WO2025142865A1 - Solid material, composition, and molded body - Google Patents

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

The present invention relates to a solid object, a composition and a molded body.

Ethylene/tetrafluoroethylene copolymer (hereinafter also referred to as "ETFE") is excellent in heat resistance, weather resistance, electrical insulation, non-adhesiveness, water repellency, oil repellency, etc., and is characterized by high moldability and mechanical strength among fluororesins. Therefore, a variety of molded products such as electric wire coverings, tubes, sheets, films, filaments, pump casings, joints, packings, linings, coatings, etc. are manufactured 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, comprising the steps of: producing a wet copolymer by suspension polymerization, solution polymerization or bulk polymerization in the presence of a predetermined fluorinated ether; heating the wet copolymer in a vessel to vaporize and discharge a vaporized substance containing the fluorinated ether; and transferring the vaporized substance to a cooling means and cooling it.

Patent No. 5569660

When ETFE is used as a constituent material of a molded article, it is required that it is excellent in various performances, specifically, it is required that a molded article having excellent surface properties can be produced.
The present inventors produced ETFE with reference to the method described in the above Patent Document 1, and evaluated a molded article formed using the produced ETFE, and found that there was room for improvement in the surface properties of the obtained molded article.

The present invention therefore aims to provide a solid material that can form a molded body with excellent surface properties. It also aims to provide a composition that contains the solid material, a molded body obtained by molding the solid material, and a molded body obtained by molding the composition.

As a result of intensive research into the above-mentioned problems, the present inventors discovered that a molded body with excellent surface properties can be formed by using a solid material that contains 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, and 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, and thus arrived at the present invention.

That is, the inventors discovered that the above problems can be solved by the following configuration.
[1]
A solid comprising: a copolymer including 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) described below and a compound represented by formula (2) described below; the specific compound; and a solvent which 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 material according to [1], wherein the content of the units based on the tetrafluoroethylene is 48.00 to 64.90 mol % based on all units contained in the copolymer.
[3]
The solid material 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 material according to any one of [1] to [3], wherein the content of the unit 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 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 contains at least one selected from the group consisting of chlorofluorocarbons, perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers.
[7]
The solid according to any one of [1] to [6], wherein the solvent contains water.
[8]
The solid according to any one of [1] to [7], wherein the content of the solvent is 0.01 to 2 mass% based on the total mass of the solid.
[9]
The solid matter according to any one of [1] to [8], which has a specific surface area of 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 assistant, and an organic peroxide.
[11]
A molded article, which is obtained by molding the solid material according to any one of [1] to [10].
[12]
A molded article obtained by molding the composition according to [10].

The present invention can provide a solid material capable of forming a molded article having excellent surface properties. The present invention can also 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.

The terms used in this specification have the following meanings:
A numerical range expressed using "to" means a range including the numerical values described before and after "to" as the lower and upper 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. In addition, 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 the present specification, each component may be used alone or in combination of two or more substances corresponding to each component. When two or more substances are used in combination for each component, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.
As used herein, a combination of two or more preferred aspects is a more preferred aspect.

The term "unit" refers collectively to an atomic group derived from one molecule of the above-mentioned monomer that is formed directly by polymerization of the monomer, and an atomic group obtained by chemically converting a part of the above-mentioned atomic group. In the following, in some cases, a unit derived from an individual monomer will be referred to by the name of the monomer with "unit" added.
The "TFE unit" is a unit based on tetrafluoroethylene in the copolymer, the "E unit" is a unit based on ethylene in the copolymer, and the "A unit" is a unit based on a specific compound described below.
"Solvent" means a substance that is liquid at 25°C and 1013 hPa.

[Solid object]
The solid of the present invention (hereinafter also referred to as "the present solid") contains a copolymer containing TFE units, E units, and A units based on a specific compound described below, and further contains the specific compound and a solvent which is a compound different from the specific compound.
The solid is also 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.

By using this solid, a molded product with excellent surface properties can be formed. Although the details of the reason for this have not yet been clarified, it is believed that the content of the specific compound in the components used in the production of the copolymer or solid product in this solid product is equal to or less than a predetermined value. It is believed that the specific compound is likely to remain in the solid product because of its relatively high lipophilicity, and if the solid product contains more specific compounds than the solvent, it is presumed that bubbles originating from the specific compounds will be generated by heating during molding when the solid product 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, in the present solid, the content of the specific compound relative to the total content of the solvent and the specific compound is equal to or less than a predetermined value, so that it is presumed that the specific compound is less likely to remain in the solid, and as a result, bubbles are less likely to be generated during molding, and the number of voids formed on the surface of the molded body is reduced, resulting in better surface properties of the molded body.
Here, a molded product having excellent surface properties means a molded product in which the generation of voids (air bubbles) caused by a specific compound is suppressed on the surface of the molded product.

The components contained in this solid are explained below.

[Copolymer]
The solid comprises a copolymer comprising 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.

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).

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 represent a hydrogen atom or a fluorine atom; m represents an integer of 1 to 6.
In formula (2), n represents an integer of 1 to 6.

