Copolymers, molded articles, injection-molded articles, and insulated wires

Abstract

Provided is a copolymer from which a beautiful injection-molded article can be obtained by injection molding, which is resistant to corrosion of the mold used in molding and the core wire to be coated, which can be used by extrusion molding to form a very thick coating layer of uniform thickness on a core wire with a very large diameter, and which has excellent abrasion resistance, low nitrogen permeability, low chemical solution permeability, low water vapor permeability, rigidity at a high temperature of 110°C, high-temperature tensile creep properties, resistance to deterioration under repeated loads, extremely long-term ozone resistance, sealing properties and non-stickiness at high temperatures, and which can also be used to obtain a molded article that is resistant to elution of fluorine ions into an electrolyte. The polymer contains tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, the content of perfluoro(propyl vinyl ether) units being 3.9 to 4.9 mass% based on the total amount of monomer units, the melt flow rate at 372°C being 4.0 to 9.0 g / 10 min, and the number of functional groups is 10 carbon atoms in the main chain. 6 The copolymer has a molecular weight of 40 or less per unit area.

Description

[Technical Field]

[0001] This disclosure relates to copolymers, molded articles, injection-molded articles, and insulated wires. [Background technology]

[0002] Patent Document 1 describes a molding material for ozone-resistant articles comprising a copolymer (A) with 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, containing 3.5% by mass or more of perfluorovinyl ether units, having a melting point of 295°C or higher, and having unstable end groups with 1 × 10 carbon atoms in the copolymer (A). 6 A molding material for ozone-resistant articles is described, characterized in that it has 50 or fewer particles per unit.

[0003] Patent Document 2 contains carbon atom 10 6 The present invention describes a melt-extruded cube of a melt-processable TFE copolymer having approximately 80 or fewer unstable end groups per cube, characterized in that at least approximately 80% by weight of the cube has a size range of approximately 200 to approximately 1200 μm. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2003 / 048214 [Patent Document 2] Special Publication No. 2003-534940 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the present disclosure, a beautiful injection molded product can be obtained by injection molding, the mold used for molding and the core wire to be coated are less likely to be corroded, and 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 object is to provide a copolymer that has excellent abrasion resistance, low nitrogen permeability, low chemical liquid permeability, low water vapor permeability, rigidity at 110 °C, high-temperature tensile creep characteristics, resistance to deterioration under repeated loads, extremely long-term ozone resistance, sealing properties at high temperatures, and non-stick properties, and is also difficult to elute fluoride ions in an electrolytic solution.

Means for Solving the Problems

[0006] 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 3.9 to 4.9% by mass based on all monomer units, the melt flow rate at 372 °C is 4.0 to 9.0 g / 10 min, and the number of functional groups is 40 or less per 10 main-chain carbon atoms. 6 per copolymer is provided.

[0007] In the copolymer of the present disclosure, the melt flow rate at 372 °C is preferably 5.0 to 9.0 g / 10 min.

[0008] Further, according to the present disclosure, there is provided an injection molded product containing the above copolymer.

[0009] Further, according to the present disclosure, there is provided a coated electric wire provided with a coating layer containing the above copolymer.

[0010] Further, according to the present disclosure, there is provided a molded product containing the above copolymer, wherein the molded product is a joint, film, bottle, gasket, wire coating or tube.

Advantages of the Invention

[0011] According to this disclosure, it is possible to obtain a copolymer that can be molded by injection molding to obtain a beautiful injection-molded article, which is less likely to corrode the mold used for molding and the core wire to be coated, which can be formed by extrusion molding to form a very thick coating layer of uniform thickness on a very large diameter core wire, which has excellent abrasion resistance, low nitrogen permeability, low chemical permeability, low water vapor permeability, high temperature rigidity at 110°C, high temperature tensile creep characteristics, resistance to degradation under repeated loads, extremely long-term ozone resistance, high temperature sealing and non-stick properties, and which is less likely to leach fluoride ions into the electrolyte. [Modes for carrying out the invention]

[0012] The following describes specific embodiments of this disclosure in detail, but this disclosure is not limited to the embodiments described below.

[0013] The copolymers of this disclosure contain tetrafluoroethylene (TFE) units and perfluoro(propyl vinyl ether) (PPVE) units.

[0014] Copolymers (PFAs) containing TFE and PPVE units are used as materials for forming piping components used to transport fluids, such as pipes, fittings, gaskets, and packings. PFA piping components are used, for example, to transport fluids at temperatures exceeding 100°C, or to transport chemicals where contamination by moisture such as water vapor from the outside air is undesirable. Therefore, there is a need for materials that can produce molded articles with excellent low permeability to chemicals, high-temperature rigidity, high-temperature tensile creep characteristics, high-temperature sealing properties, and low water vapor permeability. Furthermore, since fittings are prone to damage due to wear when repeatedly attached and detached, there is a need for materials that can produce molded articles with excellent resistance to degradation and wear against repeated loads.

[0015] Patent Document 1 describes a molding material for ozone-resistant articles having the above-mentioned characteristics, which is a molding material with excellent ozone resistance while maintaining the chemical resistance, heat resistance, and mechanical properties of fluororesin. In recent years, there has been a demand for molding materials with improved properties compared to the molding material for ozone-resistant articles described in Patent Document 1, and in particular, there is a demand for materials that can produce molded articles with improved abrasion resistance, low nitrogen permeability, low chemical permeability, high-temperature rigidity, high-temperature tensile creep characteristics, resistance to degradation under repeated loads, extremely long-term ozone resistance, high-temperature sealing performance, and low water vapor permeability. On the other hand, when trying to improve high-temperature sealing performance and low water vapor permeability, there is a problem that abrasion resistance and ozone resistance may be reduced.

[0016] It was found that by appropriately adjusting the PPVE unit content, melt flow rate (MFR), and number of functional groups of copolymers containing TFE units and PPVE units, the moldability of the copolymer was significantly improved, and at the same time, it became less corrosive to the molds used for molding. Furthermore, it was also found that by using such copolymers, molded articles could be obtained that exhibited excellent abrasion resistance, low nitrogen permeability, low chemical permeability, low water vapor permeability, high temperature rigidity at 110°C, high temperature tensile creep characteristics, resistance to degradation under repeated loads, extremely long-term ozone resistance, high temperature sealing properties, and non-stick properties, as well as being less likely to leach fluoride ions into the electrolyte.

[0017] Furthermore, by molding the copolymer of this disclosure by extrusion molding, a very thick coating layer can be formed with a uniform thickness on a very large diameter core wire. Moreover, the resulting coating layer is resistant to corrosion of the core wire. Thus, the copolymer of this disclosure can be used not only as a material for piping components, but also for a wide range of applications such as wire coatings.

[0018] The copolymer of this disclosure is a melt-processable fluororesin. Melt-processability means that the polymer can be melted and processed using conventional processing equipment such as extruders and injection molding machines.

[0019] The PPVE unit content of the copolymer is 3.9 to 4.9% by mass relative to the total monomer units. Preferably, the PPVE unit content of the copolymer is 4.0% by mass or more, more preferably 4.1% by mass or more, preferably 4.8% by mass or less, more preferably 4.7% by mass or less, even more preferably 4.6% by mass or less, even more preferably 4.5% by mass or less, particularly preferably 4.4% by mass or less, and most preferably 4.3% by mass or less. If the PPVE unit content of the copolymer is too high, it will result in poor sealing performance at high temperatures, low water vapor permeability, low nitrogen permeability, low chemical permeability, and poor rigidity at high temperatures of 110°C. If the PPVE unit content of the copolymer is too low, it will be difficult to obtain a molded article with excellent degradation resistance to repeated loading and extremely long-term ozone resistance.

[0020] The TFE unit content of the copolymer is preferably 95.1 to 96.1% by mass, more preferably 95.2% by mass or more, even more preferably 95.3% by mass or more, still more preferably 95.4% by mass or more, especially more preferably 95.5% by mass or more, particularly preferably 95.6% by mass or more, most preferably 95.7% by mass or more, more preferably 96.0% by mass or less, and still more preferably 95.9% by mass or less, relative to the total monomer units. If the TFE unit content of the copolymer is too low, it may result in poor sealing performance at high temperatures, low water vapor permeability, low nitrogen permeability, low chemical permeability, and poor rigidity at high temperatures of 110°C. If the TFE unit content of the copolymer is too high, it tends to become difficult to obtain a molded article with excellent degradation resistance to repeated loading and extremely long-term ozone resistance.

[0021] In this disclosure, the content of each monomer unit in the copolymer is: 19 Measurement is performed using the 1F-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 1.2% by mass, more preferably 0.05 to 1.0% by mass, and even more preferably 0.1 to 0.7% by mass based on all the 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 (where 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 (where Rf 1 is a perfluoroalkyl group having 1 to 8 carbon atoms) perfluoro(alkyl vinyl ether) [PAVE] (excluding PPVE), and CF2=CF-OCH2-Rf 1 (where Rf 1 represents a perfluoroalkyl group having 1 to 5 carbon atoms). Examples include alkyl perfluorovinyl ether derivatives and the like. 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 9.0 g / 10 min. Preferably, the MFR of the copolymer is 4.1 g / 10 min or more, more preferably 4.5 g / 10 min or more, even more preferably 5.0 g / 10 min or more, particularly preferably 6.0 g / 10 min or more, most preferably 7.0 g / 10 min or more, preferably 8.0 g / 10 min or less, more preferably 7.5 g / 10 min or less, and even more preferably 7.4 g / 10 min or less. When the MFR of the copolymer is within the above range, the moldability of the copolymer is improved, and a molded article can be obtained that has excellent abrasion resistance, low nitrogen permeability, low chemical permeability, low water vapor permeability, high temperature rigidity at 110°C, high temperature tensile creep characteristics, resistance to degradation under repeated loads, extremely long-term ozone resistance, high temperature sealing properties, and non-stick properties. If the MFR is too high, it becomes difficult to obtain a molded article with excellent abrasion resistance and extremely long-term ozone resistance. If the MFR is too low, the molded product tends to have poor nitrogen permeability, poor chemical permeability, and poor rigidity at high temperatures of 110°C.

