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 and is less prone to ozone-induced blistering. [Solution] The solid of the present invention is a unit A based on tetrafluoroethylene and formula (1) (CF2 = CF-O-(CF2) n The monomer represented by -CF3) and equation (2) (CF2 = CF - CF2 - O - (CF2)) n A powdered or pelletized solid containing a copolymer comprising a unit B based on a monomer selected from the group consisting of monomers represented by -CF3), 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 has less than 150 units, and equation (3)(CF3-(CF2) n-1 It substantially does not contain compounds represented by -COOH.

Description

Technical Field

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

Background Art

[0002] As a fluororesin excellent in 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 copolymer containing tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, and having a functional group number of 50 or less per 10 main chain carbon atoms. 6

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 copolymer produced 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] In view of the above problems, an object of the present invention is to provide a solid capable of forming a molded body excellent in ozone resistance, in which blisters due to ozone hardly occur. Another object of the present invention is to provide a method for producing a molded body and a solid.

Means for Solving the Problems

[0006] As a result of intensive studies on the above problems, the present inventors have found that a solid in powder or pellet form containing a copolymer comprising a unit A based on tetrafluoroethylene and a unit B based on a monomer selected from the group consisting of a monomer represented by a specific formula (1) and a monomer represented by formula (2), wherein the total number of functional groups of -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2 and -CH2OH in the copolymer is less than 150 per 10 carbon atoms of the copolymer, and a solid substantially free of a compound represented by a specific formula (3) can be used to form a molded article having excellent ozone resistance, thus arriving at the present invention. 6 That is, the inventors have found that the above problems can be solved by the following constitution.

[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 comprising a unit A based on tetrafluoroethylene and a unit B based on a monomer selected from the group consisting of a monomer represented by formula (1) described below and a monomer represented by formula (2) described below, 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, and the solid is substantially free of a compound represented by formula (3) described below. 6 〔2〕 The solid according to 〔1〕, wherein the content of the unit A is 95.0 to 99.5 mol% based on all units of the copolymer. 〔3〕 The solid according to 〔1〕 or 〔2〕, wherein the content of the unit B is 0.5 to 5.0 mol% based on all units of the copolymer. 〔4〕 The solid according to any one of 〔1〕 to 〔3〕, 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. 〔4〕 The solid according to any one of 〔1〕 to 〔3〕, 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 any one of [1] to [4], wherein the above unit B includes at least one selected from the group consisting of units based on perfluoro(propyl vinyl ether) and units based on perfluoro(propyl allyl ether). [6] A molded article characterized by being obtained by molding a solid material described in any of [1] to [5]. [7] A copolymer comprising a unit A based on tetrafluoroethylene and a unit B based on a monomer selected from the group consisting of monomers represented by formula (1) and monomers represented by formula (2) described later, is subjected to fluorination treatment, and the fluorinated powdered solid is heated at 100 to 250°C for 1 hour or more to obtain a copolymer comprising the above unit A and the above unit B, wherein the total number of functional groups of the copolymer main chain has 10 carbon atoms. 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 bulk density of the powdered solid that undergoes the fluorination treatment is 0.10 to 0.70 g / cm³. 3 The method for producing a solid substance as described in [7]. [9] A method for producing a solid according to [7] or [8], wherein the fluorinated powdered solid is heated under a reduced pressure of 2.0 kPa or less. [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, which is less prone to ozone-induced blistering. 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, which is contained in copolymers. "Monomer B1" is the monomer represented by formula (1) described later, "Monomer B2" is the monomer represented by formula (2) described later, and "Monomer B" is the monomer selected from the group consisting of monomer B1 and monomer B2. "Unit B," "Unit B1," and "Unit B2" are units based on monomer B, monomer B1, and monomer B2, respectively, contained in the copolymer.

[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 0.10 to 0.80 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. In this specification, pressure refers to absolute pressure.

[0013] [First Embodiment: Solid Matter] A solid according to the first embodiment of the present invention (hereinafter also referred to as "the solid") is a powdered or pelletized solid containing a copolymer (hereinafter also referred to as "the copolymer") which contains unit A and unit B and has specific functional groups within a predetermined content range. Furthermore, this solid substance substantially does not contain the compound represented by the specific formula (3).