In the compound represented by formula (1), X ¹ is preferably a hydrogen atom from the viewpoint of polymerizability.
From the viewpoint of polymerizability, ^X2 is preferably a hydrogen atom.
^X3 is preferably a fluorine atom.
m is preferably an integer of 2 to 6, more preferably an integer of 3 to 6, and further preferably 3 or 4.

Examples of the compound represented by formula (1) include _CH2 =CH( _CF2 ) _2F , _CH2 =CH( _CF2 ) _4F (hereinafter also referred to as "PFBE"), _CH2 =CH( _CF2 ) _6F , _CH2 =CF( _{CF2)3F, and CH2=CF(CF2 ) 4F ,} with PFBE, _CH2 =CH( _CF2 ) _6F , _{and CH2} =CF( _CF2 ) _3F being preferred, and PFBE being more preferred.

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 F. Among these, CF ₂ ═CF-O-(CF ₂ ) ₃ F, which corresponds to the compound in which n is 3, is preferred.

The copolymer may contain, as A units, either a unit based on a compound represented by formula (1) (hereinafter also referred to as "A1 units") or a unit based on a compound represented by formula (2) (hereinafter also referred to as "A2 units"), or may contain both A1 units and A2 units.
That is, when the copolymer contains both A1 units and A2 units, the "content of A units" means the total content of A1 units and the content of A2 units.

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 in terms of excellent long-term folding resistance.

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 it is equal to or greater than the lower limit, the heat resistance of the molded article will be superior, and if it is equal to or less than the upper limit, the mechanical properties of the molded article will be superior.

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 it 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.

The content of A units is preferably 0.01 to 10.0 mol % of all units contained in the copolymer, more preferably 0.10 to 5.00 mol %, and even more preferably 0.50 to 4.00 mol %. If it is equal to or greater than the lower limit, a molded product with excellent abrasion resistance can be formed, and if it is equal to or less than the upper limit, a molded product with excellent dimensional stability can be formed.

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.

The copolymer may contain units based on other monomers than tetrafluoroethylene, ethylene and the specific compound.
Specific examples of other monomers include fluoroolefins (e.g., vinyl fluoride, vinylidene fluoride, trifluoroethylene, hexafluoroisobutylene, etc., excluding specific compounds), CF ₂ ═CFORf ¹ SO ₂ Y ¹ (wherein 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 (wherein 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), and CF ₂ ═CF(CF ₂ )pOCF═CF ₂ (wherein 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) etc.), itaconic acid, itaconic anhydride, citraconic acid and citraconic anhydride. Among these, itaconic acid, itaconic anhydride, citraconic acid or citraconic anhydride is preferred, and itaconic anhydride is more preferred.

If 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 the total units contained in the copolymer.

The copolymer is preferably one comprising TFE units, E units and A units, and more preferably one comprising TFE units, E units and A1 units.
The content of the copolymer in the 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 of superior crushability of the solid. The content of the copolymer in the solid is preferably 99.99% by mass or less, from the viewpoint of superior bending resistance of the molded article.

<Melt flow rate>
The melt flow rate (hereinafter, also referred to as "MFR") of the copolymer is preferably from 1 to 60 g/10 min, and more preferably from 2 to 50 g/10 min.
When the MFR of the copolymer is equal to or higher than the lower limit, a molded article having excellent fluidity during melt molding can be formed, whereas when the MFR of the copolymer is equal to or lower than the upper limit, a molded article having excellent abrasion resistance at high temperatures can be formed.
A specific example of a method for controlling 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 a copolymer is obtained by measuring the mass of a solid matter 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 D3159. Since the copolymer is the main component of the solid matter and components other than the copolymer have almost no effect on the measurement of MFR, the measured MFR value obtained by measuring the solid matter can be regarded as the MFR of the copolymer.

<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, from the viewpoint of excellent moldability of the solid product.
Specific examples of the method for adjusting the melting point of the copolymer within the above range include a method of lowering the polymerization temperature during the production of the copolymer, and a method of adjusting the content of A units in the copolymer.
The melting point of the copolymer is a temperature corresponding to an endothermic peak detected when a solid object is heated at a rate of 10° C./min in an air atmosphere using a differential scanning calorimeter. As with the MFR, the measured value of the melting point obtained by measuring the solid object can be regarded as the melting point of the copolymer.

[Specific compound]
The 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.

The specific compound contained in the present solid matter 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, it is preferable that the specific compound from which the A units contained in the copolymer are derived is the same as the specific compound contained in the solid. For example, when the copolymer contains PFBE units as the A units, it is preferable that the solid contains PFBE as the specific compound.

The content of the specific compound contained in the present solid 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, in terms of better surface properties of the molded article.
The content of the specific compound contained in the present solid is preferably 0.0001% by mass or more, and more preferably 0.001% by mass or more, in order to provide a molded article with better bending resistance.

The content of specific compounds and solvents (described below, excluding water) 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.