[0026] The copolymers of this disclosure, which contain TFE units and PPVE units, have their PPVE unit content, melt flow rate (MFR), and number of functional groups appropriately adjusted, so they can be molded by injection molding or by wire coating extrusion molding. Copolymers that flow sufficiently when heated are suitable for injection molding, while if a copolymer that is too fluid at high temperatures is used to form a wire coating layer by extrusion molding, the outer diameter may vary greatly. The copolymers of this disclosure can produce beautifully molded injection-molded articles even when molded by injection molding, and can produce coated wires with small variations in outer diameter even when molded by extrusion molding.

[0027] In this disclosure, MFR is a value obtained in accordance with ASTM D1238 as the mass (g / 10 min) of polymer flowing out of a nozzle with an inner diameter of 2.1 mm and a length of 8 mm per 10 minutes using a melt indexer at 372°C and a load of 5 kg.

[0028] MFR can be adjusted by adjusting the type and amount of polymerization initiator and chain transfer agent used when polymerizing monomers.

[0029] In this disclosure, the main chain number of the copolymer is 10 6 The number of functional groups per molecule is 40 or less. The main chain number of the copolymer is 10 6 The number of functional groups per unit is preferably 30 or less, more preferably 20 or less, even more preferably 15 or less, even more preferably 10 or less, and particularly preferably less than 6. Because the number of functional groups in the copolymer is within the above range, it is less likely to corrode the mold during molding using a mold, and less likely to corrode the core wire when used as a wire coating. Furthermore, it is possible to obtain a molded article that exhibits extremely long-term ozone resistance, low nitrogen permeability, low chemical permeability, rigidity and non-stickiness at high temperatures of 110°C, and is less likely to leach fluoride ions into the electrolyte. In particular, by appropriately adjusting the PPVE unit content, melt flow rate (MFR), and number of functional groups of a copolymer containing TFE units and PPVE units, it is possible to obtain a molded article that exhibits excellent low permeability to various chemicals such as dimethyl carbonate and ethyl acetate.

[0030] Infrared spectroscopy can be used to identify the types of functional groups and measure their number.

[0031] The number of functional groups is specifically measured by the following method. First, the 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 copolymer, and a difference spectrum is obtained from this spectrum to the base spectrum where the copolymer is completely fluorinated and no functional groups are present. From the absorption peak of a specific functional group appearing in this difference spectrum, the number of carbon atoms in the copolymer (1 × 10) is determined according to the following formula (A). 6 Calculate the number of functional units N per individual.

[0032] N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm)

[0033] For reference, Table 1 shows the absorption frequency, molar extinction coefficient, and correction factor for several functional groups. The molar extinction coefficient was determined from FT-IR measurement data of a small molecule model compound. [Table 1]

[0034] The absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are tens of kaiser (cm) from the absorption frequencies of -CF2H, -COF, -COOH free and -COOH bonded, -COOCH3, and -CONH2, respectively, as shown in the table. -1 ) It will become lower.

[0035] For example, the number of functional groups in -COF is the absorption frequency of 1883 cm⁻¹ due to -CF₂COF. -1 The number of functional groups determined from the absorption peak and the absorption frequency of 1840 cm² due to -CH2COF -1 This is the sum of the number of functional groups determined from the absorption peaks.

[0036] Functional groups are functional groups located at the ends of the main chain or side chains of the copolymer, and functional groups located within the main chain or side chains. The number of functional groups may be the total number of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH.

[0037] The functional groups described above are introduced into the copolymer, for example, by chain transfer agents or polymerization initiators used in the production of the copolymer. For instance, if an alcohol is used as a chain transfer agent, or if a peroxide having the structure -CH2OH is used as a polymerization initiator, -CH2OH is introduced to the main chain ends of the copolymer. Alternatively, the functional groups can be introduced to the side chain ends of the copolymer by polymerizing monomers having the functional groups.

[0038] By fluorinating a copolymer having such functional groups, a copolymer having a number of functional groups within the above range can be obtained. That is, it is preferable that the copolymer of this disclosure is fluorinated. It is also preferable that the copolymer of this disclosure has a -CF3 terminal group.

[0039] The melting point of the copolymer is preferably 295 to 315°C, more preferably 298°C or higher, even more preferably 300°C or higher, particularly preferably 301°C or higher, most preferably 302°C or higher, and more preferably 310°C or lower. Having the melting point within this range makes it possible to obtain a copolymer that provides a molded article with even better sealing properties, especially at high temperatures.

[0040] In this disclosure, the melting point can be measured using a differential scanning calorimetry (DSC).

[0041] The water vapor permeability of the copolymer is preferably 14.0 g·cm / m 2 The following, and more preferably 13.5 g·cm / m 2 The following, and more preferably 13.0 g·cm / m 2 The following applies: The copolymer of this disclosure has excellent low water vapor permeability because the content of PPVE units, melt flow rate (MFR), and number of functional groups of the copolymer containing TFE units and PPVE units are appropriately adjusted. Therefore, when a molded article containing the copolymer of this disclosure is used, for example, as a piping component (e.g., pipe, fittings, gaskets, packings) for supplying chemicals that are sensitive to moisture, the penetration of water vapor into the piping component can be suppressed, and the mixing of moisture into the chemicals can be suppressed. Furthermore, by using a molded article containing the copolymer of this disclosure, for example, as a compressible component of a secondary battery, the intrusion of moisture can be effectively prevented even under high temperature and high humidity conditions.

[0042] In this disclosure, water vapor transmission can be measured under conditions of 95°C for 30 days. Specific measurements of water vapor transmission can be performed by the method described in the examples.

[0043] The electrolyte permeability of the copolymer is preferably 7.9 g·cm / m 2 The following, and more preferably 7.7 g·cm / m 2 The following applies: The copolymer of this disclosure has excellent low electrolyte permeability because the content of PPVE units, melt flow rate (MFR), and number of functional groups of the copolymer containing TFE units and PPVE units are appropriately adjusted. In other words, by using the copolymer of this disclosure, it is possible to obtain molded articles that are less permeable to chemicals such as electrolytes, so for example, piping members and flow meter members obtained using the copolymer of this disclosure can be suitably used for transferring chemicals such as electrolytes.

[0044] In this disclosure, electrolyte permeability can be measured under conditions of 60°C for 30 days. Specific measurement of electrolyte permeability can be performed by the method described in the examples.

[0045] The permeability of the copolymer to ethyl acetate is preferably 7.0 g·cm / m 2 The following applies: The copolymer of this disclosure has excellent low permeability to ethyl acetate because the content of PPVE units, melt flow rate (MFR), and number of functional groups of the copolymer containing TFE units and PPVE units are appropriately adjusted. In other words, by using the copolymer of this disclosure, it is possible to obtain a molded article that is less permeable to chemical solutions such as ethyl acetate.

[0046] In this disclosure, the permeability of ethyl acetate can be measured under conditions of 60°C for 45 days. Specific measurements of the ethyl acetate permeability can be performed by the method described in the examples.

[0047] The nitrogen permeability coefficient of the copolymer is preferably 330 cm⁻¹. 3 ·mm / (m 2The nitrogen permeability is less than or equal to 24h·atm. The copolymer of this disclosure has excellent low nitrogen permeability because the content of PPVE units, melt flow rate (MFR), and number of functional groups of the copolymer containing TFE units and PPVE units are appropriately adjusted. Therefore, by using the copolymer of this disclosure, a molded article with excellent gas barrier properties can be obtained.

[0048] In this disclosure, the nitrogen 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 nitrogen permeability coefficient can be carried out by the method described in the examples.

[0049] The copolymer of this disclosure has an amount of eluted fluoride ions detected in an electrolyte immersion test that is preferably 1.0 ppm or less, more preferably 0.8 ppm or less, and even more preferably 0.7 ppm or less, on a mass basis. Having the amount of eluted fluoride ions within the above range can further suppress the generation of gases such as HF in non-aqueous electrolyte batteries, and further suppress the deterioration of battery performance and shortening of battery life of non-aqueous electrolyte batteries.

[0050] In this disclosure, the electrolyte immersion test can be performed by preparing a test piece using a copolymer with a weight equivalent 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 constant temperature bath at 80°C for 144 hours.

[0051] The storage modulus (E') of the copolymer at 150°C is preferably 70 MPa or higher, more preferably 75 MPa or higher, preferably 1000 MPa or lower, more preferably 500 MPa or lower, and even more preferably 300 MPa or lower. By having the storage modulus (E') of the copolymer at 150°C within the above range, sufficient rebound elasticity can be maintained for a long period even at high temperatures, resulting in a copolymer that provides a molded article with even better sealing properties at high temperatures.

