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

Abstract

To provide a copolymer capable of obtaining a beautiful injection molded article by molding by an injection molding method and a molded article, forming an extremely thick coating layer having a uniform thickness on a core wire having a very large diameter by an injection molding method which is less likely to corrode a mold used for molding or a coating core wire and obtaining a molded article which has a small haze value, is very excellent in wear resistance and excellent in mechanical strength at 100°C, low carbon dioxide permeability, low chemical liquid permeability, rigidity at a high temperature of 110°C and non-adhesiveness, is less likely to cause damage or degradation even if a tensile load is applied repeatedly, has a sufficiently low water vapor permeability and is less likely to elute fluorine ions in an electrolytic solution.SOLUTION: There is provided a copolymer which contains a tetrafluoroethylene unit and a perfluoro(propyl vinyl ether) unit, wherein the content of the perfluoro(propyl vinyl ether) unit is 2.26 to 2.75 mol% based on the total monomer units and the melt flow rate at 372°C is 4.0 to 11.0 g / 10 min and the number of functional groups is 50 or less per main-chain carbon number of 106.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes a molding material for an ozone-resistant article made of a copolymer (A) having a melt flow rate of 0.1 to 50 g / 10 min, wherein the copolymer (A) is a copolymer composed of tetrafluoroethylene and perfluorovinyl ether, contains 3.5 mass% or more of perfluorovinyl ether units, has a melting point of 295°C or higher, and the number of unstable end groups is 50 or less per 1×10 6 carbons in the copolymer (A). A molding material for an ozone-resistant article is characterized by this.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the present disclosure, it is an object to provide a copolymer capable of obtaining a beautiful injection molded article by injection molding, being less likely to corrode a mold used for molding or a core wire to be coated, forming a very thick coating layer with a uniform thickness on a core wire having a very large diameter by an extrusion molding method, having a very small haze value, being very excellent in abrasion resistance, being excellent in mechanical strength at 100°C, low carbon dioxide permeability, low chemical solution permeability, high rigidity at 110°C high temperature, and non-stickiness, being less likely to be damaged or deteriorated even when a tensile load is repeatedly applied, having sufficient low water vapor permeability, and being less likely to elute fluoride ions into an electrolytic solution.

Means for Solving the Problems

[0005] According to the present disclosure, there is provided a copolymer containing tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, wherein the content of perfluoro(propyl vinyl ether) units is 2.26 to 2.75 mol% based on all monomer units, the melt flow rate at 372 °C is 4.0 to 11.0 g / 10 min, and the number of functional groups is 50 or less per 10 main chain carbon atoms 6 atoms.

[0006] In the copolymer of the present disclosure, the melt flow rate at 372 °C is preferably 5.0 to 10.0 g / 10 min.

[0007] Further, according to the present disclosure, there is provided an injection molded article containing the above copolymer.

[0008] Further, according to the present disclosure, there is provided a coated electric wire including a coating layer containing the above copolymer.

[0009] Further, according to the present disclosure, there is provided a molded article containing the above copolymer, wherein the molded article is a filter housing, a film, a bottle, an electric wire coating, or a tube.

Advantages of the Invention

[0010] According to the present disclosure, it is possible to obtain a beautiful injection molded article by injection molding, and it is difficult to corrode the mold used for molding or the core wire to be coated. By the extrusion molding method, a very thick coating layer can be formed with a uniform thickness on a core wire having a very large diameter. The haze value is very small, the abrasion resistance is very excellent, the mechanical strength at 100 °C, the low carbon dioxide permeability, the low chemical liquid permeability, the rigidity at 110 °C high temperature, and the non-stickiness are excellent. In addition, it is possible to provide a copolymer that is not easily damaged or deteriorated even when a tensile load is repeatedly applied, has sufficient low water vapor permeability, and is difficult to elute fluoride ions into the electrolytic solution, and thus obtain a molded article.

Modes for Carrying Out the Invention

[0011] Hereinafter, specific embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0012] The copolymer of the present disclosure contains tetrafluoroethylene (TFE) units and perfluoro(propyl vinyl ether) (PPVE) units.

[0013] A copolymer (PFA) containing TFE units and PPVE units is used as a material for forming a filter housing for filtering fluids such as chemical solutions. The pressure of the fluid passing through the filter housing frequently fluctuates when the fluid supply starts, stops, or the supply pressure of the fluid changes. When filtering high-pressure fluids or high-temperature fluids, the high-pressure fluids or high-temperature fluids pass through the filter housing. Therefore, as a material constituting the filter housing, a material excellent in durability against repeated stress and mechanical strength at high temperatures is required. At the same time, it is preferable to use a material with excellent transparency for the material constituting the filter housing so that a defoaming operation can be performed while visually checking the presence or absence of bubbles in the filter housing. Furthermore, it is necessary to use a material that has sufficient low water vapor permeability so as not to contaminate the chemical solution flowing through the filter housing with moisture, fluorine ions, etc., and is also excellent in low chemical solution permeability and suppresses the elution of fluorine ions from the material itself.

[0014] Patent Document 1 describes that a molding material for an ozone-resistant article having the above-described characteristics is a molding material excellent in ozone resistance while maintaining the chemical resistance, heat resistance, and mechanical properties of the fluororesin without impairing the physical properties and moldability of the fluororesin. However, there is a need for a copolymer that has sufficient mechanical strength at high temperatures, sufficient low water vapor permeability, and sufficient low chemical solution permeability, is less likely to elute fluorine ions, and can provide a molded body with a lower haze value and less likely to be damaged even when a tensile load is repeatedly applied compared to the molding material described in Patent Document 1.

[0015] Furthermore, in order to manufacture the filter housing with high productivity, it is preferable to mold the material using an injection molding method. With conventional materials, even if the material itself had excellent transparency, there was a problem that a filter housing with excellent transparency could not be obtained because the resulting injection molded product was cloudy or the surface was rough. Therefore, as a material constituting the filter housing, a material is required that not only has a small haze value of the material itself, but also has excellent moldability and does not lose its excellent transparency even after injection molding.

[0016] By appropriately adjusting the content of the PPVE unit, the melt flow rate (MFR), and the number of functional groups of the copolymer containing TFE units and PPVE units, it has been found that the moldability of the copolymer is significantly improved and at the same time, the mold used for molding is less likely to be corroded. Furthermore, by using such a copolymer, a molded product having a very small haze value, extremely excellent wear resistance, excellent mechanical strength at 100°C, low carbon dioxide permeability, low chemical solution permeability, excellent rigidity at 110°C high temperature, and non-stickiness, and being less likely to be damaged or deteriorated even when a tensile load is repeatedly applied, having sufficient low water vapor permeability, and being less likely to elute fluoride ions in the electrolytic solution has also been found.

[0017] Furthermore, the copolymer of the present disclosure can form a very thick coating layer with a uniform thickness on a very large diameter core wire by an extrusion molding method. Furthermore, the obtained coating layer is less likely to corrode the core wire. Thus, the copolymer of the present disclosure can be used not only as a material for a filter housing but also in a wide range of applications such as wire coating.

[0018] The copolymer of the present disclosure is a fluororesin with melt processability. Melt processability means that it is possible to melt and process the polymer using conventional processing equipment such as an extruder and an injection molding machine.

[0019] The content of the PPVE units in the copolymer is 2.26 to 2.75 mol%, preferably 2.28 mol% or more, more preferably 2.30 mol% or more, still more preferably 2.32 mol% or more, particularly preferably 2.34 mol% or more, most preferably 2.38 mol% or more, preferably 2.71 mol% or less, more preferably 2.68 mol% or less, still more preferably 2.65 mol% or less, particularly preferably 2.62 mol% or less, and most preferably 2.59 mol% or less, based on all monomer units. When the content of the PPVE units in the copolymer is within the above range, the haze value is very small, the abrasion resistance is very excellent, and it is excellent in mechanical strength at 100 °C, low carbon dioxide permeability, low chemical solution permeability, rigidity at 110 °C high temperature, and non-stickiness. In addition, even when a tensile load is repeatedly applied, the molded body is less likely to be damaged or deteriorated and has sufficient low water vapor permeability. If the content of the PPVE units in the copolymer is too small, the haze value increases and the abrasion resistance deteriorates. If the content of the PPVE units in the copolymer is too large, a molded body having sufficient low water vapor permeability cannot be obtained, a molded body having sufficient low carbon dioxide permeability cannot be obtained, a molded body having sufficient rigidity at 110 °C high temperature cannot be obtained, or a molded body excellent in durability against repeated tensile loads cannot be obtained.

[0020] The content of the TFE units in the copolymer is preferably 97.25 to 97.74 mol%, more preferably 97.29 mol% or more, still more preferably 97.32 mol% or more, yet still more preferably 97.35 mol% or more, particularly preferably 97.38 mol% or more, most preferably 97.41 mol% or more, more preferably 97.72 mol% or less, still more preferably 97.70 mol% or less, yet still more preferably 97.68 mol% or less, particularly preferably 97.66 mol% or less, and most preferably 97.62 mol% or less, based on all monomer units. If the content of the TFE units in the copolymer is too large, the haze value may increase. If the content of the TFE units in the copolymer is too small, there is a possibility that a molded body having sufficient low water vapor permeability cannot be obtained.

