Fluorine-containing copolymer

Abstract

Provided is a fluorine-containing copolymer which is a fluorine-containing copolymer containing tetrafluoroethylene units, hexafluoropropylene units, and perfluoro(propyl vinyl ether) units, wherein the content of the hexafluoropropylene units is 7.0 to 8.5 mass% relative to the total monomer units, the content of the perfluoro(propyl vinyl ether) units is 1.5 to 2.9 mass% relative to the total monomer units, and the melt flow rate at 372°C is 9 to 15 g / 10 minutes.

Description

Technical Field

[0001] This invention relates to fluorinated copolymers. Background Technology

[0002] Patent Document 1 describes a terpolymer containing, in copolymer form, (a) tetrafluoroethylene, (b) hexafluoropropylene in a weight of about 4% to about 12% based on the weight of the terpolymer, and (c) perfluoro(ethyl vinyl ether) or perfluoro(n-propyl vinyl ether) in a weight of about 0.5% to about 3% based on the weight of the terpolymer.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 52-109588 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The purpose of this invention is to provide a fluorinated copolymer that can be molded at high injection speed to obtain a beautiful injection molded body, can form a thin coating layer on a small diameter core wire at high speed through extrusion molding, can be molded into a film of uniform thickness through high molding speed through extrusion molding, and can obtain a molded body with excellent wear resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance.

[0008] Methods for solving problems

[0009] According to the present invention, a fluorinated copolymer is provided, which is a fluorinated copolymer containing tetrafluoroethylene units, hexafluoropropylene units and perfluoro(propyl vinyl ether) units, wherein the content of hexafluoropropylene units is 7.0% to 8.5% by mass relative to all monomer units, the content of perfluoro(propyl vinyl ether) units is 1.5% to 2.9% by mass relative to all monomer units, and the melt flow rate at 372°C is 9 g / 10 min to 15 g / 10 min.

[0010] The content of hexafluoropropylene units is preferably 7.2% to 8.1% by mass relative to all monomer units.

[0011] The content of perfluoro(propyl vinyl ether) units is preferably 1.7% to 2.2% by mass relative to all monomer units.

[0012] The melt flow rate at 372℃ is preferably 10 g / 10 min to 14 g / 10 min.

[0013] The optimal number of functional groups is relative to every 106 The main chain has fewer than 90 carbon atoms.

[0014] In addition, according to the present invention, an injection-molded article is provided which contains the above-mentioned fluorinated copolymer.

[0015] In addition, according to the present invention, a coated wire is provided having a coating layer containing the above-mentioned fluorinated copolymer.

[0016] In addition, according to the present invention, a molded body is provided, which is a molded body containing the above-mentioned fluorinated copolymer, wherein the molded body is a valve, connector, flow meter, wire coating or membrane.

[0017] The effects of the invention

[0018] According to the present invention, a fluorinated copolymer can be provided, which can be molded at a high injection speed by injection molding to obtain a beautiful injection molded body, can be formed at a high speed on a core wire with a small diameter by extrusion molding, can be molded into a film of uniform thickness by extrusion molding at a high molding speed, and can obtain a molded body with excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0020] The fluorinated copolymer of the present invention contains tetrafluoroethylene (TFE) units, hexafluoropropylene (HFP) units, and perfluoro(propyl vinyl ether) (PPVE) units.

[0021] As fluoropolymers, non-melt-processable fluoropolymers such as polytetrafluoroethylene (PTFE) and melt-processable fluoropolymers are known. PTFE has excellent properties, but suffers from the disadvantage of being extremely difficult to melt-process. On the other hand, melt-processable fluoropolymers such as TFE / HFP copolymer (FEP) and TFE / PPVE copolymer (PFA) are known, but suffer from disadvantages such as poorer heat resistance compared to PTFE. Therefore, in Patent Document 1, the aforementioned terpolymer was proposed as a fluorocarbon polymer that improves upon these disadvantages.

[0022] However, a fluorinated copolymer is needed that can produce molded bodies with superior moldability, abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and excellent resistance to solvent cracking compared to conventional copolymers. For example, valves used to control the pressure and flow rate of fluids such as pharmaceuticals require high-temperature abrasion resistance, high-temperature rigidity, and tensile creep resistance to prevent damage caused by friction, tensile stress, and loads generated during valve opening and closing. Furthermore, some of these valves have complex structures with thin-walled sections, thus requiring good moldability of the copolymer as well.

[0023] Findings: By adjusting the content of HFP and PPVE units in fluorinated copolymers containing TFE, HFP, and PPVE units, as well as the melt flow rate, to a very limited range, the moldability of fluorinated copolymers is significantly improved, and molded articles with excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance can be obtained.

[0024] Furthermore, by using extrusion molding to form the fluorinated copolymer of the present invention, a thin coating layer can be formed at high speed on a core wire with a small diameter, or a film of uniform thickness can be formed at a high molding speed. Thus, the fluorinated 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 coatings and films.

[0025] The fluorinated copolymer of the present invention is a melt-processable fluoropolymer. Melt processability refers to the ability to melt and process the polymer using existing processing equipment such as extruders and injection molding machines.

[0026] The content of HFP units in the fluorinated copolymer is 7.0% to 8.5% by mass relative to all monomer units, preferably 7.1% by mass or more, more preferably 7.2% by mass or more, even more preferably 7.4% by mass or more, preferably 8.4% by mass or less, more preferably 8.3% by mass or less, even more preferably 8.2% by mass or less, even more preferably 8.1% by mass or less, particularly preferably 7.9% by mass or less, and most preferably 7.7% by mass. If the content of HFP units is too high, it is impossible to obtain a molded article with excellent rigidity at 75°C and excellent tensile creep resistance at 140°C. If the content of HFP units is too low, it is impossible to obtain a molded article with excellent wear resistance and solvent crack resistance at 50°C.

[0027] The content of PPVE units in the fluorinated copolymer is 1.5% to 2.9% by mass relative to all monomer units, preferably 1.6% by mass or more, more preferably 1.7% by mass or more, further preferably 1.8% by mass or more, particularly preferably 1.9% by mass or more, most preferably 2.0% by mass or more, preferably 2.8% by mass or less, more preferably 2.7% by mass or less, further preferably 2.6% by mass or less, even more preferably 2.5% by mass or less, especially more preferably 2.4% by mass or less, particularly preferably 2.3% by mass or less, and most preferably 2.2% by mass or less. By keeping the content of PPVE units in the fluorinated copolymer within the above range, a molded article with excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance can be obtained. If the content of PPVE units is too low, a molded article with excellent abrasion resistance at 50°C and solvent crack resistance cannot be obtained.

[0028] The content of TFE units in the fluorinated copolymer is preferably 88.6% to 91.5% by mass relative to all monomer units, more preferably 88.8% by mass or more, even more preferably 88.9% by mass, even more preferably 89.0% by mass or more, particularly preferably 89.3% by mass or more, most preferably 89.7% by mass or more, more preferably 91.7% by mass or less, even more preferably 91.4% by mass or less, even more preferably 91.3% by mass or less, particularly preferably 91.1% by mass or less, and most preferably 90.8% by mass or less. Alternatively, the content of TFE units can be selected such that the total content of HFP units, PPVE units, TFE units, and other monomer units is 100% by mass.

[0029] The fluorinated copolymer of the present invention only needs to contain the above three monomer units. It can be a copolymer containing only the above three monomer units, or it can be a copolymer containing the above three monomer units and other monomer units.

[0030] As for other monomers, there are no particular limitations as long as they can copolymerize with TFE, HFP, and PPVE. They can be either fluorinated or non-fluorinated monomers.

[0031] As a fluorinated monomer, it is preferably selected from trifluorochloroethylene, vinylidene fluoride, vinylidene fluoride, trifluoroethylene, hexafluoroisobutylene, CH2=CZ. 1 (CF2) n Z 2 (where Z) 1 For H or F, Z 2 The monomer shown is represented by H, F, or Cl, where n is an integer from 1 to 10, CF2 = CF - ORf 1 (where Rf) 1Perfluoro(alkyl vinyl ether) [PAVE] (except for PPVE) represented by perfluoroalkyl groups having 1 to 8 carbon atoms, CF2=CF-O-CH2-Rf 2 (where Rf) 2 It is at least one of the following groups: alkyl perfluorovinyl ether derivatives (represented by a perfluoroalkyl group having 1 to 5 carbon atoms), perfluoro-2,2-dimethyl-1,3-dioxacyclopentene [PDD], and perfluoro-2-methylene-4-methyl-1,3-dioxacyclopentane [PMD].

[0032] As CH2=CZ 1 (CF2) n Z 2 Examples of the monomers shown include CH2=CFCF3, CH2=CH-C4F9, and CH2=CH-C6F. 13 CH2=CF-C3F6H, etc.

