Solid, molded body, and method for producing solid

Abstract

The present invention addresses the problem of providing a solid that can be formed into a molded body which has excellent ozone resistance and is unlikely to develop cracks and blisters due to ozone and providing a molded body and a method for producing a solid.　A solid according to the present invention is a powdery or pellet-like solid which contains a copolymer that contains a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by formula (1) (CF2=CF-O-Rf). The total number of functional groups represented by -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH is less than 150 per 106 main-chain carbon atoms in the copolymer, and the amount of outgas generated when the solid is heated at 300°C for 120 minutes is 100 mass ppb or less relative to the total mass of the solid, in terms of n-hexane.

Description

Solid matter, molded body, method for manufacturing solid matter

[0001] This invention relates to solid matter, molded articles, and methods for producing solid matter.

[0002] A copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PFA") is known as a fluororesin that has excellent mechanical, chemical, and electrical properties and can be melt-processed. For example, Patent Document 1 discloses a molding material for ozone-resistant articles made of a copolymer of tetrafluoroethylene and perfluorovinyl ether.

[0003] International Publication No. 2003 / 048214

[0004] Recently, when PFA molded bodies are used as piping materials for semiconductor manufacturing equipment, there is a growing demand for even greater ozone resistance in these molded bodies. When the present inventors evaluated a molded body formed using PFA as described in Patent Document 1, they found that its ozone resistance did not meet the higher level of requirements demanded today, and that further improvements were necessary.

[0005] This invention has been made in view of the above problems and aims to provide a solid material that can form a molded article with excellent ozone resistance, which is less prone to cracking and blistering due to ozone. Furthermore, this invention also aims to provide a method for manufacturing the molded article and the solid material.

[0006] As a result of diligent study on the above problem, the present inventors have provided a powdered or pelletized solid 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 copolymer has -CF=CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of OH functional groups in the copolymer is equal to the number of carbon atoms in the copolymer. ６Using solids that are less than 150 per piece and have an outgassing amount of 100 mass ppb or less in terms of n - hexane with respect to the total mass of the solid when the solid is heated to 300 °C, it has been found that a molded article with excellent ozone resistance can be formed, and the present invention has been achieved.

[0007] That is, the inventors have found that the above problems can be solved by the following configuration. [1] A powdery or pellet - like solid containing a copolymer containing a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by the following formula (1), having -CF = CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of functional groups of OH is less than 150 per 10 ６ main - chain carbon atoms of the above copolymer, and the outgassing amount when the above solid is heated at 300 °C for 120 minutes is 100 mass ppb or less in terms of n - hexane with respect to the total mass of the above solid. A solid characterized by the above. [2] The solid according to [1], wherein the content of the above unit A is 97.00 to 99.50 mol% with respect to all units of the above copolymer. [3] The solid according to [1], wherein the content of the above unit B is 0.50 to 3.00 mol% with respect to all units of the above copolymer. [4] The solid according to [1], wherein the melt flow rate of the above 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 above unit B contains a unit based on perfluoro(propyl vinyl ether). [6] A molded article characterized by being obtained by molding the solid according to any one of [1] to [5]. [7] A fluorinating agent is circulated and contacted with a powdery or pellet - like solid containing a copolymer containing a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by the following formula (1), and -CF = CF in the above copolymer ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH２ and -CH ２ A copolymer comprising the above unit A and the above unit B, wherein the total number of OH functional groups is reduced and the number of carbon atoms in the main chain of the copolymer is 10 ６ A method for producing a solid, characterized by obtaining a powdered or pelletized solid containing a copolymer having fewer than 150 units per unit. [8] A method for producing a solid according to [7], wherein an inert gas is brought into flow contact with the solid that has been brought into flow contact with the fluorinating agent, and the amount of the inert gas brought into flow contact is 0.005 L / g or more in volume converted to standard conditions per mass of the solid. [9] A method for producing a solid according to [8], wherein the processing temperature in the flow contact of the inert gas is 30 to 240°C.

[10] A method for producing a solid according to [7] to [9], wherein the fluorinating agent is brought into flow contact with the solid at a linear velocity of 0.1 to 10.0 cm / second.

[0008] According to the present invention, it is possible to provide a solid material that can form a molded article with excellent ozone resistance, such as one that is less prone to cracking and blistering due to ozone. Furthermore, according to the present invention, it is possible to provide a method for manufacturing both the molded article and the solid material.

[0009] In this specification, the meanings of terms are as follows: A numerical range indicated by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0010] A "unit" is a general term for an atomic group derived from one monomer molecule directly formed by the polymerization of monomers, and an atomic group obtained by chemically transforming a part of the above atomic group. In the following, as appropriate, units derived from individual monomers will be referred to by adding "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) 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.

[0011] "Specific functional group" refers to -CF=CF２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ This refers to the functional groups included in the group consisting of OH groups. Furthermore, "number of functional groups" refers to the total number of specific functional groups present in the copolymer, unless otherwise specified.

[0012] "Solid matter" refers to a composition that is solid at 25°C. "Powdered solid matter" refers to a composition with an average particle size of 3000 μm or less and a bulk density of 0.1 to 0.8 g / cm³. ３ It refers to an object that is a pelletized solid. "Pelletized solid" refers to a granular molded product manufactured by extruding and cutting a solid material.

[0013] [First Embodiment: Solid] The solid according to the first embodiment of the present invention (hereinafter also referred to as "the solid") includes a copolymer (hereinafter also referred to as "the copolymer") which contains unit A and unit B and has a specific functional group within a predetermined content range. When the solid is heated at 300°C for 120 minutes, the amount of outgassing is 100 ppb by mass or less relative to the total mass of the solid, when converted to n-hexane.

[0014] By using this solid material, it is possible to form molded articles with excellent ozone resistance, which are less prone to cracking and blistering due to ozone. The details of this reason are not yet clear, but it is presumed to be due to the following reasons. The amount of outgassing mentioned above is the amount of gaseous substance derived from the solid material that is generated when the solid material is heated at 300°C for 120 minutes. Here, components from which the gaseous substance originates include, for example, the terminal groups of copolymers contained in the solid material, by-products of fluorination treatment, and impurities. It is presumed that these components are thermally decomposed and become gaseous substances when heated at 300°C for 120 minutes. On the other hand, since ozone promotes the decomposition of organic substances due to its strong oxidizing power, it is presumed that the above components are easily oxidized and decomposed by ozone even under low temperature conditions, generating oxides such as carbon dioxide, which can cause cracks and foaming (blistering) on ​​the surface of the molded article. In contrast, it is presumed that a molded article formed using this solid, which generates less than a predetermined amount of outgassing when heated at 300°C for 120 minutes, can suppress oxidative decomposition upon contact with ozone, thereby suppressing the generation of cracks and blisters caused by ozone and improving ozone resistance. Furthermore, the total number of specific functional groups in the copolymer is less than the number of carbon atoms in the main chain of the copolymer. ６ It is presumed that the presence of fewer than 150 ozone molecules per unit suppresses the oxidative decomposition of specific functional groups by ozone. Thus, it is presumed that by satisfying each requirement, a molded product with excellent ozone resistance was obtained.

