Solid material, composition, and molded body

Abstract

The present invention addresses the problem of providing a solid material from which a molded body having excellent surface properties can be formed. The present invention also addresses the problem of providing: a composition which contains the solid material; a molded body which is obtained by molding the solid material; and a molded body which is obtained by molding the composition.　A solid material according to the present invention comprises: a copolymer which contains a unit based on tetrafluoroethylene, a unit based on ethylene, and a unit based on a specific compound that is selected from the group consisting of a compound represented by formula (1) CX1 2=CX2(CF2)mX3 and a compound represented by formula (2) CF2=CF-O-(CF2)nF; the specific compound; and a solvent that is a compound different from the specific compound. The ratio of the content of the specific compound to the total content of the solvent and the specific compound is 50.0 mass% or less.

Description

Solids, compositions and molded bodies

[0001] The present invention relates to solids, compositions and shaped bodies.

[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 ETFE is used as the constituent material of molded body, it is required to be excellent in various performances, and specifically, it is required to be able to produce the molded body with excellent surface properties.The present inventors refer to the method described in above-mentioned Patent Document 1 to produce ETFE, and evaluate the molded body formed by using the ETFE that is produced, and find that there is room for improvement in the surface properties of the molded body that is obtained.

[0005] Therefore, an object of the present invention is to provide a solid material that can form a molded article having excellent surface properties. Another object of the present invention is to provide a composition containing the solid material, a molded article obtained by molding the solid material, and a molded article obtained by molding the composition.

[0006] As a result of intensive research into the above-mentioned problems, the present inventors have found that a molded article having excellent surface properties can be formed by using a solid material containing a copolymer including units based on tetrafluoroethylene, units based on ethylene, and units based on a specific compound described below, the specific compound, and a solvent that is a compound different from the specific compound, wherein the ratio of the content of the specific compound to the total content of the solvent and the specific compound is 50.0 mass % or less, and have arrived at the present invention.

[0007] That is, the inventors have found that the above-mentioned problems can be solved by the following configurations. [1] A solid product comprising a copolymer containing units based on tetrafluoroethylene, units based on ethylene, and units based on a specific compound selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2), the specific compound, and a solvent that is a compound different from the specific compound, wherein the ratio of the content of the specific compound to the total content of the solvent and the specific compound is 50.0 mass % or less. [2] The solid product according to [1], wherein the content of the units based on tetrafluoroethylene is 48.00 to 64.90 mol % based on all units contained in the copolymer. [3] The solid product according to [1] or [2], wherein the content of the units based on ethylene is 35.00 to 51.90 mol % based on all units contained in the copolymer. [4] The solid product according to any of [1] to [3], wherein the content of the units based on the specific compound in the copolymer is 0.10 to 5.00 mol % based on all units contained in the copolymer. [5] The solid material according to any one of [1] to [4], wherein the solvent comprises a fluorine-containing solvent. [6] The solid material according to [5], wherein the fluorine-containing solvent comprises at least one selected from the group consisting of chlorofluorocarbons, perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers. [7] The solid material according to any one of [1] to [6], wherein the solvent comprises water. [8] The solid material according to any one of [1] to [7], wherein the content of the solvent is 0.01 to 2 mass% relative to the total mass of the solid material. [9] The solid material according to any one of [1] to [7], wherein the content of the solvent is 0.01 to 2 mass% relative to the total mass of the solid material.

[10] The solid material according to any one of [1] to [7], wherein the specific surface area is 0.3 m ２ / g or more.

[10] A composition comprising the solid according to any one of [1] to [9] and at least one component selected from the group consisting of a resin other than the copolymer, a heat stabilizer, an antioxidant, a colorant, an ultraviolet absorber, a filler, a crosslinking agent, a crosslinking aid, and an organic peroxide.

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

[10] .

[12] A molded article obtained by molding the composition according to

[10] .

[0008] According to the present invention, a solid material capable of forming a molded article having excellent surface properties can be provided. Furthermore, according to the present invention, a composition containing the solid material, a molded article obtained by molding the solid material, and a molded article obtained by molding the composition can be provided.

[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 ​​written before and after "to" as the upper and lower limits. In the numerical ranges described in stages in this specification, 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 used alone or in combination with two or more substances corresponding to the component. 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 the atomic group derived from one molecule of the above-mentioned monomer, which is directly formed by polymerizing the monomer, and the atomic group obtained by chemically converting a part of the above-mentioned atomic group.In the following, in some cases, the unit derived from each monomer will be described by adding "unit" to the name of the monomer.A "TFE unit" is a unit based on tetrafluoroethylene of the copolymer, and an "E unit" is a unit based on ethylene of the copolymer.In addition, an "A unit" is a unit based on a specific compound described below.A "solvent" means a substance that is liquid at 25°C and 1013hPa.

[0011] [Solid] The solid of the present invention (hereinafter also referred to as "the solid") comprises a copolymer containing TFE units, E units, and A units based on a specific compound described below, and further comprises a specific compound and a solvent which is a compound different from the specific compound.Furthermore, the solid is characterized in that the ratio of the content of the specific compound to the total content of the solvent and the specific compound (hereinafter also referred to as "ratio P") is 50.0 mass% or less.

[0012] By using this solid material, a molded product with excellent surface properties can be formed. While the details of the reason for this are not yet clear, it is believed that the content of the specific compound in the components used to produce the copolymer or solid material in this solid material is below a predetermined value. Because the specific compound is relatively lipophilic, it is believed to remain in the solid material. If the solid material contains a larger amount of the specific compound than the solvent, it is presumed that bubbles originating from the specific compound will be generated by heating during molding when the solid material is used to form a molded product. As a result, it is presumed that voids (holes), which are traces of bubbles, will be generated on the surface of the molded product. In contrast, since the content of the specific compound relative to the total content of the solvent and the specific compound is below a predetermined value, it is presumed that the specific compound is less likely to remain in the solid material. As a result, bubbles are less likely to be generated during molding, and the number of voids formed on the surface of the molded product is reduced, resulting in better surface properties of the molded product. Here, a molded product with excellent surface properties refers to a molded product in which the generation of voids (bubbles) caused by the specific compound is suppressed on the surface of the molded product.

[0013] Each component contained in the solid material will be explained below.

