Solid substance, molded body, method for producing solid substance

Abstract

An object of the present invention is to provide a solid substance, a molded article, and a method for producing the solid substance, which can form a molded article having excellent ozone resistance and is less likely to generate cracks and blisters due to ozone. 【Solution means】The solid substance of the present invention is a powdery or pelletized solid substance containing a copolymer containing a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by the formula (1) (CF2=CF-O-Rf), wherein the total number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH is less than 150 per 10 main chain carbons of the copolymer, and the outgas generation amount when the solid substance is heated at 300 ° C for 120 minutes is 100 mass ppb or less with respect to the total mass of the solid substance in terms of n-hexane. 6 per, and the outgas generation amount when the solid substance is heated at 300 ° C for 120 minutes is 100 mass ppb or less with respect to the total mass of the solid substance in terms of n-hexane.

Description

Technical Field

[0001] The present invention relates to a solid material, a molded article, and a method for producing a solid material.

Background Art

[0002] As a fluororesin having excellent mechanical properties, chemical properties, electrical properties, etc. and being capable of melt processing, a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PFA") is known. For example, Patent Document 1 discloses a molding material for an ozone-resistant article made of a copolymer composed of tetrafluoroethylene and perfluorovinyl ether.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Recently, when a molded article of PFA is used as a pipe material for a semiconductor manufacturing apparatus, further improvement in ozone resistance is required for the molded article. When the present inventors evaluated a molded article formed using the PFA described in Patent Document 1, they found that the ozone resistance did not meet the higher required level currently demanded and further improvement was necessary.

[0005] An object of the present invention is to provide a solid material capable of forming a molded article excellent in ozone resistance in which cracks and blisters due to ozone are hardly generated, in view of the above problems. Another object of the present invention is also to provide a method for producing a molded article and a solid material.

Means for Solving the Problems

[0006] As a result of intensive studies on the above problems, the present inventors have found that a solid in powder or pellet form containing a copolymer comprising a unit A based on tetrafluoroethylene and a unit B based on a compound represented by a specific formula (1), wherein the total number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH in the copolymer is less than 150 per 10 carbon atoms of the copolymer 6 and the outgas generation amount when the solid is heated to 300 °C is 100 mass ppb or less with respect to the total mass of the solid in terms of n-hexane, and have found that a molded article excellent in ozone resistance can be formed by using such a solid, thus arriving at the present invention.

[0007] That is, the inventors have found that the above problems can be solved by the following configuration. 〔1〕 A solid in powder or pellet form containing a copolymer comprising a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by the following formula (1), wherein the total number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH is less than 150 per 10 main-chain carbon atoms of the copolymer 6 and the outgas generation amount when the solid is heated at 300 °C for 120 minutes is 100 mass ppb or less with respect to the total mass of the solid in terms of n-hexane. Solid. 〔2〕 The solid according to 〔1〕, wherein the content of the unit A is 97.00 to 99.50 mol% with respect to all units of the copolymer. 〔3〕 The solid according to 〔1〕, wherein the content of the unit B is 0.50 to 3.00 mol% with respect to all units of the copolymer. 〔4〕 The solid according to 〔1〕, wherein the melt flow rate of the copolymer measured under the conditions of a temperature of 372 °C and a load of 5 kg in accordance with ASTM D1238 is 1.0 to 50.0 g / 10 min. 〔5〕 The solid according to 〔1〕, wherein the unit B contains a unit based on perfluoro(propyl vinyl ether). 〔6〕 A molded article characterized by being obtained by molding the solid matter according to any one of 〔1〕 to 〔5〕. 〔7〕 A powdery or pelletized solid matter containing a copolymer containing a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by the following formula (1) is brought into flow contact with a fluorinating agent to reduce the total number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH in the copolymer, and the copolymer contains the unit A and the unit B, and the total number of the functional groups is less than 150 per 10 main chain carbons of the copolymer. A method for producing a solid matter, characterized by obtaining a powdery or pelletized solid matter containing the copolymer. 6 〔8〕 An inert gas is brought into flow contact with the solid matter that has been brought into flow contact with the fluorinating agent. 〔9〕 The amount of the inert gas brought into flow contact is 0.005 L / g or more in terms of the volume converted to the standard state per mass of the solid matter. The method for producing a solid matter according to 〔8〕. 〔10〕 The treatment temperature in the flow contact of the inert gas is 30 to 240 °C. The method for producing a solid matter according to 〔9〕. 〔11〕

Advantages of the Invention

[0008]

Modes for Carrying Out the Invention

[0009] The meanings of the terms in this specification are as follows. A numerical range represented by using "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0010] ​The term "unit" is a general term for an atomic group directly formed by polymerization of a monomer and derived from one molecule of the monomer, and an atomic group obtained by chemically converting a part of the atomic group. In the following, in some cases, the unit derived from each monomer is denoted by a name obtained by attaching "unit" to the monomer name. "Unit A" is a unit based on tetrafluoroethylene contained in the copolymer. "Unit B" is a unit based on the compound represented by the following formula (1) contained in the copolymer. Formula (1) CF2=CF-O-Rf Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms, and the perfluoroalkyl group may have an etheric oxygen atom between carbon atoms.

[0011] The "specific functional group" means a functional group contained in the group consisting of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH. The "number of functional groups" means the total number of specific functional groups that the copolymer has, unless otherwise specified.

[0012] "Solid matter" means a composition that is solid at 25°C. "Powdery solid matter" means an object having an average particle diameter of 3000 μm or less and a bulk density of 0.1 to 0.8 g / cm 3 . "Pellet-shaped solid matter" means a particulate molded product produced by a method of extruding and cutting a solid matter.

[0013] [First Embodiment: Solid Matter] The solid matter according to the first embodiment of the present invention (hereinafter also referred to as "this solid matter") contains unit A and unit B, and contains a copolymer (hereinafter also referred to as "this copolymer") having a specific functional group within a predetermined content range. When this solid matter is heated at 300°C for 120 minutes, the outgas generation amount is 100 mass ppb or less with respect to the total mass of this solid matter, in terms of n-hexane.

[0014] By using such a solid material, a molded article excellent in ozone resistance, in which cracks and blisters due to ozone hardly occur, can be formed. Although the details of the reason are not yet clear, it is presumed to be due to the following reasons. The outgas generation amount is the amount of gaseous substances derived from the solid material generated when the solid material is heated at 300 °C for 120 minutes. Here, examples of the components that are the sources of the gaseous substances include the end groups of the copolymer contained in the solid material, by-products and impurities of the fluorination treatment. It is presumed that these components are thermally decomposed during heating at 300 °C for 120 minutes to become gaseous substances. On the other hand, since ozone promotes the decomposition of organic substances due to its strong oxidizing power, the above components can be easily oxidized and decomposed by ozone even under low-temperature conditions, generating oxides such as carbon dioxide, which may cause cracks and foaming (blisters) on the surface of the molded article. In contrast, for a molded article formed using a solid material in which the outgas generation amount when heated at 300 °C for 120 minutes is below a predetermined value, it is presumed that oxidative decomposition upon contact with ozone can be suppressed, the generation of cracks and blisters due to ozone can be suppressed, and the ozone resistance can be improved. Also, it is presumed that when the total number of specific functional groups possessed by the copolymer is less than 150 per 10 6 carbon atoms in the main chain of the copolymer, oxidative decomposition of the specific functional groups by ozone can be suppressed. Thus, it is presumed that a molded article excellent in ozone resistance is obtained by satisfying each requirement.