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

The solid preferably contains a fluorine-containing solvent as a solvent. By fluorine-containing solvent is meant an organic solvent containing at least one fluorine atom.
Examples of fluorine-containing solvents include chlorofluorocarbons, perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers.
The fluorine-containing solvent preferably has 2 to 7 carbon atoms, and more preferably has 2 to 6 carbon atoms.
The 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.

Hydrofluorocarbons are fluorine-containing solvents that consist of hydrogen atoms, fluorine atoms and carbon atoms and contain no heteroatoms other than fluorine atoms.
The hydrofluorocarbon preferably has 3 to 7 carbon atoms, and more preferably has 4 to 6 carbon atoms.
The hydrofluoroether preferably contains one ether bond.

_{Specific examples of hydrofluorocarbons} include _{CF3CFHCF2CF2CF3 ,} CF3( _{CF2 ) 4H , CF3CF2CFHCF2CF3} , CF3CFHCFHCF2CF3 _{, CF2HCFHCF2CF2CF3} , CF3 _{( CF2} ) _{5H , CF3CH ( CF3 ) CF2CF2CF3 , CF3CF ( CF3 ) CFHCF2CF3 , CF3CH ( CF3 ) CFHCF2CF3 , CF3CF2CH2CH3 , and CF3 Examples of such compounds include (CF2)3CH2CH3 , 1,1,2,2 - tetrafluorocyclobutane , CF3CFHCFHCF3 , CF3CF} ( _CF3 ) _CFHCFHCF3 , _CF3CH2CF2CH3 , _{CF2ClCFCl2 , CF2ClCCl2F} , _{and CF3CClFCFCClCF3 .}
Of these, CF ₃ (CF ₂ ) ₅ H or CF ₃ CH ₂ CF ₂ CH ₃ is preferred.

Hydrofluoroether is a fluorine-containing solvent that has an ether bond and contains hydrogen atoms and fluorine atoms.
The hydrofluoroether preferably has 3 to 7 carbon atoms, more preferably 4 to 6 carbon atoms, and even more preferably 4 or 5 carbon atoms.
The hydrofluoroether preferably contains one ether bond.

Specific examples of hydrofluoroethers include _{CF3CH2OCF2CF2H} , CF3 _{( CF3 ) CFCF2OCH3} , _CF3 ( _CF2 ) _{3OCH3 , CF3 ( CF2 ) 3OC2H5 , CF3 ( CF2 ) 2C3F7OCH3} , _and ( _{CF3 ) 2CFOCH3 , with CF3CH2OCF2CF2H being preferred .}

If the solid contains a fluorine-containing solvent, the content of the fluorine-containing solvent is preferably 0.0001 to 0.5 mass %, and more preferably 0.0001 to 0.4 mass %, based on the total mass of the solid.

In the present solid matter, the solvent preferably contains water.
When the solid contains water, the handling properties during transportation are superior.

When the present solid contains water, the content of water is preferably 0.01 to 0.5 mass %, more preferably 0.01 to 0.2 mass %, based on the total mass of the solid.
The water content in the solid material is calculated from the difference between the weight loss of the solid material measured by a thermogravimetric and differential thermal analyzer and the total content of the solvent and the specific compound in the solid material measured by a headspace GC/MS device. A more detailed measurement method is described in the examples below.

<Ratio P>
As described above, in this solid, the 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)), is 50.0 mass% or less.
The proportion P is preferably from 0.1 to 50.0 mass %, more preferably from 0.5 to 50.0 mass %.
If it is equal to or less than the upper limit, a molded product having better surface properties can be formed, whereas if it is equal to or more than the lower limit, the cohesiveness of the solid matter is reduced and the flowability is better.

In this solid, 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.

The solid may be in the form of, for example, granules (beads), pellets, threads, etc.

[Specific surface area]
The specific surface area of the solid is preferably 0.3 m ² /g or more, more preferably 0.5 m ² /g or more, even more preferably 5 m ² /g or more, particularly preferably 10 m ² /g or more, and is preferably 40 m ² /g or less, more preferably 30 m ² /g or less.
When the specific surface area of the solid matter is equal to or greater than the above lower limit, a molded product having more excellent surface properties can be formed.

The specific surface area of a solid is the BET specific surface area (unit: ^m2 /g) per mass of the solid measured by the BET method based on the amount of nitrogen adsorbed on the surface of the solid. The specific surface area of a solid can be measured using a known specific surface area measuring device (e.g., Microtrack-Bell, product 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.

[Method for producing solid objects]
This solid can be produced, for example, by a production method in which the above-mentioned monomers (tetrafluoroethylene, ethylene and the specific compound) are polymerized in a polymerization solvent to produce a copolymer, a mixture containing the copolymer, the polymerization solvent and water is heated with stirring to granulate the copolymer, and the resulting granules are dried, and the granules are dried in two stages: a first stage in which the granules are dried under normal pressure conditions, and a second stage in which the granules are dried under vacuum conditions.
The above method, which is an example of the method for producing the present solid material, will be described below.

<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, it is preferably produced by solution polymerization.
In the production of the copolymer, in addition to the above-mentioned monomers and polymerization solvent, a polymerization initiator, a chain transfer agent, etc. can be used.