[0014] [Copolymer] The present solid contains a copolymer containing E units, TFE units, and A units. Hereinafter, unless otherwise specified, the mere expression "copolymer" means a copolymer containing E units, TFE units, and A units.

[0015] The copolymer contains TFE units based on tetrafluoroethylene, E units based on ethylene, and A units based on a specific compound selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2).

[0016] CX １ ２ =CX ２ (CF ２ ) ｍ X ３ Formula (1) CF ２ =CF-O-(CF ２ ) ｎ F Formula (2) In Formula (1), X １ , X ２ and X ３ each independently represents a hydrogen atom or a fluorine atom, and m represents an integer of 1 to 6. In formula (2), n represents an integer of 1 to 6.

[0017] In the compound represented by formula (1), X １ is preferably a hydrogen atom from the viewpoint of polymerizability. ２ is preferably a hydrogen atom from the viewpoint of polymerizability. ３ is preferably a fluorine atom. m is preferably an integer of 2 to 6, more preferably an integer of 3 to 6, and even more preferably 3 or 4.

[0018] 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 ) ６F, 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.

[0019] 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.

[0020] 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. In other words, 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.

[0021] 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 from the viewpoint of excellent long-term folding endurance, a copolymer containing E units, TFE units and A1 units is more preferred.

[0022] The content of TFE units is preferably 45.00 to 69.99 mol%, more preferably 48.00 to 64.90 mol%, and even more preferably 50.00 to 64.50 mol%, based on the total units contained in the copolymer. If the content is equal to or greater than the lower limit, the heat resistance of the molded article will be superior, and if the content is equal to or less than the upper limit, the mechanical properties of the molded article will be superior.

[0023] The content of E units is preferably 30.00 to 54.99 mol%, more preferably 35.00 to 51.90 mol%, and even more preferably 35.00 to 49.50 mol%, based on the total units contained in the copolymer. If the content is equal to or greater than the lower limit, the mechanical properties of the molded article will be superior, and if it is equal to or less than the upper limit, the heat resistance of the molded article will be superior.

[0024] The content of A units is preferably 0.01 to 10.0 mol %, more preferably 0.10 to 5.00 mol %, and even more preferably 0.50 to 4.00 mol %, based on the total units contained in the copolymer. If the content is equal to or greater than the lower limit, a molded article having excellent abrasion resistance can be formed, and if the content is equal to or less than the upper limit, a molded article having excellent dimensional stability can be formed.

[0025] In the copolymer, the total content of TFE units and E units is preferably 90.00 to 99.99 mol%, more preferably 95.00 to 99.90 mol%, and even more preferably 96.00 to 99.50 mol%, based on all units contained in the copolymer.

[0026] The copolymer may contain units based on other monomers other than tetrafluoroethylene, ethylene, and the specific compound. Specific examples of other monomers 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.

[0027] 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.

[0028] As copolymer, the embodiment that comprises TFE unit, E unit and A unit is preferred, and the embodiment that comprises TFE unit, E unit and A1 unit is more preferred.The content of copolymer in this solid is preferably 99% by mass or more, more preferably 99.5% by mass or more, and even more preferably 99.8% by mass or more, from the viewpoint that the crushability of this solid is more excellent.The content of copolymer in this solid is preferably 99.99% by mass or less, from the viewpoint that the bending resistance of molded body is more excellent.

[0029] <Melt Flow Rate> The melt flow rate (hereinafter also referred to as "MFR") of the copolymer is preferably 1 to 60 g / 10 min, more preferably 2 to 50 g / 10 min. When the MFR of the copolymer is equal to or greater than the above-mentioned lower limit, a molded article with excellent fluidity can be formed during melt molding. Furthermore, when the MFR of the copolymer is equal to or less than the above-mentioned upper limit, a molded article with excellent abrasion resistance at high temperatures can be formed. A specific example of a method for adjusting the MFR of the copolymer within the above range is to adjust the molecular weight of the copolymer. The higher the molecular weight of the copolymer, the smaller the MFR. The MFR of the copolymer can be obtained by measuring the mass of a solid material flowing from an orifice with a diameter of 2 mm and a length of 8 mm over 10 minutes at a temperature of 297°C and a load of 49 N in accordance with ASTM D3159. The copolymer is the main component of the solid material, and components other than the copolymer have little effect on the MFR measurement. Therefore, the measured MFR obtained by measuring the solid material can be considered the MFR of the copolymer.

[0030] <Melting Point> The melting point of the copolymer is preferably 210°C or higher, more preferably 215°C or higher, and even more preferably 220°C or higher, in order to provide a molded article with superior mechanical strength when used at high temperatures. The upper limit of the melting point of the copolymer is preferably 290°C or lower, more preferably 280°C or lower, and particularly preferably 270°C or lower, in order to provide superior moldability of the solid product. Specific examples of methods for adjusting the melting point of the copolymer within the above range include lowering the polymerization temperature during copolymer production and adjusting the content of A units in the copolymer. The melting point of the copolymer is the temperature corresponding to the endothermic peak detected when a solid product is heated at a rate of 10°C / min in an air atmosphere using a differential scanning calorimeter. As with MFR, the measured melting point obtained by measuring a solid product can be considered to be the melting point of the copolymer.

[0031] [Specific Compound] The present solid contains a specific compound. Specific examples and preferred embodiments of the specific compound are the same as those of the specific compound from which the A unit is derived.

[0032] The specific compound contained in the present solid may be both the compound represented by formula (1) and the compound represented by formula (2), but one of the compound represented by formula (1) and the compound represented by formula (2) is preferred, and the compound represented by formula (1) is more preferred.In addition, the specific compound from which the A unit contained in the copolymer is derived and the specific compound contained in the present solid are preferably the same.For example, when the copolymer contains PFBE units as A units, the present solid preferably contains PFBE as the specific compound.

[0033] The content of the specific compound contained in the solid material is preferably 0.05% by mass or less, more preferably 0.045% by mass or less, and even more preferably 0.04% by mass or less, from the viewpoint of providing better surface properties of the molded article, and is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more, from the viewpoint of providing better bending resistance of the molded article.

[0034] The contents of the specific compounds and the solvents (excluding water) described below contained in the solid material can be measured by analyzing the volatile components when the solid material is heated to 240°C using a headspace GC / MS device.

