CN116867821A

CN116867821A - Copolymer, molded body, injection molded body, and coated electric wire

Info

Publication number: CN116867821A
Application number: CN202280016143.4A
Authority: CN
Inventors: 井坂忠晴; 善家佑美; 山本有香里; 津田早登; 盐月敬三
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2021-02-26
Filing date: 2022-01-31
Publication date: 2023-10-10

Abstract

The present invention provides a copolymer comprising tetrafluoroethylene units and perfluoro (propyl vinyl ether) units, wherein the content of the perfluoro (propyl vinyl ether) units is 4.2 to 4.9% by mass relative to the total monomer units, the melt flow rate at 372 ℃ is 19.0 to 27.0g/10 min, and the number of functional groups is per 10 ⁶ The number of carbon atoms of the main chain is 50 or less.

Description

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

Technical Field

The present invention relates to a copolymer, a molded body, an injection molded body, and a coated electric wire.

Background

Patent document 1 describes a tetrafluoroethylene copolymer comprising tetrafluoroethylene and a compound represented by the following general formula (I)

Rf-O-CF＝CF ₂ (I)

Wherein Rf represents a perfluoroalkyl group having 1 to 5 carbon atoms, characterized in that the unstable terminal group is per 10 ⁶ Having 10 to 100 carbon atoms, the-COF and/or-COOH in the unstable terminal group being relative to 10 ⁶ The total number of carbon atoms is 10 to 100.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2005-320497

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a copolymer which can be molded at extremely high injection speeds by injection molding to give a thin and beautiful molded article, is less likely to corrode a mold or a coated core wire used in molding, can form a thin coating layer on a core wire having a small diameter at high speed by extrusion molding, and can give a molded article which is excellent in water vapor low permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air low permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures, and is less likely to crack even when in contact with a reagent, and is less likely to cause elution of fluorine ions into a reagent such as an electrolyte.

Means for solving the problems

According to the present invention, there is provided a copolymer comprising tetrafluoroethylene units and perfluoro (propyl vinyl ether) units, wherein the content of perfluoro (propyl vinyl ether) units is 4.2 to 4.9% by mass relative to the total monomer units, the melt flow rate at 372 ℃ is 19.0g/10 min to 27.0g/10 min, and the number of functional groups is per 10 ⁶ The number of carbon atoms of the main chain is 50 or less.

The copolymer of the present invention preferably has a melt flow rate of 20.0g/10 min to 25.0g/10 min at 372 ℃.

The copolymers of the invention preferably have a number of functional groups per 10 ⁶ The number of carbon atoms of the main chain is 20 or less.

Further, according to the present invention, there is provided an injection molded article comprising the copolymer.

Further, according to the present invention, there is provided a coated wire comprising a coating layer containing the copolymer.

Further, according to the present invention, there is provided a molded article comprising the copolymer, wherein the molded article is a valve, a gasket, a filter cover, a joint, or a wire coating.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a copolymer which can be molded at an extremely high injection rate by injection molding to give a thin and beautiful molded article, which is less likely to corrode a mold for molding or a coated core wire, which can be molded by extrusion molding to give a molded article which has a small diameter, which can form a thin coating layer on a core wire at a high rate by extrusion molding, which has excellent water vapor low permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air low permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperature, and which is less likely to crack even when in contact with a reagent, and which is less likely to cause elution of fluorine ions into a reagent such as an electrolyte.

Detailed Description

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

The copolymers of the present invention contain Tetrafluoroethylene (TFE) units and perfluoro (propyl vinyl ether) (PPVE) units.

A copolymer (PFA) containing TFE units and PPVE units is used as a material for forming a valve for controlling the pressure and flow rate of a fluid such as a reagent. Such valves are required to have abrasion resistance and excellent crack resistance in a reagent so that even if a load is applied to the valve due to stress caused by opening and closing of the valve, the valve is not damaged in a state of contact with the reagent. Such valves are sometimes used at high temperatures and require rigidity at high temperatures, high-temperature tensile creep characteristics, sealability at high temperatures, and mechanical strength. Further, such a valve has a complicated structure having a thin wall portion, and thus a good moldability is also required for the copolymer.

Patent document 1 describes: in the tetrafluoroethylene copolymer [ TFE copolymer ] composed of tetrafluoroethylene [ TFE ] and perfluoro (alkyl vinyl ether) [ PAVE ], PAVE unit is preferably more than 5% by mass in terms of improvement of crack resistance, and more preferably 8% by mass or less in terms of heat resistance. However, a copolymer which can provide a molded article which is less likely to crack even when in contact with a reagent, and which can provide a molded article excellent in moldability, mechanical properties at high temperature, rigidity at high temperature, high-temperature tensile creep properties, high-temperature abrasion resistance, low air permeability, low reagent permeability, transparency, sealability at high temperature, and low water vapor permeability has not been known.

The discovery is as follows: by properly adjusting the content of PPVE unit, melt Flow Rate (MFR) and the number of functional groups of the copolymer containing TFE unit and PPVE unit, the moldability of the copolymer is remarkably improved while the mold for molding is not easily corroded. And then found together: by using such a copolymer, cracks are less likely to occur even when in contact with a reagent, and a molded article excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, low air permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures can be obtained. By using the copolymer of the present invention, it is expected that the valve performance used at high temperatures can be dramatically improved.

Further, the copolymer of the present invention can form a thin coating layer on a core wire having a small diameter at a high speed by extrusion molding. Further, the obtained coating layer is less likely to corrode the core wire. Thus, the copolymer of the present invention can be used not only as a valve material but also for a wide range of applications such as wire coating.

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

The content of PPVE unit in the copolymer is 4.2 to 4.9 mass% relative to the total monomer units. The content of PPVE unit in the copolymer is more preferably 4.3 mass% or more, preferably 4.8 mass% or less, still more preferably 4.7 mass% or less, and still more preferably 4.6 mass% or less. If the PPVE unit content of the copolymer is too large, the air permeability, rigidity at a high temperature of 110℃and sealability at a high temperature and the water vapor permeability are poor. If the content of PPVE unit in the copolymer is too small, cracks tend to occur when the copolymer is brought into contact with a reagent, or the mechanical strength at 150 ℃ and the abrasion resistance at 90 ℃ and transparency are poor.

The TFE unit content of the copolymer is preferably 95.1 to 95.8 mass%, more preferably 95.2 mass% or more, most preferably 95.3 mass% or more, and even more preferably 95.7 mass% or less, based on the total monomer units. If the TFE unit content of the copolymer is too small, the air permeability, rigidity at a high temperature of 110℃and sealability at a high temperature and the water vapor permeability may be poor. If the TFE unit content of the copolymer is too large, cracks may easily occur when the copolymer is brought into contact with a reagent, or the mechanical strength at 150 ℃, abrasion resistance at 90 ℃ and transparency may be poor.

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

The copolymer may also contain monomer units derived from monomers copolymerizable with TFE and FAVE. In this case, the content of the monomer unit copolymerizable with TFE and PPVE is preferably 0 to 1.0 mass%, more preferably 0.05 to 0.7 mass%, and even more preferably 0.1 to 0.3 mass%, based on the total monomer units of the copolymer.

Examples of monomers copolymerizable with TFE and PPVE include Hexafluoropropylene (HFP) and CZ ¹ Z ² ＝CZ ³ (CF ₂ ) _n Z ⁴ (wherein Z is ¹ 、Z ² And Z ³ Identical or different, H or F, Z ⁴ H, F or Cl, n represents an integer of 2 to 10), and CF) ₂ ＝CF-ORf ¹ (wherein Rf ¹ Perfluoro (alkyl vinyl ether) [ PAVE ] represented by perfluoroalkyl group having 1 to 8 carbon atoms](except PPVE), and CF ₂ ＝CF-OCH ₂ -Rf ¹ (wherein Rf ¹ A perfluoroalkyl group having 1 to 5 carbon atoms. ) Alkyl perfluorovinyl ether derivatives shown and the like. Among them, HFP is preferable.

The copolymer is preferably at least one selected from the group consisting of a copolymer composed of only TFE units and PPVE units, and a TFE/HFP/PPVE copolymer, and more preferably a copolymer composed of only TFE units and PPVE units.

The Melt Flow Rate (MFR) of the copolymer is 19.0g/10 min to 27.0g/10 min. The MFR of the copolymer is preferably 20.0g/10 min or more, more preferably 21.0g/10 min or more, still more preferably 22.0g/10 min or more, most preferably 23.0g/10 min or more, preferably 26.9g/10 min or less, more preferably 26.0g/10 min or less, still more preferably 25.0g/10 min or less, particularly preferably 24.0g/10 min or less, most preferably 23.0g/10 min or less. By setting the MFR of the copolymer in the above range, the moldability of the copolymer is improved, and a molded article excellent in mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, high-temperature tensile creep properties, and transparency can be obtained, which hardly cause cracks even when in contact with a reagent.

In the present invention, MFR is a value obtained as a mass (g/10 min) of a polymer flowing out from a nozzle having an inner diameter of 2.1mm and a length of 8mm at 372℃under a 5kg load every 10 minutes using a melt index meter according to ASTM D1238.

The MFR can be adjusted by adjusting the kind and amount of a polymerization initiator used in polymerizing the monomers, the kind and amount of a chain transfer agent, and the like.