[0015] The content of the present copolymer in the solid material is preferably 70% by mass or more and 100% by mass or less, more preferably 90% by mass or more and less than 100% by mass, and still more preferably 99% by mass or more and less than 100% by mass, based on the total mass of the solid material. When the content of the present copolymer is within the above range, it is easy to produce a molded article excellent in ozone resistance from the solid material.

[0016] <The present copolymer> The present copolymer contains at least unit A and unit B.

[0017] The content of unit A is preferably 97.00 to 99.50 mol%, more preferably 97.50 to 99.50 mol%, still more preferably 98.00 to 99.50 mol% based on all the units contained in the present copolymer in terms of better heat resistance.

[0018] Unit B is a unit based on the monomer represented by the following formula (1). CF2=CF-O-Rf (1) In formula (1), Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms, and the perfluoroalkyl group may have an etheric oxygen atom between carbon atoms. The number of carbon atoms of the perfluoroalkyl group represented by Rf is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3 from the viewpoint of better polymerization reactivity. The perfluoroalkyl group may be linear or branched. When the perfluoroalkyl group has an etheric oxygen atom between carbon atoms, the number of etheric oxygen atoms is preferably 1 to 3, more preferably 1 or 2. The perfluoroalkyl group preferably has no etheric oxygen atom.

[0019] Specific examples of the monomer represented by formula (1) include perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE), and perfluoro(propyl vinyl ether) (PPVE), with PMVE or PPVE being preferred and PPVE being more preferred.

[0020] The content of unit B is preferably 0.50 to 6.0 mol%, more preferably 0.50 to 3.00 mol%, still more preferably 1.00 to 3.00 mol%, and particularly preferably 1.50 to 3.00 mol% based on all the units contained in the present copolymer in terms of better molding processability, flex resistance, and surface smoothness. The present copolymer may contain two or more types of unit B. When the present copolymer contains two or more types of unit B, it means that the total content of the two or more types of unit B is within the above range.

[0021] In this copolymer, the total content of unit A and unit B is preferably 97.50 to 100.00 mol%, more preferably 99.00 to 100.00 mol%, still more preferably 99.50 to 100.00 mol%, based on all the units contained in the copolymer, from the viewpoint that the resulting molded article is not easily deformed by compression or tension.

[0022] In addition to unit A and unit B, this copolymer may contain units based on other monomers copolymerizable with TFE and the monomer represented by formula (1). Examples of other monomers include ethylene, vinylidene fluoride (VdF), hexafluoropropylene (HFP), CX 1 X 2 =CX 3 (CF2) n X 4 (wherein X 1 、X 2 and X 3 each independently represents a hydrogen atom or a fluorine atom, X 4 represents a hydrogen atom, a fluorine atom or a chlorine atom, and n represents an integer of 1 to 10.), and monomers represented by CF2=CF-OCH2-Rf 2 (wherein Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms). When this copolymer contains units based on other monomers, the content of the units based on other monomers is preferably less than 2.50 mol%, more preferably less than 1.00 mol%, still more preferably less than 0.50 mol%, based on all the units contained in the copolymer.

[0023] From the viewpoint of more excellent abrasion resistance during repeated use, it is preferable that this copolymer does not contain units based on the above-mentioned other monomers and contains only unit A and unit B. In this case, the total content of unit A and unit B is 100.00 mol% based on all the units contained in the copolymer.

[0024] The content of each of unit A, unit B and the units based on other monomers in this copolymer is 19 measurable by a known method such as the F-NMR (nuclear magnetic resonance analysis) method.

[0025] (Number of functional groups) In this copolymer, the total number of specific functional groups included in the group consisting of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH is such that per 10 carbon atoms of the copolymer 6 is less than 150. From the viewpoint of forming a molded article with more excellent ozone resistance, the number of functional groups is preferably 50 or less, more preferably 20 or less, and still more preferably 10 or less. The number of functional groups may be 0.

[0026] The specific functional groups are functional groups present at the main chain terminal or side chain terminal of the copolymer, and functional groups present in the main chain or side chain, and the number of functional groups is the total number of the specific functional groups. The specific functional groups are introduced into the copolymer, for example, by a chain transfer agent or a polymerization initiator used in the production of the copolymer. More specifically, when an alcohol is used as the chain transfer agent, or when a peroxide having a -CH2OH structure is used as the polymerization initiator, -CH2OH is introduced at the main chain terminal of the copolymer. Also, by polymerizing a monomer having a functional group, the above functional group is introduced at the side chain terminal of the copolymer. Also, when the number of functional groups of the copolymer having specific functional groups exceeds a predetermined range, the copolymer can be fluorinated and the specific functional groups can be converted to -CF3 end groups to reduce the number of functional groups. By changing the conditions (for example, treatment time, etc.) of the fluorination treatment described later, the number of functional groups of the copolymer can be adjusted.

[0027] Infrared spectroscopy can be used for the identification of the types of functional groups and the measurement of the number of functional groups in the copolymer. Specifically, the number of functional groups is measured by the following method. First, the copolymer is molded by a hot press at 330 °C to produce a film with a thickness of 0.30 to 0.35 mm. This film is analyzed by Fourier transform infrared spectroscopy to obtain the infrared absorption spectrum of the copolymer. Separately, an infrared absorption spectrum (base spectrum) that is completely fluorinated and has no specific functional groups is obtained, and a difference spectrum between the infrared absorption spectrum of the copolymer and the base spectrum is obtained. From the absorption peak of the specific functional group appearing in this difference spectrum, according to the following formula (A), the number of functional groups N per 10 carbon atoms in the copolymer is calculated. 6 per is calculated.

[0028] N = I × K / t (A) I: Absorbance K: Correction coefficient t: Thickness of the film (mm)

[0029] Table 1 shows the absorption frequency, molar extinction coefficient, and correction coefficient for specific functional groups. The molar extinction coefficient of the specific functional group is determined from the FT-IR (Fourier transform infrared spectroscopy) measurement data of the low molecular weight model compound.

[0030]

Table 1

[0031] In the copolymer, the absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are several tens of wavenumbers (cm -1 ) lower than the respective absorption frequencies of -CF2H, -COF, -COOH (free and bonded), -COOCH3, and -CONH2 shown in the table. For example, the number of -COF is the sum of the number of functional groups determined from the absorption peak at the absorption frequency of 1883 cm -1 attributed to -CF2COF and the number of functional groups determined from the absorption peak at the absorption frequency of 1840 cm -1 attributed to -CH2COF.

[0032] (Melt Flow Rate) The MFR of this copolymer is preferably 1.0 to 50.0 g / 10 min, more preferably 3.0 to 45.0 g / 10 min, and even more preferably 5.0 to 40.0 g / 10 min, from the viewpoint that a molded article having excellent balance between folding resistance and bending strength can be formed. As a specific example of the method for making the MFR of this copolymer within the above range, a method for adjusting the molecular weight of this copolymer can be mentioned. The larger the molecular weight of this copolymer, the smaller the MFR. The MFR of the copolymer means the mass (g) of the copolymer flowing out from an orifice with a diameter of 2 mm and a length of 8 mm in 10 minutes, measured under the conditions of a temperature of 372 °C and a load of 5 kg in accordance with ASTM D1238. Note that since the copolymer is the main component of the solid matter and the influence of components other than the copolymer on the measurement of MFR is almost negligible, the measured value of MFR obtained by measuring the solid matter can be regarded as the MFR of the copolymer.