[0035] [Solvent] The present solid material contains a solvent. However, the solvent contained in the present solid material is a compound different from the specific compound. Specific examples of the solvent contained in the present solid material include water and organic solvents such as hydrofluorocarbons, hydrofluoroethers, perfluorocarbons, chlorofluorocarbons, alcohols, and hydrocarbons.

[0036] The present solid preferably contains a fluorine-containing solvent as a solvent. A fluorine-containing solvent refers to an organic solvent containing at least one fluorine atom. Examples of fluorine-containing solvents include chlorofluorocarbons, perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers. The number of carbon atoms in the fluorine-containing solvent is preferably 2 to 7, and more preferably 2 to 6. The present solid preferably contains at least one selected from the group consisting of chlorofluorocarbons, perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers, and more preferably contains at least one selected from the group consisting of hydrofluorocarbons and hydrofluoroethers.

[0037] Hydrofluorocarbons are fluorine-containing solvents consisting of hydrogen atoms, fluorine atoms, and carbon atoms, and containing no heteroatoms other than fluorine atoms. The number of carbon atoms in the hydrofluorocarbon is preferably 3 to 7, and more preferably 4 to 6. The hydrofluoroether preferably contains one ether bond.

[0038] Specific examples of hydrofluorocarbons include CF ３ CFHCF ２ CF ２ CF ３ , C.F. ３ (CF ２ ) ４ H, C.F. ３ CF ２ CFHCF ２ CF ３ , C.F. ３ CFHCFHCF ２ CF ３ , C.F. ２ HCFHCF ２ CF ２ CF ３ , C.F. ３ (CF ２ ) ５ H, C.F. ３ CH (CF ３ )CF ２ CF ２ CF ３ , C.F. ３ CF (CF ３ ) CFHCF２ CF ３ , C.F. ３ CH (CF ３ ) CFHCF ２ CF ３ , C.F. ３ CF ２ CH ２ CH ３ , and CF ３ (CF ２ ) ３ CH ２ CH ３ , 1,1,2,2-tetrafluorocyclobutane, CF ３ CFHCFHCF ３ , C.F. ３ CF (CF ３ ) CFHCFHCF ３ , C.F. ３ CH ２ CF ２ CH ３ , C.F. ２ ClCFCl ２ , C.F. ２ ClCCl ２ F and CF ３ CClFCFClCF ３ Among them, CF ３ (CF ２ ) ５ H or CF ３ CH ２ CF ２ CH ３ is preferred.

[0039] The hydrofluoroether is a fluorine-containing solvent having an ether bond and containing a hydrogen atom and a fluorine atom. The number of carbon atoms in the hydrofluoroether is preferably 3 to 7, more preferably 4 to 6, and even more preferably 4 or 5. The hydrofluoroether preferably contains one ether bond.

[0040] Specific examples of hydrofluoroethers include CF ３ CH ２ OCF ２ CF ２ H, C.F. ３ (CF ３ ) CFCF ２ OCH ３ , C.F.３ (CF ２ ) ３ OCH ３ , C.F. ３ (CF ２ ) ３ O.C. ２ H ５、 CF ３ (CF ２ ) ２ C ３ F ７ OCH ３ , and (CF ３ ) ２ CFOCH ３ CF ３ CH ２ OCF ２ CF ２ H is preferred.

[0041] When the present solid contains a fluorine-containing solvent, the content of the fluorine-containing solvent is preferably from 0.0001 to 0.5% by mass, more preferably from 0.0001 to 0.4% by mass, based on the total mass of the solid.

[0042] In addition, in the present solid material, the solvent preferably contains water. When the present solid material contains water, handling properties during transportation are superior.

[0043] When the solid contains water, the water content is preferably 0.01 to 0.5% by mass, more preferably 0.01 to 0.2% by mass, based on the total mass of the solid. The water content in the solid is determined from the difference between the weight loss of the solid measured using a thermogravimetric differential thermal analyzer and the total content of the solvent and specific compound in the solid measured using a headspace GC / MS. More detailed measurement methods are described in the Examples below.

[0044] <Ratio P> As described above, the present solid has a ratio P, which is the ratio of the content of the specific compound to the total content of the solvent and the specific compound ((content of the specific compound) / (content of the solvent+content of the specific compound)), of 50.0 mass% or less. The ratio P is preferably 0.1 to 50.0 mass%, and more preferably 0.5 to 50.0 mass%. If the ratio P is equal to or less than the upper limit, a molded product with better surface properties can be formed, and if the ratio P is equal to or more than the lower limit, the cohesion of the solid is reduced and the flowability is better.

[0045] In the present solid material, the content of the solvent is preferably 0.001 to 2.5% by mass, more preferably 0.01 to 2% by mass, and even more preferably 0.01 to 1% by mass, based on the total mass of the solid material.

[0046] The solid may be in the form of, for example, granules (beads), pellets, threads, or the like.

[0047] [Specific surface area] The specific surface area of ​​a solid is 0.3 m ２ / g or more is preferable, and 0.5m ２ / g or more is more preferable, and 5m ２ / g or more is more preferable, and 10m ２ / g or more is particularly preferred, and ２ / g or less is preferable, and 30m ２ When the specific surface area of ​​the solid substance is equal to or greater than the above lower limit, a molded article having more excellent surface properties can be formed.

[0048] The specific surface area of ​​a solid is the BET specific surface area (unit: m) per mass of the solid measured by the BET method based on the amount of nitrogen adsorbed on the surface of the solid. ２ / g). The specific surface area of ​​the solid material can be measured using a known specific surface area measuring device (for example, a product manufactured by Microtrac-Bell, trade name "BELSORP MINI X"). The specific surface area of ​​the solid material can be controlled, for example, by adjusting the drying conditions when drying the granulated material containing the copolymer in the production method of the solid material described below.

[0049] [Method for producing solid material] The present solid material can be produced, for example, by a method comprising polymerizing the above-mentioned monomers (tetrafluoroethylene, ethylene, and the specific compound) in a polymerization solvent to produce a copolymer, granulating the mixture containing the copolymer, the polymerization solvent, and water by heating with stirring, and drying the resulting granules, wherein the granules are dried in two stages: a first stage in which the granules are dried under normal pressure, and a second stage in which the granules are dried under vacuum. Hereinafter, the above-mentioned method, which is an example of a method for producing the present solid material, will be described.

