Solid composition, method for producing solid composition, and molded body

Abstract

Provided is a solid composition which is excellent in heat resistance and bend resistance, wherein: a coating film formed from the solid composition by electrostatic coating is excellent in acid resistance; a coating film provided by the solid composition exhibits small thickness variation; and a coating film formed from the solid composition by rotational molding has a narrow thickness distribution.　This solid composition comprises a copolymer that has: a unit based on tetrafluoroethylene; a unit based on ethylene; and a unit based on at least one specific compound selected from the group consisting of a compound represented by formula (1): CZ2=CX(CF2)mY and a compound represented by formula (2): CF2=CF-O-(CF2)nF, wherein the total content of the unit based on tetrafluoroethylene and the unit based on ethylene is 80.00-99.50 mol% with respect to the total units of the copolymer, the content of the unit based on the specific compound is 0.50-4.00 mol% with respect to the total units of the copolymer, the metal elution amount calculated by test 1 is more than 5.0 μg / cm2 and 40.0 μg / cm2 or less, and the melt flow rate measured according to ASTM D3169 at a temperature of 297°C and a load of 49N is 2-50 g per 10 minutes.　Test 1: The solid composition is immersed in ultrapure water at 85°C for 7 days, and the amount of metal elements eluted into the ultrapure water is then measured.

Description

Solid composition, method for producing solid composition, and molded product

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

[0002] Ethylene / tetrafluoroethylene copolymer (hereinafter also referred to as "ETFE") is excellent in heat resistance, weather resistance, electrical insulation, non-stickiness, water and oil repellency, etc., and is characterized by high moldability and mechanical strength among fluororesins. Therefore, a variety of molded articles such as electric wire coverings, tubes, sheets, films, filaments, pump casings, joints, packings, linings, and coatings are produced by melt molding methods such as extrusion molding, blow molding, injection molding, and rotational molding. For example, Patent Document 1 discloses a method for recovering a fluorinated ether, including a step of producing a wet copolymer by suspension polymerization, solution polymerization, or bulk polymerization in the presence of a predetermined fluorinated ether, a step of heating the wet copolymer in a vessel to vaporize and discharge a vaporized substance containing the fluorinated ether, and a step of transferring the vaporized substance to a cooling means and cooling it.

[0003] Patent No. 5569660

[0004] When the solid composition that contains ETFE is used as the constituent material of molded body, it is required to have excellent performance in various aspects.For example, it can be mentioned that it has excellent heat resistance and folding endurance.In addition, when the solid composition is electrostatically coated and used as a coating film, it is required that the acid resistance of the coating film is excellent and the film thickness variation is small.In addition, when the solid composition is formed into a film by rotational molding, it is also required that the thickness distribution of the obtained film is small.

[0005] The present invention has been made in view of the above problems, and aims to provide a solid composition that has excellent heat resistance and folding resistance, and that produces a coating film that is excellent in acid resistance when electrostatically coated, with little variation in coating thickness, and with little thickness distribution when formed by rotational molding, as well as a method for producing the same. Another aim is to provide a molded product using the solid composition.

[0006] As a result of extensive research into the above-mentioned problems, the present inventors have found that a polymerizable composition containing a polymerizable compound containing a unit based on tetrafluoroethylene, a unit based on ethylene, and a unit based on at least one specific compound selected from the group consisting of a compound represented by formula (1) described later and a compound represented by formula (2) described later in a predetermined ratio can exhibit a metal elution amount of 5 to 40 μm / cm as calculated by test 1 described later. ２ and a melt flow rate (MFR) measured according to the requirements described below of 2 to 50 g / min., the solid composition satisfies all of the desired properties, and the present invention has been completed based on this finding.

[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 having units based on tetrafluoroethylene, units based on ethylene, and units based on at least one specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2) described below, wherein the total content of the units based on tetrafluoroethylene and the units based on ethylene is 80.00 to 99.50 mol % based on all units of the copolymer, the content of the units based on the specific compound is 0.50 to 4.00 mol % based on all units of the copolymer, and the amount of metal elution calculated by Test 1 is 5.0 μg / cm ２ Super 40.0μg / cm ２A solid composition having a melt flow rate of 2 to 50 g / 10 min, measured in accordance with ASTM D3169 at a temperature of 297°C and a load of 49 N. Test 1: The solid composition is immersed in ultrapure water at 85°C for 7 days, and the amount of metal element eluted into the ultrapure water is measured. [2] The solid composition according to [1], wherein the copolymer is a copolymer consisting only of units based on tetrafluoroethylene, units based on ethylene, and units based on at least one specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2). [3] The solid composition according to [1] or [2], wherein the specific compound is the compound represented by formula (1). [4] The solid composition according to any one of [1] to [3], wherein the content of units based on tetrafluoroethylene is 49 to 60 mol % of all units contained in the copolymer. [5] The solid composition according to any one of [1] to [4], wherein the content of the ethylene-based units is 38 to 49 mol% based on the total units contained in the copolymer. [6] The solid composition according to any one of [1] to [5], wherein the melting point of the copolymer is 210°C to 290°C. [7] A method for producing the solid composition according to any one of [1] to [6], comprising polymerizing, in a polymerization solvent, monomers containing tetrafluoroethylene, ethylene, and at least one specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2), and heating the resulting copolymer, the polymerization solvent, and water with stirring to granulate and recover the granulated product to obtain a solid composition. [8] The method for producing the solid composition according to [7], wherein the amount of the specific compound used is 0.10 to 2.80 parts by mass per 100 parts by mass of the polymerization solvent. [9] The method for producing the solid composition according to [7], wherein the water is ultrapure water.

[10] The method for producing the solid composition according to [7], wherein the electrical conductivity of the water is 1.00 to 7.00 μS / cm.

[11] A molded article obtained by molding the solid composition according to any one of [1] to [6].

[0008] According to the present invention, there is provided a solid composition having excellent heat resistance and folding resistance, excellent acid resistance of a coating film formed by electrostatic coating, small coating film thickness variation, and small thickness distribution of a film formed by rotational molding. Also, there is provided a molded article using the solid composition.

[0009] The meanings of terms used in the present invention are as follows. A numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits. In the numerical ranges described in this specification in stages, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in this specification, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the Examples. In this specification, each component may be a single substance corresponding to the component, or two or more substances may be used in combination. Here, when two or more substances are used in combination for each component, the content of that component refers to the total content of the substances used in combination, unless otherwise specified. In this specification, a combination of two or more preferred embodiments is a more preferred embodiment.

[0010] "Unit" is a general term for 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. "Unit based on a monomer" will also be simply referred to as "unit" below. The content (mass % or mol %) of each unit relative to the total units contained in a polymer is determined by analyzing the polymer by solid-state nuclear magnetic resonance spectroscopy (NMR), and usually the content of each unit calculated from the amount of each monomer added is approximately the same as the actual content of each unit. "TFE unit" is a unit based on tetrafluoroethylene (hereinafter also referred to as "TFE") of the copolymer, and "E unit" is a unit based on ethylene of the copolymer. "A unit" is a unit based on a specific compound described below.