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

[0016] <This copolymer> This 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%, and even more preferably 98.00 to 99.50 mol%, relative to the total units contained in the copolymer, in terms of superior heat resistance.

[0018] Unit B is a unit based on the monomer represented by the following formula (1): CF ２ =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 in the perfluoroalkyl group represented by Rf is preferably 1 to 8, more preferably 1 to 6, even more preferably 1 to 5, and particularly preferably 1 to 3, from the viewpoint of superior 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. It is preferable that the perfluoroalkyl group does not have an etheric oxygen atom.

[0019] Specific examples of monomers 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%, even more preferably 1.00 to 3.00 mol%, and particularly preferably 1.50 to 3.00 mol%, relative to the total units contained in the copolymer, in terms of superior moldability, flexibility, and surface smoothness. The copolymer may contain two or more types of unit B. If the 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%, and even more preferably 99.50 to 100.00 mol%, relative to the total units contained in the copolymer, in order to prevent the resulting molded article from being easily deformed by compression or tension.

[0022] In addition to units A and B, this copolymer may also contain units based on TFE and other monomers copolymerizable with the monomer represented by formula (1). Examples of other monomers include ethylene, vinylidene fluoride (VdF), hexafluoropropylene (HFP), and CX. １ X ２ = CX ３ (CF ２ ) ｎ X ４ (In the formula, X １ , X ２ and X ３ Each of these independently represents either a hydrogen atom or a fluorine atom, and X ４ ) represents a monomer, and CF ２ = CF - OCH ２ -Rf ２ (wherein, Rf ２ ) represents a perfluoroalkyl group having 1 to 5 carbon atoms. Examples include monomers represented by ). When the copolymer contains units based on other monomers, the content of units based on other monomers is preferably less than 2.50 mol%, more preferably less than 1.00 mol%, and even more preferably less than 0.50 mol%, relative to the total number of units contained in the copolymer.

[0023] This copolymer preferably contains only units A and B, and does not contain units based on the other monomers mentioned above, in order to have superior abrasion resistance during repeated use. In this case, the total content of units A and B is 100.00 mol% of the total units contained in this copolymer.

[0024] The respective content of unit A, unit B, and other monomer-based units in this copolymer is: １９ It can be measured by known methods such as F-NMR (nuclear magnetic resonance analysis).

[0025] (Number of functional groups) This copolymer has -CF=CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of specific functional groups in the group consisting of OH is equal to the carbon number of the copolymer (10 carbon atoms). ６ The number of functional groups per unit is less than 150. From the viewpoint of forming a molded article with superior ozone resistance, the number of functional groups is preferably 50 or less, more preferably 20 or less, and even more preferably 10 or less. The number of functional groups may be 0.

[0026] Specific functional groups are functional groups present at the ends of the main chain or side chains of the copolymer, and functional groups present in the main chain or side chains. The number of functional groups is the sum of the number of specific functional groups. Specific functional groups are introduced into the copolymer, for example, by a chain transfer agent or polymerization initiator used in the production of the copolymer. More specifically, this may occur when an alcohol is used as a chain transfer agent, or when -CH is used as a polymerization initiator. ２ When using a peroxide having an OH structure, -CH is added to the main chain end of the copolymer. ２ OH is introduced. Furthermore, by polymerizing monomers having functional groups, the functional groups are introduced to the side chain ends of the copolymer. Also, if the number of functional groups in a copolymer having specific functional groups exceeds a predetermined range, the copolymer is fluorinated to remove the specific functional groups -CF ３ The number of functional groups can be reduced by converting them to terminal groups. The number of functional groups in the copolymer can be adjusted by changing the conditions of the fluorination treatment described later (e.g., treatment time, etc.).

[0027] Infrared spectroscopy can be used to identify the types of functional groups and measure the number of functional groups in copolymers. Specifically, the number of functional groups is measured by the following method. First, the copolymer is molded by hot pressing 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) is obtained from a copolymer that is completely fluorinated and does not contain specific functional groups, and the difference spectrum between the infrared absorption spectrum and the base spectrum of the copolymer is obtained. From the absorption peak of the specific functional group appearing in this difference spectrum, the number of carbon atoms in the copolymer is determined according to the following formula (A). ６ Calculate the number of functional groups N per individual.

[0028] N = I × K / t (A) I: Absorbance K: Correction factor t: Film thickness (mm)

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

[0030]

[0031] Furthermore, in copolymers, -CH ２ CF ２ H, -CH ２ COF, -CH ２ COOH, -CH ２ COOCH ３ and -CH ２ CONH ２ The absorption frequency is -CF shown in the table. ２ H, -COF, -COOH (free and bonded), -COOCH ３ , and also, -CONH ２ From each absorption frequency, several tens of kaiser (cm －１ ) becomes lower. For example, the number of -COF is -CF ２ The absorption frequency due to COF is 1883 cm⁻¹. －１ The number of functional groups determined from the absorption peak, and -CH ２The absorption frequency due to COF is 1840 cm⁻¹. －１ This is the sum of the number of functional groups determined from the absorption peaks.

[0032] (Melt Flow Rate) The MFR of this copolymer is preferably 1.0 to 50.0 g / 10 min, and more preferably 3.0 to 45.0 g / 10 min, and more preferably 5.0 to 40.0 g / 10 min, from the viewpoint that a molded article with a good balance of folding resistance and flexural strength can be formed. A specific example of a method for adjusting the MFR of this copolymer to the above range is to adjust the molecular weight of the copolymer. The larger the molecular weight of this copolymer, the smaller the MFR. The MFR of the copolymer is measured in accordance with ASTM D1238, under conditions of a temperature of 372°C and a load of 5 kg, and represents the mass (g) of the copolymer that flows out of an orifice with a diameter of 2 mm and a length of 8 mm in 10 minutes. Note that the copolymer is the main component of the solid, and components other than the copolymer have almost no effect on the measurement of the MFR, so the measured value of the MFR obtained by measuring the solid can be considered 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 of excellent low-speed tear strength of the molded article. A specific example of a method to bring the melting point of this copolymer within the above range is to lower the polymerization temperature during the production of this copolymer. The melting point of this copolymer is the temperature corresponding to the endothermic peak when the copolymer is heated in an air atmosphere at a rate of 10°C / min using a scanning differential thermal analyzer.