[0033] As CF2 = CF - ORf 1 Examples of perfluorinated (alkyl vinyl ethers) include CF2=CF-OCF3 and CF2=CF-OCF2CF3.

[0034] Examples of non-fluorinated monomers include hydrocarbon monomers capable of copolymerizing with TFE, HFP, and PPVE. Examples of hydrocarbon monomers include: olefins such as ethylene, propylene, butene, and isobutylene; alkyl vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, and cyclohexyl vinyl ether; vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl valerate, vinyl pentanoate, vinyl hexanoate, vinyl octanoate, vinyl decanoate, vinyl tert-carbonate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl benzoate, p-tert-butylbenzoate, vinyl cyclohexanecarboxylate, and vinyl monochloroacetate. Vinyl esters such as vinyl adipate, vinyl acrylate, vinyl methacrylate, vinyl crotonate, vinyl sorbate, vinyl cinnamate, vinyl undecenoate, vinyl glycolate, vinyl hydroxypropionate, vinyl hydroxybutyrate, vinyl hydroxyvalerate, vinyl hydroxyisobutyrate, and vinyl hydroxycyclohexanecarboxylate; alkyl allyl ethers such as ethyl allyl ether, propyl allyl ether, butyl allyl ether, isobutyl allyl ether, and cyclohexyl allyl ether; and alkyl allyl esters such as ethyl allyl ester, propyl allyl ester, butyl allyl ester, isobutyl allyl ester, and cyclohexyl allyl ester.

[0035] As non-fluorinated monomers, they can also be hydrocarbon monomers containing functional groups capable of copolymerizing with TFE, HFP, and PPVE. Examples of hydrocarbon monomers containing functional groups include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyisobutyl vinyl ether, and hydroxycyclohexyl vinyl ether; non-fluorinated monomers with glycidyl groups such as glycidyl vinyl ether and glycidyl allyl ether; non-fluorinated monomers with amino groups such as aminoalkyl vinyl ether and aminoalkyl allyl ether; non-fluorinated monomers with amide groups such as (meth)acrylamide and hydroxymethylacrylamide; bromine-containing alkenes, iodine-containing alkenes, bromine-containing vinyl ethers, and iodine-containing vinyl ethers; and non-fluorinated monomers with nitrile groups.

[0036] The content of other monomer units in the fluorinated copolymer of the present invention is preferably 0 to 2.9% by mass relative to all monomer units, more preferably 1.4% by mass or less, even more preferably 1.0% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less.

[0037] The melt flow rate (MFR) of the fluorinated copolymer is 9 g / 10 min to 15 g / 10 min, preferably 9.1 g / 10 min or more, more preferably 9.6 g / 10 min or more, even more preferably 10 g / 10 min or more, particularly preferably 10.8 g / 10 min or more, preferably 14 g / 10 min or less, more preferably 13 g / 10 min or less, and even more preferably 12 g / 10 min or less. By keeping the MFR of the fluorinated copolymer within the above range, the moldability of the copolymer is improved, and molded articles with excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance can be obtained. If the MFR is too low, molded articles with low hydrogen permeability and excellent rigidity at 75°C cannot be obtained; if the MFR is too high, molded articles with excellent abrasion resistance at 50°C, tensile creep resistance at 140°C, and solvent crack resistance cannot be obtained.

[0038] In this invention, the melt flow rate is the value obtained according to ASTM D-1238 using a melt flow index tester G-01 (manufactured by Toyo Seiki Co., Ltd.) as the mass (g / 10 min) of polymer flowing out of a die with an inner diameter of 2 mm and a length of 8 mm every 10 minutes under a load of 5 kg at 372 °C.

[0039] MFR can be adjusted by modifying the type and amount of polymerization initiator and chain transfer agent used during monomer polymerization.

[0040] The fluorinated copolymers of the present invention may or may not have functional groups. Functional groups are those present at the ends of the main chain or side chains of the fluorinated copolymer, or those present in the main chain or side chains. Typical functional groups are -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH.

[0041] 10 of fluorinated copolymers 6 The number of functional groups per carbon atom in the main chain is preferably 90 or less, more preferably 70 or less, even more preferably 50 or less, even more preferably 40 or less, particularly preferably 30 or less, especially preferably 20 or less, and most preferably less than 15. By ensuring that the number of functional groups in the fluorinated copolymer is within the above range, it is possible to obtain a molded article in which fluoride ions are difficult to dissolve in pharmaceutical solutions such as hydrogen peroxide water.

[0042] The number of functional groups in a fluorinated copolymer is the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH.

[0043] 10 of fluorinated copolymers 6 The number of -CF2H atoms per main chain carbon atom is preferably 50 or less, more preferably 40 or less, even more preferably 30 or less, even more preferably 20 or less, particularly preferably less than 15, and most preferably less than 10.

[0044] 10 of fluorinated copolymers 6 The total number of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2 and -CONH2 with a number of carbon atoms in the main chain is preferably 80 or less, more preferably 70 or less, further preferably 50 or less, even more preferably 40 or less, especially preferably 30 or less, particularly preferably 20 or less, and most preferably less than 15.

[0045] The identification of the types of functional groups and the determination of the number of functional groups mentioned above can be achieved using infrared spectroscopy.

[0046] Regarding the number of functional groups, specifically, it was determined using the following method. First, the above-mentioned fluorinated copolymer was cold-pressed to produce a film with a thickness of 0.25 mm to 0.30 mm. The film was analyzed by Fourier transform infrared spectroscopy to obtain the infrared absorption spectrum of the above-mentioned fluorinated copolymer, and a differential spectrum was obtained compared with the background spectrum of a fully fluorinated copolymer without functional groups. The number of functional groups in the above-mentioned fluorinated copolymer was calculated from the absorption peaks of specific functional groups shown in the differential spectrum according to the following formula (A). 6 The number of functional groups N per carbon atom.

[0047] N = I × K / t(A)

[0048] I: Absorbance

[0049] K: Correction coefficient

[0050] t: Membrane thickness (mm)

[0051] For reference, the absorption frequencies, molar absorptivity, and correction factors for some functional groups are shown in Table 1. Furthermore, the molar absorptivity was determined using FT-IR measurements of low-molecular-weight model compounds.

[0052] [Table 1]

[0053] Table 1

[0054]

[0055] The absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are tens of Kaiser (cm⁻¹) lower than those of -CF2H, -COF, free -COOH, and bonded -COOH, -COOCH3, and -CONH2, respectively, as shown in the table. 1 ).

[0056] For example, the number of functional groups in -COF refers to the number of functional groups originating from the absorption frequency of -CF2COF at 1883 cm⁻¹. 1 The number of functional groups derived from the absorption peak at 1840 cm⁻¹ and the absorption frequency originating from -CH₂COF were also analyzed. 1 The total number of functional groups obtained from the absorption peak at the given location.

[0057] Alternatively, the number of -CF2H groups can also be determined using a nuclear magnetic resonance (NMR) apparatus, with the measurement temperature set to (the polymer's melting point + 20) °C. 19 The value was determined by F-NMR analysis and obtained from the peak integral of the -CF2H group.

[0058] Functional groups are those present at the ends of the main chain or side chains of fluorinated copolymers, 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.

[0059] The aforementioned functional groups are introduced into the fluorinated copolymer, for example, through chain transfer agents or polymerization initiators used in the manufacture of the fluorinated copolymer. For instance, when an alcohol is used as a chain transfer agent, or when a peroxide having a -CH2OH structure is used as a polymerization initiator, -CH2OH is introduced to the ends of the main chain of the fluorinated copolymer. Alternatively, the aforementioned functional groups are introduced to the ends of the side chains of the fluorinated copolymer by polymerizing monomers containing functional groups.

[0060] By subjecting the fluorinated copolymer having such functional groups to wet heat treatment, fluorination treatment, or other treatments, a fluorinated copolymer having the number of functional groups within the aforementioned range can be obtained. The fluorinated copolymer of the present invention preferably underwent wet heat treatment or fluorination treatment, and more preferably fluorination treatment. The fluorinated copolymer of the present invention also preferably has a -CF3 terminal group.

[0061] The melting point of the fluorinated copolymer is preferably 250°C to 285°C, more preferably 260°C to 272°C. By keeping the melting point within the above range, the moldability of the copolymer is further improved, and molded articles with better abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance can be obtained.

[0062] In this invention, the melting point can be determined using a differential scanning calorimeter (DSC).

[0063] The hydrogen permeability coefficient of the fluorinated copolymer is preferably 1790 cm⁻¹. 3 ·mm / (m 2 The hydrogen permeability is below 24 h atm. The fluorinated copolymer of the present invention exhibits excellent low hydrogen permeability due to the appropriate adjustment of the content of HFP and PPVE units and the melt flow rate. Therefore, for example, containers obtained using the fluorinated copolymer of the present invention can be appropriately used to store pharmaceutical solutions for which it is undesirable to allow hydrogen from external gases to mix in.

