Solid composition, extrusion molded article, blow molded article, transfer molded article, press molded article, injection molded article, coated electric wire, and molded article

Abstract

Provided is a solid composition that exhibits low discoloring properties and low foaming properties, that has a low thermal weight loss rate, and that can be used to form a molded article that is excellent in tensile strength, folding resistance, flexural strength, and flexural modulus after a thermal aging test.　The solid composition includes: a copolymer containing a unit based on tetrafluoroethylene and a unit based on a perfluoro(alkyl vinyl ether); and a metallic element. In the copolymer, the contained amount of the unit based on tetrafluoroethylene is 96.10 to 97.10 mass% in relation to all units contained in the copolymer, and the contained amount of the unit based on a perfluoro(alkyl vinyl ether) is 2.90 to 3.90 mass% in relation to all units contained in the copolymer. The total number of functional groups, namely -CF=CF2, -CF2H, -COF, -COOH, -COOCH3, -CONH2, and -CH2OH of the copolymer, is 50 or less per 106 carbon atoms of the copolymer. The melt flow rate of the solid composition as measured under the condition of a temperature of 372°C in compliance with ASTM D1238 is 11.0 to 22.0 g / 10 minutes. The melting point of the copolymer is 298.0°C or higher, and the contained amount of the metallic element is 0.0100 to 2.0000 ppm by mass in relation to the total mass of the solid composition.

Description

Solid compositions, extrusion molded articles, blow molded articles, transfer molded articles, press molded articles, injection molded articles, coated electric wires, and molded articles

[0001] The present invention relates to solid compositions, extrusions, blow molded articles, transfer molded articles, press molded articles, injection molded articles, coated wires and molded articles.

[0002] Copolymers of tetrafluoroethylene and perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PFA") are known as melt-processable fluororesins that are excellent in mechanical, chemical, and electrical properties. For example, Patent Document 1 discloses a copolymer containing tetrafluoroethylene units and perfluoro(propyl vinyl ether) units, in which the content of perfluoro(propyl vinyl ether) units is 2.0 to 2.8 mass% based on the total monomer units, and which has a melt flow rate of 23 to 30 g / 10 min.

[0003] Japanese Patent Application Laid-Open No. 2022-058290

[0004] When PFA is used as a constituent material of a molded article, the molded article is required to exhibit low colorability, low foaming property, and low rate of weight loss on heat, as well as excellent properties such as mechanical strength, etc. When the present inventors evaluated molded articles formed using the PFA described in Patent Document 1, they found that there was room for improvement in colorability, foaming property, rate of weight loss on heat, and mechanical strength (particularly, tensile strength, folding endurance, flexural strength, and flexural modulus after heat aging tests).

[0005] Therefore, an object of the present invention is to provide a solid composition that can be used to form molded articles that exhibit low coloration and foaming properties, have a low rate of thermal weight loss, and are excellent in tensile strength, folding endurance, flexural strength, and flexural modulus after a heat aging test. Another object of the present invention is to provide extrusion-molded articles, blow-molded articles, transfer-molded articles, press-molded articles, injection-molded articles, coated electric wires, and molded articles.

[0006] As a result of extensive research into the above-mentioned problems, the present inventors have discovered a solid composition comprising a copolymer containing units based on tetrafluoroethylene and units based on perfluoro(alkyl vinyl ether), and a metal element, wherein the content of the units based on tetrafluoroethylene in the copolymer is 96.10 to 97.10 mass% based on all units contained in the copolymer, and the content of the units based on perfluoro(alkyl vinyl ether) is 2.90 to 3.90 mass% based on all units contained in the copolymer, and the -CF=CF contained in the copolymer ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of OH functional groups is 10 ６ The inventors have found that by using a solid composition characterized by: the number of particles per particle is 50 or less; the melt flow rate of the solid composition measured at 372°C in accordance with ASTM D1238 is 11.0 to 22.0 g / 10 min; the melting point of the copolymer is 298.0°C or higher; and the metal element content is 0.0100 to 2.0000 ppm by mass relative to the total mass of the solid composition, it is possible to form a molded article that exhibits low coloration and low foaming properties, a low rate of thermal weight loss, and excellent tensile strength, folding endurance, flexural strength, and flexural modulus after a heat aging test, and have completed the present invention.

[0007] That is, the inventors have found that the above-mentioned problems can be solved by the following constitution: [1] A solid composition containing a copolymer containing units based on tetrafluoroethylene and units based on perfluoro(alkyl vinyl ether), and a metal element, wherein the content of the units based on tetrafluoroethylene in the copolymer is 96.10 to 97.10 mass% based on all units contained in the copolymer, and the content of the units based on perfluoro(alkyl vinyl ether) is 2.90 to 3.90 mass% based on all units contained in the copolymer, and the -CF=CF contained in the copolymer ２ , -CF ２ H, -COF, -COOH, -COOCH３ , -CONH ２ and -CH ２ The total number of OH functional groups is 10 ６ a solid composition having 50 or less particles per solid, a melt flow rate of 11.0 to 22.0 g / 10 min measured at 372°C in accordance with ASTM D1238, a melting point of 298.0°C or higher, and a content of the metal element of 0.0100 to 2.0000 ppm by mass relative to the total mass of the solid composition. [2] The solid composition according to [1], wherein the perfluoro(alkyl vinyl ether) is perfluoro(propyl vinyl ether). [3] An extrusion-molded article obtained by extrusion molding the solid composition according to [1] or [2]. [4] A blow-molded article obtained by blow-molding the solid composition according to [1] or [2]. [5] A transfer-molded article obtained by transfer-molding the solid composition according to [1] or [2]. [6] A press-molded article obtained by press-molding the solid composition according to [1] or [2]. [7] An injection-molded article obtained by injection molding the solid composition according to [1] or [2]. [8] A coated electric wire comprising a conductor and a coating layer disposed on the surface of the conductor and obtained by molding the solid composition according to [1] or [2]. [9] A molded article obtained by molding the solid composition according to [1] or [2], wherein the molded article is a piping member, an electric wire coating material, a tube, a film, or a compressed member.

[0008] According to the present invention, there is provided a solid composition capable of forming a molded article that exhibits low coloration and foaming properties, a low rate of thermal weight loss, and excellent tensile strength, folding endurance, flexural strength, and flexural modulus after a heat aging test. Furthermore, according to the present invention, there are provided an extrusion molded article, a blow molded article, a transfer molded article, a press molded article, an injection molded article, a coated electric wire, and a molded article.