[0011] [Solid Composition] The solid composition of the present invention (hereinafter also simply referred to as "solid composition") is a solid composition containing a copolymer (hereinafter also simply referred to as "copolymer") having TFE units, E units, and A units based on at least one specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2), wherein the total content of TFE units and E units is 80.00 to 99.50 mol % based on all units of the copolymer, the content of A units is 0.50 to 4.00 mol % based on all units of the copolymer, and the amount of metal elution calculated by Test 1 (hereinafter also simply referred to as "metal elution amount") is 5.0 μg / cm ２ Super 40.0μg / cm ２ The MFR (hereinafter also simply referred to as "MFR") measured in accordance with ASTM D3169 under conditions of a temperature of 297°C and a load of 49 N is 2 to 50 g / 10 min. Test 1: The solid composition is immersed in ultrapure water at 85°C for 7 days, and then the amount of metal elements eluted into the ultrapure water is measured.

[0012] Although the details of why the solid composition of the present invention exhibits the desired properties are unknown, it is believed that this is due to the appropriate control of the A unit content, metal elution amount, and MFR. Specifically, because the A unit content in the copolymer is greater than or equal to a predetermined amount, the solid composition exhibits appropriate flexibility and therefore excellent folding endurance. On the other hand, because the content of A units, which are susceptible to deterioration due to the action of acids, etc., is less than or equal to a predetermined amount, it is presumed that the acid resistance of the coating film (hereinafter also simply referred to as "coating film") formed by electrostatically coating the solid composition is also excellent. Furthermore, because the metal elution amount is greater than or equal to a predetermined value, the metal components can interact with the copolymer and act as crosslinking points, and because it is less than or equal to a predetermined value, the occurrence of defects due to the metal components is suppressed. As a result, it is presumed that the performance does not deteriorate even after heat aging tests, resulting in excellent heat resistance. Furthermore, because the MFR is less than or equal to a predetermined value, it is easy to apply the coating uniformly, i.e., the coating film thickness variation is reduced. On the other hand, it is presumed that the intermolecular interactions function properly because the MFR is equal to or greater than a predetermined value, and the thickness distribution of the film formed by rotational molding (hereinafter also simply referred to as "rotational molded body") is small.

[0013] <Copolymer> The solid composition contains a copolymer having TFE units, E units, and A units. The A units are units based on a specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2).

[0014] CZ ２ =CX(CF ２ ) ｍ Y Formula (1) CF ２ =CF-O-(CF ２ ) ｎ F Formula (2) In formula (1), X, Y, and Z each independently represent a hydrogen atom or a fluorine atom, and m represents an integer of 2 to 6. Two Zs may be the same or different. In formula (2), n represents an integer of 1 to 6.

[0015] In the compound represented by formula (1), X and the two Zs are preferably hydrogen atoms from the viewpoint of polymerizability. Y is preferably a fluorine atom from the viewpoint of heat resistance. m is an integer of 2 to 6, preferably an integer of 3 to 6, and more preferably 3 or 4.

[0016] Examples of the compound represented by formula (1) include CH ２ =CH(CF ２ ) ２ F, CH ２ =CH(CF ２ ) ４ F (hereinafter also referred to as "PFBE"), CH ２ =CH(CF ２ ) ６ F, CH ２ =CF(CF ２ ) ３ F and CH ２ =CF(CF ２ ) ４ F, PFBE, CH ２ =CH(CF ２ ) ６ F or CH ２ =CF(CF ２ ) ３ F is preferred, and PFBE is more preferred.

[0017] Specific examples of the compound represented by formula (2) include CF ２=CF-O-(CF ２ ) F, CF ２ =CF-O-(CF ２ ) ２ F, CF ２ =CF-O-(CF ２ ) ３ F, CF ２ =CF-O-(CF ２ ) ４ F, CF ２ =CF-O-(CF ２ ) ５ F and CF ２ =CF-O-(CF ２ ) ６ Among them, CF corresponding to the compound where n is 3 ２ =CF-O-(CF ２ ) ３ F is preferred.

[0018] The copolymer may contain, as A units, either units based on a compound represented by formula (1) (hereinafter also referred to as "A1 units") or units based on a compound represented by formula (2) (hereinafter also referred to as "A2 units"), or may contain both A1 units and A2 units. When the copolymer contains both A1 units and A2 units, the "content of A units" means the sum of the content of A1 units and the content of A2 units.

[0019] As the copolymer, a copolymer containing TFE units, E units, and A1 units, or a copolymer containing TFE units, E units, and A2 units is preferred, and a copolymer containing E units, TFE units, and A1 units is more preferred from the viewpoint of better folding endurance.

[0020] The total content of TFE units and E units is 80.00 to 99.50 mol% based on the total units of the copolymer. From the viewpoint of folding endurance and acid resistance of the coating film, it is preferably 80.00 to 99.00 mol%, more preferably 85.00 to 99.00 mol%, more preferably 95.0 to 99.50 mol%, even more preferably 96.70 to 98.35 mol%, and particularly preferably 97.50 to 97.80 mol%. The content of TFE units is preferably 45.00 to 67.00 mol%, more preferably 48.00 to 64.90 mol%, even more preferably 49.00 to 64.50 mol%, and particularly preferably 49.00 to 60.00 mol%, based on the total units contained in the copolymer. If it is equal to or greater than the lower limit, the heat resistance of the molded article obtained by molding the solid composition is superior, and if it is equal to or less than the upper limit, the mechanical properties of the molded article are superior. The content of E units is preferably 30.0 to 55.0 mol%, more preferably 35.00 to 51.90 mol%, even more preferably 35.0 to 49.50 mol%, and particularly preferably 38.00 to 49.00 mol%, based on all units contained in the copolymer. A content above the lower limit provides superior mechanical properties for a molded article obtained by molding the solid composition, while a content below the upper limit provides superior heat resistance for the molded article. In particular, from the viewpoint of excellent acid resistance of the coating film, the content of E units is preferably 44.00 mol% or more, more preferably 45.00 mol% or more, based on all units contained in the copolymer. In particular, from the viewpoint of excellent folding endurance, the content of E units is preferably 51.90 mol% or less, more preferably 45.80 mol% or less, and particularly preferably 44.50 mol% or less, based on all units contained in the copolymer.

[0021] The content of A units is 0.50 to 4.00 mol% based on all units contained in the copolymer, and from the viewpoints of folding endurance and acid resistance of the coating film, it is preferably 0.60 to 3.90 mol%, more preferably 0.80 to 3.80 mol%, even more preferably 1.65 to 3.30 mol%, and particularly preferably 2.20 to 2.50 mol%.