[0064] In this invention, the hydrogen permeability coefficient can be determined under test conditions of 60°C and 0% RH. The specific determination of the hydrogen permeability coefficient can be performed using the methods described in the examples.

[0065] The amount of fluoride ions dissolved by the fluorine-containing copolymer of the present invention in the immersion test in hydrogen peroxide water is preferably 4.0 ppm or less by mass, more preferably 3.0 ppm or less, and even more preferably 2.8 ppm or less.

[0066] In this invention, the immersion test in hydrogen peroxide water can be carried out as follows: using a fluorinated copolymer, a test piece with a weight equivalent to 10 molded pieces (15mm×15mm×0.2mm) is prepared. A polypropylene bottle containing the test piece and 15g of 3% hydrogen peroxide aqueous solution is placed in a constant temperature bath at 95°C and left for 20 hours.

[0067] The fluorinated copolymers of the present invention can be manufactured by any of the polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. In these polymerization methods, the conditions such as temperature and pressure, the polymerization initiator, chain transfer agent, solvent, and other additives can be appropriately set according to the desired composition and amount of the fluorinated copolymer.

[0068] Oil-soluble free radical polymerization initiators or water-soluble free radical initiators can be used as polymerization initiators.

[0069] As an oil-soluble free radical polymerization initiator, it can be a known oil-soluble peroxide, and the following substances can be cited as representative examples:

[0070] Dialkyl percarbonate esters, such as di-n-propyl percarbonate, diisopropyl percarbonate, and disec-butyl percarbonate;

[0071] Peroxide esters such as tert-butyl peroxide isobutyrate and tert-butyl perpentyl peroxide;

[0072] Dialkyl peroxides such as di-tert-butyl peroxide;

[0073] Di[fluoro(or fluorochloro)acyl] peroxides; etc.

[0074] Examples of diacyl peroxides include those represented by [(RfCOO)-]2 (where Rf is a perfluoroalkyl, ω-hydroperfluoroalkyl, or fluorochloroalkyl).

[0075] Examples of di[fluoro(or fluorochloro)acyl]peroxides include, for example, di(ω-hydro-dodecanoyl)peroxide, di(ω-hydro-tetradecanoyl)peroxide, di(ω-hydro-hexadecanoyl)peroxide, di(perfluorobutyryl)peroxide, di(perfluoropentanoyl)peroxide, di(perfluorohexanoyl)peroxide, di(perfluoroheptanoyl)peroxide, di(perfluorooctanoyl)peroxide, di(perfluorononanoyl)peroxide, di(ω-chloro-hexafluorobutyryl)peroxide, di(ω-chloro-decanoyl)peroxide, and di(ω-decanoyl)peroxide. Fluorohexyl peroxide, di(ω-chloro-tetrafluorooctanoyl) peroxide, ω-hydro-dodecanoyl-ω-hydrohexadecanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydro-dodecanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutyryl) peroxide, di(trichlorooctafluorohexanoyl) peroxide, di(tetrachloroundecanoyl) peroxide, di(pentachlorotetrafluorodecanoyl) peroxide, di(undecatrifluorotetrafluorodienoyl) peroxide, etc.

[0076] As a water-soluble free radical polymerization initiator, it can be a known water-soluble peroxide, such as ammonium salts, potassium salts, sodium salts of persulfate, perboric acid, perchloric acid, superphosphoric acid, and percarbonate, as well as tert-butyl maleate peroxide and tert-butyl hydroperoxide. It may also contain reducing agents such as sulfites, in amounts ranging from 0.1 to 20 times that of the peroxide.

[0077] Examples of chain transfer agents include hydrocarbons such as ethane, isopentane, n-hexane, and cyclohexane; aromatics such as toluene and xylene; ketones such as acetone; acetates such as ethyl acetate and butyl acetate; alcohols such as methanol, ethanol, and 2,2,2-trifluoroethanol; thiols such as methyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, chloroform, dichloromethane, and chloromethane; and 3-fluorobenzotrifluoride. The amount added varies depending on the chain transfer constant of the compound used, and is typically used in the range of 0.01 to 20 parts by mass relative to 100 parts by mass of solvent.

[0078] For example, when using dialkyl peroxide carbonates, di[fluoro(or fluorochloro)acyl]peroxides, etc., as polymerization initiators, the resulting fluorinated copolymers have excessively high molecular weights, sometimes making it difficult to adjust to the desired melt flow rate. However, chain transfer agents can be used to adjust the molecular weight. Fluorinated copolymers are particularly preferably manufactured by suspension polymerization using chain transfer agents such as alcohols and oil-soluble free radical polymerization initiators.

[0079] Examples of solvents include water and mixtures of water and alcohol. Alternatively, the monomers used in the polymerization of the fluorinated copolymers of this invention can also be used as solvents.

[0080] In suspension polymerization, fluorinated solvents can be used in addition to water. Examples of fluorinated solvents include hydrochlorofluorocarbons such as CH3CClF2, CH3CCl2F, CF3CF2CCl2H, and CF2ClCF2CFHCl; chlorofluorocarbons such as CF2ClCFClCF2CF3 and CF3CFClCFClCF3; and perfluoroalkyl hydrocarbons such as perfluorocyclobutane, CF3CF2CF2CF3, CF3CF2CF2CF2CF3, and CF3CF2CF2CF2CF2CF3, with perfluoroalkyl hydrocarbons being preferred. From the perspectives of suspension performance and economy, the amount of fluorinated solvent used is preferably 10 to 100 parts by mass relative to 100 parts by mass of the solvent.

[0081] There is no particular limitation on the polymerization temperature, which can be 0 to 100°C. However, if the decomposition rate of the polymerization initiator is too fast, such as when using dialkyl peroxide carbonate, di[fluoro(or fluorochloro)acyl]peroxide, etc., as the polymerization initiator, it is preferable to use a lower polymerization temperature, such as a polymerization temperature range of 0°C to 35°C.

[0082] The polymerization pressure is appropriately determined based on the type and amount of solvent used, vapor pressure, polymerization temperature, and other polymerization conditions, and is typically 0–9.8 MPaG. The polymerization pressure is preferably 0.1 MPaG–5 MPaG, more preferably 0.5 MPaG–2 MPaG, and even more preferably 0.5 MPaG–1.5 MPaG. Furthermore, a polymerization pressure of 1.5 MPaG or higher can improve production efficiency.

[0083] Examples of additives used in polymerization include suspension stabilizers. There are no particular limitations on existing, well-known suspension stabilizers; methylcellulose, polyvinyl alcohol, etc., can be used. When a suspension stabilizer is used, the suspended particles generated by the polymerization reaction are stably dispersed in the aqueous medium. Therefore, even when using a SUS-made reaction tank without anti-adhesion treatment such as a glass liner, the suspended particles are less likely to adhere to the reaction tank. This allows the use of a high-pressure-resistant reaction tank, enabling polymerization under high pressure and improving production efficiency. Conversely, if polymerization is carried out without a suspension stabilizer, and a SUS-made reaction tank without anti-adhesion treatment is used, suspended particles may adhere, reducing production efficiency. The concentration of the suspension stabilizer relative to the aqueous medium can be adjusted appropriately according to the conditions.

[0084] When an aqueous dispersion containing a fluoropolymer is obtained through polymerization, the dried fluoropolymer can be recovered by precipitating, washing, and drying the fluoropolymer contained in the aqueous dispersion. Alternatively, when a fluoropolymer is obtained in slurry form through polymerization, the dried fluoropolymer can be recovered by removing the slurry from the reaction vessel and washing and drying it. Drying allows the fluoropolymer to be recovered in powder form.

[0085] Fluorinated copolymers obtained through polymerization can be granulated. There are no particular limitations on the granulation method; existing known methods can be used. For example, methods such as melt extruding the fluorinated copolymer using a single-screw extruder, twin-screw extruder, or tandem extruder, and then cutting it into granules of a specified length, can be used. The extrusion temperature during melt extrusion needs to be varied depending on the melt viscosity of the fluorinated copolymer and the manufacturing method; preferably, it is between the melting point of the fluorinated copolymer and 20°C to 140°C. There are no particular limitations on the cutting method of the fluorinated copolymer; existing known methods such as wire cutting, thermal cutting, underwater cutting, and sheet cutting can be used. The volatile components in the granules can also be removed by heating (degassing treatment). Alternatively, the granules can 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.

[0086] Fluorinated copolymers obtained through polymerization can also be heated to temperatures above 100°C in the presence of air and water (wetting heat treatment). Examples of wetting heat treatment methods include: using an extruder, supplying air and water while melting and extruding the fluorinated copolymer obtained through polymerization. Wetting heat treatment can convert thermally unstable functional groups such as -COF and -COOH in the fluorinated copolymer into the more thermally stable -CF2H, easily adjusting the total number of -COF and -COOH, as well as the total number of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, and -CONH2 in the fluorinated copolymer to the ranges described above. Besides air and water, heating the fluorinated copolymer in the presence of alkali metal salts can promote the conversion reaction to -CF2H. However, it should be noted that contamination from alkali metal salts should be avoided depending on the intended use of the fluorinated copolymer.