[0014] By using this solid material, it is possible to form molded articles that are less prone to ozone-induced blistering and have excellent ozone resistance. The detailed reasons for this are not yet clear, but it is presumed to be due to the following reasons. As a result of diligent research, the inventors have found that a compound represented by a specific formula (3) (hereinafter also referred to as "compound (3)") can affect the ozone resistance of molded articles formed using PFA. It is presumed that when ozone, which has strong oxidizing power, comes into contact with compound (3) contained in the molded article, the carboxylic acid portion of compound (3) decomposes due to the ozone, releasing CO2 (decarboxylation reaction), and the resulting CO2 causes foaming (blistering) on ​​the surface of the molded article. Furthermore, it is presumed that the -CF2- group remaining after the decomposition of the carboxylic acid portion of compound (3) reacts with ozone to produce hydrofluoric acid, and that this hydrofluoric acid also contributes to the generation of foaming. The compound (3) in question is presumed to be generated during the PFA manufacturing process, particularly when PFA is fluorinated. In contrast, it is presumed that by using a powdered or pelletized solid containing a copolymer of units A and B, which substantially does not contain compound (3), the generation of CO2 and hydrofluoric acid upon contact with ozone is suppressed, and a molded article with improved ozone resistance can be formed. Furthermore, it is presumed that by fluorinating a powdered solid with a bulk density within a specific range, and then performing a heat treatment at a predetermined temperature for a predetermined time after the fluorination treatment, a molded article that substantially does not contain compound (3) and similarly has improved ozone resistance can be formed. 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 present copolymer in the solid matter is preferably 70% by mass or more and 100% by mass or less, more preferably 90% by mass or more and less than 100% by mass, and even more preferably 99% by mass or more and less than 100% by mass, based on the total mass of the solid matter. When the content of the present copolymer is within the above range, it is easy to produce a molded body excellent in ozone resistance from the solid matter.

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

[0017] The content of unit A is preferably 95.0 to 99.5 mol%, more preferably 97.0 to 99.5 mol%, and even more preferably 98.0 to 99.5 mol%, based on all the units contained in the present copolymer, in terms of more excellent heat resistance.

[0018] Unit B is a unit based on monomer B selected from the group consisting of monomer B1 represented by the following formula (1) and monomer B2 represented by the following formula (2). CF2=CF-O-(CF2) n -CF3(1) CF2=CF-CF2-O-(CF2) n -CF3(2) In formula (1) and formula (2), n represents 1 to 9. In formula (1) and formula (2), n 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 more excellent polymerization reactivity.

[0019] Specific examples of monomer B1 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. Specific examples of monomer B2 include perfluoro(methyl allyl ether), perfluoro(ethyl allyl ether), perfluoro(propyl allyl ether) (PFAE), and perfluoro(butyl allyl ether), with perfluoro(methyl allyl ether), perfluoro(ethyl allyl ether), or PFAE being preferred, and PFAE being more preferred.

[0020] Preferably, monomer B is a monomer B in which n is within the above preferred range, more preferably at least one of the monomers listed as specific examples of monomer B1 and monomer B2 above, even more preferably at least one selected from the group consisting of PMVE, PPVE, perfluoro(methyl allyl ether), perfluoro(ethyl allyl ether), and PFAE, and particularly preferably at least one selected from the group consisting of PPVE and PFAE.

[0021] The content of unit B is preferably 0.5 to 5.0 mol%, more preferably 1.0 to 3.0 mol%, and even more preferably 1.5 to 2.5 mol%, relative to the total units contained in the copolymer, in terms of superior moldability and mechanical properties. 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.

[0022] In this copolymer, the total content of unit A and unit B is preferably 95.5 to 100.0 mol%, more preferably 97.5 to 100.0 mol%, even more preferably 99.0 to 100.0 mol%, and particularly preferably 99.5 to 100.0 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.

[0023] In addition to units A and B, this copolymer may also contain units based on TFE and other monomers copolymerizable with monomer B. Other monomers include, for example, ethylene, vinylidene fluoride (VdF), hexafluoropropylene (HFP), and CX.1 X 2 =CX 3 (CF2) 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 hydrogen atom, a fluorine atom, or a chlorine atom, and n is an integer from 1 to 10. ) Monomers represented by CF2=CF-OCH2-Rf 2 (In the formula, Rf 2 ) represents a perfluoroalkyl group having 1 to 5 carbon atoms. Examples include monomers represented by ). If the copolymer contains units based on other monomers, the content of units based on other monomers is preferably less than 4.5 mol%, more preferably less than 2.5 mol%, more preferably less than 1.0 mol%, and particularly preferably less than 0.5 mol%, relative to the total number of units contained in the copolymer.