[0033] (Melting Point) The melting point of this copolymer is preferably 298.0 °C or higher, more preferably 299.0 °C or higher, and even more preferably 300.0 °C or higher. The melting point of this copolymer is preferably 310.5 °C or lower, more preferably 310.0 °C or lower, and even more preferably 309.5 °C or lower, from the viewpoint that the low-speed tear strength of the molded article is excellent. As a specific example of the method for making the melting point of this copolymer within the above range, a method for lowering the polymerization temperature during the production of this copolymer can be mentioned. The melting point of this copolymer is the temperature corresponding to the endothermic peak when the copolymer is heated, with the temperature rising at 10 °C / min in an air atmosphere using a differential scanning calorimeter.

[0034] This solid matter may contain other components other than those described above. Specific examples of such other components include other resins other than this copolymer, heat stabilizers, antioxidants, colorants, ultraviolet absorbers, fillers, crosslinking agents, crosslinking aids, and organic peroxides. When the solid contains other components, the content of the other components is preferably 0.0000001 to 5 parts by mass, more preferably 0.0000005 to 3 parts by mass, and even more preferably 0.000001 to 1 part by mass with respect to 100 parts by mass of the copolymer.

[0035] The solid may be in powder form or pellet form. The powdered solid has an average particle diameter of 3000 μm or less and a bulk density of 0.1 to 0.8 g / cm 3 of particles. In this specification, the bulk density is measured in accordance with JIS K-5101-12-1:2004 and is also referred to as apparent density or loose bulk density. Specifically, a bulk density measuring device (for example, manufactured by Kuramoto Scientific Instruments Co., Ltd.) is placed on an electronic balance (for example, "EK-1200A" manufactured by A&D Co., Ltd., etc.), and the sample to be measured is put into the bulk density measuring device using a funnel. Then, after removing the sample that has overflowed from the opening surface by scraping it flat along the opening surface of the bulk density measuring device, the weight of the sample is measured, and the bulk density is calculated by dividing the obtained weight by the internal volume of the measuring device. Also, the average particle diameter is measured using a laser diffraction / scattering particle size distribution measuring device (for example, "LA-960V2" manufactured by Horiba, Ltd., etc.). Specifically, wet measurement is performed by dispersing the sample in an isopropanol solvent and measuring the average particle diameter, and the average particle diameter is calculated. The solid may be primary particles or secondary particles formed by aggregation of primary particles.

[0036] When the solid is in pellet form, a particulate molded body with a diameter or length of about 1 to 10 mm of the solid is preferred. The shape of the pellet-shaped solid is not limited, but is usually spherical, ellipsoidal, or cylindrical.

[0037] (Outgassing amount) The outgassing amount when the solid is heated at 300 °C for 120 minutes is 100 mass ppb or less with respect to the total mass of the solid, in terms of n-hexane. The amount of outgas generated when the solid is heated at 300°C for 120 minutes can be measured using a headspace GC-MS (HS-GC-MS) apparatus. Details of the method for measuring outgas derived from the solid generated when the solid is heated to 300°C using the HS-GC-MS apparatus and the method for converting the measured amount of outgas to the amount of n-hexane are described in the examples below. When a molded body is produced using this solid, the heating time during molding is usually extremely short compared to the heating time when measuring the amount of outgas generated. Therefore, thermal decomposition of the end groups of the copolymer hardly occurs during the production of the molded body.

[0038] From the viewpoint of forming a molded body with more excellent ozone resistance, the amount of outgas generated, converted to the above n-hexane, is preferably less than 50 mass ppb, more preferably less than 25 mass ppb, based on the total mass of the solid. The amount of outgas generated may be 0 mass ppb based on the total mass of the solid.

[0039] When the amount of outgas generated by the solid exceeds a predetermined range, the amount of outgas generated can be reduced by performing a process of flowing and contacting a fluorinating agent with the solid containing the copolymer as a fluorination treatment of the copolymer. The process of flowing and contacting a fluorinating agent with the solid will be described later.

[0040] In this solid, from the viewpoint that the molded body formed from this solid is likely to have excellent crack resistance, the content of the second copolymer containing unit A and the unit based on hexafluoropropylene and not containing unit B is preferably less than 0.5 mass% with respect to the total of the content of this copolymer and the content of the second copolymer. From the viewpoint that the molded body formed from this solid is likely to have excellent crack resistance, the content of the second copolymer is more preferably 0 mass% with respect to the total of the content of this copolymer and the content of the second copolymer. Note that "not containing unit B" means that the content of unit B with respect to all units of the copolymer is 0.5 mol% or less.

[0041] <Method for producing solid> Examples of the method for producing the solid include a method in which a copolymer is produced and a fluorinating agent is passed through and brought into contact with the solid containing the copolymer to fluorinate the copolymer. Hereinafter, the method for producing the solid will be described by taking, as an example, a method in which a copolymer is produced and a fluorinating agent is passed through and brought into contact with the solid containing the produced copolymer as a fluorination treatment.

[0042] Examples of the step of producing the copolymer include steps of producing using the above monomers (TFE and the compound represented by formula (1)) by known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, and a step of producing by solution polymerization is preferred. In the production of the copolymer, in addition to the above monomers, a polymerization initiator, a polymerization medium, a chain transfer agent, etc. can be used.

[0043] The polymerization initiator is preferably a radical polymerization initiator having a half-life of 10 hours at a temperature of 0 to 100°C, and more preferably a radical polymerization initiator having the above temperature of 20 to 90°C. Specific examples of the polymerization initiator include various polymerization initiators exemplified in International Publication No. 2013 / 015202. The polymerization initiator may be used alone or in combination of two or more. The amount of the polymerization initiator used is preferably 0.01 to 0.9 parts by mass, and more preferably 0.05 to 0.5 parts by mass, based on 100 parts by mass of the amount of the monomers used.

[0044] Examples of the polymerization medium include water, an organic solvent, and a mixed solvent of water and an organic solvent. As the organic solvent, fluorine-based solvents such as perfluorocarbon, hydrofluorocarbon, and hydrofluoroether can be used. Specific examples of the organic solvent include the polymerization media exemplified in International Publication No. 2013 / 015202. As the polymerization medium, a polymerization medium containing water is preferred, and ultrapure water is more preferred.

[0045] The polymerization medium may be used alone or in combination of two or more. As the polymerization medium, a mixed solvent of water and a fluorine-based solvent is preferable, and a mixed solvent of water and a perfluorocarbon is more preferable. From the viewpoints of suspension and economy, the amount of the fluorine-based solvent used is preferably 10% by mass or more and less than 100% by mass based on the total mass of the mixed solvent. The amount of the polymerization medium used is preferably 3 times or more and more preferably 5 times or more in terms of mass ratio with respect to the amount of the monomer used. Also, it is preferably 20 times or less and more preferably 17 times or less.