[0050] <Production of Copolymer> The copolymer can be produced by polymerizing the above-mentioned monomers (tetrafluoroethylene, ethylene, and the specific compound) in a polymerization solvent by a known method such as bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization, and among these, production by solution polymerization is preferred. In producing the copolymer, in addition to the above-mentioned monomers and polymerization solvent, a polymerization initiator, a chain transfer agent, etc. can be used.

[0051] 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 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, particularly preferably 0.05 to 0.5 parts by mass, per 100 parts by mass of the amount of the monomer used.

[0052] As the polymerization solvent, a fluorine-containing solvent such as hydrofluorocarbon, hydrofluoroether, perfluorocarbon, or chlorofluorocarbon can be used. The polymerization solvent may be used alone or in combination of two or more. As the polymerization solvent, a fluorine-containing solvent is preferably used, more preferably a hydrofluorocarbon, hydrofluoroether, perfluorocarbon, or chlorofluorocarbon, and even more preferably a hydrofluorocarbon or hydrofluoroether. The amount of the polymerization solvent used is preferably 5 times or more, more preferably 7 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.

[0053] In the production of the copolymer, a chain transfer agent may be used, and is preferably used. The chain transfer agent has a large chain transfer constant and can be added in a small amount, and is preferably an alcohol such as methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3,3-hexafluoroisopropanol, or 2,2,3,3,3-pentafluoropropanol; ２ H ２ Preferred are hydrofluorocarbons such as n-pentane, n-hexane, and cyclohexane; 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, with at least one selected from the group consisting of alcohols and hydrocarbons being more preferred, and alcohols being even more preferred, due to their higher chain transfer constant and high stability of the end groups of the copolymer. Among alcohols, methanol or ethanol is particularly preferred. Among these, methanol is most preferred due to its 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, relative to the amount of monomer used. Also, the amount is preferably 5 times or less, more preferably 4 times or less.

[0054] The polymerization temperature is preferably 15 to 90°C, more preferably 20 to 85°C, and particularly preferably 25 to 80°C. When the polymerization temperature is equal to or higher than the lower limit, the polymerizability is excellent. When the polymerization temperature is equal to or lower than the upper limit, the melting point of the copolymer can be improved. The polymerization pressure is preferably 0.5 to 3.0 MPa, and particularly preferably 0.9 to 2.5 MPa. The polymerization time is preferably 1 to 12 hours.

[0055] <Granulation> Next, a mixture containing the obtained copolymer, polymerization solvent, and water is heated with stirring to carry out granulation to produce a granulated product containing the copolymer.

[0056] In granulation, a mixture containing the copolymer, polymerization solvent, and water is first 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 the copolymer production may be used as is, or a concentrated slurry of the above slurry, or a slurry obtained by diluting the above 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.

[0057] 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 already filled 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 contents, and a discharge means for discharging 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.

[0058] The heating temperature of the mixture during granulation is preferably in the range of 25 to 110°C, more preferably in the range of 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 pressure described herein is a gauge pressure based on atmospheric pressure. The granulation time may be, for example, 1 to 24 hours, preferably 1 to 15 hours. The timing for terminating granulation may be, for example, when a period of time has elapsed during which the volume of the mixture contained in the granulation tank has not decreased. When it has been confirmed that the volume of the mixture in the granulation tank has remained constant for a predetermined period of time without decreasing, it can be assumed that the components such as the solvent discharged from the granulation tank during the granulation have been largely discharged.

[0059] <Drying> Next, the granulated product containing the copolymer obtained by granulation is dried to produce the present solid product containing the copolymer.

[0060] From the viewpoint of producing a solid product having a low ratio P, it is preferable to produce a solid product containing a copolymer by drying the granulated product containing the copolymer in two stages: a first stage in which the granulated product is dried under normal pressure conditions, and a second stage in which the granulated product is dried under vacuum conditions. Here, normal pressure conditions mean that the pressure inside the vessel in which the drying treatment is carried out is 0 to 0.1 MPa, and vacuum conditions mean that the pressure inside the vessel in which the drying treatment is carried out is -0.01 to -0.1 MPa.

[0061] The granules obtained by the above granulation contain moisture, polymerization solvent, and specific compounds (hereinafter also collectively referred to as "vaporized substances"). In the subsequent drying process, these components vaporize, producing a solid having pores on the surface. According to the inventors' studies, it has been found that if the granules obtained by granulation are dried only under vacuum conditions, rather than under normal pressure conditions, a solid having a small specific surface area is obtained. From this, it is presumed that if the granules are dried only under vacuum conditions, the vaporized substances rapidly vaporize near the surface, while the size of the pores formed near the surface becomes small, making it easier for the vaporized substances (particularly the specific compounds) to remain inside the solid. In contrast, it has been found that if the granules obtained by granulation are subjected to two-stage drying, first drying under normal pressure conditions and then drying under vacuum conditions, a solid having a large specific surface area is obtained. From this, it is presumed that when the above-mentioned two-stage drying is carried out, the pores formed near the surface are large in size, drying proceeds inside the granules as well, and the vaporized substances are quickly vaporized and separated, resulting in a solid material with a low ratio P.

[0062] A specific example of the drying method is to transfer the granulated material from a granulation vessel to a drying vessel such as a dryer, heat the granulated material under a predetermined pressure condition, and vaporize and separate the vaporized substances contained in the granulated material. Examples of the dryer used for drying include a batch rotary dryer, an indirect heating dryer, a vacuum dryer, and a hot air dryer.

[0063] The pressure inside the vessel during the first stage drying is preferably 0 to 0.1 MPa, more preferably 0 to 0.08 MPa. The drying temperature in the first stage is preferably in the range of 30 to 150°C, more preferably 35 to 130°C. The drying time in the first stage is preferably 1 to 24 hours, more preferably 1 to 12 hours.

[0064] The pressure inside the vessel during the second-stage drying is preferably −0.01 to −0.1 MPa, more preferably −0.02 to −0.1 MPa. The drying temperature in the second stage is preferably in the range of 50 to 150° C., more preferably 60 to 150° C. The drying time in the second stage is preferably 1 to 24 hours, more preferably 1 to 12 hours.