[0024] 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 100.0 mol% of the total units contained in the copolymer.

[0025] 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).

[0026] (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 less than 50, more preferably less than 20, and even more preferably 10 or less. The number of functional groups may also be 0.

[0027] 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 sum of the 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.

[0028] 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.

[0029] N = I × K / t (A) I: Absorbance K: Correction coefficient t: Film thickness (mm)

[0030] 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.

[0031] [Table 1]

[0032] 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.

[0033] (Melt flow rate) The MFR of this copolymer is preferably 1.0 to 50.0 g / 10 min, more preferably 3.0 to 45.0 g / 10 min, and even more preferably 5.0 to 40.0 g / 10 min, as it can form molded articles 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 this copolymer is the main component of this solid, and other components have almost no effect on the MFR measurement, the MFR measurement value obtained from the measurement of this solid can be considered as the MFR of this copolymer.

[0034] (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 315.0°C or lower, more preferably 312.0°C or lower, and even more preferably 309.0°C or lower, from the standpoint of excellent low-speed tear strength of the molded article. A specific example of a method for adjusting the melting point of this copolymer to the above range is to adjust the composition of the 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.

[0035] This solid may contain other components besides this copolymer. 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.

[0036] 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 0.10 to 0.80 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. In this specification, 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, the average particle diameter is obtained by a wet measurement method in which the sample to be measured is dispersed in isopropanol solvent and the average particle diameter of the dispersed sample is measured. The powdered solid material may be primary particles, or it may be secondary particles formed by aggregation of primary particles.

[0037] 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.

[0038] This solid substance substantially does not contain the compound represented by the following formula (3) (compound (3)). Formula (3) CF3-(CF2) n-1 -COOH In equation (3), n represents a value between 1 and 9.

[0039] In this specification, "substantially free of the compound represented by formula (3)" means that the content of compound (3) in the solid (total content if two or more types of compound (3) are included; the same applies hereinafter) is less than 250 ppb by mass relative to the total mass of the solid. The content of compound (3) in the solid is preferably less than 150 ppb by mass, and more preferably less than 25 ppb by mass, relative to the total mass of the solid. The content of compound (3) may also be 0 ppb by mass, relative to the total mass of the solid.

[0040] The content of compound (3) in the solid can be measured by extracting the component containing compound (3) from the solid using an alcohol solvent such as methanol, and then analyzing the extract using a liquid chromatography / mass spectrometry (LC-MS) instrument. Details of the method for measuring the content of compound (3) are described in the examples below.

[0041] The content of compound (3) in the solid can be reduced, for example, by fluorinating a powdered solid with a bulk density within a specific range during the manufacturing of the solid, and then by heat-treating the fluorinated powdered solid. Details of the fluorination and heat treatment in the manufacturing of the solid will be described later.

[0042] In this solid, from the viewpoint of providing superior ozone resistance to molded articles formed from this solid, it is preferable that the content of a second copolymer, which includes unit A and a unit based on hexafluoropropylene but does not include unit B, be less than 0.5% by mass, and more preferably 0% by mass, relative to the total content of this 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.

[0043] <Method for manufacturing solid matter> One possible method for producing this solid is to manufacture a copolymer, fluorine the powdered solid containing the manufactured copolymer, and then heat-treat the fluorinated powdered solid. The method for producing this solid substance will be explained using the above method as an example.

[0044] The process for producing the copolymer includes using the above monomers (TFE and monomer B) by known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, with the process of producing it 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.

[0045] 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.

[0046] Polymerization media include water, organic solvents, and mixed solvents of water and organic solvents. Fluorine-based solvents such as perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers can be used as organic solvents. 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.

[0047] 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.

[0048] 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.

[0049] 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, excellent polymerizability can be obtained. If the polymerization temperature is 60°C or lower, the melting point of the copolymer can be improved. 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.

[0050] 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.

[0051] Next, the powdered solid containing the obtained copolymer is subjected to a fluorination treatment. The powdered solid material subjected to the fluorination treatment contains the copolymer described above. The bulk density of the powdered solid material subjected to fluorination treatment is 0.10 to 0.80 g / cm³. 3 Therefore, in terms of superior end-processing efficiency, 0.10~0.75 g / cm³ 3 Preferably, 0.10 to 0.70 g / cm³ 3 More preferably, 0.15-0.70 g / cm³ 3 More preferably, 0.20-0.70 g / cm³ 3 That is particularly preferable.