[0034] This solid may contain other components besides those listed above. Specific examples of such other components include other resins besides this copolymer, heat stabilizers, antioxidants, colorants, ultraviolet absorbers, fillers, crosslinking agents, crosslinking aids, and organic peroxides. When this 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, per 100 parts by mass of this copolymer.

[0035] This solid material may be in powder or pellet form. The powdered solid material has an average particle size of 3000 μm or less and a bulk density of 0.1 to 0.8 g / cm³. ３ These are particles. In this specification, 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 meter (e.g., manufactured by Kuramochi Scientific Instruments Co., Ltd.) is placed on an electronic balance (e.g., A&D's "EK-1200A"), the sample to be measured is placed in the bulk density meter using a funnel, and then the sample that overflows from the opening surface is removed by leveling it flat along the opening surface of the bulk density meter. After that, the weight of the sample is measured, and the bulk density is calculated by dividing the obtained weight by the internal volume of the meter. In addition, the average particle diameter is measured using a laser diffraction / scattering particle size distribution analyzer (e.g., Horiba Ltd.'s "LA-960V2"), etc. Specifically, the average particle diameter is calculated by performing a wet measurement in which the sample is dispersed in isopropanol solvent and the average particle diameter is measured. This solid may be a primary particle, or it may be a secondary particle formed by an aggregate of primary particles.

[0036] If the solid material is in pellet form, a granular molded body with a diameter or length of about 1 to 10 mm is preferred. The shape of the pelletized solid material is not limited, but it is usually spherical, ellipsoidal, or cylindrical.

[0037] (Outgassing Amount) When this solid is heated at 300°C for 120 minutes, the amount of outgassing is 100 ppb or less by mass relative to the total mass of the solid, when converted to n-hexane. The amount of outgassing 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 outgassing originating from the solid when the solid is heated to 300°C using an HS-GC-MS apparatus, and the method for converting the measured amount of outgassing to the amount of n-hexane, are described in the examples below. Note that when manufacturing a molded body using this solid, the heating time during molding is usually very short compared to the heating time when measuring outgassing, so thermal decomposition of the end groups of the copolymer hardly occurs during the manufacturing of the molded body.

[0038] In order to form a molded article with superior ozone resistance, the amount of outgassing generated, converted to n-hexane, is preferably less than 50 ppb by mass, and more preferably less than 25 ppb by mass, relative to the total mass of the solid. The amount of outgassing generated may also be 0 ppb by mass, relative to the total mass of the solid.

[0039] If the amount of outgassing generated by the solid exceeds a predetermined range, the amount of outgassing can be reduced by performing a fluorination treatment of the copolymer, which involves flowing a fluorinating agent into contact with the solid containing the copolymer. The process of flowing a fluorinating agent into contact with the solid will be described later.

[0040] In this solid, from the viewpoint of ensuring that molded articles formed from this solid have excellent crack resistance, it is preferable that the content of a second copolymer, which contains unit A and units based on hexafluoropropylene but does not contain unit B, is less than 0.5% by mass relative to the total content of the first copolymer and the second copolymer. From the viewpoint of ensuring that molded articles formed from this solid have excellent crack resistance, it is more preferable that the content of the second copolymer is 0% by mass relative to the total content of the first copolymer and the second copolymer. Note that "does not contain unit B" means that the content of unit B relative to the total units of the copolymer is 0.5 mol% or less.

[0041] <Method for Manufacturing Solid Matter> One method for manufacturing this solid matter is to produce a copolymer and then fluorinate the copolymer by flowing a fluorinating agent into contact with the solid matter containing the copolymer. The method for manufacturing this solid matter will be explained below, using as an example a method in which a copolymer is produced and then a fluorinating agent is flowed into contact with the solid matter containing the produced copolymer as a fluorinating treatment.

[0042] The process for producing the copolymer includes 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, with solution polymerization being preferred. In addition to the above monomers, polymerization initiators, polymerization media, and chain transfer agents can be used in the production of the copolymer.

[0043] The polymerization initiator is preferably a radical polymerization initiator with a half-life of 10 hours at a temperature of 0 to 100°C, and more preferably a radical polymerization initiator with a temperature of 20 to 90°C. Specific examples of polymerization initiators include the 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 polymerization initiator used is preferably 0.01 to 0.9 parts by mass, and more preferably 0.05 to 0.5 parts by mass, per 100 parts by mass of monomer.

[0044] Examples of polymerization media include water, organic solvents, and mixed solvents of water and organic solvents. As organic solvents, fluorine-based solvents such as perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers can be used. Specific examples of organic solvents include the polymerization media exemplified in International Publication No. 2013 / 015202. Polymerization media containing water are preferred, and ultrapure water is more preferred.

[0045] The polymerization medium may be used alone or in combination of two or more types. A mixed solvent of water and a fluorinated solvent is preferred as the polymerization medium, and a mixed solvent of water and perfluorocarbon is more preferred. From the viewpoint of suspendability and economic efficiency, the amount of fluorinated solvent used is preferably 10% by mass or more and less than 100% by mass of the total mass of the mixed solvent. The amount of polymerization medium used is preferably 3 times or more by mass ratio of the amount of monomer used, more preferably 5 times or more. Furthermore, 20 times or less is preferred, and 17 times or less is more preferred.

[0046] As chain transfer agents, 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 are used because they have a large chain transfer constant and require small amounts of addition; hydrocarbons such as n-pentane, n-hexane and cyclohexane; CF ２ H ２ Hydrofluorocarbons such as alcohols; 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 preferred. Among these, at least one selected from the group consisting of alcohols, hydrocarbons, and hydrofluorocarbons is preferred, at least one selected from the group consisting of alcohols and hydrocarbons is more preferred, and alcohols are even more preferred, due to their higher chain transfer constant and high stability of the end groups of the copolymer. Among the alcohols, methanol or ethanol is preferred, and methanol is more preferred from the viewpoint of reactivity and availability. Two or more chain transfer agents may be used. The amount of chain transfer agent used is preferably 0.001 times or more by mass ratio to the amount of monomer used, more preferably 0.005 times or more. Also, 5 times or less is preferred, and 4 times or less is more preferred.

[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, polymerizability may be excellent. If the polymerization temperature is 60°C or lower, the number of unstable end groups in the copolymer is easily reduced. The polymerization pressure is preferably 0.5 to 3.0 MPa, and more preferably 0.9 to 2.5 MPa. The polymerization time is preferably 1 to 12 hours.

[0048] If polymerization yields an aqueous dispersion containing the copolymer, the copolymer can be recovered by coagulating, washing, and drying the copolymer contained in the aqueous dispersion. Alternatively, if polymerization yields the copolymer as a slurry, the copolymer can be recovered by removing the slurry from the reaction vessel, washing, and drying it.

[0049] The copolymer obtained by polymerization may be in the form of a powdered solid. Alternatively, the recovered copolymer may be molded into pellet-shaped solids by known methods.