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 kinds.
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, based on 100 parts by mass of the monomer used.

As the polymerization solvent, a fluorine-containing solvent such as a hydrofluorocarbon, a hydrofluoroether, a perfluorocarbon, or a chlorofluorocarbon can be used.
The polymerization solvent may be used alone or in combination of two or more kinds.
As the polymerization solvent, it is preferable to use a fluorine-containing solvent, more preferably a hydrofluorocarbon, a hydrofluoroether, a perfluorocarbon or a chlorofluorocarbon, and further preferably a hydrofluorocarbon or a 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, and is preferably 20 times or less, more preferably 17 times or less.

In preparing the copolymer, a chain transfer agent may be used, and the use of a chain transfer agent is preferred.
As the chain transfer agent, from the viewpoint of a large chain transfer constant and a small amount to be added, preferred are alcohols such as methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoropropanol, 1,1,1,3,3,3-hexafluoroisopropanol, 2,2,3,3,3-pentafluoropropanol, etc.; hydrofluorocarbons such as CF ₂ H ₂ , etc.; hydrocarbons such as n-pentane, n-hexane, cyclohexane, etc.; ketones such as acetone, etc.; mercaptans such as methyl mercaptan, etc.; esters such as methyl acetate, ethyl acetate, etc.; ethers such as diethyl ether, methyl ethyl ether, etc.
Among them, at least one selected from the group consisting of alcohols, hydrocarbons and hydrofluorocarbons is preferred from the viewpoint of higher chain transfer constant and higher stability of the end group of the copolymer, at least one selected from the group consisting of alcohols and hydrocarbons is more preferred, and alcohols are even more preferred. Among the alcohols, methanol or ethanol is particularly preferred. Among them, methanol is most preferred from the viewpoint of reactivity and availability. Two or more chain transfer agents may be used.
The amount of the chain transfer agent used is preferably 0.001 times or more, more preferably 0.005 times or more, based on the amount of the monomer used, in terms of mass ratio, and is preferably 5 times or less, more preferably 4 times or less.

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 from 0.5 to 3.0 MPa, particularly preferably from 0.9 to 2.5 MPa.
The polymerization time is preferably from 1 to 12 hours.

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

In the granulation, first, a mixture containing the copolymer, a polymerization solvent, and water is prepared. The mixture can be prepared, for example, by mixing a slurry containing the copolymer and the polymerization solvent with water.
In preparing the mixture, the slurry obtained after the production of the copolymer may be used as it is, or a concentrated slurry or a diluted slurry obtained by adding a dilution solvent to the slurry 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 the granulation may be 20 to 500% by volume, more preferably 50 to 300% by volume, based on the total amount of the copolymer and the polymerization solvent.

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) other than the polymerization tank and mixing the slurry with water. It is preferable to transfer the slurry containing the copolymer and the polymerization solvent from the polymerization tank to a granulation tank in which water has been added in advance and mix them.
The granulation tank may be a sealable container equipped with an impeller for stirring the contents, a heating means for heating the container or the contents, and an exhaust means for exhausting the separated gas. The impeller may be a commonly used impeller such as a turbine impeller or an anchor impeller. Examples of the heating means include a jacket, a hot water bath, an oil bath, and steam heating.

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 pressures described in this specification are gauge pressures based on atmospheric pressure.
The granulation time may be, for example, 1 to 24 hours, preferably 1 to 15 hours.
The timing for granulation to end may be, for example, when the volume of the mixture contained in the granulation tank does not decrease for a certain period of time. When it is confirmed that the volume of the mixture in the granulation tank has not decreased and has become constant for a certain period of time, it can be assumed that most of the components such as the solvent discharged from the granulation tank during the above granulation have been discharged.

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

From the viewpoint of producing a solid material having a low ratio P, it is preferable to produce a solid material containing a copolymer by drying the granulated material containing the copolymer in two stages, namely, a first stage in which the granulated material is dried under normal pressure conditions, and a second stage in which the granulated material is dried under vacuum conditions.
Here, normal pressure conditions means that the pressure inside the container in which the drying process is performed is 0 to 0.1 MPa, and vacuum conditions means that the pressure inside the container in which the drying process is performed is -0.01 to -0.1 MPa.

The granulated material obtained by the above granulation contains moisture, polymerization solvent, and specific compounds (hereinafter collectively referred to as "vaporized substances"). In the subsequent drying process, these components vaporize, producing a solid material having pores on the surface. According to the inventors' research, it has been found that if the granulated material obtained by granulation is not dried under normal pressure conditions but is dried only under vacuum conditions, a solid material with a small specific surface area is obtained. From this, it is presumed that if the granulated material is dried only under vacuum conditions, the vaporized substances vaporize rapidly near the surface, while the size of the pores formed near the surface becomes small, making it easier for the vaporized substances (especially the specific compounds) to remain inside the solid material. On the other hand, it has been found that if the granulated material obtained by granulation is dried in two stages, first under normal pressure conditions and then under vacuum conditions, a solid material with a large specific surface area is obtained. From this, it is presumed that when the above two-stage drying is performed, 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.