[0052] If the copolymer obtained by polymerization is a powdered solid, the recovered copolymer may be fluorinated directly. If necessary, the copolymer obtained by polymerization may be pulverized to produce a powdered solid. The pulverization can be carried out using known pulverizers such as rotor mills, hammer mills, turbo mills, and jet mills.

[0053] Alternatively, a composition such as pelletized solids or granules containing a copolymer obtained by polymerization may be produced, and the resulting composition may be pulverized to produce powdered solids. 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. 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 +20°C and +140°C above the melting point of the copolymer. Conventional known methods such as strand cutting, hot cutting, underwater cutting, and sheet cutting can be used to cut the copolymer.

[0054] (Fluorination treatment) Next, as a fluorination treatment, a fluorinating agent is brought into contact with a powdered solid containing the 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.

[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] The processing time for the fluorination treatment is appropriately adjusted depending on the number of functional groups in 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. The treatment temperature in the fluorination treatment is preferably below the melting point of the copolymer, more preferably 20 to 240°C, and even more preferably 100 to 235°C.

[0057] Specific methods for fluorination treatment include, for example, placing a tray containing powdered solid material inside an oven, filling the oven with F2 gas or the above-mentioned mixed gas, and heating for a certain period of time. Another method involves heating a flow-through column filled with powdered solid material while flowing F2 gas or the above-mentioned mixed gas through the column for a certain period of time. From the viewpoint of reaction efficiency, the method of placing a tray containing powdered solid material inside an oven, filling the oven with F2 gas or the above-mentioned mixed gas, and heating for a certain period of time is preferred as a method for fluorination treatment.

[0058] (Heat treatment) Next, the fluorinated powdered solid is subjected to heat treatment. In order to more easily produce this solid, it is preferable to heat the fluorinated powdered solid at 100-250°C for 1 hour or more.

[0059] One specific method of heat treatment is to place a tray containing the fluorinated solid material inside an oven and heat it. The heat treatment temperature is more preferably 100-250°C, and even more preferably 150-200°C. The heat treatment processing time is more preferably 1 to 15 hours, and even more preferably 3 to 10 hours. The heat treatment may be carried out under atmospheric pressure, but it is preferable to carry it out under reduced pressure. When heat treatment is carried out under reduced pressure, the pressure is preferably 2.0 kPa or less, more preferably 1.5 kPa or less, and even more preferably 1.0 kPa or less, from the viewpoint of removal efficiency. When heat treatment is carried out under reduced pressure, the pressure is preferably 0 kPa or higher, from the viewpoint of heating efficiency.

[0060] The solid obtained by the above fluorination treatment and heat treatment may be in powder form. Furthermore, the powdered or pelletized solid may be a solid produced by subjecting the solid obtained by the above-mentioned fluorination treatment and heat treatment to known treatments such as the above-mentioned pelletization treatment and pulverization treatment.

[0061] [Second Embodiment: Method for Producing Solid Matter] A method for producing a solid according to the second embodiment of the present invention (hereinafter also referred to as "this production method") involves fluorinating a powdered solid containing a copolymer containing unit A and unit B, and heating the fluorinated powdered solid at 100 to 250°C for 1 hour or more to obtain a copolymer containing unit A and unit B, wherein the total number of specific functional groups of the copolymer main chain has 10 carbon atoms. 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, either in powder or pellet form, containing a copolymer of unit A and unit B, which can form a molded body with excellent ozone resistance.

[0062] In this manufacturing method, the powdered solid and copolymer contained in the solid that are subjected to fluorination treatment are as described in the first embodiment, including preferred embodiments, except for bulk density. The bulk density of the powdered solid material subjected to the fluorination treatment in this manufacturing method is 0.10 to 0.80 g / cm³. 3 Therefore, in terms of superior heating efficiency, 0.10~0.75 g / cm³ 3 Preferably, 0.10 to 0.70 g / cm³ 3 More preferably, 0.15-0.70 g / cm³ 3 More preferably, 0.20-0.70 g / cm³ 3 That is particularly preferable. Furthermore, in this manufacturing method, the number of functional groups in the copolymer contained in the powdered solid subjected to fluorination treatment is typically 10 carbon atoms in the main chain of the copolymer. 6 There are over 150 of each.

[0063] The method for fluorinating the powdered solid in this manufacturing method is as already described in the fluorination treatment of the solid manufacturing method according to the first embodiment, including preferred embodiments.

