Solid matter, molded body, method for manufacturing solid matter

Abstract

The present invention aims to provide a solid material, a molded article, and a method for producing 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. [Solution] The solid of the present invention is a powder or pelletized solid comprising a copolymer containing unit A based on tetrafluoroethylene and unit B based on a monomer represented by formula (1) (CF2=CF-O-Rf), wherein the total number of functional groups -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH is such that the main chain of the copolymer has 10 carbon atoms. 6 Each unit contains less than 150 particles, and the amount of outgassing when the above solid is heated at 300°C for 120 minutes is 100 ppb or less by mass relative to the total mass of the above solid, when converted to n-hexane.

Description

Technical Field

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

Background Art

[0002] As a fluororesin having excellent mechanical properties, chemical properties, electrical properties, etc. and 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 body of PFA is used as a pipe material for a semiconductor manufacturing apparatus, further improvement in ozone resistance is required for the molded body. When the present inventors evaluated a molded body formed using the PFA described in Patent Document 1, they found that the ozone resistance did not meet the higher required level recently demanded and further improvement was necessary.

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

Means for Solving the Problems

[0006] As a result of intensive studies on the above problems, the inventors have found that a solid in powder or pellet form containing a copolymer containing 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 possessed by 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 based on the total mass of the solid in terms of n-hexane, and have found that a molded body excellent in ozone resistance can be formed by using such a solid, thus leading to the present invention.

[0007] That is, the inventors have found that the above problems can be solved by the following constitution. 〔1〕 A solid in powder or pellet form containing a copolymer containing a unit A based on tetrafluoroethylene and a unit B based on a monomer represented by the formula (1) described later, 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 based on the total mass of the solid in terms of n-hexane. 〔2〕 The solid according to 〔1〕, wherein the content of the unit A is 97.00 to 99.50 mol% based on 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% based on 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 a solid material described in any of [1] to [5]. [7] A fluorinating agent is passed through a solid material in powder or pellet form containing a copolymer comprising unit A based on tetrafluoroethylene and unit B based on a monomer represented by formula (1) described later, thereby reducing the total number of functional groups -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH in the copolymer, and the copolymer containing unit A and unit B, wherein the total number of functional groups is such that 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] The solid material that has been in contact with the above-mentioned fluorinating agent is then brought into contact with an inert gas. The method for producing a solid according to [7], wherein the amount of the inert gas brought into contact with the solid 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 [8], wherein the processing temperature during the flow contact of the inert gas is 30 to 240°C. [Effects of the Invention]

[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. [Modes for carrying out the invention]

[0009] The meanings of the terms used in this specification are as follows: A numerical range represented using "~" 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, which is 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) 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] "Specific functional group" refers to a functional group included in the group consisting of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH. 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 material with an average particle size of 3000 μm or less and a bulk density of 0.1 to 0.8 g / cm³. 3 It means an object that is [a certain type of object]. "Pellet-shaped solids" refers to granular molded products manufactured by extruding and cutting solid materials.

[0013] [First Embodiment: Solid Matter] The solid according to the first embodiment of the present invention (hereinafter also referred to as "the solid") comprises 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 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.

[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 caused by ozone. The detailed reasons for this are not yet clear, but it is presumed to be due to the following reasons. The above outgassing amount 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, end groups of copolymers contained in the solid material, by-products of fluorination treatment, and impurities. It is presumed that these components undergo thermal decomposition during heating at 300°C for 120 minutes, becoming gaseous substances. 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 blistering on the surface of the molded body. In contrast, it is presumed that a molded body formed using this solid material, in which the outgassing amount when heated at 300°C for 120 minutes is below a predetermined value, can suppress oxidative decomposition when in 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 equal to the number of carbon atoms in the main chain of the copolymer. 6 It is presumed that the presence of fewer than 150 cells per unit suppresses the oxidative decomposition of specific functional groups by ozone. Thus, it is presumed that a molded product with excellent ozone resistance was obtained by satisfying each of these requirements.