[0022] The copolymer may contain units based on a monomer other than TFE, ethylene, and the specific compound. Specific examples of the other monomer include fluoroolefins (e.g., vinyl fluoride, vinylidene fluoride, trifluoroethylene, hexafluoroisobutylene, etc., excluding the specific compound), CF ２ =CFORf １ SO ２ Y １ (However, Rf １ is a perfluoroalkylene group having 1 to 10 carbon atoms which may contain an oxygen atom between the carbon atoms, and Y １ is a halogen atom or a hydroxyl group.), CF ２ =CFORf ２ CO ２ Y ２ (However, Rf ２ is a perfluoroalkylene group having 1 to 10 carbon atoms which may contain an oxygen atom between the carbon atoms, and Y ２ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.), CF ２ =CF(CF ２ ) pOCF=CF ２ (where p is 1 or 2), fluorine-containing monomers having a ring structure (for example, perfluoro(2,2-dimethyl-1,3-dioxole), 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxole, perfluoro(2-methylene-4-methyl-1,3-dioxolane)), itaconic acid, itaconic anhydride, citraconic acid, and citraconic anhydride. Among these, itaconic acid, itaconic anhydride, citraconic acid, and citraconic anhydride are preferred, and itaconic anhydride is more preferred.

[0023] When the copolymer contains units based on other monomers, the content of the units based on other monomers is preferably 0.01 to 2.00 mol %, more preferably 0.10 to 1.00 mol %, based on all units contained in the copolymer.

[0024] The copolymer is preferably one which is composed of TFE units, E units and A units and does not contain units based on other monomers, and more preferably one which is composed of TFE units, E units and A1 units and does not contain A2 units and units based on other monomers.

[0025] The content of the copolymer is preferably 50% by mass or more and less than 100% by mass, more preferably 70% by mass or more and less than 100% by mass, and particularly preferably 90% by mass or more and less than 100% by mass, based on the total mass of the solid composition.

[0026] <Metal Element> The solid composition may contain a metal element. The content of the metal element is preferably 0.02 to 1.0 ppm by mass, more preferably 0.05 to 0.9 ppm by mass, and even more preferably 0.1 to 0.8 ppm by mass, relative to the total mass of the solid composition. The content of the metal element in the solid composition can be measured, for example, using an inductively coupled plasma mass spectrometer (ICP-MS) according to the following procedure. The content of metal elements in the solid composition is 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 is 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.

[0027] <Other Components> The solid composition may contain other components in addition to those described above. Specific examples of other components include resins other than the copolymer, heat stabilizers, antioxidants, colorants, UV absorbers, fillers, crosslinking agents, crosslinking aids, and organic peroxides. When the 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 particularly preferably 0.000001 to 50 parts by mass, relative to 100 parts by mass of the copolymer in the solid composition.

[0028] <Properties of solid composition> (Amount of eluted metal) The amount of eluted metal of the solid composition calculated by Test 1 was 5.0 μg / cm ２ Super 40.0μg / cm ２ From the viewpoint of heat resistance, it is 10 to 40 μg / cm ２is preferred, and 10 to 14 μg / cm ２ More preferably, 11.5 to 13.8 / cm ２ Test 1: After immersing the solid composition in ultrapure water at 85°C for 7 days, the amount of metal elements eluted into the ultrapure water is measured. More specifically, a sample of the solid composition is immersed in ultrapure water at 85°C for 7 days, and the total content of metal elements contained in the ultrapure water is measured, and the amount of metal elements eluted into the ultrapure water is measured. ２ Metal elution amount per unit area (μg / cm ２ ) can be calculated. The total content of the metal elements is the sum of 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). The content of each metal element contained in ultrapure water can be measured using an inductively coupled plasma mass spectrometer (ICP-MS 7900 (product name), manufactured by Agilent Technologies). More detailed methods for measuring the amount of eluted metal are as described in the Examples below. In calculating the amount of eluted metal, the surface area of ​​the solid composition can be calculated by a known method. Specific examples include a method of calculating from the dimensions of the molded body used in the measurement, a method of calculating from the average particle diameter calculated from microscopic observation of the particulate solid composition, and a method of calculating from the specific surface area determined by gas adsorption etc. Specific examples of methods for controlling the amount of metal elution from the solid composition include adjusting the electrical conductivity of the water used in the granulation step described below, adjusting the time for removing the organic solvent, and adjusting the amount of raw material used.

[0029] (MFR) The solid composition has an MFR of 2 to 50 g / 10 min, measured in accordance with ASTM D3169 under conditions of a temperature of 297°C and a load of 49 N. The MFR is preferably 3 to 45 g / 10 min, more preferably 3 to 40 g / 10 min, and even more preferably 13 to 30 g / 10 min, in order to facilitate reducing the variation in film thickness of the coating film and the thickness distribution of the rotationally molded product. More specifically, the MFR is obtained by measuring the mass of the solid composition flowing out of an orifice having a diameter of 2 mm and a length of 8 mm in 10 minutes under conditions of a temperature of 297°C and a load of 49 N in accordance with ASTM D3169.

[0030] (Melting Point) The melting point of the solid composition is preferably 210°C or higher, more preferably 215°C or higher, even more preferably 220°C or higher, and particularly preferably 225°C or higher, from the viewpoint of superior mechanical strength when used at high temperatures. The upper limit of the melting point of the solid composition is preferably 290°C or lower, more preferably 280°C or lower, and even more preferably 270°C or lower, from the viewpoint of superior moldability. The melting point of the solid composition is preferably 210°C or higher and 290°C or lower, more preferably 215°C or higher and 280°C or lower, even more preferably 225°C or higher and 270°C or lower, from the viewpoint of a well-balanced superiority in mechanical strength and moldability when used at high temperatures. The melting point of the solid composition is the temperature corresponding to an endothermic peak detected when the solid composition is heated at a rate of 10°C / min in an air atmosphere using a differential scanning calorimeter.

[0031] <Method for Producing Solid Composition> Examples of methods for producing the solid composition include a method of polymerizing the copolymer and recovering the solid, and a method of melt-kneading the copolymer or the solid, and other components as necessary, by a known method.

[0032] (Production of copolymer) Copolymer can be produced by known method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, etc., using TFE, ethylene, specific compound, and if necessary, other monomers, and among them, preferably produced by solution polymerization using polymerization solvent.In the production of this copolymer, in addition to the above-mentioned monomers, polymerization initiator, polymerization medium, chain transfer agent, etc. can be used.

[0033] The amount of the monomer used can be appropriately selected depending on the composition of the target solid composition, etc. In particular, the amount of the specific compound used is preferably 0.10 to 2.80 parts by mass, more preferably 0.10 to 2.51 parts by mass, per 100 parts by mass of the polymerization solvent.

[0034] 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 particularly preferably a radical polymerization initiator having a temperature of 20 to 90°C. Specific examples of the polymerization initiator include various polymerization initiators exemplified in WO 2013 / 015202. The polymerization initiator may be used alone or in combination of two or more types.

[0035] The polymerization medium may be a perfluorocarbon, a hydrofluorocarbon, a hydrofluoroether, or the like. Specific examples of the polymerization medium include those exemplified in International Publication No. 2013 / 015202. The polymerization medium may be used alone or in combination of two or more. The amount of the polymerization medium used is preferably 5 times or more, more preferably 7 times or more, by mass ratio relative to the amount of the monomer used. The amount is preferably 20 times or less, more preferably 17 times or less.