A specific example of a drying method includes a method in which the granulated material is transferred from a granulation vessel to a drying vessel such as a dryer, and the granulated material is heated under a specified pressure condition to vaporize and separate the vaporized substances contained in the granulated material.
Examples of the dryer used for drying include a batch type rotary dryer, an indirect heating type dryer, a vacuum dryer, and a hot air dryer.

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 in the range of 35 to 130°C.
The drying time in the first stage is preferably from 1 to 24 hours, more preferably from 1 to 12 hours.

The pressure inside the vessel during the second stage drying is preferably −0.01 to −0.1 MPa, and 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 in the range of 60 to 150°C.
The drying time in the second stage is preferably from 1 to 24 hours, more preferably from 1 to 12 hours.

Furthermore, it is preferable that the drying time for the first stage be 30-70% of the total drying time, and the drying time for the second stage be 70-30%, and it is even more preferable that the drying time for the first stage be 30-60% and the drying time for the second stage be 40-70%.

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

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

The content of the above "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.

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, which are used as necessary, by a known method.
The solid can be pulverized using a known pulverizer such as a rotor mill, a hammer mill, a turbo mill, or a jet mill.

[Molded body]
The molded article of the present invention is obtained by molding the present solid or the present composition. Since 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 properties are excellent.
Specific examples of molding methods include injection molding, extrusion molding, blow molding, press molding, rotational molding, electrostatic painting, and spray molding.

The molded article of the present invention may be a coating film formed using the present solid or the present composition. The coating film may be formed by pulverizing the present solid to obtain a powder or by using the present composition containing the powder, and forming the coating film by rotational molding, electrostatic coating, or spray molding.
The thickness of the coating film is preferably from 1 μm to 10 mm, more preferably from 50 μm to 5 mm, and even more preferably from 100 μm to 3 mm.

Specific examples of molded articles 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.

The present solid, the present composition or the above-mentioned molded article can be used for the following purposes.
Food packaging films, lining materials for fluid transfer lines used in food manufacturing processes, packing materials, sealing materials, and fluid transfer components for food manufacturing equipment such as sheets;
Drug stoppers, packaging films, lining materials for fluid transfer lines used in drug manufacturing processes, packing materials, sealing materials, and drug transfer components such as sheets;
Inner lining components for chemical tanks and piping in chemical plants or semiconductor factories;
Fuel transfer components such as O-rings, tubes, packing, valve core materials, hoses, and seals used in automobile fuel systems and peripheral devices, as well as hoses and seals used in automobile AT devices;
Carburetor flange gaskets, shaft seals, valve stem seals, sealing materials, hoses, etc. used in automobile engines and peripheral devices, as well as other automobile parts such as automobile brake hoses, air conditioner hoses, radiator hoses, and electric wire covering materials;
Chemical liquid transfer components for semiconductor manufacturing equipment, such as O-rings, tubes, packing, valve core materials, hoses, seal materials, rolls, gaskets, diaphragms, and joints;
Paint and ink components such as paint rolls, hoses, tubes, and ink containers for painting equipment;
Tubes for food and beverages, hoses for food and beverages, and other tubes, hoses, belts, packings, and food and beverage transport components such as joints, food packaging materials, and glass cooking equipment;
Waste liquid transport components such as tubes and hoses for transporting waste liquid;
Components for transporting high-temperature liquids, such as tubes and hoses for transporting high-temperature liquids;
Steam piping components such as steam piping tubes and hoses;
Anticorrosive 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, transparent front coating materials and back coating materials provided on the light incident surface of photovoltaic elements of solar cells;
Sliding members such as diaphragms of diaphragm pumps and various packings;
Agricultural films and weather-resistant coverings for various roofing materials and sidewalls;
Interior materials used in the building industry, and glass covering materials such as non-combustible fire-resistant safety glass;
Lining materials such as laminated steel sheets used in the home appliance sector, etc.;
Carrier film for fuel cells.
Among these, the molded article of the present invention is particularly suitable for use as a chemical solution transporting member or coating material for semiconductor device because of its excellent surface properties.

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.
The various measurement and evaluation methods are as follows.

[measurement]
<Content of solvents and specific compounds in solids>
The contents of the solvent and specific compounds remaining in the solid were 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 by a thermogravimetry-differential thermal analyzer (TG-DTA) and the total content of the solvent and specific compound in the solid measured by 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 temperature increase rate of 10° C./min using the TG-DTA and measuring the weight of the solid before and after heating.

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

<MFR (Melt Flow Rate)>
Using a melt indexer (manufactured by Technoseven Co., Ltd.), the mass (g) of solid matter flowing out from 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 measured value was regarded as the MFR (g/10 min) of the copolymer.

<Melting Point>
The melting point (°C) of the copolymer was determined from an endothermic peak detected when a solid material 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).