[0065] Furthermore, it is preferable that the drying time for the first stage is 30 to 70% of the total drying time, and the drying time for the second stage is 70 to 30%, and it is more preferable that the drying time for the first stage is 30 to 60% and the drying time for the second stage is 40 to 70%.

[0066] The solid obtained by the above drying may be melted and extruded using an extruder to form a solid in other forms such as pellets or threads.

[0067] [Composition] The composition of the present invention (hereinafter also referred to as "the composition") contains the above-described solid and at least one component selected from the group consisting of other resins other than the copolymer, heat stabilizers, antioxidants, colorants, UV absorbers, fillers, crosslinking agents, crosslinking aids, and organic peroxides (hereinafter also referred to as "other components"). Because the composition contains the solid, molded articles with excellent surface properties can be formed by using the composition. The composition is preferably in a solid state. The content of the solid is preferably 50% by mass or more but less than 100% by mass, more preferably 70% by mass or more but less than 100% by mass, and even more preferably 90% by mass or more but less than 100% by mass, based on the total mass of the composition. The composition preferably does not contain any solvents or specific compounds other than those derived from the solid. The ratio of the content of the specific compound to the total content of the solvent and specific compound in the composition is preferably 0.1 to 50.0% by mass, more preferably 0.5 to 50.0% by mass.

[0068] The content of the "other components" in the composition 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 copolymer in the composition.

[0069] The present composition can be produced by melt-kneading the present solid or a powder obtained by pulverizing the present solid with the other components described above, if necessary, by a known method. The present solid can be pulverized using a known pulverizer, such as a rotor mill, hammer mill, turbo mill, or jet mill.

[0070] [Molded Article] The molded article of the present invention is obtained by molding the present solid or the present composition. Because the molded article of the present invention is formed using the present solid, the number of voids formed on the surface is small and the surface quality is excellent. Specific examples of molding methods include injection molding, extrusion molding, blow molding, press molding, rotational molding, electrostatic coating, and spray molding.

[0071] The molded article of the present invention may be a coating film formed using the present solid or the present composition. Examples of methods for forming a coating film include methods in which a powder obtained by pulverizing the present solid or the present composition containing the powder is used to form a coating film by rotational molding, electrostatic coating, or spray molding. The thickness of the coating film is preferably 1 μm to 10 mm, more preferably 50 μm to 5 mm, and even more preferably 100 μm to 3 mm.

[0072] 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.

[0073] The present solid, the present composition or the above-mentioned molded article 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 electrical 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, 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.; carrier films for fuel cells.In particular, the molded article of the present invention is particularly suitable for use as a chemical liquid transport member or coating material for semiconductor devices because of its excellent surface properties.

[0074] The present invention will be described in detail below with reference to examples. Examples 1 to 12 are working examples, and Examples 13 and 14 are comparative examples. However, the present invention is not limited to these examples. Various measurement methods and evaluation methods are as follows.

[0075] [Measurement] <Content of Solvent and Specific Compound in Solid> The content of the solvent and specific compound remaining in the solid was determined by analyzing the gas components present in the gas phase in the headspace when the solid was heated to 240°C using a headspace GC / MS device, and determining the content (mass%) of each component relative to the total mass of the copolymer. The water content in the solid was calculated from the difference between the weight loss of the solid measured using a thermogravimetric differential thermal analyzer (TG-DTA) and the total content of the solvent and specific compound in the solid measured using a headspace GC / MS device. The weight loss of the solid was determined by heating the solid from 30°C to 550°C at a heating rate of 10°C / min using a TG-DTA and measuring the weight of the solid before and after heating.

[0076] <Content of each unit in copolymer> The content (mol %) of each unit in the copolymer was calculated from the results of total fluorine measurement and melting F-NMR measurement. １ H and １３ Calculated by C-NMR measurement.

[0077] <MFR (Melt Flow Rate)> Using a melt indexer (manufactured by Techno Seven Co., Ltd.), the mass (g) of solid matter 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 the obtained measured value was taken as the MFR (g / 10 min) of the copolymer.

[0078] <Melting Point> The melting point (°C) of the copolymer was determined from an endothermic peak detected when a solid substance was heated to 300°C at a heating rate of 10°C / min in an air atmosphere using a differential scanning calorimeter (DSC7020 manufactured by SII Corporation).

[0079] <Specific Surface Area> The specific surface area of ​​the solid material was measured by the BET method using a BET specific surface area measuring device (manufactured by Microtrac-Bell, product name "BELSORP MINI X") based on the amount of nitrogen adsorbed onto the particle surface of the solid material. From the measured specific surface area value, the specific surface area of ​​the solid material of each example was evaluated according to the following criteria. (Evaluation criteria) ⊚: The measured value of the specific surface area is 20 m ２ / g or more. ○: The measured value of the specific surface area is 10 m ２ / g or more 20m ２ / g or less. △: The measured value of the specific surface area is 0.3 m ２ / g or more 10m ２ / g or less. ×: The measured value of the specific surface area is 0.3 m ２ / g or less.

[0080] [Evaluation Test] <Surface Texture> An injection molding machine (ROBOSHOT α-50C, manufactured by FANUC Corporation) was used. The mold was engraved to obtain molded articles with design dimensions of 12 mm width, 120 mm length, and 3 mm thickness, and a tunnel gate with a gate tip diameter of 1.0 mm was used. The solid product obtained in each example was molded to obtain a molded article under the following molding conditions: cylinder temperature: 310°C, mold temperature: 150°C, injection speed: 20 mm / sec, dwell pressure: 78.4 MPa, dwell time: 3 sec, and cooling time: 30 sec. The obtained injection-molded articles were visually observed and evaluated according to the following criteria. (Evaluation Criteria) ○: No voids were observed, and no poor appearance occurred. ×: Voids were observed.