[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 monomers 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 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 standpoint of superior polymerization reactivity. Perfluoroalkyl groups may be linear or branched. When a perfluoroalkyl group has an etheric oxygen atom between carbon atoms, the number of etheric oxygen atoms is preferably 1 to 3, and 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. This copolymer may contain two or more units B. If this copolymer contains two or more units B, it means that the total content of the two or more units 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 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%, and 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, this copolymer preferably contains no units based on the above 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 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) In this copolymer, the total number of specific functional groups belonging to the group consisting of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH is equal to the number of carbon atoms in this copolymer. 6 The number is less than 150 per unit. From the standpoint 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 also be 0.

[0026] Specific functional groups are functional groups located at the ends of the main chain or side chains of the copolymer, and functional groups located within the main chain or side chains. The number of functional groups is the total number of specific functional groups. Specific functional groups are introduced into the copolymer, for example, by chain transfer agents or polymerization initiators used in the production of the copolymer. More specifically, when an alcohol is used as a chain transfer agent, or when a peroxide having the structure -CH2OH is used as a polymerization initiator, -CH2OH is introduced to the main chain ends of the copolymer. Alternatively, the functional groups can be introduced to the side chain ends of the copolymer by polymerizing monomers having the functional groups. Furthermore, if the number of functional groups in a copolymer having a specific functional group exceeds a predetermined range, the number of functional groups can be reduced by fluorinating the copolymer and converting the specific functional group to a -CF3 terminal group. The number of functional groups in the copolymer can be adjusted by changing the conditions of the fluorination treatment (e.g., treatment time, etc.) described later.

[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 using 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 completely fluorinated copolymer that 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 units N per individual.

[0028] N = I × K / t (A) I: Absorbance K: Correction coefficient 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] [Table 1]

[0031] In copolymers, the absorption frequencies of -CH2CF2H, -CH2COF, -CH2COOH, -CH2COOCH3, and -CH2CONH2 are calculated by subtracting several tens of Kaiser (cm) from the respective absorption frequencies of -CF2H, -COF, -COOH (free and bonded), -COOCH3, and -CONH2 shown in the table. -1 ) It will become lower. For example, the number of -COFs is such that the absorption frequency due to -CF2COF is 1883 cm⁻¹. -1 The number of functional groups determined from the absorption peak and the absorption frequency of 1840 cm² due to -CH2COF -1 This is the sum of the number of functional groups determined from the absorption peaks.

[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, in order to form a molded article with a good balance of folding resistance and flexural strength. A specific example of a method to bring the MFR of this copolymer within 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 a copolymer refers to the mass (g) of copolymer flowing out of a 2mm diameter, 8mm length orifice in 10 minutes, measured under ASTM D1238 conditions of 372°C and a 5kg load. Furthermore, since copolymers are the main component of solid matter, and other components have little effect on MFR measurement, the MFR measurement obtained from measuring solid matter 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 standpoint 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 at a rate of 10°C / min in an air atmosphere 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 the copolymer, heat stabilizers, antioxidants, colorants, UV absorbers, fillers, crosslinking agents, crosslinking aids, and organic peroxides. If 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, per 100 parts by mass of the copolymer.

[0035] This solid material may be in powder form or pellet form. This powdered solid has an average particle size of 3000 μm or less and a bulk density of 0.1 to 0.8 g / cm³. 3 It is a particle. 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. Furthermore, the average particle diameter is measured using a laser diffraction / scattering particle size distribution analyzer (for example, the "LA-960V2" manufactured by Horiba, Ltd.). Specifically, a wet measurement is performed in which the sample is dispersed in isopropanol solvent and the average particle diameter is measured to calculate the average particle diameter. This solid material may be primary particles, or it may be secondary particles formed by the aggregation of primary particles.