<Specific surface area>
The specific surface area of the solid material was measured based on the amount of nitrogen adsorbed on the particle surface of the solid material by the BET method using a BET specific surface area measuring device (manufactured by Microtrac-Bel, product name "BELSORP MINI X").
From the measured specific surface area values, the specific surface area of the solid matter of each example was evaluated according to the following criteria.
(Evaluation Criteria)
⊚: The measured 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 and less than 20 m ² /g.
Δ: The measured value of the specific surface area is 0.3 m ² /g or more and less than 10 m ² /g.
×: The measured specific surface area is less than 0.3 m ² /g.

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

[Example 1]
A stainless steel polymerization tank with an inner volume of 1.3 L (liters) and equipped with a stirrer and a jacket was evacuated, and then 0.8 L of CF ₃ CH ₂ CF ₂ CH ₃ (hereinafter also referred to as "HFC-365mfc"), 8.7 g of methanol, and 12.1 g of specific compounds CH ₂ ═CH(CF ₂ ) ₄ F (PFBE) and 0.4 g of CF ₂ ═CFO(CF ₂ ) ₂ CF ₃ (hereinafter also referred to as "PPVE") were charged. While stirring the mixture, a mixed gas of tetrafluoroethylene (TFE) and E with a molar ratio of TFE/ethylene (E) of 83/17 (mol%) was added to pressurize the inside of the polymerization tank to 1.5 MPaG (gauge pressure), and the temperature inside the polymerization tank was set to 72° C. (polymerization temperature). After the temperature became stable, 17 mL of a 1% by mass solution of tert-butyl peroxypivalate (hereinafter also referred to as "PBPV") (solvent: CF ₃ CH ₂ OCF ₂ CF ₂ H (hereinafter also referred to as "AE-3000")) was injected to initiate polymerization.
During polymerization, TFE/E mixed gas with 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 (corresponding to 3.1 mol% relative to the total number of moles of TFE and E) was added every time 10 g of TFE/E mixed gas added during polymerization was consumed. When 100 g of TFE/E mixed gas was added, the polymerization tank was cooled, polymerization was terminated, and a copolymer of TFE, ethylene, PFBE, and PPVE was obtained.

Thereafter, the residual monomer gas was purged from the polymerization tank until the pressure in the polymerization tank reached 0.01 MPa, and the slurry was transferred to a container with an internal volume of 2.6 L, and water of the same volume as the slurry was added. The slurry was heated while being stirred to evaporate the solvent and produce a granulated material containing the copolymer (granulation). During granulation, the inside of the container was heated in the range of 30 to 100°C. Granulation was terminated when it was visually confirmed that the content of the mixture containing the granulated material in the container did not decrease and became constant, and a granulated material was obtained. The obtained granulated material was placed in an oven heated to 120°C and dried for 90 minutes under normal pressure conditions of 0.01 MPa, and then the pressure in the oven was reduced and the mixture was dried for 60 minutes under vacuum conditions of -0.07 MPa to obtain a granular solid material 1.
As a result of the measurement by the above method, it was confirmed that solid substance 1 contained water, HFC-365mfc, PFBE and PPVE.

[Example 2]
When initially charging the polymerization tank, the amount of methanol was changed to 10.6 g, the amount of PFBE was changed to 9.6 g, and PPVE was not charged to the polymerization tank. In addition, the amount of 1 mass% solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization tank after heating and pressurization by adding TFE/E mixed gas was changed to 13 mL. Furthermore, the amount of PFBE to be added during polymerization was changed to 1.0 mL 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 1 except for the above changes.
Thereafter, a granulated material containing a copolymer was obtained in the same manner as in Example 1, and the obtained granulated material was placed in an oven heated to 120° C. and dried for 150 minutes under normal pressure of 0.01 MPa. Subsequently, the pressure in the oven was reduced, and the material was dried for 180 minutes under vacuum conditions of −0.05 MPa, thereby obtaining a granular solid material 2.
As a result of the measurement by the above method, it was confirmed that the solid matter 2 contained water, HFC-365mfc, and PFBE.

[Example 3]
When initially charging the polymerization tank, 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 1 mass% solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization tank after heating and pressurization by adding TFE/E mixed gas was changed to 5 mL. Furthermore, the amount of PFBE to be added during polymerization was changed to 0.4 mL 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 material containing a copolymer was obtained in the same manner as in Example 1, and the obtained granulated material was placed in an oven heated to 120° C. and dried for 180 minutes under normal pressure of 0.01 MPa. Subsequently, the pressure in the oven was reduced, and the material was dried for 240 minutes under vacuum conditions of −0.09 MPa, thereby obtaining a granular solid material 3.
As a result of the measurement by the above method, it was confirmed that the solid matter 3 contained water, HFC-365mfc, and PFBE.

[Example 4]
When initially charging the polymerization tank, 0.8 L of 2,3-dichlorooctafluorobutane was added instead of 0.8 L of HFC-365mfc, and the amount of methanol was changed to 20.8 g and the amount of PFBE was changed to 5.9 g. In addition, the amount of 1 mass % solution of PBPV (solvent: AE-3000) to be pressed into the polymerization tank after heating and pressurization by adding TFE/E mixed gas was changed to 5 mL. Furthermore, during polymerization, the amount of PFBE added was increased to 0.4 mL 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 material containing a copolymer was obtained in the same manner as in Example 1, and the obtained granulated material was placed in an oven heated to 120°C and dried for 95 minutes under normal pressure of 0.01 MPa. Subsequently, the pressure in the oven was reduced, and the material was dried for 85 minutes under vacuum conditions of -0.09 MPa, thereby obtaining a granular solid material 4.
As a result of the measurement by the above method, it was confirmed that the solid matter 4 contained water, 2,3-dichlorooctafluorobutane, and PFBE.