[0050] Pellet-shaped solids can be formed by conventionally known methods. For example, one method for forming pellet-shaped solids is to extrude a fluorinated copolymer while melting it using a single-screw extruder, a twin-screw extruder, or a tandem extruder, and then cut it to 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 manufacturing method, but is preferably between the melting point of the copolymer + 20°C and the melting point of the copolymer + 140°C. Conventional known methods such as strand cutting, hot cutting, underwater cutting, and sheet cutting can be used to cut the copolymer. The obtained pellets may be heated to remove volatile components (degassing). The obtained pellets may also be treated by contacting them with hot water at 30 to 200°C, steam at 100 to 200°C, or hot air at 40 to 200°C.

[0052] Furthermore, if necessary, the composition containing the copolymer obtained by polymerization may be pulverized to produce a powdered solid. Examples of compositions containing copolymers include granules containing copolymers and melt-kneaded products containing copolymers. Pulverization can be carried out using known pulverizers such as rotor mills, hammer mills, turbo mills, and jet mills.

[0053] (Fluorination treatment) Next, as a fluorination treatment, a fluorinating agent is brought into contact with the powdered or pelletized solid containing the copolymer obtained by polymerization. Through the fluorination treatment, the -COOH, -COOCH groups present in the copolymer are removed. ３ ien-CH ２ OH, -COF, -CF=CF ２ , -CONH ２ and -CF ２ A specific functional group consisting of H, -CF ３ This allows for conversion to a specific functional group, thereby reducing the number of specific functional groups and adjusting the number of functional groups in the copolymer within a predetermined range.

[0054] Furthermore, by flowing a fluorinating agent into contact with a solid containing a copolymer, fluorination can be performed while removing by-products and impurities generated during the fluorination process. This reduces the amount of outgassing generated from the solid, and allows for the easy production of a solid with an outgassing amount within a predetermined range. A specific method for flowing a fluorinating agent into contact with a solid includes filling a flow-through column with a powdered or pelletized solid and flowing the fluorinating agent through the flow-through column for a certain period of time while heating the column.

[0055] Examples of fluorinating agents include fluorine radical sources that generate fluorine radicals under fluorination treatment conditions. Examples of the above-mentioned fluorine radical source include F ２ Gas, N ２ F ２ and halogen fluorides (e.g., IF) ５ and CLF ３ Examples include F. ２ The concentration of fluorine radical sources such as gases may be 100% by volume. From a safety standpoint, F ２It is preferable to use a mixed gas obtained by diluting the gas with an inert gas so that the gas concentration is 5 to 50 volume percent (more preferably 15 to 30 volume percent). Examples of the inert gas include nitrogen gas, helium gas, and argon gas, and nitrogen gas is preferred from an economic standpoint.

[0056] In the flow contact of the fluorinating agent, the linear velocity of the fluorinating agent flowing through the reactor is preferably 0.1 to 10.0 cm / second, more preferably 0.5 to 5.0 cm / second, and particularly preferably 0.6 to 4.8 cm / second, in terms of superior removal efficiency of unstable end groups. Furthermore, the amount of fluorinating agent brought into contact with the solid is preferably 0.00025 L / g or more per mass of the solid when converted to standard conditions, in terms of superior stabilization of unstable end groups, more preferably 0.0005 L / g or more, and more preferably 0.032 L / g or less, and more preferably 0.016 L / g or less, in terms of superior utilization efficiency of the fluorinating agent.

[0057] The treatment temperature during the flow contact of the fluorinating agent is preferably below the melting point of the copolymer, more preferably 20 to 240°C, even more preferably 30 to 240°C, particularly preferably 100 to 235°C, and most preferably 150 to 233°C, in terms of superior efficiency in removing unstable end groups. The treatment time during the flow contact of the fluorinating agent is appropriately changed depending on the number of functional groups of the copolymer before fluorination and the desired number of functional groups, but for example, 0.5 to 30 hours is preferred, 1 to 24 hours is more preferred, and 1.5 to 20 hours is even more preferred.

[0058] The solid material into which the fluorinating agent flows is preferably in particulate or pellet form, and more preferably in particulate form, from the viewpoint of being easily fluorinated while removing by-products and impurities generated by the fluorinating treatment, reducing the amount of outgassing of the solid material, and easily producing a solid material with excellent ozone resistance where the amount of outgassing is within a predetermined range. When the solid material is in particulate form, the bulk density of the solid material into which the fluorinating agent flows is preferably 0.1 g / cm³ for better handling. ３ The above is preferable, and 0.2 g / cm³ ３ The above is more preferable, 0.25 g / cm³ ３The above is more preferable. The bulk density of the solid substance with which the fluorinating agent is brought into flow contact is 0.8 g / cm ３ or less, preferably, 0.7 g / cm ３ or less, more preferably, 0.6 g / cm ３ or less, and even more preferably. When the solid substance is in the form of pellets, the bulk density of the solid substance with which the fluorinating agent is brought into flow contact is 0.1 g / cm ３ or more, preferably, 0.2 g / cm ３ or more, more preferably, 0.5 g / cm ３ or more, and even more preferably. The bulk density of the solid substance with which the fluorinating agent is brought into flow contact is 1.5 g / cm ３ or less, preferably, 1.4 g / cm ３ or less, more preferably, 1.3 g / cm ３ or less, and even more preferably.

[0059] It is preferable to further bring an inert gas into flow contact with the solid substance 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 substance can be further reduced. This is presumably because components such as the fluorinating agent and reaction by-products contained in the solid substance 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. From the viewpoint of economy, nitrogen gas is preferable.

[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 / sec, more preferably 0.5 to 10.0 cm / sec, in terms of better removal of the fluorinating agent and reaction by-products. Also, the amount of the inert gas brought into contact with the solid substance is preferably 0.005 L / g or more, more preferably 0.010 L / g or more, per unit mass of the solid substance in terms of better removability of reaction by-products, and preferably 10 L / g or less, more preferably 5 L / g or less, in terms of better productivity and utilization efficiency of the inert gas.

[0062] The treatment temperature in the flow-through contact with an inert gas is preferably below the melting point of the copolymer, more preferably 30 to 240 °C, and even more preferably 100 to 235 °C, in terms of better removal of the fluorinating agent and reaction by-products. The treatment time for the flow-through contact with an inert gas is, for example, 0.5 to 30 hours, and preferably 1 to 24 hours.

