Polymer and molded article

Abstract

Provided is a polymer that includes a segment A and a segment B. The segment A has a glass transition temperature of 25°C or lower and contains a 2,3,3,3-tetrafluoropropene unit and a fluorine-containing monomer unit (excluding a 2,3,3,3-tetrafluoropropene unit and a trifluoroethylene unit). The segment B has a melting point of 50°C or higher.

Description

Polymers and Molded Articles

[0001] The present disclosure relates to polymers and molded articles.

[0002] Patent Document 1 describes a method for producing a fluorine-containing multi-segmented polymer, characterized in that, when at least two types of monomers having a radically polymerizable unsaturated bond are radically polymerized in the presence of a radical generating source and an iodide compound having iodine bonded to carbon, the monomers constituting the polymer chain segments are sequentially polymerized so as to form at least two types of polymer chain segments between the carbon-iodine bonds of the iodide compound, thereby obtaining a multi-segmented polymer in which at least one type of the polymer chain segments is a fluorine-containing polymer chain segment.

[0003] Patent Document 2 describes a polymer chain comprising a chain consisting of two or three types of polymer chain segments, an iodine atom present at one end of the chain, and a residue obtained by removing at least one iodine atom from an iodide compound present at the other end of the chain, wherein one type (when the chain consists of two types of polymer chain segments) or one or two types (when the chain consists of three types of polymer chain segments) of the polymer chain segments is an elastomeric polymer chain segment having a molecular weight of 30,000 to 1,200,000 selected from (1) vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene (molar ratio of 45 to 90:5 to 50:0 to 35) polymer and (2) perfluoro(alkyl vinyl ether) (the number of carbon atoms in the alkyl group is 1 to 3) / tetrafluoroethylene / vinylidene fluoride (molar ratio of 15 to 75:0 to 85 (excluding 0):0 to 85) polymer, The remainder of the polymer segments are non-elastomeric polymer chain segments having a molecular weight of 3,000 to 400,000 selected from (3) vinylidene fluoride / tetrafluoroethylene (molar ratio 0-100:0-100) polymers and (4) ethylene / tetrafluoroethylene (molar ratio 40-60:40-60) polymers, and the weight ratio of the elastomeric polymer chain segments to the non-elastomeric polymer chain segments is 40-95:5-60.

[0004] Patent Document 3 discloses a method for producing a compound of a radical polymerization initiator and a compound of the general formula RI ２ (wherein R is an alkylene group or a fluoroalkylene group having 3 or more carbon atoms), at a polymerization temperature of 0 to 50°C to produce a tetrafluoroethylene / propylene-based segment; and a second step of copolymerizing a second monomer component consisting mainly of tetrafluoroethylene and ethylene in the presence of the tetrafluoroethylene / propylene-based segment to bond the tetrafluoroethylene / ethylene-based segment to the tetrafluoroethylene / propylene-based segment.

[0005] Patent Document 4 describes thermoplastic block copolymers having trifluoroethylene units and further units different from vinylidene fluoride; or only trifluoroethylene units and vinylidene fluoride units; or trifluoroethylene units, vinylidene fluoride units and further units, and having xanthate or trithiocarbonate or monoiodinated end groups.

[0006] Japanese Patent Laid-Open No. 53-3495 Japanese Patent Publication No. 61-49327 Japanese Patent Laid-Open No. 2014-070206 Special Publication No. 2015-514854

[0007] An object of the present disclosure is to provide a polymer that can be easily molded and has excellent alkali resistance.

[0008] According to the present disclosure, there is provided a polymer comprising segment A and segment B, wherein segment A has a glass transition temperature of 25°C or lower and contains 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units), and segment B has a melting point of 50°C or higher.

[0009] According to the present disclosure, it is possible to provide a polymer that can be easily molded and has excellent alkali resistance.

[0010] Specific embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments.

[0011] (First Polymer) The first polymer of the present disclosure includes a segment A and a segment B. The first polymer may be a block polymer including a segment A and a segment B.

[0012] Conventionally, known block polymers are those comprising an elastomeric polymer chain segment and a non-elastomeric polymer chain segment, such as the fluorine-containing segmented polymer described in Patent Document 2. Patent Document 2 describes that the fluorine-containing segmented polymer comprising these segments has properties sufficient for practical use as a thermoplastic rubber, and that it can be molded by direct compression or other methods without vulcanization, similar to the case of fluorine-containing thermoplastic resins, and that the molded article has desirable elastomeric properties almost equivalent to those of vulcanized rubber.

[0013] However, no polymer is known that exhibits excellent flexibility, can be molded by molding methods that are generally used for thermoplastic resins, and has excellent alkali resistance.