[0036] The chain transfer agent may be selected from the group consisting of alcohols such as methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3,3-hexafluoroisopropanol, and 2,2,3,3,3-pentafluoropropanol, hydrocarbons such as n-pentane, n-hexane, and cyclohexane, and CF ２ H ２Preferred 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, and at least one selected from the group consisting of alcohols and hydrocarbons is more preferred, with alcohols being particularly preferred, in terms of a higher chain transfer constant and high stability of the terminal groups of the copolymer. Among alcohols, methanol or ethanol is particularly preferred. Among these, methanol is particularly preferred in terms of reactivity and ease of availability. Two or more chain transfer agents may be used. The total amount of the specific compound and the chain transfer agent used is preferably 0.1 to 5.0 parts by mass, more preferably 0.2 to 4.0 parts by mass, and even more preferably 0.3 to 3.0 parts by mass, per 100 parts by mass of the polymerization solvent.

[0037] From the viewpoint of heat resistance, the polymerization temperature is preferably 15 to 60°C, more preferably 20 to 58°C, and particularly preferably 25 to 55°C. If the polymerization temperature is 15°C or higher, the polymerizability is excellent. 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, particularly preferably 0.9 to 2.5 MPa. The polymerization time is preferably 1 to 12 hours.

[0038] (Granulation) In the method for producing a solid composition, it is preferable to carry out granulation to produce a granulated product containing the copolymer by heating a mixture containing the obtained copolymer, polymerization solvent, and water while stirring. In granulation, first, a mixture containing the copolymer, polymerization solvent, and water is prepared. The mixture can be prepared, for example, by mixing a slurry containing the copolymer and polymerization solvent with water. To prepare the mixture, the slurry after copolymer production may be used as is, or a concentrated slurry or a slurry obtained by diluting the slurry with a dilution solvent may be used. The dilution solvent may be the same as or different from the solvent used as the polymerization solvent, but is preferably the same. The amount of water used in granulation may be 20 to 500% by volume, more preferably 50 to 300% by volume, based on the total amount of the copolymer and polymerization solvent.

[0039] The water is preferably ultrapure water. From the viewpoint of adjusting the amount of metal elution, the conductivity of the water is preferably 1.00 to 20.00 μS / cm, more preferably 1.00 to 15.00 μS / cm, even more preferably 1.00 to 13.00 μS / cm, and particularly preferably 1.00 to 7.00 μS / cm. When the conductivity of the water satisfies the above range, the amount of metal components incorporated into the copolymer particles in the granulation step can be adjusted, making it easier to obtain a solid composition with a desired amount of metal elution. The conductivity is a value at 23°C. The conductivity of the water can be measured using an electrode-type conductivity electrode. The conductivity of the water can be adjusted by passing the water through a reverse osmosis membrane or an ion exchange resin.

[0040] The metal content of the water is preferably 1 to 500 μg / L, more preferably 50 to 450 μg / L, and even more preferably 50 to 400 μg / L. The metal elements are not particularly limited as long as they can be measured by inductively coupled plasma mass spectrometry (ICP-MS), as described below, and examples include 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). It is preferable that the total content of the 29 metal elements falls within the preferred range.

[0041] The mixture may be prepared by adding water to the polymerization tank containing the slurry after the production of the copolymer, or by transferring the slurry to a container (granulation tank) separate from the polymerization tank and mixing the slurry with water. It is preferable to transfer the slurry containing the copolymer and polymerization solvent from the polymerization tank to a granulation tank previously charged with water and mix them. The granulation tank may be a sealable container equipped with a stirring blade for stirring the contents, a heating means for heating the container or the contents, and a discharge means for discharging the separated gas. Commonly used stirring blades such as turbine blades and anchor blades can be used as the stirring blade. Heating means include, for example, a jacket, a hot water bath, an oil bath, and steam heating.

[0042] During the granulation, it is preferable to vaporize and remove unreacted monomers and polymerization solvent from the copolymer by heating. From the viewpoint of adjusting the amount of metal elution, the time for removing the polymerization solvent is preferably 0.2 to 20 hours, more preferably 0.6 to 20 hours, even more preferably 1 to 20 hours, even more preferably 2 to 12 hours, and particularly preferably 2 to 8 hours. By controlling the time for removing the polymerization solvent, it is possible to adjust the amount of metal components derived from the water, granulation tank, stirring blades, etc., mixed into the copolymer particles, making it easier to obtain a solid composition with the desired amount of metal elution. The time for removing the polymerization solvent is intended to be the time from the start of heating until the point at which emission of volatile solvent is no longer confirmed. The heating temperature of the mixture during granulation is preferably in the range of 25 to 110°C, more preferably 30 to 90°C. The pressure inside the vessel during granulation is preferably 0.01 to 0.8 MPa, more preferably 0.01 to 0.7 MPa, and even more preferably 0.01 to 0.6 MPa. The pressures described herein are gauge pressures based on atmospheric pressure. The rate at which gas is discharged from the vessel during granulation is preferably 0.01 to 0.50 kg / L / h, more preferably 0.01 to 0.40 kg / L / h, and even more preferably 0.01 to 0.30 kg / L / h. The gas discharge rate is determined by the volume of the vessel used for granulation and the mass of gas discharged per hour. The granulation time may be, for example, 1 to 24 hours, preferably 1 to 15 hours. Granulation can be terminated, for example, when a period of time has passed during which the volume of the mixture contained in the granulation vessel does not decrease. When it is confirmed that the volume of the mixture in the granulation vessel has remained constant for a predetermined period of time, it can be assumed that most of the components, such as the solvent, discharged from the granulation vessel during the granulation have been discharged.

[0043] The granules obtained by the above granulation may be collected from the container and then dried, if necessary. Preferably, the collected granules are dried to obtain a solid composition. Specific examples of drying include transferring the collected granules to a dryer and heating them. By drying, substances such as water and solvents inside the granules can be further vaporized and removed.

[0044] Examples of the dryer used for drying include a batch type rotary dryer, an indirect heating dryer, a vacuum dryer, and a hot air dryer.

[0045] The drying temperature is preferably in the range of 60 to 250° C., more preferably in the range of 100 to 160° C. The drying time is preferably in the range of 1 to 48 hours, more preferably in the range of 1 to 24 hours.

[0046] The solid composition obtained by the above drying or granulation may be melted and extruded using an extruder to form a solid composition in other forms such as pellets or threads.

[0047] When the solid composition contains components other than the copolymer and the metal, the solid composition obtained by the drying or granulation or the powder obtained by pulverizing the solid composition may be melt-kneaded with the other components by a known method. The solid composition can be pulverized using a known pulverizer such as a rotor mill, a hammer mill, a turbo mill, or a jet mill.

[0048] [Molded Article] The molded article of the present invention can be obtained by molding the solid composition described above. Because the molded article of the present invention contains the copolymer described above, it has excellent heat resistance and folding resistance, the acid resistance of the coating film formed by electrostatic coating is excellent, the coating film has small thickness variation, and the thickness distribution of the film formed by rotational molding is also small. Furthermore, because the molded article of the present invention contains a predetermined amount of metal components as described above, it has excellent heat resistance. Specific molding methods include injection molding, extrusion molding, blow molding, press molding, rotational molding, and electrostatic coating. That is, the molded article of the present invention includes injection molded articles, extrusion molded articles, blow molded articles, press molded articles, rotational molded articles, and coating films formed by electrostatic coating. The molded article is preferably molded by press molding. Injection molding is also preferred because it can produce injection molded articles with beautiful appearance without corroding the mold used for molding. Rotational molding or electrostatic coating is also preferred because it can form a uniform coating film.