[Example 5]
When initially charging the polymerization tank, 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 1 mass% solution of PBPV (solvent: AE-3000) to be pressed into the polymerization tank after heating and pressurization by adding TFE/E mixed gas was changed to 9 mL. Furthermore, the amount of PFBE to be added during polymerization was changed to 0.7 mL 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 material containing a copolymer was obtained in the same manner as in Example 1, and the obtained granulated material was placed in an oven heated to 120° C. and dried for 85 minutes under normal pressure of 0.01 MPa. Subsequently, the pressure in the oven was reduced, and the material was dried for 120 minutes under vacuum conditions of −0.07 MPa, thereby obtaining a granular solid material 5.
As a result of the measurement by the above method, it was confirmed that the solid matter 5 contained water, HFC-365mfc, and PFBE.

[Example 6]
When initially charging the polymerization tank, 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 1 mass% solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization tank after heating and pressurization by adding TFE/E mixed gas was changed to 10 mL. Furthermore, the amount of PFBE to be added during polymerization was changed to 0.8 mL 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 material containing a copolymer was obtained in the same manner as in Example 1, and the obtained granulated material was placed in an oven heated to 120°C and dried for 150 minutes under normal pressure of 0.01 MPa. Subsequently, the pressure in the oven was reduced, and the material was dried for 180 minutes under vacuum conditions of -0.05 MPa, thereby obtaining a granular solid material 6.
As a result of the measurement by the above method, it was confirmed that the solid matter 6 contained water, HFC-365mfc, and PFBE.

[Example 7]
When initially charging the polymerization tank, 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 1 mass% solution of PBPV (solvent: AE-3000) to be pressurized into the polymerization tank after heating and pressurization by adding TFE/E mixed gas was changed to 8 mL. Furthermore, the amount of PFBE to be added during polymerization was changed to 0.7 mL 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 material containing a copolymer was obtained in the same manner as in Example 1, and the obtained granulated material was placed in an oven heated to 120°C and dried for 140 minutes under normal pressure conditions of 0.01 MPa. Subsequently, the pressure in the oven was reduced, and the material was dried for 140 minutes under vacuum conditions of -0.05 MPa, thereby obtaining a granular solid material 7.
As a result of the measurement by the above method, it was confirmed that the solid matter 7 contained water, HFC-365mfc, and PFBE.

[Example 8]
When initially charging the polymerization tank, 0.8 L of CF ₃ (CF ₂ ) ₄ CF ₂ H (hereinafter also referred to as "C6H") was added instead of 0.8 L of HFC-365mfc, and the amount of methanol was changed to 9.4 g and the amount of PFBE was changed to 4.3 g. In addition, 6 mL of a 1 mass % solution of PBPV (solvent: C6H) was pressed into the polymerization tank after heating and pressurization by adding TFE/E mixed gas instead of a 1 mass % solution of PBPV (solvent: AE-3000). Furthermore, during polymerization, the amount of PFBE added every time 10 g of the added TFE/E mixed gas was consumed was changed to 0.5 mL. 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 for 90 minutes under normal pressure conditions of 0.001 MPa. Subsequently, the pressure in the oven was reduced, and the solid was dried for 60 minutes under vacuum conditions of −0.1 MPa, thereby obtaining a granular solid 8.
As a result of the measurement by the above method, it was confirmed that the solid matter 8 contained water, C6H, and PFBE.

[Example 9]
After evacuating a stainless steel polymerization tank with an inner volume of 1.3 L and equipped with a stirrer and a jacket, 0.8 L of CH, 3.9 g of methanol, and 14.2 g of PFBE, a specific compound, 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 tank to 1.5 MPaG, and the temperature inside the polymerization tank was set to 66°C (polymerization temperature). After the temperature was stabilized, 19 mL of a 1% by mass solution of PBPV (solvent: CH) was injected to start polymerization.
During polymerization, TFE/E mixed gas with a molar ratio of TFE/E of 60/40 (mol%) was added so that the internal pressure was constant at 1.5 MPaG. In addition, 1.4 mL of PFBE (corresponding to 1.4 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 polymerization was consumed. When 100 g of the TFE/E mixed gas was added, the polymerization tank was cooled, the polymerization was terminated, and a copolymer of TFE, ethylene, and PFBE was obtained.