[0021] In the present disclosure, the content of each monomer unit in the copolymer is 19 measured by the F-NMR method.

[0022] The copolymer may also contain monomer units derived from monomers copolymerizable with TFE and PPVE. In this case, the content of the monomer units copolymerizable with TFE and PPVE is preferably 0 to 0.45 mol%, more preferably 0.01 to 0.30 mol% or less, and still more preferably 0.05 to 0.20 mol% based on the total monomer units of the copolymer.

[0023] Examples of the monomers copolymerizable 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 represented by CF2=CF-ORf 1 (wherein Rf 1 is a perfluoroalkyl group having 1 to 8 carbon atoms), perfluoro(alkyl vinyl ether) [PAVE] (excluding PPVE) represented by CF2=CF-OCH2-Rf 1 (wherein Rf 1 represents a perfluoroalkyl group having 1 to 5 carbon atoms), and alkyl perfluorovinyl ether derivatives represented by CF2=CF-OCH2-Rf, etc. Among them, HFP is preferred.

[0024] 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.

[0025] The melt flow rate (MFR) of the copolymer is 4.0 to 11.0 g / 10 min. The MFR of the copolymer is preferably 4.1 g / 10 min or more, more preferably 4.2 g / 10 min or more, still more preferably 4.3 g / 10 min or more, yet more preferably 4.5 g / 10 min or more, particularly preferably 5.0 g / 10 min or more, most preferably 6.0 g / 10 min or more, preferably 10.9 g / 10 min or less, more preferably 10.5 g / 10 min or less, still more preferably 10.4 g / 10 min or less, yet more preferably 10.0 g / 10 min or less, particularly preferably 9.5 g / 10 min or less, and most preferably 9.0 g / 10 min or less. When the MFR of the copolymer is within the above range, the moldability of the copolymer is improved, the haze value is small, it is less likely to be damaged even when a tensile load is repeatedly applied, and it is excellent in abrasion resistance, mechanical strength at 100°C, low carbon dioxide permeability, low chemical liquid permeability, and rigidity at 110°C high temperature, and a molded article having sufficient low water vapor permeability can be obtained.

[0026] In the present disclosure, MFR is a value obtained as the mass (g / 10 min) of the polymer flowing out per 10 minutes from a nozzle having an inner diameter of 2.1 mm and a length of 8 mm under a load of 5 kg at 372°C using a melt indexer in accordance with ASTM D1238.

[0027] MFR can be adjusted by adjusting the type and amount of the polymerization initiator used when polymerizing the monomers, the type and amount of the chain transfer agent, and the like.

[0028] The number of carbon atoms in the main chain of the copolymer is 10 6 The number of functional groups per unit is 50 or less. The number of carbon atoms in the main chain of the copolymer is 10 6The number of functional groups per unit is preferably 40 or less, more preferably 30 or less, still more preferably 20 or less, yet still more preferably 15 or less, particularly preferably 10 or less, and most preferably less than 6. When the number of functional groups of the copolymer is within the above range, even if the copolymer is molded by filling it into a mold, it is difficult to corrode the mold, and even when used as an electric wire coating, it is difficult to corrode the core wire. Furthermore, a molded article excellent in non-stickiness, low carbon dioxide permeability, and low chemical liquid permeability and difficult to elute fluoride ions into the electrolytic solution can be obtained. In particular, by appropriately adjusting the content of the PPVE unit, the melt flow rate (MFR), and the number of functional groups of the copolymer containing TFE units and PPVE units, a molded article showing excellent low permeability to various chemical liquids such as dimethyl carbonate and ethyl acetate can be obtained.

[0029] Infrared spectroscopic analysis can be used for the identification of the types of the above functional groups and the measurement of the number of functional groups.

[0030] Specifically, the number of functional groups is measured by the following method. First, the above copolymer is molded by cold pressing to produce a film with a thickness of 0.25 to 0.30 mm. This film is analyzed by Fourier transform infrared spectroscopy to obtain the infrared absorption spectrum of the above copolymer, and a difference spectrum from a base spectrum that is completely fluorinated and has no functional groups is obtained. From the absorption peak of a specific functional group appearing in this difference spectrum, according to the following formula (A), the number of functional groups N per 1 × 10 6 carbon atoms in the above copolymer is calculated.

[0031] N = I × K / t (A) I: Absorbance K: Correction coefficient t: Thickness of the film (mm)

[0032] For reference, the absorption frequency, molar extinction coefficient, and correction coefficient for some functional groups are shown in Table 1. The molar extinction coefficient was determined from the FT-IR measurement data of low molecular weight model compounds.

Table 1

[0033] The absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are several tens of wavenumbers (cm -1 ) lower than the absorption frequencies of -CF2H, -COF, -COOH free and -COOH bonded, -COOCH3, and -CONH2 shown in the table respectively.

[0034] For example, the number of functional groups of -COF is the sum of the number of functional groups determined from the absorption peak of the absorption frequency 1883 cm -1 due to -CF2COF and the number of functional groups determined from the absorption peak of the absorption frequency 1840 cm -1 due to -CH2COF.

[0035] The functional groups are the functional groups present at the main chain end or side chain end of the copolymer, and the functional groups present in the main chain or side chain. The number of functional groups may be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH.

[0036] The above functional groups are introduced into the copolymer, for example, by a chain transfer agent or a polymerization initiator used in producing 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 at the main chain end of the copolymer. Also, by polymerizing a monomer having a functional group, the above functional group is introduced at the side chain end of the copolymer.

[0037] By fluorinating the copolymer having such functional groups, a copolymer having the number of functional groups within the above range can be obtained. That is, the copolymer of the present disclosure is preferably fluorinated. The copolymer of the present disclosure preferably has a -CF3 end group.

[0038] The melting point of the copolymer is preferably 285 to 310 °C, more preferably 290 °C or higher, still more preferably 294 °C or higher, particularly preferably 296 °C or higher, most preferably 298 °C or higher, and more preferably 305 °C or lower. By having the melting point within the above range, a copolymer can be obtained that provides a molded article having particularly excellent mechanical strength at high temperatures.

[0039] In the present disclosure, the melting point can be measured using a differential scanning calorimeter [DSC].

[0040] The copolymer of the present disclosure preferably has a haze value of 7.5% or less. By having the haze value within the above range, for example, when a molded article such as a pipe, joint, bottle, or flow meter is obtained using the copolymer of the present disclosure, visual observation inside the molded article or observation with a camera or the like becomes very easy, and it becomes very easy to confirm the flow rate and remaining amount of the content. The haze value can be reduced by adjusting the content of the PPVE unit and the melt flow rate (MFR) of the copolymer. In the present disclosure, the haze value can be measured according to JIS K 7136.

[0041] The copolymer of the present disclosure preferably has a tensile strength at 100 °C of 20.0 MPa or more, more preferably 20.5 MPa or more, and still more preferably 22.0 MPa or more. By having the tensile strength at 100 °C within the above range, even when the obtained molded article is used at high temperatures, deformation is suppressed and the long life of the molded article becomes possible. The tensile strength at 100 °C can be increased by adjusting the content of the PPVE unit and the melt flow rate (MFR) of the copolymer. In the present disclosure, the tensile strength at 100 °C can be measured according to ASTM D638.

[0042] The water vapor permeability of the copolymer is preferably 18.0 g·cm / m 2 or less, more preferably 17.5 g·cm / m 2 or less, still more preferably 17.0 g·cm / m 2The following is the case. Since the content of the PPVE units, the melt flow rate (MFR), and the number of functional groups of the copolymer containing TFE units and PPVE units of the present disclosure are appropriately adjusted, it has sufficient low water vapor permeability. Therefore, for example, a molded body such as a filter housing obtained using the copolymer of the present disclosure can be suitably used for transporting a chemical solution that dislikes the mixing of moisture such as water vapor in the outside air.

[0043] In the present disclosure, the water vapor permeability can be measured under the conditions of a temperature of 95°C and a period of 30 days. The specific measurement of the water vapor permeability can be carried out by the method described in the examples.

[0044] The carbon dioxide permeability coefficient of the copolymer is preferably 2000 cm 3 ·mm / (m 2 ·24h·atm) or less. Since the content of the PPVE units, the melt flow rate (MFR), and the number of functional groups of the copolymer containing TFE units and PPVE units of the present disclosure are appropriately adjusted, it has excellent low carbon dioxide permeability. Therefore, by using the copolymer of the present disclosure, it is possible to surely suppress the permeation of carbon dioxide from the outside, and to obtain a molded body such as a bottle that can maintain the quality of the chemical solution contained inside for a long period of time.

[0045] In the present disclosure, 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.

[0046] The electrolyte permeability of the copolymer is preferably 8.5 g·cm / m 2 or less, and more preferably 8.2 g·cm / m 2 or less. Since the content of the PPVE units, the melt flow rate (MFR), and the number of functional groups of the copolymer containing TFE units and PPVE units of the present disclosure are appropriately adjusted, it has excellent low electrolyte permeability. That is, by using the copolymer of the present disclosure, it is possible to obtain a molded body that is less permeable to chemical solutions such as electrolytes.