[0009] The meanings of terms used in this specification are as follows: A numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0010] The term "unit" refers collectively to an atomic group derived from one molecule of the above-mentioned monomer, which is formed directly by polymerizing the monomer, and an atomic group obtained by chemically converting a part of the above-mentioned atomic group. In the following, in some cases, a unit derived from an individual monomer will be referred to by the name of the monomer followed by "unit." A "TFE unit" is a unit based on tetrafluoroethylene contained in the copolymer. A "PAVE unit" is a unit based on perfluoro(alkyl vinyl ether) contained in the copolymer, and a "PPVE unit" is a unit based on perfluoro(propyl vinyl ether) contained in the copolymer. A "specific functional group" refers to a group such as -CF=CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The term "functional group number" refers to the total number of specific functional groups contained in the copolymer, unless otherwise specified.

[0011] [Present Solid Composition] The solid composition of the present invention (hereinafter also referred to as "present solid composition") comprises a copolymer (hereinafter also referred to as "present copolymer") containing TFE units and PAVE units within a predetermined range, and a metal element within a predetermined range. The present copolymer also contains a specific functional group within a predetermined content range. The present solid composition also has a melt flow rate (hereinafter also referred to as "MFR") measured at 372°C according to ASTM D1238 within a predetermined range. The term "solid composition" refers to a composition that is solid at 25°C. The content of the present copolymer is preferably 70% by mass or more but less than 100% by mass, more preferably 90% by mass or more but less than 100% by mass, and even more preferably 99% by mass or more but less than 100% by mass, based on the total mass of the present solid composition. When the content of the present copolymer is within the above range, the composition is likely to be a solid composition. Furthermore, the present solid composition is likely to have excellent low coloration and low foaming properties. Furthermore, the solid composition can be easily formed into a molded article that has a low rate of weight loss on heat and is excellent in tensile strength, folding endurance, flexural strength and flexural modulus after a heat aging test.

[0012] By using this solid composition containing this copolymer, it is possible to form a molded article that exhibits low coloration and foaming properties, a low rate of thermal weight loss, and excellent tensile strength, folding endurance, flexural strength, and flexural modulus after a heat aging test. While the details of the reasons for this are not yet clear, it is presumed to be due to the following reasons. Specifically, a PAVE unit content of 3.90% by mass or less, relative to the total units contained in the copolymer, provides moderate rigidity, thereby improving the tensile strength of the molded article after a heat aging test. Furthermore, a PAVE unit content of 2.90% by mass or more, relative to the total units contained in the copolymer, provides excellent flexibility and elongation, thereby improving the flexural modulus of the molded article. An MFR of 11.0 g / 10 min or more is presumed to improve the fluidity of the solid composition when melted, thereby providing excellent moldability of the solid composition and improving the flexural strength of the molded article. Furthermore, an MFR of 22.0 g / 10 min or less is presumed to increase strength, thereby improving the folding endurance of the molded article. The total number of specific functional groups contained in the copolymer is 10 or less than the total number of carbon atoms of the copolymer. ６ It is presumed that by having 50 or less groups per unit mass, decomposition from the terminal functional groups is suppressed, thereby reducing the thermal weight loss rate of the molded article. It is presumed that by having the metal element content of the solid composition be 0.0100 ppm by mass or more, relative to the total mass of the solid composition, a crosslinking reaction occurs within the solid composition via the metal element, thereby improving heat resistance and resulting in a molded article with low foaming properties. It is also presumed that by having the metal element content of the solid composition be 2.0000 ppm by mass or less, relative to the total mass of the solid composition, the metal element is easily dispersed uniformly within the solid composition, resulting in a molded article with low coloration. Furthermore, the melting point of the copolymer is 298.0°C or higher, which means that it is not a so-called elastomer. An elastomer is a copolymer without a melting point. It is presumed that by satisfying these requirements, a molded article was obtained that exhibited low coloration and low foaming properties, a low thermal weight loss rate, and excellent tensile strength, folding endurance, flexural strength, and flexural modulus after heat aging testing.

[0013] <Present Copolymer> The present solid composition includes the present copolymer. The present copolymer includes TFE units and PAVE units.

[0014] The content of TFE units is 96.10 to 97.10% by mass relative to all units contained in the copolymer. From the viewpoint of flexural modulus, the content of TFE units is preferably 96.10 to 96.65% by mass, more preferably 96.41 to 96.55% by mass, relative to all units contained in the copolymer. Furthermore, from the viewpoint of tensile strength after heat aging test, the content of TFE units is preferably 96.41 to 96.90% by mass, more preferably 96.50 to 96.90% by mass, and even more preferably 96.80 to 96.90% by mass, relative to all units contained in the copolymer.

[0015] As the PAVE, a monomer represented by formula (1) is preferred. CF ２ ═CF—O—Rf １ (1) In formula (1), Rf １ represents a perfluoroalkyl group having 1 to 10 carbon atoms. １ From the viewpoint of superior polymerization reactivity, the number of carbon atoms in the perfluoroalkyl group represented by the formula (I) is preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 5, and particularly preferably 1 to 3. The perfluoroalkyl group may be linear or branched.

[0016] Specific examples of PAVE 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.

[0017] The content of PAVE units is 2.90 to 3.90% by mass, based on all units contained in the copolymer. From the viewpoint of flexural modulus, the content of PAVE units is preferably 3.35 to 3.90% by mass, and more preferably 3.45 to 3.80% by mass, based on all units contained in the copolymer. From the viewpoint of tensile strength after heat aging testing, the content of PAVE units is preferably 2.90 to 3.59% by mass, more preferably 3.10 to 3.59% by mass, even more preferably 3.10 to 3.50% by mass, and particularly preferably 3.10 to 3.20% by mass, based on all units contained in the copolymer. The copolymer may contain two or more types of PAVE units. When the copolymer contains two or more types of PAVE units, this means that the total content of the two or more types of PAVE units is within the above range.

[0018] In the present copolymer, the total content of TFE units and PAVE units is 99.00 to 100.0 mass% based on all units contained in the present copolymer, and the total content of TFE units and PAVE units is preferably 99.9 to 100.0 mass% based on all units contained in the present copolymer, since the resulting molded article is less likely to be easily deformed by compression or tension.

[0019] In addition to the TFE unit and the PAVE unit, the copolymer may contain units based on other monomers copolymerizable with TFE and PAVE. Examples of such other monomers include ethylene, vinylidene fluoride (VdF), hexafluoropropylene (HFP), and CX. １ X ２ =CX ３ (CF ２ ) ｎ X ４ (In the formula, X １ , X ２ and X ３ each 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. ２ =CF-OCH ２ -Rf ２ (wherein, Rf ２represents a perfluoroalkyl group having 1 to 5 carbon atoms. When the present copolymer contains units based on other monomers, the content of the units based on other monomers is preferably less than 0.4 mass% based on the total units contained in the present copolymer.