In the present invention, every 10 of the copolymer ⁶ The number of functional groups having the number of main chain carbon atoms is 50 or less. Every 10 of the copolymer ⁶ The number of functional groups having the number of main chain carbon atoms is preferably 40 or less, more preferably 30 or less, further preferably 20 or less, still more preferably 15 or less, particularly preferably 10 or less, and most preferably less than 6. By making the number of functional groups of the copolymer within the above range, the mold is not easily corroded even if the copolymer is molded by filling the copolymer into the mold, and the core wire is not easily corroded even when used as a coating of an electric wire. In addition, a thin coating layer can be formed on a core wire having a small diameter at a high speed by the extrusion molding method. Further, a molded article having excellent air permeability, low reagent permeability, and high-temperature tensile creep characteristics and being less likely to cause elution of fluorine ions into a reagent such as an electrolyte solution can be obtained. In particular, by properly adjusting the content of PPVE unit, melt Flow Rate (MFR) and the number of functional groups of the copolymer containing TFE unit and PPVE unit, a molded article exhibiting excellent low permeability to various reagents such as dimethyl carbonate and methyl ethyl ketone can be obtained.

The identification of the kind of the functional group and the measurement of the number of functional groups may be performed by infrared spectroscopic analysis.

Specifically, the number of functional groups was measured by the following method. First, the copolymer was cold-molded to prepare a film having a thickness of 0.25mm to 0.3 mm. The film was analyzed by fourier transform infrared spectroscopy to obtain the infrared absorption spectrum of the above copolymer, and to obtain a differential spectrum from the fully fluorinated background spectrum without functional groups. The specific absorption peak of the specific functional group in the copolymer was calculated for every 1X 10 based on the following formula (A) ⁶ Number of functional groups N of carbon atoms.

N＝I×K/t (A)

I: absorbance of light

K: correction coefficient

t: film thickness (mm)

For reference, the absorption frequency, molar absorptivity, and correction factor are shown in table 1 for some functional groups. The molar absorptivity was determined from FT-IR measurement data of the low molecular weight model compound.

TABLE 1

-CH ₂ CF ₂ H、-CH ₂ COF、-CH ₂ COOH、-CH ₂ COOCH ₃ 、-CH ₂ CONH ₂ The absorption frequency ratios of (C) are shown in the tables respectively for-CF ₂ H. -COF, free-COOH and bonded-COOH, -COOCH ₃ 、-CONH ₂ Is tens of kesse (cm) ^-1 )。

For example, the functional group number of-COF means the number of functional groups derived from-CF ₂ Absorption frequency of COF 1883cm ^-1 The number of functional groups obtained from the absorption peak at the site and the number of functional groups obtained from the absorption peak derived from-CH ₂ Absorption frequency of COF 1840cm ^-1 The total number of functional groups obtained from the absorption peak at the position.

The functional groups are functional groups present at the main chain end or side chain end of the copolymer and functional groups present in the main chain or side chain. The number of functional groups may be-cf=cf ₂ 、-CF ₂ H、-COF、-COOH、-COOCH ₃ 、-CONH ₂ and-CH ₂ Total number of OH.

The functional group is introduced into the copolymer, for example, by a chain transfer agent or a polymerization initiator used in producing the copolymer. For example, using alcohols as chain transfer agents, or using compounds having-CH ₂ In the case of peroxides of OH structure as polymerization initiators, -CH ₂ OH is introduced into the backbone end of the copolymer. In addition, the functional group is introduced into the terminal of the side chain of the copolymer by polymerizing a monomer having the functional group.

By subjecting the copolymer having such a functional group to a fluorination treatment, it is possible toA copolymer having the number of functional groups in the above range can be obtained. That is, the copolymer of the present invention is preferably a fluorinated copolymer. The copolymers of the invention also preferably have-CF ₃ End groups.

The melting point of the copolymer is preferably 295℃to 315℃and more preferably 300℃or higher, still more preferably 302℃or higher, particularly preferably 303℃or higher, most preferably 304℃or higher, and still more preferably 310℃or lower. When the melting point is within the above range, a copolymer which provides a molded article having more excellent mechanical properties particularly at high temperature and sealability at high temperature can be obtained.

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

The water vapor permeability of the copolymer is preferably 11.0 g.cm/m ² Hereinafter, it is more preferably 10.5 g.cm/m ² Hereinafter, it is more preferably 10.4 g.cm/m ² The following is given. The copolymer of the present invention has very excellent low water vapor permeability because the content of PPVE unit, melt Flow Rate (MFR) and the number of functional groups of the copolymer containing TFE unit and PPVE unit are properly adjusted. Therefore, when the molded article containing the copolymer of the present invention is used as a piping member (for example, a valve) for transporting a reagent in which it is not desired to mix moisture, it is possible to suppress permeation of water vapor in the outside air into the piping member.

In the present invention, the water vapor permeability can be measured at a temperature of 95℃for 30 days. Specific measurement of the water vapor permeability can be performed by the method described in examples.

The copolymer preferably has an air permeability coefficient of 380cm ³ ·mm/(m ² 24 h.atm) or less. The copolymer of the present invention has excellent low air permeability because the content of PPVE unit, melt Flow Rate (MFR) and the number of functional groups of the copolymer containing TFE unit and PPVE unit are appropriately adjusted.

In the present invention, the air permeability coefficient can be measured under the conditions of a test temperature of 70℃and a test humidity of 0% RH. Specific measurement of the air permeability coefficient can be performed by the method described in examples.

The electrolyte permeability of the copolymer is preferably 7.0 g.cm/m ² Hereinafter, it is more preferably 6.7 g.cm/m ² The following is given. The copolymer of the present invention has excellent electrolyte low permeability because the content of PPVE unit, melt Flow Rate (MFR) and the number of functional groups of the copolymer containing TFE unit and PPVE unit are appropriately adjusted. That is, by using the copolymer of the present invention, a molded article which is less likely to be permeable to a reagent such as an electrolyte can be obtained.

In the present invention, the electrolyte permeability can be measured at a temperature of 60℃for 30 days. Specific measurement of the electrolyte permeability can be performed by the method described in examples.

The copolymer preferably has a Methyl Ethyl Ketone (MEK) permeability of 65.0mg cm/m ² Day or less. The copolymer of the present invention has excellent MEK low permeability because the content of PPVE unit, melt Flow Rate (MFR) and the number of functional groups of the copolymer containing TFE unit and PPVE unit are appropriately adjusted. That is, by using the copolymer of the present invention, a molded article which is less likely to be permeable to a reagent such as MEK can be obtained.

In the present invention, MEK transmittance can be measured at a temperature of 60 ℃ for 60 days. Specific measurement of MEK transmission can be performed by the methods described in examples.

The amount of the eluted fluoride ion detected in the electrolyte impregnation test of the copolymer of the present invention is preferably 1.0ppm or less, more preferably 0.8ppm or less, and still more preferably 0.7ppm or less on a mass basis. By adjusting the amount of the eluted fluoride ions within the above range, the generation of gas such as HF in the nonaqueous electrolyte battery can be further suppressed, and deterioration in battery performance and short lifetime of the nonaqueous electrolyte battery can be further suppressed.

In the present invention, the electrolyte impregnation test can be performed as follows: a test piece having a weight equivalent to 10 molded articles (15 mm. Times.15 mm. Times.0.2 mm) was prepared using the copolymer, and a glass sample bottle containing the test piece and 2g of dimethyl carbonate (DMC) was placed in a constant temperature bath at 80℃for 144 hours.

The storage modulus (E') of the copolymer at 150℃is preferably 90MPa or more, more preferably 100MPa or more, preferably 1000MPa or less, more preferably 500MPa or less, and still more preferably 300MPa or less. When the storage modulus (E') of the copolymer at 150℃is in the above range, the sufficient rebound resilience can be continuously exhibited for a long period of time even at high temperatures, and a copolymer which provides a molded article having more excellent sealability at high temperatures can be obtained.

The storage modulus (E') can be measured by a dynamic viscoelasticity measurement at a temperature rising rate of 2 ℃/min and a frequency of 10Hz at a temperature ranging from 30 ℃ to 250 ℃. The storage modulus (E') at 150℃can be increased by adjusting the PPVE unit content and the Melt Flow Rate (MFR) of the copolymer.

The sealing pressure of the copolymer at 150℃is preferably 0.40MPa or more, more preferably 0.50MPa or more, still more preferably 0.60MPa or more, and the upper limit is not particularly limited and may be 3.00MPa or less. The seal pressure at 150℃can be increased by adjusting the PPVE unit content, melt Flow Rate (MFR) and the number of functional groups of the copolymer.

The sealing pressure can be calculated as follows: the height of the test piece (height of the test piece after compression deformation) was measured after the test piece obtained from the copolymer was deformed at a compression deformation rate of 50%, left at 150℃for 18 hours, and the compressed state was released, left at room temperature for 30 minutes, and the height of the test piece after compression deformation and the storage modulus (MPa) at 150℃were calculated from the following formula.