[0049] Specific examples of the molded article of the present invention include nuts, bolts, joints, films, bottles, gaskets, wire coatings, tubes, hoses, pipes, valves, sheets, seals, packing, tanks, rollers, containers, cocks, connectors, filter housings, filter cages, flow meters, pumps, wafer carriers, and wafer boxes.

[0050] The solid composition and 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, sealing materials, and sheets for fluid transfer lines used in food manufacturing processes; chemical liquid transfer components, such as chemical stoppers, packaging films, lining materials, packings, sealing materials, and sheets for fluid transfer lines used in chemical manufacturing processes; 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 automotive fuel systems and peripheral devices, and hoses and sealing materials used in automotive automatic transmissions; carburetor flange gaskets, shaft seals, valve stem seals, sealing materials, and hoses used in automotive engines and peripheral devices, as well as other automotive components, such as automotive brake hoses, air conditioner hoses, radiator hoses, and wire coating materials; chemical liquid transfer components for semiconductor manufacturing equipment, such as O-rings, tubes, packings, valve core materials, hoses, sealing materials, rolls, gaskets, diaphragms, and fittings; coating and ink components such as paint rolls, hoses, tubes, and ink containers for coating equipment; food and beverage transport components such as tubes, hoses, belts, packing, and joints, such as food and beverage tubes or food and beverage hoses, food packaging materials, and glass cooking equipment; waste liquid transport 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, etc.; various coating materials such as electric wire coating materials, optical fiber coating materials, and transparent surface coating materials and backing agents applied to the light-incident surface of photovoltaic elements in solar cells; sliding components such as diaphragms and various packings for diaphragm pumps; agricultural films, carrier films for fuel cells, and weather-resistant covers for various roofing materials and side walls, etc.; interior materials used in the construction field, and glass coating materials such as non-flammable fire-resistant safety glass; lining materials such as laminated steel sheets used in home appliances, etc.In particular, the molded article of the present invention is particularly suitable for use as a chemical liquid transport member and a coating material for semiconductor devices.

[0051] The present invention will be described in detail below with reference to examples. Examples 1 to 14 are working examples, and Examples 15 to 20 are comparative examples. However, the present invention is not limited to these examples. Various measurement methods and evaluation methods are as follows.

[0052] [Measurement] <Proportion of each unit> The content (mol %) of each unit in the copolymer is １９ The content of E units in the copolymer was calculated by F-NMR measurement. １ H and １３ Calculated by C-NMR measurement.

[0053] <Conductivity> The conductivity of the water was measured using an electrode-type conductivity electrode at 23°C.

[0054] <Metal Elution Amount> The metal elution amount was determined as the total amount of elution of 29 major metals (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) by the following procedure. The solid composition obtained in each example was melted and extruded using an extruder to form pellets. 30 g of this sample and the PFA container to be used were pre-cleaned in accordance with SEMI F40. 30 g of the pre-cleaned sample was placed in a pre-cleaned PFA container, and 100 mL of ultrapure water was poured into the container to completely immerse it. The container was then sealed and subjected to elution at 85°C ± 3°C for 7 days. Thereafter, the concentration of each of the 29 metal elements in the ultrapure water was measured using an inductively coupled plasma mass spectrometer (ICP-MS 7900 (product name), manufactured by Agilent Technologies), and the total content of the metal elements was determined. The total content was divided by the surface area of ​​the solid composition sample to determine the amount of metal elution (μg / cm ２) was determined. The surface area of ​​the solid composition sample was calculated from the dimensions of the pellet. The content of metal elements in the ultrapure water used in the above measurement was below the measurement limit. The pre-cleaning was performed using the following procedure. The PFA container was washed about five times with ultrapure water, and then an aqueous nitric acid solution diluted with water at a volume 20 times that of the nitric acid was poured into one-fifth of the container, shaken, and the contents were discarded, followed by washing with ultrapure water about 10 times. 30 g of the sample was placed in the pre-cleaned PFA container, 100 mL of 3.6% hydrochloric acid was added, and the sample was immersed at room temperature for 1 hour, after which the hydrochloric acid was drained and the sample was washed by pouring ultrapure water over it about 10 times.

[0055] <MFR> Using a melt indexer (manufactured by Techno Seven Co., Ltd.), 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 was measured under conditions of a temperature of 297°C and a load of 49 N in accordance with ASTM D3159, and this was taken as the MFR (g / 10 min).

[0056] <Melting Point> The melting point (°C) of the solid composition was determined from the endothermic peak observed when the copolymer was heated to 300°C at a rate of 10°C / min in an air atmosphere using a differential scanning calorimeter (trade name "DSC7020", manufactured by Hitachi High-Tech Science Corporation).

[0057] [Evaluation Test] <Powder Production Method> Using the solid compositions obtained in each example, a resin powder was obtained according to the procedure described in paragraph

[0123] of International Publication No. 2016 / 017801. The particle size distribution D50 of the obtained resin powder was 28.08 μm. The loosely packed bulk density was 0.61 g / mL, and the tightly packed bulk density was 0.76 g / mL.

[0058] <Film Forming> The resin powder obtained by the above procedure was press-molded at a temperature within the range of the melting point of the solid composition + 50°C ± 20°C (for example, 280°C to 320°C when the melting point of the copolymer is 250°C) to obtain films with thicknesses of 200 μm, 1 mm, and 0.23 mm. The press-molding was carried out using a heated press ("SA-301" manufactured by Tester Sangyo Co., Ltd.).

[0059] <Yellowness Index> The YI (Yellow Index) value of a 200 μm thick film was measured using a color difference meter (ZE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.). The yellowness index of each film was evaluated based on the measured YI value according to the following evaluation criteria. A larger YI value indicates a higher yellowness index of the film, and a smaller yellowness index is preferred.

[0060] (Yellowness Index Evaluation Criteria) A: YI value less than 6 B: YI value 6 or more

[0061] <Heat Resistance> A dumbbell-shaped test piece defined in JIS K6301 No. 3 was cut out from the obtained film having a thickness of 1 mm. The obtained test piece was pulled using a Strograph (manufactured by Toyo Seiki Seisaku-Sho, Ltd.) under conditions of a gauge length of 20 mm and a pulling speed of 200 mm / min in a constant temperature and humidity environment controlled at a temperature of 23±2°C and a humidity of 50%±10%, to measure the tensile elongation (unit: %) before the heat aging test.

[0062] The above test pieces were placed in a gear oven (forced circulation air heating aging tester) (manufactured by Toyo Seiki Seisakusho, Ltd.) and subjected to a heat exposure treatment. The heat exposure treatment was performed at a temperature of 250°C, and the heat treatment was performed for 48 hours after placement. The heat-treated test pieces were subjected to a tensile test according to the above method, and the tensile elongation (unit: %) after the heat aging test was measured. From the obtained results, the rate of change in tensile elongation before and after the heat aging test (unit: %, tensile elongation after heat aging test / tensile elongation before heat aging test × 100) was calculated. From the calculated rate of change, the heat resistance of each solid composition was evaluated based on the following evaluation criteria. A higher retention rate indicates better heat resistance.