[0046] As the chain transfer agent, from the viewpoints of a large chain transfer constant and a small addition amount, alcohols such as methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3,3-hexafluoroisopropanol, and 2,2,3,3,3-pentafluoropropanol; hydrocarbons such as n-pentane, n-hexane, and cyclohexane; hydrofluorocarbons such as CF2H2; ketones such as acetone; mercaptans such as methyl mercaptan; esters such as methyl acetate and ethyl acetate; and ethers such as diethyl ether and methyl ethyl ether are preferable. Among them, at least one selected from the group consisting of alcohols, hydrocarbons, and hydrofluorocarbons is preferable, at least one selected from the group consisting of alcohols and hydrocarbons is more preferable, and alcohols are even more preferable from the viewpoints of a higher chain transfer constant and higher stability of the end groups of the copolymer. As the alcohols, methanol or ethanol is preferable, and methanol is more preferable from the viewpoints of reactivity and availability. Two or more chain transfer agents may be used. The amount of the chain transfer agent used is preferably 0.001 times or more and more preferably 0.005 times or more in terms of mass ratio with respect to the amount of the monomer used. Also, it is preferably 5 times or less and more preferably 4 times or less.

[0047] The polymerization temperature is preferably 15 to 60 °C, more preferably 20 to 58 °C, and even more preferably 25 to 55 °C. If the polymerization temperature is 15 °C or higher, the polymerizability can be excellent. If the polymerization temperature is 60 °C or lower, it is easy to reduce the number of unstable terminal groups of the copolymer. The polymerization pressure is preferably 0.5 to 3.0 MPa, more preferably 0.9 to 2.5 MPa. The polymerization time is preferably 1 to 12 hours.

[0048] When an aqueous dispersion containing a copolymer is obtained by polymerization, the copolymer contained in the aqueous dispersion can be recovered by coagulating, washing, and drying it. Also, when the copolymer is obtained as a slurry by polymerization, the copolymer can be recovered by taking out the slurry from the reaction vessel, washing, and drying it.

[0049] The copolymer obtained by polymerization may be a powdery solid. Also, the recovered copolymer may be formed into a pellet-shaped solid by a known method.

[0050] The pellet-shaped solid can be formed by a conventionally known method. Examples of the method for forming the pellet-shaped solid include a method of extruding while melting a fluorinated copolymer using a single-screw extruder, a twin-screw extruder, and a tandem extruder, and cutting it into a predetermined length to form pellets.

[0051] The extrusion temperature in melt extrusion is appropriately changed depending on the melt viscosity of the copolymer and the production method, but preferably the melting point of the copolymer + 20 °C to the melting point of the copolymer + 140 °C. As the method for cutting the copolymer, conventionally known methods such as a strand cut method, a hot cut method, an under-water cut method, and a sheet cut method can be adopted. The obtained pellets may be heated to remove volatile components in the pellets (degassing treatment). The obtained pellets may be treated by contacting them with warm water at 30 to 200 °C, steam at 100 to 200 °C, or warm air at 40 to 200 °C.

[0052] Alternatively, if necessary, the composition containing the copolymer obtained by polymerization may be pulverized to produce a powdery solid substance. Examples of the composition containing the copolymer include a granulated product containing the copolymer and a melt-kneaded product containing the copolymer. The pulverization can be carried out using a known pulverizer such as a rotor mill, a hammer mill, a turbo mill, or a jet mill.

[0053] (Fluorination treatment) Next, as the fluorination treatment, a treatment is performed in which a fluorinating agent is circulated and contacted with a powdery or pelletized solid substance containing the copolymer obtained by polymerization. By the fluorination treatment, specific functional groups of the copolymer, which consist of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, and -CF2H, can be converted to -CF3. Thereby, the number of specific functional groups can be reduced, and the number of functional groups of the copolymer can be adjusted within a predetermined range.

[0054] Furthermore, by circulating and contacting the fluorinating agent with the solid substance containing the copolymer, fluorination can be carried out while removing by-products and impurities generated by the fluorination treatment. Therefore, the outgas generation amount of the solid substance can be reduced, and a solid substance with an outgas generation amount within a predetermined range can be easily produced. As a specific method of circulating and contacting the fluorinating agent, a method of filling a powdery or pelletized solid substance into a flow-through column and circulating the fluorinating agent through the flow-through column for a certain period while heating the flow-through column can be mentioned.

[0055] Examples of the fluorinating agent include a fluorine radical source that generates fluorine radicals under fluorination treatment conditions. Examples of the above-mentioned fluorine radical source include F2 gas, N2F2, and halogen fluorides (for example, IF5 and ClF3, etc.). The concentration of the fluorine radical source such as F2 gas may be 100% by volume. From the viewpoint of safety, it is preferable to use a mixed gas obtained by diluting with an inert gas so that the concentration of F2 gas is 5 to 50% by volume (more preferably 15 to 30% by volume). Examples of the inert gas include nitrogen gas, helium gas, and argon gas, and nitrogen gas is preferable from the viewpoint of economy.

[0056] In the flow-through contact of the fluorinating agent, the linear velocity of the fluorinating agent flowing through the reactor is preferably 0.1 to 10.0 cm / sec, more preferably 0.5 to 5.0 cm / sec, in terms of better removal efficiency of unstable end groups. Also, the amount of the fluorinating agent brought into contact with the solid is preferably 0.00025 L / g or more, more preferably 0.0005 L / g or more, per mass of the solid in terms of better stabilization of unstable end groups, and preferably 0.032 L / g or less, more preferably 0.016 L / g or less, in terms of better utilization efficiency of the fluorinating agent.

[0057] In the flow-through contact of the fluorinating agent, the treatment temperature is preferably below the melting point of the copolymer, more preferably 20 to 240 °C, still more preferably 30 to 240 °C, and particularly preferably 100 to 235 °C, in terms of better removal efficiency of unstable end groups. The treatment time of the flow-through contact of the fluorinating agent is appropriately changed depending on the number of functional groups of the copolymer before the fluorination treatment and the number of target functional groups, and is, for example, 0.5 to 30 hours, preferably 1 to 24 hours.

[0058] The solid to which the fluorinating agent is brought into flow-through contact is preferably in particulate or pellet form, more preferably particulate, from the viewpoint of being easily fluorinated while removing by-products and impurities generated by the fluorination treatment, reducing the outgassing amount of the solid, and easily producing the present solid excellent in ozone resistance with the outgassing amount within a predetermined range. The bulk density of the solid to which the fluorinating agent is brought into flow-through contact is preferably 0.1 g / cm 3 or more, and 0.2 g / cm 3The above is more preferable. The bulk density of the solid with which the fluorinating agent is brought into flow contact is preferably 0.8 g / cm 3 or less, more preferably 0.7 g / cm 3 or less, in terms of more excellent removal efficiency of the unstable end group.

[0059] It is preferable to further bring an inert gas into flow contact with the solid with which the above fluorinating agent has been brought into flow contact. By bringing an inert gas into flow contact after the flow contact of the fluorinating agent, the amount of outgas generated from the solid can be further reduced. This is presumably because components such as the fluorinating agent and reaction by-products contained in the solid are removed by the flow contact of the inert gas.

[0060] Examples of the inert gas to be brought into flow contact include nitrogen gas, helium gas, and argon gas, and nitrogen gas is preferable from the viewpoint of economy.

[0061] In the flow contact of the inert gas, the linear velocity of the inert gas fluorinating agent flowing through the reactor is preferably 0.1 to 10.0 cm / second, more preferably 0.5 to 10.0 cm / second, in terms of more excellent removal of the fluorinating agent and reaction by-products. Also, the amount of the inert gas brought into contact with the solid is preferably 0.005 L / g or more, more preferably 0.010 L / g or more, per mass of the solid in terms of more excellent removability of the reaction by-products, and preferably 10 L / g or less, more preferably 5 L / g or less, in terms of more excellent productivity and utilization efficiency of the inert gas, when converted to the standard state. .