Sealing pressure (MPa) at 150 ℃ = (t) ₂ －t ₁ )/t ₁ ×E’

t ₁ : original height (mm) ×50% of test piece before compression deformation

t ₂ : height (mm) of test piece after compression deformation

E': storage modulus (MPa) at 150 DEG C

The haze value of the copolymer of the present invention is preferably 13.0% or less, more preferably 12.5% or less. When the haze value is in the above range, for example, in the case of obtaining a molded article such as a valve, a filter cover, a pipe, a joint, a bottle, a flowmeter or the like using the copolymer of the present invention, the inside of the molded article can be easily observed by visual observation, a camera or the like, and the flow rate of the content and the remaining amount can be easily confirmed. The haze value can be reduced by adjusting the PPVE unit content and Melt Flow Rate (MFR) of the copolymer. In the present invention, the haze value can be measured according to JIS K7136.

The copolymer of the present invention preferably has a tensile strength at 150℃of 15.5MPa or more, more preferably 16.0MPa or more. By setting the tensile strength at 150℃in the above range, even when the obtained molded article is used at a high temperature, deformation can be suppressed, and a longer life of the molded article can be achieved. In addition, even when pressure is applied from the high-temperature fluid, deformation and damage of the molded body can be prevented, and therefore, a large flow rate of the high-temperature fluid can be circulated. In the present invention, the tensile strength at 150℃can be measured according to ASTM D638. The tensile strength can be increased by adjusting the PPVE unit content, melt Flow Rate (MFR) and the number of functional groups of the copolymer.

The copolymer of the present invention can be produced by a polymerization method such as suspension polymerization, solution polymerization, emulsion polymerization, or bulk polymerization. As the polymerization method, emulsion polymerization or suspension polymerization is preferable. In these polymerizations, the conditions such as temperature and pressure, polymerization initiator, and other additives may be appropriately set according to the composition and amount of the copolymer.

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

The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, and the following are exemplified as typical examples:

dialkyl peroxycarbonates such as di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, and di-2-ethoxyethyl peroxydicarbonate;

peroxyesters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate;

dialkyl peroxides such as di-t-butyl peroxide;

di [ fluoro (or fluoro chloro) acyl ] peroxides; etc.

As bis [ fluoro (or fluoro chloro) acyl groups]The peroxides include [ (RfCOO) & lt- & gt ]] ₂ (Rf is perfluoroalkyl, omega-hydroperfluoroalkyl or fluorochloroalkyl).

Examples of the di [ fluoro (or fluorochloroacyl ] peroxides include di (ω -hydro-dodecafluoroheptanoyl) peroxide, di (ω -hydro-hexadecanoyl) peroxide, di (perfluoropropionyl) peroxide, di (perfluorobutanoyl) peroxide, di (perfluoropentanoyl) peroxide, di (perfluorohexanoyl) peroxide, di (perfluoroheptanoyl) peroxide, di (perfluorooctanoyl) peroxide, di (perfluorononanoyl) peroxide, di (ω -chloro-hexafluorobutanoyl) peroxide, di (ω -chloro-dodecafluoroheptanoyl) peroxide, di (ω -chloro-dodecafluorooctanoyl) peroxide, ω -hydro-dodecafluoroheptanoyl-peroxide, ω -chloro-hexafluorobutanoyl-peroxide, ω -hydrododecafluoroheptanoyl-perfluorobutanoyl-peroxide, di (perfluoroheptanoyl) peroxide, di (dichloro-heptanoyl) peroxide, di (dichloro-dodecanoyl) peroxide, and di (dichloro-dodecanoyl) dodecanoyl peroxide.

The water-soluble radical polymerization initiator may be a known water-soluble peroxide, and examples thereof include ammonium salts such as persulfuric acid, perboric acid, perchloric acid, perphosphoric acid, and percarbonic acid, potassium salts, sodium salts, disuccinic acid peroxide, and organic peroxides such as dipentaerythritol peroxide, t-butyl peroxymaleate, and t-butyl hydroperoxide. The reducing agent such as sulfite may be used in combination with the peroxide in an amount of 0.1 to 20 times the amount of the peroxide.

In the polymerization, a surfactant, a chain transfer agent and a solvent may be used, and conventionally known ones may be used, respectively.

As the surfactant, a known surfactant can be used, and for example, a nonionic surfactant, an anionic surfactant, a cationic surfactant, and the like can be used. Among them, the fluorinated anionic surfactant is preferable, and the fluorinated anionic surfactant having 4 to 20 carbon atoms, which may be linear or branched, and which may or may not contain ether-bonded oxygen (i.e., may have an oxygen atom interposed between carbon atoms), is more preferable. The amount of the surfactant to be added (relative to the polymerization water) is preferably 50ppm to 5000ppm.

Examples of the chain transfer agent include: hydrocarbons such as ethane, isopentane, n-hexane, and cyclohexane; aromatic compounds such as toluene and xylene; ketones such as acetone; acetate esters such as ethyl acetate and butyl acetate; alcohols such as methanol and ethanol; mercaptans such as methyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride and methyl chloride; etc. The amount of the chain transfer agent to be added may vary depending on the amount of the chain transfer constant of the compound to be used, and is usually in the range of 0.01 to 20% by mass relative to the polymerization solvent.

Examples of the solvent include water, a mixed solvent of water and alcohol, and the like.

In the suspension polymerization, a fluorine-based solvent may be used in addition to water. As the fluorine-based solvent, CH may be mentioned ₃ CClF ₂ 、CH ₃ CCl ₂ F、CF ₃ CF ₂ CCl ₂ H、CF ₂ ClCF ₂ Hydrochlorofluoroalkanes such as CFHCl; CF (compact flash) ₂ ClCFClCF ₂ CF ₃ 、CF ₃ CFClCFClCF ₃ Isophlorofluoroalkanes; CF (compact flash) ₃ CFHCFHCF ₂ CF ₂ CF ₃ 、CF ₂ HCF ₂ CF ₂ CF ₂ CF ₂ H、CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ Hydrofluoroalkanes such as H; CH (CH) ₃ OC ₂ F ₅ 、CH ₃ OC ₃ F ₅ CF ₃ CF ₂ CH ₂ OCHF ₂ 、CF ₃ CHFCF ₂ OCH ₃ 、CHF ₂ CF ₂ OCH ₂ F、(CF ₃ ) ₂ CHCF ₂ OCH ₃ 、CF ₃ CF ₂ CH ₂ OCH ₂ CHF ₂ 、CF ₃ CHFCF ₂ OCH ₂ CF ₃ Isohydrofluoroethers; perfluorocyclobutane, CF ₃ CF ₂ CF ₂ CF ₃ 、CF ₃ CF ₂ CF ₂ CF ₂ CF ₃ 、CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF ₃ Among them, perfluoroalkanes are preferable. The amount of the fluorine-based solvent to be used is preferably 10 to 100% by mass based on the aqueous medium in view of suspension property and economy.

The polymerization temperature is not particularly limited, and may be 0 to 100 ℃. The polymerization pressure is appropriately determined depending on the kind and amount of the solvent used, the vapor pressure, the polymerization temperature, and other polymerization conditions, and may be generally 0 to 9.8MPaG.

When an aqueous dispersion containing a copolymer is obtained by polymerization, the copolymer contained in the aqueous dispersion can be precipitated, washed, and dried to recover the copolymer. In addition, in the case where the copolymer is obtained as a slurry by polymerization, the copolymer can be recovered by taking out the slurry from the reaction vessel, washing it, and drying it. The copolymer can be recovered in the form of a powder by drying.

The copolymer obtained by polymerization may be molded into pellets. The molding method for molding the pellets is not particularly limited, and conventionally known methods can be used. For example, a method of melt-extruding a copolymer using a single screw extruder, a twin screw extruder, or a tandem extruder, cutting the copolymer into a predetermined length, and molding the copolymer into pellets, and the like can be mentioned. The extrusion temperature at the time of melt extrusion is required to be changed depending on the melt viscosity of the copolymer and the production method, and is preferably from +20℃to +140℃of the melting point of the copolymer. The method of cutting the copolymer is not particularly limited, and conventionally known methods such as a wire cutting method, a thermal cutting method, an underwater cutting method, and a sheet cutting method can be employed. The volatile components in the pellets may also be removed by heating the resulting pellets (degassing treatment). The obtained pellets may be treated by contacting them with warm water at 30 to 200 ℃, steam at 100 to 200 ℃ or hot air at 40 to 200 ℃.

Can alsoTo fluorinate the copolymer obtained by polymerization. The fluorination treatment may be performed by contacting the copolymer that has not been subjected to the fluorination treatment with a fluorine-containing compound. By fluorination treatment, the-COOH, -COOCH-of the copolymer can be obtained ₃ 、-CH ₂ OH、-COF、-CF＝CF ₂ 、-CONH ₂ Isothermally labile functional groups and relatively thermally stable-CF ₂ Conversion of functional groups such as H to extremely thermally stable-CF ₃ . As a result, the-COOH, -COOCH-of the copolymer can be used ₃ 、-CH ₂ OH、-COF、-CF＝CF ₂ 、-CONH ₂ and-CF ₂ The total number of H (the number of functional groups) is easily adjusted to be within the above-mentioned range.

The fluorine-containing compound is not particularly limited, and examples thereof include a fluorine radical source that generates a fluorine radical under the fluorination treatment conditions. As the fluorine radical source, F may be mentioned ₂ Gas, coF ₃ 、AgF ₂ 、UF ₆ 、OF ₂ 、N ₂ F ₂ 、CF ₃ OF, fluorinated halogens (e.g. IF ₅ 、ClF ₃ ) Etc.