[0052] The storage modulus (E') can be measured by dynamic viscoelasticity testing in the range of 30 to 250°C under conditions of a heating rate of 2°C / min and a frequency of 10 Hz. The storage modulus (E') at 150°C can be increased by adjusting the PPVE unit content and melt flow rate (MFR) of the copolymer.

[0053] The seal pressure of the copolymer at 150°C is preferably 0.45 MPa or higher, more preferably 0.50 MPa or higher, and even more preferably 0.55 MPa or higher. The upper limit is not particularly limited, but may be 3.00 MPa or lower. The seal pressure at 150°C can be increased by adjusting the PPVE unit content, melt flow rate (MFR), and number of functional groups of the copolymer.

[0054] The sealing pressure can be calculated by the following formula, using the height of the specimen (height of the specimen after compression deformation) and the storage modulus (MPa) at 150°C, after deforming the specimen obtained from the copolymer to a compression deformation rate of 50% and leaving it at 150°C for 18 hours, releasing the compression, leaving it at room temperature for 30 minutes, and then measuring the height of the specimen (height of the specimen after compression deformation). 150℃ seal pressure (MPa) = (t2-t1) / t1 × E' t1: Original height of the test specimen before compression deformation (mm) × 50% t2: Height of the test specimen after compression deformation (mm) E': Storage modulus at 150°C (MPa)

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

[0056] As polymerization initiators, oil-soluble radical polymerization initiators or water-soluble radical polymerization initiators can be used.

[0057] The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, for example, Dialkyl peroxycarbonates such as dinormal propyl peroxydicarbonate, diisopropyl peroxydicarbonate, disec-butyl peroxydicarbonate, and di-2-ethoxyethyl peroxydicarbonate; Peroxy esters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate; Dialkyl peroxides such as di-t-butyl peroxide; Di[fluoro(or fluorochloro)acyl]peroxides; These are some typical examples.

[0058] Examples of di[fluoro(or fluorochloro)acyl]peroxides include diacylperoxides represented as [(RfCOO)-]2 (where Rf is a perfluoroalkyl group, an ω-hydroperfluoroalkyl group, or a fluorochloroalkyl group).

[0059] Examples of di[fluoro(or fluorochloro)acyl]peroxides include di(ω-hydro-dodecafluorohexanoyl)peroxide, di(ω-hydro-tetradecafluoroheptanoyl)peroxide, di(ω-hydro-hexadecafluorononanoyl)peroxide, di(perfluoropropionyl)peroxide, di(perfluorobutyryl)peroxide, di(perfluoropareryl)peroxide, di(perfluorohexanoyl)peroxide, di(perfluoroheptanoyl)peroxide, di(perfluorooctanoyl)peroxide, di(perfluorononanoyl)peroxide, di(ω-chloro-hexafluorobutyryl)peroxide, and di(ω-chloro-decafluorohexa Examples include (noyl) peroxide, di(ω-chloro-tetradecafluorooctanoyl) peroxide, ω-hydro-dodecafluoroheptanoyl-ω-hydrohexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydrododecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl) peroxide, di(trichlorooctafluorohexanoyl) peroxide, di(tetrachloroundecafluorooctanoyl) peroxide, di(pentachlorotetradecafluorodecanoyl) peroxide, and di(undecachlorotriacontafluorodocosanoyl) peroxide.

[0060] The water-soluble radical polymerization initiator may be a known water-soluble peroxide, such as ammonium salts, potassium salts, and sodium salts of persulfuric acid, perboric acid, perchloric acid, superphosphate, and percarbonate; organic peroxides such as disuccinate peroxide and diglutaric acid peroxide; t-butyl permalate; and t-butyl hydroperoxide. A reducing agent such as sulfites may also be used in combination with the peroxide, and the amount used may be 0.1 to 20 times the amount of the peroxide.

[0061] In polymerization, surfactants, chain transfer agents, and solvents can be used, and conventionally known surfactants can be used for each of these.

[0062] As the surfactant, known surfactants can be used, such as nonionic surfactants, anionic surfactants, and cationic surfactants. Among these, fluorine-containing anionic surfactants are preferred, and linear or branched fluorine-containing anionic surfactants having 4 to 20 carbon atoms are more preferred, which may contain ether-bonded oxygen (i.e., oxygen atoms may be inserted between carbon atoms). The amount of surfactant added (relative to polymerization water) is preferably 50 to 5000 ppm.

[0063] 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; acetic acid 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 amount of chain transfer agent added may 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 relative to the polymerization solvent.

[0064] Examples of solvents include water and mixed solvents of water and alcohol.

[0065] In suspension polymerization, a fluorinated solvent may be used in addition to water. Examples of fluorinated solvents include hydrochlorofluoroalkanes such as CH3CClF2, CH3CCl2F, CF3CF2CCl2H, and CF2ClCF2CFHCl; chlorofluoroalkanes such as CF2ClCFClCF2CF3 and CF3CFClCFClCF3; hydrofluoroalkanes such as CF3CFHCFHCF2CF2CF3, CF2HCF2CF2CF2CF2H, and CF3CF2CF2CF2CF2CF2CF2H; and CH3OC2F5 and CH3OC3F5. Examples include hydrofluoroethers such as CF3CF2CH2OCHF2, CF3CHFCF2OCH3, CHF2CF2OCH2F, (CF3)2CHCF2OCH3, CF3CF2CH2OCH2CHF2, and CF3CHFCF2OCH2CF3; and perfluoroalkanes such as perfluorocyclobutane, CF3CF2CF2CF3, CF3CF2CF2CF2CF3, and CF3CF2CF2CF2CF2CF3, with perfluoroalkanes being preferred. The amount of fluorinated solvent used is preferably 10 to 100% by mass relative to the aqueous medium, from the standpoint of suspension and economy.

[0066] The polymerization temperature is not particularly limited and may be between 0 and 100°C. The polymerization pressure is determined appropriately depending on the type and amount of solvent used, its vapor pressure, the polymerization temperature, and other polymerization conditions, but is usually between 0 and 9.8 MPaG.

[0067] If the polymerization reaction yields an aqueous dispersion containing the copolymer, the copolymer can be recovered by coagulating, washing, and drying the copolymer contained in the aqueous dispersion. Alternatively, if the polymerization reaction yields the copolymer as a slurry, the copolymer can be recovered by removing the slurry from the reaction vessel, washing, and drying it. Drying allows the copolymer to be recovered in powder form.

[0068] The copolymer obtained by polymerization may be formed into pellets. There are no particular limitations on the molding method for forming pellets, and conventionally known methods can be used. For example, one method involves melt-extruding the copolymer using a single-screw extruder, twin-screw extruder, or tandem extruder, and then cutting it to a predetermined length to form pellets. The extrusion temperature during melt-extrusion needs to be varied depending on the melt viscosity of the copolymer and the manufacturing method, and is preferably between the melting point of the copolymer + 20°C and the melting point of the copolymer + 140°C. There are no particular limitations on the method of cutting the copolymer, and conventionally known methods such as strand cutting, hot cutting, underwater cutting, and sheet cutting can be used. The obtained pellets may be heated to remove volatile components (degassing treatment). The obtained pellets may also be treated by contacting them with hot water at 30-200°C, steam at 100-200°C, or hot air at 40-200°C.

[0069] The copolymer obtained by polymerization may be subjected to fluorination treatment. Fluorination treatment can be carried out by contacting an unfluorinated copolymer with a fluorine-containing compound. Fluorination treatment can convert thermally unstable functional groups such as -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, and -CONH2, as well as thermally relatively stable functional groups such as -CF2H, into the thermally extremely stable -CF3. As a result, the total number of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, and -CF2H (number of functional groups) in the copolymer can be easily adjusted to the range described above.

[0070] 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 fluorine radical sources include F2 gas, CoF3, AgF2, UF6, OF2, N2F2, CF3OF, and halogenated fluorides (e.g., IF5, ClF3).

[0071] Fluorine radical sources such as F2 gas may be at 100% concentration, but for safety reasons, it is preferable to mix them with an inert gas and dilute them to 5-50% by mass, and more preferably to 15-30% by mass. Examples of the inert gas include nitrogen gas, helium gas, and argon gas, but nitrogen gas is preferred for economic reasons.

[0072] The conditions for the fluorination treatment are not particularly limited, and the copolymer may be brought into contact with a fluorine-containing compound in a molten state. However, it is usually carried out at a temperature below the melting point of the copolymer, preferably 20 to 240°C, and more preferably 100 to 220°C. The above 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 unfluorinated copolymer into contact with fluorine gas (F2 gas).

[0073] A composition may be obtained by mixing the copolymer of the present disclosure with other components as needed. 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, softeners, and hydrofluoricating agents.

[0074] Examples of fillers include silica, kaolin, clay, organic clay, 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 fibers. 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 fluorine-based aids. Examples of dehydrofluoridating agents include organonium and amidines.

[0075] Other polymers besides the copolymers described above may be used as the other components. Examples of other polymers include fluororesins, fluororubbers, and non-fluorinated polymers other than the copolymers described above.

[0076] Examples of methods for producing the above composition include a method of dry mixing the copolymer and other components, or a method of pre-mixing the copolymer and other components in a mixer and then melt-kneading them in a kneader, melt extruder, etc.

[0077] The copolymers or compositions described herein can be used as processing aids, molding materials, etc., but are preferably used as molding materials. Aqueous dispersions, solutions, suspensions, and copolymer / solvent systems of the copolymers described herein are also available and can be applied as coatings, or used for sealing, impregnation, and film casting. However, since the copolymers described herein have the properties described above, they are preferably used as molding materials.