[0020] In order to obtain better abrasion resistance during repeated use, the copolymer preferably does not contain units derived from the other monomers and contains only TFE units and PAVE units. In this case, the total content of TFE units and PAVE units is 100.0% by mass based on the total units contained in the copolymer.

[0021] The contents of the TFE units, the PAVE units and the units based on other monomers in the copolymer are as follows: １９ It can be measured by a known method such as F-NMR (nuclear magnetic resonance analysis).

[0022] (Melt Flow Rate) The MFR of the present copolymer is 11.0 to 22.0 g / 10 min, preferably 11.0 to 21.0 g / 10 min, from the viewpoint of forming a molded article having a good balance of folding endurance and flexural strength. From the viewpoint of folding endurance, the MFR of the present copolymer is preferably 11.0 to 14.0 g / 10 min. From the viewpoint of flexural strength, the MFR of the present copolymer is preferably 16.0 to 21.0 g / 10 min. A specific example of a method for adjusting the MFR of the present copolymer within the above range is a method of adjusting the molecular weight of the present copolymer. The higher the molecular weight of the present copolymer, the smaller the MFR. The MFR of the copolymer refers to the mass (g) of the copolymer flowing from an orifice with a diameter of 2 mm and a length of 8 mm in 10 minutes, measured at a temperature of 372°C and a load of 5 kg according to ASTM D1238.

[0023] (Number of Functional Groups) The present copolymer has a total number of specific functional groups that is equal to or greater than 10 carbon atoms of the present copolymer. ６ The number of particles per particle is 50 or less, and from the viewpoint of forming a molded product having better heat resistance, the number is preferably 10 or less, and more preferably 6 or less.

[0024] The specific functional groups are functional groups present at the main chain terminal or side chain terminal of the copolymer, and functional groups present in the main chain or side chain, and the number of functional groups is the total number of specific functional groups. The specific functional groups are introduced into the copolymer by, for example, a chain transfer agent or a polymerization initiator used in the production of the copolymer. More specifically, when an alcohol is used as a chain transfer agent or when -CH ２ When a peroxide having an OH structure is used, the main chain terminal of the copolymer is formed with -CH ２ OH is introduced. Furthermore, by polymerizing a monomer having a functional group, the functional group is introduced into the side chain terminal of the present copolymer. Furthermore, when the number of functional groups of the present copolymer having a specific functional group exceeds a predetermined range, the number of functional groups can be reduced by fluorinating the present copolymer. The number of functional groups of the present copolymer can be adjusted by changing the conditions of the fluorination treatment (e.g., treatment time, etc.) described below.

[0025] Infrared spectroscopy can be used to identify the type of functional group in the copolymer and measure the number of functional groups. Specifically, the number of functional groups is measured by the following method. First, the copolymer is molded by hot pressing at 330°C to produce a film with a thickness of 0.30 to 0.35 mm. This film is analyzed by Fourier transform infrared spectroscopy to obtain an infrared absorption spectrum of the copolymer. Separately, an infrared absorption spectrum (base spectrum) of a completely fluorinated copolymer with no specific functional groups present is obtained, and a difference spectrum between the infrared absorption spectrum of the copolymer and the base spectrum is obtained. From the absorption peaks of the specific functional groups appearing in this difference spectrum, the number of functional groups in the copolymer having 10 carbon atoms can be determined according to the following formula (A): ６ The number of functional groups per molecule, N, is calculated.

[0026] N = I x K / t (A) I: absorbance K: correction coefficient t: film thickness (mm)

[0027] The absorption frequency, molar absorption coefficient, and correction factor for a specific functional group are shown in Table 1. The molar absorption coefficient of a specific functional group is determined from FT-IR (Fourier transform infrared spectroscopy) measurement data of a low molecular weight model compound.

[0028]

[0029] In this copolymer, -CH ２ CF ２ H, —CH ２ COF, -CH ２ COOH, -CH ２ COOCH ３ and -CH ２ CONH ２ The absorption frequency of -CF is shown in the table. ２ H, -COF, -COOH (free and bonded), -COOCH ３ , and -CONH ２ From each absorption frequency, several tens of Kaiser (cm －１ ) becomes lower. For example, the number of -COF becomes lower. ２ Absorption frequency due to COF: 1883 cm －１ The number of functional groups determined from the absorption peak of -CH ２ Absorption frequency due to COF: 1840 cm －１ The number of functional groups is the sum of the number of functional groups determined from the absorption peaks of the compounds.

[0030] (Melting Point) The melting point of the present copolymer is 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 the present copolymer is preferably 310.5°C or lower, more preferably 310.0°C or lower, and even more preferably 309.5°C or lower, in order to achieve excellent low-speed tear strength of the molded article. A specific example of a method for adjusting the melting point of the present copolymer within the above range is a method of lowering the polymerization temperature during production of the present copolymer. The melting point of the present 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 differential scanning calorimeter.

[0031] <Metal Element> The present solid composition contains a metal element. The metal element is not particularly limited as long as it is a metal element that can be measured by inductively coupled plasma mass spectrometry (ICP-MS) described below, and examples thereof include 29 types of metal elements (Fe, Na, K, Li, Be, Mg, Al, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Mo, Ag, Cd, In, Sn, Cs, Ba, Pb, and Bi).

[0032] The content of the metal element is 0.0100 to 2.0000 ppm by mass, preferably 0.1000 to 2.0000 ppm by mass, and more preferably 0.3000 to 1.8000 ppm by mass, relative to the total mass of the solid composition, from the viewpoint of obtaining a molded product having a well-balanced excellent heat resistance and low coloration. The content of the metal element can be measured, for example, by ICP-MS as described below. When measuring the 29 metal elements, the content of the metal elements in the solid composition is determined by placing the solid composition in a platinum crucible, ashing it in a high-temperature electric heating furnace, treating it with white sulfuric acid, dissolving it in dilute nitric acid, and then measuring the resulting solution using an inductively coupled plasma mass spectrometer (ICP-MS 7500cs (product name), manufactured by Agilent Technologies) by the absolute calibration curve method to determine the total content of the 29 metal elements (Fe, Na, K, Li, Be, Mg, Al, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Mo, Ag, Cd, In, Sn, Cs, Ba, Pb, and Bi).

[0033] The metal elements in the present solid composition are derived from, for example, metal elements contained in materials (e.g., monomers, polymerization solvents, etc.) used in the production of the copolymer. Therefore, a method for adjusting the content of metal elements can be, for example, by using a material with a low content of metal elements in the production method of the present solid composition described below. As a result of various studies on the production method of the present solid composition, the present inventors have found that, particularly for the polymerization medium (e.g., water) used in copolymerizing TFE and PFAV, it is important to use a polymerization medium (e.g., ultrapure water) with a low content of metal elements, and that the characteristics of such a polymerization medium significantly affect the content of metal elements in the solid composition. In addition to the above, the present inventors have found that, in the polymerization of monomers, the metal element content of the resulting solid composition can be reduced by reducing the total content (concentration, mass%) of monomers (e.g., PAVE) and polymerization solvents other than water (e.g., methanol) in the polymerization vessel before adding the polymerization initiator.