[0064] In this manufacturing method, the fluorinated solid is heated at 100-250°C for at least one hour as a heat treatment. The heat treatment temperature is preferably 120-220°C, and more preferably 150-200°C. The heat treatment processing time is preferably 1 to 15 hours, and more preferably 3 to 12 hours. The heat treatment may be carried out under atmospheric pressure, but it is preferable to carry it out under reduced pressure. When heat treatment is carried out under reduced pressure, the pressure is preferably 2.0 kPa or less, more preferably 1.5 kPa or less, and even more preferably 1.0 kPa or less, from the viewpoint of removal efficiency. When heat treatment is carried out under reduced pressure, the pressure is preferably 0 kPa or higher, from the viewpoint of heating efficiency. The specific method of heat treatment, including preferred embodiments, is as already described in the description of the method for heating fluorinated solids in the method for producing solids according to the first embodiment.

[0065] The solid obtained by the above fluorination treatment and heat treatment may be a powdered solid. Furthermore, powdered or pelletized solids may be produced by subjecting the solids obtained by the above-mentioned fluorination treatment and heat treatment (preferably in powdered form) to known treatments such as pelletization and pulverization. The pelletizing and crushing processes are as described in the method for producing solid matter according to the first embodiment, including preferred embodiments.

[0066] It is preferable that the solid produced by this manufacturing method is substantially free of compound (3). That is, it is preferable that the content of compound (3) in the solid produced by this manufacturing method (total content if two or more types of compound (3) are included) is less than 250 ppb by mass relative to the total mass of the solid. By producing the solid using this manufacturing method, it is easy to obtain a solid that is substantially free of compound (3). The content of compound (3) in the solid produced by this manufacturing method is more preferably less than 150 ppb by mass, and even more preferably less than 25 ppb by mass, relative to the total mass of the solid. The content of compound (3) 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.

[0067] [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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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]

[0072] The present invention will be described in detail below with reference to examples. Examples 1, 2, and 5 are examples, and examples 3, 4, and 6 are comparative examples. However, the present invention is not limited to these examples. The various measurement and evaluation methods are as follows.

[0073] [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.

[0074] <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.

[0075] <Content of compound (3)> The solids obtained in each example were freeze-milled using a freeze mill "Freezer Mill 6775" (manufactured by SPEX) under the following conditions. Before freeze-milling, 10% by mass of dibutylhydroxytoluene (BHT) was added to the solids relative to the total mass, and the resulting mixture was freeze-milled to obtain samples of the pulverized material. The conditions for freeze-milling were: solids: 3g, BHT: 0.3g, run time: 5mins, rate: 15cps, cycle: 3. 5 mL of methanol was added to 2.5 g of the obtained pulverized sample. The resulting mixture was sonicated at 50°C for 2 hours and then centrifuged (5000 rpm, 5 minutes) to settle the copolymer contained in the pulverized sample, and the supernatant was collected as the extract.

[0076] LC-MS analysis was performed on each extract under the following conditions to measure and quantify the content of compound (3) in the extract. Specifically, methanol standard solutions were first prepared for five levels of compound (3) whose concentrations were known and within the range of 1 to 10,000 ng / g. From the concentrations of each standard solution and the integral values ​​of the peak areas detected by LC-MS analysis, a straight line passing through the 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 compound (3), and x represents the concentration of compound (3) (ng / g) relative to the total mass in the methanol standard solution.

[0077] Table 2 below shows the measuring instruments and measurement conditions used for LC-MS analysis. Table 3 below shows the parameters for each compound (3) used in LC-MS analysis using the multiple reaction monitoring (MRM) method.

[0078] [Table 2]

[0079] [Table 3]

[0080] Next, LC-MS analysis by MRM was performed on the extracts prepared from the solids obtained in each example using the method described above, under the conditions described above, and the peak area of ​​compound (3) with each carbon number was determined. Subsequently, the content of compound (3) with each carbon number in the extract was calculated using the following formula (A2). XCm ​​= ACm / a (A2) In formula (A2), XCm represents the content (ng / g) of each compound (3) with each number of carbon atoms in the extract, ACm represents the peak area of ​​each compound (3) with each number of carbon atoms detected by LC-MS analysis of the extract, and a represents the slope a obtained by formula (A1) above. The limit of quantification in the above LC-MS analysis was 1 ng / g.