[0081] [Example 1] A stainless steel polymerization vessel having an internal volume of 1.3 L (liters) and equipped with a stirrer and a jacket was evacuated, and then CF ３ CH ２ CF ２ CH ３ (hereinafter also referred to as "HFC-365mfc"), 0.8 L, 8.7 g of methanol, and the specific compound CH ２ =CH(CF ２ ) ４ 12.1 g of F(PFBE) and CF ２ = CFO (CF ２ ) ２ CF３ 0.4 g of tetrafluoroethylene (TFE) and ethylene (E) in a molar ratio of 83 / 17 (mol %) was added while stirring the mixture, and the inside of the polymerization vessel was pressurized to 1.5 MPaG (gauge pressure), and the temperature inside the polymerization vessel was raised to 72°C (polymerization temperature). After the temperature stabilized, a 1 mass % solution of tert-butyl peroxypivalate (PBPV) (solvent: CF ３ CH ２ OCF ２ CF ２ 17 mL of H (hereinafter also referred to as "AE-3000") was injected to initiate polymerization. During the polymerization, a TFE / E mixed gas having a TFE / E molar ratio of 54 / 46 (mol %) was added so that the internal pressure was constant at 1.5 MPaG. In addition, 1.2 mL of PFBE (an amount equivalent to 3.1 mol % relative to the total number of moles of TFE and E) was added every time 10 g of the TFE / E mixed gas added during the polymerization was consumed. When 100 g of the TFE / E mixed gas had been added, the polymerization vessel was cooled, and the polymerization was terminated, resulting in a copolymer of TFE, ethylene, PFBE, and PPVE.

[0082] Thereafter, residual monomer gas was purged from the polymerization vessel until the pressure inside the polymerization vessel reached 0.01 MPa, and the slurry was transferred to a vessel with an internal volume of 2.6 L, followed by the addition of water at the same volume as the slurry. The slurry was heated with stirring to evaporate the solvent and produce (granulate) a granulated product containing the copolymer. During granulation, the interior of the vessel was heated within a range of 30 to 100°C. Granulation was terminated when it was visually confirmed that the volume of the mixture containing the granulated product inside the vessel had not decreased and had become constant, thereby obtaining a granulated product. The obtained granulated product was placed in an oven heated to 120°C and dried for 90 minutes under normal pressure of 0.01 MPa, after which the oven was depressurized and the mixture was dried for 60 minutes under vacuum conditions of -0.07 MPa, yielding a granular solid product 1. Measurements using the above method confirmed that solid product 1 contained water, HFC-365mfc, PFBE, and PPVE.

[0083] [Example 2] When initially charged into the polymerization vessel, the amounts of methanol and PFBE were changed to 10.6 g and 9.6 g, respectively, and no PPVE was charged into the polymerization vessel. Furthermore, the amount of a 1% by mass solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and pressurization by adding a TFE / E mixed gas was changed to 13 mL. Furthermore, the amount of PFBE added during polymerization was changed to 1.0 mL for every 10 g of TFE / E mixed gas consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 1, except for the above changes. Subsequently, a granulated product containing the copolymer was obtained in the same manner as in Example 1, and the obtained granulated product was placed in an oven heated to 120°C and dried under normal pressure of 0.01 MPa for 150 minutes. Subsequently, the pressure in the oven was reduced, and the product was dried under vacuum at -0.05 MPa for 180 minutes, yielding a granular solid product 2. As a result of the measurement by the above method, it was confirmed that the solid substance 2 contained water, HFC-365mfc, and PFBE.

[0084] [Example 3] When initially charged into the polymerization vessel, the amount of methanol was changed to 4.6 g and the amount of PFBE was changed to 3.4 g. In addition, the amount of a 1% by mass solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and pressurization by adding a TFE / E mixed gas was changed to 5 mL. Furthermore, the amount of PFBE added during polymerization was changed to 0.4 mL per 10 g of TFE / E mixed gas consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2, except for the above changes. Thereafter, a granulated product containing the copolymer was obtained in the same manner as in Example 1, and the obtained granulated product was placed in an oven heated to 120°C and dried under normal pressure of 0.01 MPa for 180 minutes. Subsequently, the pressure in the oven was reduced, and the product was dried under vacuum at -0.09 MPa for 240 minutes to obtain a granular solid product 3. As a result of the measurement by the above method, it was confirmed that the solid substance 3 contained water, HFC-365mfc, and PFBE.

[0085] Example 4 When initially charging the polymerization vessel, 0.8 L of 2,3-dichlorooctafluorobutane was added instead of 0.8 L of HFC-365mfc, and the amounts of methanol and PFBE were changed to 20.8 g and 5.9 g, respectively. Furthermore, the amount of a 1 mass % solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and pressurization by adding a TFE / E mixed gas was changed to 5 mL. Furthermore, during polymerization, 0.4 mL of PFBE was added every time 10 g of the added TFE / E mixed gas was consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2, except for the above changes. Thereafter, a granulated product containing a copolymer was obtained in the same manner as in Example 1, and the obtained granulated product was placed in an oven heated to 120°C and dried for 95 minutes under normal pressure of 0.01 MPa, and then the pressure inside the oven was reduced and the product was dried for 85 minutes under vacuum conditions of -0.09 MPa to obtain a granular solid product 4. As a result of measurement by the above method, it was confirmed that solid product 4 contained water, 2,3-dichlorooctafluorobutane, and PFBE.

[0086] [Example 5] When initially charged into the polymerization vessel, the amount of methanol was changed to 16.6 g and the amount of PFBE was changed to 6.7 g. In addition, the amount of a 1% by mass solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and pressurization by adding a TFE / E mixed gas was changed to 9 mL. Furthermore, the amount of PFBE added during polymerization was changed to 0.7 mL per 10 g of TFE / E mixed gas consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2, except for the above changes. Thereafter, a granulated product containing the copolymer was obtained in the same manner as in Example 1, and the obtained granulated product was placed in an oven heated to 120°C and dried under normal pressure of 0.01 MPa for 85 minutes. Subsequently, the pressure in the oven was reduced, and the product was dried under vacuum at -0.07 MPa for 120 minutes, yielding a granular solid product 5. As a result of the measurement by the above method, it was confirmed that the solid substance 5 contained water, HFC-365mfc, and PFBE.