[0034] <Other Components> The present solid composition may contain other components in addition to those described above. Specific examples of such other components include resins other than the present copolymer, heat stabilizers, antioxidants, colorants, UV absorbers, fillers, crosslinking agents, crosslinking aids, and organic peroxides. When the present solid composition contains other components, the content of the other components is preferably 0.0000001 to 70 parts by mass, more preferably 0.0000005 to 60 parts by mass, and even more preferably 0.000001 to 50 parts by mass, per 100 parts by mass of the present copolymer.

[0035] [Method for producing the present solid composition] The method for producing the present solid composition is not particularly limited as long as it is a method for producing the present solid composition described above. The method for producing the present solid composition preferably includes a step of producing the present copolymer described below.

[0036] The process for producing the present copolymer includes a process of producing the present copolymer by using the above-mentioned monomers (TFE and PAVE) by known methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, and the process of producing the present copolymer by solution polymerization is preferred. In the production of the present copolymer, in addition to the above-mentioned monomers, a polymerization initiator, a polymerization medium and a chain transfer agent can be used.

[0037] The polymerization initiator is preferably a radical polymerization initiator having a half-life of 10 hours at a temperature of 0 to 100°C, and more preferably a radical polymerization initiator having the temperature of 20 to 90°C. Specific examples of the polymerization initiator include the various polymerization initiators exemplified in WO 2013 / 015202. The polymerization initiator may be used alone or in combination of two or more types. The amount of the polymerization initiator used is preferably 0.01 to 0.9 parts by mass, more preferably 0.05 to 0.5 parts by mass, per 100 parts by mass of the amount of the monomer used.

[0038] The polymerization medium may be water, an organic solvent, or a mixed solvent of water and an organic solvent. As the organic solvent, a fluorine-based solvent such as perfluorocarbon, hydrofluorocarbon, or hydrofluoroether may be used. Specific examples of the organic solvent include the polymerization medium exemplified in International Publication No. 2013 / 015202. As the polymerization medium, a polymerization medium containing water is preferred, and ultrapure water is more preferred.

[0039] In order to facilitate the production of the present solid composition or present copolymer having a low metal element content, the metal element content of water is preferably 2.0 ppm by mass or less, more preferably 1.0 ppm by mass or less, even more preferably 0.5 ppm by mass or less, and particularly preferably 0.1 ppm by mass or less. The lower limit is preferably 0 ppb by mass or more. The method for achieving the above metal element content is not particularly limited, and examples include methods of reducing the metal element content by filtering the water through various filters. The metal element content in water can be measured by an absolute calibration curve method using ICP-MS, similar to the method for measuring the metal element content in the present solid composition described above. The electrical conductivity of water is preferably 1.00 μS / cm or less, more preferably 0.08 μS / cm or less. The lower limit is preferably 0 μS / cm or more. The magnitude of the electrical conductivity of water is related to the amount of metal element in water; the greater the amount of metal element, the greater the electrical conductivity of water. The electrical conductivity of water can be measured by known measurement methods.

[0040] The polymerization medium may be used alone or in combination of two or more. As the polymerization medium, a mixed solvent of water and a fluorine-based solvent is preferred, and a mixed solvent of water and a perfluorocarbon is more preferred. From the viewpoint of suspension property and economic efficiency, the amount of the fluorine-based solvent used is preferably 10% by mass or more and less than 100% by mass based on the total mass of the mixed solvent. The amount of the polymerization medium used is preferably 3 times or more, more preferably 5 times or more, by mass ratio relative to the amount of the monomer used. Also, it is preferably 20 times or less, more preferably 17 times or less.

[0041] As the chain transfer agent, alcohols such as methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3,3-hexafluoroisopropanol, and 2,2,3,3,3-pentafluoropropanol are preferred because they have a large chain transfer constant and can be added in small amounts; hydrocarbons such as n-pentane, n-hexane, and cyclohexane; CF ２ H ２ Preferred are hydrofluorocarbons such as acetone, 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. Among these, at least one selected from the group consisting of alcohols, hydrocarbons, and hydrofluorocarbons is preferred, from the viewpoint of a higher chain transfer constant and high stability of the end groups of the copolymer, more preferably at least one selected from the group consisting of alcohols and hydrocarbons, and even more preferably alcohols. As the alcohol, methanol or ethanol is preferred, and methanol is more preferred from the viewpoint of reactivity and availability. Two or more chain transfer agents may be used. The amount of chain transfer agent used is preferably 0.001 times or more, more preferably 0.005 times or more, by mass ratio relative to the amount of monomer used. Also, it is preferably 5 times or less, more preferably 4 times or less.

[0042] The polymerization temperature is preferably 15 to 60°C, more preferably 20 to 58°C, and even more preferably 25 to 55°C. When the polymerization temperature is 25°C or higher, the polymerizability can be excellent. When 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, more preferably 0.9 to 2.5 MPa. The polymerization time is preferably 1 to 12 hours.

[0043] When an aqueous dispersion containing the copolymer is obtained by polymerization, the copolymer can be recovered by coagulating the copolymer contained in the aqueous dispersion, washing, and drying. When the copolymer is obtained as a slurry by polymerization, the copolymer can be recovered by removing the slurry from the reaction vessel, washing, and drying. By drying, the copolymer can be recovered in powder form.

[0044] The copolymer obtained by polymerization may be subjected to a fluorination treatment to obtain the present copolymer. ３ , -CH ２ OH, -COF, -CF=CF ２ , -CONH ２ and -CF ２ A specific functional group consisting of H is represented by -CF ３ This allows the number of specific functional groups to be reduced, making it easy to adjust the number of functional groups in the present copolymer to fall within a predetermined range.

[0045] The fluorination treatment is carried out by contacting the copolymer that has not been fluorinated with a fluorine-containing compound. The fluorine-containing compound may be a fluorine radical source that generates fluorine radicals under the conditions of the fluorination treatment. The fluorine radical source may be F ２ Gas, N ２ F ２ and halogen fluorides (e.g., IF ５ and ClF ３ etc.)

[0046] F ２ The concentration of the fluorine radical source, such as a gas, may be 100% by volume. ２It is preferable to use a mixed gas obtained by diluting with an inert gas so that the gas concentration is 5 to 50% by volume (preferably 15 to 30% by volume). Examples of the inert gas include nitrogen gas, helium gas, and argon gas, and nitrogen gas is preferred from the viewpoint of economy.