[0081] Next, the content (ZCm) of compound (3) relative to the total mass of the solid obtained in each example was determined using the following formula (A3). ZCm = XCm × ρ1 × La / W1 (A3) In formula (A3), ZCm represents the content of each carbon number compound (3) in the solid, ρ1 represents the density of the extraction solvent (methanol in each example), La represents the volume of the extraction solvent (5 mL in each example), and W1 represents the mass of the solid contained in the extract (2.5 g in each example). The total content of compound (3) in the solid obtained in each example was calculated by summing the content (ZCm) of compound (3) for each carbon number obtained from formula (A3).

[0082] <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).

[0083] [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. The resulting sheets were cut into 10 mm x 20 mm pieces and used as samples for ozone exposure testing.

[0084] 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.

[0085] 180 days after the start of the ozone exposure test, the samples were removed and the sample surface was lightly rinsed with deionized water. Then, the sample surface was photographed using a laser microscope, and the number of blisters with a major axis of 1 μm or larger was counted. The major axis of the blister refers to the maximum diameter of the blister as viewed from the normal direction to the sample surface. Based on the number of blisters counted, the ozone resistance of each solid was evaluated according to the following evaluation criteria.

[0086] (Ozone resistance evaluation criteria) ○: Number of blister packs: 10 / mm 2 below ×: Number of blister packs: 10 / mm 2 super

[0087] [Example 1] CF3CH2OCF2CF2H (AE-3000: product name, manufactured by AGC) (134g), CF2=CFO(CF2)3F(PPVE) (39.8g), methanol (36.1g), ultrapure water (426.7g), and TFE (142g) were added to a 1.2L stainless steel reaction vessel, and the mixture was heated to 50°C (polymerization temperature) while stirring with a stirring blade. 3mL of heptafluorobutyroyl peroxide (PFB) (0.06% by mass, AE-3000 solution) was added to the reaction vessel to start polymerization. As polymerization began, the pressure inside the reaction vessel decreased, so TFE was continuously injected to maintain the pressure at the start of polymerization. 2mL of PFB (0.06% by mass, AE-3000 solution) was added every 10 minutes after the start of polymerization. The polymerization reaction was terminated when the amount of TFE injected reached 160g. The reaction vessel was then cooled, and the remaining TFE was recovered.

[0088] The slurry was removed from the reaction vessel, and the polymerization solvent was recovered using an evaporator. The residue of the obtained slurry was heated at 150°C for 12 hours to obtain a powdered solid X1 containing copolymer X1. 19 F-NMR analysis revealed that the composition of copolymer X1 was unit A / PPVE unit = 98.5 / 1.5 mol%. "PPVE unit" refers to the unit based on the PPVE of each copolymer and is included in unit B1. In the analysis of copolymer X1 described above, no units other than PPVE units included in unit B were detected. 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. Furthermore, measurements taken according to the above measurement method revealed that the bulk density of solid X1 was 0.33 g / mL, and the average particle size of solid X1 was 550 μm.

[0089] <Fluorination treatment> Next, the solid material X1 was fluorinated using the following method. A tray containing solid material X1 was placed in a box-type reaction oven, and the oven was sealed. After reducing the pressure inside the oven, an F2 / N2 mixed gas, prepared by diluting F2 gas with N2 gas to a concentration of 20% by volume, was introduced into the oven. The pressure inside the oven was set to 1 atmosphere (1 atm), and the temperature inside the oven was set to 230°C. One hour after the introduction of the F2 / N2 mixed gas, the pressure inside the oven was reduced, and the F2 / N2 mixed gas was introduced again. The reaction was carried out at 230°C for one hour. After the reaction was completed, heating was stopped, and N2 gas was introduced into the oven to completely replace the F2 / N2 mixed gas inside the oven with N2 gas, thus ending the fluorination treatment.

[0090] <Heat treatment> A mesh tray filled with fluorinated solid material was placed in a box-type reaction oven, and the oven was sealed. The oven was depressurized, and the solid material on the mesh tray was heated at 180°C for 5 hours under a pressure of 1.5 kPa. After heating, the solid material was cooled, and N2 gas was introduced into the oven to replace the gas inside. The pressure inside the oven was increased to 1 atmosphere, and then the oven was opened. The above fluorination treatment and heat treatment yielded a powdery solid Y1 containing copolymer Y1.

[0091] 19 F-NMR analysis revealed that the composition of copolymer Y1 contained in solid Y1 was the same as the composition of copolymer X1. Furthermore, the results measured by the above method showed that the number of functional groups N in copolymer Y1 is 10 carbon atoms in the main chain. 6 The amount per unit was less than 50, and the content of compound (3) in solid Y1 was less than 25 mass ppb relative to the total mass of solid Y1. The bulk density and average particle size of solid Y1 were the same as those of solid X1, respectively.