[0078] A molded article may be obtained by molding the copolymer of the present disclosure or the above composition.

[0079] The method for molding the above copolymer or composition is not particularly limited and includes injection molding, extrusion molding, compression molding, blow molding, transfer molding, roto molding, roto lining molding, etc. Among the molding methods, extrusion molding, compression molding, injection molding, or transfer molding are preferred, and injection molding, extrusion molding, or transfer molding are more preferred, with injection molding being even more preferred, as they allow for the production of molded articles with high productivity. In other words, the molded article is preferably an extruded article, a compressed article, an injection-molded article, or a transfer-molded article, and is more preferably an injection-molded article, with injection molding being even more preferred, as they allow for the production of molded articles with high productivity. By molding the copolymer of this disclosure by injection molding, an injection-molded article with a beautiful appearance can be obtained without corroding the mold used for molding.

[0080] Examples of molded articles containing the copolymer of this disclosure include nuts, bolts, fittings, films, bottles, gaskets, wire insulation, tubes, hoses, pipes, valves, seats, seals, packings, tanks, rollers, containers, cocks, connectors, filter housings, filter cages, flow meters, pumps, wafer carriers, wafer boxes, and the like.

[0081] The copolymers, compositions, or molded articles of this disclosure can be used, for example, in the following applications: Food packaging films, lining materials for fluid transfer lines used in food manufacturing processes, packings, sealing materials, sheets, and other fluid transfer components for food manufacturing equipment; Chemical stoppers, packaging films, lining materials, packings, sealing materials, sheets, and other chemical liquid transfer components used in pharmaceutical manufacturing processes; Internal lining material for chemical tanks and piping in chemical plants and semiconductor factories; O-rings, tubes, gaskets, valve cores, hoses, seals, etc. used in the fuel systems and peripheral equipment of automobiles; fuel transfer components such as hoses and seals used in the automatic transmission systems of automobiles; Carburetor flange gaskets, shaft seals, valve stem seals, sealing materials, hoses, etc. used in automobile engines and peripheral equipment; other automotive components such as automobile brake hoses, air conditioning hoses, radiator hoses, and wire insulation materials; Chemical transfer components for semiconductor equipment, such as O-rings, tubes, packings, valve cores, hoses, sealing materials, rolls, gaskets, diaphragms, and fittings for semiconductor manufacturing equipment; Painting and ink-related components for painting equipment, such as paint rolls, hoses, tubes, and ink containers; Tubes or hoses for food and beverages, belts, gaskets, fittings and other components for transporting food and beverages, food packaging materials, glass cooking equipment; Tubes, hoses, and other components for transporting waste liquids; Components for transporting high-temperature liquids, such as tubes and hoses; Steam piping components such as tubes and hoses for steam piping; Corrosion-preventive tapes for pipes, such as tapes used to wrap around pipes on ship decks; Various coating materials such as wire coatings, optical fiber coatings, transparent surface coatings and backing materials for the light incident side surface of photovoltaic elements in solar cells; Sliding components of diaphragm pumps, such as diaphragms and various packings; Agricultural films, weather-resistant covers for various roofing materials and side walls; Interior materials used in the construction field, and coatings for glass such as non-combustible fire-resistant safety glass; Lining materials such as laminated steel sheets used in the home appliance sector;

[0082] Other fuel transfer components used in the fuel system of the above-mentioned automobile include fuel hoses, filler hoses, and evaporator hoses. These fuel transfer components can also be used as fuel transfer components for sour-resistant gasoline, alcohol-resistant fuels, and fuels containing gasoline additives such as methyl tert-butyl ether and amines.

[0083] The chemical stoppers and packaging films for the above-mentioned chemicals have excellent chemical resistance to acids and other substances. Furthermore, corrosion-resistant tapes wrapped around chemical plant piping can also be used as chemical liquid transfer components.

[0084] Examples of the above-mentioned molded products include automobile radiator tanks, chemical tanks, bellows, spacers, rollers, gasoline tanks, waste liquid transport containers, high-temperature liquid transport containers, and fishing and aquaculture tanks.

[0085] The above-mentioned molded products also include components used in automobiles such as bumpers, door trims, instrument panels, food processing equipment, cooking equipment, water- and oil-repellent glass, lighting-related equipment, display panels and housings for office automation equipment, illuminated signs, displays, liquid crystal displays, mobile phones, printed circuit boards, electrical and electronic components, general merchandise, trash cans, bathtubs, unit baths, ventilation fans, and lighting frames.

[0086] Molded articles containing the copolymer of this disclosure have excellent wear resistance, low nitrogen permeability, low chemical permeability, low water vapor permeability, high temperature rigidity at 110°C, high temperature tensile creep characteristics, resistance to degradation under repeated loads, extremely long-term ozone resistance, high temperature sealing properties, and non-stick properties, making them suitable for use in nuts, bolts, fittings, packings, valves, cocks, connectors, filter housings, filter cages, flow meters, pumps, and the like.

[0087] Molded articles containing the copolymer of this disclosure can be easily manufactured by injection molding without corroding the mold, and exhibit excellent wear resistance, low nitrogen permeability, low chemical permeability, low water vapor permeability, high temperature rigidity at 110°C, high temperature tensile creep characteristics, resistance to degradation under repeated loads, extremely long-term ozone resistance, high temperature sealing performance, and non-stick properties. Furthermore, they do not easily leach fluoride ions into the electrolyte, making them suitable for use as compressible members such as gaskets and packings. The compressible member of this disclosure may be a gasket or packing. The gasket or packing of this disclosure can be manufactured at low cost by injection molding without corroding the mold, is resistant to damage even when installed in locations that are opened and closed frequently, and exhibits excellent high temperature sealing performance, low nitrogen permeability, low chemical permeability, and low water vapor permeability. The compressible member of this disclosure is suitable for use as a piping member for transporting chemicals that are undesirable to be mixed with moisture such as water vapor from the outside air, due to its excellent abrasion resistance, low chemical permeability, extremely long-term ozone resistance, high-temperature sealing performance, and low water vapor permeability.

[0088] The compressible member of this disclosure exhibits high sealing pressure even when deformed at a high compression deformation rate. The compressible member of this disclosure can be used in a state of compression deformation at a compression deformation rate of 10% or more, and can be used in a state of compression deformation at a compression deformation rate of 20% or more or 25% or more. By using the compressible member of this disclosure in a state of deformation at such a high compression deformation rate, a certain rebound elasticity can be maintained for a long period of time, and sealing characteristics and insulation characteristics can be maintained for a long period of time.

[0089] The compressible member of this disclosure exhibits a high storage modulus, high recovery amount, and high sealing pressure even when deformed at high temperatures and with a high compression deformation rate. The compressible member of this disclosure can be used at temperatures above 150°C with a compression deformation rate of 10% or more, and can be used at temperatures above 150°C with a compression deformation rate of 20% or more or 25% or more. By using the compressible member of this disclosure deformed at such high temperatures and with a high compression deformation rate, a certain rebound elasticity can be maintained for a long period of time even at high temperatures, and sealing and insulating properties at high temperatures can be maintained for a long period of time.

[0090] The above compression deformation rate is the compression deformation rate of the part with the greatest compression deformation rate when the compressed member is used in a compressed state. For example, if a flattened member is used in a compressed state in the thickness direction, it is the compression deformation rate in the thickness direction. Also, for example, if only a part of the member is used in a compressed state, it is the compression deformation rate of the part with the greatest compression deformation rate among the compressed parts.

[0091] The size and shape of the compressible member of this disclosure may be set as appropriate depending on the application and are not particularly limited. The shape of the compressible member of this disclosure may be, for example, annular. Furthermore, the compressible member of this disclosure may have a circular, oval, or rounded-corner quadrilateral shape in plan view and have a through hole in its center.

[0092] The compressible member of this disclosure is preferably used as a piping member for circulating chemical solutions such as ozonated water. The compressible member of this disclosure is particularly suitable as a member used in contact with ozonated water because it has excellent long-term ozone resistance, high-temperature sealing properties, abrasion resistance, low chemical permeability, and low water vapor permeability. That is, the compressible member of this disclosure may have a liquid-contacting surface with ozonated water.

[0093] The compressible member of this disclosure is preferably used as a component for constituting a non-aqueous electrolyte battery. The compressible member of this disclosure has excellent abrasion resistance, low chemical permeability, and low water vapor permeability, as well as excellent sealing properties at high temperatures, rigidity at 110°C, high-temperature tensile creep characteristics, and resistance to degradation under repeated loads, and is less likely to dissolve fluoride ions into the electrolyte, making it particularly suitable as a component used in contact with the non-aqueous electrolyte in a non-aqueous electrolyte battery. That is, the compressible member of this disclosure may have a liquid-contacting surface with the non-aqueous electrolyte in a non-aqueous electrolyte battery.

[0094] The compressible member of this disclosure does not easily dissolve fluoride ions into the non-aqueous electrolyte. Therefore, by using the compressible member of this disclosure, it is possible to suppress the increase in fluoride ion concentration in the non-aqueous electrolyte. As a result, by using the compressible member of this disclosure, it is possible to suppress the generation of gases such as HF in non-aqueous electrolyte batteries, and to suppress the deterioration of battery performance and shortening of the lifespan of non-aqueous electrolyte batteries.