[0036] If the solid material is in pellet form, a granular molded body with a diameter or length of approximately 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, converted to n-hexane, is 100 ppb or less relative to the total mass of the solid. The amount of outgassing generated when a solid is heated at 300°C for 120 minutes can be measured using a headspace GC-MS (HS-GC-MS) instrument. Details of the method for measuring outgassing originating from solids generated when a solid is heated to 300°C using an HS-GC-MS instrument, and the method for converting the measured amount of outgassing to the amount of n-hexane, are described in the examples below. Furthermore, when manufacturing molded articles using this solid, the heating time during molding is usually very short compared to the heating time used when measuring outgassing. Therefore, thermal decomposition of the end groups of the copolymer hardly occurs during the manufacturing of the molded articles.

[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 mass ppb, and more preferably less than 25 mass ppb, relative to the total mass of the solid. The amount of outgassing generated may also be 0 mass ppb 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 containing unit A and a unit based on hexafluoropropylene, but not 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. Furthermore, "does not contain unit B" means that the amount of unit B relative to the total units of the copolymer is 0.5 mol% or less.

[0041] <Method for manufacturing solid matter> One possible method for producing this solid is to manufacture a copolymer and then fluorinate the copolymer by passing a fluorinating agent through contact with the solid containing the copolymer. The method for producing this solid is described below, using as an example a method in which a copolymer is produced and a fluorinating agent is passed through contact with the solid containing the produced copolymer as a fluorination 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 the process of producing by solution polymerization being preferred. In the production of copolymers, in addition to the monomers mentioned above, polymerization initiators, polymerization media, and chain transfer agents can be used.

[0043] The polymerization initiator is preferably a radical polymerization initiator with a half-life of 10 hours and a temperature range of 0 to 100°C, and more preferably a radical polymerization initiator with a temperature range of 20 to 90°C. Specific examples of polymerization initiators include the various polymerization initiators exemplified in International Publication No. 2013 / 015202. Polymerization initiators may be used individually 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 used.

[0044] 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. 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 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, it is preferably 20 times or less, and more preferably 17 times or less.

[0046] Preferred chain transfer agents include 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, due to their large chain transfer constants and the small amount of additive required; 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. In particular, at least one selected from the group consisting of alcohols, hydrocarbons, and hydrofluorocarbons is preferred, more preferably at least one selected from the group consisting of alcohols and hydrocarbons, and even more preferably alcohols, due to their higher chain transfer constant and greater stability of the end groups of the copolymer. Among the alcohols, methanol or ethanol is preferred, with methanol being 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 of the amount of monomer used, more preferably 0.005 times or more. Furthermore, 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. Polymerizability can be excellent at a polymerization temperature of 15°C or higher. At a polymerization temperature of 60°C or lower, the number of unstable end groups in the copolymer can be 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 it 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 treatment). The obtained pellets may also be treated by contacting them with hot water at 30-200°C, steam at 100-200°C, or hot air at 40-200°C.

[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 molten kneaded products containing copolymers. Grinding can be carried out using known grinding machines 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 a powdered or pelletized solid containing a copolymer obtained by polymerization. Fluorination treatment can convert specific functional groups in the copolymer, consisting of -COOH, -COOCH3, -CH2OH, -COF, -CF=CF2, -CONH2, and -CF2H, to -CF3. This reduces the number of specific functional groups, allowing the number of functional groups in the copolymer to be adjusted 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. Specific methods for flow-through contact of fluorinating agents include filling a flow-through column with a powdered or pelletized solid material, and then flowing the fluorinating agent through the 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 such fluorine radical sources include F2 gas, N2F2, and halogenated fluorides (e.g., IF5 and ClF3). The concentration of the fluorine radical source, such as F2 gas, may be 100% by volume. From a safety standpoint, it is preferable to use a mixed gas obtained by diluting F2 gas with an inert gas so that the concentration is 5-50% by volume (more preferably 15-30% by volume). Examples of the inert gas include nitrogen gas, helium gas, and argon gas, and from an economic standpoint, nitrogen gas is preferred.