F ₂ The fluorine radical source such as gas may be used at a concentration of 100%, but from the viewpoint of safety, it is preferably used by mixing with an inactive gas and diluting to 5 to 50% by mass, more preferably 15 to 30% by mass. The inert gas may be nitrogen, helium, argon, or the like, and nitrogen is preferable from the viewpoint of economy.

The conditions of the fluorination treatment are not particularly limited, and the copolymer in a molten state may be brought into contact with the fluorine-containing compound, but may be usually conducted at a temperature of 20 to 240℃and more preferably 100 to 220℃below the melting point of the copolymer. The fluorination treatment is generally carried out for 1 to 30 hours, preferably 5 to 25 hours. The fluorination treatment preferably involves reacting the copolymer which has not been subjected to the fluorination treatment with fluorine gas (F ₂ Gas) contact.

The copolymer of the present invention may be mixed with other components as needed to obtain a composition. Examples of the 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, perfumes, oils, softeners, dehydrofluorination agents, and the like.

Examples of the filler include silica, kaolin, clay, organized clay, talc, mica, alumina, calcium carbonate, calcium terephthalate, titanium oxide, calcium phosphate, calcium fluoride, lithium fluoride, crosslinked polystyrene, potassium titanate, carbon, boron nitride, carbon nanotubes, and glass fibers. Examples of the conductive agent include carbon black. Examples of the plasticizer include dioctyl phthalate and pentaerythritol. Examples of the processing aid include carnauba wax, sulfone compound, low molecular weight polyethylene, and fluorine-based aid. Examples of the dehydrofluorination agent include organic onium and amidines.

As the other components, other polymers than the above copolymers may be used. Examples of the other polymer include a fluororesin other than the above copolymer, a fluororubber, a nonfluorinated polymer, and the like.

The method for producing the composition includes: a method of dry-mixing the copolymer with other components; a method in which the copolymer and other components are mixed in advance by a mixer, and then melt-kneaded by a kneader, a melt extruder, or the like; etc.

The copolymer or the composition of the present invention can be used as a processing aid, a molding material, or the like, and is preferably used as a molding material. Aqueous dispersions, solutions, suspensions, and copolymer/solvent systems of the copolymers of the present invention may also be utilized, which may be applied as coatings or used for encapsulation, impregnation, film casting. However, the copolymer of the present invention is preferably used as the molding material because it has the above-mentioned characteristics.

The copolymer of the present invention or the above composition may be molded to obtain a molded article.

The method for molding the copolymer or the composition is not particularly limited, and examples thereof include injection molding, extrusion molding, compression molding, blow molding, transfer molding, rotational molding, and roll lining molding. Among the molding methods, extrusion molding, compression molding, injection molding or transfer molding is preferable, and injection molding is more preferable because a molded article can be produced with high productivity. That is, the molded article is preferably an extrusion molded article, a compression molded article, an injection molded article or a transfer molded article, and more preferably an injection molded article, an extrusion molded article or a transfer molded article, and even more preferably an injection molded article, since it can be produced at high productivity. By molding the copolymer of the present invention by injection molding, a thin and beautiful molded article can be obtained by molding at an extremely high injection speed.

Examples of molded articles containing the copolymer of the present invention include nuts, bolts, joints, films, bottles, gaskets, wire coatings, pipes, hoses, pipes, valves, sheets, seals, gaskets, tanks, rolls, containers, taps, connectors, filter housings, filter covers, flow meters, pumps, wafer carriers, wafer cassettes, and the like.

The copolymer, the composition or the molded article of the present invention can be used for the following purposes, for example.

A film for packaging food, a lining material for a fluid transfer line used in a food manufacturing process, a gasket, a sealing material, a fluid transfer member for a food manufacturing apparatus such as a sheet;

reagent delivery members such as plugs for chemicals, packaging films, liners for fluid delivery lines used in chemical manufacturing processes, gaskets, seals, sheets, etc.;

inner lining members of reagent tanks and piping of chemical equipment and semiconductor factories;

fuel delivery members such as hoses and sealing materials used in AT devices of automobiles such as O (square) rings/tubes/gaskets, valve core materials, hoses and sealing materials used in fuel systems and peripheral devices of automobiles;

flange gaskets, shaft seals, stem seals, sealing materials, brake hoses for automobiles such as hoses, air conditioning hoses, radiator hoses, wire coating materials, and other automobile components used in engines and peripheral devices of automobiles;

A reagent transporting member for a semiconductor device, such as an O-ring, a tube, a gasket, a valve body material, a hose, a sealing material, a roller, a gasket, a diaphragm, and a joint of a semiconductor manufacturing apparatus;

coating and ink members such as coating rolls, hoses, tubes, ink containers for coating equipment;

pipes such as pipes for food and drink, hoses, belts, gaskets, joints, and other food and drink conveying members, food packaging materials, and glass cooking devices;

a waste liquid transporting member such as a tube or a hose for transporting waste liquid;

high-temperature liquid transmission members such as pipes and hoses for high-temperature liquid transmission;

a member for steam piping such as a pipe or a hose for steam piping;

a corrosion-resistant belt for piping such as a belt wound around piping such as a deck of a ship;

various coating materials such as a wire coating material, an optical fiber coating material, a transparent surface coating material provided on a light incidence side surface of a photovoltaic element of a solar cell, and a back surface agent;

sliding components such as diaphragms and various gaskets of the diaphragm pump;

weather resistant covers for agricultural films, various roofing materials, sidewalls, and the like;

glass-like coating materials such as interior materials and incombustible fire-resistant safety glass used in the construction field;

Lining materials such as laminated steel sheets used in the field of home appliances and the like.

Further examples of the fuel delivery member used in the fuel system of the automobile include a fuel hose, a filler hose, and an evaporator hose. The fuel delivery member can be used as a fuel delivery member for acid-resistant gasoline, alcohol-resistant fuel, and fuel to which a gasoline additive such as methyl t-butyl ether or amine-resistant additive is added.

The above-mentioned chemical stopper and packaging film have excellent chemical resistance to acids and the like. The reagent transporting member may be an anti-corrosive tape wound around a piping of a chemical apparatus.

Examples of the molded article include radiator chambers, reagent tanks, bellows, separators, rolls, gasoline tanks, waste liquid transport containers, high-temperature liquid transport containers, fishery and fish farming tanks, and the like of automobiles.

Further, examples of the molded article include a bumper, a door trim, an instrument panel, a food processing device, a cooking machine, water/oil resistant glass, a lighting-related instrument, an indication board and a housing for OA instruments, an electric lighting sign, a display screen, a liquid crystal display, a cellular phone, a printer chassis, electric and electronic parts, sundries, a dustbin, a bathtub, an entire bathroom, a ventilator, a lighting frame, and the like.

The molded article containing the copolymer of the present invention is excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures, and is less likely to crack even when in contact with a reagent, and is less likely to cause elution of fluorine ions into a reagent such as an electrolyte, and therefore can be suitably used for nuts, bolts, joints, gaskets, valves, taps, connectors, filter housings, filter covers, flowmeters, pumps, and the like. For example, the present invention can be suitably used as a piping member (particularly, a joint) for transporting a reagent or a flowmeter case having a flow path for a reagent in a flowmeter. The piping member and the flowmeter case of the present invention have a small haze value, are excellent in low vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, low air permeability, low reagent permeability, high-temperature tensile creep properties, and sealability at high temperatures, and are less likely to generate cracks even when in contact with a reagent. Therefore, the piping member and the flowmeter case of the present invention are excellent in visibility, and particularly in the flowmeter case, the float inside can be easily observed by visual observation, a camera, or the like, and the piping member and the flowmeter case can be suitably used for flow rate measurement of a reagent at about 150 ℃. Further, the piping member and the flowmeter case according to the present invention can be manufactured at an extremely high injection rate even in the case of having a thin wall portion without corroding a mold for molding, and are excellent in appearance.

The molded article containing the copolymer of the present invention is excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low reagent permeability, high-temperature tensile creep property, transparency, and sealability at high temperature, and is less likely to generate cracks even when in contact with a reagent, and less likely to cause elution of fluorine ions into a reagent such as an electrolyte, even in the case of having a thin wall portion, and therefore can be suitably used as a compressed member such as a gasket or a gasket.

The compressed member of the present invention exhibits a high sealing pressure even when deformed at a high compression deformation rate. The compressed member of the present invention can be used in a state of being compressed and deformed at a compression deformation rate of 10% or more, and can be used in a state of being compressed and deformed at a compression deformation rate of 20% or more or 25% or more. By deforming the compressed member of the present invention at such a high compression set, a certain rebound resilience can be maintained for a long period of time, and sealing properties and insulating properties can be maintained for a long period of time.

The compressed member of the present invention exhibits a high storage modulus, a high recovery amount, and a high sealing pressure even when deformed at a high compression deformation rate at a high temperature. The compressed member of the present invention can be used in a state of being compressed and deformed at a compression deformation rate of 10% or more at 150 ℃ or more, and can be used in a state of being compressed and deformed at a compression deformation rate of 20% or more or 25% or more at 150 ℃. By deforming the compressed member of the present invention at such a high temperature with a high compression deformation rate, a certain rebound resilience can be maintained for a long period of time even at a high temperature, and sealing properties and insulating properties at a high temperature can be maintained for a long period of time.