[0087] Fluorinated copolymers obtained by polymerization can also be fluorinated. Fluorination can be carried out by contacting the unfluorinated copolymer with a fluorinated compound. Through fluorination, thermally unstable functional groups such as -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, and -CONH2, as well as thermally stable functional groups such as -CF2H, in the fluorinated copolymer can be converted into the extremely thermally stable -CF3. As a result, the total number of COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, and -CF2H groups in the fluorinated copolymer can be easily adjusted to the range described above.

[0088] As for fluorine-containing compounds, there are no particular limitations; any fluorine radical source that generates fluorine radicals under fluorination conditions can be cited. Examples of such fluorine radical sources include F2 gas, CoF3, AgF2, UF6, OF2, N2F2, CF3OF, and fluorinated halogens (e.g., IF5, ClF3).

[0089] Fluorine radical sources such as F2 gas can be 100% concentrated, but from a safety perspective, it is preferable to mix them with an inert gas and dilute them to 5% to 50% by mass before use, and more preferably to 15% to 30% by mass. Examples of such inert gases include nitrogen, helium, and argon; from an economic perspective, nitrogen is preferred.

[0090] The conditions for fluorination are not particularly limited; the molten fluorinated copolymer can be brought into contact with the fluorinated compound. However, it is generally carried out at a temperature below the melting point of the fluorinated copolymer, preferably between 20°C and 220°C, and more preferably between 100°C and 200°C. The fluorination treatment is typically carried out for 1 hour to 30 hours, preferably 5 hours to 25 hours. The preferred method of fluorination treatment is to bring the unfluorinated fluorinated copolymer into contact with fluorine gas (F2 gas).

[0091] The fluorinated copolymer of the present invention can also be mixed with other components as needed to obtain a composition. Other components include 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, defluorinated hydrogen agents, etc.

[0092] Examples of fillers include silica, kaolin, clay, organoclay, talc, mica, alumina, calcium carbonate, calcium terephthalate, titanium dioxide, calcium phosphate, calcium fluoride, lithium fluoride, cross-linked polystyrene, potassium titanate, carbon, boron nitride, carbon nanotubes, and glass fiber. Examples of conductive agents include carbon black. Examples of plasticizers include dioctyl phthalate and pentaerythritol. Examples of processing aids include carnauba wax, sulfone compounds, low molecular weight polyethylene, and fluorinated additives. Examples of defluorinating agents include organonium and amidines.

[0093] In addition, other polymers besides the fluorinated copolymers mentioned above can also be used as other components. Examples of other polymers include fluoropolymers, fluororubbers, and non-fluorinated polymers, in addition to the fluorinated copolymers mentioned above.

[0094] Examples of methods for manufacturing the above composition include: dry mixing of the fluorinated copolymer with other components; pre-mixing the fluorinated copolymer with other components using a mixer, followed by melt mixing using a kneader, melt extruder, etc.; etc.

[0095] The fluorinated copolymers or the above-described compositions of the present invention can be used as processing aids, molding materials, etc., and are preferably used as molding materials. Additionally, aqueous dispersions, solutions, suspensions, and copolymer / solvent systems of the fluorinated copolymers of the present invention can be used as coatings, or for encapsulation, impregnation, and film casting. However, due to the aforementioned properties, the fluorinated copolymers of the present invention are preferably used as the above-described molding materials.

[0096] The fluorinated copolymer of the present invention or the above composition can also be molded to obtain a molded body.

[0097] The method for molding the above-mentioned fluorinated copolymer or composition is not particularly limited, and examples include injection molding, extrusion molding, compression molding, blow molding, transfer molding, rotational molding, and roll forming. Among these molding methods, extrusion molding, compression molding, injection molding, or transfer molding are preferred, and injection molding, extrusion molding, or transfer molding are more preferred because they can produce molded articles with high productivity; injection molding is even more 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, and injection molded articles, extrusion molded articles, or transfer molded articles are more preferred because they can be produced with high productivity; injection molded articles are even more preferred. By using injection molding to mold the fluorinated copolymer of the present invention, even when molding at high injection speeds, a beautiful molded article can be obtained.

[0098] As molded bodies containing the fluorinated copolymer of the present invention, they can be, for example, nuts, bolts, joints, membranes, bottles, washers, wire sheaths, tubes, hoses, pipes, valves, plates, seals, gaskets, cans, rollers, containers, stopcocks, connectors, filter housings, filter covers, flow meters, pumps, wafer carriers, wafer boxes, etc.

[0099] The fluorinated copolymers, the above-described compositions, or the above-described molded articles of the present invention can be used for, for example, the following applications.

[0100] Food packaging films, lining materials for fluid transport pipelines used in food manufacturing processes, gaskets, sealing materials, thin sheets, and other fluid transport components for food manufacturing equipment;

[0101] Chemical stoppers, packaging films, lining materials for fluid delivery pipelines used in chemical manufacturing processes, gaskets, sealing materials, thin plates, and other reagent delivery components;

[0102] Inner lining components for chemical equipment and semiconductor plants' liquid tanks and piping;

[0103] O-rings / pipes / gaskets, valve core materials, hoses, sealing materials, etc. used in the fuel system and peripheral devices of automobiles; hoses, sealing materials, and other fuel delivery components used in the AT system of automobiles.

[0104] The carburetor flange gaskets, shaft seals, valve stem seals, sealing materials, hoses, etc. used in the engine and peripheral devices of automobiles; brake hoses, air conditioning hoses, radiator hoses, wire sheathing materials, and other automobile components.

[0105] O-rings, tubes, gaskets, valve core materials, hoses, sealing materials, rollers, washers, diaphragms, connectors and other chemical delivery components for semiconductor manufacturing equipment;

[0106] Coating and ink components for coating equipment, such as coating rollers, hoses, tubes, and ink containers;

[0107] Food and beverage conduits, hoses, belts, gaskets, connectors and other food and beverage conveying components, food packaging materials, and glass cooking equipment;

[0108] Pipes, hoses, and other components used for waste liquid transportation;

[0109] Pipes, hoses, and other components used for high-temperature liquid transfer;

[0110] Pipes, hoses and other components used in steam piping;

[0111] Corrosion-resistant tape for piping, such as tape wrapped around the deck of a ship;

[0112] Various coating materials, such as wire coating materials, optical fiber coating materials, transparent surface coating materials and backing agents applied to the light incident side of photovoltaic elements in solar cells;

[0113] The diaphragm and various sliding components such as gaskets in a diaphragm pump;

[0114] Weather-resistant covers for agricultural films, various roofing materials, and sidewalls;

[0115] Interior materials used in the construction industry, and glass-like covering materials such as non-combustible fire-resistant safety glass;

[0116] Lining materials such as laminated steel sheets used in the home appliance industry.

[0117] Further examples of fuel delivery components used in the fuel systems of the aforementioned automobiles include fuel hoses, filler hoses, and evaporator hoses. These fuel delivery components can also be used for fuels resistant to acidic gasoline, alcohol-based fuels, and fuels containing gasoline additives such as those resistant to methyl tert-butyl ether and amines.

[0118] The aforementioned chemical stoppers and packaging films exhibit excellent chemical resistance to acids and other chemicals. Additionally, anti-corrosion tape wrapped around the piping of chemical equipment can also be cited as a component for transporting the aforementioned chemical solutions.

[0119] Examples of the aforementioned molded bodies include automobile radiator water chambers, medicine tanks, bellows, partitions, rollers, gasoline tanks, waste liquid conveying containers, high-temperature liquid conveying containers, and fish farming and aquaculture tanks.

[0120] Further examples of the molded bodies mentioned above include components used in automobile bumpers, door panels, dashboards, food processing devices, cooking machines, waterproof and oil-proof glass, lighting-related instruments, indicator panels and housings of OA instruments, electrically illuminated signboards, displays, LCD screens, mobile phones, printer chassis, electrical and electronic components, groceries, trash cans, bathtubs, prefabricated bathrooms, exhaust fans, lighting frames, etc.

[0121] The molded articles containing the fluorinated copolymer of the present invention exhibit excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance. Therefore, they are suitable for use in nuts, bolts, joints, gaskets, valves, stopcocks, connectors, filter housings, filter covers, flow meters, pumps, etc. They are particularly suitable for use as piping components (especially valves and joints) in pharmaceutical liquid transportation, and as flow meter bodies that incorporate a flow path for pharmaceutical liquid. The piping components and flow meter bodies of the present invention exhibit excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance. Therefore, the piping components and flow meter bodies of the present invention are not easily worn or deformed even when subjected to loads due to the start, stop, or flow rate changes of the pharmaceutical liquid.