[0063] Known treatments such as the above-mentioned pulverization treatment and pelletization treatment may be performed on the solid obtained by the flow-through contact with the fluorinating agent or the flow-through contact with an inert gas. Specifically, a pelletization treatment may be performed on the solid obtained by subjecting a particulate solid to flow-through contact with a fluorinating agent or flow-through contact with an inert gas to obtain a pellet-shaped solid of the present invention. Even in such a case, a solid of the present invention 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") is a method for producing a solid in which a fluorinating agent is brought into flow-through 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 a copolymer containing unit A and unit B, wherein the total number of specific functional groups is less than 150 per 10 ６ carbon atoms in the main chain of the copolymer, to obtain a powdery or pellet-shaped solid containing the copolymer. By this production method, a powdery or pellet-shaped solid containing a copolymer containing unit A and unit B, 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 produce a solid excellent in ozone resistance and capable of forming a molded body.

[0065] In this manufacturing method, the powdered or pelletized solid material and the copolymer contained in the solid material that are subjected to flow contact with the fluorinating agent are as described in the first embodiment, including preferred embodiments, for the solid material and the copolymer contained in the solid material before fluorination treatment, except for the content of specific functional groups and the amount of outgassing. When the powdered or pelletized solid material subjected to flow contact with the fluorinating agent in this manufacturing method is heated to 300°C, the amount of outgassing is usually more than 100 ppb by mass relative to the total mass of the solid material, converted to n-hexane. Furthermore, the number of functional groups in the copolymer contained in the powdered or pelletized solid material subjected to flow contact with the fluorinating agent in this manufacturing method is usually 10 carbon atoms in the main chain of the copolymer. ６ There are over 150 of each.

[0066] The method for bringing a fluorinating agent into contact with a solid containing unit A and unit B in this manufacturing method is as already described in the method for producing a solid according to the first embodiment, including preferred embodiments.

[0067] The solid produced by this manufacturing method preferably has an outgassing amount of 100 ppb by mass or less, converted to n-hexane, relative to the total mass of the solid, more preferably less than 50 ppb by mass, and even more preferably less than 25 ppb by mass. The outgassing amount may also be 0 ppb by mass relative to the total mass of the solid. Other properties of the solid produced by this manufacturing method, including preferred embodiments, are as described for the solid according to the first embodiment.

[0068] [Molded Article] The molded article of the present invention is obtained by molding a solid material according to the first embodiment of the present invention, or a solid material manufactured by the manufacturing method according to the second embodiment of the present invention. Specific examples of the molded article of the present invention include injection molded articles obtained by injection molding of a solid material, extruded articles obtained by extrusion molding, blow molded articles obtained by blow molding, transfer molded articles obtained by transfer molding, press molded articles obtained by press molding, rotational molded articles obtained by rotational molding, and coatings obtained by electrostatic coating. The molded article of the present invention is preferably a press molded article obtained by press molding. Injection molded articles are also preferred because they can be obtained with a beautiful appearance without corroding the mold used for molding.

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

[0070] The solid material, the solid material produced by the manufacturing method according to the second embodiment, or the molded article of the present invention can be used for the following purposes. Fluid transfer components for food manufacturing equipment, such as food packaging films, lining materials, packings, seals, and sheets for fluid transfer lines used in food manufacturing processes; chemical stoppers, packaging films, lining materials, packings, seals, and sheets for fluid transfer lines used in pharmaceutical manufacturing processes; internal lining materials for chemical tanks and piping in chemical plants or semiconductor factories; O-rings, tubes, packings, valve cores, hoses, and seals used in automobile fuel systems and peripheral equipment, as well as fuel transfer components such as hoses and seals used in automobile automatic transmission systems; carburetor flange gaskets, shaft seals, valve stem seals, seals, and hoses used in automobile engines and peripheral equipment, as well as other automobile components such as automobile brake hoses, air conditioning hoses, radiator hoses, and wire insulation materials; semiconductor components such as O-rings, tubes, packings, valve cores, hoses, seals, rolls, gaskets, diaphragms, and fittings for semiconductor manufacturing equipment. Examples include: chemical liquid transfer components for body equipment; paint and ink components such as paint rolls, hoses, tubes, and ink containers for painting equipment; food and beverage transfer components such as tubes or hoses for food and beverages, hoses, belts, gaskets, and fittings, as well as food packaging materials and glass cooking equipment; waste liquid transport components such as tubes and hoses for waste liquid transport; high-temperature liquid transport components such as tubes and hoses for high-temperature liquid transport; steam piping components such as tubes and hoses for steam piping; corrosion-resistant tapes for piping such as tapes wrapped around piping on ship decks, etc.; various coating materials such as wire coating materials, optical fiber coating materials, transparent surface coating materials and backing materials provided on the light incident side surface of photovoltaic elements of solar cells; sliding components such as diaphragms and various gaskets for diaphragm pumps; agricultural films, fuel cell carrier films, and weather-resistant covers for various roofing materials and side walls, etc.; interior materials used in the building sector, and coating materials for glass such as non-combustible fire-resistant safety glass; lining materials such as laminated steel sheets used in the home appliance sector, etc.

[0071] In particular, the molded articles of the present invention can be suitably used as piping components (e.g., pipes, fittings, gaskets, and packings) or tubes for transferring fluids in semiconductor manufacturing equipment. Furthermore, the molded articles of the present invention can be suitably used as wire coating materials. A specific example of use is a coated wire comprising a core wire and a coating layer made of the molded articles of the present invention provided around the core wire. A coated wire having a coating layer made of the molded articles of the present invention has excellent electrical properties because the core wire is resistant to corrosion and the outer diameter hardly changes, and is suitably used as a high-frequency transmission cable, flat cable, heat-resistant cable, etc. Such a coated wire can be manufactured, for example, by melt-extruding a copolymer or this composition onto a core wire to form the coating layer.

[0072] Furthermore, the molded body of the present invention can also be suitably used as a compressible member. A compressible member is a member used in a compressed and deformed state, and the size and shape of the compressible member are appropriately set according to the application. The shape of the compressible member may be, for example, annular. Also, the compressible member may have a circular, oval, or rounded-corner square shape in plan view, and may have a through hole in its center. The compressible member can be used as a piping member for transferring fluids. Furthermore, the compressible member can be used as a member for constituting a non-aqueous electrolyte battery, and is particularly suitable as a member used in contact with the non-aqueous electrolyte in a non-aqueous electrolyte battery. The compressible member can also be suitably used as a sealing member such as a sealing gasket and sealing packing, and as an insulating member such as an insulating gasket and insulating packing. A sealing member is a member used to prevent leakage of liquid or gas, or intrusion of liquid or gas from the outside. An insulating member is a member used to insulate electricity. The compressible member may be a member used for both sealing and insulating purposes.

[0073] The present invention will be described in detail below with reference to examples. Examples 1 and 3-5 are examples, and Examples 2, 6 and 7 are comparative examples. However, the present invention is not limited to these examples. Various measurement and evaluation methods are as follows.

[0074] [Measurement] <Composition of copolymer> The content (mol%) of unit A and unit B in each copolymer is: １９ The molar ratio was calculated by converting the values ​​obtained from F-NMR analysis.