[0047] In the present disclosure, 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 performed by the method described in the examples.

[0048] The ethyl acetate permeability of the copolymer is preferably 6.9 g·cm / m 2 or less, more preferably 6.6 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 in the present disclosure are appropriately adjusted, it has excellent low ethyl acetate permeability. That is, by using the copolymer of the present disclosure, a molded article through which a chemical solution such as ethyl acetate hardly permeates can be obtained.

[0049] In the present disclosure, the ethyl acetate permeability can be measured under the conditions of a temperature of 60°C for 45 days. The specific measurement of the ethyl acetate permeability can be performed by the method described in the examples.

[0050] In the copolymer of the present disclosure, the amount of eluted fluoride ions detected in the electrolyte immersion test is preferably 1.0 ppm or less, more preferably 0.8 ppm or less, and still more preferably 0.7 ppm or less on a mass basis. When the amount of eluted fluoride ions is within the above range, the generation of gases such as HF in the non-aqueous electrolyte battery can be further suppressed, and the deterioration and shortening of the battery life of the non-aqueous electrolyte battery can be further suppressed.

[0051] In the present disclosure, the electrolyte immersion test is performed by using a copolymer to prepare a test piece having a weight corresponding to 10 molded articles (15 mm × 15 mm × 0.2 mm), and placing the test piece and 2 g of dimethyl carbonate (DMC) in a glass sample bottle in a constant temperature bath at 80°C and leaving it for 144 hours.

[0052] The copolymer of the present disclosure can be produced by a polymerization method such as suspension polymerization, solution polymerization, emulsion polymerization, bulk polymerization, etc. As the polymerization method, emulsion polymerization or suspension polymerization is preferred. In these polymerizations, each condition such as temperature, pressure, the polymerization initiator and other additives can be appropriately set according to the composition and amount of the copolymer.

[0053] As the polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.

[0054] The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide. For example, Dialkyl peroxydicarbonates such as dinormalpropyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate; Peroxy esters such as t-butyl peroxyisobutyrate, t-butyl peroxypivalate; Dialkyl peroxides such as di-t-butyl peroxide; Di[fluoro(or fluorochloro)acyl]peroxides; etc. are mentioned as typical ones.

[0055] Examples of the di[fluoro(or fluorochloro)acyl]peroxides include diacyl peroxides represented by [(RfCOO)-]2 (Rf is a perfluoroalkyl group, ω-hydroperfluoroalkyl group or fluorochloroalkyl group).

[0056] Examples of the di[fluoro(or fluorochloro)acyl]peroxides include di(ω-hydroxy-dodecafluorohexanoyl)peroxide, di(ω-hydroxy-tetradecafluoroheptanoyl)peroxide, di(ω-hydroxy-hexadecafluorononanoyl)peroxide, di(perfluoropropionyl)peroxide, di(perfluorobutyryl)peroxide, di(perfluorovaleryl)peroxide, di(perfluorohexanoyl)peroxide, di(perfluoroheptanoyl)peroxide, di(perfluorooctanoyl)peroxide, di(perfluorononanoyl)peroxide, di(ω-chloro-hexafluorobutyryl)peroxide, di(ω-chloro-decafluorohexanoyl)peroxide, di(ω-chloro-tetradecafluorooctanoyl)peroxide, ω-hydroxy-dodecafluoroheptanoyl-ω-hydroxy-hexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydroxydodecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl)peroxide, di(trichlorooctafluorohexanoyl)peroxide, di(tetrachloroundecafluorooctanoyl)peroxide, di(pentachlorotetradecafluorodecanoyl)peroxide, di(undecachlorotriacontapluorodocosanoyl)peroxide and the like.

[0057] The water-soluble radical polymerization initiator may be a known water-soluble peroxide, and examples thereof include ammonium salts, potassium salts, sodium salts such as persulfuric acid, perboric acid, perchloric acid, phosphoric acid, percarbonic acid, organic peroxides such as disuccinic acid peroxide, diglutaric acid peroxide, t-butyl permaleate, t-butyl hydroperoxide and the like. A reducing agent such as sulfite may be used in combination with the peroxide, and the amount used may be 0.1 to 20 times that of the peroxide.

[0058] In the case of polymerization, a surfactant, a chain transfer agent, and a solvent can be used, and those conventionally known can be used respectively.

[0059] As the surfactant, known surfactants can be used. For example, nonionic surfactants, anionic surfactants, cationic surfactants, etc. can be used. Among them, fluorine-containing anionic surfactants are preferred, and those containing an ether-bonded oxygen (i.e., oxygen atoms may be inserted between carbon atoms) and having 4 to 20 carbon atoms, linear or branched fluorine-containing anionic surfactants are more preferred. The addition amount of the surfactant (relative to the polymerization water) is preferably 50 to 5000 ppm.

[0060] Examples of the chain transfer agent include hydrocarbons such as ethane, isopentane, n-hexane, and cyclohexane; aromatics such as toluene and xylene; ketones such as acetone; acetate esters such as ethyl acetate and butyl acetate; alcohols such as methanol and ethanol; mercaptans such as methyl mercaptan; and halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride, and methyl chloride. The addition amount of the chain transfer agent can vary depending on the magnitude of the chain transfer constant of the compound used, but it is usually used in the range of 0.01 to 20% by mass based on the polymerization solvent.

[0061] Examples of the solvent include water and a mixed solvent of water and alcohol.

[0062] In suspension polymerization, a fluorinated solvent may be used in addition to water. Examples of the fluorinated solvent include hydrochlorofluoroalkanes such as CH3CClF2, CH3CCl2F, CF3CF2CCl2H, and CF2ClCF2CFHCl; chlorofluorocarbons such as CF2ClCFClCF2CF3 and CF3CFClCFClCF3; hydrofluorocarbons such as CF3CFHCFHCF2CF2CF3, CF2HCF2CF2CF2CF2H, and CF3CF2CF2CF2CF2CF2CF2H; hydrofluoroethers such as CH3OC2F5, CH3OC3F5, CF3CF2CH2OCHF2, CF3CHFCF2OCH3, CHF2CF2OCH2F, (CF3)2CHCF2OCH3, CF3CF2CH2OCH2CHF2, and CF3CHFCF2OCH2CF3; perfluoroalkanes such as perfluorocyclobutane, CF3CF2CF2CF3, CF3CF2CF2CF2CF3, and CF3CF2CF2CF2CF2CF3. Among them, perfluoroalkanes are preferred. The amount of the fluorinated solvent used is preferably 10 to 100% by mass based on the aqueous medium from the viewpoints of suspension property and economy.

[0063] The polymerization temperature is not particularly limited and may be 0 to 100 °C. The polymerization pressure is appropriately determined according to other polymerization conditions such as the type, amount, and vapor pressure of the solvent used and the polymerization temperature, and is usually 0 to 9.8 MPaG.

[0064] When an aqueous dispersion containing a copolymer is obtained by the polymerization reaction, the copolymer contained in the aqueous dispersion can be recovered by coagulating, washing, and drying the copolymer. When the copolymer is obtained as a slurry by the polymerization reaction, the copolymer can be recovered by taking out the slurry from the reaction vessel, washing, and drying. By drying, the copolymer can be recovered in the form of a powder.

[0065] The copolymer obtained by polymerization may be formed into pellets. The molding method for forming into pellets is not particularly limited, and a conventionally known method can be used. For example, a method of melt-extruding the copolymer using a single-screw extruder, a twin-screw extruder, or a tandem extruder and cutting it into a predetermined length to form it into pellets can be mentioned. The extrusion temperature during melt extrusion needs to be changed depending on the melt viscosity of the copolymer and the manufacturing method, and is preferably from the melting point of the copolymer + 20°C to the melting point of the copolymer + 140°C. The cutting method of the copolymer is not particularly limited, and conventionally known methods such as a strand cut method, a hot cut method, an under-water cut method, and a sheet cut method can be adopted. The obtained pellets may be heated to remove volatile components in the pellets (degassing treatment). The obtained pellets may be treated by contacting them with warm water at 30 to 200°C, steam at 100 to 200°C, or warm air at 40 to 200°C.

[0066] The copolymer obtained by polymerization may be fluorinated. The fluorination treatment can be carried out by bringing the non-fluorinated copolymer into contact with a fluorine-containing compound. By the fluorination treatment, thermally unstable functional groups such as -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, etc. of the copolymer, and functional groups such as -CF2H which are relatively thermally stable can be converted into -CF3 which is extremely thermally stable. As a result, the total number (number of functional groups) of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, and -CF2H of the copolymer can be easily adjusted to the above-mentioned range.

[0067] The fluorine-containing compound is not particularly limited, but examples include fluorine radical sources that generate fluorine radicals under fluorination treatment conditions. Examples of the above-mentioned fluorine radical sources include F2 gas, CoF3, AgF2, UF6, OF2, N2F2, CF3OF, and halogen fluorides (for example, IF5, ClF3).