[0122] Molded articles containing the fluorinated copolymer of the present invention can be obtained by injection molding at high injection speed to produce beautiful injection molded articles. They exhibit excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance, making them suitable for use as gaskets, seals, and other compressed components. The compressed components of the present invention can be gaskets or seals. The gaskets or seals of the present invention can be manufactured at low cost by injection molding, exhibiting excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance.

[0123] The size and shape of the compressed member of the present invention can be appropriately set according to the application and are not particularly limited. The shape of the compressed member of the present invention can be, for example, ring-shaped. In addition, the compressed member of the present invention can have a circular, elliptical, or quadrilateral shape with rounded corners when viewed from above, and has a through hole in its central part.

[0124] The compressed member of the present invention is preferably used as a component for constructing a non-aqueous electrolyte battery. The compressed member of the present invention is not easily damaged even under repeated stress and has excellent sealing properties, making it particularly suitable as a component for use in contact with the non-aqueous electrolyte in a non-aqueous electrolyte battery. That is, the compressed member of the present invention can have a liquid-contacting surface for contact with the non-aqueous electrolyte in a non-aqueous electrolyte battery.

[0125] As for non-aqueous electrolyte batteries, there are no particular limitations as long as the battery contains a non-aqueous electrolyte; examples include lithium-ion secondary batteries and lithium-ion capacitors. Furthermore, components constituting non-aqueous electrolyte batteries include sealing components and insulating components.

[0126] The non-aqueous electrolyte is not particularly limited and can be one or more of the following known solvents: propylene carbonate, ethylene carbonate, butyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate. The non-aqueous electrolyte battery may further include an electrolyte. The electrolyte is not particularly limited and can be LiClO4, LiAsF6, LiPF6, LiBF4, LiCl, LiBr, CH3SO3Li, CF3SO3Li, cesium carbonate, etc.

[0127] The compressed component of the present invention can preferably be used as a sealing component such as a sealing gasket or sealing pad, or an insulating component such as an insulating gasket or insulating pad. A sealing component is used to prevent leakage of liquid or gas or intrusion of liquid or gas from the outside. An insulating component is used for electrical insulation. The compressed component of the present invention can also be used for both sealing and insulation purposes.

[0128] The compressed component of the present invention is not easily damaged even under repeated stress and exhibits excellent sealing performance, thus making it suitable for use as a sealing component or insulating component for non-aqueous electrolyte batteries. Furthermore, the compressed component of the present invention, containing the aforementioned fluorinated copolymer, possesses excellent insulating properties. Therefore, when the compressed component of the present invention is used as an insulating component, it securely seals with two or more conductive components, preventing short circuits over a long period.

[0129] The fluorinated copolymer of the present invention can be formed into a thin coating layer at high speed on a small-diameter core wire by extrusion molding, thus making it suitable as a material for forming wire coatings. Wires with a coating layer containing the fluorinated copolymer of the present invention exhibit almost no spark defects and therefore excellent electrical properties.

[0130] The coated wire has a core wire and a coating layer disposed around the core wire containing the fluorinated copolymer of the present invention. For example, the coating layer can be an extruded body formed by melt extrusion molding of the fluorinated copolymer of the present invention onto the core wire. 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.

[0131] The core wire material can be a metallic conductor such as copper or aluminum. The core wire diameter is preferably 0.02 mm to 3 mm. More preferably, the core wire diameter is 0.04 mm or more, even more preferably 0.05 mm or more, and particularly preferably 0.1 mm or more. Even more preferably, the core wire diameter is 2 mm or less.

[0132] Specific examples of core wires include AWG (American wire gauge)-46 (solid copper wire with a diameter of 40μm), AWG-26 (solid copper wire with a diameter of 404μm), AWG-24 (solid copper wire with a diameter of 510μm), and AWG-22 (solid copper wire with a diameter of 635μm).

[0133] The thickness of the coating layer is preferably 0.1 mm to 3.0 mm. The thickness of the coating layer is also preferably less than 2.0 mm.

[0134] Coaxial cables are an example of high-frequency transmission cables. Coaxial cables typically have a structure consisting of an inner conductor, an insulating sheath, an outer conductor layer, and a protective sheath layer layered sequentially from the core to the outer periphery. Molded bodies containing the fluorinated copolymer of the present invention can be suitable as insulating sheaths containing the fluorinated copolymer. The thickness of each layer in the above structure is not particularly limited; typically, the diameter of the inner conductor is about 0.1 mm to 3 mm, the thickness of the insulating sheath 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 sheath is about 0.5 mm to 2 mm.

[0135] The coating may contain air bubbles, which are preferably evenly distributed in the coating.

[0136] The average bubble diameter is not limited, but is preferably 60 μm or less, more preferably 45 μm or less, even more preferably 35 μm or less, even more preferably 30 μm or less, particularly preferably 25 μm or less, and especially preferably 23 μm or less. Furthermore, 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, calculating the diameter of each bubble using image processing, and then averaging the results.

[0137] The foaming rate of the coating layer can be 20% or more. More preferably, it is 30% or more, further preferably 33% or more, and even more preferably 35% or more. There is no particular upper limit, for example, 80%. The upper limit of the foaming rate can be 60%. The foaming rate is calculated as ((specific gravity of wire coating material - specific gravity of coating layer) / specific gravity of wire coating material) × 100. The foaming rate can be adjusted appropriately according to the application, for example, by adjusting the gas insertion amount in the extruder described later, or by selecting the type of dissolved gas.

[0138] The coated wire may also have other layers between the core wire and the coating layer, and may further have other layers (outer layers) around the coating layer. If the coating layer contains air bubbles, the wire of the present invention may also be a two-layer structure (outer sheath-foam) with a non-foamed layer inserted between the core wire and the coating layer; a two-layer structure (foam-outer sheath) with a non-foamed layer on the outer layer; and a three-layer structure (outer sheath-foam-outer sheath) with a non-foamed layer on the outer layer of the outer sheath-foam. The non-foamed layer is not particularly limited and may be a resin layer composed of TFE / HFP copolymers, TFE / PAVE copolymers, TFE / ethylene copolymers, vinylidene fluoride polymers, polyolefin resins such as polyethylene [PE], and resins such as polyvinyl chloride [PVC].

[0139] Coated wires can be manufactured, for example, by heating a fluorinated copolymer using an extruder and extruding it onto the core wire while the fluorinated copolymer is in a molten state to form a coating.

[0140] During the formation of the coating layer, the fluorinated copolymer can also be heated, and a gas can be introduced into the fluorinated copolymer while it is in a molten state to form the aforementioned coating layer containing bubbles. The gas can be, for example, dichlorofluoromethane, nitrogen, carbon dioxide, or a mixture of these gases. The gas can be introduced into the heated fluorinated copolymer as a pressurized gas, or it can be generated by mixing a chemical foaming agent into the fluorinated copolymer. The gas dissolves in the molten fluorinated copolymer.

[0141] In addition, the fluorinated copolymer of the present invention is suitable for use as a material in products for high-frequency signal transmission.

[0142] As for the aforementioned high-frequency signal transmission products, there are no particular limitations as long as the product is used for high-frequency signal transmission. Examples include (1) molded boards such as insulating boards for high-frequency circuits, insulating materials for connecting components, and printed wiring boards; (2) molded bodies such as bases and radomes for high-frequency vacuum tubes; and (3) covered wires such as coaxial cables and LAN cables. The aforementioned high-frequency signal transmission products are suitable for use in satellite communication equipment, mobile phone base stations, and other equipment that utilizes microwaves, especially microwaves from 3 GHz to 30 GHz.

[0143] In the aforementioned high-frequency signal transmission products, the fluorinated copolymer of the present invention is suitable for use as an insulator due to its low dielectric loss tangent.

[0144] As for the molded plate described in (1) above, a printed wiring substrate is preferred from the perspective of obtaining good electrical characteristics. There are no particular limitations on the printed wiring substrate described above; examples include printed wiring substrates for electronic circuits in mobile phones, various computers, and communication devices. As for the molded body described in (2) above, an antenna radome is preferred from the perspective of low dielectric loss.

[0145] The fluorinated copolymer of the present invention can be formed into a film of uniform thickness at a high forming speed by extrusion molding. As a result, the obtained molded body has excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance, and is therefore suitable for use in films.

[0146] The film of the present invention is useful as a release film. The release film can be manufactured by molding the fluorinated copolymer of the present invention through melt extrusion molding, calendering, compression molding, casting, etc. From the viewpoint of obtaining a uniform film, the release film can be manufactured by melt extrusion molding.

[0147] The membrane of this invention can be applied to the surface of rollers used in OA equipment. Furthermore, the fluorinated copolymer of this invention can be molded into necessary shapes, such as sheets, films, or tubes, through extrusion molding, compression molding, or pressing, for use as a surface material for OA equipment rollers or belts. In particular, thin-walled tubes and membranes can be manufactured using melt extrusion molding.