[0075] <Number of Functional Groups N> Using the solids obtained in each example as raw materials, films with a thickness of 0.30 to 0.35 mm were prepared by hot pressing at 330°C. These films were scanned 40 times using a Fourier transform infrared spectrometer (FT-IR, "Spectrum One," PerkinElmer) and analyzed to obtain infrared absorption spectra. Next, the solids obtained in each example were subjected to the fluorination treatment described below for a long period of time to prepare separate base pellets that were completely fluorinated and free of specific functional groups, and base films were obtained in the same manner as above. Next, the difference spectrum between the infrared absorption spectrum of the film obtained by molding the solids in each example and the base spectrum of the base film was obtained. From the absorption peaks of the specific functional groups appearing in this difference spectrum, the number of carbon atoms in the main chain of the copolymer contained in each solid was determined according to formula (A) above. ６ The total number of specific functional groups per individual (number of functional groups N) was calculated.

[0076] <Outgassing Amount> The amount of outgassing 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) instrument. As described below, the amount obtained by subtracting the column-derived components from the total amount of gaseous substances detected by HS-GC-MS analysis and then converting it to the amount of n-hexane was defined as the outgassing amount.

[0077] More specifically, n-hexane was diluted with toluene to prepare n-hexane standard solutions with concentrations of 10 ppb by mass, 100 ppb by mass, 500 ppb by mass, 1000 ppb by mass, and 5000 ppb by mass. Two μL of each standard solution was measured using a microsyringe, the entire volume was placed in a headspace vial, and the vial was sealed. Each standard solution was then measured using the HS-GC-MS apparatus described below under the measurement conditions described below. From the concentration of the standard solution and the integral value of the measured peak area, a straight line passing through the zero point (origin) and represented by the following equation (A1) was derived by a first-order approximation, and the slope a was determined. A = a × X (A1) In equation (A1), A represents the peak area of ​​the detected n-hexane, and X represents the concentration of n-hexane in the measurement sample (unit: ppb by mass).

[0078] Next, 1 g of the solid obtained in each example was placed in a headspace vial, sealed tightly, and analyzed under the same conditions as the n-hexane standard solution described above. After calculating all the peak areas obtained excluding the components derived from the column, the calculated peak areas were summed up. From the sum of the obtained peak areas, the amount of outgassing 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 amount of outgassing (unit: mass ppb) when the solid was 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 shown in formula (A1).

[0079] (HS-GC-MS system) GC unit: Agilent "7890B" MS unit: Agilent "5977B" HS unit: Agilent "7697A" (HS-GC-MS measurement conditions) ・HS Heating temperature: 300℃ Heating time: 120 minutes Pressurization time: 1 minute GC cycle time: 50 minutes Transfer line temperature: 255℃ ・GC Column: DB-1301 (length 60m, inner diameter 0.25mm, film thickness 1μm) Heater (injection row temperature): 255℃ Split ratio: 30 Column flow rate: Total flow: 1 mL / min (helium gas) Oven temperature: Hold at 40℃ for 5 minutes, then increase temperature at 10℃ / min, and hold at 280℃ for 10 minutes (total 39 minutes) ・MS interface temperature: 150℃ Ion source temperature: 230°C; Ionization method: EI; Detection: Scan method; Target ions: m / z = 35-700

[0080] <MFR> For each example, a melt indexer (manufactured by Technoseven Co., Ltd.) was used to measure the mass (g) of the solid that flowed out of a 2 mm diameter, 8 mm length orifice in 10 minutes under ASTM D1238 conditions of a temperature of 372°C and a load of 5 kg, and this was defined as the MFR (g / 10 min).

[0081] [Evaluation Test] <Ozone Resistance> The solid material produced in each example was compressed at 340°C to create a 1 mm thick sheet. A 10 mm x 20 mm sample was cut from the resulting sheet and used as a sample for the ozone exposure test.

[0082] A test apparatus was prepared consisting of an ozone generator (product name: SGX-A11MN (modified), manufactured by Sumitomo Seiki Industries Co., Ltd.), a PFA container containing deionized water, and a PFA cell containing the sample, all connected in this order. Ozone gas (ozone / oxygen volume ratio = 10 / 90) generated by the ozone generator was bubbled through deionized water to add water vapor to the ozone gas. The resulting moist ozone gas was then circulated at a rate of 0.7 liters / minute through the PFA cell containing the sample, thereby exposing the sample to the moist ozone gas. During the ozone exposure test, the temperature was maintained at 40°C and the humidity at 80% RH.

[0083] 180 days after the start of the ozone exposure test, the sample was removed and the sample surface was lightly rinsed with deionized water. Then, the sample surface was photographed using a laser microscope, and the 1 mm surface area was measured. ２ The number of cracks with a length of 1 μm or more and the number of blisters with a major axis of 1 μm or more were measured. The major axis of a blister refers to the maximum diameter of the blister as viewed from the direction normal to the sample surface. Based on the measured number of cracks and blisters, the ozone resistance of each solid was evaluated according to the following evaluation criteria.

[0084] (Ozone resistance evaluation criteria) ◎: Number of cracks is 10 / mm ２ The following applies: The number of blisters is 10 / mm². ２ Below: ○: Number of cracks is 10 / mm ２ The following applies: The number of blisters is 10 / mm². ２ Super △: Number of cracks is 10 / mm ２ Super high quality, with 10 blister packs per mm ２ Below: ×: Number of cracks is 10 / mm ２ Super high quality, with 10 blister packs per mm ２ super

[0085] <Surface Smoothness> The solid material obtained in each example was press-molded at 340°C to obtain a 1 mm thick film. Press molding was performed using a heated press machine (SA-301, manufactured by Tester Sangyo Co., Ltd.). The surface smoothness of the obtained film was confirmed by touch when a finger was placed on the surface of the film and evaluated according to the following criteria.

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

[0087] [Example 1] A polymerization tank with a stirrer and an internal volume of 96.3 L is degassed, and then CF ３ CH ２ OCF ２ CF ２ 27.2 kg of H (AE-3000: product name, manufactured by AGC Corporation), 43.0 kg of water, CF ２ = CFO (CF ２ ) ３2.69 kg of F (PPVE) and 3.484 kg of methanol were placed in the polymerization tank. The temperature inside the polymerization tank was then raised to 50°C (polymerization temperature), and 9.20 kg of tetrafluoroethylene (TFE) was added to raise the pressure inside the polymerization tank to 1.31 MPa (gauge pressure). 80 mL of a 0.2 mass% AE-3000 solution of heptafluorobutyroyl peroxide was added as a polymerization initiator solution to start polymerization, and the polymerization initiator solution was continuously added thereafter. In addition, TFE was continuously added to maintain the pressure during polymerization at the same level as the pressure at the start of polymerization. After 292 minutes from the start of polymerization, when 650 mL of polymerization initiator solution and 13.0 kg of TFE had been added, the temperature inside the polymerization tank was lowered to 15°C, and the tank was purged until the pressure inside the polymerization tank reached 1 atm.