[0068] The fluorine radical source such as F2 gas may be of 100% concentration, but from the perspective of safety, it is preferably mixed with an inert gas and diluted to 5 to 50% by mass for use, and more preferably diluted to 15 to 30% by mass for use. Examples of the inert gas include nitrogen gas, helium gas, argon gas, etc., and nitrogen gas is preferred from an economic perspective.

[0069] The conditions of the fluorination treatment are not particularly limited, and the molten copolymer and the fluorine-containing compound may be brought into contact with each other. Usually, it can be carried out at a temperature below the melting point of the copolymer, preferably 20 to 240 °C, more preferably 100 to 220 °C. The fluorination treatment is generally carried out for 1 to 30 hours, preferably 5 to 25 hours. The fluorination treatment is preferably carried out by bringing the non-fluorinated copolymer into contact with fluorine gas (F2 gas).

[0070] The copolymer of the present disclosure and other components as needed may be mixed to obtain a composition. Examples of 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, softening agents, dehydrofluorinating agents, etc.

[0071] Examples of the filler include 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. Examples of the conductive agent include carbon black, etc. Examples of the plasticizer include dioctyl phthalate, pentaerythritol, etc. Examples of the processing aid include carnauba wax, sulfone compounds, low molecular weight polyethylene, fluorine-based aids, etc. Examples of the dehydrofluorinating agent include organic onium, amidines, etc.

[0072] As the above-mentioned other components, other polymers other than the above-mentioned copolymer may be used. Examples of other polymers include fluororesins, fluororubbers, non-fluorinated polymers, etc., other than the above-mentioned copolymer.

[0073] As a method for producing the above composition, a method of dry-mixing a copolymer and other components, a method of previously mixing a copolymer and other components with a mixer and then melt-kneading them with a kneader, a melt extruder, etc. can be mentioned.

[0074] The copolymer or the above composition of the present disclosure can be used as a processing aid, a molding material, etc., but it is preferably used as a molding material. An aqueous dispersion, solution, suspension, and copolymer / solvent system of the copolymer of the present disclosure are also available, and these can be applied as a paint, used for encapsulation, impregnation, film casting, etc. However, since the copolymer of the present disclosure has the above-mentioned characteristics, it is preferably used as the above molding material.

[0075] The copolymer or the above composition of the present disclosure may be molded to obtain a molded article.

[0076] The method for molding the above copolymer or the above composition is not particularly limited, and examples include an injection molding method, an extrusion molding method, a compression molding method, a blow molding method, a transfer molding method, a rotational molding method, a rotolining molding method, etc. Among the molding methods, an extrusion molding method, a compression molding method, an injection molding method, or a transfer molding method is preferable, and an injection molding method, an extrusion molding method, or a transfer molding method is more preferable because a molded article can be produced with high productivity, and an injection molding method is even more preferable. That is, as the molded article, an extrusion molded article, a compression molded article, an injection molded article, or a transfer molded article is preferably used, and an injection molded article, an extrusion molded article, or a transfer molded article is more preferably used because it can be produced with high productivity, and an injection molded article is even more preferably used. By molding the copolymer of the present disclosure by an injection molding method, an injection molded article with a beautiful appearance can be obtained without corroding the mold used for molding.

[0077] Examples of the molded article containing the copolymer of the present disclosure include nuts, bolts, joints, films, bottles, gaskets, wire coatings, tubes, hoses, pipes, valves, sheets, seals, packings, tanks, rollers, containers, cocks, connectors, filter housings, filter cages, flow meters, pumps, wafer carriers, wafer boxes, and the like.

[0078] The copolymer, the above composition, or the above molded article of the present disclosure can be used, for example, in the following applications. Films for food packaging, lining materials for fluid transfer lines used in food manufacturing processes, fluid transfer members for food manufacturing apparatuses such as packings, seal materials, and sheets; Drug stoppers for drugs, packaging films, lining materials for fluid transfer lines used in drug manufacturing processes, fluid transfer members for drug solutions such as packings, seal materials, and sheets; Inner surface lining members for chemical solution tanks and pipes in chemical plants and semiconductor factories; O-ring, tubes, packings, valve core materials, hoses, seal materials, etc. used in the fuel system and peripheral devices of automobiles, fuel transfer members such as hoses and seal materials used in the AT devices of automobiles; Flange gaskets, shaft seals, valve stem seals, seal materials, hoses, etc. used in the engines and peripheral devices of automobiles, other automobile members such as brake hoses, air conditioner hoses, radiator hoses, and wire coating materials; Chemical solution transfer members for semiconductor devices such as O-rings, tubes, packings, valve core materials, hoses, seal materials, rolls, gaskets, diaphragms, and joints in semiconductor manufacturing apparatuses; Coating and ink members such as coating rolls, hoses, tubes, and containers for ink in coating equipment; Tubes such as tubes for food and drink or hoses for food and drink, food and drink transfer members such as tubes, hoses, belts, packings, and joints, food packaging materials, and glass cooking appliances; Waste liquid transport members such as tubes and hoses for waste liquid transport; High-temperature liquid transport members such as tubes and hoses for high-temperature liquid transport; Steam pipes, steam pipe members such as hoses; Anti-corrosion tapes for pipes such as tapes wound around pipes on the decks of ships; Various coating materials such as wire coating materials, optical fiber coating materials, transparent surface coating materials provided on the light incident side surface of the photo-electrochemical element of a solar cell, and back surface agents; Sliding members such as diaphragms of diaphragm pumps and various packings; Agricultural films, weather-resistant covers such as various roofing materials and side walls; Interior materials used in the construction field, coating materials for glasses such as non-combustible fire safety glasses; Lining materials such as laminated steel plates used in the field of household appliances;

[0079] As the fuel transfer member used in the fuel system of the above-mentioned automobile, fuel hoses, filler hoses, evap hoses, etc. may be further mentioned. The above fuel transfer member can also be used as a fuel transfer member for sour gasoline-resistant, alcohol fuel-resistant, fuel containing gasoline additives such as methyl tertiary butyl ether and amine-resistant.

[0080] The above-mentioned medicine plugs and packaging films for chemicals have excellent chemical resistance against acids and the like. Further, as the above-mentioned chemical liquid transfer member, an anti-corrosion tape wound around chemical plant pipes can also be mentioned.

[0081] As the above-mentioned molded body, automobile radiator tanks, chemical liquid tanks, bellows, spacers, rollers, gasoline tanks, waste liquid transport containers, high-temperature liquid transport containers, fishing and fish farming tanks, etc. may be further mentioned.

[0082] As the above-mentioned molded body, members used for automobile bumpers, door trims, instrument panels, food processing devices, cooking appliances, water and oil repellent glasses, lighting related devices, display panels and housings of OA devices, illuminated signboards, displays, liquid crystal displays, mobile phones, printed circuit boards, electrical and electronic components, sundries, trash cans, bathtubs, unit baths, ventilation fans, lighting frames, etc. may be further mentioned.

[0083] The molded article containing the copolymer of the present disclosure has a very low haze value, is very excellent in abrasion resistance, excellent in mechanical strength at 100°C, low carbon dioxide permeability, low chemical liquid permeability, rigidity at 110°C high temperature and non-stickiness, and is also difficult to be damaged or deteriorated even when a tensile load is repeatedly applied, has sufficient low water vapor permeability, and is difficult to elute fluoride ions in the electrolytic solution. Therefore, it can be suitably used for nuts, bolts, joints, packings, valves, cocks, connectors, filter housings, filter cages, flow meters, pumps and the like. The filter housing containing the copolymer of the present disclosure has a very low haze value, so it is excellent in internal visibility, and for example, a defoaming operation can be easily performed. In addition, it can be suitably used as a piping member (especially a joint) used for transferring a chemical liquid and a flow meter housing having a chemical liquid flow path in a flow meter. The piping member and the flow meter housing of the present disclosure have a very low haze value, are very excellent in abrasion resistance, excellent in mechanical strength at 100°C, low carbon dioxide permeability, low chemical liquid permeability, rigidity at 110°C high temperature and non-stickiness, and are also difficult to be damaged or deteriorated even when a tensile load is repeatedly applied, have sufficient low water vapor permeability, and are difficult to elute fluoride ions in the electrolytic solution. Therefore, the piping member and the flow meter housing of the present disclosure are excellent in internal visibility. Especially in the flow meter housing, the internal float can be easily observed by visual inspection or a camera, etc., and it can also be suitably used for measuring the flow rate of a chemical liquid at about 100°C, and is difficult to be damaged even when stress is repeatedly applied according to the start, stop, and flow rate change of the chemical liquid flow. Furthermore, the piping member and the flow meter housing of the present disclosure can be manufactured by an injection molding method without corroding the mold used for molding, and have a beautiful appearance.