[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, and more preferably 0.5 to 5.0 cm / second, in that it provides better 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, more preferably 0.0005 L / g or more, per mass of the solid when converted to standard conditions, in terms of superior stabilization of unstable end groups. In terms of superior utilization efficiency of the fluorinating agent, it is preferably 0.032 L / g or less, and more preferably 0.016 L / g or less.

[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, and particularly preferably 100 to 235°C, in terms of superior removal efficiency of unstable end groups. The treatment time for 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 is preferably 0.5 to 30 hours, with 1 to 24 hours being preferred.

[0058] The solid material to which the fluorinating agent is passed through 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 fluorination 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. The bulk density of the solid material into which the fluorinating agent is applied is 0.1 g / cm³, which offers better handling. 3 The above is preferable, 0.2 g / cm³ 3The above is more preferable. The bulk density of the solid material into which the fluorinating agent is flowed is 0.8 g / cm³, which provides better removal efficiency of unstable end groups. 3 The following is preferable: 0.7 g / cm³ 3 The following are preferable.

[0059] It is preferable to further expose the solid material, which has been exposed to the above-mentioned fluorinating agent, to an inert gas. By exposing the solid material to an inert gas after exposure to the fluorinating agent, the amount of outgassing from the solid material can be further reduced. This is presumed to be because the exposure to the inert gas removes components such as the fluorinating agent and reaction by-products contained in the solid material.

[0060] Examples of inert gases used for flow contact include nitrogen gas, helium gas, and argon gas, with nitrogen gas being preferred from an economic standpoint.

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

[0062] The processing temperature during the flow contact with the 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 superior removal of the fluorinating agent and reaction by-products. The treatment time for the flow contact with the inert gas is, for example, 0.5 to 30 hours, and preferably 1 to 24 hours.

[0063] The solid material obtained by flow contact with a fluorinating agent or flow contact with an inert gas may be subjected to known treatments such as the pulverization and pelletization treatments described above. Specifically, the solid material obtained by flowing a fluorinating agent or an inert gas into particulate solid material may be subjected to a pelletizing process to obtain pelletized solid material. In this case as well, solid material with an outgassing amount within a predetermined range can be obtained.

[0064] [Second Embodiment: Method for Producing Solid Matter] A method for producing solids according to a second embodiment of the present invention (hereinafter also referred to as "this production method") involves flow-contacting a fluorinating agent with a powdered or pelletized solid containing a copolymer containing unit A and unit B, thereby reducing the total number of specific functional groups in the copolymer, and the copolymer containing unit A and unit B, wherein the total number of specific functional groups is such that the main chain carbon number of the copolymer is 10 6 This is a method for producing a solid substance, which involves obtaining a powdered or pelletized solid substance containing a copolymer with fewer than 150 units per unit. This manufacturing method makes it possible to produce a solid material in the form of a powder or pellet containing a copolymer of unit A and unit B, which generates little outgassing when heated to 300°C, is less prone to cracking and blistering due to ozone, and can form a molded body with excellent ozone resistance.

[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, except for the content of specific functional groups and the amount of outgassing. In this manufacturing method, when the powdered or pelletized solid material to which the fluorinating agent is passed into flow contact is heated to 300°C, the amount of outgassing is typically more than 100 ppb by mass relative to the total mass of the solid material, when converted to n-hexane. Furthermore, in this manufacturing method, the number of functional groups in the copolymer contained in the powdered or pelletized solid that is subjected to flow contact with the fluorinating agent is typically 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 flow 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 above 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 body] 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 produced by the manufacturing method according to the second embodiment of the present invention. Specific examples of the molded articles 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, rotationally molded articles obtained by rotational molding, and coatings obtained by electrostatic coating. Press-molded articles obtained by press molding are preferred among the molded articles of the present invention. 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 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 body of the present invention can also be suitably used as a wire coating material. A specific example of its use is a coated wire comprising a core wire and a coating layer made of the molded body of the present invention, provided around the core wire. A coated wire equipped with a coating layer made of the molded body of the present invention has excellent electrical properties because the core wire is resistant to corrosion and its outer diameter hardly changes, and is therefore 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 article 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. Alternatively, the compressible member may have a circular, oval, or rounded-corner quadrilateral shape in plan view, and may have a through hole in its center. The compressible member can be used as a piping component for transferring fluids. Furthermore, the compressible member can be used as a component for constructing a non-aqueous electrolyte battery, and is particularly suitable as a component 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 also be a member used for both sealing and insulating purposes. [Examples]