[0088] The obtained copolymer slurry was filtered to separate the polymerization medium, and then dried at 150°C for 15 hours to obtain copolymer X1. １９ F-NMR analysis revealed that the composition of copolymer X1 was 98.55 / 1.45 (mol%). Note that "PPVE units" refer to the CF of each copolymer. ２ = CFO (CF ２ ) ３ It is a unit based on F and is included in unit B. Furthermore, in the analysis of copolymer X1 described above, no units other than PPVE units included in unit B were detected. In addition, the number of functional groups N of copolymer X1 determined according to the above measurement method is 10 carbon atoms in the main chain. ６ There were over 500 of each.

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

[0090] Next, the solid material X1 was fluorinated using the following method. A cylindrical reactor with an inner diameter of 21 mm was prepared, with pipes connected to both ends in the longitudinal direction, so that the gas could flow through the inside of the reactor from one end to the other. The solid material X1 was filled into this reactor, and N ２ After thoroughly purging with gas, the reactor was heated to 230°C. ２ F diluted to 20% by volume with gas ２ The gas was circulated through the reactor at a linear velocity of 10 mm / second for 4 hours, bringing it into contact with the solid X1. During the circulating contact, the pressure inside the reactor was maintained at 1 atmosphere, and the reactor temperature was kept at 230°C.

[0091] Next, while maintaining the pressure inside the reactor at 1 atmosphere and the reactor temperature at 230°C, N2 is introduced into the reactor. ２ By passing gas through and bringing it into contact with the solid X1, a pellet-shaped solid Y1 containing copolymer Y1 was obtained. N was passed through the reactor. ２ The total amount of gas was 1 L per gram of solid X1 (at standard conditions). Also, N was circulated in the reactor. ２ The linear velocity of the gas was 20 mm / second.

[0092] １９ F-NMR analysis revealed that the composition of copolymer Y1 contained in solid Y1 was the same as that of copolymer X1, with unit A / PPVE units = 98.55 / 1.45 (mol%), and no units other than PPVE units (B) were detected. Furthermore, the number of functional groups N of copolymer Y1 was 10 carbon atoms in the main chain. ６ There were 10 or fewer per unit.

[0093] [Example 2] The pelletized solid X1 obtained in Example 1 was placed in a vacuum vibration reactor (manufactured by Okawara Seisakusho Co., Ltd.) and heated to 210°C. After vacuuming, N ２ F diluted to 20% by volume with gas ２ The gas was introduced to 1 atmosphere. Dilution F ２ 0.5 hours after the gas introduction begins, the system is evacuated and then diluted again. ２ Gas was introduced. After another 0.5 hours, the system was vacuumed again, and diluted F was used again. ２ Gas was introduced. From then on, the above dilution F ２ ​The gas introduction and vacuuming operations were performed once every hour, and the solid X1 and diluted F were subjected to a temperature of 210°C for 10 hours. ２ The gas was reacted with the reactor. After the reaction was complete, the reactor was filled with nitrogen. ２ The fluorination treatment was completed by thoroughly purging with gas. The fluorination treatment yielded pellet-shaped solid Y2 containing copolymer Y2. The number of functional groups N of copolymer Y2 contained in solid Y2 is 10 carbon atoms in the main chain. ６ There were over 150 per unit.

[0094] [Example 3] A polymerization tank with a stirrer and 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), and 9.20 kg of TFE was further charged to raise the pressure inside the polymerization tank 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 polymerization, and thereafter the polymerization initiator solution was continuously added. In addition, 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 polymerization initiator solution and 13.0 kg of TFE had been added, the temperature inside the polymerization vessel was lowered to 15°C and the vessel was purged until the pressure inside the polymerization vessel reached 1 atm.

[0095] The obtained copolymer slurry was heated to 90°C while stirring to remove the polymerization medium, then filtered to separate the water, and heated and dried at 150°C for 15 hours to obtain a powdered solid X3 containing copolymer X3. １９ F-NMR analysis revealed that the composition of copolymer X3 was unit A / PPVE unit = 98.55 / 1.45 (mol%). Furthermore, no units other than PPVE units were detected in the analysis of copolymer X3. The number of functional groups N of copolymer X3, determined according to the above measurement method, was 10 carbon atoms in the main chain. ６ There were over 500 particles per unit. Furthermore, according to the measurement method described above, the bulk density of solid X3 was 0.5 g / cm³. ３The average particle size of solid X3 was 250 μm.

[0096] Except for using solid X3 instead of solid X1, the solid X3 was fluorinated in the same manner as in Example 1 to obtain a powdered solid Y3 containing copolymer Y3. １９ The composition of copolymer Y3 and the number of functional groups N of copolymer Y3, as measured by F-NMR analysis, are shown in Table 2 below. Furthermore, no units other than PPVE units were detected in the analysis of copolymer Y3. The bulk density and average particle size of solid Y3 were the same as those of solid X3.

[0097] [Example 4] After fluorinating pelletized solid X1, N is placed in the reactor. ２ In the process of circulating the gas, the reactor temperature is lowered to 20°C before N ２ A pellet-shaped solid material Y4 containing copolymer Y4 was obtained in the same manner as in Example 1, except that gas was passed through it and brought into contact with the solid material X1. １９ The composition of copolymer Y4, as measured by F-NMR analysis, and the number of functional groups N of copolymer Y4 are shown in Table 2 below. Furthermore, in the analysis of copolymer Y4 described above, no units other than PPVE units included in unit B were detected.

[0098] [Example 5] A polymerization tank with a stirrer and 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 to raise the pressure inside the polymerization tank to 1.31 MPa (gauge pressure). 270 mL of a 0.2 mass% AE-3000 solution of heptafluorobutyroyl peroxide was charged as a polymerization initiator solution to start polymerization, and thereafter the polymerization initiator solution was continuously added. In addition, 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 after the start of polymerization, when 1260 mL of polymerization initiator solution and 11.0 kg of TFE were added, the temperature inside the polymerization vessel was lowered to 15°C and the vessel was purged until the pressure inside the polymerization vessel reached 1 atm.

[0099] The obtained copolymer slurry was filtered to separate the polymerization medium, and then dried at 150°C for 15 hours to obtain copolymer X5. １９ F-NMR analysis revealed that the composition of copolymer X5 was unit A / PPVE unit = 94.50 / 5.50 (mol%). Furthermore, no units other than PPVE units were detected in the analysis of copolymer X5. The number of functional groups N of copolymer X5, determined according to the above measurement method, was 10 carbon atoms in the main chain. ６ There were over 1500 items per unit.