[0084] The molded article containing the copolymer of the present disclosure can be easily manufactured by an injection molding method without corroding the mold, has a very low haze value, is very excellent in abrasion resistance, has mechanical strength at 100 °C, low carbon dioxide permeability, low chemical liquid permeability, excellent rigidity at 110 °C high temperature and non-stickiness, and is not easily damaged or deteriorated even when a tensile load is repeatedly applied, has sufficient low water vapor permeability, and is not likely to elute fluoride ions into the electrolytic solution. Therefore, it can be suitably used as a compressed member such as a gasket or a packing. The compressed member of the present disclosure may be a gasket or a packing. The gasket or packing of the present disclosure can be manufactured at low cost by an injection molding method without corroding the mold, is not easily damaged even when installed at a location where opening and closing are repeated frequently, and is excellent in mechanical strength at 100 °C. The compressed member of the present disclosure is excellent in low water vapor permeability and is not easily damaged even when a repeated stress is applied. Therefore, it can be suitably used as a pipe member for transporting a chemical liquid that dislikes the mixing of moisture such as water vapor in the outside air.

[0085] The size and shape of the compressed member of the present disclosure may be appropriately set according to the application and are not particularly limited. The shape of the compressed member of the present disclosure may be, for example, annular. Further, the compressed member of the present disclosure may have a shape such as circular, oval, or a square with rounded corners in a plan view and have a through hole in the central portion thereof.

[0086] The compressed member of the present disclosure is preferably used as a member for constituting a non-aqueous electrolyte battery. The compressed member of the present disclosure is excellent in low water vapor permeability and is not likely to elute fluoride ions into the electrolytic solution. Therefore, it is particularly suitable as a member 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 disclosure may have a liquid contact surface with the non-aqueous electrolyte in the non-aqueous electrolyte battery.

[0087] The compressed member of the present disclosure is less likely to elute fluoride ions into the non-aqueous electrolyte. Therefore, by using the compressed member of the present disclosure, an increase in the fluoride ion concentration in the non-aqueous electrolyte can be suppressed. As a result, by using the compressed member of the present disclosure, generation of gases such as HF in the non-aqueous electrolyte battery can be suppressed, and deterioration and shortening of the battery life of the non-aqueous electrolyte battery can be suppressed.

[0088] Since the compressed member of the present disclosure can further suppress generation of gases such as HF in the non-aqueous electrolyte battery and further suppress deterioration and shortening of the battery life of the non-aqueous electrolyte battery, the amount of eluted fluoride ions detected in the electrolyte immersion test is preferably 1.0 ppm or less, preferably 0.8 ppm or less, and more preferably 0.7 ppm or less on a mass basis. The electrolyte immersion test can be performed by using the compressed member to prepare a test piece having a weight corresponding to 10 molded bodies (15 mm × 15 mm × 0.2 mm), and placing a glass sample bottle containing the test piece and 2 g of dimethyl carbonate (DMC) in a thermostatic bath at 80°C and leaving it for 144 hours.

[0089] The compressed member of the present disclosure is less likely to permeate water vapor. Therefore, by using the compressed member of the present disclosure, permeation of water vapor from the outside into the secondary battery can be suppressed. As a result, deterioration and shortening of the battery life of the non-aqueous electrolyte battery can be suppressed by using the compressed member of the present disclosure.

[0090] Since the water vapor permeability of the compressed member of the present disclosure can further suppress deterioration and shortening of the battery life of the non-aqueous electrolyte battery, it is preferably 18.0 g·cm / m 2 or less, more preferably 17.5 g·cm / m 2 or less, and even more preferably 17.0 g·cm / m 2 or less. The water vapor permeability of the compressed member can be measured under the conditions of a temperature of 95°C for 30 days.

[0091] The non-aqueous electrolyte battery is not particularly limited as long as it is a battery equipped with a non-aqueous electrolyte. For example, a lithium-ion secondary battery, a lithium-ion capacitor, etc. can be mentioned. In addition, examples of the members constituting the non-aqueous electrolyte battery include a sealing member, an insulating member, etc.

[0092] The above non-aqueous electrolyte is not particularly limited, but one or more known solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate can be used. The non-aqueous electrolyte battery may further include an electrolyte. The above electrolyte is not particularly limited, but LiClO4, LiAsF6, LiPF6, LiBF4, LiCl, LiBr, CH3SO3Li, CF3SO3Li, cesium carbonate, etc. can be used.

[0093] The compressed member of the present disclosure can be suitably used as, for example, a sealing member such as a sealing gasket or a sealing packing, or an insulating member such as an insulating gasket or an insulating packing. The sealing member is a member used to prevent the leakage of liquid or gas or the intrusion of liquid or gas from the outside. The insulating member is a member used to insulate electricity. The compressed member of the present disclosure may be a member used for both sealing and insulating purposes.

[0094] Since the compressed member of the present disclosure is less likely to elute fluoride ions in the electrolyte, it can be suitably used as a sealing member for non-aqueous electrolyte batteries or an insulating member for non-aqueous electrolyte batteries. In addition, since the compressed member of the present disclosure contains the above copolymer, it has excellent insulating properties. Therefore, when the compressed member of the present disclosure is used as an insulating member, it adheres firmly to two or more conductive members and prevents short circuits over a long period of time.

[0095] The copolymer of the present disclosure is less likely to corrode the core wire to be coated. Furthermore, by molding the copolymer of the present disclosure by an extrusion molding method, a coating layer can be formed with a uniform thickness on a core wire having a very large diameter, so that it can be suitably used as a material for forming an electric wire coating. Therefore, a coated electric wire provided with a coating layer containing the copolymer of the present disclosure has excellent electrical characteristics because the core wire is less likely to corrode and there is almost no variation in the outer diameter.

[0096] When attempting to form a very thick coating layer with a uniform thickness on a core wire having a very large diameter, it takes time for the molten coating layer to solidify, and the weight of the coating layer is also large. Therefore, when using a conventional copolymer, there is a problem that the coating layer deforms under its own weight before solidifying, making it difficult to form a coating layer with a uniform thickness. By using the copolymer of the present disclosure, a very thick coating layer can be formed with a uniform thickness on a core wire having a very large diameter.

[0097] The coated electric wire includes a core wire and a coating layer provided around the core wire and containing the copolymer of the present disclosure. For example, an extruded molded body obtained by melt-extruding the copolymer of the present disclosure on the core wire can be used as the coating layer. The coated electric wire is suitable for LAN cables (Eathernet Cable), high-frequency transmission cables, flat cables, heat-resistant cables, etc., and among them, it is particularly suitable for transmission cables such as LAN cables (Eathernet Cable) and high-frequency transmission cables.

[0098] As the material of the core wire, for example, metal conductor materials such as copper and aluminum can be used. The core wire preferably has a diameter of 0.02 to 3 mm. The diameter of the core wire is more preferably 0.04 mm or more, still more 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.

[0099] As specific examples of the core wire, for example, AWG (American Wire Gauge)-46 (solid copper wire with a diameter of 40 micrometers), AWG-26 (solid copper wire with a diameter of 404 micrometers), AWG-24 (solid copper wire with a diameter of 510 micrometers), AWG-22 (solid copper wire with a diameter of 635 micrometers), etc. may be used.

[0100] The thickness of the coating layer is preferably 0.1 to 3.0 mm. It is also preferable that the thickness of the coating layer is 2.0 mm or less.

[0101] Examples of the high-frequency transmission cable include coaxial cables. 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 order from the core part to the outer peripheral part. The molded body containing the copolymer of the present disclosure can be preferably used as an insulating coating layer containing the copolymer. The thickness of each layer in the above structure is not particularly limited, but usually, the inner conductor has a diameter of about 0.1 to 3 mm, the insulating coating layer has a thickness of about 0.3 to 3 mm, the outer conductor layer has a thickness of about 0.5 to 10 mm, and the protective coating layer has a thickness of about 0.5 to 2 mm.

[0102] The coating layer may contain bubbles, and it is preferable that the bubbles are uniformly distributed in the coating layer.

[0103] The average bubble diameter of the bubbles is not limited, but 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 extremely preferably 23 μm or less. Also, the average bubble diameter is preferably 0.1 μm or more, and more preferably 1 μm or more. The average bubble diameter can be obtained by taking an electron microscope image of the cross-section of the electric wire, calculating the diameter of each bubble by image processing, and averaging them.

[0104] The coating layer may have a foaming ratio of 20% or more. More preferably, it is 30% or more, still more preferably 33% or more, and even more preferably 35% or more. The upper limit is not particularly limited, for example, it is 80%. The upper limit of the foaming ratio may be 60%. The foaming ratio is a value obtained as ((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 application, for example, by adjusting the insertion amount of gas in the extruder described later, or by selecting the type of gas to be dissolved.

[0105] The coated wire may be provided with another layer between the above-mentioned core wire and the above-mentioned coating layer, or may be provided with still another layer (outer layer) around the coating layer. When the coating layer contains air bubbles, the wire of the present disclosure may have 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 covering the outer layer, or even a three-layer structure (skin-foam-skin) with a non-foamed layer covering the outer layer of the skin-foam. The non-foamed layer is not particularly limited and may be a resin layer made of a TFE / HFP copolymer, a TFE / PAVE copolymer, a TFE / ethylene copolymer, a vinylidene fluoride polymer, a polyolefin resin such as polyethylene [PE], a resin such as polyvinyl chloride [PVC].

[0106] The coated wire can be manufactured, for example, by using an extruder to heat the copolymer and extrude it onto the core wire in a state where the copolymer is melted to form the coating layer.