[0047] The temperature during the fluorination treatment is preferably equal to or lower than the melting point of the copolymer, more preferably 20 to 240°C, and even more preferably 100 to 235°C. The fluorination treatment may be carried out by contacting the present copolymer in a molten state with a fluorine-containing compound. As a specific method for the fluorination treatment, for example, a shelf on which pellets of the copolymer are placed is placed in an oven, and the inside of the oven is heated to F ２ An example of such a method is to fill a column packed with copolymer pellets with a gas or the above-mentioned mixed gas, and then heat the column for a certain period of time. Another example is to pass a gas or the above-mentioned mixed gas through a flow column packed with copolymer pellets for a certain period of time while heating the column. The treatment time for the fluorination treatment varies appropriately depending on the number of functional groups in the copolymer before the fluorination treatment, the target number of functional groups, and the fluorination treatment method, but is, for example, 0.5 to 30 hours, and preferably 1 to 24 hours. The present copolymer is preferably produced by obtaining a copolymer by polymerization, and then subjecting the obtained copolymer to the above-mentioned fluorination treatment.

[0048] It is preferable not to use compounds containing metal elements as compounds used in the polymerization (monomer components, polymerization initiators, emulsifiers, chain transfer agents, pH adjusters, etc., excluding aqueous media), since this makes it easier to obtain the present solid composition having a low content of metal elements.

[0049] The method for producing the present solid composition may include a step of melt-kneading the present copolymer and the above-mentioned components, which are used as needed, by a known method.

[0050] [Molded Article] The molded article of the present invention can be obtained by molding the present solid composition. Specific examples of the molded article of the present invention include injection molded articles obtained by injection molding, extrusion molded articles obtained by extrusion molding, blow molded articles obtained by blow molding, transfer molded articles obtained by transfer molding, press molded articles obtained by press molding, rotational molded articles obtained by rotational molding, and coating films obtained by electrostatic coating. The molded article of the present invention is preferably a press molded article obtained by press molding. Furthermore, injection molded articles obtained by injection molding are also preferred because injection molded articles with beautiful appearance can be obtained without corroding the mold used for molding.

[0051] The molded article of the present invention may be in the form of pellets or powder, for example. Pellets of the copolymer can be molded by conventional methods. Examples of pellet-forming methods include extruding the copolymer while melting it using a single-screw extruder, twin-screw extruder, or tandem extruder, cutting it to a predetermined length, and molding it into pellets. The extrusion temperature during melt extrusion varies depending on the melt viscosity of the copolymer and the production method, but is preferably between the melting point of the copolymer + 20°C and the melting point of the copolymer + 140°C. Conventional methods, such as strand cutting, hot cutting, underwater cutting, and sheet cutting, can be used to cut the copolymer. The resulting pellets may be heated to remove volatile components (degassing treatment). The resulting pellets may also be treated by contacting them with hot water at 30 to 200°C, steam at 100 to 200°C, or hot air at 40 to 200°C.

[0052] Specific examples of the molded article of the present invention include nuts, bolts, joints, films, bottles, gaskets, wire coating materials, tubes, hoses, pipes, valves, sheets, seals, packing, tanks, rollers, containers, cocks, connectors, filter housings, filter cages, flow meters, pumps, wafer carriers, and wafer boxes.

[0053] The copolymer, the solid composition, or the molded article of the present invention can be used in the following applications: fluid transfer components for food manufacturing equipment, such as food packaging films, lining materials for fluid transfer lines used in food manufacturing processes, packings, sealing materials, and sheets; chemical liquid transfer components, such as chemical stoppers, packaging films, lining materials for fluid transfer lines used in chemical manufacturing processes, packings, sealing materials, and sheets; inner lining components for chemical liquid tanks and piping in chemical plants or semiconductor factories; fuel transfer components, such as O-rings, tubes, packings, valve core materials, hoses, and sealing materials used in automobile fuel systems and peripheral devices, and hoses and sealing materials used in automobile automatic transmissions; carburetor flange gaskets, shaft seals, valve stem seals, sealing materials, and hoses used in automobile engines and peripheral devices, as well as other automobile components, such as automobile brake hoses, air conditioner hoses, radiator hoses, and wire coating materials; semiconductor manufacturing equipment, such as O-rings, tubes, packings, valve core materials, hoses, sealing materials, rolls, gaskets, diaphragms, and fittings. steam piping components such as tubes and hoses for transporting waste liquid; high-temperature liquid transport components such as tubes and hoses for transporting high-temperature liquids; steam piping components such as tubes and hoses for steam piping; anti-corrosion tapes for piping such as tapes wrapped around piping on ship decks; various coating materials such as electric wire coating materials, optical fiber coating materials, and transparent surface coating materials and backing agents provided on the light-incident surface of photovoltaic elements in solar cells; sliding components such as diaphragms and various gaskets for diaphragm pumps; agricultural films, carrier films for fuel cells, and weather-resistant covers for various roofing materials and side walls; interior materials used in the construction field, and glass coating materials such as non-flammable fire-resistant safety glass; and lining materials such as laminated steel sheets used in home appliances.

[0054] In particular, the molded article of the present invention can be suitably used as piping components (e.g., piping, joints, gaskets, and packings), tubes, or films for transporting fluids. The molded article of the present invention can also be suitably used as a wire coating material. A specific example of use is a coated electric wire comprising a core wire and a coating layer formed around the core wire and made of the molded article of the present invention. A coated electric wire having a coating layer made of the molded article of the present invention has excellent electrical properties because the core wire is resistant to corrosion and there is little change in its outer diameter, and is therefore suitably used as a high-frequency transmission cable, a flat cable, a heat-resistant cable, or the like. Such a coated electric wire can be produced, for example, by melt-extrusion molding the present copolymer or the present composition onto a core wire to form a coating layer.

[0055] The molded article of the present invention can also be suitably used as a compressed member. The compressed member is a member used in a compressed and deformed state, and the size and shape of the compressed member are appropriately set depending on the application. The shape of the compressed member may be, for example, annular. The compressed member may have a shape such as a circle, an oval, or a rectangle with rounded corners in a plan view, and may have a through-hole in its center. The compressed member can be used as a piping member for transporting fluids. The compressed member can also be used as a member for constituting a nonaqueous electrolyte battery, and is particularly suitable as a member used in contact with the nonaqueous electrolyte in the nonaqueous electrolyte battery. The compressed member can also be suitably used as a sealing member such as a sealing gasket and a sealing packing, and as an insulating member such as an insulating gasket and an insulating packing. A sealing member is a member used to prevent the leakage of liquid or gas or the intrusion of liquid or gas from the outside. An insulating member is a member used for electrical insulation. The compressed member may be a member used for both sealing and insulating purposes.