[0063] (Evaluation criteria for heat resistance) A: The rate of change in tensile elongation before and after the heat aging test is 40% or more. B: The rate of change in tensile elongation before and after the heat aging test is less than 40%.

[0064] <Acid resistance of coating film> A SUS304 stainless steel plate measuring 50 mm in length, 150 mm in width, and 2 mm in thickness was baked at 400°C for 1 hour, and then its surface was sandblasted using alumina particles ("White Fused Alumina 50A (trade name)" manufactured by Pacific Random Co., Ltd.), and the blasted powder was removed with an air gun to obtain a substrate (1). The surface of the substrate (1) was electrostatically coated with a resin powder of the copolymer obtained in each example, and the substrate was placed in an oven and baked at 275°C for 15 minutes. The coating and baking steps were each performed four times, yielding a coated article in which a coating film layer made of powder and having a thickness of approximately 250 µm was formed on the substrate (1).

[0065] The resulting coated article (50 mm long, 150 mm wide) was used as a test piece to evaluate the adhesion between the substrate and the coating layer of the coated article using the following method. The coating layer was peeled from one lateral end of the test piece. The lateral length of the peeled portion of the coating layer was 10 mm. When peeling the coating layer, a cutter knife was used to make the peeling easier. The coating layer at the peeled portion from the substrate was fixed to the chuck of a tensile tester and pulled at a tensile speed of 50 mm / min, performing a 90-degree peel test. Peeling was performed from the end of the test piece to a position 50 mm wide. The above measurement was performed three times, and the maximum load at 90-degree peeling was determined for each measurement. The average value was used as the peel strength (unit: N / cm) before immersion in hydrochloric acid. The higher the peel strength, the better the adhesion. Furthermore, the coated article was immersed in 35% hydrochloric acid at room temperature for 24 hours, and then the above-mentioned 90-degree peel test was performed to determine the peel strength after immersion in hydrochloric acid. The measurement after immersion in hydrochloric acid was also performed three times, and the maximum load at 90-degree peeling in each measurement was determined, and the average value was taken as the peel strength after immersion in hydrochloric acid (unit: N / cm). From the obtained results, the retention rate of peel strength before and after immersion in hydrochloric acid (unit: %, peel strength after immersion in hydrochloric acid / peel strength before immersion in hydrochloric acid × 100) was calculated. From the calculated retention rate, the acid resistance of the coating film was evaluated based on the following evaluation criteria. A higher retention rate indicates a higher acid resistance of the coating film and lower chemical permeability.

[0066] (Evaluation Criteria for Acid Resistance) A: Peel strength retention rate before and after immersion in hydrochloric acid is 23% or more. B: Peel strength retention rate before and after immersion in hydrochloric acid is less than 23%.

[0067] <Folding Endurance> A folding fatigue test was carried out according to the MIT testing machine method, which is known as a method for evaluating stress crack resistance, in accordance with ASTM D2176. First, a rectangular test piece having a width of 12.5 mm and a length of 130 mm was cut out from the obtained 0.23 mm film. 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) was measured. The folding endurance of each film was evaluated based on the measured folding endurance number according to the following evaluation criteria. A higher number of folding endurance numbers indicates better folding endurance.

[0068] (Evaluation criteria for folding endurance) A: Number of folding times 40,000 or more B: Number of folding times less than 40,000

[0069] <Coating Thickness Variation> A 50 mm long, 150 mm wide, and 2 mm thick SUS304 stainless steel plate was baked at 400°C for 1 hour, and then its surface was sandblasted with alumina particles ("White Fused Alumina 50A (product name)" manufactured by Pacific Random Co., Ltd.). The blasted powder was removed with an air gun to obtain substrate (1). The surface of substrate (1) was electrostatically coated with a resin powder of the solid composition obtained in each example, and the substrate was placed in an oven and baked at 275°C for 15 minutes. The coating and baking processes were each performed four times to obtain a coated article in which a coating layer made of powder with a thickness of approximately 250 μm was formed on substrate (1). The coating thickness of the SUS304 stainless steel plate was measured at 30 mm (A), 60 mm (B), 90 mm (C), and 120 mm (D) from one end, and the coating thickness variation was evaluated based on the standard deviation of portions A to D according to the following evaluation criteria. The smaller the standard deviation, the smaller the variation in the coating thickness.

[0070] (Variation in coating film thickness) A: Standard deviation is less than 20.0 μm B: Standard deviation is 20.0 μm or more

[0071] <Thickness Distribution of Rotational Molded Articles> The thickness distribution of the film formed by rotational molding was evaluated by a lining test. The lining was performed using a rock-and-roll method. Resin powder of the solid composition obtained in each example was placed in a steel pipe with an outer diameter of 20 mm, and lining was performed by direct flame heating. The thickness of the resulting lining layer was measured at 1 cm intervals on the circumference of areas where surface irregularities were visually observed, and the difference between the minimum and maximum thicknesses was calculated. Furthermore, if no visual irregularities were observed, the thickness of any area on the circumference was measured at 1 cm intervals, and the difference between the minimum and maximum thicknesses was calculated. The thickness distribution of the rotational molded article was evaluated from the obtained difference based on the following evaluation criteria. A smaller difference between the maximum and minimum thicknesses of the rotational molded article indicates a smaller thickness distribution.

[0072] (Evaluation criteria for thickness distribution of rotational molded body) A: The difference between the maximum thickness and the minimum thickness is less than 0.8 mm. B: The difference between the maximum thickness and the minimum thickness is 0.8 mm or more.

[0073] [Example 1] Fluorine-based organic solvent (manufactured by AGC Inc., "ASAHIKLIN (registered trademark) AE-3000", CF ３ CH ２ OCF ２ CF ２ H) 1167 g and CH ２ =CH(CF ２ ) ４0.8 g of F(PFBE) and 9.9 g of methanol were charged into a pre-degassed polymerization vessel equipped with a stirrer and having an internal volume of 1.2 L. The solution in this polymerization vessel was heated to 72°C (polymerization temperature), and then 180 g of a mixed gas of TFE / ethylene = 88 / 12 (molar ratio) was charged, and then the pressure in the polymerization vessel was increased to 1.5 MPa [gauge]. Initially, 2.0 mL of a polymerization initiator solution in which tert-butyl peroxypivalate (PBPV) was dissolved in AE-3000 at a concentration of 1 mass% was charged, and polymerization was carried out. Furthermore, a mixed gas of TFE / ethylene = 54 / 46 (molar ratio) was continuously charged so that the pressure in the polymerization vessel during the polymerization reaction was maintained at 1.5 MPa [gauge]. Furthermore, PFBE in an amount equivalent to 0.55 mol% relative to the total number of moles of TFE and ethylene charged during polymerization was continuously charged. The polymerization was terminated when the amount of TFE / ethylene introduced reached 90 g, and the same volume of water with a conductivity of 4.18 μS / cm was added to the obtained polymer, and the mixture was heated with stirring for 2 hours to remove the fluorine-based organic solvent, thereby obtaining a solid composition 1 of Example 1. The composition of copolymer 1 in solid composition 1 was TFE unit / E unit / PFBE unit (molar ratio) = 53.5 / 45.95 / 0.55. The term "PFBE unit" refers to the CH of each copolymer. ２ =CH(CF ２ ) ４ The unit is based on F. Solid Composition 1 had an MFR of 11 g / 10 min and a melting point of 269°C.