The compression set is the compression set at the portion where the compression set is the largest when the compressed member is compressed. For example, when a flat compressed member is used in a state compressed in the thickness direction, the compression set is the compression set in the thickness direction. For example, when the member is used in a state where only a part of the member is compressed, the member is a part having the highest compression set among compression sets of the compressed part.

The size and shape of the compressed member of the present invention may be appropriately set according to the application, and are not particularly limited. The compressed member of the present invention may be annular in shape, for example. The compressed member of the present invention may have a circular shape, an elliptical shape, a quadrangular shape with rounded corners, or the like in a plan view, and may have a through hole in a central portion thereof.

The compressed member of the present invention is preferably used as a member for constituting a nonaqueous electrolyte battery. The compressed member of the present invention is excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures, and is less likely to cause elution of fluorine ions into an electrolyte, and therefore is particularly suitable as a member used in a state of contact with a nonaqueous electrolyte in a nonaqueous electrolyte battery. That is, the compressed member of the present invention may have a liquid receiving surface of the nonaqueous electrolyte in the nonaqueous electrolyte battery.

The compressed member of the present invention is less likely to cause elution of fluorine ions into a nonaqueous electrolytic solution. Therefore, by using the compressed member of the present invention, an increase in the fluoride ion concentration in the nonaqueous electrolytic solution can be suppressed. As a result, by using the compressed member of the present invention, the generation of gas such as HF in the nonaqueous electrolyte battery can be suppressed, or the deterioration of the battery performance and the reduction of the lifetime of the nonaqueous electrolyte battery can be suppressed.

The compressed member of the present invention can further suppress the generation of gas such as HF in the nonaqueous electrolyte battery or can further suppress the deterioration of battery performance and the reduction of lifetime of the nonaqueous electrolyte battery, and therefore the amount of dissolved fluorine ions detected in the electrolyte impregnation test is preferably 1.0ppm or less, preferably 0.8ppm or less, more preferably 0.7ppm or less on a mass basis. The electrolyte impregnation test can be performed as follows: a test piece having a weight equivalent to 10 molded articles (15 mm. Times.15 mm. Times.0.2 mm) was produced using the compressed member, and a glass sample bottle containing the test piece and 2g of dimethyl carbonate (DMC) was placed in a constant temperature bath at 80℃for 144 hours.

The compressed member of the present invention is not easily permeable to water vapor. Therefore, by using the compressed member of the present invention, the permeation of water vapor from the outside through the secondary battery can be suppressed. As a result, by using the compressed member of the present invention, deterioration in battery performance and short lifetime of the nonaqueous electrolyte battery can be suppressed.

The compressed member of the present invention preferably has a water vapor permeability of 11.0 g/cm/m because deterioration in battery performance and short lifetime of the nonaqueous electrolyte battery can be further suppressed ² The ratio is more preferably 10.5 g.cm/m ² The ratio is more preferably 10.4 g.cm/m ² The following is given. The water vapor permeability of the compressed member can be measured at a temperature of 95℃for 30 days.

The nonaqueous electrolyte battery is not particularly limited as long as it is a battery provided with a nonaqueous electrolyte, and examples thereof include a lithium ion secondary battery and a lithium ion capacitor. Further, as a member constituting the nonaqueous electrolyte battery, a sealing member, an insulating member, and the like can be given.

The nonaqueous electrolyte is not particularly limited, and 1 or 2 or more of known solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ -butyrolactone, 1, 2-dimethoxyethane, 1, 2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and methylethyl carbonate may be used. The nonaqueous electrolyte battery may further include an electrolyte. The electrolyte is not particularly limited, and LiClO may be used ₄ 、LiAsF ₆ 、LiPF ₆ 、LiBF ₄ 、LiCl、LiBr、CH ₃ SO ₃ Li、CF ₃ SO ₃ Li, cesium carbonate, and the like.

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

The compressed member of the present invention is excellent in heat resistance and excellent in sealability at high temperatures, and therefore can be suitably used in a high-temperature environment. For example, the compressed member of the present invention can be used in an environment where the maximum temperature is 40 ℃ or higher. For example, the compressed member of the present invention can be used in an environment where the maximum temperature is 150 ℃ or higher. As a case where the compressed member of the present invention can be brought to such a high temperature, for example, a case where after the compressed member is mounted to a battery in a compressed state, another battery member is mounted to the battery by welding; a case where the nonaqueous electrolyte battery generates heat; etc.

The compressed member of the present invention is excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures, and is less likely to cause elution of fluorine ions into an electrolyte, and therefore can be suitably used as a sealing member for a nonaqueous electrolyte battery or an insulating member for a nonaqueous electrolyte battery. For example, in the case of charging a battery such as a nonaqueous electrolyte secondary battery, the temperature of the battery may be temporarily 40 ℃ or higher, in particular, temporarily 150 ℃ or higher. The compressed member of the present invention is used in a battery such as a nonaqueous electrolyte secondary battery by deforming at a high compression deformation rate even at a high temperature, and does not deteriorate high rebound resilience even when it is in contact with a nonaqueous electrolyte at a high temperature. Therefore, in the case where the compressed member of the present invention is used as a sealing member, it has excellent sealing properties and can maintain the sealing properties for a long period of time even at high temperatures. In addition, the compressed member of the present invention has excellent insulating properties because it contains the copolymer. Therefore, when the compressed member of the present invention is used as an insulating member, the compressed member is firmly adhered to 2 or more conductive members, and short-circuiting can be prevented for a long period of time.

The copolymer of the present invention is suitable as a material for forming an electric wire coating because it can form a coating layer on a core wire having a small diameter at a high drawing speed in a thin manner and can form a coating layer having excellent electric characteristics by molding the copolymer of the present invention by an extrusion molding method, without causing a coating break even when the diameter of the core wire is small. Therefore, the coated wire having the coating layer containing the copolymer of the present invention has almost no defects such as spark generation even when the diameter of the core wire is small and the coating layer is thin, and is excellent in electrical characteristics.

The coated wire comprises a core wire and a coating layer provided around the core wire and containing the copolymer of the present invention. For example, an extrusion molded article obtained by melt-extruding the copolymer of the present invention on a core wire may be used as the coating layer. The covered wire is suitable for a LAN Cable (ethernet Cable), a high-frequency transmission Cable, a flat Cable, a heat-resistant Cable, and the like, and is suitable for a transmission Cable such as a LAN Cable (ethernet Cable), a high-frequency transmission Cable, and the like.

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

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

The thickness of the coating layer is preferably 0.1mm to 3.0mm. The thickness of the coating layer is also preferably 2.0mm or less. By using the copolymer, a coating layer having a thickness of 0.5mm or less, 0.4mm or less, 0.3mm or less, or 0.2mm or less can be formed without any problem.

As the high-frequency transmission cable, a coaxial cable may be mentioned. The coaxial cable generally has a structure in which an inner conductor, an insulating coating layer, an outer conductor layer, and a protective coating layer are laminated in this order from a core portion to an outer peripheral portion. The molded article containing the copolymer of the present invention can be suitably used as an insulating coating layer containing the copolymer. The thickness of each layer in the above-described structure is not particularly limited, and in general, the diameter of the inner conductor is about 0.1mm to 3mm, the thickness of the insulating coating layer is about 0.3mm to 3mm, the thickness of the outer conductor layer is about 0.5mm to 10mm, and the thickness of the protective coating layer is about 0.5mm to 2mm.

The coating may contain bubbles, which are preferably uniformly distributed in the coating.

The average cell diameter of the bubbles is not limited, and is, for example, preferably 60 μm or less, more preferably 45 μm or less, further preferably 35 μm or less, further preferably 30 μm or less, particularly preferably 25 μm or less, and particularly preferably 23 μm or less. The average cell diameter is preferably 0.1 μm or more, more preferably 1 μm or more. The average bubble diameter can be obtained by obtaining an electron microscope image of a wire cross section, calculating the diameter of each bubble by image processing, and averaging.

The foaming ratio of the coating layer may be 20% or more. More preferably 30% or more, still more preferably 33% or more, still more preferably 35% or more. The upper limit is not particularly limited, and is, for example, 80%. The upper limit of the foaming ratio may be 60%. The foaming ratio was obtained as ((specific gravity of wire coating material-specific gravity of coating layer)/specific gravity of wire coating material) ×100. The foaming ratio can be appropriately adjusted according to the application by, for example, adjusting the amount of gas inserted into an extruder to be described later, or by selecting the type of dissolved gas.

The coated wire may further include a different layer (outer layer) around the coating layer, and a different layer may be provided between the core wire and the coating layer. When the coating layer contains bubbles, the electric wire of the present invention may have a 2-layer structure (skin-foam) in which a non-foam layer is interposed between the core wire and the coating layer; a 2-layer structure (foam-skin) having a non-foam layer coated on the outer layer; further, the outer layer of the skin-foam was covered with a 3-layer structure (skin-foam-skin) of a non-foam layer. The non-expanded layer is not particularly limited, and may be a resin layer composed of a polyolefin resin such as TFE/HFP copolymer, TFE/PAVE copolymer, TFE/ethylene copolymer, vinylidene fluoride polymer, polyethylene [ PE ], or a resin such as polyvinyl chloride [ PVC ].

