Copolymer

Abstract

Provided is a novel copolymer which contains a constituent unit that is derived from 1,2-difluoroethylene.　The copolymer contains a constituent unit (A) that is derived from 1,2-difluoroethylene. The number of F atoms and the number of H atoms in the copolymer satisfy the relationship of formula (x).　Formula (x): 0.04 ≤ (number of F atoms) / ((number of F atoms) + (number of H atoms)) < 0.50

Description

copolymer

[0001] This disclosure relates to copolymers.

[0002] Fluorine-containing polymers are polymers in which some or all of the hydrogen atoms in the polymer are replaced with fluorine atoms, and they are used in many fields. Fluorine-containing polymers using 1,2-difluoroethylene as the monomer are known (for example, Japanese Patent Publication No. 09-280252 (Patent Document 1), and Journal of Polymer Science: Part A, 1965, Vol. 3, pp. 2975-2982 (Non-Patent Document 1)).

[0003] Japanese Patent Application Publication No. 09-280252

[0004] Journal of Polymer Science: Part A, 1965, Vol.3, p.2975-2982

[0005] This disclosure aims to provide a novel copolymer containing structural units derived from 1,2-difluoroethylene.

[0006] [1] A copolymer comprising a constituent unit (A) derived from 1,2-difluoroethylene, wherein the number of F atoms and the number of H atoms in the copolymer satisfy the following relationship (x): 0.04 ≤ number of F atoms / (number of F atoms + number of H atoms) < 0.50 (x) [2] The copolymer according to [1], wherein in formula (x), the ratio of the number of atoms represented by the number of F atoms / (number of F atoms + number of H atoms) is 0.10 or more. [3] The copolymer according to [1] or [2], wherein, in thermogravimetric differential thermal analysis of the copolymer, the melting point of the copolymer is 50°C or more lower than the 0.1% decomposition temperature of the copolymer. [4] The copolymer according to any one of [1] to [3], wherein the copolymer has a melting point of 120°C or more as determined by thermogravimetric differential thermal analysis. [5] The copolymer according to any one of [1] to [4], further comprising a constituent unit (B) derived from a monomer represented by the following structural formula (B). [In the above structural formula (B), R1 represents a hydrogen atom, a hydroxyl group, a carboxyl group, a methoxycarbonyl group, a tert-butoxy group, or an acetyloxy group, and R2 to R4 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.] [6] The copolymer according to [5], wherein the monomer represented by the above structural formula (B) is ethylene. [7] The above constituent unit (A) and the constituent unit (B) derived from the ethylene. Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ )) is a copolymer as described in [6], wherein the ratio is 10 / 90 to 90 / 10. [8] A constituent unit (A) derived from 1,2-difluoroethylene and a constituent unit (B) derived from ethylene. Ｅ ) including the constituent unit (A) and constituent unit (B Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ )) is a copolymer with a ratio of 10 / 90 to 90 / 10.

[0007] According to this disclosure, a novel copolymer containing constituent units derived from 1,2-difluoroethylene can be provided.

[0008] The following describes this disclosure. In this specification, numerical ranges such as "m to n" include upper and lower limits unless otherwise specified, and represent numerical ranges of "m or greater and n or less".

[0009] (Copolymer (1)) The copolymer of this disclosure (hereinafter also referred to as "Copolymer (1)") contains a constituent unit (A) derived from 1,2-difluoroethylene, and the number of F atoms and H atoms satisfy the following relationship (x): 0.04 ≤ number of F atoms / (number of F atoms + number of H atoms) < 0.50 (x)

[0010] Constituent unit (A) refers to a constituent unit having the same structure as the structure formed by polymerizing 1,2-difluoroethylene. Specifically, it is a constituent unit represented as -CHFCHF-. Constituent unit (A) does not necessarily have to be a constituent unit formed by the actual polymerization of 1,2-difluoroethylene. If it has the same structure as the structure formed by the polymerization of 1,2-difluoroethylene, it is included in constituent unit (A) even if it is formed by a method other than polymerizing 1,2-difluoroethylene.

[0011] 1,2-difluoroethylene exists in both trans (E) and cis (Z) isomers. The constituent unit (A) may be a constituent unit (A-E) having the same structure as the structure formed by polymerizing the trans isomer, or a constituent unit (A-Z) having the same structure as the structure formed by polymerizing the cis isomer. The constituent unit (A) contained in copolymer (1) may consist only of constituent unit (A-E), only of constituent unit (A-Z), or may contain both constituent unit (A-E) and constituent unit (A-Z).

[0012] Copolymer (1) is a novel copolymer that contains constituent unit (A) and satisfies the relationship of formula (x). By satisfying the relationship of formula (x), copolymer (1) can have a larger temperature difference (Tm-Td1) between its melting point (Tm) and its 0.1% decomposition temperature (Td1) than fluorine-containing polymers with a low proportion of F atoms, such as polyvinyl fluoride (PVF). Fluorine-containing polymers with a low proportion of F atoms tend to decompose at temperatures near their melting point, and are therefore sometimes molded by extrusion molding after swelling the resin with a solvent, rather than by melt molding. As described later, the above temperature difference (Tm-Td1) of copolymer (1) is preferably 50°C or higher, so copolymer (1) can be suitably used in melt molding such as injection molding, extrusion molding, and blow molding.

[0013] In the above formula (x), the ratio of the number of atoms expressed as F atoms / (F atoms + H atoms) may be 0.10 or more and less than 0.50, 0.12 or more and 0.48, 0.15 to 0.45, 0.16 to 0.43, 0.20 to 0.42, 0.25 to 0.40, or 0.30 to 0.38.