[0074] [Example 2] A solid composition 2 of Example 2 was obtained in the same manner as in Example 1, except that the amount of methanol initially charged into the polymerization vessel was changed to 14.0 g, the amount of polymerization initiator solution initially charged was changed to 3.0 mL, and the granulation conditions were changed as shown in Table 1. The composition of copolymer 2 in solid composition 2 was TFE unit / E unit / PFBE unit (molar ratio) = 53.4 / 46.05 / 0.55. The MFR of copolymer 2 was 28 g / 10 min, and the melting point was 269 ° C.

[0075] [Example 3] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 2.5 g and 10.2 g, respectively, the amount of polymerization initiator solution initially charged was changed to 3.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 0.91 mol% relative to the total moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 3 of Example 3 was obtained in the same manner as in Example 1. The composition of copolymer 3 in solid composition 3 was TFE unit / E unit / PFBE unit (molar ratio) = 54.0 / 45.1 / 0.9. The MFR of solid composition 3 was 12 g / 10 min, and the melting point was 265 ° C.

[0076] [Example 4] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 3.0 g and 14.7 g, respectively, the amount of polymerization initiator solution initially charged was changed to 3.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 1.01 mol% relative to the total moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 4 of Example 4 was obtained in the same manner as in Example 1. The composition of copolymer 4 in solid composition 4 was TFE unit / E unit / PFBE unit (molar ratio) = 53.4 / 45.6 / 1.0. The MFR of solid composition 4 was 32 g / 10 min, and the melting point was 264 ° C.

[0077] [Example 5] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 5.9 g and 4.7 g, respectively, the amount of polymerization initiator solution initially charged was changed to 5.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 1.63 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 5 of Example 5 was obtained in the same manner as in Example 1. The composition of copolymer 5 in solid composition 5 was TFE unit / E unit / PFBE unit (molar ratio) = 53.6 / 44.8 / 1.6. The MFR of solid composition 5 was 7 g / 10 min, and the melting point was 258 ° C.

[0078] [Example 6] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 6.3 g and 7.6 g, respectively, the amount of polymerization initiator solution initially charged was changed to 5.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 1.73 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 6 of Example 6 was obtained in the same manner as in Example 1. The composition of copolymer 6 in solid composition 6 was TFE unit / E unit / PFBE unit (molar ratio) = 53.4 / 44.9 / 1.7. The MFR of solid composition 6 was 22 g / 10 min, and the melting point was 257 ° C.

[0079] [Example 7] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 8.3 g and 6.1 g, respectively, the amount of polymerization initiator solution initially charged was changed to 6.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 2.15 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 7 of Example 7 was obtained in the same manner as in Example 1. The composition of copolymer 7 in solid composition 7 was TFE unit / E unit / PFBE unit (molar ratio) = 53.5 / 44.4 / 2.1. The MFR of solid composition 7 was 16 g / 10 min, and the melting point was 253 ° C.

[0080] [Example 8] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 8.8 g and 6.7 g, respectively, the amount of polymerization initiator solution initially charged was changed to 8.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 2.25 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 8 of Example 8 was obtained in the same manner as in Example 1. The composition of copolymer 8 in solid composition 8 was TFE unit / E unit / PFBE unit (molar ratio) = 53.4 / 44.3 / 2.2. The MFR of solid composition 8 was 21 g / 10 min, and the melting point was 252 ° C.

[0081] [Example 9] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 11.2 g and 6.8 g, respectively, the amount of polymerization initiator solution initially charged was changed to 8.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 2.77 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 9 of Example 9 was obtained in the same manner as in Example 1. The composition of copolymer 9 in solid composition 9 was TFE unit / E unit / PFBE unit (molar ratio) = 53.4 / 43.9 / 2.7. The MFR of solid composition 9 was 23 g / 10 min, and the melting point was 246 ° C.

[0082] [Example 10] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 13.1 g and 6.7 g, respectively, the amount of polymerization initiator solution initially charged was changed to 10.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount equivalent to 3.20 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 1. Except for this, a solid composition 10 of Example 10 was obtained in the same manner as in Example 1. The composition of copolymer 10 in solid composition 10 was TFE unit / E unit / PFBE unit (molar ratio) = 53.1 / 43.8 / 3.1. The MFR of solid composition 10 was 21 g / 10 min, and the melting point was 242 ° C.

[0083] Example 11 A solid composition 11 of Example 11 was obtained in the same manner as in Example 1, except that the amounts of PFBE and methanol initially charged into the polymerization vessel were changed to 13.7 g and 3.1 g, respectively, the solution in the polymerization vessel was heated to 66°C (polymerization temperature), 179 g of a mixed gas of TFE / ethylene = 90 / 10 (molar ratio) was further charged, and then the amount of a polymerization initiator solution in which tert-butyl peroxypivalate was dissolved in AE-3000 at a concentration of 2 mass% was changed to 13.5 mL initially, the mixed gas continuously charged during polymerization was changed to TFE / ethylene = 60 / 40 (molar ratio), the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 3.31 mol % with respect to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. The composition of Copolymer 11 in Solid Composition 11 was TFE unit / E unit / PFBE unit (molar ratio) = 57.1 / 39.7 / 3.2. Solid Composition 11 had an MFR of 6 g / 10 min and a melting point of 234°C.

[0084] [Example 12] The amount of PFBE initially charged into the polymerization vessel was changed to 18.1 g, the amount of methanol to 4.1 g, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 4.06 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 12 of Example 12 was obtained in the same manner as in Example 11. The composition of copolymer 12 in solid composition 12 was TFE unit / E unit / PFBE unit (molar ratio) = 56.9 / 39.2 / 3.9. The MFR of solid composition 12 was 13 g / 10 min, and the melting point was 227 ° C.

[0085] [Example 13] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 16.2 g and 5.3 g, respectively, the amount of polymerization initiator solution initially charged was changed to 13.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 3.73 mol% relative to the total moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, the same procedure as in Example 11 was carried out to obtain solid composition 13 of Example 13. The composition of copolymer 13 in solid composition 13 was TFE unit / E unit / PFBE unit (molar ratio) = 57.2 / 39.2 / 3.6. The MFR of solid composition 13 was 37 g / 10 min, and the melting point was 230 ° C.

[0086] [Example 14] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 6.8 g and 7.0 g, respectively, the amount of polymerization initiator solution initially charged was changed to 6.5 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 2.15 mol% relative to the total moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 14 of Example 14 was obtained in the same manner as in Example 11. The composition of copolymer 14 in solid composition 14 was TFE unit / E unit / PFBE unit (molar ratio) = 58.2 / 39.7 / 2.1. The MFR of solid composition 14 was 21 g / 10 min, and the melting point was 245 ° C.