The coated wire can be produced, for example, by heating the copolymer using an extruder, extruding the copolymer onto the core wire in a molten state, and forming a coating layer.

In forming the coating layer, the gas may be introduced into the copolymer in a molten state by heating the copolymer, thereby forming the coating layer containing bubbles. As the gas, for example, a gas such as difluoromethane, nitrogen, carbon dioxide, or the like, or a mixture of the above gases can be used. The gas may be introduced into the heated copolymer as a pressurized gas or may be produced by mixing a chemical blowing agent into the copolymer. The gas is dissolved in the copolymer in a molten state.

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

The product for transmitting a high-frequency signal is not particularly limited as long as it is a product for transmitting a high-frequency signal, and examples thereof include (1) a molded plate such as an insulating plate for a high-frequency circuit, an insulating material for a connecting member, and a printed wiring board, (2) a molded body such as a base or a radome for a high-frequency vacuum tube, and (3) a covered wire such as a coaxial cable or a LAN cable. The high-frequency signal transmission product can be suitably used for satellite communication equipment, mobile telephone base stations, and other equipment utilizing microwaves, particularly microwaves of 3GHz to 30 GHz.

In the above-mentioned high-frequency signal transmission product, the copolymer of the present invention is suitable for use as an insulator in view of low dielectric loss tangent.

The molded plate (1) is preferably a printed wiring board in terms of obtaining good electrical characteristics. The printed wiring board is not particularly limited, and examples thereof include printed wiring boards for electronic circuits of mobile phones, various computers, communication devices, and the like. As the molded article (2), a radome is preferable in terms of low dielectric loss.

The copolymer of the present invention is molded by injection molding at a high injection speed, and a thin and beautiful sheet can be obtained with high productivity. The molded article containing the copolymer of the present invention is excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures, and is less likely to crack even when in contact with a reagent, and is less likely to cause elution of fluorine ions into water. Therefore, the molded article containing the copolymer of the present invention can be suitably used as a film or sheet.

The film of the present invention is useful as a release film. The release film can be produced by molding the copolymer of the present invention by melt extrusion molding, calender molding, press molding, casting molding, or the like. From the viewpoint of obtaining a uniform film, a release film can be produced by melt extrusion molding.

The film of the present invention can be applied to the surface of a roll used in an OA apparatus. The copolymer of the present invention can be molded into a desired shape by extrusion molding, compression molding, press molding, etc., and formed into a sheet, film, tube shape, etc., for use as a surface material for OA equipment rolls, OA equipment belts, etc. In particular, thin-walled tubes and films can be produced by melt extrusion.

The molded article containing the copolymer of the present invention is excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low reagent permeability, high-temperature tensile creep properties and transparency, and is less likely to crack even when in contact with a reagent, and therefore can be suitably used as a bottle or a tube. The bottle or tube of the present invention can easily visually confirm the content, and is not easily damaged in use.

The copolymer of the present invention can be molded by injection molding at an extremely high injection speed even in the case of having a thin wall portion, and is less likely to corrode a mold for molding. Further, the obtained molded article is excellent in appearance, low in water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low in reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperature, and is less likely to generate cracks even when in contact with a reagent. Thus, the copolymers of the present invention may be suitable for use in valves. The valve comprising the copolymer of the present invention can be produced at low cost with extremely high productivity without corroding a mold, and is not easily damaged even if repeatedly opened and closed at a high frequency, and is excellent in low water vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, low reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures. The valve of the present invention is excellent in low vapor permeability, mechanical properties at 150 ℃, rigidity at 110 ℃, abrasion resistance at 90 ℃, air permeability, reagent permeability, high-temperature tensile creep properties, transparency, and sealability at high temperatures, and therefore can be suitably used for controlling fluids at 100 ℃ or higher, particularly around 150 ℃. In the valve of the present invention, at least the liquid receiving portion may be composed of the above-mentioned copolymer. The valve of the present invention may be a valve having a housing containing the copolymer.

While the embodiments have been described above, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the claims.

Examples

Next, embodiments of the present invention will be described with reference to examples, but the present invention is not limited to the examples.

The values of the examples were measured by the following methods.

(content of monomer units)

The content of each monomer unit was measured by an NMR analyzer (for example, AVANCE300 high temperature probe manufactured by Bruker Biospin Co.).

(melt flow Rate (MFR))

The mass (G/10 minutes) of the polymer flowing out from a nozzle having an inner diameter of 2.1mm and a length of 8mm per 10 minutes was determined by using a melt index analyzer G-01 (manufactured by Toyo Seisakusho-Sho Co., ltd.) at 372℃under a 5kg load in accordance with ASTM D1238.

(number of functional groups)

The pellets of the copolymer were cold-molded to prepare a film having a thickness of 0.25mm to 0.3 mm. By Fourier transform infrared Spectrum analysis device [ FT-IR (Spectrum One manufactured by Perkinelmer Co.)]The film was scanned 40 times and analyzed to obtain an infrared absorption spectrum and a differential spectrum from a fully fluorinated background spectrum without functional groups. The absorbance peak of the specific functional group shown by the differential spectrum was calculated for every 1X 10 in the sample according to the following formula (A) ⁶ Number of functional groups N of carbon atoms.

N＝I×K/t (A)

I: absorbance of light

K: correction coefficient

t: film thickness (mm)

For reference, regarding the functional groups in the present invention, the absorption frequency, molar absorptivity, and correction coefficient are shown in table 2. The molar absorptivity was determined from FT-IR measurement data of the low molecular weight model compound.

TABLE 2

(melting point)

The melting point was determined from the melting curve peak generated during the 2 nd heating process by performing the 1 st heating from 200℃to 350℃at a heating rate of 10℃per minute using a differential scanning calorimeter (trade name: X-DSC7000, manufactured by Hitachi High-Tech Science Co., ltd.), then cooling from 350℃to 200℃at a cooling rate of 10℃per minute, and performing the 2 nd heating from 200℃to 350℃again at a heating rate of 10℃per minute.

Example 1

After adding 49.0L of pure water to a 174L-volume autoclave and sufficiently performing nitrogen substitution, 40.7kg of perfluorocyclobutane, 1.27kg of perfluoro (propyl vinyl ether) (PPVE) and 2.88kg of methanol were added, and the temperature in the system was kept at 35℃and the stirring speed was kept at 200rpm. Subsequently, tetrafluoroethylene (TFE) was introduced under pressure to 0.64MPa, and then 0.041kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was introduced to start polymerization. Since the pressure in the system decreased as polymerization proceeded, TFE was continuously fed so that the pressure became constant, and 0.045kg of PPVE was added to each 1kg of TFE fed, and polymerization was continued for 17.5 hours. TFE was discharged, and after the autoclave was allowed to return to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 30kg of powder.

The obtained powder was melt-extruded at 360℃by a screw extruder (trade name: PCM46, manufactured by Mitsui Co., ltd.) to obtain pellets of TFE/PPVE copolymer. Using the pellets obtained, the PPVE content was determined by the method described above. The results are shown in Table 3.

The obtained pellets were placed in a vacuum vibration type reaction apparatus VVD-30 (manufactured by Dachuan origin Co., ltd.) and heated to 210 ℃. After evacuation, N for introduction ₂ F gas dilution to 20 vol% ₂ The gas is brought to atmospheric pressure. From F ₂ After 0.5 hour from the time of gas introduction, the mixture was once evacuated and F was introduced again ₂ And (3) gas. After 0.5 hour, the mixture was again evacuated and F was introduced again ₂ And (3) gas. Thereafter, F is as described above ₂ The gas introduction and evacuation operations were continued for 1 time within 1 hour, and the reaction was carried out at 210℃for 10 hours. After the reaction, the inside of the reactor was fully replaced with N ₂ And (3) ending the fluorination reaction by using the gas. Using the fluorinated pellets, various physical properties were measured by the above-described method. The results are shown in Table 3.

Example 2

Fluorinated pellets were obtained in the same manner as in example 1, except that PPVE was changed to 1.33kg, methanol was changed to 3.03kg, and PPVE was changed to 0.046kg added per 1kg of TFE supplied. The results are shown in Table 3.

Example 3

Fluorinated pellets were obtained in the same manner as in example 1 except that PPVE was changed to 1.38kg, methanol was changed to 3.26kg, and PPVE was changed to 0.047kg added per 1kg of TFE supplied. The results are shown in Table 3.

Example 4

Fluorinated pellets were obtained in the same manner as in example 1, except that PPVE was changed to 1.44kg, methanol was changed to 3.53kg, PPVE was changed to 0.048kg added per 1kg of TFE supplied, and the polymerization time was changed to 18 hours. The results are shown in Table 3.

Example 5

Fluorinated pellets were obtained in the same manner as in example 1, except that PPVE was changed to 1.50kg, methanol was changed to 2.75kg, PPVE was changed to 0.049kg added per 1kg of TFE supplied, the polymerization time was changed to 18 hours, the temperature of the vacuum vibration reactor was changed to 170 ℃, and the reaction was changed to 5 hours at a temperature of 170 ℃. The results are shown in Table 3.