[0014] It has been discovered that by constructing a polymer from two or more segments, at least one of which has a glass transition temperature of 25°C or lower, and further comprising 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units), and at least one of which has a melting point of 50°C, the resulting polymer exhibits excellent flexibility, can be molded by molding methods applied to general thermoplastic resins, and also exhibits excellent alkali resistance. The first polymer of the present disclosure was completed based on this finding.

[0015] The first polymer includes a segment A and a segment B. The first polymer will be described in detail below. As long as the first polymer includes a segment A and a segment B, it may also include another segment having a structure different from that of segment A and segment B.

[0016] (Segment A) Segment A has a glass transition temperature of 25° C. or lower. The glass transition temperature of segment A is preferably 0° C. or lower, more preferably −5° C. or lower, and even more preferably −10° C. or lower, and although there is no lower limit, it may be −40° C. or higher. Since the first polymer contains segment A having a glass transition temperature, it has excellent flexibility.

[0017] The glass transition temperature can be determined by using a differential scanning calorimeter (DSC822e manufactured by Mettler Toledo or X-DSC7000 manufactured by Hitachi High-Tech Science Corporation) to obtain a DSC curve by cooling 10 mg of a sample to −75° C. and then raising the temperature at 20° C. / min, and determining the temperature indicating the intersection point between an extension of the baseline before and after the second-order transition of the DSC curve and a tangent to the inflection point of the DSC curve as the glass transition temperature.

[0018] The heat of fusion of segment A is preferably less than 5 J / g, more preferably less than 3 J / g, and even more preferably less than 2 J / g, since this allows for further improvement in flexibility.

[0019] The heat of fusion can be calculated from the magnitude of the melting peak (ΔH) in the endothermic curve obtained by heating a sample from 30° C. to 220° C. at a rate of 10° C. / min using a differential scanning calorimetry (DSC) device. When a polymer does not show a clear melting peak, the polymer has no heat of fusion, i.e., the heat of fusion of the polymer is 0 J / g.

[0020] Segment A may be a segment that does not exhibit a distinct melting point.

[0021] Segment A contains 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units). The first polymer has a glass transition temperature, and since it contains segment A containing 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units, it has excellent flexibility and alkali resistance. Furthermore, since segment A contains 2,3,3,3-tetrafluoropropene units, the solvent solubility of the polymer in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide can be improved.

[0022] The fluorine-containing monomer that can constitute segment A is not particularly limited as long as it is a monomer other than 2,3,3,3-tetrafluoropropene and trifluoroethylene and contains a fluorine atom, and examples thereof include vinylidene fluoride [VdF], tetrafluoroethylene [TFE], hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, hexafluoroisobutene, and vinyl fluoride.

[0023] The fluorine-containing monomer that can constitute segment A is preferably at least one selected from the group consisting of VdF, TFE, hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), and chlorotrifluoroethylene, more preferably at least one selected from the group consisting of VdF and TFE, and even more preferably VdF. By containing VdF units in segment A, the glass transition temperature of segment A can be easily adjusted to fall within a desired range, thereby further improving flexibility. Furthermore, by containing VdF units in segment A, the solvent solubility of the polymer in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide can be improved.

[0024] The content of 2,3,3,3-tetrafluoropropene units in segment A is preferably 1 to 85 mol %, more preferably 6 mol % or more, even more preferably 12 mol % or more, still more preferably 18 mol % or more, particularly preferably 20 mol % or more, more preferably 78 mol % or less, even more preferably 50 mol % or less, still more preferably 40 mol % or less, and particularly preferably 30 mol % or less, based on all monomer units constituting segment A.

[0025] The content of the fluorine-containing monomer unit in segment A is preferably 99 to 15 mol%, more preferably 94 mol% or less, even more preferably 88 mol% or less, still more preferably 82 mol% or less, particularly preferably 78 mol% or less, more preferably 22 mol% or more, even more preferably 50 mol% or more, still more preferably 60 mol% or more, and particularly preferably 70 mol% or more, based on all monomer units constituting segment A.

[0026] The content of VdF units in segment A is preferably 99 to 15 mol%, more preferably 94 mol% or less, even more preferably 88 mol% or less, still more preferably 82 mol% or less, particularly preferably 78 mol% or less, more preferably 22 mol% or more, even more preferably 50 mol% or more, still more preferably 60 mol% or more, and particularly preferably 70 mol% or more, based on all monomer units constituting segment A.

[0027] Segment A may further contain a non-fluorine-containing monomer unit. Examples of the non-fluorine-containing monomer include ethylene, propylene, and alkyl vinyl ether. The content of the non-fluorine-containing monomer unit is preferably 0 to 50 mol %, more preferably 0 to 10 mol %, and even more preferably 0 to 1 mol %, relative to all monomer units constituting segment A, and may even be 0 mol %.