[0087] [Example 15] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 11.2 g and 6.8 g, respectively, the amount of polymerization initiator solution initially charged was changed to 8.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 2.77 mol% relative to the total moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 15 of Example 15 was obtained in the same manner as in Example 1. The composition of copolymer 15 in solid composition 15 was TFE unit / E unit / PFBE unit (molar ratio) = 53.2 / 44.1 / 2.7. The MFR of solid composition 15 was 22 g / 10 min, and the melting point was 246 ° C.

[0088] [Example 16] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 8.8 g and 6.7 g, respectively, the amount of polymerization initiator solution initially charged was changed to 8.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount equivalent to 2.25 mol% relative to the total number of moles of TFE and ethylene, water with a conductivity of 0.09 μS / cm was added to the resulting polymer, the fluorine-based organic solvent was removed by heating, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 16 of Example 16 was obtained in the same manner as in Example 1. The composition of copolymer 16 in solid composition 16 was TFE unit / E unit / PFBE unit (molar ratio) = 53.5 / 44.3 / 2.2. The MFR of solid composition 16 was 20 g / 10 min, and the melting point was 252 ° C.

[0089] [Example 17] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 21.8 g and 4.7 g, respectively, the amount of polymerization initiator solution initially charged was changed to 15.5 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 4.71 mol% relative to the total moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 17 of Example 17 was obtained in the same manner as in Example 11. The composition of copolymer 17 in solid composition 17 was TFE unit / E unit / PFBE unit (molar ratio) = 56.5 / 39.0 / 4.5. The MFR of solid composition 17 was 13 g / 10 min, and the melting point was 220 ° C.

[0090] [Example 18] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 0.1 g and 6.1 g, respectively, the amount of polymerization initiator solution initially charged was changed to 2.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 0.30 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 18 of Example 18 was obtained in the same manner as in Example 1. The composition of copolymer 18 in solid composition 18 was TFE unit / E unit / PFBE unit (molar ratio) = 54.5 / 45.2 / 0.3. The MFR of solid composition 18 was 3.0 g / 10 min, and the melting point was 271 ° C.

[0091] [Example 19] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 6.3 g and 12.3 g, respectively, the amount of polymerization initiator solution initially charged was changed to 5.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount corresponding to 1.73 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 19 of Example 19 was obtained in the same manner as in Example 1. The composition of copolymer 19 in solid composition 19 was TFE unit / E unit / PFBE unit (molar ratio) = 53.7 / 44.6 / 1.7. The MFR of solid composition 19 was 67 g / 10 min, and the melting point was 257 ° C.

[0092] [Example 20] The amount of PFBE and the amount of methanol initially charged into the polymerization vessel were changed to 3.0 g and 4.1 g, respectively, the amount of polymerization initiator solution initially charged was changed to 3.0 mL, the amount of PFBE continuously charged during polymerization was changed to an amount equivalent to 1.01 mol% relative to the total number of moles of TFE and ethylene, and the granulation conditions were changed as shown in Table 2. Except for this, a solid composition 20 of Example 20 was obtained in the same manner as in Example 1. The composition of copolymer 20 in solid composition 20 was TFE unit / E unit / PFBE unit (molar ratio) = 53.5 / 45.5 / 1.0. The MFR of solid composition 20 was 1.0 g / 10 min, and the melting point was 264 ° C.

[0093] The following table shows the composition of the copolymer for each example, as well as the measurement and evaluation results of the solid composition. In the table, the "TFE units" column indicates the content (unit: mol%) of TFE units relative to all units contained in the copolymer. The "E units (mol%)" column indicates the content (unit: mol%) of E units relative to all units contained in the copolymer. The "TFE / (TFE+E)" column indicates the content (unit: mol%) of TFE units relative to the total content of TFE units and E units. The "A units" column indicates the content (unit: mol%) of A units relative to all units contained in the copolymer. "MeOH" represents methanol. In the table, the "(PFBE+MeOH) / AE-3000" column indicates the total amount (unit: parts by mass) of PFBE and methanol used relative to 100 parts by mass of AE-3000 used.

[0094]

[0095]

[0096] As shown in Tables 1 and 2, it was confirmed that the solid composition of the present invention has excellent heat resistance and folding resistance, the coating film formed by electrostatic coating has excellent acid resistance, the coating film has small thickness variation, and the film formed by rotational molding has small thickness distribution (Examples 1 to 14).

[0097] The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2024-144353, filed on August 26, 2024, are incorporated herein by reference as part of the disclosure of the present invention.

Claims

1. A solid composition comprising a copolymer having units based on tetrafluoroethylene, units based on ethylene, and units based on at least one specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2), wherein the total content of the units based on tetrafluoroethylene and the units based on ethylene is 80.00 to 99.50 mol% based on all units of the copolymer, the content of the units based on the specific compound is 0.50 to 4.00 mol% based on all units of the copolymer, and the amount of metal elution calculated by Test 1 is 5.0 μg / cm ２ Super 40.0μg / cm ２ A solid composition having a melt flow rate of 2 to 50 g / 10 min measured in accordance with ASTM D3169 at a temperature of 297°C and a load of 49 N. Test 1: The solid composition is immersed in ultrapure water at 85°C for 7 days, and the amount of metal elements eluted into the ultrapure water is measured. CZ ２ =CX(CF ２ ) ｍ Y Formula (1) CF ２ =CF-O-(CF ２ ) ｎ F Formula (2) In formula (1), X, Y, and Z each independently represent a hydrogen atom or a fluorine atom, and m represents an integer of 2 to 6. Two Zs may be the same or different. In formula (2), n represents an integer of 1 to 6.

2. The solid composition according to claim 1, wherein the copolymer is a copolymer consisting only of units based on tetrafluoroethylene, units based on ethylene, and units based on at least one specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2).

3. The solid composition according to claim 1, wherein the specific compound is a compound represented by formula (1).

4. The solid composition according to claim 1 or 2, wherein the content of units based on tetrafluoroethylene is 49.00 to 60.00 mol % based on all units contained in the copolymer.

5. The solid composition according to claim 1 or 2, wherein the content of the ethylene-based units is 38.00 to 49.00 mol % based on the total units contained in the copolymer.

6. The solid composition according to claim 1 or 2, wherein the melting point of the copolymer is 210°C to 290°C.

7. A method for producing a solid composition according to claim 1 or 2, comprising polymerizing a monomer comprising tetrafluoroethylene, ethylene, and at least one specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2) in a polymerization solvent, heating the resulting copolymer with the polymerization solvent and water while stirring to form granules, and recovering the granules to obtain a solid composition.

8. The method for producing a solid composition according to claim 7, wherein the amount of the specific compound used is 0.10 to 2.80 parts by mass per 100 parts by mass of the polymerization solvent.

9. The method for producing a solid composition according to claim 7, wherein the water is ultrapure water.

10. The method for producing a solid composition according to claim 7, wherein the electrical conductivity of the water is 1.00 to 7.00 μS / cm.

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

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