[0095] The compressible member of this disclosure can further suppress the generation of gases such as HF in non-aqueous electrolyte batteries, and can further suppress the deterioration of battery performance and shortening of battery life of non-aqueous electrolyte batteries. Therefore, 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 by mass. The electrolyte immersion test can be performed by preparing a test piece with a weight equivalent to 10 molded bodies (15 mm × 15 mm × 0.2 mm) using the compressible member, and placing a glass sample bottle containing the test piece and 2 g of dimethyl carbonate (DMC) in a constant temperature bath at 80°C for 144 hours.

[0096] The compressible member of this disclosure is impermeable to water vapor. Therefore, by using the compressible member of this disclosure, it is possible to suppress the permeation of water vapor into the secondary battery from the outside. As a result, by using the compressible member of this disclosure, it is possible to suppress the deterioration of the battery performance and shortening of the lifespan of a non-aqueous electrolyte battery.

[0097] The water vapor permeability of the compressible member in this disclosure is preferably 14.0 g·cm / m², as this can further suppress the deterioration of battery performance and shortening of the battery life of non-aqueous electrolyte batteries. 2 The following, and more preferably 13.5 g·cm / m 2 The following, and more preferably 13.0 g·cm / m 2 The following applies: The water vapor permeability of the compressible member can be measured under conditions of 95°C for 30 days. The copolymer of this disclosure has excellent low water vapor permeability because the content of PPVE units, melt flow rate (MFR), and number of functional groups of the copolymer containing TFE units and PPVE units are appropriately adjusted. Therefore, when a molded article containing the copolymer of this disclosure is used, for example, as a piping member (e.g., packing, gasket) for supplying ozonated water, the penetration of water vapor into the piping member can be suppressed, and therefore the amount of ozone that penetrates into the piping member along with the water vapor can also be reduced, so that the excellent ozone resistance of the piping member can be maintained for a long period of time.

[0098] Non-aqueous electrolyte batteries are not particularly limited as long as they contain a non-aqueous electrolyte, and examples include lithium-ion secondary batteries and lithium-ion capacitors. Furthermore, components constituting a non-aqueous electrolyte battery include sealing members and insulating members.

[0099] The above non-aqueous electrolyte is not particularly limited, but one or more known solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ-butyl lactone, 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.

[0100] The compressible members of this disclosure can be suitably used, for example, as sealing members such as sealing gaskets and sealing packings, and insulating members such as insulating gaskets and insulating packings. Sealing members are members used to prevent leakage of liquid or gas or intrusion of liquid or gas from the outside. Insulating members are members used to insulate electricity. The compressible members of this disclosure may be members used for both sealing and insulating purposes.

[0101] The compressible member of this disclosure has excellent heat resistance and excellent sealing properties at high temperatures, making it suitable for use in high-temperature environments. For example, the compressible member of this disclosure is suitable for use in environments where the maximum temperature is 40°C or higher. For example, the compressible member of this disclosure is suitable for use in environments where the maximum temperature is 150°C or higher. Situations in which the compressible member of this disclosure may reach such high temperatures include, for example, when the compressible member is attached to a battery in a compressed state and then other battery components are attached to the battery by welding, or when a non-aqueous electrolyte battery generates heat.

[0102] The compressible member of this disclosure exhibits excellent low water vapor permeability, excellent sealing properties at high temperatures, and is less likely to dissolve fluoride ions into the electrolyte, making it suitable for use as a sealing member or insulating member for non-aqueous electrolyte batteries. For example, during charging of batteries such as non-aqueous electrolyte secondary batteries, the battery temperature may temporarily exceed 40°C, and especially temporarily exceed 150°C. The compressible member of this disclosure maintains its high rebound elasticity even when used in batteries such as non-aqueous electrolyte secondary batteries, deformed at high temperatures with a high compression deformation rate, and even when in contact with the non-aqueous electrolyte at high temperatures. Therefore, when the compressible member of this disclosure is used as a sealing member, it has excellent sealing properties, and these sealing properties are maintained for a long period of time even at high temperatures. Furthermore, because the compressible member of this disclosure contains the above copolymer, it has excellent insulating properties. Therefore, when the compressible member of this disclosure is used as an insulating member, it adheres firmly to two or more conductive members, preventing short circuits for a long period of time.

[0103] The copolymer of this disclosure is less likely to corrode the core wire it covers. Furthermore, by molding the copolymer of this disclosure by extrusion molding, a very thick coating layer can be formed with a uniform thickness on a core wire with a very large diameter, making it suitable for use as a material for forming wire coatings. Therefore, a coated wire equipped with a coating layer containing the copolymer of this disclosure has excellent electrical properties because the core wire is less likely to corrode and the outer diameter hardly changes.

[0104] When attempting to form a very thick coating layer of uniform thickness on a very large diameter core wire, it takes time for the molten coating layer to solidify, and the coating layer is also heavy. Therefore, when using conventional copolymers, the coating layer deforms under its own weight before it solidifies, making it difficult to form a coating layer of uniform thickness. By using the copolymer of this disclosure, it is possible to form a very thick coating layer of uniform thickness.

[0105] The insulated wire comprises a core wire and a coating layer provided around the core wire and containing the copolymer of the present disclosure. For example, the coating layer can be an extruded body obtained by melt-extruding the copolymer of the present disclosure onto the core wire. The insulated wire is suitable for high-frequency transmission cables, flat cables, heat-resistant cables, etc., and is particularly suitable for high-frequency transmission cables.

[0106] For the core wire material, metal conductor materials such as copper and aluminum can be used. The core wire is preferably 0.02 to 3 mm in diameter. The core wire diameter is more preferably 0.04 mm or more, even more preferably 0.05 mm or more, and particularly preferably 0.1 mm or more. The core wire diameter is more preferably 2 mm or less.

[0107] Specific examples of core wires include, for instance, AWG-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.

[0108] The thickness of the coating layer is preferably 0.1 to 3.0 mm. A thickness of 2.0 mm or less is also preferable.

[0109] Examples of high-frequency transmission cables include coaxial cables. Coaxial cables generally have 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 to the outer periphery. The molded article containing the copolymer of this disclosure can be suitably used as an insulating coating layer containing the copolymer. The thickness of each layer in the above structure is not particularly limited, but typically 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.

[0110] The coating layer may contain air bubbles, and it is preferable that the air bubbles are uniformly distributed within the coating layer.

[0111] 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, and more preferably 1 μm or more. The average bubble diameter can be determined by taking an electron microscope image of the wire cross-section, calculating the diameter of each bubble through image processing, and averaging the results.

[0112] The coating layer may have a foaming rate of 20% or more. More preferably 30% or more, even more preferably 33% or more, and even more preferably 35% or more. There is no particular upper limit, but for example, it is 80%. The upper limit of the foaming rate may be 60%. The foaming rate is calculated as ((specific gravity of the wire coating material - specific gravity of the coating layer) / specific gravity of the wire coating material) × 100. The foaming rate can be appropriately adjusted according to the application, for example by adjusting the amount of gas inserted into the extruder as described later, or by selecting the type of gas to dissolve.

[0113] The insulated wire may have another layer between the core wire and the insulated layer, and may have yet another layer (outer layer) around the insulated layer. If the insulated layer contains air bubbles, the wire of this disclosure may have a two-layer structure (skin-foam) with a non-foamed layer inserted between the core wire and the insulated layer, a two-layer structure (foam-skin) with a non-foamed layer covering the outer layer, or 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 TFE / HFP copolymer, TFE / PAVE copolymer, TFE / ethylene copolymer, vinylidene fluoride polymer, polyolefin resin such as polyethylene [PE], or resin such as polyvinyl chloride [PVC].

[0114] Insulated wires can be manufactured, for example, by using an extruder to heat a copolymer, extrude the molten copolymer onto a core wire, and form an insulated layer.

[0115] In forming the coating layer, the copolymer can be heated, and while the copolymer is molten, a gas can be introduced into the copolymer to form a coating layer containing bubbles. Examples of gases that can be used include chlorodifluoromethane, nitrogen, carbon dioxide, or mixtures thereof. The gas may be introduced as a pressurized gas into the heated copolymer, or it may be generated by mixing a chemical blowing agent into the copolymer. The gas dissolves in the molten copolymer.

[0116] Furthermore, the copolymers of this disclosure can be suitably used as materials for products for high-frequency signal transmission.

[0117] The above-mentioned high-frequency signal transmission products are not particularly limited as long as they are products used for transmitting high-frequency signals, and include (1) molded boards such as insulating boards for high-frequency circuits, insulating materials for connecting components, and printed circuit boards, (2) molded bodies such as bases for high-frequency vacuum tubes and antenna covers, and (3) insulated wires such as coaxial cables and LAN cables. The above-mentioned high-frequency signal transmission products can be suitably used in equipment that utilizes microwaves, particularly microwaves in the 3 to 30 GHz range, such as satellite communication equipment and mobile phone base stations.

[0118] In the above-mentioned high-frequency signal transmission product, the copolymer of this disclosure can be suitably used as an insulator due to its low dielectric loss tangent.

[0119] As the molded plate in (1) above, a printed circuit board is preferred because it provides good electrical characteristics. The printed circuit board is not particularly limited, but examples include printed circuit boards for electronic circuits in mobile phones, various computers, communication equipment, etc. As the molded body in (2) above, an antenna cover is preferred because it has low dielectric loss.