[0100] Except for using solid X5 instead of solid X1, solid X5 was fluorinated in the same manner as in Example 1 to obtain pellet-shaped solid Y5 containing copolymer Y5. １９ The composition of copolymer Y5 and the number of functional groups N of copolymer Y5, as measured by F-NMR analysis, are shown in Table 2 below. Furthermore, in the analysis of copolymer Y5 described above, no units other than the PPVE units contained in unit B were detected.

[0101] [Example 6] A pellet-shaped solid X1 containing copolymer X1 was prepared according to the method described in Example 1. Next, the solid X1 was fluorinated using the following method. A cylindrical reactor with an inner diameter of 21 mm was prepared, with pipes connected to both ends in the longitudinal direction, so that gas could flow through the inside of the reactor from one end to the other. The solid X1 was filled into this reactor, and N ２ After thoroughly purging with gas, the reactor was heated to 230°C. ２ F diluted to 20% by volume with gas ２ The gas was circulated through the reactor at a linear velocity of 10 mm / second for 4 hours, bringing it into contact with the solid X1. During the circulating contact, the pressure inside the reactor was maintained at 1 atmosphere, and the reactor temperature was kept at 230°C.

[0102] Next, the mixture was cooled to room temperature without passing an inert gas through it to obtain a pellet-like solid Y6 containing copolymer Y6. １９F-NMR analysis revealed that the copolymer composition in solid Y6 was the same as that of copolymer X1, with unit A / PPVE units = 98.55 / 1.45 (mol%), and no units other than PPVE units (B) were detected. Furthermore, the number of functional groups N in copolymer Y6 was 10 carbon atoms in the main chain. ６ There were 10 or fewer per unit.

[0103] [Example 7] A pellet-shaped solid X1 containing copolymer X1 was prepared according to the method described in Example 1. Next, the solid X1 was fluorinated using the following method. A cylindrical reactor with an inner diameter of 21 mm was prepared, with pipes connected to both ends in the longitudinal direction, so that gas could flow through the inside of the reactor from one end to the other. The solid X1 was filled into this reactor, and N ２ After thoroughly purging with gas, the reactor was heated to 230°C. With the reactor pressure at 1 atmosphere and the reactor temperature at 230°C, N2 was introduced into the reactor. ２ By passing gas through and bringing it into contact with the solid X1, a pellet-shaped solid Y7 containing copolymer Y7 was obtained. N was passed through the reactor. ２ The total amount of gas was 1 L per gram of solid X1 (at standard conditions). Also, N was circulated in the reactor. ２ The linear velocity of the gas was 20 mm / second. １９ F-NMR analysis revealed that the copolymer composition in solid Y7 was the same as that of copolymer X1, with unit A / PPVE units = 98.55 / 1.45 (mol%), and no units other than PPVE units (B) were detected. Furthermore, the number of functional groups N in copolymer Y7 was 10 carbon atoms in the main chain. ６ There were over 150 per unit.

[0104] The table below shows the composition of the copolymers in each example and the evaluation results. The "Number of Functional Groups N" column 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 "500<" in the "Number of Functional Groups N" column for "Copolymer X" in Example 1 indicates that copolymer X (copolymer X1) has 10 carbon atoms in its main chain. ６This means that the total number of specific functional groups per unit was more than 500, and the notation "≤10" in the "Number of Functional Groups N" column for "Copolymer Y" in Example 1 indicates that the main chain carbon number of copolymer Y (copolymer Y1) is 10 ６ This means that the total number of specific functional groups per unit was 10 or less. In the table, the "Unit A (mol%)" column shows the content of unit A relative to the total units contained in the copolymer (unit: mol%). The "Unit B (mol%)" column shows the content of unit B relative to the total units contained in the copolymer (unit: mol%). In the "Outgassing Amount (mass ppb)" column, the notation "25-50" for Examples 1 and 5 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 Examples 1 and 5. The notation "<25" for 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 solids in Example 3. The notation "900" for Example 6 means that the outgassing amount, converted to the amount of n-hexane measured by the above measurement method, was 900 mass ppb relative to the total mass of the solids in Example 6. The notation "70" in Example 7 means that the amount of outgassing, converted to the amount of n-hexane measured by the above measurement method, was 70 mass ppb relative to the total mass of the solid in Example 7.

[0105] In each example, the content of unit A and unit B of copolymer X contained in solid X before fluorination treatment was the same as the content of unit A and unit B of copolymer Y contained in solid Y after fluorination treatment. １９ Analysis by F-NMR revealed that the content of copolymers containing both unit A and hexafluoropropylene-based units was less than 0.1% by mass relative to the total mass of the solids.

[0106]

[0107] As shown in the table above, the functional group number N corresponds to the number of carbon atoms in the main chain of the copolymer. ６It has been confirmed that by using the solid material of the present invention, which has fewer than 150 particles per unit and an outgassing amount of 100 ppb by mass or less relative to the total mass of the solid material when heated to 300°C, it is possible to form molded articles that are less prone to cracking and blistering due to ozone and have excellent ozone resistance (Examples 1 and 3-5). The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2024-203068, filed on November 21, 2024, are incorporated herein by reference as disclosure of the present invention.

Claims

1. A powdered or pelletized solid containing a copolymer comprising unit A based on tetrafluoroethylene and unit B based on a monomer represented by formula (1), wherein -CF = CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of OH functional groups is equal to the number of carbon atoms in the main chain of the copolymer. ６ A solid characterized in that it has fewer than 150 particles per unit, and the amount of outgassing when the solid is heated at 300°C for 120 minutes is 100 ppb by mass or less relative to the total mass of the solid, when converted to n-hexane. 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 according to claim 1, wherein the content of unit A is 97.00 to 99.50 mol% relative to the total units of the copolymer.

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

4. The solid according to claim 1, wherein the melt flow rate of the copolymer, measured under 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 claim 1, wherein the unit B includes a unit based on perfluoro(propyl vinyl ether).

6. A molded article characterized by being obtained by molding a solid material according to any one of claims 1 to 5.

7. A fluorinating agent is passed through and contacted with a powdery or pelletized solid containing a copolymer comprising a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by the formula (1), and in the copolymer, -CF=CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ OH are reduced in the total number of functional groups, and a copolymer comprising the unit A and the unit B, wherein the total number of the functional groups is less than 150 per 10 ６ carbon atoms in the main chain of the copolymer, to obtain a powdery or pelletized solid containing the copolymer. 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. The method for producing a solid according to claim 7, wherein an inert gas is passed through the solid that has been in contact with the fluorinating agent, and the amount of the inert gas passed through is 0.005 L / g or more in volume converted to standard conditions per unit mass of the solid.

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

10. The method for producing a solid according to claim 7, wherein the fluorinating agent is brought into flow contact with the solid at a linear velocity of 0.1 to 10.0 cm / second.

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