[0014] In this specification, the ratio of the number of atoms in copolymer (1) refers to the value calculated after compositional analysis by NMR (Nuclear Magnetic Resonance). However, the ratio of the number of atoms in copolymer (1) can also be measured by elemental analysis using ESCA (Electron Spectroscopy for Chemical Analysis), XPS (X-ray Photoelectron Spectroscopy), or ICP (Inductively Coupled Plasma) analysis. In the ICP method, the F concentration of copolymer (1) can be determined by the following procedure. First, about 0.1 to 1.0 g of copolymer (1) is ashed in a muffle furnace and then dissolved in acid. The polymer dissolved in acid is atomized using a nebulizer and introduced into an argon plasma for ionization. The ionized polymer is introduced into a mass spectrometer, separated and detected based on the mass-to-charge ratio (m / z), and the concentration of element F in copolymer (1) is calculated based on the obtained spectral data.

[0015] The copolymer (1) is preferably a crystalline polymer. The degree of crystallinity of copolymer (1) may be greater than 0.5% and less than or equal to 80%, may be between 1% and 75%, may be between 10% and 70%, may be between 20% and 65%, or may be between 30% and 60%. The degree of crystallinity of copolymer (1) is calculated by the ratio of the amorphous peak to the crystalline peak obtained by X-ray crystal diffraction, as will be explained in the examples described later.

[0016] The copolymer (1) preferably has a melting point (Tm). The melting point (Tm) of the copolymer (1) is preferably 120°C or higher, but may also be 125°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, 160°C or higher, 170°C or higher, 120 to 250°C, 125 to 240°C, 130 to 230°C, 140 to 220°C, 150 to 210°C, 160 to 200°C, or 170 to 190°C.

[0017] The melting point (Tm) of copolymer (1) is preferably 50°C or more lower than the 0.1% decomposition temperature (Td1) of copolymer (1). The temperature difference (Tm-Td1) between the melting point (Tm) of copolymer (1) and the 0.1% decomposition temperature (Td1) is preferably 50°C or more, but may be 60°C or more, 70°C or more, 80°C or more, 50-150°C, 60-140°C, 70-130°C, or 80-120°C.

[0018] The temperature difference (Tm-Td2) between the melting point (Tm) and the 1% decomposition temperature (Td2) of copolymer (1) may be 110°C or higher, 120°C or higher, 130°C or higher, 140°C or higher, 150°C or higher, 110-210°C, 120-200°C, 130-190°C, 140-180°C, or 150-170°C.

[0019] The melting point (Tm), 0.1% decomposition temperature (Td1), and 1% decomposition temperature (Td2) of copolymer (1) are values ​​measured by differential scanning calorimetry (TG / DTA measurement). As will be explained in the examples described later, the melting point (Tm) is the temperature corresponding to the maximum value of the DSC curve obtained by heating copolymer (1) at 10°C / min using a differential scanning calorimetry. The 0.1% decomposition temperature (Td1) and 1% decomposition temperature (Td2) are the temperatures at which a weight loss of 0.1% and 1%, respectively, is observed when copolymer (1) is heated at 10°C / min using a differential scanning calorimetry.

[0020] Structural units other than the structural unit (A) contained in the copolymer (1) are not particularly limited as long as they can satisfy the relationship of formula (x). It is preferable that the copolymer (1) further contains a structural unit (B) derived from a monomer represented by the following structural formula (B) (hereinafter also referred to as "monomer (B)") in addition to the structural unit (A). [In structural formula (B), R¹ represents a hydrogen atom (-H), a hydroxy group (-OH), a carboxy group (-COOH), a methoxycarbonyl group (-COOCH ３ ), a tert-butoxy group (-OC(CH ３ ) ３ ) or an acetyloxy group (-OCOCH ３ ); and R² to R⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.]]

[0021] The structural unit (B) refers to a structural unit having the same structure as the structure formed by polymerizing the monomer (B). Specifically, it is a structural unit represented by -C(R¹R³)C(R²R⁴)-. The structural unit (B) does not need to be a structural unit actually formed by polymerization of the monomer (B). Any structural unit having the same structure as the structure formed by polymerizing the monomer (B) is included in the structural unit (B), even if the structural unit is formed by a method other than polymerizing the monomer (B).

[0022] Since the copolymer (1) tends to have crystallinity when it contains the structural unit (B), the copolymer (1) having a large temperature difference (Tm-Td1) and / or a large temperature difference (Tm-Td2) described above is easily obtained.

[0023] Examples of the C1-C3 hydrocarbon group represented by R² to R⁴ include a methyl group (-CH ３ ), an ethyl group (-CH ２ CH ３ ), a 1-propyl group (-(CH ２ ) ２ CH ３ ), and a 2-propyl group (-CH(CH ３ ) ２ ).

[0024] Monomer (B) is a monomer that can be polymerized by heat, light, or the use of a radical polymerization initiator. Examples of R1 to R4 in structural formula (B) include the combinations described below.

[0025] In structural formula (B), when R1 is a hydrogen atom, R2 to R4 are each preferably independently a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and more preferably a hydrogen atom. Examples of such monomers (B) include alkenes such as ethylene, propylene, 1-butene, 2-butene, 2-methylpropene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene, 4-octene, and 3-methyl-1-butene.

[0026] In structural formula (B), if R1 is a hydroxyl group, it is preferable that R2 to R4 are hydrogen atoms. Examples of such monomers (B) include vinyl alcohol.