[0087] [Example 6] When initially charged into the polymerization vessel, the amount of methanol was changed to 10.4 g and the amount of PFBE was changed to 7.1 g. In addition, the amount of a 1% by mass solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and pressurization by adding a TFE / E mixed gas was changed to 10 mL. Furthermore, during polymerization, the amount of PFBE added per 10 g of TFE / E mixed gas consumed was changed to 0.8 mL. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2, except for the above changes. Thereafter, a granulated product containing the copolymer was obtained in the same manner as in Example 1, and the obtained granulated product was placed in an oven heated to 120°C and dried under normal pressure of 0.01 MPa for 150 minutes. Subsequently, the pressure in the oven was reduced, and the product was dried under vacuum at -0.05 MPa for 180 minutes to obtain a granular solid product 6. As a result of the measurement by the above method, it was confirmed that the solid substance 6 contained water, HFC-365mfc, and PFBE.

[0088] [Example 7] When initially charged into the polymerization vessel, the amount of methanol was changed to 15.8 g and the amount of PFBE was changed to 5.9 g. In addition, the amount of a 1% by mass solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and pressurization by adding a TFE / E mixed gas was changed to 8 mL. Furthermore, the amount of PFBE added during polymerization was changed to 0.7 mL per 10 g of TFE / E mixed gas consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2, except for the above changes. Thereafter, a granulated product containing the copolymer was obtained in the same manner as in Example 1, and the obtained granulated product was placed in an oven heated to 120°C and dried at normal pressure of 0.01 MPa for 140 minutes. Subsequently, the pressure in the oven was reduced, and the product was dried at a vacuum of -0.05 MPa for 140 minutes to obtain a granular solid product 7. As a result of the measurement by the above method, it was confirmed that the solid substance 7 contained water, HFC-365mfc, and PFBE.

[0089] [Example 8] When initially charging the polymerization vessel, 0.8 L of HFC-365mfc was replaced with CF ３ (CF ２ ) ４ CF ２0.8 L of ethanol (hereinafter also referred to as "CH") was added, and the amount of methanol was changed to 9.4 g, and the amount of PFBE was changed to 4.3 g. Furthermore, after heating and pressurizing by adding the TFE / E mixed gas, 6 mL of a 1 mass % solution of PBPV (solvent: CH) was pressure-fed into the polymerization vessel instead of the 1 mass % solution of PBPV (solvent: AE-3000). Furthermore, during polymerization, the amount of PFBE added was changed to 0.5 mL per 10 g of the added TFE / E mixed gas consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2, except for the above changes. Thereafter, the solvent was evaporated in the same manner as in Example 1, and the obtained solid was placed in an oven heated to 130°C and dried at normal pressure of 0.001 MPa for 90 minutes. Subsequently, the pressure in the oven was reduced, and the mixture was dried at a vacuum of -0.1 MPa for 60 minutes, thereby obtaining a granular solid 8. As a result of the measurement by the above method, it was confirmed that the solid substance 8 contained water, C6H, and PFBE.

[0090] [Example 9] A stainless steel polymerization vessel with an internal volume of 1.3 L and equipped with a stirrer and a jacket was evacuated, and then 0.8 L of CH, 3.9 g of methanol, and 14.2 g of the specific compound PFBE were charged. While stirring the mixture, a mixed gas of TFE and E with a TFE / E molar ratio of 88 / 12 (mol%) was added to pressurize the inside of the polymerization vessel to 1.5 MPaG, and the temperature inside the polymerization vessel was set to 66 ° C (polymerization temperature). After the temperature stabilized, 19 mL of a 1 mass % solution of PBPV (solvent: CH) was injected to initiate polymerization. During polymerization, a TFE / E mixed gas with a TFE / E molar ratio of 60 / 40 (mol%) was added to maintain a constant internal pressure of 1.5 MPaG. In addition, 1.4 mL of PFBE (corresponding to 1.4 mol % based on the total number of moles of TFE and E) was added every time 10 g of the TFE / E mixed gas added during the polymerization was consumed. When 100 g of the TFE / E mixed gas had been added, the polymerization vessel was cooled to terminate the polymerization, and a copolymer of TFE, ethylene, and PFBE was obtained.

[0091] Thereafter, residual monomer gas was purged from the polymerization vessel until the pressure inside the polymerization vessel reached 0.005 MPa (atmospheric pressure), and the slurry was transferred to a container with an internal volume of 2.6 L, followed by the addition of water at the same volume as the slurry. The slurry was heated with stirring to evaporate the solvent and produce (granulate) a granulated product containing the copolymer. During granulation, the interior of the container was heated within a range of 30 to 100°C. Granulation was terminated when it was visually confirmed that the volume of the mixture containing the granulated product inside the container had not decreased and remained constant, thereby obtaining a granulated product. The obtained granulated product was placed in an oven heated to 120°C and dried for 150 minutes under atmospheric pressure of 0.008 MPa, after which the oven was depressurized and the mixture was dried for 180 minutes under vacuum conditions of -0.05 MPa, yielding a granular solid product 9. Measurements using the above method confirmed that solid product 9 contained water, CH, and PFBE.

[0092] Example 10 When initially charging the polymerization vessel, 0.8 L of AE-3000 was added instead of 0.8 L of HFC-365mfc, and the amounts of methanol and PFBE were changed to 7.7 g and 9.6 g, respectively. Furthermore, the amount of a 1 mass % solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and pressurization by adding a TFE / E mixed gas was changed to 13 mL. Furthermore, during polymerization, the amount of PFBE added was changed to 1 mL for every 10 g of TFE / E mixed gas consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2, except for the above changes. Thereafter, the solvent was evaporated in the same manner as in Example 1, and the resulting solid was placed in an oven heated to 130°C and dried for 150 minutes under normal pressure of 0.01 MPa, and then the pressure inside the oven was reduced and the solid was dried for 180 minutes under vacuum conditions of -0.05 MPa to obtain a granular solid 10. As a result of measurement by the above method, it was confirmed that the solid 10 contained water, AE-3000, and PFBE.