[0028] Segment A is a cyano group, a carboxyl group, an alkoxycarbonyl group, I, Br, -CH ２The segment A may further contain units based on a monomer having a reactive group such as OH or a carbon-carbon double bond. The content of units based on a monomer having a reactive group is preferably 0 to 50 mol %, more preferably 0 to 10 mol %, and even more preferably 0 to 1 mol %, relative to all monomer units constituting the segment A, and may be 0 mol %.

[0029] In the present disclosure, the content of each monomer unit can be measured by an NMR method.

[0030] In one embodiment, segment A can be formed by a 2,3,3,3-tetrafluoropropene / VdF copolymer or a 2,3,3,3-tetrafluoropropene / VdF / TFE copolymer.

[0031] In the 2,3,3,3-tetrafluoropropene / VdF copolymer, the composition (mol %) of 2,3,3,3-tetrafluoropropene units / VdF units is preferably (18 to 40) / (82 to 60), more preferably (20 to 30) / (80 to 70).

[0032] In the 2,3,3,3-tetrafluoropropene / VdF / TFE copolymer, the composition (mol %) of 2,3,3,3-tetrafluoropropene units / VdF units / TFE units is preferably (18 to 40) / (81 to 25) / (1 to 35), more preferably (20 to 40) / (75 to 30) / (5 to 30).

[0033] In one embodiment, segment A contains 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units), and the content of monomer units other than 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units is preferably 0 to 10 mol %, more preferably 0 to 2 mol %, even more preferably 0 to 1 mol %, still more preferably 0 to 0.1 mol %, and particularly preferably 0 mol %, based on all monomer units constituting segment A. The content of 2,3,3,3-tetrafluoropropene units and the content of fluorine-containing monomer units may be within the ranges described above.

[0034] In one embodiment, segment A contains 2,3,3,3-tetrafluoropropene units and VdF units, and the content of monomer units other than 2,3,3,3-tetrafluoropropene units and VdF units is preferably 0 to 10 mol %, more preferably 0 to 2 mol %, even more preferably 0 to 1 mol %, still more preferably 0 to 0.1 mol %, and particularly preferably 0 mol %, based on all monomer units constituting segment A. The content of 2,3,3,3-tetrafluoropropene units and the content of VdF units may be within the ranges described above.

[0035] (Segment B) Segment B has a melting point of 50°C or higher. The melting point of segment B is preferably 90°C or higher, more preferably 140°C or higher, and preferably 240°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. Since the first polymer contains segment B having a melting point in addition to segment A having a glass transition temperature, it has excellent flexibility and can be molded by molding methods applicable to general thermoplastic resins. In the present disclosure, "a polymer that can be easily molded" means that it can be molded by molding methods applicable to general thermoplastic resins, such as extrusion molding, injection molding, and compression molding.

[0036] The melting point can be determined by using a differential scanning calorimetry (DSC) device to raise the temperature of a sample from 30° C. to 220° C. at a rate of 10° C. / min, and measuring the temperature at the peak of the endothermic curve obtained.

[0037] Generally, the melting point of segment B is the same as the melting point of the first polymer, so the melting point of segment B in the first polymer can be determined by measuring the melting point of the first polymer.

[0038] The heat of fusion of segment B is preferably 5 J / g or more, more preferably 10 J / g or more, even more preferably 30 J / g or more, still more preferably 35 J / g or more, and preferably 90 J / g or less, more preferably 60 J / g or less, even more preferably 55 J / g or less.

[0039] The heat of fusion can be calculated from the magnitude of the melting peak (ΔH) of the endothermic curve obtained by heating a sample from 30° C. to 220° C. at a rate of 10° C. / min using a differential scanning calorimetry (DSC) device.

[0040] As long as segment B is formed from a polymer having a melting point, it may contain a fluorine-containing monomer unit or a non-fluorine-containing monomer unit. From the viewpoint of further improving the alkali resistance of the first polymer, segment B preferably contains a fluorine-containing monomer unit, and more preferably contains a fluorine-containing monomer unit (excluding trifluoroethylene units).

[0041] Examples of fluorine-containing monomers include vinylidene fluoride [VdF], tetrafluoroethylene [TFE], hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, hexafluoroisobutene, and vinyl fluoride.

[0042] The fluorine-containing monomer is preferably at least one selected from the group consisting of VdF, TFE, hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), and chlorotrifluoroethylene, more preferably at least one selected from the group consisting of VdF and TFE, and even more preferably VdF.

[0043] When the segment B has a VdF unit as the fluorine-containing monomer unit, the first polymer exhibits excellent flexibility and can be molded by a molding method applied to general thermoplastic resins, and also exhibits excellent alkali resistance and excellent solvent solubility in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide.