[0027] In structural formula (B), if R1 is a carboxyl group, it is preferable that R2 and R4 are hydrogen atoms and R3 is a hydrogen atom or a methyl group. An example of such monomer (B) is (meth)acrylic acid. (Meth)acrylic acid means acrylic acid or methacrylic acid.

[0028] In structural formula (B), when R1 is a methoxycarbonyl group, it is preferable that R2 and R4 are hydrogen atoms and R3 is a hydrogen atom or a methyl group. An example of such monomer (B) is methyl (meth)acrylate.

[0029] In structural formula (B), when R1 is a tert-butoxy group, it is preferable that R2 and R4 are hydrogen atoms and R3 is a hydrogen atom. An example of such monomer (B) is tert-butyl vinyl ether.

[0030] In structural formula (B), if R1 is an acetyloxy group, it is preferable that R2 to R4 are hydrogen atoms. Examples of such monomers (B) include vinyl acetate.

[0031] The monomer (B) is preferably ethylene. When the monomer (B) is ethylene, the constituent unit (B) is a constituent unit (B) derived from ethylene. Ｅ ) is the constituent unit (B Ｅ ) is -CH ２ CH ２ It is a constituent unit represented by -. Constituent unit (B Ｅ The copolymer (1) containing ) tends to be crystalline, and therefore the above-mentioned temperature difference (Tm-Td1) and / or temperature difference (Tm-Td2) tend to be large.

[0032] Copolymer (1) is a constituent unit (B Ｅ ) if it includes constituent unit (A) and constituent unit (B) in copolymer (1) Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ The molar ratio (constituent unit (A) / constituent unit (B)) is preferably 10 / 90 to 90 / 10. Ｅ )) may be 20 / 80 to 85 / 15, 25 / 75 to 80 / 20, 30 / 70 to 75 / 25, 33 / 67 to 70 / 30, or 40 / 60 to 67 / 33. As long as the above molar ratio is within the above range, the constituent units (B Ｅ The copolymer (1) containing ) tends to be crystalline, and the above-mentioned temperature difference (Tm-Td1) and / or temperature difference (Tm-Td2) tend to be large.

[0033] Copolymer (1) may contain one or more types of constituent units other than constituent units (A) and constituent unit (B). The total ratio of constituent units (A) and constituent unit (B) to the total number of constituent units of copolymer (1) may be 80 to 100 mol%, 85 to 99 mol%, or 90 to 98 mol%. If copolymer (1) contains two or more types of constituent unit (B), the content of constituent unit (B) is the total amount of the two or more types of constituent unit (B). The presence of each of the above-mentioned constituent units in copolymer (1) can be determined by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of constituent unit.

[0034] The weight-average molecular weight of copolymer (1) is preferably 5,000 to 5,000,000, but may also be 8,000 to 3,000,000, or 10,000 to 2,000,000. The weight-average molecular weight can be measured based on the results obtained by gel permeation chromatography (GPC), using standard polystyrene as the reference. For example, it can be measured under the following conditions. However, any solvent in which the polymer dissolves can be used as the developing solvent, and any column suitable for the solvent can be used. GPC apparatus: TOSOH AS-8010, CO-8020, and SIMADZURID-10A Column: GMHHR-H 3 columns Developing solvent: Dimethylformamide [DMF] Sample concentration: 0.05% by mass

[0035] (Copolymer (2)) The copolymer of the present disclosure (hereinafter also referred to as "Copolymer (2)") comprises a constituent unit (A) derived from 1,2-difluoroethylene and a constituent unit (B) derived from ethylene. Ｅ ) includes constituent unit (A) and constituent unit (B Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ The ratio is 10 / 90 to 90 / 10.

[0036] Component unit (A) and component unit (B) Ｅ The molar ratio in copolymer (2) is as described in copolymer (1). Ｅ )) can be within the range of the molar ratio described in copolymer (1).

[0037] Copolymer (2) is preferably a crystalline polymer. Copolymer (2) can have a large temperature difference between its melting point (Tm) and its 0.1% decomposition temperature (Td1) and / or 1% decomposition temperature (Td2). Therefore, copolymer (2) can be suitably used in melt molding such as injection molding, extrusion molding, and blow molding. The degree of crystallinity, melting point (Tm), temperature difference (Tm-Td1), and temperature difference (Tm-Td2) in copolymer (2) can be within the range described for copolymer (1).

[0038] Copolymer (2) may satisfy the relationship of formula (x) described in copolymer (1). In formula (x), the ratio of the number of atoms expressed as number of F atoms / (number of F atoms + number of H atoms) is within the range described in copolymer (1).

[0039] Copolymer (2) consists of constituent unit (A) and constituent unit (B Ｅ In addition to these constituent units, it may also contain one or more other constituent units. Constituent units (A) and constituent units (B) for all constituent units of copolymer (2) Ｅ The total proportion of ) may be 70 to 100 mol%, 75 to 99 mol%, 80 to 98 mol%, 85 to 95 mol%, or 88 to 92 mol%. The constituent units contained in copolymer (2) can be identified by the method described in copolymer (1).

[0040] The weight-average molecular weight of copolymer (2) can be within the range described for copolymer (1).

[0041] (Method for producing copolymers (1) and (2)) Copolymer (1) can be produced by copolymerizing 1,2-difluoroethylene with another monomer other than 1,2-difluoroethylene. The other monomer is, for example, monomer (B). Copolymer (2) can be produced by copolymerizing 1,2-difluoroethylene with ethylene.

[0042] The 1,2-difluoroethylene used in the production of copolymer (1) and copolymer (2) (hereinafter collectively referred to as "the copolymer") can be synthesized, for example, by the method described in International Publication No. 2019 / 216239.