[0120] The copolymer of this disclosure can be molded by injection molding to obtain a beautiful sheet. Furthermore, molded articles containing the copolymer of this disclosure exhibit excellent low nitrogen permeability, low chemical permeability, low water vapor permeability, and non-stick properties. Therefore, molded articles containing the copolymer of this disclosure can be suitably used as films or sheets.

[0121] The film disclosed herein has particularly excellent non-adhesion properties. Therefore, even when the film disclosed herein is heat-pressed with a resin such as epoxy resin, toner, etc., the two will not adhere to each other, and the resin, toner, etc. can be peeled off the film.

[0122] The film of this disclosure is useful as a release film. The release film can be manufactured by molding the copolymer of this disclosure by melt extrusion, calendering, press molding, casting, etc. From the viewpoint of obtaining a uniform thin film, the release film can be manufactured by melt extrusion.

[0123] The film of this disclosure can be applied to the surface of rolls used in office automation equipment. Furthermore, the copolymer of this disclosure can be formed into the required shape by extrusion molding, compression molding, press molding, etc., to form sheets, films, or tubes, and used as a surface material for office automation equipment rolls or belts. In particular, thin-walled tubes and films can be manufactured by melt extrusion molding.

[0124] Molded articles containing the copolymer of this disclosure exhibit excellent abrasion resistance, low nitrogen permeability, low chemical permeability, low water vapor permeability, high temperature rigidity at 110°C, high-temperature tensile creep characteristics, resistance to degradation under repeated loads, extremely long-term ozone resistance, high-temperature sealing properties, and non-stick properties, and are less likely to leach fluoride ions into the electrolyte, making them suitable for use as bottles or tubes.

[0125] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. [Examples]

[0126] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to such embodiments.

[0127] Each value in the examples was measured by the following method.

[0128] (Content in monomer units) The content of each monomer unit was measured using an NMR analyzer (e.g., Bruker BioSpin AVANCE300 high-temperature probe).

[0129] (Melt Flow Rate (MFR)) In accordance with ASTM D1238, the mass (g / 10 min) of polymer flowing out of a nozzle with an inner diameter of 2.1 mm and a length of 8 mm per 10 minutes was determined using a melt indexer G-01 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 372°C under a 5 kg load.

[0130] (Number of functional groups) Copolymer pellets were molded by cold pressing to produce films with a thickness of 0.25-0.30 mm. These films were scanned 40 times using a Fourier transform infrared spectrometer (FT-IR, Spectrum One, PerkinElmer) to obtain infrared absorption spectra, and the difference spectrum from the base spectrum, which is completely fluorinated and lacks functional groups, was obtained. From the absorption peaks of specific functional groups appearing in this difference spectrum, the carbon atoms in the sample (1 × 10⁶) were analyzed according to the following formula (A). 6 The number of functional cards N per individual was calculated. N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm) For reference, Table 2 shows the absorption frequency, molar extinction coefficient, and correction factor for the functional groups in this disclosure. The molar extinction coefficient was determined from FT-IR measurement data of a small molecule model compound.

[0131] [Table 2]

[0132] (Melting point) Using a differential scanning calorimeter (product name: X-DSC7000, manufactured by Hitachi High-Tech Science Corporation), the temperature was increased from 200°C to 350°C at a heating rate of 10°C / min, followed by cooling 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, and the melting point was determined from the melting curve peak generated during the second heating process.

[0133] Example 1 26.6 L of pure water was added to a 174 L autoclave, and after thorough nitrogen purging, 30.4 kg of perfluorocyclobutane, 1.21 kg of perfluoro(propyl vinyl ether) (PPVE), and 0.26 kg of methanol were charged, and the system temperature was maintained at 35°C and the stirring speed at 200 rpm. Next, tetrafluoroethylene (TFE) was injected under pressure to 0.58 MPa, and then 0.010 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was added to start polymerization. As polymerization progressed, the system pressure decreased, so TFE was continuously supplied to keep the pressure constant, and 0.043 kg of PPVE was added for every 1 kg of TFE supplied, and polymerization was continued for 6 hours. After releasing the TFE and returning the autoclave to atmospheric pressure, the resulting reaction product was washed with water and dried to obtain 15 kg of powder.

[0134] The obtained powder was melt-extruded at 360°C using a screw extruder (product name: PCM46, manufactured by Ikegai Co., Ltd.) to obtain TFE / PPVE copolymer pellets. The PPVE content of the obtained pellets was measured using the method described above. The results are shown in Table 3.

[0135] The obtained pellets were placed in a vacuum vibration reactor VVD-30 (manufactured by Okawara Seisakusho Co., Ltd.) and heated to 210°C. After vacuuming, F2 gas diluted to 20% by volume with N2 gas was introduced to atmospheric pressure. 0.5 hours after the introduction of F2 gas, the reactor was vacuumed and F2 gas was introduced again. After another 0.5 hours, the reactor was vacuumed again and F2 gas was introduced again. Thereafter, the above operations of introducing F2 gas and vacuuming were continued once every hour, and the reaction was carried out at a temperature of 210°C for 10 hours. After the reaction was completed, the reactor was thoroughly replaced with N2 gas to terminate the fluorination reaction. Various physical properties were measured using the fluorinated pellets by the method described above. The results are shown in Table 3.

[0136] Example 2 Fluorinated pellets were obtained in the same manner as in Example 1, except that 1.32 kg of PPVE was used, 0.31 kg of methanol was used, 0.046 kg of PPVE was added for every 1 kg of TFE supplied, the polymerization time was changed to 6.5 hours, the heating temperature of the vacuum vibrating reactor was changed to 170°C, and the reaction was carried out for 5 hours at a temperature of 170°C. The results are shown in Table 3.

[0137] Example 3 Fluorinated pellets were obtained in the same manner as in Example 1, except that 1.40 kg of PPVE was used, 0.31 kg of methanol was used, 0.048 kg of PPVE was added for every 1 kg of TFE supplied, and the polymerization time was changed to 6.5 hours. The results are shown in Table 3.

[0138] Example 4 Fluorinated pellets were obtained in the same manner as in Example 1, except that 1.48 kg of PPVE was used, 0.35 kg of methanol was used, 0.050 kg of PPVE was added for every 1 kg of TFE supplied, and the polymerization time was changed to 6.5 hours. The results are shown in Table 3.

[0139] Comparative Example 1 Fluorinated pellets were obtained in the same manner as in Example 1, except that 0.97 kg of PPVE and 0.37 kg of methanol were used, and 0.036 kg of PPVE was added for every 1 kg of TFE supplied. The results are shown in Table 3.

[0140] Comparative Example 2 Fluorinated pellets were obtained in the same manner as in Example 1, except that 1.05 kg of PPVE was used, 0.29 kg of methanol was used, 0.038 kg of PPVE was added for every 1 kg of TFE supplied, and the polymerization time was changed to 5.5 hours. The results are shown in Table 3.

[0141] Comparative Example 3 Fluorinated pellets were obtained in the same manner as in Example 1, except that 1.32 kg of PPVE and 0.10 kg of methanol were used, and 0.046 kg of PPVE was added for every 1 kg of TFE supplied. The results are shown in Table 3.

[0142] Comparative Example 4 51.8 L of pure water was added to a 174 L autoclave, and after thorough nitrogen purging, 40.9 kg of perfluorocyclobutane, 2.24 kg of perfluoro(propyl vinyl ether) (PPVE), and 1.85 kg of methanol were charged, and the system temperature was maintained at 35°C and the stirring speed at 200 rpm. Next, tetrafluoroethylene (TFE) was injected under pressure to 0.64 MPa, and then 0.051 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was added to start polymerization. As polymerization progressed, the system pressure decreased, so TFE was continuously supplied to keep the pressure constant, and 0.049 kg of PPVE was added for every 1 kg of TFE supplied. Polymerization was stopped when the amount of TFE added reached 40.9 kg. After releasing the unreacted TFE and returning the autoclave to atmospheric pressure, the resulting reaction product was washed with water and dried to obtain 41.0 kg of powder.

[0143] The obtained powder was melt-extruded in the same manner as in Example 1 to obtain unfluorinated pellets. The results are shown in Table 3.

[0144] Comparative Example 5 51.8 L of pure water was added to a 174 L autoclave, and after thorough nitrogen purging, 40.9 kg of perfluorocyclobutane, 1.85 kg of perfluoro(propyl vinyl ether) (PPVE), and 3.36 kg of methanol were charged, and the system temperature was maintained at 35°C and the stirring speed at 200 rpm. Next, tetrafluoroethylene (TFE) was injected under pressure to 0.64 MPa, and then 0.051 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was added to start polymerization. As polymerization progressed, the system pressure decreased, so TFE was continuously supplied to keep the pressure constant, and 0.043 kg of PPVE was added for every 1 kg of TFE supplied. Polymerization was stopped when the amount of TFE added reached 40.9 kg. After releasing the unreacted TFE and returning the autoclave to atmospheric pressure, the resulting reaction product was washed with water and dried to obtain 41.0 kg of powder.

[0145] The obtained powder was used to carry out a fluorination reaction in the same manner as in Example 1 to obtain fluorinated pellets. The results are shown in Table 3.

[0146] Comparative Example 6 Fluorinated pellets were obtained in the same manner as in Comparative Example 5, except that 2.53 kg of PPVE, 3.42 kg of methanol, 0.026 kg of a 50% methanol solution of di-n-propyl peroxydicarbonate, and an additional 0.055 kg of PPVE were added for every 1 kg of TFE supplied, resulting in 41.0 kg of dry powder. The results are shown in Table 3.