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

[0074] [measurement] <Composition of copolymer> The content (mol%) of units A and B in each copolymer is: 19 The molar ratio was calculated by converting the results obtained from 1F-NMR analysis.

[0075] <Number of functional units N> The solid materials obtained in each example were molded using a hot press at 330°C to produce films with a thickness of 0.30 to 0.35 mm. 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. Then, 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 main chain carbon number 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 generated 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 of outgassing was determined 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.

[0077] More specifically, n-hexane was diluted with toluene to prepare n-hexane standard solutions with concentrations of 10 mass ppb, 100 mass ppb, 500 mass ppb, 1000 mass ppb, and 5000 mass ppb. 2 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 sample (unit: mass ppb).

[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 equation (A2), XCm represents the amount of outgassing (in mass ppb) when a 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 shown in equation (A1).

[0079] (HS-GC-MS device) GC section: Agilent “7890B” MS section: Agilent “5977B” HS section: 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 line temperature): 255℃ Split ratio: 30 Column flow rate: Total flow: 1 mL / min (helium gas) Oven temperature: Hold at 40°C for 5 minutes, then increase the temperature at 10°C / minute until it reaches 280°C, then hold for 10 minutes (total 39 minutes). ·MS Interface temperature: 150℃ Ion source temperature: 230℃ 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 2mm diameter, 8mm length orifice in 10 minutes under ASTM D1238 conditions of 372°C and a load of 5kg, and this was defined as MFR (g / 10min).

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

[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 filled with deionized water, and a PFA cell containing the sample, 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 through the PFA cell containing the sample at a rate of 0.7 liters / minute, 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: 10 / mm 2 The following applies: The number of blisters is 10 / mm². 2 below ○: Number of cracks: 10 / mm 2 The following applies: The number of blisters is 10 / mm². 2 super △: Number of cracks: 10 / mm 2 Super and blister packs number 10 / mm 2 below ×: Number of cracks: 10 / mm 2 Super and blister packs number 10 / 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. The press molding was performed using a heated press machine (SA-301, manufactured by Tester Industries Co., Ltd.). The surface smoothness of the obtained film was confirmed by touch when a finger was placed on the film surface 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 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 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 to maintain the pressure during polymerization 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.