[0043] The purity of the 1,2-difluoroethylene used in the production of this copolymer is preferably 99.5% by mass or higher, more preferably 99.8% by mass or higher, and even more preferably 99.9% by mass or higher. The purity of the 1,2-difluoroethylene can be adjusted to the above level after synthesis by separation by preparative chromatography or by multi-stage rectification.

[0044] This copolymer can be obtained by copolymerizing 1,2-difluoroethylene with another monomer in the presence of a polymerization initiator. Common polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, or suspension polymerization can be employed for copolymerization. From the viewpoint of ease of industrial production, copolymerization is preferably carried out by solution polymerization, emulsion polymerization, or suspension polymerization.

[0045] The polymerization initiator can be either an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator, but it is preferable to use an oil-soluble radical polymerization initiator.

[0046] Examples of oil-soluble radical polymerization initiators include known oil-soluble peroxides. These include dialkyl peroxycarbonates such as dinormal propyl peroxydicarbonate, diisopropyl peroxydicarbonate, disec-butyl peroxydicarbonate, and di-2-ethoxyethyl peroxydicarbonate; peroxyesters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate; dialkyl peroxides such as di-t-butyl peroxide; and di[fluoro(or fluorochloro)acyl]peroxides.

[0047] Di[fluoro(or fluorochloro)acyl]peroxides include, for example, [(RfCOO)-] ２ This is a compound represented by (Rf represents a perfluoroalkyl group, an ω-hydroperfluoroalkyl group, or a fluorochloroalkyl group).

[0048] Examples of di[fluoro(or fluorochloro)acyl]peroxides include di(ω-hydro-dodecafluorohexanoyl)peroxide, di(ω-hydro-tetradecafluoroheptanoyl)peroxide, di(ω-hydro-hexadecafluorononanoyl)peroxide, di(perfluoropropionyl)peroxide, di(perfluorobutyryl)peroxide, di(perfluoropareryl)peroxide, di(perfluorohexanoyl)peroxide, di(perfluoroheptanoyl)peroxide, di(perfluorooctanoyl)peroxide, di(perfluorononanoyl)peroxide, di(ω-chloro-hexafluorobutyryl)peroxide, and di(ω-chloro-decafluorohexanoyl) Examples include (I) peroxide, di(ω-chloro-tetradecafluorooctanoyl) peroxide, ω-hydro-dodecafluoroheptanoyl-ω-hydrohexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydrododecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl) peroxide, di(trichlorooctafluorohexanoyl) peroxide, di(tetrachloroundafluorooctanoyl) peroxide, di(pentachlorotetradecafluorodecanoyl) peroxide, and di(undachlorotriacontafluorodocosanoyl) peroxide.

[0049] Examples of water-soluble radical polymerization initiators include known water-soluble peroxides. These include salts such as persulfates, perborates, perchlorates, superphosphates, and percarbonates (examples of salt types include ammonium salts, potassium salts, and sodium salts); organic peroxides such as disuccinate peroxide and diglutarate peroxide; t-butyl permalate; t-butyl hydroperoxide; and others. Peroxides may be used in combination with reducing agents such as sulfites and sulfites. The amount (by mass) of the reducing agent used may be 0.1 to 20 times the mass of the peroxide.

[0050] The amount of radical polymerization initiator added is not particularly limited, but an amount sufficient to prevent a significant decrease in the polymerization rate (for example, a few ppm relative to water concentration) should be added all at once, sequentially, or continuously at the beginning of copolymerization. The upper limit of the amount of radical polymerization initiator added should be set in the polymerization apparatus so that the heat of the polymerization reaction can be removed.

[0051] In copolymerization of 1,2-difluoroethylene with other monomers, surfactants, hydrophilic compounds, chain transfer agents, and solvents may be used.

[0052] Any known surfactant can be used. Examples of surfactants include nonionic surfactants, anionic surfactants, and cationic surfactants. The amount of surfactant added (relative to the polymerization water) is preferably 10 ppm to 20% by mass, more preferably 10 to 5000 ppm, and even more preferably 50 to 5000 ppm. A reactive emulsifier may be used as the surfactant. The reactive emulsifier is not particularly limited as long as it is a compound having one or more unsaturated bonds and one or more hydrophilic groups.

[0053] Examples of hydrophilic compounds include known unsaturated hydrophilic compounds and hydrophilic polymers obtained by polymerizing known unsaturated hydrophilic compounds. The amount of hydrophilic compound added (relative to polymerization water) is preferably 10 to 5000 ppm, and more preferably 50 to 5000 ppm.

[0054] Examples of chain transfer agents include hydrocarbons such as ethane, isopentane, n-hexane, and cyclohexane; aromatics such as toluene and xylene; ketones such as acetone; esters such as ethyl acetate, butyl acetate, dimethyl malonate, diethyl malonate, and dimethyl succinate; alcohols such as methanol, ethanol, and isopropanol; and mercaptans such as methyl mercaptan. Carbon tetrachloride, chloroform, methylene chloride, methyl chloride, monoiodomethane, 1-iodoethane, 1-iodo-n-propane, 1-iodoperfluoropropane, 2-iodoperfluoropropane, 1-iodoperfluorobutane, 1-iodoperfluoropentane, 1-iodoperfluorohexane, 1,3-diiodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF ２ Br ２ , BrCF ２ CF ２ Br, CF ３ CFBrCF ２ Br, CFClBr ２ , BrCF ２ CFClBr, CFBrClCFClBr, BrCF ２ CF ２ CF ２ Br, BrCF ２ CFBrOCF ３Examples include 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, and halogenated hydrocarbons such as monoiodomonobromo substituted, diiodomonobromo substituted, (2-iodoethyl) or (2-bromoethyl) substituted derivatives of benzene; and others. These compounds can be used individually or in combination of two or more. The amount of chain transfer agent added may vary depending on the magnitude of the chain transfer constant of the chain transfer agent used, but it can usually be used in the range of 0.01 to 20% by mass relative to the polymerization solvent.