Comparative example 1

Fluorinated pellets were obtained in the same manner as in example 1 except that 34.0L of pure water, 30.4kg of perfluorocyclobutane, 0.86kg of PPVE, 1.50kg of methanol, 0.60MPa of TFE, 0.060kg of 50% methanol solution of di-n-propyl peroxydicarbonate, 0.046kg of PPVE was added to each 1kg of TFE, 21 hours of polymerization time, 160 ℃ of temperature rise of the vacuum vibration reactor, and 5 hours of reaction at 160 ℃. The results are shown in Table 3.

Comparative example 2

An unfluorinated pellet was obtained in the same manner as in example 1, except that PPVE was changed to 1.44kg, methanol was changed to 3.81kg, and PPVE was changed to 0.048kg added per 1kg of TFE supplied. The results are shown in Table 3.

Comparative example 3

After filling a 174L autoclave with 51.8L of pure water and sufficiently replacing the pure water with nitrogen, 40.9kg of perfluorocyclobutane, 1.79kg of perfluoro (propyl vinyl ether) (PPVE) and 6.61kg of methanol were charged, the temperature in the system was kept at 35℃and the stirring speed was kept at 200rpm. Subsequently, tetrafluoroethylene (TFE) was introduced under pressure to 0.64MPa, and then 0.051kg of a 50% methanol solution of di-n-propyl peroxydicarbonate was introduced to start polymerization. Since the pressure in the system decreased as polymerization proceeded, TFE was continuously fed so that the pressure became constant, and 0.042kg of PPVE was additionally fed per 1kg of TFE fed. When the additional amount of TFE fed reached 40.9kg, polymerization was terminated. Unreacted TFE was discharged, and after the autoclave was allowed to return to atmospheric pressure, the obtained reaction product was washed with water and dried to obtain 41.0kg of powder.

Using the obtained powder, a fluorination reaction was performed in the same manner as in example 1 to obtain fluorinated pellets. The results are shown in Table 3.

Comparative example 4

Fluorinated pellets were obtained in the same manner as in comparative example 3, except that PPVE was changed to 2.24kg, methanol was changed to 4.25kg, and additional feeding of 0.049kg was performed for each 1kg of TFE fed. The results are shown in Table 3.

Comparative example 5

Fluorinated pellets were obtained in the same manner as in comparative example 3 except that PPVE was changed to 2.53kg, methanol was changed to 4.78kg, and PPVE was changed to a dry powder of 41.0kg obtained by adding 0.055kg per 1kg of TFE supplied. The results are shown in Table 3.

TABLE 3

TABLE 3 Table 3

The expression "< 6" in Table 3 means that the number of functional groups is less than 6.

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

(reagent impregnation crack test)

About 50g of the pellets were put into a mold (inner diameter: 120mm, height: 38 mm), heated at 360℃for 20 minutes by a hot plate press, and then water-cooled while being pressurized under a pressure of 1MPa, to prepare a molded article having a thickness of about 2 mm. The resulting sheet was die cut using 13.5mm by 38mm rectangular dumbbell, thereby obtaining 3 test pieces. A notch was cut into the center of the long side of each test piece obtained by using a blade of 19mm X0.45 mm according to ASTM D1693. In a 100mL polypropylene bottle, 3 notched test pieces and 25g of a 40% by mass aqueous solution of tetrabutylammonium hydroxide were placed, and the notched test pieces were taken out after heating at 90℃for 20 hours in an electric furnace. The obtained 3 notched test pieces were mounted on a stress crack test jig according to ASTM D1693, heated in an electric furnace at 150 ℃ for 24 hours, visually inspected for notches and the periphery thereof, and the number of cracks was counted.

O: the number of cracks is 0

X: the number of cracks is 1 or more

(vapor permeability)

A sheet-like test piece having a thickness of about 0.2mm was produced using the pellets and a hot press molding machine. In a test cup (permeation area 12.56 cm) ² ) The inside was filled with 18g of water, covered with a sheet-like test piece, and fastened and sealed with a PTFE gasket interposed therebetween. The sheet-like test piece was brought into contact with water, kept at a temperature of 95℃for 30 days, taken out, left at room temperature for 2 hours, and then the mass reduction was measured. The water vapor permeability (g.cm/m) was measured by the following formula ² )。

Water vapor permeability (g.cm/m) ² ) =mass reduction amount (g) ×thickness (cm)/transmission area (m) of sheet-like test piece ² )

(storage modulus (E')

The dynamic viscoelasticity was measured by using DVA-220 (manufactured by IT meter control Co.). As a sample test piece, a hot press molded piece having a length of 25mm, a width of 5mm and a thickness of 0.2mm was used, and the storage modulus (MPa) at 150℃was measured in a range of 30℃to 250℃under a temperature rising rate of 2℃per minute and a frequency of 10 Hz.

(recovery amount)

Determination of recovery according to ASTM D395 or JIS K6262: 2013.

About 2g of the pellets were put into a mold (inner diameter: 13mm, height: 38 mm), melted at 370℃for 30 minutes by a hot plate press, and then water-cooled while being pressurized with a pressure of 0.2MPa (resin pressure), to prepare a molded article having a height of about 8 mm. Thereafter, the obtained molded article was cut to prepare a test piece having an outer diameter of 13mm and a height of 6 mm. The test piece thus produced was compressed to a compression set of 50% at normal temperature (i.e., a test piece having a height of 6mm was compressed to a height of 3 mm) using a compression device. The compressed test piece was left standing in an electric furnace in a state of being fixed to a compression device, and left standing at 150℃for 18 hours. The compression device was taken out of the electric furnace, cooled to room temperature, and then the test piece was taken out. After the recovered test piece was left at room temperature for 30 minutes, the height of the recovered test piece was measured, and the recovery amount was determined by the following formula.

Amount of recovery (mm) =t ₂ －t ₁

t ₁ : height of spacer (mm)

t ₂ : height (mm) of test piece removed from compression device

In the above test, t ₁ ＝3mm。

(sealing pressure at 150 ℃ C.)

The 150℃seal pressure was determined by the following formula from the results of the 150℃compression set test and the results of the 150℃storage modulus measurement.

Sealing pressure (MPa) at 150 ℃ = (t) ₂ －t ₁ )/t ₁ ×E’

t ₁ : height of spacer (mm)

t ₂ : height (mm) of test piece removed from compression device

E': storage modulus (MPa) at 150 DEG C

(haze value)

Sheets having a thickness of about 1.0mm were produced using pellets and a hot press molding machine. The sheet was immersed in a quartz dish containing pure water according to JIS K7136 using a haze meter (trade name: NDH7000SP, manufactured by Nippon Denshoku Kogyo Co., ltd.) to measure the haze value.

(injection moldability)

Condition

The copolymer was injection molded using an injection molding machine (manufactured by Sumitomo mechanical industries Co., ltd., SE50 EV-A) at Sup>A cylinder temperature of 390 ℃, sup>A mold temperature of 220 ℃ and an injection speed of 100 mm/s. As the mold, a mold (4 cavities, side gates of 15mm×15mm×1 mmt) in which Cr plating was performed on HPM38 was used. The 4 injection molded articles thus obtained were observed and evaluated according to the following criteria. The presence or absence of surface roughness was confirmed by contacting the surface of the injection-molded article.

3: the surfaces of the 4 molded articles were entirely smooth.

2: for 1 of the 4 molded articles, roughness was confirmed on the surface within 1cm from the position where the gate of the mold was located.

1: for 2 to 4 of the 4 molded articles, roughness was confirmed on the surface within 1cm from the position where the gate of the mold was located.

0: roughness was confirmed on the entire surface of 4 molded articles.

(tensile Strength at 150 ℃ C. (TS))

Tensile strength at 150℃was measured according to ASTM D638.

(electrolyte impregnation test)

About 5g of pellets were put into a mold (inner diameter: 120mm, height: 38 mm), melted at 370℃for 20 minutes by a hot plate press, and then water-cooled while being pressurized by a pressure of 1MPa (resin pressure), to prepare a molded article having a thickness of about 0.2 mm. Thereafter, using the obtained molded article, a 15mm square test piece was produced.

To a 20mL glass sample bottle, 10 pieces of the obtained test piece and 2g of dimethyl carbonate (DMC) were added, and the cap of the sample bottle was closed. The sample bottles were placed in a constant temperature bath at 80℃for 144 hours, whereby the test pieces were immersed in DMC. Then, the sample bottle was taken out of the incubator, cooled to room temperature, and then the test piece was taken out of the sample bottle. DMC remaining after the test piece was taken out was air-dried in a room at 25℃for 24 hours in a state of being placed in a sample bottle, and 2g of ultrapure water was added. The resulting aqueous solution was transferred to a cell of an ion chromatography system, and the fluorine ion content of the aqueous solution was measured by the ion chromatography system (Dionex ICS-2100, manufactured by Thermo Fisher Scientific Co.).

(mold Corrosion test)

20g of pellets were placed in a glass vessel (50 ml screw tube), and a metal column (5 mm square, 30mm in length) formed of HPM38 (Cr-plated) or HPM38 (Ni-plated) was suspended in the glass vessel so as not to contact the pellets. The glass container was then covered with aluminum foil. The glass container was put in an oven in this state and heated at 380℃for 3 hours. Then, the heated glass vessel was taken out of the oven, cooled to room temperature, and the degree of corrosion of the metal column surface was visually observed. The degree of corrosion was determined according to the following criteria.