[0062] The treatment temperature in the flow contact of the inert gas is preferably equal to or lower than the melting point of the copolymer, more preferably 30 to 240 °C, and still more preferably 100 to 235 °C, in terms of more excellent removal of the fluorinating agent and reaction by-products. The treatment time of the flow contact of the inert gas is, for example, 0.5 to 30 hours, preferably 1 to 24 hours.

[0063] For the solid obtained by the flow contact of a fluorinating agent or the flow contact of an inert gas, known treatments such as the above-mentioned grinding treatment and pelletizing treatment may be performed. Specifically, a pelletizing treatment may be performed on the solid obtained by bringing a particulate solid into flow contact with a fluorinating agent or bringing an inert gas into flow contact therewith to obtain a pellet-shaped solid. Even in such a case, a solid having an outgas generation amount within a predetermined range can be obtained.

[0064] [Second Embodiment: Method for Producing Solid] The method for producing a solid according to the second embodiment of the present invention (hereinafter, also referred to as "this production method") involves bringing a fluorinating agent into flow contact with a powdery or pellet-shaped solid containing a copolymer containing unit A and unit B, reducing the total number of specific functional groups in the copolymer, and being a copolymer containing unit A and unit B, wherein the total number of specific functional groups is less than 150 per 10 main chain carbon atoms of the copolymer 6 It is a method for producing a solid that obtains a powdery or pellet-shaped solid containing a copolymer. By this production method, a powdery or pellet-shaped solid containing a copolymer containing unit A and unit B can be produced, which has a small outgas generation amount when heated to 300°C, is less likely to generate cracks and blisters due to ozone, and can form a molded article with excellent ozone resistance.

[0065] Regarding the powdery or pellet-shaped solid that is the object of bringing the fluorinating agent into flow contact in this production method and the copolymer contained in the solid, except for the content of specific functional groups and the outgas generation amount, including preferred embodiments, it is as described for the solid and the copolymer contained in the solid before the fluorination treatment in the first embodiment. The outgas generation amount when the powdery or pellet-shaped solid that is the object of bringing the fluorinating agent into flow contact in this production method is heated to 300°C is usually more than 100 mass ppb with respect to the total mass of the solid, in terms of n-hexane. In addition, the number of functional groups in the copolymer contained in the powdery or pellet-like solid to which the fluorinating agent is circulated and contacted in this production method is usually 150 or more per 10 carbon atoms in the main chain of the copolymer. 6 per carbon atom.

[0066] Regarding the method of circulating and contacting the fluorinating agent with the solid containing unit A and unit B in this production method, including preferred embodiments, it is as already described as the production method of the solid according to the first embodiment.

[0067] The solid produced by this production method preferably has an outgas generation amount of 100 mass ppb or less, more preferably less than 50 mass ppb, and even more preferably less than 25 mass ppb, in terms of n-hexane, with respect to the total mass of the solid when heated to 300°C. The outgas generation amount may be 0 mass ppb with respect to the total mass of the solid. Regarding other properties of the solid produced by this production method, including preferred embodiments, it is as described for the solid according to the first embodiment.

[0068] [Molded article] The molded article of the present invention is obtained by molding the solid according to the first embodiment of the present invention or the solid produced by the production method according to the second embodiment of the present invention. Specific examples of the molded article of the present invention include an injection molded article obtained by injection molding the solid, an extrusion molded article obtained by extrusion molding, a blow molded article obtained by blow molding, a transfer molded article obtained by transfer molding, a press molded article obtained by press molding, a rotational molded article obtained by rotational molding, and a coating film obtained by electrostatic coating. The molded article of the present invention is preferably a press molded article obtained by press molding. Also, an injection molded article is preferable because an injection molded article with a beautiful appearance can be obtained without corroding the mold used for molding.

[0069] Specific examples of the molded article of the present invention include nuts, bolts, joints, films, bottles, gaskets, wire coatings, tubes, hoses, pipes, valves, sheets, seals, packings, tanks, rollers, containers, cocks, connectors, filter housings, filter cages, flow meters, pumps, wafer carriers, and wafer boxes.

[0070] The solid substance, the solid substance produced by the production method according to the second embodiment, or the molded article of the present invention can be used for the following applications. Food packaging films, lining materials for fluid transfer lines used in food manufacturing processes, packings, sealing materials, and fluid transfer members for food manufacturing equipment such as sheets; medicine plugs for pharmaceuticals, packaging films, lining materials for fluid transfer lines used in pharmaceutical manufacturing processes, packings, sealing materials, and chemical liquid transfer members such as sheets; inner surface lining members for chemical liquid tanks and pipes in chemical plants or semiconductor factories; O-ring (angle) rings, tubes, packings, valve core materials, hoses, and sealing materials used in the fuel systems and peripheral devices of automobiles, and fuel transfer members such as hoses and sealing materials used in the AT devices of automobiles; flange gaskets for carburetors, shaft seals, valve stem seals, sealing materials, and hoses used in automobile engines and peripheral devices, and other automobile members such as automobile brake hoses, air conditioner hoses, radiator hoses, and wire coatings; O-ring (angle) rings, tubes, packings, valve core materials, hoses, sealing materials, rolls, gaskets, diaphragms, and joints for chemical liquid transfer members for semiconductor devices in semiconductor manufacturing equipment; coating rolls, hoses, tubes, and ink containers for coating equipment, and coating and ink members such as tubes, hoses, belts, packings, and joints for food and beverages, food packaging materials, and glass cooking utensils; waste liquid transfer members such as tubes and hoses for waste liquid transportation; high-temperature liquid transfer members such as tubes and hoses for high-temperature liquid transportation; steam piping members such as tubes and hoses for steam piping; anticorrosive tapes for piping such as tapes wound around pipes on the decks of ships; various coating materials such as wire coatings, optical fiber coatings, transparent surface coatings and back coatings provided on the light incident side surface of the photoactive elements of solar cells; sliding members such as diaphragms of diaphragm pumps and various packings; agricultural films, carrier films for fuel cells, and weather-resistant covers such as various roofing materials and side walls; interior materials used in the construction field, and coating materials for glasses such as non-combustible fire safety glasses; lining materials such as laminated steel sheets used in the household appliance field, etc.

[0071] Among others, the molded article of the present invention can be suitably used as a piping member (for example, a pipe, a joint, a gasket, and a packing) or a tube for transferring a fluid in a semiconductor manufacturing apparatus. In addition, the molded article of the present invention can also be suitably used as an electric wire coating material. As a specific usage mode, a coated electric wire including a core wire and a coating layer provided around the core wire and made of the molded article of the present invention can be mentioned. The coated electric wire including the coating layer made of the molded article of the present invention has excellent electrical characteristics because the core wire is hardly corroded and there is almost no variation in the outer diameter, and is suitably used as a high-frequency transmission cable, a flat cable, a heat-resistant cable, etc. Such a coated electric wire can be manufactured, for example, by melt-extrusion molding a copolymer or the present composition on the core wire to form a coating layer.