[0055] Examples of solvents include water and mixed solvents of water and alcohol.

[0056] In solution polymerization, a fluorinated solvent may be used. In suspension polymerization, a fluorinated solvent may be used in addition to water. Examples of fluorinated solvents include CH4. ３ CClF ２ ,CH ３ CCl ２ F, CF ３ CF ２ CCl ２ H, and CF ２ ClCF ２ Hydrochlorofluoroalkanes such as CFHCl; CF ２ ClCFClCF ２ CF ３ , and CF ３ CFClCFClCF ３ Chlorofluoroalkanes such as CF ３ CFHCFHCF ２ CF ２ CF ３ CF ２ HCF ２ CF ２ CF ２ CF ２ H, and CF ３ CF ２ CF ２ CF ２ CF ２ CF ２ CF ２Hydrofluoroalkanes such as H; CH ３ OC ２ F ５ , CH ３ OC ３ F ７ CF ３ CF ２ CH ２ OCHF ２ , CF ３ CHFCF ２ OCH ３ , CHF ２ CF ２ OCH ２ F, (CF ３ ) ２ CHCF ２ OCH ３ , CF ３ CF ２ CH ２ OCH ２ CHF ２ , and hydrofluoroethers such as CF ３ CHFCF ２ OCH ２ CF ３ ; perfluorocyclobutane, CF ３ CF ２ CF ２ CF ３ , CF ３ CF ２ CF ２ CF ２ CF ３ , and perfluoroalkanes such as CF ３ CF ２ CF ２ CF ２ CF ２ CF ３ ; and the like. The fluorine-based solvent is preferably a perfluoroalkane or a hydrofluoroether. The amount of the fluorine-based solvent used is preferably 10 to 100% by mass relative to the aqueous medium from the viewpoints of suspensibility and economic efficiency.

[0057] The polymerization temperature, polymerization pressure, and polymerization time in copolymerization vary depending on the type and amount of solvent used, the vapor pressure, and the type of polymerization initiator, but can be, for example, -15 to 150°C, 0 to 9.8 MPa, and 1 to 24 hours, respectively. When an oil-soluble radical polymerization initiator containing fluorine atoms is used as the polymerization initiator in solution polymerization, the polymerization temperature is preferably -15 to 70°C, and more preferably 10 to 65°C. When an oil-soluble radical polymerization initiator containing fluorine atoms is used in emulsion polymerization and suspension polymerization, the polymerization temperature is preferably 10 to 95°C. When a water-soluble radical polymerization initiator is used as the polymerization initiator, the polymerization temperature is preferably 10 to 95°C.

[0058] (Forms of Use of Copolymers (1) and (2)) The copolymer may be dissolved in a general-purpose solvent as needed to form a resin solution. Examples of general-purpose solvents include: ketone solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), acetone, diethyl ketone, dipropyl ketone, and cyclohexanone; ester solvents such as ethyl acetate, methyl acetate, propyl acetate, butyl acetate, and ethyl lactate; ether solvents such as tetrahydrofuran, methyltetrahydrofuran, and dioxane; amide solvents such as N,N-dimethylformamide (DMF) and dimethylacetamide; and so on. The general-purpose solvent can be used as one solvent selected from the above or as a mixed solvent of two or more. It is desirable that the content of amide solvents in the general-purpose solvent used in the resin solution be 50% by mass or less.

[0059] The concentration of the copolymer in the resin solution is not particularly limited, but can be, for example, 1.0 to 10.0% by mass, 2.0 to 9.0% by mass, or 2.5 to 8.0% by mass.

[0060] This copolymer may be combined with other polymers or compounds as needed to form a composition. The composition may contain other components besides this copolymer to exhibit various properties. Other components may include: pigments and dyes such as carbon black, titanium dioxide, copper phthalocyanine blue, perylene red, iron oxide, and lead yellow; lubrication agents such as polytetrafluoroethylene lubricant and silicone oil; conductivity-imparting substances such as carbon black, carbon nanotubes, graphite, tin oxide, and ionic liquids; fiber reinforcing agents such as carbon fiber, glass fiber, aramid fiber, potassium titanate whiskers, aluminum borate whiskers, and calcium carbonate whiskers; thermal conductivity-imparting agents such as alumina, magnesium oxide, and graphite; and fillers such as talc, coke, mica, and glass beads. Polymeric materials such as fluororubber, ethylene-propylene-diene rubber (EPDM), polyphenylene sulfide, polyetheretherketone, polyetherimide, polyamideimide, polysulfone, polyethersulfone, liquid crystal polymer, polyamide, semi-aromatic polyamide, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and chlorotrifluoroethylene-ethylene copolymer (ECTFE); modifiers such as aminosilane and phenylsilane; nucleating agents; foaming agents; crosslinking agents such as triallyl isocyanurate; antioxidants; light stabilizers; and ultraviolet absorbers. The content of other components can be appropriately selected depending on the properties to be imparted.

[0061] For example, the antioxidants mentioned above include copper oxide, silver oxide, magnesium oxide, alumina, titanium oxide, and zinc oxide, with copper oxide and alumina being preferred.