Thereafter, the residual monomer gas was purged from the polymerization tank until the pressure in the polymerization tank reached 0.005 MPa (normal pressure), the slurry was transferred to a container with an internal volume of 2.6 L, and water of the same volume as the slurry was added. The slurry was heated while stirring to evaporate the solvent and produce a granulated material containing the copolymer (granulation). During granulation, the inside of the container was heated in the range of 30 to 100°C. Granulation was terminated when it was visually confirmed that the content of the mixture containing the granulated material in the container did not decrease and became constant, and a granulated material was obtained. The obtained granulated material was placed in an oven heated to 120°C and dried for 150 minutes under normal pressure conditions of 0.008 MPa, and then the pressure in the oven was reduced and the mixture was dried for 180 minutes under vacuum conditions of -0.05 MPa to obtain a granular solid material 9.
As a result of the measurement by the above method, it was confirmed that the solid matter 9 contained water, C6H, and PFBE.

[Example 10]
When initially charging the polymerization tank, 0.8 L of AE-3000 was added instead of 0.8 L of HFC-365mfc, and the amount of methanol was changed to 7.7 g and the amount of PFBE was changed to 9.6 g. In addition, the amount of 1 mass% solution of PBPV (solvent: AE-3000) to be pressed into the polymerization tank after heating and pressurization by adding TFE/E mixed gas was changed to 13 mL. Furthermore, the amount of PFBE to be added during polymerization was changed to 1 mL 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, 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 for 150 minutes under normal pressure conditions of 0.01 MPa. Subsequently, the pressure in 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 the measurement by the above method, it was confirmed that the solid object 10 contained water, AE-3000, and PFBE.

[Example 11]
A stainless steel polymerization tank with an internal volume of 1.3 L and equipped with a stirrer and a jacket was evacuated, and then 0.8 L of AE-3000, 11.3 g of methanol, and 4.7 g of a specific compound, CH ₂ ═CF(CF ₂ ) ₂ CF ₂ H (hereinafter also referred to as "C3olf"), were charged. While stirring the mixture, a mixed gas of TFE and E with a TFE/E molar ratio of 86/14 (mol%) was added to pressurize the inside of the polymerization tank to 1.5 MPaG, and the temperature inside the polymerization tank was set to 72° C. (polymerization temperature). After the temperature was stabilized, 8 mL of a 1% by mass solution of PBPV (solvent: AE-3000) was injected to initiate polymerization.
During polymerization, TFE/E mixed gas with a molar ratio of TFE/E of 57/43 (mol%) was added so that the internal pressure was constant at 1.5 MPaG. In addition, 0.7 mL of C3olf (corresponding 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 polymerization was consumed. When 100 g of the TFE/E mixed gas was added, the polymerization tank was cooled, the 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 obtained solid was placed in an oven heated to 130° C. and dried for 85 minutes under normal pressure conditions 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, thereby obtaining a granular solid 11.
As a result of the measurement by the above method, it was confirmed that the solid matter 11 contained water, AE-3000, and C3olf.

[Example 12]
When initially charging the polymerization tank, 9.0 g of a specific compound, CH ₂ ═CH(CF ₂ ) ₅ CF ₃ (hereinafter also referred to as "C6olf"), was added instead of 4.7 g of C3olf, 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 pressed into the polymerization tank after heating and pressurization by adding a TFE/E mixed gas was changed to 7 mL. Furthermore, during polymerization, 0.5 mL of C6olf (an amount equivalent 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 for 90 minutes under normal pressure conditions 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, thereby obtaining 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.

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

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

For the solids produced in each example, the MFR, composition, and melting point of the copolymer contained in the solids, as well as the content, percentage P, and specific surface area of each component of the solids were measured using the methods described above. The measurement results are shown in Table 1 below.

Table 1 shows the composition and physical properties of the copolymers obtained in each example, as well as the measurement and evaluation results of the solid matter.
In the table, the columns "TFE units", "E units" and "A units" indicate the content (unit: mol %) of each unit relative to the total units contained in the solid material of each example.

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, it is possible to manufacture molded bodies with excellent surface properties (Examples 1 to 12).

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

Claims (12)

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 is included,
A solid, characterized in that 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.
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; m represents an integer of 1 to 6.
In formula (2), n represents an integer of 1 to 6. The solid material according to claim 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. The solid material according to claim 1 or 2, wherein the content of the ethylene-based units is 35.00 to 51.90 mol % of the total units contained in the copolymer. The solid material according to claim 1 or 2, wherein the content of the units based on the specific compound in the copolymer is 0.10 to 5.00 mol % relative to the total units contained in the copolymer. The solid material according to claim 1 or 2, wherein the solvent comprises a fluorine-containing solvent. The solid material according to claim 5, wherein the fluorine-containing solvent comprises at least one selected from the group consisting of chlorofluorocarbons, perfluorocarbons, hydrofluorocarbons, and hydrofluoroethers. The solid material according to claim 1 or 2, wherein the solvent comprises water. The solid material according to claim 1 or 2, wherein the content of the solvent is 0.01 to 2 mass% based on the total mass of the solid material. 3. The solid material according to claim 1, having a specific surface area of 0.3 m ² /g or more. A composition comprising the solid material according to claim 1 or 2 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 assistant, and an organic peroxide. A molded body obtained by molding the solid material described in claim 1 or 2. A molded article obtained by molding the composition according to claim 10.