O: no corrosion was observed

Delta: corrosion was slightly observed

X: corrosion was observed

(coating break and spark)

By means ofA wire coating molding machine (manufactured by Takara Shuzo Co., ltd.) extruded a coating copolymer onto a copper conductor having a conductor diameter of 0.50mm at the coating thickness described below to obtain a coated wire. The wire coating extrusion molding conditions were as follows.

a) Core conductor: conductor diameter 0.50mm

b) Coating thickness: 0.15mm

c) Coated wire diameter: 0.80mm

d) Wire drawing speed: 150 m/min

e) Extrusion conditions:

single screw extrusion moulding machine with cylinder shaft diameter=30 mm, L/d=22

Die (inner diameter)/chip (outer diameter) =8.0 mm/5.0mm

Set temperature of extruder: barrel section C-1 (330 ℃), barrel section C-2 (360 ℃), barrel section C-3 (375 ℃), head section H (390 ℃), die section D-1 (405 ℃) and die section D-2 (395 ℃). The core wire preheating was set at 80 ℃.

(spark)

A spark tester (DENSOK HIGH FREQ SPARK TESTER) was provided on-line on the wire coating, and the presence or absence of damage to the wire coating was evaluated at a voltage of 1500V. The molding was continued for 1 hour, and the case where the spark was zero was found to be acceptable (o), and the case where the spark was detected to be unacceptable (x).

(coating off)

The coating molding of the electric wire was continuously performed, and the case where the coating was broken 1 or more times within 1 hour was regarded as discontinuous molding (x), and the case where the coating was not broken was regarded as continuous molding (o).

(core wire Corrosion test)

By means ofA wire coating molding machine (manufactured by Takara Shuzo Co., ltd.) extruded a coating copolymer onto a conductor having a conductor diameter of 0.812mm at the following coating thickness to obtain a coated wire. The wire coating extrusion molding conditions were as follows. />

a) Core conductor: soft wire conductor diameter 0.812mm (AWG 20)

b) Coating thickness: 0.9mm

c) Coated wire diameter: 2.6mm

d) Wire drawing speed: 3 m/min

e) Extrusion conditions:

single screw extrusion moulding machine with barrel shaft diameter=30mm, l/d=22

Die (inner diameter)/sheet (outer diameter) =26.0 mm/8.0mm

Set temperature of extruder: barrel section C-1 (330 ℃), barrel section C-2 (350 ℃), barrel section C-3 (370 ℃), head section H (380 ℃), die section D-1 (380 ℃) and die section D-2 (380 ℃). The core wire preheating was set at 80 ℃.

The coated wire molded under the above molding conditions was cut into a length of 20cm, left to stand in a constant temperature and humidity tank (Junior SD-01 manufactured by FATC corporation) at 60 ℃ and a humidity of 95% for 2 weeks, and then the coating layer was peeled off to expose the conductor, and the surface of the conductor was visually observed and evaluated according to the following criteria.

O: no corrosion was observed

X: corrosion was observed

(abrasion test)

Using the pellets and a hot press molding machine, a sheet-like test piece having a thickness of about 0.2mm was produced, from which a 10 cm. Times.10 cm test piece was cut. The test piece thus prepared was fixed on a test stand of a taber abrasion tester (No. 101 model taber abrasion tester, manufactured by An Tian refiner manufacturing company), and abrasion test was performed using the taber abrasion tester under conditions of a test piece surface temperature of 90 ℃, a load of 500g, an abrasion wheel CS-10 (20 revolutions ground with grinding paper # 240), and a rotational speed of 60 rpm. The test piece weight after 1000 revolutions was measured, and the test piece weight was further measured after 3000 revolutions with the same test piece. The abrasion loss was determined by the following formula.

Abrasion loss (mg) =m1-M2

M1: test piece weight after 1000 revolutions (mg)

M2: test piece weight after 3000 revolutions (mg)

(air permeability coefficient)

A sheet-like test piece having a thickness of about 0.1mm was produced using the pellets and a hot press molding machine. Using the obtained test piece, the test piece was prepared according to JIS K7126-1:2006, air permeability was measured using a differential pressure type gas permeability meter (L100-5000 type gas permeability meter, manufactured by Systemech ilinois Co.). Obtaining a permeation area of 50.24cm ² The air permeability at a test temperature of 70℃and a test humidity of 0% RH. Using the obtained air permeability and the test piece thickness, the air permeability coefficient was calculated by the following formula.

Air permeability coefficient (cm) ³ ·mm/(m ² ·24h·atm))＝GTR×d

GTR: air permeability (cm) ³ /(m ² ·24h·atm))

d: test piece thickness (mm)

(electrolyte permeability)

A sheet-like test piece having a thickness of about 0.2mm was produced using the pellets and a hot press molding machine. In a test cup (permeation area 12.56 cm) ² ) 10g of dimethyl carbonate (DMC) was placed therein, covered with a sheet-like test piece, and fastened and sealed with a PTFE gasket interposed therebetween. The pellet was allowed to contact DMC, kept at 60℃for 30 days, and then taken out, and left at room temperature for 1 hour to measure the mass reduction. The DMC permeability (g.cm/m) was determined by ² )。

Electrolyte permeability (g.cm/m) ² ) =mass reduction amount (g) ×thickness (cm)/transmission area (m) of sheet-like test piece ² )

(methyl ethyl ketone (MEK) transmittance)

A sheet-like test piece having a thickness of about 0.1mm was produced using the pellets and a hot press molding machine.In a test cup (permeation area 12.56 cm) ² ) 10g of MEK was placed in the container, and the container was covered with a sheet-like test piece, and fastened and sealed with a PTFE gasket interposed therebetween. The sheet-like test piece was brought into contact with MEK, kept at a temperature of 60℃for 60 days, taken out, left at room temperature for 1 hour, and then the mass reduction was measured. The MEK transmittance (mg.cm/m) was determined by the following formula ² Day).

MEK transmittance (mg cm/m) ² Day) = [ mass reduction (mg) ×thickness (cm) of sheet-like test piece]Transmission area (m) ² ) Days (Tian)]

(110 ℃ C. Load deflection rate)

Using the pellets and a hot press molding machine, a sheet-like test piece having a thickness of about 4.2mm was produced, from which a test piece having a thickness of 80X 10mm was cut, and heated at 100℃for 20 hours by an electric furnace. The test was carried out using a thermal deformation tester (manufactured by An Tian refiner) according to the method described in JIS K-K7191, except for the test piece obtained, under conditions of a test temperature of 30 to 150 ℃, a temperature rising rate of 120 ℃/hr, a bending stress of 1.8MPa, and a flat-bed (flat-bed) method. The load deflection was obtained by the following method. The sheet having a small flexural modulus under load at 110 ℃ has excellent rigidity at a high temperature of 110 ℃.

Load deflection (%) =a2/a1×100

a1: thickness of test piece before test (mm)

a2: deflection (mm) at 110 DEG C

(tensile creep test)

The tensile creep strain was measured using TMA-7100 manufactured by Hitachi high technology Co. Using the pellets and a hot press molding machine, a sheet having a thickness of about 0.1mm was produced, and a sample having a width of 2mm and a length of 22mm was produced from the sheet. The sample was mounted to the measuring jig at a distance of 10mm from the jig. For the sample, the cross-sectional load was 2.41N/mm ² The sample was subjected to a load of 240℃and the displacement (mm) of the length of the sample was measured from the time point 90 minutes after the start of the test to the time point 300 minutes after the start of the test, and the ratio (tensile creep strain (%)) of the displacement (mm) of the length to the initial sample length (10 mm) was calculated. Sheet with small tensile creep strain (%) measured at 240℃for 300 minutes even in a very high temperature environmentThe load tensile load is not easy to elongate, and the high-temperature tensile creep property is excellent.

(dielectric loss tangent)

The pellets were melt-molded to prepare a cylindrical test piece having a diameter of 2 mm. The test piece thus fabricated was set in a cavity resonator for 6GHz manufactured by kanto electronics application development company, and measured by a network analyzer manufactured by agilent technologies. The measurement result was analyzed by analysis software "CPMA" manufactured by Kanto electronic application development Co., ltd. On a personal computer connected to the network analyzer, to thereby determine the dielectric loss tangent (tan. Delta.) at 20℃and 6 GHz.

TABLE 4

Claims

1. A copolymer comprising tetrafluoroethylene units and perfluoro (propyl vinyl ether) units,

the content of perfluoro (propyl vinyl ether) unit is 4.2 to 4.9 mass% relative to the total monomer units,

the melt flow rate at 372 ℃ is 19.0g/10 min-27.0 g/10 min,

the number of functional groups per 10 ⁶ The number of carbon atoms of the main chain is 50 or less.

2. The copolymer of claim 1, wherein the melt flow rate at 372 ℃ is from 20.0g/10 min to 25.0g/10 min.

3. The copolymer according to claim 1 or 2, wherein the number of functional groups is relative to 10 per unit ⁶ The number of carbon atoms of the main chain is 20 or less.

4. An injection molded article comprising the copolymer according to any one of claims 1 to 3.

5. A coated electric wire comprising a coating layer comprising the copolymer according to any one of claims 1 to 3.

6. A molded article comprising the copolymer according to any one of claims 1 to 3, wherein the molded article is a valve, a gasket, a filter cover, a joint or a wire coating.