[0062] The antioxidant content in the composition is preferably 0.001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, even more preferably 0.005 to 10 parts by mass, and particularly preferably 0.05 to 5 parts by mass, per 100 parts by mass of the copolymer.

[0063] (Uses of Copolymers (1) and (2)) This copolymer can be used in various molded articles such as films, sheets, tubes, hoses, sealing materials, melt-spun fibers, wires, nonwoven fabrics, and wire coating materials. This copolymer may also be used as a coating material. When using this copolymer in a molded article, the molded article may be obtained using a composition containing this copolymer.

[0064] The method for obtaining a molded article using this copolymer is not particularly limited, and known molding methods can be used. For example, a molded article of this copolymer may be obtained by mold molding, extrusion molding, injection molding, ram extrusion, press molding, vacuum molding, transfer molding, blow molding, nanoimprinting, and melt spinning. A molded article of this copolymer can be used, for example, in containers, optical materials, building materials, semiconductor-related materials, display-related materials, automotive materials, shipbuilding materials, aircraft materials, power generation-related materials, laminates, and lifestyle and leisure goods.

[0065] Examples of containers include tanks, bottles, chemical solution bags, and Tedlar bags for gas sampling.

[0066] Examples of optical materials include optical components, eyeglass lenses, optical lenses, optical cells, DVD discs, photodiodes, anti-reflective materials, and microlens arrays.

[0067] Examples of building materials include shop windows, display cases, membrane materials for membrane structures (sports facilities, horticultural facilities, and atriums, etc.), roofing materials, ceiling materials, exterior wall materials, interior wall materials, and covering materials. In addition to membrane materials for membrane structures, examples of outdoor-use panel materials include soundproof walls, windbreak fences, wave overtopping fences, garage canopies, shopping malls, walkway walls, glass shatterproof films, heat-resistant and water-resistant sheets, tent materials for tent warehouses, sunshade membrane materials, partial roofing materials for letting in light, window materials that replace glass, opening materials such as glass substitutes, flame partition membrane materials, curtains, exterior wall reinforcement, waterproof membranes, smoke barriers, non-combustible transparent partitions, road reinforcement, interior (lighting, walls, brands, etc.), exterior (tents, signs, etc.), large-scale greenhouses, and membrane materials (roofing materials, ceiling materials, exterior wall materials, interior wall materials, etc.).

[0068] Examples of electronic materials include printed circuit boards, ceramic circuit boards and other wiring boards, electronic materials (printed circuit boards, wiring boards, insulating films, and release films, etc.), film capacitors, electronic and electrical components, home appliance casings, and precision machine parts.

[0069] Examples of semiconductor-related materials include protective films for semiconductor devices (interlayer insulating films, buffer coat films, passivation films, alpha-ray shielding films, device encapsulants, interlayer insulating films for high-density mounting substrates, moisture-proof films for high-frequency devices (moisture-proof films for RF circuit elements, GaAs elements, and InP elements, etc.), pellicle films, photolithography, and biochips.

[0070] Display-related materials include surface protective films for displays, touch panels, various types of displays (PDP, LCD, FED, organic EL, and projection TV), surfaces for electrowetting, and image-forming articles.

[0071] Examples of automotive materials include convertible tops, vibration damping materials, and car bodies.

[0072] Examples of power generation-related materials include solar cells, intermediates for electrolyte materials in polymer electrolyte fuel cells, electrostatic induction converters (vibration generators, actuators, and sensors, etc.), power generation devices, electrets used in electrostatic induction converters such as microphones, surface materials for solar cell modules, mirror protective materials for solar thermal power generation, surface materials for solar water heaters, and photovoltaic technology.

[0073] Examples of laminates include films laminated with thermoplastic resins such as polyimide.

[0074] Examples of everyday leisure goods include fishing rods, rackets, golf clubs, and projection screens.

[0075] Coating materials using this copolymer include water-repellent coatings, release agents, low-reflection coatings, antifouling coatings, non-stick coatings, waterproof and moisture-proof coatings, insulating films, chemical-resistant coatings, etching protective films, low refractive index films, ink-repellent coatings, gas barrier films, patterned functional films, surface protective films for display color filters, antifouling and anti-reflective films for solar cell cover glass, moisture-proof and anti-reflective coatings for deliquescent crystals and phosphate-based glass, phase-shift masks, surface protective and antifouling coatings for photomasks, liquid-repellent coatings for photoresists for immersion lithography, release coatings for contact lithomasks, and nanoimprint coatings. Examples include mold release coatings, passivation films for semiconductor elements and integrated circuits, gas barrier films for silver electrodes of circuit boards and light-emitting elements such as LEDs, liquid crystal alignment films for liquid crystal display elements, lubricating coatings for magnetic recording media, gate insulating films, devices using the electrowetting principle, electret films, chemical-resistant coatings for MEMS processes, antifouling coatings for medical devices, chemical-resistant, antifouling, bio-resistant, or liquid-repellent coatings for devices utilizing microfluidics technology, low refractive index materials for multilayer coatings of optical filters, hydrophilic and hydrophobic patterning, and patterned optical elements.

[0076] The present disclosure will be further described below with reference to examples and comparative examples. Unless otherwise specified, "%" and "parts" in the examples and comparative examples refer to mass percent and parts by mass, respectively.

[0077] [Preparation of 1,2-difluoroethylene] 1,2-difluoroethylene synthesized according to the example described in International Publication No. 2019 / 216239 was separated by preparative gas chromatography to prepare 1,2-difluoroethylene as the E-isomer (trans isomer) with a purity of 99.9% by mass or higher. The purity of 1,2-difluoroethylene was determined to be 99.9% by mass or higher by confirming that no impurity peaks appeared in gas chromatography-mass spectrometry (GC / MC) of the 1,2-difluoroethylene.