[0107] When forming the coating layer, it is also possible to form the above-mentioned coating layer containing air bubbles by heating the copolymer and introducing gas into the copolymer in a state where the copolymer is melted. As the gas, for example, a gas such as chlorodifluoromethane, nitrogen, carbon dioxide or a mixture of the above gases can be used. The gas may be introduced as a pressurized gas into the heated copolymer, or may be generated by mixing a chemical foaming agent into the copolymer. The gas dissolves in the molten copolymer.

[0108] In addition, the copolymer of the present disclosure can be suitably used as a material for products for high-frequency signal transmission.

[0109] The products for high-frequency signal transmission are not particularly limited as long as they are products used for the transmission of high-frequency signals. Examples include (1) insulating plates for high-frequency circuits, insulators for connecting components, molded plates such as printed wiring boards; (2) molded bodies such as bases for high-frequency vacuum tubes and antenna covers; and (3) coated electric wires such as coaxial cables and LAN cables. The products for high-frequency signal transmission can be suitably used in devices that utilize microwaves, particularly microwaves in the range of 3 to 30 GHz, such as satellite communication devices and mobile phone base stations.

[0110] In the products for high-frequency signal transmission, the copolymer of the present disclosure can be suitably used as an insulator in terms of its low dielectric loss tangent.

[0111] Among the above (1) molded plates, printed wiring boards are preferred in terms of obtaining good electrical properties. The printed wiring boards are not particularly limited, and examples include printed wiring boards for electronic circuits of mobile phones, various computers, communication devices, etc. Among the above (2) molded bodies, antenna covers are preferred in terms of their low dielectric loss.

[0112] The copolymer of the present disclosure can be molded by an injection molding method to obtain a beautiful sheet. In addition, the molded body containing the copolymer of the present disclosure has a very small haze value, is very excellent in wear resistance, excellent in mechanical strength at 100°C, low carbon dioxide permeability, low chemical solution permeability, high rigidity at 110°C high temperature and non-stickiness, is not easily damaged or deteriorated even when a tensile load is repeatedly applied, has sufficient low water vapor permeability, and is not easily elute fluoride ions in the electrolyte. Therefore, the molded body containing the copolymer of the present disclosure can be suitably used as a film or a sheet.

[0113] The film of the present disclosure is particularly excellent in non-stickiness. Therefore, even when the film of the present disclosure is heat-pressed with a resin such as an epoxy resin or toner, etc., the resin, toner, etc. can be peeled off from the film without the two adhering to each other.

[0114] The film of the present disclosure is useful as a release film. The release film can be produced by molding the copolymer of the present disclosure by melt extrusion molding, calendering, press molding, casting molding, etc. From the viewpoint of obtaining a uniform thin film, the release film can be produced by melt extrusion molding.

[0115] The film of the present disclosure can be applied to the surface of a roll used in OA equipment. Further, the copolymer of the present disclosure can be molded into a required shape by extrusion molding, compression molding, press molding, etc. and formed into a sheet shape, film shape, tube shape, etc., and can be used as a surface material for an OA equipment roll or OA equipment belt, etc. In particular, a thin tube or film can be produced by the melt extrusion molding method.

[0116] The molded body containing the copolymer of the present disclosure has a very small haze value, is very excellent in abrasion resistance, excellent in mechanical strength at 100 °C, low carbon dioxide permeability, low chemical liquid permeability, high rigidity at 110 °C high temperature and non-stickiness, and is not easily damaged or deteriorated even when a tensile load is repeatedly applied, has sufficient low water vapor permeability, and is not easily eluted with fluoride ions in an electrolytic solution. Therefore, it can be suitably used as a bottle or tube. The bottle or tube of the present disclosure can easily visually recognize the content and is not easily damaged during use.

[0117] As described above, the embodiments have been described, but it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims.

Examples

[0118] Next, embodiments of the present disclosure will be described with examples, but the present disclosure is not limited to such examples only.

[0119] The numerical values of each example were measured by the following methods.

[0120] (Content of monomer unit) The content of each monomer unit was measured by an NMR analyzer (for example, AVANCE300 high-temperature probe manufactured by Bruker BioSpin).

[0121] (Melt flow rate (MFR)) According to ASTM D1238, using a melt indexer G-01 (manufactured by Toyo Seiki Seisakusho), the mass (g / 10 min) of the polymer flowing out per 10 minutes from a nozzle with an inner diameter of 2.1 mm and a length of 8 mm under a load of 5 kg at 372 °C was determined.

[0122] (Number of functional groups) The copolymer pellets were molded by cold pressing to produce a film with a thickness of 0.25 to 0.30 mm. This film was scanned 40 times by a Fourier transform infrared spectroscopic analyzer [FT-IR (Spectrum One, manufactured by PerkinElmer)] and analyzed to obtain an infrared absorption spectrum, and a difference spectrum from a base spectrum that was completely fluorinated and had no functional groups was obtained. From the absorption peak of a specific functional group appearing in this difference spectrum, according to the following formula (A), the number of functional groups N per 1 × 10 6 carbon atoms in the sample was calculated. N = I × K / t (A) I: Absorbance K: Correction coefficient t: Thickness of the film (mm) For reference, Table 2 shows the absorption frequency, molar extinction coefficient, and correction coefficient for the functional groups in the present disclosure. The molar extinction coefficient was determined from the FT-IR measurement data of low molecular weight model compounds.

[0123]

Table 2

[0124] (Melting point) Using a differential scanning calorimeter (trade name: X-DSC7000, manufactured by Hitachi High-Tech Science Corporation), the first temperature increase was carried out from 200 °C to 350 °C at a heating rate of 10 °C / min. Subsequently, it was cooled from 350 °C to 200 °C at a cooling rate of 10 °C / min, and then, again, the second temperature increase was carried out from 200 °C to 350 °C at a heating rate of 10 °C / min. The melting point was determined from the melting curve peak generated during the second temperature increase process.

[0125] Example 1 26.6 L of pure water was charged into an autoclave with a volume of 174 L. After sufficient nitrogen replacement, 30.4 kg of perfluorocyclobutane, 1.96 kg of perfluoro(propyl vinyl ether) (PPVE), and 0.11 kg of methanol were charged, and the temperature inside the system was maintained at 35 °C and the stirring speed at 200 rpm. Next, tetrafluoroethylene (TFE) was pressured in until 0.58 MPa, and then 0.010 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was charged to initiate polymerization. Since the pressure inside the system decreased as the polymerization proceeded, TFE was continuously supplied to keep the pressure constant, and 0.064 kg of PPVE was added every 1 kg of TFE supply, and the polymerization was continued for 7 hours. After discharging TFE and returning the inside of the autoclave to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 15 kg of powder.

[0126] 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. The PPVE content was measured by the method described above using the obtained pellets. The results are shown in Table 3.

[0127] The obtained pellets were placed into a vacuum vibration reaction device VVD-30 (manufactured by Okawara Seisakusho), and the temperature was raised to 210°C. After evacuation, F2 gas diluted to 20% by volume with N2 gas was introduced up to atmospheric pressure. Half an hour after the introduction of F2 gas, evacuation was performed once, and then F2 gas was introduced again. Further, half an hour after that, evacuation was performed again, and then F2 gas was introduced again. Thereafter, the above operations of introducing F2 gas and evacuation were continuously performed once per 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 sufficiently replaced with N2 gas to terminate the fluorination reaction. Using the fluorinated pellets, various physical properties were measured by the method described above. The results are shown in Table 3.

[0128] Example 2 2.04 kg of PPVE, 0.15 kg of methanol, and 0.066 kg of PPVE was additionally added per 1 kg of TFE supply. Except that the temperature increase of the vacuum vibration reaction device was 170°C and the reaction was changed to 5 hours at a temperature of 170°C, fluorinated pellets were obtained in the same manner as in Example 1. The results are shown in Table 3.

[0129] Example 3 2.12 kg of PPVE, 0.18 kg of methanol, and 0.068 kg of PPVE was additionally added per 1 kg of TFE supply. Except that the polymerization time was changed to 7.5 hours, fluorinated pellets were obtained in the same manner as in Example 1. The results are shown in Table 3.

[0130] Example 4 2.20 kg of PPVE, 0.21 kg of methanol, and 0.071 kg of PPVE was additionally added per 1 kg of TFE supply. Except that the polymerization time was changed to 7.5 hours, fluorinated pellets were obtained in the same manner as in Example 1. The results are shown in Table 3.

[0131] Example 5 2.20 kg of PPVE, 0.23 kg of methanol, and 0.071 kg of PPVE was additionally added per 1 kg of TFE supply. Except that the polymerization time was changed to 7.5 hours, fluorinated pellets were obtained in the same manner as in Example 1. The results are shown in Table 3.

[0132] Comparative Example 1 Except that 1.76 kg of PPVE was changed to 0.21 kg of methanol and 0.058 kg of PPVE was additionally added per 1 kg of TFE supply, fluorinated pellets were obtained in the same manner as in Example 1. The results are shown in Table 3.