[0147] [Table 3]

[0148] In Table 3, the notation "<6" means that the number of functional groups is less than 6.

[0149] Next, the following characteristics were evaluated using the obtained pellets. The results are shown in Table 4.

[0150] (Storage modulus (E')) Dynamic viscoelasticity measurements were performed using a DVA-220 (manufactured by IT Measurement Control Co., Ltd.). As sample specimens, heat-pressed sheets measuring 25 mm in length, 5 mm in width, and 0.2 mm in thickness were used. Measurements were taken in the range of 30°C to 250°C under conditions of a heating rate of 2°C / min and a frequency of 10 Hz, and the storage modulus (MPa) at 150°C was read.

[0151] (Amount of restoration) The amount of restoration was measured according to the methods described in ASTM D395 or JIS K6262:2013.

[0152] Approximately 2g of the above pellets was placed in a mold (inner diameter 13mm, height 38mm), melted at 370°C for 30 minutes using a hot plate press, and then water-cooled under pressure of 0.2MPa (resin pressure) to produce a molded body with a height of approximately 8mm. Subsequently, a test specimen with an outer diameter of 13mm and a height of 6mm was prepared by cutting the obtained molded body. The prepared test specimen was compressed at room temperature using a compression device to a compression deformation rate of 50% (i.e., the test specimen with a height of 6mm was compressed to a height of 3mm). With the compressed test specimen still fixed in the compression device, it was left to stand in an electric furnace at 150°C for 18 hours. The compression device was removed from the electric furnace, cooled to room temperature, and the test specimen was removed. After leaving the recovered test specimen at room temperature for 30 minutes, the height of the recovered test specimen was measured, and the amount of restoration was calculated using the following formula. Restoration amount (mm) = t2 - t1 t1: Spacer height (mm) t2: Height of the test specimen removed from the compression device (mm) In the above test, t1 = 3 mm.

[0153] (Seal pressure at 150°C) Based on the results of the compression set test at 150°C and the storage modulus measurement at 150°C, the 150°C seal pressure was determined using the following formula. 150℃ seal pressure (MPa) = (t2-t1) / t1 × E' t1: Spacer height (mm) t2: Height of the test specimen removed from the compression device (mm) E': Storage modulus at 150°C (MPa)

[0154] (Water vapor transmission rate) Sheet-like test specimens with a thickness of approximately 0.2 mm were prepared using pellets and a heat press molding machine. (Test cup with a permeation area of ​​12.56 cm²) 2 18g of water was placed inside the container, covered with a sheet-like test piece, and sealed with a PTFE gasket. The sheet-like test piece was kept in contact with the water and maintained at 95°C for 30 days. After removal, it was left at room temperature for 2 hours and the mass loss was measured. The water vapor transmission rate (g·cm / m³) was calculated using the following formula. 2 ) was measured. Water vapor transmission rate (g·cm / m 2 ) = Mass loss (g) × Thickness of sheet-like test specimen (cm) / Permeation area (m²) 2 )

[0155] (Injection moldability) Copolymers were injection molded using an injection molding machine (Sumitomo Heavy Industries, Ltd., SE50EV-A) with a cylinder temperature of 395°C, a mold temperature of 220°C, and an injection speed of 3 mm / s. A mold made of HPM38 with chromium plating (100 mm × 100 mm × 3 mm thick, with a film gate and a flow length of 100 mm from the gate) was used as the mold. The obtained injection molded articles were observed and evaluated according to the following criteria. The presence or absence of cloudiness was confirmed by visual inspection. The presence or absence of surface roughness was confirmed by touching the surface of the injection molded article. 3: The entire injection-molded product is transparent, and the entire surface is smooth. 2: A cloudy appearance was observed within a 1 cm radius from where the mold gate was located, and the entire surface was smooth. 1: A cloudy appearance was observed within a 1 cm radius from where the mold gate was located, and surface roughness was confirmed within a 1 cm radius from where the mold gate was located. 0: The copolymer does not fill the entire mold, and a molded body of the desired shape cannot be obtained.

[0156] (Electrolyte immersion test) Approximately 5g of pellets were placed in a mold (inner diameter 120mm, height 38mm), melted at 370°C for 20 minutes using a hot plate press, and then water-cooled under pressure of 1MPa (resin pressure) to produce a molded body with a thickness of approximately 0.2mm. Subsequently, 15mm square test specimens were prepared using the obtained molded body.

[0157] Ten of the obtained test specimens and 2 g of dimethyl carbonate (DMC) were placed in a 20 mL glass sample bottle, and the bottle cap was closed. The sample bottle was placed in an 80°C constant temperature bath and left for 144 hours to immerse the test specimens in the DMC. After that, the sample bottle was removed from the constant temperature bath and allowed to cool to room temperature before the test specimens were removed from the sample bottle. The remaining DMC in the sample bottle was air-dried in a room controlled at 25°C for 24 hours, and 2 g of ultrapure water was added. The resulting aqueous solution was transferred to the measurement cell of an ion chromatography system, and the amount of fluoride ions in this aqueous solution was measured using an ion chromatography system (Thermo Fisher Scientific Dionex ICS-2100).

[0158] (Mold corrosion test) 20g of pellets were placed in a glass container (50ml screw-top tube), and a metal column (5mm square, 30mm long) made of HPM38 (Cr plating) or HPM38 (Ni plating) was suspended from the glass container so as not to touch the pellets. The glass container was then covered with aluminum foil. The glass container was placed in an oven in this state and heated at 380°C for 3 hours. After that, the heated glass container was removed from the oven and allowed to cool to room temperature, and the degree of corrosion on the surface of the metal column was visually observed. The degree of corrosion was judged according to the following criteria. ○: No corrosion observed △: Slight corrosion is observed. ×: Corrosion is observed.

[0159] (Wire insulation test) Using a 30mmφ wire coating molding machine (manufactured by Tanabe Plastic Machinery Co., Ltd.), a copolymer was extruded onto a copper conductor with a diameter of 1.00mm to obtain a coated wire. The wire coating extrusion molding conditions were as follows. a) Core conductor: Conductor diameter 1.00 mm b) Coating thickness: 0.50 mm c) Insulated wire diameter: 2.00 mm d) Wire pulling speed: 7m / min e) Extrusion conditions: • Single-screw extruder with cylinder shaft diameter = 20mm and L / D = 22 Die (inner diameter) / Tip (outer diameter) = 30.0 mm / 10.0 mm Extruder temperature settings: Barrel section C-1 (330°C), Barrel section C-2 (360°C), Barrel section C-3 (375°C), Head section H (390°C), Die section D-1 (405°C), Die section D-2 (395°C). Core wire preheating was set to 80°C.

[0160] (Variation in outer diameter) The outer diameter of the insulated wire was measured continuously for one hour using an outer diameter measuring instrument (Zumbach ODAC18XY). The outer diameter variation was determined by rounding the third decimal place of the outer diameter value that deviated the most from the predetermined outer diameter value (2.00 mm). The ratio of the absolute value of the difference between the predetermined outer diameter and the outer diameter variation value relative to the predetermined outer diameter (2.00 mm) (outer diameter variation rate) was calculated and evaluated according to the following criteria. (Percentage change in outer diameter (%)) = |(Value of change in outer diameter) - (Specified outer diameter)| / (Specified outer diameter) × 100 ±1%: The variation in outer diameter is 1% or less. ±2%: The variation in outer diameter is greater than 1% and less than or equal to 2%. ×: The variation rate of the outer diameter is more than 2%.

[0161] (Core wire corrosion test) The obtained insulated wires were cut to a length of 20 cm and left to stand for two weeks in a constant temperature and humidity chamber (FATC Junior SD-01) at 60°C and 95% humidity. After that, the coating was peeled off to expose the conductor, and the surface of the conductor was visually inspected and evaluated according to the following criteria. ○: No corrosion observed ×: Corrosion is observed.

[0162] (Toner release test) A φ14mm extruder (manufactured by Imoto Seisakusho Co., Ltd.) and a T-die were used to produce the film. The extrusion molding conditions were as follows: a) Winding speed: 1m / min b) Roll temperature: 120℃ c) Film width: 70mm d) Thickness: 0.10mm e) Extrusion conditions: • Single-screw extruder with cylinder shaft diameter = 14 mm and L / D = 20 Extruder temperature settings: Barrel section C-1 (330°C), Barrel section C-2 (350°C), Barrel section C-3 (370°C), T-die section (380°C)

[0163] A 50mm x 50mm test specimen was cut from the obtained 0.10mm thick film. The test specimen was placed in a stainless steel tray, and 3g of black toner powder was sprinkled on top in a circular pattern with a diameter of approximately 30mm. The tray lid was closed to create a sealed space, and the tray was placed in a constant temperature bath heated to 160°C. After 10 minutes, the tray was removed, allowed to cool to room temperature, and the test specimen was removed from the tray. The molten and solidified black toner was peeled off the test specimen, and the peeled surface of the test specimen was visually observed and evaluated according to the following criteria. ○: No black deposits were observed on the peeled surface of the test specimen. ×: Black deposits were observed on the peeled surface of the test specimen.