[0078] [Compositional Analysis (Ratio of Atom Numbers)] The number of F atoms and H atoms in the polymer were calculated after compositional analysis of the polymer by ¹H-NMR, ¹³C-NMR, and / or ¹⁹F-NMR. From the ratio of each constituent unit obtained from the compositional analysis, the number of F atoms / (number of F atoms + number of H atoms) was calculated. NMR measurements were performed by solution NMR, molten NMR, or solid NMR.

[0079] [Composition Analysis (Molar Ratio of Constituent Units)] The molar ratio of each constituent unit of the copolymer of 1,2-difluoroethylene and ethylene can be determined from the spectrum obtained by 1H-NMR measurement using the following formula: Constituent Unit (A) / Constituent Unit (B) Ｅ ) = (2 × S) / S Ｅ [In the formula, S represents the integral value of the 1H-NMR signal derived from 1,2-difluoroethylene at concentrations of 4.0 to 6.0 ppm, and S Ｅ This represents the integral value of the ¹H-NMR signal derived from ethylene at concentrations of 0.7–2.2 ppm.

[0080] [Example 1] A 0.5 L stainless steel autoclave was thoroughly purged with vacuum nitrogen. Then, the autoclave was degassed under vacuum, and 200 g of HFE-347pc-f (1,1,2,2-tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane) was introduced into the vacuumed autoclave. After raising the temperature of the autoclave to 28°C, 1,2-difluoroethylene was charged to a pressure of 0.582 MPaG, and then ethylene was introduced to a pressure of 0.8 MPaG. Next, 4.0 g of an 8% di(ω-hydrododecafluoroheptanoyl)peroxide (hereinafter also referred to as "DHP") perfluorohexane solution was added to the autoclave to start polymerization. The starting pressure was 0.8 MPaG. To maintain polymerization pressure, a mixed gas of 1,2-difluoroethylene / ethylene = 70 / 30 [mol%] was flowed through the autoclave, and the temperature inside the autoclave was maintained at 28°C for 2.5 hours. After that, the pressure was released to return to atmospheric pressure, the reaction product was washed with water, and dried to obtain 10 g of polymer powder. The obtained polymer consists of constituent units (A) derived from 1,2-difluoroethylene and constituent units (B) derived from ethylene. ＥIt is a copolymer of (A) and (B), with an atomic ratio (number of F atoms / (number of F atoms + number of H atoms)) of 0.35, and the constituent units (A) and (B) are Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ The ratio was 69.9 / 30.1.

[0081] [Example 2] A 0.5 L stainless steel autoclave was thoroughly purged with vacuum nitrogen. Then, the autoclave was degassed under vacuum, and 200 g of HFE-347pc-f was introduced into the vacuumed autoclave. After raising the temperature of the autoclave to 28°C, ethylene was added to bring the pressure to 0.472 MPaG, and then 1,2-difluoroethylene was introduced to bring the pressure to 0.8 MPaG. Next, 8.0 g of DHP perfluorohexane solution was added to the autoclave to start polymerization. The starting pressure was 0.8 MPaG. To maintain the polymerization pressure, a mixed gas of 1,2-difluoroethylene / ethylene = 55 / 45 [mol%] was flowed through the autoclave, and the temperature inside the autoclave was maintained at 28°C for 4 hours. After that, the pressure was released to return to atmospheric pressure, the reaction product was washed with water, and dried to obtain 10 g of polymer powder. The resulting polymer consists of a constituent unit (A) derived from 1,2-difluoroethylene and a constituent unit (B) derived from ethylene. Ｅ It is a copolymer of ), with an atomic ratio (number of F atoms / (number of F atoms + number of H atoms)) of 0.28, and the constituent units (A) and (B) Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ The ratio was 55.1 / 44.9.

[0082] [Example 3] A 0.5 L stainless steel autoclave was thoroughly purged with vacuum nitrogen. Then, the autoclave was degassed under vacuum, and 200 g of HFE-347pc-f was introduced into the vacuumed autoclave. After raising the temperature of the autoclave to 28°C, ethylene was charged to a pressure of 0.492 MPaG, and then 1,2-difluoroethylene was introduced to a pressure of 0.8 MPaG. Next, 8.0 g of DHP perfluorohexane solution was added to the autoclave to start polymerization. The starting pressure was 0.8 MPaG. To maintain the polymerization pressure, a mixed gas of 1,2-difluoroethylene / ethylene = 50 / 50 [mol%] was flowed through the autoclave, and the temperature inside the autoclave was maintained at 28°C for 5 hours. After that, the pressure was released to return to atmospheric pressure, the reaction product was washed with water, and dried to obtain 9 g of polymer powder. The resulting polymer consists of a constituent unit (A) derived from 1,2-difluoroethylene and a constituent unit (B) derived from ethylene. Ｅ It is a copolymer of (A) and (B), with an atomic ratio (number of F atoms / (number of F atoms + number of H atoms)) of 0.25, and the constituent units (A) and (B) are Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ The ratio was 49.7 / 50.3.