[0056] The present invention will be described in detail below with reference to examples. Examples 1 to 14 are working examples, and Examples 15 to 21 are comparative examples. However, the present invention is not limited to these examples. Various measurement methods and evaluation methods are as follows.

[0057] [Proportion of Each Unit] The contents (mass%) of TFE units and PAVE units in each copolymer are １９ The molar ratio calculated by F-NMR analysis was converted to a mass ratio from the chemical structural formula of each unit. In each example, the composition of each non-fluorination-treated polymer and the fluorination-treated copolymer were the same. Specifically, in Example 1, the composition of Copolymer 1 (polymer after fluorination treatment) was the same as the composition of Polymer 1 without fluorination treatment.

[0058] [Number of Functional Groups] Molded bodies (pellets) of the solid compositions obtained in each example were molded by hot pressing at 330°C to produce films with a thickness of 0.30 to 0.35 mm. This film was scanned 40 times using a Fourier transform infrared spectrometer (FT-IR, "Spectrum One", manufactured by PerkinElmer) and analyzed to obtain an infrared absorption spectrum. Next, each of the pellets was subjected to a fluorination treatment described below for a long period of time, and base pellets that were completely fluorinated and had no specific functional groups were separately prepared, and base films were obtained in the same manner as above. A difference spectrum from the base spectrum of the base film was obtained. From the absorption peaks of the specific functional groups appearing in this difference spectrum, the number of carbon atoms of the copolymer in the sample was calculated according to the above formula (A). ６ The number of functional groups per molecule, N, was calculated.

[0059] [Melting Point] Using a molded product (pellet) of the solid composition obtained in each example, the melting point (°C) of the copolymer was determined from the endothermic peak observed when the copolymer was heated in an air atmosphere at a rate of 10°C / min up to 300°C using a differential scanning calorimeter (trade name "DSC7020", manufactured by Hitachi High-Tech Science Corporation).

[0060] [MFR] Using a molded product (pellet) of the solid composition obtained in each example, the mass (g) of the solid composition flowing out of an orifice having a diameter of 2 mm and a length of 8 mm in 10 minutes at a temperature of 372°C and a load of 5 kg was measured using a melt indexer (manufactured by Techno Seven Co., Ltd.) in accordance with ASTM D1238, and this was taken as the MFR (g / 10 min).

[0061] [Metal Element Content] The metal element content in the solid composition was determined by adding up the contents of 29 types of metal elements (Fe, Na, K, Li, Be, Mg, Al, Ca, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Mo, Ag, Cd, In, Sn, Cs, Ba, Pb, and Bi) measured by an absolute calibration curve method using an inductively coupled plasma mass spectrometer (ICP-MS 7500cs (product name), manufactured by Agilent Technologies) after the solid composition was placed in a platinum crucible and incinerated in a high-temperature electric heating furnace, followed by treatment with white sulfuric acid and dissolving the solid composition in dilute nitric acid. The metal element contents of the ultrapure water were determined by adding up the contents of the 29 metal elements measured by the absolute calibration curve method using an inductively coupled plasma mass spectrometer (ICP-MS 7500cs (product name), manufactured by Agilent Technologies) for the ultrapure water, in the same manner as in the above-mentioned measurement method.

[0062] [Evaluation Test] <Foamability> A molded product (pellets, 2 g) of the solid composition obtained in each example was placed in a watch glass and heated in an oven at 350°C for 60 minutes. After heating, holes and recesses present on the surface of the pellets as traces of foaming were visually confirmed. Next, the ratio of the total area of ​​the holes and recesses to the total surface area of ​​the pellet was calculated and used as the ratio of the area where foaming occurred. From the calculated ratio, foamability was evaluated based on the following evaluation criteria. (Evaluation criteria for heat resistance) "A": The ratio of the total area where foaming occurred to the total surface area is less than 50% "B": The ratio of the total area where foaming occurred to the total surface area is 50% or more

[0063] <Thermal Weight Loss Rate> A molded product (pellets, 5 g) of the solid composition obtained in each example was weighed and placed in a glass container (mass W1) and heated in an oven at 380°C for 60 minutes. The mass W2 of the solid composition after heating was measured, and the thermal weight loss rate ΔW (mass %) after heating was calculated using the following formula: ΔW = (W1 - W2) / W1 x 100 Evaluation was performed based on the calculated thermal weight loss rate ΔW according to the following evaluation criteria: (Evaluation criteria for heat resistance) "A": Thermal weight loss rate ΔW is less than 0.100 mass % "B": Thermal weight loss rate ΔW is 0.100 mass % or more

[0064] <Colorability (Yellowness Index)> Molded bodies (pellets) of the solid compositions obtained in each example were press-molded at 340°C using a heated press ("SA-301" manufactured by Tester Sangyo Co., Ltd.) to obtain films with a thickness of 200 μm. The YI (Yellow Index) values ​​of the obtained films with a thickness of 200 μm were measured using a color difference meter ("ZE-2000" manufactured by Nippon Denshoku Industries Co., Ltd.). From the measured YI values, the colorability (yellowness index) was evaluated based on the following evaluation criteria. A larger YI value indicates a higher yellowness index of the film. (Evaluation criteria for colorability) "A": YI value less than -1.50 "B": YI value of -1.50 or more

[0065] <Tensile Strength After Heat Aging Test> The molded body (pellet) of the solid composition obtained in each example was press-molded at 340 ° C. using a heated press ("SA-301" manufactured by Tester Sangyo Co., Ltd.) to obtain a 1 mm thick film. From the obtained 1 mm thick film, a dumbbell-shaped test piece specified in ASTM-D638 Type V was cut out and exposed to an ambient temperature of 275 ° C. for 500 hours. Thereafter, using a Strograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the distance between the gripping jigs was set to 35 mm, and the test piece was pulled at a pulling rate of 50 mm / min in an environment with a temperature range of 23 ± 2 ° C., to measure the tensile strength (unit: MPa). From the measured tensile strength values, the tensile strength after the heat aging test was evaluated based on the following evaluation criteria. (Evaluation criteria for tensile strength after heat aging test) "A": Tensile strength after heat aging test is more than 40.0 MPa "B": Tensile strength after heat aging test is 40.0 MPa or less