[0072] In addition, the molded article of the present invention can also be suitably used as a member to be compressed. A member to be compressed is a member used in a state of being compression-deformed, and the size and shape of the member to be compressed are appropriately set according to the application. The shape of the member to be compressed may be, for example, annular. Further, the member to be compressed may have a shape such as a circle, an ellipse, or a square with rounded corners in a plan view, and may have a through hole in the central portion thereof. The member to be compressed can be used as a piping member for transferring a fluid. Further, the member to be compressed can be used as a member for constituting a non-aqueous electrolyte battery, and is particularly suitable as a member used in a state of being in contact with the non-aqueous electrolyte in the non-aqueous electrolyte battery. The member to be compressed can also be suitably used as a sealing member such as a sealing gasket and a sealing packing, and an insulating member such as an insulating gasket and an insulating packing. A sealing member is a member used to prevent leakage of a liquid or a gas, or intrusion of a liquid or a gas from the outside. An insulating member is a member used to insulate electricity. The member to be compressed may be a member used for both purposes of sealing and insulation.

Examples

[0073] Hereinafter, the present invention will be described in detail with examples. Examples 1 and 3 to 5 are examples, and Example 2 is a comparative example. However, the present invention is not limited to these examples. The various measurement methods and evaluation methods are as follows.

[0074] [Measurement] [Composition of copolymer] The contents (mol%) of unit A and unit B in each copolymer were determined by 19 converting the molar ratio calculated by 19F-NMR analysis.

[0075] [Number of functional groups N] Using the solid obtained in each example as a raw material, it was molded by a hot press at 330 °C to produce a film with a thickness of 0.30 to 0.35 mm. This film was scanned 40 times with a Fourier transform infrared spectrometer (FT-IR, "Spectrum One" manufactured by PerkinElmer) and analyzed to obtain an infrared absorption spectrum. Next, the solid obtained in each example was subjected to the fluorination treatment described below for a long time to separately prepare each base pellet that was completely fluorinated and had no specific functional groups. In the same manner as above, a base film was obtained. Next, a difference spectrum was obtained between the infrared absorption spectrum of the film obtained by molding the solid of each example and the base spectrum of the base film. From the absorption peak of the specific functional group appearing in this difference spectrum, according to the above formula (A), the number of specific functional groups per 10 main chain carbons of the copolymer contained in each solid 6 was calculated as the total number of specific functional groups (number of functional groups N).

[0076] [Outgas generation amount] The outgas generation amount when the solid obtained in each example was heated at 300 °C for 120 minutes was measured using a headspace GC-MS (HS-GC-MS) device. As follows, from the total amount of gaseous substances detected by HS-GC-MS analysis, after removing the components derived from the column, the amount obtained by further converting to the amount of n-hexane was defined as the outgas generation amount.

[0077] More specifically, n-hexane was diluted with toluene to prepare n-hexane standard solutions with n-hexane concentrations of 10 mass ppb, 100 mass ppb, 500 mass ppb, 1000 mass ppb, and 5000 mass ppb, respectively. 2 μL of each standard solution was weighed with a microsyringe, and after putting the entire amount into a headspace vial and sealing it, each standard solution was measured under the measurement conditions described below using the HS-GC-MS apparatus described below. From the concentration of the standard solution and the integrated value of the measured peak area, a straight line passing through the origin (0 point) and represented by the following formula (A1) was derived by linear approximation, and the slope a was determined. A = a×X (A1) In formula (A1), A represents the peak area of the detected n-hexane, and X represents the concentration of n-hexane in the measurement sample (unit: mass ppb).

[0078] Next, 1 g of the solid obtained in each example was put into a headspace vial and sealed, and analyzed under the same conditions as the above n-hexane standard solution. After calculating all the peak areas obtained excluding the components derived from the column, the calculated peak areas were summed. From the sum of the obtained peak areas, the outgas generation amount when the solid was heated to 300 °C was calculated using the following formula (A2). XCm = ACm / a (A2) In formula (A2), XCm represents the outgas generation amount (unit: mass ppb) when the solid is heated at 300 °C for 120 minutes, ACm represents the sum of the peak areas of the components detected by HS-GC-MS analysis, and a represents the slope a of the calibration curve represented by formula (A1).

[0079] (HS-GC-MS apparatus) GC section: "7890B" manufactured by Agilent MS section: "5977B" manufactured by Agilent HS section: "7697A" manufactured by Agilent (HS-GC-MS measurement conditions) ·HS Heating temperature: 300 °C Heating time: 120 minutes Pressurization time: 1 minute GC cycle time: 50 minutes Transfer line temperature: 255 °C ·GC Column: DB-1301 (length 60 m, inner diameter 0.25 mm, film thickness 1 μm) Heater (injection line temperature): 255 °C Split ratio: 30 Column flow rate: Total flow: 1 mL / min (helium gas) Oven temperature: Held at 40 °C for 5 minutes, then heated at 10 °C / min until reaching 280 °C and held for 10 minutes (total 39 minutes) ·MS Interface temperature: 150 °C Ion source temperature: 230 °C Ionization method: EI Detection: Scan method Target ion: m / z = 35 - 700

[0080] <mfr> For each solid obtained, using a melt indexer (manufactured by Technoseven Co., Ltd.), in accordance with ASTM D1238, under the conditions of a temperature of 372 °C and a load of 5 kg, the mass (g) of the solid flowing out from an orifice with a diameter of 2 mm and a length of 8 mm in 10 minutes was measured and taken as the MFR (g / 10 min).

[0081] [Evaluation Test] [Ozone Resistance] The solids produced in each example were compression molded at 340 °C to produce a sheet with a thickness of 1 mm. A 10 mm × 20 mm size was cut out from the obtained sheet and used as a sample for the ozone exposure test.

[0082] A test apparatus was prepared in which an ozone generator (product name: SGX - A11MN (modified), manufactured by Sumitomo Seiki Kogyo Co., Ltd.), a PFA container filled with ion - exchanged water, and a PFA cell containing the sample were connected in this order. Ozone gas (ozone / oxygen volume ratio = 10 / 90) generated by the ozone generator was bubbled in ion - exchanged water to add water vapor to the ozone gas. The obtained wet ozone gas was circulated through the PFA cell containing the sample at 0.7 liter / min to expose the sample to the wet ozone gas. In the ozone exposure test, the temperature was maintained at 40 °C and the humidity was maintained at 80% RH.

[0083] 180 days after the start of the ozone exposure test, the sample was taken out and the surface of the sample was gently rinsed with ion - exchanged water. Then, the surface of the sample was photographed using a laser microscope, and the number of cracks with a length of 1 μm or more per 1 mm 2 of the sample surface and the number of blisters with a major axis of 1 μm or more were measured. The major axis of the blister means the maximum diameter of the blister as seen from the normal direction of the sample surface. Based on the following evaluation criteria, the ozone resistance of each solid was evaluated from the measured number of the above - mentioned cracks and the number of the above - mentioned blisters.

[0084] [Ozone Resistance Evaluation Criteria] ◎: The number of cracks is 10 pieces / mm 2 or less and the number of blisters is 10 pieces / mm 2 or less 〇: Number of cracks is 10 per mm 2 or less and number of blisters is 10 per mm 2 exceeding △: Number of cracks is 10 per mm 2 exceeding and number of blisters is 10 per mm 2 or less ×: Number of cracks is 10 per mm 2 exceeding and number of blisters is 10 per mm 2 exceeding

[0085] <Surface smoothness> The solid obtained in each example was press-molded at 340 °C to obtain a film with a thickness of 1 mm. The press molding was carried out using a hot press machine ("SA-301" manufactured by Tester Sangyo Co., Ltd.). The smoothness of the surface of the obtained film was confirmed by the tactile sensation when a finger was brought into contact with the surface of the film, and evaluated according to the following criteria.