[0164] (Abrasion test) Using a pellet and heat press molding machine, sheet-like test specimens approximately 0.2 mm thick were prepared, and 10 cm x 10 cm test specimens were cut from them. The prepared test specimens were fixed to the test stand of a Taber abrasion tester (No. 101 Special Taber-type ablation tester, manufactured by Yasuda Seiki Seisakusho Co., Ltd.), and abrasion tests were performed using the Taber abrasion tester under the conditions of a load of 500 g, abrasion wheel CS-10 (polished 20 times with abrasive paper #240), and rotation speed of 60 rpm. The weight of the test specimen was measured after 1000 rotations, and the weight of the same test specimen was measured again after another 10000 rotations. The amount of abrasion was calculated using the following formula. Wear amount (mg)=M1-M2 M1: Weight of the test specimen after 1000 rotations (mg) M2: Weight of the test specimen after 10,000 rotations (mg)

[0165] (Nitrogen permeability coefficient) Sheet-like test specimens with a thickness of approximately 0.1 mm were prepared using a pellet and heat press molding machine. Using the obtained test specimens, nitrogen permeability was measured using a differential pressure gas permeability meter (L100-5000 type gas permeability meter, manufactured by Systech illinois) in accordance with the method described in JIS K7126-1:2006. Permeation area: 50.24 cm² 2 The nitrogen permeability values ​​were obtained at a test temperature of 70°C and a test humidity of 0%RH. Using the obtained nitrogen permeability values ​​and the thickness of the test specimen, the nitrogen permeability coefficient was calculated using the following formula. Nitrogen permeability coefficient (cm 3 ·mm / (m 2 24h (atm) = GTR × d GTR: Nitrogen permeability (cm) 3 / (m 2 24-hour ATM) d: Test specimen thickness (mm)

[0166] (Electrolyte permeability) Sheet-like test specimens with a thickness of approximately 0.2 mm were prepared using pellets and a heat press molding machine. (Test cup with a permeation area of ​​12.56 cm²) 2 10 g of dimethyl carbonate (DMC) was placed inside the container, covered with a sheet-like test piece, and sealed with a PTFE gasket. The sheet-like test piece and DMC were in contact, and the container was kept at 60°C for 30 days. After removal, the mass loss was measured after being left at room temperature for 1 hour. The DMC transmittance (g·cm / m³) was calculated using the following formula. 2 ) was sought. Electrolyte permeability (g cm / m 2 ) = Mass loss (g) × Thickness of sheet-like test specimen (cm) / Permeation area (m²) 2 )

[0167] (Transparency, rather) Sheet-like test specimens with a thickness of approximately 0.1 mm were prepared using pellets and a heat press molding machine. (Test cup with a permeation area of ​​12.56 cm²) 210 g of ethyl acetate was placed inside the container, covered with a sheet-like test piece, and sealed with a PTFE gasket. The sheet-like test piece was kept in contact with the ethyl acetate and maintained at 60°C for 45 days. After removal, it was left at room temperature for 1 hour and the mass loss was measured. The ethyl acetate transmittance (g·cm / m³) was calculated using the following formula. 2 ) was sought. Ethyl acetate (g·cm / m³) 2 ) = Mass loss (g) × Thickness of sheet-like test specimen (cm) / Permeation area (m²) 2 )

[0168] (Deflection under load at 110°C) Using pellets and a heat press molding machine, sheet-like test specimens approximately 4.2 mm thick were prepared. From these, 80 x 10 mm test specimens were cut out and heated in an electric furnace at 100°C for 20 hours. Except for using the obtained test specimens, tests were conducted using a heat distortion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) in accordance with the method described in JIS KK 7191-1, 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 load deflection ratio was calculated using the following formula. Sheets with a small load deflection ratio at 110°C exhibit superior rigidity at high temperatures of 110°C. Load deflection rate (%) = a² / a¹ × 100 a1: Thickness of the test specimen before testing (mm) a2: Deflection at 110℃ (mm)

[0169] (Tensile creep test) Tensile creep strain was measured using a Hitachi High-Tech Science TMA-7100. A sheet approximately 0.1 mm thick was prepared using a pellet and heat press molding machine, and a sample 2 mm wide and 22 mm long was created from the sheet. The sample was mounted on a measuring jig with a jig-to-jig distance of 10 mm. A cross-sectional load of 2.41 N / mm was applied to the sample. 2A load was applied to the sample, and it was left at 240°C. The displacement (mm) of the sample length was measured from 90 minutes to 300 minutes after the start of the test, and the ratio of the length displacement (mm) to the initial sample length (10 mm) (tensile creep strain (%)) was calculated. Sheets with a small tensile creep strain (%) measured under the conditions of 240°C and 300 minutes are less likely to elongate even when subjected to tensile load in a very high-temperature environment, and have excellent high-temperature tensile creep characteristics.

[0170] (Tensile strength maintenance rate after 60,000 cycles) The tensile strength retention rate after 60,000 cycles was measured using a Shimadzu Corporation MMT-250NV-10 fatigue testing machine. A sheet with a thickness of approximately 2.4 mm was prepared using a pellet and heat press molding machine, and a dumbbell-shaped sample (thickness 2.4 mm, width 5.0 mm, measurement section length 22 mm) was prepared using an ASTM D1708 microdumbbell. The sample was mounted on a measuring jig, and the measuring jig with the sample mounted was placed in a constant temperature bath at 150°C. Tensile tension was repeatedly applied in the uniaxial direction with a stroke of 0.2 mm and a frequency of 100 Hz, and the tensile strength (tensile strength when the stroke was +0.2 mm) was measured for each tension. The tensile strength retention rate after 60,000 cycles was calculated from the measured values ​​according to the following formula. Tensile strength retention rate after 60,000 cycles (%) = Tensile strength (60,000 cycles) (mN) / Tensile strength (5,000 cycles) (mN) × 100

[0171] The 60,000-cycle tensile strength retention rate is the ratio of the tensile strength after 60,000 cycles of repeated loading to the tensile strength after 5,000 cycles of repeated loading. Sheets with a high 60,000-cycle tensile strength retention rate maintain their initial tensile strength even after 60,000 cycles of repeated loading, demonstrating excellent resistance to degradation from repeated loading.

[0172] (Ozone exposure test) A copolymer was compressed and molded at 350°C under a pressure of 0.5 MPa to produce a 1 mm thick sheet, which was then cut into 10 × 20 mm sections to serve as samples for ozone exposure testing. Ozone gas (ozone / oxygen = 10 / 90 vol%) generated by an ozone generator (product name: SGX-A11MN (modified), manufactured by Sumitomo Seiki Kogyo Co., Ltd.) was connected to a PFA container filled with deionized water. Water vapor was added to the ozone gas by bubbling it through the deionized water, and the sample was then exposed to moist ozone gas by passing it through a PFA cell containing the sample at a rate of 0.7 liters / min at room temperature. After 150 days from the start of exposure, the sample was removed, its surface lightly rinsed with deionized water, and then the portion from the sample surface to a depth of 5-200 μm was observed using a transmission optical microscope at 100x magnification. The image was taken with a standard scale, and the 1 mm portion of the sample surface was photographed. 2 The number of cracks with a length of 10 μm or more per unit area was measured and evaluated according to the following criteria. ○: 10 or fewer cracks ×: More than 10 cracks

[0173] (Tube moldability) Using the pellets obtained in the example, tubes with an outer diameter of 10.0 mm and a wall thickness of 1.0 mm were extruded using a φ30 mm extrusion molding machine (manufactured by Tanabe Plastics Machinery). The extrusion molding conditions are as follows: a) Die inner diameter: 20mm b) Mandrel outer diameter: 13mm c) Sizing die inner diameter: 10.5 mm d) Pickup speed: 0.4 m / min e)Outer diameter: 10.0mm f) Wall thickness: 1.0mm g) Extrusion conditions: • Single-screw extruder with cylinder shaft diameter = 30mm and L / D = 22 Extruder temperature settings: 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 tubes were observed and evaluated according to the following criteria. The appearance of the tubes was confirmed visually. ○: The appearance is good. ×: The cross-section is not circular, and the appearance is poor, such as being flattened or having uneven thickness.

[0174] (Dielectric loss tangent) Cylindrical test specimens with a diameter of 2 mm were fabricated by melt molding pellets. The fabricated test specimens were placed in a 6 GHz cavity resonator manufactured by Kanto Electronics Applied Development Co., Ltd., and measured using a network analyzer manufactured by Agilent Technologies. The dielectric loss tangent (tanδ) at 20°C and 6 GHz was determined by analyzing the measurement results using "CPMA," analysis software manufactured by Kanto Electronics Applied Development Co., Ltd., on a PC connected to the network analyzer.

[0175] [Table 4]

Claims

1. It consists only of tetrafluoroethylene units and perfluoro(propyl vinyl ether) units. The perfluoro(propyl vinyl ether) unit content is 3.9 to 4.9% by mass relative to the total monomer units. The tetrafluoroethylene unit content is 95.1 to 96.1% by mass relative to the total monomer units. The melt flow rate at 372°C is 4.0 to 9.0 g / 10 min. -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH have a main chain carbon number of 10 ６ There are 40 or fewer per unit. Copolymer.

2. The copolymer according to claim 1, wherein the melt flow rate at 372°C is 5.0 to 9.0 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 described in claim 1 or 2.

5. A molded article containing the copolymer described in claim 1 or 2, wherein the molded article is a joint, film, bottle, gasket, lining material, pellet, wire coating, or tube.

6. A paint containing the copolymer according to claim 1 or 2.

7. An extruded article containing the copolymer according to claim 1 or 2.

8. A blow-molded article containing the copolymer according to claim 1 or 2.

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