A molded article, which is a molded article containing the copolymer according to claim 1 or 2, wherein, The molded article is a microtube, a container, a piping member, or a wire coating.

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