[0066] <Folding Endurance> A folding fatigue test was carried out according to the MIT method, which is known as a method for evaluating stress crack resistance, in accordance with ASTM D2176. First, a molded body (pellet) of the solid composition obtained in each example was press-molded at 340°C using a heated press ("SA-301" manufactured by Tester Sangyo Co., Ltd.) to obtain a film having a thickness of 0.23 mm. A rectangular test piece having a width of 12.5 mm and a length of 130 mm was cut out from the obtained film having a thickness of 0.23 mm. The obtained test piece was mounted on an MIT folding fatigue tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the test piece was bent under conditions of a load of 1.25 kg, a left and right bending angle of 135 degrees each, and a bending frequency of 175 times / min, and the number of times the test piece was bent until it broke (folding endurance number) was measured. From the measured folding endurance number, folding endurance was evaluated based on the following evaluation criteria. A higher number of folding endurance numbers indicates better folding endurance. (Evaluation criteria for folding endurance) "A": Endurance to folding times of 10,000 or more "B": Endurance to folding times of 1,000 or more but less than 10,000 "C": Endurance to folding times of less than 1,000

[0067] <Bending Strength> The molded body (pellets) of the solid composition obtained in each example was press-molded at 340°C using a heated press ("SA-301" manufactured by Tester Sangyo Co., Ltd.) to obtain a film having a thickness of 3.4 mm. A test piece having a width of 12.7 mm, a length of 80 mm, and a thickness of 3.2 mm was prepared from the obtained film having a thickness of 3.4 mm, and the bending strength was measured at 23°C by a method in accordance with ASTM D790. (Evaluation criteria for bending strength) "A": bending strength is 17 MPa or more "B": bending strength is less than 17 MPa

[0068] <Flexural Modulus> Molded bodies (pellets) of the solid compositions obtained in each example were press-molded at 340°C using a heated press ("SA-301" manufactured by Tester Sangyo Co., Ltd.) to obtain films with a thickness of 3.4 mm. Test pieces with a width of 12.7 mm, a length of 80 mm, and a thickness of 3.2 mm were prepared from the obtained films with a thickness of 3.4 mm, and the flexural modulus was measured at 23°C by a method in accordance with ASTM D790. (Evaluation criteria for flexural modulus) "A": Flexural modulus of 540 MPa or more "B": Flexural modulus of less than 540 MPa

[0069] [Example 1] A polymerization vessel equipped with a stirrer was degassed and then CF ３ CH ２ OCF ２ CF ２ H (AE-3000: product name, manufactured by AGC) 899 g, ultrapure water 271 g, CF ２ = CFO (CF ２ ) ３ 63.9 g of F(PPVE) and 22.8 g of methanol were charged into the polymerization tank. Next, the temperature inside the polymerization tank was raised to 50°C (polymerization temperature), 181 g of tetrafluoroethylene (TFE) was further charged, and the pressure inside the polymerization tank was increased to 1.28 MPa (gauge pressure). 2 mL of a 0.06 mass% AE-3000 solution of heptafluorobutyroyl peroxide was charged as a polymerization initiator solution, polymerization was initiated, and the above polymerization initiator solution was subsequently continuously added. Furthermore, TFE was continuously charged so that the pressure during polymerization was maintained equal to the pressure at the start of polymerization. 295 minutes after the start of polymerization, 39 mL of the polymerization initiator solution was added, and at the point when 160 g of TFE was charged, the polymerization tank was cooled, and the polymerization tank was purged to recover unreacted TFE. The ultrapure water used in the polymerization reaction had an electrical conductivity of 0.06 μS / cm at 25° C. Furthermore, as a result of measurement by the above-mentioned method using ICP-MS, the content of metal elements contained in the ultrapure water used in the polymerization reaction was 0.1 ppm by mass or less relative to the total mass of the ultrapure water.

[0070] The obtained slurry of polymer 1 was filtered through a filter to separate the polymerization medium, and then dried at 150° C. for 15 hours to obtain polymer 1. The composition of polymer 1 was TFE unit / PPVE unit=96.7 / 3.3 (mass %).

[0071] A co-rotating twin-screw extruder kneader equipped with a screw having two kneading sections was prepared. Polymer 1 was charged into the hopper of the feeder of the twin-screw extruder kneader, and the polymer 1 was kneaded while being sucked through the vent section by a vacuum pump under conditions of a cylinder temperature of 380°C and a screw rotation speed of 100 rpm. Strands discharged from the vent section were gradually cooled and cut with a pelletizer to produce cylindrical untreated pellets 1 having 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.

[0072] Next, the untreated pellets 1 were subjected to a fluorination treatment in the following manner. The untreated pellets 1 were placed in a special tray and placed in a box-type reaction oven, and the oven was then sealed. After evacuating the oven, F ２ The gas concentration was adjusted to 20% by volume. ２ F diluted with gas ２ / N ２ The mixed gas was introduced into the oven. The pressure inside the oven was atmospheric pressure (1 atm), and the temperature was 230°C. ２ / N ２ One hour after the introduction of the mixed gas started, the oven was evacuated and the F ２ / N ２ The mixed gas was introduced, and the reaction was carried out for 12 hours at 230° C. After the reaction was completed, heating was stopped and N 2 was introduced into the oven. ２ Gas is introduced into the oven. ２ / N ２ Mixed gas is sufficiently N ２ The atmosphere was replaced with gas, and a molded body (pellet) of solid composition 1 containing copolymer 1 was obtained.

[0073] [Example 2] A molded product (pellet) of solid composition 2 containing copolymer 2 of Example 2 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 66.4 g and 22.5 g, respectively, and the total amount of the polymerization initiator solution continuously charged was changed to 33 mL. The polymerization time was 350 minutes.

[0074] [Example 3] A molded product (pellet) of solid composition 3 containing copolymer 3 of Example 3 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 58.8 g and 22.5 g, respectively, and the total amount of the polymerization initiator solution continuously charged was changed to 32 mL. The polymerization time was 345 minutes.

[0075] [Example 4] A molded product (pellet) of solid composition 4 containing copolymer 4 of Example 4 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 69.0 g and 23.7 g, respectively, and the total amount of the polymerization initiator solution continuously charged was changed to 33 mL. The polymerization time was 390 minutes.

[0076] [Example 5] A molded product (pellet) of solid composition 5 containing copolymer 5 of Example 5 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 61.3 g and 24.6 g, respectively, and the total amount of the polymerization initiator solution continuously charged was changed to 32 mL. The polymerization time was 370 minutes.

[0077] [Example 6] A molded product (pellet) of solid composition 6 containing copolymer 6 of Example 6 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 58.8 g and 25.7 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 31 mL. The polymerization time was 380 minutes.

[0078] [Example 7] A molded product (pellet) of solid composition 7 containing copolymer 7 of Example 7 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 69.0 g and 24.5 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 36 mL. The polymerization time was 365 minutes.

[0079] [Example 8] A molded body (pellet) of solid composition 8 containing copolymer 8 of Example 8 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 63.9 g and 25.5 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 46 mL. The polymerization time was 275 minutes.