[0148] The fluorinated copolymer of the present invention can be injection molded at high injection speed to obtain beautiful injection molded articles. Furthermore, the resulting molded articles exhibit excellent abrasion resistance at 50°C, low hydrogen permeability, rigidity at 75°C, tensile creep resistance at 140°C, and solvent crack resistance, making them suitable for use in valves. Therefore, valves containing the fluorinated copolymer of the present invention can be manufactured at low cost and high productivity, and are not easily damaged even with frequent opening and closing, exhibiting excellent sealing performance. At least the liquid-contact portion of the valve of the present invention can be composed of the aforementioned fluorinated copolymer. Additionally, the valve of the present invention can be a valve having a shell containing the aforementioned fluorinated copolymer.

[0149] The embodiments have been described above, but it is understood that various changes can be made to the methods and details without departing from the spirit and scope of the claims.

[0150] Example

[0151] Next, embodiments will be given to illustrate the implementation of the present invention, but the present invention is not limited to the embodiments described.

[0152] The values ​​in the examples were measured using the following methods.

[0153] (Monomer content)

[0154] The content of each monomer unit in the fluorinated copolymer was determined using an NMR analyzer (e.g., Bruker BioSpin, AVANCE300 high-temperature probe) or an infrared absorption analyzer (Perkin Elmer, Spectrum One).

[0155] (Quantity of -CF2H)

[0156] The number of -CF2H groups in the fluorinated copolymer was determined using an AVANCE-300 nuclear magnetic resonance (NMR) system (manufactured by Bruker BioSpin) at a temperature set to (polymer melting point + 20) °C. 19 The value was determined by F-NMR analysis and obtained from the peak integral of the -CF2H group.

[0157] (The number of -COOH-COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2)

[0158] The dried powders or granules obtained in the examples and comparative examples were cold-pressed to form films with a thickness of 0.25 mm to 0.3 mm. The films were analyzed by scanning them 40 times using a Fourier transform infrared spectroscopy (FT-IR) device (Spectrum One, PerkinElmer) to obtain infrared absorption spectra. The obtained infrared absorption spectra were compared with those of known films to determine the types of terminal groups. Furthermore, based on the absorption peaks of specific functional groups appearing in the differential spectrum between the obtained infrared absorption spectra and those of known films, the concentration of each 1 × 10⁻⁶ functional group in the sample was calculated according to the following formula (A). 6 The number of functional groups N per carbon atom.

[0159] N = I × K / t(A)

[0160] I: Absorbance

[0161] K: Correction coefficient

[0162] t: Membrane thickness (mm)

[0163] For reference, the absorption frequencies, molar absorptivity, and correction factors for the functional groups in the examples are shown in Table 2. Furthermore, the molar absorptivity was determined using FT-IR measurement data from the low-molecular-weight model compounds.

[0164] [Table 2]

[0165] Table 2

[0166]

[0167] (Mel flow rate (MFR))

[0168] Regarding the MFR of fluorinated copolymers, according to ASTM D-1238, the mass (g / 10 min) of polymer flowing out of a die with an inner diameter of 2 mm and a length of 8 mm is measured every 10 minutes using a melt flow index tester G-01 (manufactured by Toyo Seiki Co., Ltd.) at 372°C and a load of 5 kg, and the MFR is calculated accordingly.

[0169] (Melting point)

[0170] Regarding the melting point of the fluorinated copolymer, a differential scanning calorimeter (trade name: X-DSC7000, manufactured by Hitachi High-Tech Science) was used to perform a first heating from 200°C to 350°C at a heating rate of 10°C / min. Then, the temperature was cooled from 350°C to 200°C at a cooling rate of 10°C / min. A second heating was then performed from 200°C to 350°C at a heating rate of 10°C / min. The melting point was determined from the peak value of the melting curve generated during the second heating process.

[0171] Example 1

[0172] 40.25 kg of deionized water and 0.423 kg of methanol were added to a 174 L autoclave equipped with a stirrer, and the autoclave was thoroughly purged with nitrogen under vacuum. Afterward, the autoclave was degassed under vacuum, and 40.25 kg of HFP and 1.17 kg of PPVE were added to the vacuum-sealed autoclave. The autoclave was then heated to 25.5 °C. Next, TFE was added until the internal pressure of the autoclave reached 0.892 MPa. Then, 1.25 kg of 8% by mass di(ω-hydroperfluorohexanoyl) peroxide solution (hereinafter referred to as DHP) was added to the autoclave to begin polymerization. The internal pressure of the autoclave at the start of polymerization was set to 0.892 MPa, and this pressure was maintained by continuously adding TFE. 0.423 kg of methanol was added 1.5 hours after the start of polymerization. Two hours after the start of polymerization, 1.25 kg of DHP was added, and four hours later, with the internal pressure reduced by 0.002 MPa. Six hours later, 0.96 kg of DHP was added, with the internal pressure reduced by 0.002 MPa each time. Thereafter, 0.25 kg of DHP was added every two hours until the reaction was complete, with the internal pressure reduced by 0.002 MPa each time.

[0173] It should be noted that 0.24 kg of PPVE was added at the points when the TFE addition reached 8.1 kg, 16.2 kg, and 24.3 kg, respectively. Additionally, 0.423 kg of methanol was added to the autoclave at the points when the TFE addition reached 6.0 kg and 18.1 kg, respectively. The polymerization was terminated when the TFE addition reached 40.25 kg. After polymerization, unreacted TFE and HFP were released, yielding a wet powder. This wet powder was then washed with pure water and dried at 150°C for 10 hours to obtain 44.9 kg of dry powder.

[0174] The obtained powder was melt-extruded at 370°C using a screw extruder (trade name: PCM46, manufactured by Chibei Co., Ltd.) to obtain copolymer granules. The obtained granules were then used to determine various physical properties using the method described above. The results are shown in Table 3.

[0175] Example 2

[0176] The amount of methanol added before polymerization was changed to 0.354 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.354 kg each time. The amount of PPVE added before polymerization was changed to 1.01 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.22 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.878 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. The HFP and PPVE contents were determined using the obtained granules by the above method. The results are shown in Table 3.

[0177] The obtained granules were degassed in an electric furnace at 200°C for 8 hours, then placed in a VVD-30 vacuum vibratory reactor (manufactured by Okawahara Seisakusho Co., Ltd.), and heated to 200°C. After evacuation, F2 gas diluted to 20% by volume with N2 gas was introduced to atmospheric pressure. 0.5 hours after the introduction of F2 gas, a temporary vacuum was applied, and F2 gas was introduced again. This process was repeated 0.5 hours later, followed by another vacuum and introduction of F2 gas. This process of introducing F2 gas and evacuating the vacuum was repeated every hour, and the reaction was carried out at 200°C for 8 hours. After the reaction, the reactor was completely replaced with N2 gas to terminate the fluorination reaction, yielding granules. Various physical properties of the obtained granules were measured using the above method. The results are shown in Table 3.

[0178] Example 3

[0179] The amount of methanol added before polymerization was changed to 0.335 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.335 kg each time. The amount of PPVE added before polymerization was changed to 0.82 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.19 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.866 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. Various physical properties were measured using the obtained granules according to the above method. The results are shown in Table 3.

[0180] Example 4

[0181] The amount of methanol added before polymerization was changed to 0.368 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.368 kg each time. The amount of PPVE added before polymerization was changed to 0.99 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.21 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.886 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. The HFP and PPVE contents were determined using the obtained granules by the above method. The results are shown in Table 3.

[0182] The obtained granules were degassed in an electric furnace at 200°C for 72 hours, then placed in a VVD-30 vacuum vibratory reactor (manufactured by Okawahara Manufacturing Co., Ltd.), and heated to 110°C. After evacuation, F2 gas diluted to 20% by volume with N2 gas was introduced to atmospheric pressure. 0.5 hours after the introduction of F2 gas, a temporary vacuum was applied, and F2 gas was introduced again. This process was repeated 0.5 hours later, followed by another vacuum and introduction of F2 gas. This process of introducing F2 gas and evacuating the vacuum was repeated every hour, and the reaction was carried out at 110°C for 8 hours. After the reaction was completed, the reactor was completely replaced with N2 gas to stop the fluorination reaction and obtain the granules. Various physical properties of the obtained granules were measured using the above method. The results are shown in Table 3.

[0183] Comparative Example 1

[0184] The amount of methanol added before polymerization was changed to 0.235 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.235 kg each time. The amount of PPVE added before polymerization was changed to 0.96 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.22 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.866 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. The HFP and PPVE contents were determined using the obtained granules by the above method. The results are shown in Table 3.

[0185] The obtained granules were fluorinated in the same manner as in Example 4. Using the obtained granules, various physical properties were determined by the methods described above. The results are shown in Table 3.

[0186] Comparative Example 2

[0187] The amount of methanol added before polymerization was changed to 0.276 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.276 kg each time. The amount of PPVE added before polymerization was changed to 0.88 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.22 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.843 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. Various physical properties were measured using the obtained granules according to the above method. The results are shown in Table 3.