[0092] [Example 2] 80.5g of CF3CH2OCF2CF2H (AE-3000: product name, manufactured by AGC), 79.6g of CF2=CFCF2OCF2CF2CF3, 12.1g of methanol, and 426.7g of ultrapure water were added to a 1.2L stainless steel reaction vessel, and the mixture was heated to 80°C (polymerization temperature). After adding TFE to the reaction vessel until the pressure inside the vessel reached 1.4 MPaG (gauge pressure), 6 mL of tert-butyl peroxypivalate (0.5% by mass, AE-3000 solution) was added to start polymerization. As polymerization began, the pressure inside the reaction vessel decreased, so TFE was continuously added to maintain the pressure at the start of polymerization. When the amount of TFE added reached 160g, the polymerization reaction was stopped, the reaction vessel was cooled, and the remaining TFE was recovered.

[0093] The slurry was removed from the reaction vessel, and the polymerization solvent was recovered using an evaporator. The residue of the obtained slurry was heated at 150°C for 12 hours to obtain a powdered solid X2 containing copolymer X2. 19 F-NMR analysis revealed that the composition of copolymer X2 was unit A / PFAE unit = 98.5 / 1.5 mol%. "PFAE unit" refers to the unit based on the PFAE of each copolymer and is included in unit B2. In the analysis of copolymer X2 described above, no units other than PFAE units included in unit B were detected. The number of functional groups N of copolymer X2, determined according to the above measurement method, is 10 carbon atoms in the main chain. 6 There were over 500 of each. Furthermore, the bulk density of solid X2 was 0.33 g / mL, and the average particle size of solid X2 was 570 μm.

[0094] Except for using solid X2 instead of solid X1, the solid X2 was subjected to fluorination treatment and heat treatment in the same manner as in Example 1 to obtain a powdered solid Y2 containing copolymer Y2. 19 F-NMR analysis revealed that the composition of copolymer Y2 contained in solid Y2 was the same as the composition of copolymer X2. Furthermore, the results measured by the above method showed that the number of functional groups N in copolymer Y2 is 10 carbon atoms in the main chain. 6 The amount per unit was less than 50, and the content of compound (3) in solid Y2 was less than 25 mass ppb relative to the total mass of solid Y2. The bulk density and average particle size of solid Y2 were the same as those of solid X2.

[0095] [Example 3] A powdery solid X1 containing copolymer X1 was obtained according to the method described in Example 1. The obtained solid X1 was pelletized using an extruder. Specifically, a twin-screw extruder was prepared, equipped with a screw having two kneading sections. Solid material X1 was introduced into the hopper of the feeder of the twin-screw extruder, and the material 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 strand discharged from the vent section was slowly cooled and cut with a pelletizer to produce pellet-shaped solid material X3 containing copolymer X1. The shape of the solid material X3 was cylindrical, 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.

[0096] 19 F-NMR analysis revealed that the composition and number of functional groups N of copolymer X1 contained in solid X3 were the same as those of copolymer X1 contained in solid X1. Furthermore, the bulk density of solid X3 was 1.26 g / mL.

[0097] The obtained solid X3 was subjected to a fluorination treatment according to the fluorination treatment method described in Example 1 to obtain pellet-shaped solid Y3 containing copolymer Y3. 19 F-NMR analysis revealed that the composition of copolymer Y3 was identical to that of copolymer X1 contained in solid X3. Furthermore, the results measured by the above method showed that the number of functional groups N in copolymer Y3 is 10 carbon atoms in the main chain. 6 The amount per unit was less than 50, and the content of compound (3) in solid Y3 was 5000 ppb by mass relative to the total mass of solid Y3.

[0098] [Example 4] Except for using pelletized solid X3 produced in Example 3 instead of solid X1, the solid X3 was subjected to fluorination treatment and heat treatment in the same manner as in Example 1 to obtain pelletized solid Y4 containing copolymer Y4. 19 F-NMR analysis revealed that the composition of copolymer Y4 was identical to that of copolymer X1 contained in solid X3. Furthermore, the results measured by the above method showed that the number of functional groups N in copolymer Y4 is 10 carbon atoms in the main chain. 6 The amount was less than 50 particles per unit, and the content of compound (3) in solid Y4 was 3000 ppb by mass relative to the total mass of solid Y4.