[0133] Comparative Example 2 49.0 L of pure water was charged into a 174 L autoclave, and after sufficient nitrogen replacement, 40.7 kg of perfluorocyclobutane, 2.58 kg of perfluoro(propyl vinyl ether) (PPVE), and 1.75 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 into the system up to 0.64 MPa, and then 0.041 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was charged to initiate polymerization. Since the pressure inside the system decreased as the polymerization progressed, TFE was continuously supplied to keep the pressure constant, and 0.071 kg of PPVE was additionally added per 1 kg of TFE supply, and the polymerization was continued for 18.5 hours. After releasing TFE and returning the inside of the autoclave to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 30 kg of powder. The obtained powder was melt-extruded at 360 °C using a screw extruder (trade name: PCM46, manufactured by Ikegai Corporation) to obtain pellets of a TFE / PPVE copolymer. The PPVE content was measured using the above-described method using the obtained pellets. The results are shown in Table 3. The obtained pellets were fluorinated in the same manner as in Example 1 to obtain fluorinated pellets. Using the fluorinated pellets, various physical properties were measured using the above-described method. The results are shown in Table 3.

[0134] Comparative Example 3 Except that 2.12 kg of PPVE was changed to 0.03 kg of methanol, 0.068 kg of PPVE was additionally added per 1 kg of TFE supply, and the polymerization time was changed to 7 hours, fluorinated pellets were obtained in the same manner as in Comparative Example 1. The results are shown in Table 3.

[0135] Comparative Example 4 Except that the amount of methanol was changed to 0.14 kg, non-fluorinated pellets were obtained in the same manner as in Example 1. The results are shown in Table 3.

[0136] Comparative Example 5 51.8 L of pure water was charged into a 174 L autoclave, and after sufficient nitrogen replacement, 40.9 kg of perfluorocyclobutane, 2.88 kg of perfluoro(propyl vinyl ether) (PPVE), and 1.56 kg of methanol were charged. The temperature inside the system was maintained at 35 °C and the stirring speed was maintained at 200 rpm. Next, tetrafluoroethylene (TFE) was pressured in until 0.64 MPa, and then 0.051 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was charged to initiate polymerization. Since the pressure inside the system decreased as the polymerization proceeded, TFE was continuously supplied to keep the pressure constant, and 0.060 kg of PPVE was additionally charged every 1 kg of TFE supplied. Polymerization was terminated when the additional input amount of TFE reached 40.9 kg. After discharging the unreacted TFE and returning the inside of the autoclave to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 41.0 kg of powder.

[0137] Using the obtained powder, a fluorination reaction was carried out in the same manner as in Example 1 to obtain fluorinated pellets. The results are shown in Table 3.

[0138]

Table 3

[0139] The description “<6” in Table 3 means that the number of functional groups is less than 6.

[0140] Next, using the obtained pellets, the following properties were evaluated. The results are shown in Table 4.

[0141] (Haze value) Using pellets and a heat press machine, a sheet with a thickness of approximately 1.0 mm was produced. Using a haze meter (product name: NDH7000SP, manufactured by Nippon Denshoku Industries Co., Ltd.), in accordance with JIS K 7136, the sheet was immersed in a quartz cell filled with pure water, and the haze value was measured.

[0142] (Tensile strength (TS) at 100 °C) In accordance with ASTM D638, the tensile strength at 100 °C was measured.

[0143] (Water vapor permeability) Using pellets and a heat press machine, a sheet-like test piece with a thickness of approximately 0.2 mm was produced. 18 g of water was placed in a test cup (permeation area 12.56 cm 2 ), covered with the sheet-like test piece, clamped with a PTFE gasket and tightened to seal. The sheet-like test piece was brought into contact with water, held at 95 °C for 30 days, then taken out, left at room temperature for 2 hours, and the mass loss was measured. The water vapor permeability (g·cm / m 2 ) was measured by the following formula. Water vapor permeability (g·cm / m 2 ) = mass loss (g) × thickness of sheet-like test piece (cm) / permeation area (m 2 )

[0144] (Injection moldability) Using an injection molding machine (Sumitomo Heavy Industries, Ltd., SE50EV-A), with the cylinder temperature at 395 °C, the mold temperature at 220 °C, and the injection speed at 3 mm / s, the copolymer was injection molded. As the mold, a mold with Cr plating on HPM38 (100 mm × 100 mm × 3 mmt, film gate, flow length 10 mm) was used. The obtained injection molded product was observed and evaluated according to the following criteria. The presence or absence of cloudiness was confirmed visually. The presence or absence of surface roughness was confirmed by touching the surface of the injection molded product. 3: The entire injection molded product is transparent and the entire surface is smooth 2: Cloudiness is observed within a range of 1 cm from the location where the gate of the mold is located, and the entire surface is smooth Cloudiness is observed within a range of 1 cm from the location where the mold gate is located, and roughness is confirmed on the surface within a range of 1 cm from the location where the mold gate is located. 0: The copolymer does not fill the entire mold, and a molded article of the desired shape cannot be obtained.

[0145] (Electrolyte immersion test) Approximately 5 g of pellets were placed in a mold (inner diameter 120 mm, height 38 mm), melted at 370 °C for 20 minutes using a hot plate press, and then water-cooled while applying pressure at 1 MPa (resin pressure) to produce a molded article with a thickness of approximately 0.2 mm. Thereafter, a test piece of 15 mm square was produced using the obtained molded article.

[0146] Ten obtained test pieces and 2 g of dimethyl carbonate (DMC) were placed in a 20 mL glass sample bottle, and the lid of the sample bottle was closed. The sample bottle was placed in a constant temperature bath at 80 °C and left for 144 hours to immerse the test pieces in DMC. Thereafter, the sample bottle was taken out of the constant temperature bath, cooled to room temperature, and then the test pieces were taken out of the sample bottle. The DMC remaining after taking out the test pieces was air-dried for 24 hours in a room controlled at 25 °C with the sample bottle still containing it, and 2 g of ultrapure water was added. The obtained aqueous solution was transferred to the measurement cell of an ion chromatograph system, and the amount of fluoride ions in this aqueous solution was measured using an ion chromatograph system (Dionex ICS-2100 manufactured by Thermo Fisher Scientific).

[0147] (Ethyl acetate permeability) Using pellets and a heat press molding machine, a sheet-like test piece with a thickness of approximately 0.1 mm was produced. 10 g of ethyl acetate was placed in a test cup (permeation area 12.56 cm 2 ), covered with the sheet-like test piece, clamped with a PTFE gasket, and tightened to seal. After maintaining at 60 °C for 45 days with the sheet-like test piece in contact with ethyl acetate, it was taken out, left at room temperature for 1 hour, and then the mass reduction amount was measured. The ethyl acetate permeability (g·cm / m 2 ) was determined by the following formula. Ethyl acetate (g·cm / m2 ) = Mass reduction amount (g) × Thickness of sheet-like test piece (cm) / Permeation area (m 2 )

[0148] (Deflection rate under load at 110°C) Using pellets and a heat press molding machine, a sheet-like test piece with a thickness of approximately 4.2 mm was prepared. From this, a test piece of 80 × 10 mm was cut out and heated in an electric furnace at 100°C for 20 hours. Except for using the obtained test piece, in accordance with the method described in JIS K-K 7191-1, a heat distortion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) was used to conduct tests under the conditions of a test temperature of 30 to 150°C, a heating rate of 120°C / hour, a bending stress of 1.8 MPa, and the flatwise method. The deflection rate under load was obtained by the following formula. A sheet with a small deflection rate under load at 110°C has excellent rigidity at a high temperature of 110°C. Deflection rate under load (%) = a2 / a1 × 100 a1: Thickness of test piece before test (mm) a2: Amount of deflection at 110°C (mm)

[0149] (Tensile strength after 100,000 cycles) Using a fatigue testing machine MMT-250NV-10 manufactured by Shimadzu Corporation, the tensile strength after 100,000 cycles was measured. Using pellets and a heat press molding machine, a sheet with a thickness of approximately 2.4 mm was prepared. Using an ASTM D1708 micro dumbbell, a sample with a dumbbell shape (thickness 2.4 mm, width 5.0 mm, measurement section length 22 mm) was prepared. The sample was attached to a measurement jig, and with the sample attached, the measurement jig was placed in a constant temperature bath at 150°C. Tensile in the uniaxial direction was repeated at a stroke of 0.2 mm and a frequency of 100 Hz, and the tensile strength for each tensile (tensile strength when the stroke is +0.2 mm) was measured. The tensile strength after 100,000 cycles was calculated from the measured values according to the following formula. In this example, the cross-sectional area of the sample is 12.0 mm 2 is Tensile strength after 100,000 cycles (mN / mm 2 ) = Tensile strength (after 100,000 cycles) (mN) / Cross-sectional area of sample (mm 2 )

[0150] The tensile strength after 100,000 cycles is the ratio of the tensile strength when a repeated load is applied 100,000 times to the cross-sectional area of the sample. A sheet with a high tensile strength after 100,000 cycles maintains a high tensile strength even after a load is applied 100,000 times and is excellent in durability against repeated loads.