[0188] Comparative Example 3

[0189] The amount of methanol added before polymerization was changed to 0.546 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.546 kg each time. The amount of PPVE added before polymerization was changed to 0.73 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.14 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.906 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. Various physical properties were measured using the obtained granules according to the above method. The results are shown in Table 3.

[0190] Comparative Example 4

[0191] 0.945 kg of deionized water and 0.012 kg of methanol were added to a 4 L autoclave equipped with a stirrer, and the autoclave was thoroughly purged with nitrogen under vacuum. Then, the autoclave was degassed under vacuum, and 0.945 kg of HFP was added to the vacuum-sealed autoclave. The autoclave was then heated to 25.5 °C. Next, TFE was added until the internal pressure of the autoclave reached 0.878 MPa. Then, 0.029 kg of 8% by mass di(ω-hydroperfluorohexanoyl) peroxide solution (hereinafter referred to as DHP) was added to the autoclave to begin polymerization. The internal pressure of the autoclave at the start of polymerization was set to 0.878 MPa, and this pressure was maintained by continuously adding TFE. 0.012 kg of methanol was added 1.5 hours after the start of polymerization. Two hours and four hours after the start of polymerization, 0.029 kg of DHP was added, and the internal pressure was reduced by 0.002 MPa. Six hours later, 0.022 kg was added, and the internal pressure was reduced by 0.002 MPa again. Additionally, when the amount of TFE added reached 0.141 kg, 0.012 kg of methanol was added to the autoclave. The polymerization was then terminated when the amount of TFE added reached 0.473 kg. After polymerization, unreacted TFE and HFP were released, yielding a wet powder. This wet powder was then washed with pure water and dried at 150°C for 10 hours to obtain 0.518 kg of dry powder.

[0192] The obtained powder is used The copolymer granules were obtained by melt extrusion at 370°C using a screw extruder (manufactured by Imoto Manufacturing Co., Ltd.). Various physical properties of the obtained granules were measured using the methods described above. The results are shown in Table 3.

[0193] Comparative Example 5

[0194] The amount of methanol added before polymerization was changed to 0.570 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.570 kg each time. The amount of PPVE added before polymerization was changed to 1.09 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.19 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.948 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. The HFP and PPVE contents were determined using the obtained granules by the above method. The results are shown in Table 3.

[0195] The obtained granules were fluorinated in the same manner as in Example 2. Using the obtained granules, various physical properties were determined by the methods described above. The results are shown in Table 3.

[0196] Comparative Example 6

[0197] The amount of methanol added before polymerization was changed to 0.411 kg, and the amount of methanol added in batches after polymerization began was also changed to 0.411 kg each time. The amount of PPVE added before polymerization was changed to 0.96 kg, and the amount of PPVE added in batches after polymerization began was also changed to 0.22 kg each time. The set pressure inside the autoclave before and after polymerization was changed to 0.866 MPa. Otherwise, copolymer granules were obtained in the same manner as in Example 1. The HFP and PPVE contents were determined using the obtained granules by the above method. The results are shown in Table 3.

[0198] The obtained granules were fluorinated in the same manner as in Example 2. Using the obtained granules, various physical properties were determined by the methods described above. The results are shown in Table 3.

[0199] Comparative Example 7

[0200] 945g of deionized water and 7.7g of methanol were added to a 4L autoclave equipped with a stirrer, and the autoclave was thoroughly purged with nitrogen under vacuum. Then, the autoclave was degassed under vacuum, and 945g of HFP and 23.6g of PEVE were added to the vacuum-sealed autoclave. The autoclave was heated to 25.5°C. Next, TFE was added until the internal pressure of the autoclave reached 0.881MPa. Then, 29.4g of 8% by mass di(ω-hydroperfluorohexanoyl) peroxide solution (hereinafter referred to as DHP) was added to the autoclave to begin polymerization. The internal pressure of the autoclave at the start of polymerization was set to 0.881MPa, and this pressure was maintained by continuously adding TFE. 7.7g of methanol was added 1.5 hours after the start of polymerization. Two hours and four hours after the start of polymerization, 29.4 g of DHP was added, and the internal pressure was reduced by 0.002 MPa. Six hours later, 22.6 g of DHP was added, and the internal pressure was reduced by 0.002 MPa each time. Thereafter, 6.0 g of DHP was added every two hours until the reaction was completed, and the internal pressure was reduced by 0.002 MPa each time.

[0201] It should be noted that 5.2g of PEVE was added at the points where TFE was continuously added to 190g and 380g, respectively. Additionally, 7.8g of methanol was added to the autoclave when TFE was added to 140g. The polymerization was terminated when TFE was added to 454g. After polymerization, unreacted TFE and HFP were released, yielding a wet powder. This wet powder was then washed with pure water and dried at 150℃ for 10 hours to obtain 509g of dry powder.

[0202] The obtained powder is used The copolymer granules were obtained by melt extrusion at 370°C using a screw extruder (manufactured by Imoto Manufacturing Co., Ltd.). The HFP and PEVE contents of the obtained granules were determined using the method described above. The results are shown in Table 3.

[0203] The obtained granules were degassed in an electric furnace at 200°C for 8 hours, then placed in a portable TVS1 type reactor (manufactured by a pressure-resistant glass industry company) and heated to 200°C. After evacuation, F2 gas diluted to 20% by volume with N2 gas was introduced to atmospheric pressure. 0.5 hours after the introduction of F2 gas, a temporary vacuum was applied, and F2 gas was introduced again. Then, after another 0.5 hours, a vacuum was applied again, and F2 gas was introduced again. This process of introducing F2 gas and evacuating vacuum was repeated every hour, and the reaction was carried out at 200°C for 8 hours. After the reaction was completed, the reactor was completely replaced with N2 gas to stop the fluorination reaction, yielding granules. Various physical properties of the obtained granules were determined using the above method. The results are shown in Table 3.

[0204] [Table 3]

[0205] Table 3

[0206]

[0207] The "<9" in Table 3 refers to the number of -CF2H groups being less than 9. The "<6" in Table 3 refers to the total number (functional group number N) of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, and -CONH2 being less than 6.

[0208] Next, the obtained granules were used to evaluate the following properties. The results are shown in Table 4.

[0209] (Abrasion test)

[0210] Using a granulation and hot-press molding machine, sheet-shaped test pieces with a thickness of approximately 0.2 mm were prepared, from which 10 cm × 10 cm test pieces were cut. The prepared test pieces were fixed on the test bench of a Tiber abrasion testing machine (No. 101 Special Type Tiber Abrasion Testing Machine, manufactured by Yasuda Seiki Co., Ltd.). Abrasion tests were conducted using the Tiber abrasion testing machine under the following conditions: test piece surface temperature 50°C, load 500 g, abrasion wheel CS-10 (grinding with #240 abrasive paper for 20 revolutions), and rotation speed 60 rpm. The weight of the test piece was measured after 1000 revolutions, and the same test piece was further tested after 7000 revolutions, and the weight of the test piece was measured again. The abrasion amount was calculated using the following formula.

[0211] Wear amount (mg) = M1 - M2

[0212] M1: Weight of the test piece after 1000 revolutions (mg)

[0213] M2: Weight of the test piece (mg) after 7000 revolutions.

[0214] (Hydrogen permeability coefficient)

[0215] A sheet-like test piece with a thickness of approximately 0.1 mm was prepared using granulation and a hot press molding machine. Using the obtained test piece, the hydrogen permeability was measured using a differential pressure gas permeability meter (L100-5000 type gas permeability meter, manufactured by Systech Illinois) according to the method described in JIS K7126-1:2006. The permeability area was found to be 50.24 cm². 2 The hydrogen permeability was measured at a test temperature of 60℃ and a test humidity of 0%RH. Using the obtained hydrogen permeability and the thickness of the test piece, the hydrogen permeability coefficient was calculated using the following formula.

[0216] Hydrogen permeability (cm) 3 ·mm / (m 2 ·24h·atm))=GTR×d

[0217] GTR: Hydrogen Transmission Rate (cm) 3 / (m 2 ·24h·atm))

[0218] d: Thickness of the test piece (mm)

[0219] (75℃ load deflection)

[0220] Using granulation and a hot press, sheet-like test pieces with a thickness of approximately 2.4 mm were prepared. 80 × 10 mm test pieces were cut from these pieces and heated in an electric furnace at 100°C for 20 hours. In addition to using the obtained test pieces, tests were conducted according to the method described in JIS K-K7191-1 using a heat distortion tester (manufactured by Yasuda Seiki Co., Ltd.) under the following conditions: test temperature 30°C–150°C, heating rate 120°C / hour, bending stress 1.8 MPa, and flatwise method. The load deflection was calculated using the following formula. Sheets with low load deflection at 75°C exhibit excellent rigidity at 75°C.