[0093] [Example 11] A 1.3 L stainless steel polymerization vessel equipped with a stirrer and a jacket was evacuated, and then 0.8 L of AE-3000, 11.3 g of methanol, and a specific compound, CH ２ =CF(CF ２ ) ２ CF ２4.7 g of H (hereinafter also referred to as "C3olf") was charged. While stirring the mixture, a mixed gas of TFE and E having a TFE / E molar ratio of 86 / 14 (mol%) was added to pressurize the inside of the polymerization vessel to 1.5 MPaG, and the temperature inside the polymerization vessel was set to 72°C (polymerization temperature). After the temperature stabilized, 8 mL of a 1 mass% solution of PBPV (solvent: AE-3000) was injected to initiate polymerization. During the polymerization, a TFE / E mixed gas having a TFE / E molar ratio of 57 / 43 (mol%) was added so that the internal pressure was kept constant at 1.5 MPaG. In addition, 0.7 mL of C3olf (an amount equivalent to 1.6 mol% relative to the total number of moles of TFE and E) was added every time 10 g of the TFE / E mixed gas added during the polymerization was consumed. When 100 g of the TFE / E mixed gas was added, the polymerization vessel was cooled, polymerization was terminated, and a copolymer of TFE, ethylene, and PFBE was obtained. Thereafter, the solvent was evaporated in the same manner as in Example 1, and the resulting solid was placed in an oven heated to 130°C and dried for 85 minutes under normal pressure of 0.01 MPa. Subsequently, the pressure in the oven was reduced, and the solid was dried for 60 minutes under vacuum conditions of -0.09 MPa, to obtain a granular solid 11. As a result of measurement by the above method, it was confirmed that water, AE-3000, and C3olf were contained in the solid 11.

[0094] [Example 12] When initially charging the polymerization vessel, 4.7 g of the specific compound CH ２ =CH(CF ２ ) ５ CF ３(hereinafter also referred to as "C6olf") was added, and the amount of methanol was changed to 12.5 g. In addition, the amount of a 1 mass % solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization vessel after heating and adding the TFE / E mixed gas was changed to 7 mL. Furthermore, during the polymerization, 0.5 mL of C6olf (an amount corresponding to 1.4 mol % relative to the total number of moles of TFE and E) was added every time 10 g of the added TFE / E mixed gas was consumed. A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 11 except for the above changes. Thereafter, the solvent was evaporated in the same manner as in Example 1, and the obtained solid was placed in an oven heated to 130°C and dried at normal pressure of 0.01 MPa for 90 minutes. Subsequently, the pressure in the oven was reduced, and the mixture was dried at a vacuum of -0.09 MPa for 60 minutes to obtain a granular solid 12. As a result of the measurement by the above method, it was confirmed that the solid matter 12 contained water, AE-3000, and C6olf.

[0095] Example 13 A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 2. Thereafter, granules containing the copolymer were obtained in the same manner as in Example 1, and the obtained granules were placed in an oven heated to 120°C and dried under a vacuum condition of -0.05 MPa for 330 minutes to obtain a granular solid 13. Note that, as a result of measurement by the above method, it was confirmed that solid 13 contained water, HFC-365mfc, PFBE, and PPVE.

[0096] Example 14 A copolymer of TFE, ethylene, and PFBE was produced in the same manner as in Example 9. Thereafter, granules containing the copolymer were obtained in the same manner as in Example 1, and the obtained granules were placed in an oven heated to 120°C and dried under a vacuum condition of -0.05 MPa for 330 minutes to obtain a granular solid 14. Note that, as a result of measurement by the above method, it was confirmed that solid 14 contained water, HFC-365mfc, PFBE, and PPVE.

[0097] For the solids produced in each example, the MFR, composition, and melting point of the copolymer contained in the solid, as well as the content, proportion P, and specific surface area of ​​each component of the solid were measured by the above-mentioned methods. The measurement results are shown in Table 1 below.

[0098] The composition and physical properties of the copolymers obtained in each example, as well as the measurement and evaluation results of the solids, are shown in Table 1. In the table, the "TFE unit" column, the "E unit" column, and the "A unit" column indicate the content (unit: mol%) of each unit relative to the total units contained in the solids of each example.

[0099]

[0100] As shown in the table, it was confirmed that by using a solid material in which the ratio of the content of the specific compound to the total content of the solvent and the specific compound is 50.0 mass% or less, molded articles with excellent surface properties can be produced (Examples 1 to 12).

[0101] The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2023-221100, filed on December 27, 2023, are incorporated herein by reference as part of the disclosure of the present invention.

Claims

1. A copolymer comprising a unit based on tetrafluoroethylene, a unit based on ethylene, and a unit based on a specific compound selected from the group consisting of a compound represented by formula (1) and a compound represented by formula (2), the specific compound, and a solvent that is a compound different from the specific compound, wherein the ratio of the content of the specific compound to the total content of the solvent and the specific compound is 50.0% by mass or less, characterized by a solid. CX １ ２ =CX ２ (CF ２ ) ｍ X ３ (1) CF ２ =CF - O - (CF ２ ) ｎ F (2) In formula (1), X １ , X ２ and X ３ each independently represent a hydrogen atom or a fluorine atom, and m represents an integer from 1 to 6. In formula (2), n represents an integer from 1 to 6.

2. The solid according to claim 1, wherein the content of the unit based on tetrafluoroethylene is 48.00 to 64.90 mol% with respect to all the units contained in the copolymer.

3. The solid according to claim 1 or 2, wherein the content of the unit based on ethylene is 35.00 to 51.90 mol% with respect to all the units contained in the copolymer.

4. The solid according to claim 1 or 2, wherein the content of the unit based on the specific compound in the copolymer is 0.10 to 5.00 mol% with respect to all the units contained in the copolymer.

5. The solid according to claim 1 or 2, wherein the solvent contains a fluorine-containing solvent.

6. The solid according to claim 5, wherein the fluorine-containing solvent contains at least one selected from the group consisting of chlorofluorocarbon, perfluorocarbon, hydrofluorocarbon, and hydrofluoroether.

7. The solid according to claim 1 or 2, wherein the solvent contains water.

8. The solid according to claim 1 or 2, wherein the content of the solvent is 0.01 to 2% by mass with respect to the total mass of the solid.

9. The solid according to claim 1 or 2, having a specific surface area of 0.3 m ２ / g or more.

10. A composition comprising the solid according to claim 1 or 2 and at least one component selected from the group consisting of other resins, heat stabilizers, antioxidants, colorants, ultraviolet absorbers, fillers, crosslinking agents, crosslinking aids, and organic peroxides other than the copolymer.

11. A molded article, characterized in that it is obtained by molding the solid according to claim 1 or 2.

12. A molded article, characterized in that it is obtained by molding the composition according to claim 10.

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