[0086] (Surface smoothness evaluation criteria) 〇: The surface is smooth. △: The surface is slightly rough. ×: The surface is rough.

[0087] [Example 1] The polymerization tank with a stirrer having an internal volume of 96.3 L was degassed, and then 27.2 kg of CF3CH2OCF2CF2H (AE-3000: product name, manufactured by AGC), 43.0 kg of water, 2.69 kg of CF2=CFO(CF2)3F (PPVE), and 3.484 kg of methanol were charged into the polymerization tank. Next, the temperature inside the polymerization tank was raised to 50 °C (polymerization temperature), and 9.20 kg of tetrafluoroethylene (TFE) was further charged, and the pressure inside the polymerization tank was increased to 1.31 MPa (gauge pressure). 80 mL of a 0.2 mass% AE-3000 solution of heptafluorobutyryl peroxide was charged as a polymerization initiator solution to initiate polymerization, and then the above polymerization initiator solution was continuously added. Also, TFE was continuously charged so that the pressure during polymerization was maintained at the same level as the pressure at the start of polymerization. 292 minutes elapsed from the start of polymerization. When 650 mL of the polymerization initiator solution and 13.0 kg of TFE were charged, the temperature inside the polymerization tank was lowered to 15 °C, and the inside of the polymerization tank was purged until the pressure reached 1 atm.

[0088] The slurry of the obtained copolymer was filtered through a filter to separate the polymerization medium, and then dried at 150 °C for 15 hours to obtain copolymer X1. 19 As a result of 19F-NMR analysis, the composition of copolymer X1 was unit A / PPVE unit = 98.55 / 1.45 (mol%). The "PPVE unit" is a unit based on CF2=CFO(CF2)3F in each copolymer and is included in unit B. Also, in the analysis of the above copolymer X1, no units other than the PPVE unit included in unit B were detected. Also, the number of functional groups N of copolymer X1 determined according to the above measurement method was 500 or more per 10 main chain carbon atoms. 6

[0089] A co-rotating twin-screw extruder equipped with a screw having two kneading sections was prepared. Copolymer X1 was charged into the hopper of the feeder of the twin-screw extruder, and under the conditions of a cylinder temperature of 380 °C and a screw rotation speed of 100 rpm, while sucking the vent section with a vacuum pump, Copolymer X1 was kneaded. The strand discharged from the vent section was gradually cooled and cut with a pelletizer to produce a pellet-shaped solid X1 containing Copolymer X1. The shape of the solid X1 was cylindrical with a length of 5 mm or less and a ratio of length to diameter (length / diameter) of 0.5 or more and less than 1.5.

[0090] Next, the solid X1 was fluorinated by the following method. A reactor having a cylindrical shape with an inner diameter of 21 mm and pipes connected to both ends in the length direction was prepared so that gas could flow through the inside of the reactor from one end to the other end. The reactor was filled with the solid X1, thoroughly purged with N2 gas, and then the reactor was heated to raise the temperature to 230 °C. F2 gas diluted to 20% by volume with N2 gas was passed through the reactor at a linear velocity of 10 mm / second for 4 hours and brought into contact with the solid X1. During the flow-through contact, the pressure inside the reactor was 1 atm, and the temperature of the reactor was maintained at 230 °C.

[0091] Next, while maintaining the pressure inside the reactor at 1 atm and the reactor at 230 °C, N2 gas was passed through the reactor and brought into contact with the solid X1 to obtain a pellet-shaped solid Y1 containing Copolymer Y1. The total amount of N2 gas passed through the reactor was 1 L (converted to standard conditions) per 1 g of the solid X1. Also, the linear velocity of the N2 gas passed through the reactor was 20 mm / second.

[0092] 19 As a result of 19F-NMR analysis, the composition of Copolymer Y1 contained in the solid Y1 was the same as that of Copolymer X1, i.e., unit A / PPVE unit = 98.55 / 1.45 (mol%), and no unit B other than the PPVE unit was detected. Also, the number of functional groups N of Copolymer Y1 was 10 or less per 10 main-chain carbon atoms 6 pieces.

[0093] [Example 2] The pellet-shaped solid X1 obtained in Example 1 was placed in a vacuum vibration reactor (manufactured by Okawara Seisakusho), and the temperature was raised to 210°C. After evacuation, F2 gas diluted to 20% by volume with N2 gas was introduced up to 1 atm. Half an hour after the start of the introduction of the diluted F2 gas, the reactor was evacuated once, and then the diluted F2 gas was introduced again. After another half an hour, the reactor was evacuated again, and the diluted F2 gas was introduced again. Thereafter, the above operations of introducing the diluted F2 gas and evacuation were continued once per hour, and the solid X1 and the diluted F2 gas were reacted at a temperature of 210°C for 10 hours. After the reaction was completed, the inside of the reactor was sufficiently replaced with N2 gas to complete the fluorination treatment. By the fluorination treatment, a pellet-shaped solid Y2 containing the copolymer Y2 was obtained. The number of functional groups N of the copolymer Y2 contained in the solid Y2 was more than 150 per 10 6 main chain carbon atoms.

[0094] [Example 3] A polymerization tank with a stirrer having an internal volume of 96.3 L was degassed, and then 27.2 kg of AE-3000, 43.0 kg of water, 2.69 kg of PPVE, and 3.484 kg of methanol were charged into the polymerization tank. Next, the temperature inside the polymerization tank was raised to 50°C (polymerization temperature), 9.20 kg of TFE was further charged, and the pressure inside the polymerization tank was increased to 1.31 MPa (gauge pressure). 80 mL of a 0.2 mass% AE-3000 solution of heptafluorobutyroyl peroxide was charged as a polymerization initiator solution to start the polymerization, and then the above polymerization initiator solution was continuously added. Also, TFE was continuously charged so that the pressure during polymerization was maintained at the same level as the pressure at the start of polymerization. 292 minutes after the start of polymerization, when 650 mL of the polymerization initiator solution and 13.0 kg of TFE were charged, the temperature inside the polymerization tank was lowered to 15°C, and the pressure inside the polymerization tank was purged until it reached 1 atm.

[0095] The obtained slurry of the copolymer was heated to 90°C while stirring to remove the polymerization medium, then filtered to separate water, and heated and dried at 150°C for 15 hours to obtain a powdery solid X3 containing the copolymer X3. 19 As a result of the 19F-NMR analysis, the composition of copolymer X3 was unit A / PPVE unit = 98.55 / 1.45 (mol%). Also, in the analysis of copolymer X3, units other than the PPVE unit and contained in unit B were not detected. Also, the number of functional groups N of copolymer X3 determined according to the above measurement method was 500 or more per 10 main chain carbon atoms 6 atoms. Furthermore, as a result of measurement according to the above measurement method, the bulk density of solid X3 was 0.5 g / cm 3 and the average particle diameter of solid X3 was 250 μm.

[0096] A fluorination treatment of solid X3 was carried out in the same manner as in Example 1, except that solid X3 was used instead of solid X1, to obtain a powdery solid Y3 containing copolymer Y3. 19 The composition of copolymer Y3 measured by 19F-NMR analysis and the number of functional groups N of copolymer Y3 are shown in Table 2 below. Also, in the analysis of copolymer Y3 above, units other than the PPVE unit and contained in unit B were not detected. Also, the bulk density and average particle diameter of solid Y3 were the same as those of solid X3, respectively.