[0221] Load-induced deflection (%) = a2 / a1 × 100

[0222] a1: Thickness of the test piece before the test (mm)

[0223] a2: Deflection at 75℃ (mm)

[0224] (Tensile creep test)

[0225] Tensile creep strain was determined using a Hitachi High-Tech TMA-7100. Sheets approximately 0.1 mm thick were prepared using a granulator and thermoforming machine. Samples 2 mm wide and 22 mm long were then fabricated from these sheets. The samples were mounted in the measuring fixture with a 10 mm gap between the clamps. A cross-sectional load of 3.32 N / mm² was applied to the samples. 2 The sample was subjected to a load at 140°C, and the displacement (mm) of its length was measured from 90 minutes to 450 minutes after the start of the test. The ratio of the displacement (mm) to the initial sample length (10mm) was calculated (tensile creep strain (%)). Samples with low tensile creep strain (%) measured at 140°C for 450 minutes do not easily elongate even under prolonged tensile loads in high-temperature environments, demonstrating excellent high-temperature tensile creep resistance (140°C).

[0226] (Crack test caused by chemical immersion)

[0227] Using granulation and a thermoforming machine, molded bodies with a thickness of approximately 2 mm were produced. The resulting sheets were punched using a 13.5 mm × 38 mm rectangular dumbbell, yielding three test pieces. A 19 mm × 0.45 mm notch was cut at the center of the long side of each test piece according to ASTM D1693. The three notched test pieces and 25 g of N-methylpyrrolidone were placed in a 100 mL polypropylene bottle and heated at 150°C for 20 hours. The notched test pieces were then removed. The three notched test pieces were mounted in a stress cracking test fixture according to ASTM D1693 and heated at 150°C for 24 hours. The notches and their surrounding areas were visually observed, and the number of cracks was counted. The piece that did not develop cracks exhibited excellent solvent crack resistance.

[0228] ○: The number of cracks is 0

[0229] ×: The number of cracks is more than 1.

[0230] (Injection molding)

[0231] ·condition

[0232] The copolymer was injection molded using an injection molding machine (Sumitomo Heavy Industries, Ltd., SE50EV-A) with a barrel temperature of 385°C, a mold temperature of 180°C, and an injection speed of 20 mm / s. A Cr-plated mold (100 mm × 100 mm × 2.0 mm, thin-film gate, flow length from the gate 100 mm) was used for HPM38. The resulting injection-molded body was observed and evaluated according to the following criteria: Visual inspection was performed to check for any white opacity. The presence or absence of surface roughness was confirmed by contacting the surface of the injection-molded body.

[0233] 3: The injection-molded part is transparent throughout and has a smooth surface.

[0234] 2: A white cloudiness was observed within 1 cm of the gate of the mold, and the surface was smooth overall.

[0235] 1: A white cloudiness was observed within 1 cm of the location of the mold gate, and a rough surface was confirmed within 1 cm of the location of the mold gate.

[0236] 0: The copolymer is not filled in the mold, and the desired shape of the molded body cannot be obtained.

[0237] (Conditions for wire coating)

[0238] use A wire coating extrusion molding machine (manufactured by Tanabe Plastics Machinery Co., Ltd.) extrudes a fluorinated copolymer onto a copper conductor with a conductor diameter of 0.50 mm to obtain a coated wire at the following coating thickness. The wire coating extrusion molding conditions are as follows.

[0239] a) Core conductor: Conductor diameter 0.50mm

[0240] b) Coating thickness: 0.20mm

[0241] c) Diameter of the covered wire: 0.90mm

[0242] d) Wire pulling speed: 70m / min

[0243] e) Extrusion conditions:

[0244] • Single-screw extrusion molding machine with a barrel shaft diameter of 30mm and an L / D ratio of 22

[0245] • Mold (inner diameter) / piece (outer diameter) = 9.0mm / 5.0mm

[0246] Extruder set temperatures: Barrel section C-1 (320℃), Barrel section C-2 (350℃), Barrel section C-3 (370℃), Head H (380℃), Die head D-1 (380℃), Die head D-2 (380℃). Core wire preheating is set to 80℃.

[0247] (Cover disconnected)

[0248] If the wire coating process is continuous and the coating breaks more than once in 1 hour, it is considered that continuous forming is not possible (×), and if no coating breaks occur, it is considered that continuous forming is possible (○).

[0249] (spark)

[0250] A DENSOK HIGH FREQ SPARK TESTER was installed online on the wire sheath to evaluate for any defects in the wire sheath at 1500V. The process was repeated for 1 hour, and the number of sparks was counted.

[0251] (Membrane forming properties)

[0252] use An extruder (manufactured by Imoto Manufacturing Co., Ltd.) and a T-die are used to shape the granules into a film. The extrusion molding conditions are as follows.

[0253] a) Winding speed: 1m / minute

[0254] b) Roller temperature: 120℃

[0255] c) Membrane width: 70mm

[0256] d) Thickness: 0.10mm

[0257] e) Extrusion conditions:

[0258] • Single-screw extrusion molding machine with a barrel shaft diameter of 14mm and an L / D ratio of 20

[0259] Extruder set temperatures: Barrel section C-1 (330℃), Barrel section C-2 (350℃), Barrel section C-3 (365℃), T-die head (370℃)

[0260] The extrusion molding of the fluorinated copolymer continues until the fluorinated copolymer is stably extruded from the molding machine. Next, a film with a length of 11 m or more (70 mm wide) is produced by extruding the fluorinated copolymer to a thickness of 0.10 mm. A 10-11 m portion is cut from the end of the obtained film to prepare a test piece (1 m long, 70 mm wide) for measuring thickness variation. The thickness is measured at three locations: the center point in the width direction at the end of the film and two locations 25 mm away from that center point in the width direction. Furthermore, the thickness is measured at nine locations: three center points spaced 25 cm apart from the center point at one end of the film towards the other end, and two locations 25 mm away from each center point in the width direction. Of the total 12 measurements, those with 1 or fewer measurements outside the ±10% range of 0.10 mm are designated as ○, and those with 2 or more measurements outside the ±10% range of 0.10 mm are designated as ×.

[0261] (Immersion test in hydrogen peroxide water)

[0262] Using granulation and a hot press molding machine, sheets with a thickness of approximately 0.2 mm were made, and test sheets with a square diameter of 15 mm were prepared. Ten test sheets and 15 g of 3% (w / w) hydrogen peroxide aqueous solution were placed in a 50 mL polypropylene bottle. The solution was heated at 95°C for 20 hours and then cooled to room temperature. The test sheets were removed from the hydrogen peroxide aqueous solution, and TISAB solution (10) (manufactured by Kanto Chemical Co., Ltd.) was added to the remaining hydrogen peroxide aqueous solution. The fluoride ion concentration in the resulting hydrogen peroxide aqueous solution was measured using a fluoride ion meter. The fluoride ion concentration per unit weight of sheet (dissolved fluoride ion concentration) was calculated from the measured value according to the following formula.

[0263] Dissolved fluoride ion concentration (ppm) = Measured value (ppm) × Volume of hydrogen peroxide aqueous solution (g) / Weight of test piece (g)

[0264]

Claims

1. A fluorinated copolymer, comprising tetrafluoroethylene units, hexafluoropropylene units, perfluoro(propyl vinyl ether) units, and other monomer units, wherein, The content of tetrafluoroethylene units relative to all monomer units is 88.6%–91.5% by mass. The content of hexafluoropropylene units relative to all monomer units is 7.0%–8.5% by mass. The content of perfluoro(propyl vinyl ether) units is 1.5% to 2.9% by mass relative to all monomer units. The content of other monomer units is 0–2.9% by mass relative to all monomer units. The total content of tetrafluoroethylene units, hexafluoropropylene units, perfluoro(propyl vinyl ether) units, and other monomer units is 100% by mass. The melt flow rate at 372℃ is 9 g / 10 min to 15 g / 10 min.

2. The fluorinated copolymer as described in claim 1, wherein, The content of hexafluoropropylene units is 7.2% to 8.1% by mass relative to all monomer units.

3. The fluorinated copolymer as described in claim 1 or 2, wherein, The content of perfluoro(propyl vinyl ether) units is 1.7% to 2.2% by mass relative to all monomer units.

4. The fluorinated copolymer as described in claim 1 or 2, wherein, The melt flow rate at 372℃ is 10 g / 10 min to 14 g / 10 min.

5. The fluorinated copolymer as described in claim 1 or 2, wherein, The number of functional groups -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH relative to 10 6 The main chain has fewer than 90 carbon atoms.

6. An injection-molded article comprising any one of claims 1 to 5.

7. A coated wire having a coating layer comprising a fluorinated copolymer according to any one of claims 1 to 5.

8. A molded article comprising the fluorinated copolymer according to any one of claims 1 to 5, wherein, The molded body is a valve, connector, flow meter, wire sheath, or membrane.

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