[0083] [Example 4] A 0.5 L stainless steel autoclave was thoroughly purged with vacuum nitrogen. Then, the autoclave was degassed under vacuum, and 200 g of HFE-347pc-f was introduced into the vacuum-sealed autoclave. After raising the temperature of the autoclave to 28°C, ethylene was added to bring the pressure to 0.582 MPaG, and then 1,2-difluoroethylene was introduced to bring the pressure to 0.8 MPaG. Next, 8.0 g of DHP perfluorohexane solution was added to the autoclave to start polymerization. The starting pressure was 0.8 MPaG. To maintain the polymerization pressure, a mixed gas of 1,2-difluoroethylene / ethylene = 30 / 70 [mol%] was flowed through the autoclave, and the temperature inside the autoclave was maintained at 28°C for 7 hours. After that, the pressure was released to return to atmospheric pressure, the reaction product was washed with water, and dried to obtain 7 g of polymer powder. The resulting polymer consists of a constituent unit (A) derived from 1,2-difluoroethylene and a constituent unit (B) derived from ethylene. ＥIt is a copolymer of (A) and (B), with an atomic ratio (number of F atoms / (number of F atoms + number of H atoms)) of 0.17, and the constituent units (A) and (B) are 0.17. Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ The ratio was 33.3 / 66.7.

[0084] [Comparative Example 1] Polyvinyl fluoride (purchased product, Tedlar bag for analysis) was prepared. NMR measurement was performed and found that the above polyvinyl fluoride was a homopolymer of vinyl fluoride, with an atomic ratio (number of F atoms / (number of F atoms + number of H atoms)) of 0.25.

[0085] [Differential Scanning Calorimetry (TG / DTA Measurement)] Using a differential scanning calorimeter RDC220 (Seiko Instruments), thermal measurements of the polymer were performed at a heating rate of 10°C / min, and the temperature corresponding to the maximum value in the obtained DSC curve was defined as the melting point (Tm). Thermal measurements were performed using the same procedure as above, and the temperatures at which a 0.1% and 1% weight loss of the polymer was observed were defined as the 0.1% decomposition temperature (Td1) and the 1% decomposition temperature (Td2), respectively. The results are shown in Table 1.

[0086] [Calculation of Crystallinity] Polymer powder was compressed and molded at 150°C to form a sheet with a thickness of 0.2 mm. The sheet was measured using a fully automated multi-purpose X-ray diffractometer (SmartLab: manufactured by Rigaku Corporation) with a measurement angle of 10 to 30°, a light source of Cu / Kα, and a wavelength of 1.5418 Å. Peak tops with a full width at half maximum of 2 or more between 17.0 and 18.5° were considered amorphous regions, and other peak tops were considered crystalline regions. After waveform separation of each peak, the crystallinity was calculated from the peak area of ​​each peak according to the following formula. The results are shown in Table 1. Crystallinity [%] = Peak area of ​​crystalline region / (Peak area of ​​crystalline region + Peak area of ​​amorphous region) × 100

[0087] [Measurement of Elastic Modulus] Under conditions of a temperature 30°C higher than the melting point and a pressure of 3.0 MPa, the polymer was pressed and molded to produce films with a thickness of 50 to 300 μm. These films were cut into strips 30 mm long and 5 mm wide, and these strips were used as test specimens for measuring the elastic modulus.

[0088] Using a dynamic viscoelastic device (DVA220, manufactured by IT Measurement Control Co., Ltd.), the elastic modulus of the test specimens obtained above was measured under the following conditions: tensile mode, grip width 20 mm, measurement temperature from -50°C to 140°C, heating rate 2°C / min, and frequency 10 Hz. The elastic moduli at 25°C and 120°C are shown in Table 1.

[0089] [Evaluation of moldability] Under the conditions of temperature and 3.0 MPa shown in Table 1, polymers were pressed and molded to produce films with a thickness of 50 to 300 μm. These films were cut into pieces 30 mm long and 5 mm wide, and the resulting film pieces were visually inspected and evaluated according to the following criteria. The results are shown in Table 1. a: A good film with no cracks. b: A film could be made, but there were some cracks. c: The film was cracked so much that it could not be made.

[0090]

Claims

1. A copolymer containing a constituent unit (A) derived from 1,2-difluoroethylene, wherein the number of F atoms and H atoms in the copolymer satisfy the following relationship (x): 0.04 ≤ number of F atoms / (number of F atoms + number of H atoms) < 0.50 (x) 2. The copolymer according to claim 1, wherein in formula (x), the ratio of the number of atoms represented by F atoms / (number of F atoms + number of H atoms) is 0.10 or more.

3. The copolymer according to claim 1 or 2, wherein, in thermogravimetric differential thermal analysis of the copolymer, the melting point of the copolymer is 50°C or more lower than the 0.1% decomposition temperature of the copolymer.

4. The copolymer according to any one of claims 1 to 3, wherein the copolymer has a melting point of 120°C or higher as determined by thermogravimetric differential thermal analysis.

5. The copolymer according to any one of claims 1 to 4, further comprising a constituent unit (B) derived from a monomer represented by the following structural formula (B). [In the above structural formula (B), R1 represents a hydrogen atom, a hydroxyl group, a carboxyl group, a methoxycarbonyl group, a tert-butoxy group, or an acetyloxy group, and R2 to R4 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.] 6. The copolymer according to claim 5, wherein the monomer represented by structural formula (B) is ethylene.

7. The constituent unit (A) and the constituent unit (B) derived from ethylene. Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ The copolymer according to claim 6, wherein the ratio is 10 / 90 to 90 / 10.

8. Constituent units (A) derived from 1,2-difluoroethylene and constituent units (B) derived from ethylene Ｅ ) including the constituent unit (A) and constituent unit (B Ｅ ) molar ratio (constituent unit (A) / constituent unit (B) Ｅ )) is a copolymer with a ratio of 10 / 90 to 90 / 10.

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