[0097] [Example 4] In the step of flowing N2 gas into the reactor after fluorination treatment of pellet-shaped solid X1, a pellet-shaped solid Y4 containing copolymer Y4 was obtained in the same manner as in Example 1, except that the temperature of the reactor was lowered to 20 °C and then N2 gas was flowed and brought into contact with solid X1. 19 The composition of copolymer Y4 measured by 19F-NMR analysis and the number of functional groups N of copolymer Y4 are shown in Table 2 below. Also, in the analysis of copolymer Y4 above, units other than the PPVE unit and contained in unit B were not detected.

[0098] [Example 5] The polymerization tank with a stirrer having an internal volume of 96.3 L was degassed, and then 27.2 kg of AE-3000, 43.0 kg of water, 9.5 kg of PPVE, and 0.89 kg of methanol were charged into the polymerization tank. Next, the temperature inside the polymerization tank was raised to 50 °C (polymerization temperature), and 9.20 kg of TFE was further charged, and the pressure inside the polymerization tank was increased to 1.31 MPa (gauge pressure). 270 mL of a 0.2 mass% AE-3000 solution of heptafluorobutyryl peroxide was charged as a polymerization initiator solution to initiate polymerization, and thereafter the above polymerization initiator solution was continuously added. Also, TFE was continuously charged so that the pressure during polymerization was maintained at the same level as the pressure at the start of polymerization. 492 minutes elapsed from the start of polymerization. When 1260 mL of the polymerization initiator solution and 11.0 kg of TFE were charged, the temperature inside the polymerization tank was lowered to 15 °C, and the inside of the polymerization tank was purged until the pressure reached 1 atm.

[0099] The slurry of the obtained copolymer was filtered through a filter to separate the polymerization medium, and then dried at 150 °C for 15 hours to obtain copolymer X5. 19 As a result of 19F-NMR analysis, the composition of copolymer X5 was unit A / PPVE unit = 94.50 / 5.50 (mol%). Also, in the analysis of the above copolymer X5, units other than the PPVE unit contained in unit B were not detected. Also, the number of functional groups N of copolymer X5 determined according to the above measurement method was 1500 or more per 10 main chain carbon atoms 6 atoms.

[0100] A fluorination treatment of solid X5 was performed in the same manner as in Example 1 except that solid X5 was used instead of solid X1, and a pellet-shaped solid Y5 containing copolymer Y5 was obtained. 19 The composition of copolymer Y5 measured by 19F-NMR analysis and the number of functional groups N of copolymer Y5 are shown in Table 2 below. Also, in the analysis of the above copolymer Y5, units other than the PPVE unit contained in unit B were not detected.

[0101] The composition of the copolymer and the evaluation results for each example are shown in the following table. The column of "Number of functional groups N" indicates the total number of specific functional groups in copolymer X contained in solid X or copolymer Y contained in solid Y. For example, the notation of "500<" in the column of "Number of functional groups N" of "Copolymer X" in Example 1 means that the total number of specific functional groups per 10 main chain carbon atoms of copolymer X (copolymer X1) was more than 500. The notation of "≦10" in the column of "Number of functional groups N" of "Copolymer Y" in Example 1 means that the total number of specific functional groups per 10 main chain carbon atoms of copolymer Y (copolymer Y1) was 10 or less. 6 This means that the total number of specific functional groups per 10 main chain carbon atoms of copolymer Y (copolymer Y1) was 10 or less. 6 In the table, the column of "Unit A (mol%)" indicates the content of unit A (unit: mol%) relative to all units contained in the copolymer. The column of "Unit B (mol%)" indicates the content of unit B (unit: mol%) relative to all units contained in the copolymer. The notation of "25~50" in the columns of Example 1 and Example 5 in the "Outgassing amount (mass ppb)" means that the outgassing amount converted to the amount of n-hexane measured by the above measurement method was 25~50 mass ppb relative to the total mass of the solids in Example 1 and Example 5. The notation of "<25" in Example 3 means that the outgassing amount converted to the amount of n-hexane measured by the above measurement method was less than 25 mass ppb relative to the total mass of the solid in Example 3. Note that in each example, the contents of unit A and unit B of copolymer X contained in solid X before fluorination treatment and the contents of unit A and unit B of copolymer Y contained in solid Y after fluorination treatment were the same, respectively.

[0102] In addition, as a result of analyzing the solid of each example by F-NMR, the content of the copolymer containing unit A and the unit based on hexafluoropropylene was less than 0.1 mass% relative to the total mass of the solid in each case. 19

[0103]

Table 2

[0104] ​As shown in the above table, the number of functional groups N is less than 150 per 10 main chain carbons of the copolymer, and when heated to 300 °C, the outgas generation amount is 100 mass ppb or less in terms of n-hexane with respect to the total mass of the solid matter. By using the solid matter of the present invention, it was confirmed that cracks and blisters due to ozone are less likely to occur, and a molded body excellent in ozone resistance can be formed (Examples 1 and 3 to 5). 6 ​< / mfr>

Claims

1. A powder or pellet-like solid material comprising a copolymer containing units A based on tetrafluoroethylene and units B based on a monomer represented by formula (1), -CF = CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of OH functional groups is 10 or less than 10 carbon atoms in the main chain of the copolymer. ６ There are less than 150 pieces per piece, The solid material is characterized in that an amount of outgassing, calculated as n-hexane, when the solid material is heated at 300° C. for 120 minutes is 100 ppb by mass or less based on the total mass of the solid material. Formula (1) CF ２ = CF - O - Rf Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms, and the perfluoroalkyl group may have an etheric oxygen atom between carbon atoms.

2. The solid material according to claim 1, wherein the content of the unit A is 97.00 to 99.50 mol % based on the total units of the copolymer.

3. 2. The solid material according to claim 1, wherein the content of the unit B is 0.50 to 3.00 mol % based on the total units of the copolymer.

4. 2. The solid material according to claim 1, wherein the melt flow rate of the copolymer, measured according to ASTM D1238 under conditions of a temperature of 372° C. and a load of 5 kg, is 1.0 to 50.0 g / 10 min.

5. 2. The solid material of claim 1, wherein the unit B comprises a unit based on perfluoro(propyl vinyl ether).

6. A molded product obtained by molding the solid material according to any one of claims 1 to 5.

7. A fluorinating agent is contacted with a powder or pellet-shaped solid material containing a copolymer containing units A based on tetrafluoroethylene and units B based on a monomer represented by formula (1) at a linear velocity of 0.1 to 10.0 cm / sec, and -CF=CF in the copolymer is formed. ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ A copolymer including the unit A and the unit B, wherein the total number of functional groups is reduced so that the total number of functional groups is 10 or less than the main chain carbon number of the copolymer. ６ A method for producing a solid material, comprising obtaining a powdered or pelletized solid material containing a copolymer having less than 150 units per pellet. Formula (1) CF ２ = CF - O - Rf Rf represents a perfluoroalkyl group having 1 to 10 carbon atoms, and the perfluoroalkyl group may have an etheric oxygen atom between carbon atoms.

8. contacting an inert gas with the solid material with which the fluorinating agent has been contacted; The method for producing a solid material according to claim 7, wherein the amount of the inert gas to be contacted through the solid material is 0.005 L / g or more in terms of a volume converted to a standard state per mass of the solid material.

9. The method for producing a solid material according to claim 8, wherein the treatment temperature in the flow contact of the inert gas is 30 to 240° C.

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