[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 A / PPVE = 98.55 / 1.45 (mol%). The "PPVE unit" is a unit based on CF2 = CFO(CF2)3F for each copolymer and is included in unit B. Furthermore, no units other than PPVE units included in unit B were detected in the analysis of copolymer X1. Furthermore, 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 coaxial twin-screw extruder was prepared, equipped with a screw having two kneading sections. Copolymer X1 was introduced into the feeder hopper of the twin-screw extruder, and kneaded under conditions of a cylinder temperature of 380°C and a screw rotation speed of 100 rpm, while suction from the vent section was performed using 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 piping connected to both ends along its length, allowing gas to flow through the reactor from one end to the other. Solid material X1 was packed into the reactor, and after thorough displacement with N2 gas, the reactor was heated to 230°C. F2 gas, diluted to 20% by volume with N2 gas, was flowed into the reactor at a linear velocity of 10 mm / second for 4 hours, bringing it into contact with solid material X1. During the flow and contact period, 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 gas was circulated through the reactor and brought into contact with the solid X1 to obtain pellet-shaped solid Y1 containing copolymer Y1. The total amount of N2 gas circulated in the reactor was 1 L per gram of solid material X1 (at standard conditions). The linear velocity of the N2 gas circulating in the reactor 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 unit = 98.55 / 1.45 (mol%), and no unit B other than PPVE unit was detected. Furthermore, the number of functional groups N in copolymer Y1 is 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, F2 gas diluted to 20% by volume with N2 gas was introduced to 1 atmosphere. 0.5 hours after the start of introducing the diluted F2 gas, the reactor was vacuumed and the diluted F2 gas was introduced again. After another 0.5 hours, the reactor was vacuumed again and the diluted F2 gas was introduced again. Thereafter, the above operations of introducing the diluted F2 gas and vacuuming were continued once every hour, and the solid X1 and diluted F2 gas were reacted at a temperature of 210°C for 10 hours. After the reaction was completed, the reactor was thoroughly replaced with N2 gas to complete the fluorination treatment. The fluorination treatment yielded pelletized solid Y2 containing copolymer Y2. The number of functional groups N in 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, which are included in unit B, were detected in the analysis of copolymer X3. Furthermore, the number of functional groups N of copolymer X3, determined according to the above measurement method, is 10 carbon atoms in the main chain. 6 There were over 500 of each. Furthermore, according to the measurement method described above, the bulk density of solid X3 was found to be 0.5 g / cm³. 3 The average particle size of solid material X3 was 250 μm.

[0096] Except for using solid X3 instead of solid X1, solid X3 was fluorinated in the same manner as in Example 1 to obtain 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 1F-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] In the step of circulating N2 gas through a reactor after fluorinating pelletized solid X1, the reactor temperature was lowered to 20°C before circulating the N2 gas and bringing it into contact with the solid X1. Except for this step, pelletized solid Y4 containing copolymer Y4 was obtained in the same manner as in Example 1. 19 The composition of copolymer Y4, as measured by 1F-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 included in unit B other than PPVE units 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, raising 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 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.

[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, which are included in unit B, were detected in the analysis of copolymer X5. Furthermore, the number of functional groups N of copolymer X5, determined according to the above measurement method, is 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, as measured by 1F-NMR analysis, and the number of functional groups N of copolymer Y5 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] The table below shows the composition of the copolymers for 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. 6 This 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 copolymer Y (copolymer Y1) has 10 carbon atoms in its main chain. 6 This means that the total number of specific functional groups per individual 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: mole%). The "Unit B (mol%)" column shows the content of unit B relative to the total units contained in the copolymer (unit: mole%). 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 to 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.

[0102] 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. Also, the solids in each example 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.

[0103] [Table 2]

[0104] 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. 6 It 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 or less by mass 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).< / mfr>

Claims

1. A powdered or pelletized solid containing a copolymer comprising a unit A based on tetrafluoroethylene and a unit 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 equal to the number of carbon atoms in the main chain of the copolymer. ６ Each unit contains less than 150 units. A solid material characterized in that the amount of outgassing when the solid material is heated at 300°C for 120 minutes is 100 ppb by mass or less relative to the total mass of the solid material, 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 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 formula (1) is brought into flow contact with a fluorinating agent, and in the copolymer, -CF=CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of functional groups of OH is reduced, and the copolymer comprises the unit A and the unit B, and the total number of the functional groups is less than 150 per 10 ６ carbon atoms in the main chain of the copolymer. A method for producing a solid, characterized by obtaining a solid in powder or pellet form 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 solid material that has been in contact with the fluorinating agent is then exposed to an inert gas. The method for producing a solid product according to claim 7, wherein the amount of the inert gas brought into contact with the solid product is 0.005 L / g or more in volume converted to standard conditions per unit mass of the solid product.

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.

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