[0080] [Example 9] A molded product (pellet) of solid composition 9 containing copolymer 9 of Example 9 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 69.0 g and 25.3 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 36 mL. The polymerization time was 380 minutes.

[0081] [Example 10] A molded body (pellet) of solid composition 10 containing copolymer 10 of Example 10 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 58.8 g and 26.8 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 32 mL. The polymerization time was 390 minutes.

[0082] [Example 11] A molded body (pellet) of solid composition 11 containing copolymer 11 of Example 11 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 66.4 g and 25.9 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 37 mL. The polymerization time was 360 minutes.

[0083] [Example 12] A molded product (pellet) of solid composition 12 containing copolymer 12 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 58.8 g and 27.5 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 36 mL. The polymerization time was 350 minutes.

[0084] [Example 13] A molded product (pellet) of solid composition 13 containing copolymer 13 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 66.4 g and 26.6 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 41 mL. The polymerization time was 340 minutes.

[0085] [Example 14] A molded product (pellet) of solid composition 14 containing copolymer 14 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 70.6 g and 22.6 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 36 mL. The polymerization time was 345 minutes.

[0086] [Example 15] A molded product (pellet) of solid composition 15 containing copolymer 15 was obtained in the same manner as in Example 1, except that the amounts of PPVE and methanol initially charged into the polymerization vessel were changed to 82.1 g and 21.8 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 38 mL. The polymerization time was 370 minutes.

[0087] [Example 16] A molded body (pellet) of solid composition 16 containing copolymer 16 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 58.8 g and 28.6 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 37 mL. The polymerization time was 355 minutes.

[0088] [Example 17] Polymer 17 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 58.8 g and 27.5 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 37 mL. The polymerization time was 340 minutes. Subsequently, untreated pellets 17 were prepared from polymer 17 in the same manner as in Example 1, and the pellets were again subjected to F ２ / N ２ Untreated pellets 17 were subjected to a fluorination treatment in the same manner as in Example 1, except that the reaction time after the introduction of the mixed gas was changed to 0.5 hours, thereby obtaining a molded body (pellet) of solid composition 17 containing copolymer 17.

[0089] [Example 18] A molded product (pellet) of solid composition 18 containing copolymer 18 was obtained in the same manner as in Example 1, except that the amount of PPVE and the amount of methanol initially charged into the polymerization vessel were changed to 61.3 g and 19.4 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 25 mL. The polymerization time was 375 minutes.

[0090] [Example 19] A molded product (pellet) of solid composition 19 containing copolymer 19 was obtained in the same manner as in Example 1, except that the amounts of PPVE and methanol initially charged into the polymerization vessel were changed to 51.3 g and 24.3 g, respectively, and the amount of polymerization initiator solution continuously charged was changed to 25 mL. The polymerization time was 385 minutes.

[0091] [Example 20] A molded body (pellet) of solid composition 20 containing copolymer 20 was obtained in the same manner as in Example 1, except that the ultrapure water initially charged into the polymerization vessel was changed to water having an electrical conductivity of 2.36 μS / cm at 25°C, the amount of PPVE was changed to 61.3 g, the amount of methanol was changed to 24.6 g, and the amount of polymerization initiator solution continuously charged was changed to 25 mL. The polymerization time was 370 minutes.

[0092] [Example 21] Copolymer 21 was obtained in the same manner as in Example 5, except that the amount of PPVE was changed to 61.3 g, the amount of methanol to 24.6 g, and the amount of polymerization initiator solution continuously charged to 25 mL. The polymerization time was 372 minutes. After removing the solvent and ultrapure water from copolymer 21, the filtrate was immersed in ultrapure water (electrical conductivity at 25°C: 0.06 μS / cm) with stirring for 48 hours, and then the ultrapure water was removed again by filtration to obtain a copolymer. Subsequently, untreated pellets 21 of copolymer 21 were prepared in the same manner as in Example 1, and the untreated pellets 21 were subjected to a fluorination treatment to produce pellets 21. The pellets 21 were immersed in ultrapure water (electrical conductivity at 25°C: 0.06 μS / cm) and stirred for 48 hours.

[0093] The following table shows the composition of the copolymer of each example and the evaluation results. In the table, the "TEF unit (mass%)" column indicates the content (unit: mass%) of TFE units relative to all units contained in the copolymer. The "PPVE unit (mol%)" column indicates the content (unit: mass%) of PPVE units relative to all units contained in the copolymer. The "metal element (mass ppm)" column indicates the content (unit: mass%) of metal elements relative to the total mass of the solid composition measured by the above-mentioned method.

[0094]

[0095]

[0096] As shown in the above table, it was confirmed that the use of this solid composition made it possible to form molded articles that exhibited low coloration and foaming properties, a low rate of thermal weight loss, and excellent tensile strength, folding endurance, flexural strength, and flexural modulus after heat aging tests (Examples 1 to 14).

[0097] The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2024-092293 filed on June 6, 2024 are hereby incorporated by reference as the disclosure of the present invention.

Claims

1. A solid composition comprising a copolymer containing units based on tetrafluoroethylene and units based on perfluoro(alkyl vinyl ether), and a metal element, wherein the content of the units based on tetrafluoroethylene in the copolymer is 96.10 to 97.10 mass% based on all units contained in the copolymer, and the content of the units based on perfluoro(alkyl vinyl ether) is 2.90 to 3.90 mass% based on all units contained in the copolymer, and the -CF=CF ２ , -CF ２ H, -COF, -COOH, -COOCH ３ , -CONH ２ and -CH ２ The total number of OH functional groups is 10 ６ a melt flow rate of the solid composition measured at 372°C in accordance with ASTM D1238 of 11.0 to 22.0 g / 10 min; a melting point of the copolymer of 298.0°C or higher; and a content of the metal element of 0.0100 to 2.0000 ppm by mass relative to the total mass of the solid composition.

2. The solid composition of claim 1, wherein the perfluoro(alkyl vinyl ether) is perfluoro(propyl vinyl ether).

3. An extrusion molded product obtained by extruding the solid composition according to claim 1 or 2.

4. A blow-molded article obtained by blow-molding the solid composition according to claim 1 or 2.

5. A transfer molded article obtained by transfer molding the solid composition according to claim 1 or 2.

6. A press-molded product obtained by press-molding the solid composition according to claim 1 or 2.

7. An injection-molded article obtained by injection molding the solid composition according to claim 1 or 2.

8. A coated electric wire comprising a conductor and a coating layer disposed on the surface of the conductor and obtained by molding the solid composition according to claim 1 or 2.

9. A molded article obtained by molding the solid composition according to claim 1 or 2, wherein the molded article is a piping member, an electric wire coating material, a tube, a film or a compressed member.

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