[0099] [Example 5] A powdered solid Y1 containing copolymer Y1 was obtained according to the method described in Example 1. Next, the obtained solid Y1 was pelletized using an extruder according to the pelletization method for solid X1 in Example 3. This produced pelletized solid Y5 containing copolymer Y5. The solid Y5 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. The composition and number of functional groups N of copolymer Y5 contained in solid Y5 were the same as those of copolymer Y1 contained in solid Y1. Furthermore, the content of compound (3) in solid Y5 was the same as that of compound (3) in solid Y1.

[0100] [Example 6] A powdered solid Y6 containing copolymer Y6 was obtained by the same method as in Example 1, except that only a fluorination treatment was performed on the obtained powdered solid X1, and no heat treatment was performed. 19 F-NMR analysis revealed that the composition of copolymer Y6 contained in solid Y6 was the same as the composition of copolymer X1. Furthermore, the results measured by the above method showed that the number of functional groups N in copolymer Y6 is 10 carbon atoms in the main chain. 6 The amount per unit was less than 50, and the content of compound (3) in solid Y6 was 5500 ppb by mass relative to the total mass of solid Y6. The bulk density and average particle size of solid Y6 were the same as those of solid X1, respectively.

[0101] The table below shows the copolymer composition, solid material properties, and evaluation results for each example. 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 X1 has 10 carbon atoms in its main chain. 6 This means that the total number of specific functional groups per unit was 500 or more, and the notation "<50" in the "Number of Functional Groups N" column for "Copolymer Y" indicates that the main chain carbon number of copolymer Y1 is 10 6 This means that the total number of specific functional groups per individual was less than 50. The "Unit A (mol%)" column, the "Unit B1 (mol%)" column, and the "Unit B2 (mol%)" column show the content of Unit A (in mol%), Unit B1 (in mol%), and Unit B2 (in mol%) relative to the total units contained in the copolymer, respectively. The "Compound (3) (mass ppb)" column for "Solid Matter Y" shows the content (mass ppb) of Compound (3) relative to the total mass of Solid Matter Y.

[0102] In each example, the content of units A, B1, and B2 of copolymer X contained in solid X before fluorination treatment was the same as the content of units A, B1, and B2 of copolymer Y contained in solid Y after fluorination treatment.

[0103] [Table 4]

[0104] As shown in the table above, a powdered or pelletized solid containing a copolymer containing unit A and unit B, wherein the number of functional groups N is 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 contains fewer than 150 particles per unit and substantially does not contain compound (3), it is possible to form molded articles that are less prone to ozone-induced blistering and have excellent ozone resistance (Examples 1, 2, and 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 selected from the group consisting of monomers represented by formula (1) and monomers represented by formula (2), -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 substance characterized by being substantially free of the compound represented by formula (3). Formula (1) CF ２ = CF - O - (CF ２ ) ｎ - CF ３ Formula (2) CF ２ = CF - CF ２ -O-(CF ２ ) ｎ -CF ３ Equation (3) CF ３ - (CF) ２ ) ｎ－１ -COOH In equations (1) to (3), n represents 1 to 9.

2. The solid according to claim 1, wherein the content of unit A is 95.0 to 99.5 mol% relative to the total units of the copolymer.

3. The solid according to claim 1, wherein the content of unit B is 0.5 to 5.0 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 comprises at least one selected from the group consisting of units based on perfluoro(propyl vinyl ether) and units based on perfluoro(propyl allyl 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 powdered solid containing a copolymer comprising a unit A based on tetrafluoroethylene and a unit B based on a monomer selected from the group consisting of monomers represented by formula (1) and monomers represented by formula (2) is subjected to fluorination treatment. The fluorinated powdered solid is heated at 100 to 250°C for 1 hour or more to obtain a copolymer containing unit A and unit B, wherein the total number of functional groups of the copolymer has 10 carbon atoms in the main chain. 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. Formula (1) CF ２ = CF - O - (CF ２ ) ｎ - CF ３ Formula (2) CF ２ = CF - CF ２ -O-(CF ２ ) ｎ -CF ３ In equations (1) and (2), n represents a value between 1 and 9.

8. The bulk density of the powdered solid subject to the fluorination treatment is 0.10 to 0.70 g / cm³. ３ The method for producing a solid substance according to claim 7.

9. A method for producing a solid according to claim 7 or 8, wherein the fluorinated powdered solid is heated under reduced pressure of 2.0 kPa or less.

Images