[0151] (Mold corrosion test) Put 20 g of pellets into a glass container (50 ml screw tube), and suspend a metal column (5 mm square in cross-section, 30 mm in length) formed by HPM38 (Cr plating) or HPM38 (Ni plating) so that it does not touch the pellets in the glass container. Then, cover the glass container with an aluminum foil. Put the glass container in this state into an oven and heat it at 380 °C for 3 hours. After that, take out the heated glass container from the oven, cool it to room temperature, and visually observe the degree of corrosion on the surface of the metal column. The degree of corrosion was judged according to the following criteria. ○: No corrosion is observed △: Slight corrosion is observed ×: Corrosion is observed

[0152] (Wire coating test) Using a 30 mmφ wire coating forming machine (manufactured by Tanabe Plastic Machinery Co., Ltd.), a copolymer was extruded and coated on a copper conductor with a conductor diameter of 1.00 mm to obtain a coated wire. The wire coating extrusion forming conditions are as follows. a) Core conductor: Conductor diameter 1.00 mm b) Coating thickness: 0.50 mm c) Coated wire diameter: 2.00 mm d) Wire pulling speed: 7 m / min e) Extrusion conditions: · Single-screw extrusion molding machine with a cylinder shaft diameter = 20 mm and L / D = 22 · Die (inner diameter) / Chip (outer diameter) = 30.0 mm / 10.0 mm The set temperature of the extruder: Barrel part C-1 (330 °C), Barrel part C-2 (360 °C), Barrel part C-3 (375 °C), Head part H (390 °C), Die part D-1 (405 °C), Die part D-2 (395 °C). The preheating of the core wire was set at 80 °C.

[0153] (Variation in outer diameter) Using an outer diameter measuring instrument (ODAC18XY manufactured by Zumbach), the outer diameter of the obtained coated electric wire was continuously measured for 1 hour. Among the measured outer diameter values, the variation value of the outer diameter was obtained by rounding off the third decimal place of the outer diameter value that deviated most from a predetermined outer diameter value (2.00 mm). The ratio of the absolute value of the difference between the predetermined outer diameter and the variation value of the outer diameter to the predetermined outer diameter (variation rate of the outer diameter) was calculated and evaluated according to the following criteria. (Variation rate of outer diameter (%)) = |(Variation value of outer diameter) - (Predetermined outer diameter)| / (Predetermined outer diameter) × 100 ±1%: The variation rate of the outer diameter is 1% or less. ±2%: The variation rate of the outer diameter is more than 1% and 2% or less. ×: The variation rate of the outer diameter is more than 2%.

[0154] (Core wire corrosion test) The obtained coated electric wire was cut into pieces with a length of 20 cm and left standing in a constant temperature and humidity chamber (Junior SD - 01 manufactured by FATC) at 60°C and 95% humidity for 2 weeks. Then, the coating layer was peeled off to expose the conductor, and the surface of the conductor was visually observed and evaluated according to the following criteria. ○: No corrosion is observed. ×: Corrosion is observed.

[0155] (Toner release test) Using a φ14 mm extruder (manufactured by Imoto Seisakusho) and a T - die, a film was produced. The extrusion molding conditions are as follows. a) Take - up speed: 1 m / min b) Roll temperature: 120°C c) Film width: 70 mm d) Thickness: 0.10 mm e) Extrusion conditions: · Single - screw extruder with a cylinder shaft diameter of 14 mm and L / D = 20 Set temperature of the extruder: Barrel part C - 1 (330°C), Barrel part C - 2 (350°C), Barrel part C - 3 (370°C), T - die part (380°C)

[0156] A 50 mm × 50 mm test piece was cut out from the obtained 0.10 mm thick film. The obtained test piece was laid on a SUS tray, and 3 g of black toner powder was scattered thereon in a circular shape with a diameter of about 30 mm. The lid of the tray was closed, and the tray was placed in a thermostatic bath heated to 160 °C with the inside being in a closed space state. After 10 minutes, the tray was taken out, allowed to cool to room temperature, and then the test piece was taken out from the tray. The melted and solidified matter of the black toner was peeled off from the test piece, and the peeled surface of the test piece was visually observed and evaluated according to the following criteria. ○: No black deposits are observed on the peeled surface of the test piece ×: Black deposits are observed on the peeled surface of the test piece

[0157] (Wear test) Using pellets and a heat press molding machine, a sheet-like test piece with a thickness of about 0.2 mm was produced, and a 10 cm × 10 cm test piece was cut out therefrom. The produced test piece was fixed to the test bench of a Taber abrasion tester (No. 101 special type Taber type abrasion tester, manufactured by Yasuda Seiki Seisakusho Co., Ltd.), and a wear test was conducted using the Taber abrasion tester under the conditions of a load of 500 g, a wear wheel CS-10 (polished 20 times with abrasive paper #240), and a rotational speed of 60 rpm. The weight of the test piece after 1000 rotations was measured, and the weight of the test piece was further measured after 10000 rotations with the same test piece. The wear amount was determined by the following formula. Wear amount (mg) = M1 - M2 M1: Weight of the test piece after 1000 rotations (mg) M2: Weight of the test piece after 10000 rotations (mg)

[0158] (Carbon dioxide permeability coefficient) Using pellets and a heat press molding machine, a sheet-like test piece with a thickness of about 0.1 mm was produced. Using the obtained test piece, the carbon dioxide permeability was measured using a differential pressure type gas permeation meter (L100-5000 type gas permeation meter, manufactured by Systech illinois) according to the method described in JIS K7126-1:2006. The permeation area was 50.24 cm 2, the numerical value of the carbon dioxide permeability at 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 from the following formula. Carbon dioxide permeability coefficient (cm 3 ·mm / (m 2 ·24h·atm)) = GTR × d GTR: Carbon dioxide permeability (cm 3 / (m 2 ·24h·atm)) d: Test piece thickness (mm)

[0159] (Electrolyte permeability) Using a pellet and a heat press molding machine, a sheet-like test piece with a thickness of about 0.2 mm was prepared. 10 g of dimethyl carbonate (DMC) was placed in a test cup (permeation area 12.56 cm 2 ), covered with a sheet-like test piece, clamped with a PTFE gasket, and tightened and sealed. After maintaining at 60 °C for 30 days with the sheet-like test piece in contact with DMC, it was taken out, left at room temperature for 1 hour, and then the mass reduction amount was measured. The DMC permeability (g·cm / m 2 ) was determined by the following formula. Electrolyte permeability (g·cm / m 2 ) = Mass reduction amount (g) × Thickness of sheet-like test piece (cm) / Permeation area (m 2 )

[0160] (Tube formability) Using the pellets obtained in the examples, a tube with an outer diameter of 10.0 mm and a wall thickness of 1.0 mm was extruded using a φ30 mm extrusion molding machine (manufactured by Tanabe Plastics Machinery). The extrusion molding conditions are as follows. a) Die inner diameter: 20 mm b) Mandrel outer diameter: 13 mm c) Sizing die inner diameter: 10.5 mm d) Take-up speed: 0.4 m / min e) Outer diameter: 10.0 mm f) Wall thickness: 1.0 mm g) Extrusion conditions: · Single screw extrusion molding machine with a cylinder shaft diameter of 30 mm and L / D = 22 Extruder set temperature: Barrel section C-1 (330 °C), Barrel section C-2 (365 °C), Barrel section C-3 (380 °C), Head section H-1 (380 °C), Die section D-1 (390 °C), Die section D-2 (390 °C) The obtained tube was observed and evaluated according to the following criteria. The appearance of the tube was confirmed visually. ○: Good appearance ×: Poor appearance, such as the cross-section not being circular, being flattened, or having uneven wall thickness

[0161] (Dielectric loss tangent) By melt-molding the pellets, a cylindrical test piece with a diameter of 2 mm was prepared. The prepared test piece was set in a 6 GHz cavity resonator manufactured by Kanto Electronic Application Development Co., Ltd. and measured with a network analyzer manufactured by Agilent Technologies. By analyzing the measurement results with the analysis software "CPMA" manufactured by Kanto Electronic Application Development Co., Ltd. on a PC connected to the network analyzer, the dielectric loss tangent (tanδ) at 20 °C and 6 GHz was determined.

[0162]

Table 4

Claims

1. containing tetrafluoroethylene units, perfluoro(propyl vinyl ether) units, and monomer units derived from monomers copolymerizable with tetrafluoroethylene and perfluoro(propyl vinyl ether), the content of perfluoro(propyl vinyl ether) units being 2.26 to 2.75 mol% based on all monomer units, the content of tetrafluoroethylene units being 97.25 to 97.74 mol% based on all monomer units, the content of monomer units derived from monomers copolymerizable with tetrafluoroethylene and perfluoro(propyl vinyl ether) being 0 to 0.20 mol% based on all monomer units, the melt flow rate at 372 °C being 4.0 to 11.0 g / 10 min, The number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH is 50 or less per 10 main chain carbon atoms ６ each a copolymer.

2. The copolymer according to Claim 1, wherein the melt flow rate at 372 °C is 5.0 to 10.0 g / 10 min.

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

4. A coated electric wire comprising a coating layer containing the copolymer according to Claim 1 or 2.

5. A molded article containing the copolymer according to Claim 1 or 2, wherein the molded article is a filter housing, a film, a bottle, an electric wire coating, or a tube.

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