[0044] Segment B may contain, in addition to VdF units, other monomer units other than VdF. The other monomers may be either fluorine-containing or non-fluorine-containing monomers, and are preferably fluorine-containing monomers (excluding trifluoroethylene) or non-fluorine-containing monomers.

[0045] Examples of fluorine-containing monomers that can form segment B together with VdF include TFE, hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, hexafluoroisobutene, vinyl fluoride, and 2,3,3,3-tetrafluoropropene.

[0046] Examples of the fluorine-free monomer that can constitute the segment B together with VdF include ethylene and propylene.

[0047] Segment B may further contain units based on a monomer having a polar group such as a carbonyl group-containing group, an epoxy group, a hydroxy group, a sulfonic acid group, a sulfate group, a phosphate group, an amino group, an amide group, or an alkoxy group.

[0048] Examples of monomers having a polar group include hydroxyalkyl (meth)acrylates such as hydroxyethyl acrylate and 2-hydroxypropyl acrylate; unsaturated monobasic acids such as (meth)acrylic acid, crotonic acid, vinylacetic acid (3-butenoic acid), 3-pentenoic acid, 4-pentenoic acid, 3-hexenoic acid, and 4-heptenoic acid; unsaturated dibasic acids such as maleic acid, maleic anhydride, citraconic acid, and citraconic anhydride; alkylidene malonic acid esters such as dimethyl methylidene malonate; and vinyl carboxyalkyl ethers such as vinyl carboxymethyl ether and vinyl carboxyethyl ether. carboxyalkyl (meth)acrylates such as 2-carboxyethyl acrylate and 2-carboxyethyl methacrylate; (meth)acryloyloxyalkyl dicarboxylic acid esters such as acryloyloxyethyl succinate, methacryloyloxyethyl succinate, acryloyloxyethyl phthalate, acryloyloxypropyl succinate and methacryloyloxyethyl phthalate; monoesters of unsaturated dibasic acids such as maleic acid monomethyl ester, maleic acid monoethyl ester, citraconic acid monomethyl ester and citraconic acid monoethyl ester; and the like.

[0049] Among other monomers that can constitute segment B together with VdF, at least one selected from the group consisting of TFE, hexafluoropropylene, 2,3,3,3-tetrafluoropropene, and (meth)acrylic acid is preferred.

[0050] The content of VdF units in segment B is preferably 60 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and even more preferably 99 mol % or more, and may be 100 mol % or less, based on all monomer units constituting segment B, because this further improves the solubility in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide.

[0051] The content of other monomer units in segment B is preferably 40 mol % or less, more preferably 10 mol % or less, even more preferably 5 mol % or less, still more preferably 1 mol % or less, and may be 0 mol % or more, based on all monomer units constituting segment B, because this further improves the solubility in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide.

[0052] In one embodiment, segment B can be formed from a VdF homopolymer containing only VdF units, or a copolymer containing VdF units and at least one other monomer unit selected from the group consisting of TFE units, hexafluoropropylene units, 2,3,3,3-tetrafluoropropene units, and (meth)acrylic acid units.

[0053] In a copolymer containing VdF units and other monomer units, the composition (mol %) of VdF units / other monomer units is preferably 97.0 to 99.9 / 3.0 to 0.1.

[0054] As long as the first polymer contains a segment A and a segment B, it may also contain another segment C having a different structure from the segments A and B.

[0055] The first polymer may be a block polymer containing a chain structure represented by any of the following general formulas: General formula: A-B General formula: A-B-A General formula: B-A-B General formula: ABC General formula: BAC (wherein A represents segment A, B represents segment B, and C represents segment C).

[0056] The first polymer preferably contains a chain structure represented by general formula (1) or general formula (2) because it can further improve alkali resistance and is easy to produce. General formula (1): A-B-A General formula (2): B-A-B (wherein A represents segment A and B represents segment B).

[0057] In the first polymer, the mass ratio of segment A to segment B (A / B) is preferably 40 / 60 to 95 / 5, more preferably 50 / 50 or more, even more preferably 60 / 40 or more, and more preferably 90 / 10 or less, from the viewpoint of a balance between excellent flexibility and excellent alkali resistance.

[0058] The number average molecular weight (polystyrene equivalent) of the first polymer is preferably 20,000 to 1,500,000, more preferably 40,000 or more, even more preferably 70,000 or more, particularly preferably 140,000 or more, more preferably 1,400,000 or less, even more preferably 1,200,000 or less, and particularly preferably 1,100,000 or less. The number average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0059] The weight average molecular weight (polystyrene equivalent) of the first polymer is preferably 50,000 to 3,000,000, more preferably 80,000 or more, even more preferably 100,000 or more, still more preferably 200,000 or more, particularly preferably 500,000 or more, more preferably 2,400,000 or less, even more preferably 2,200,000 or less, and particularly preferably 2,000,000 or less. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0060] The first polymer of the present disclosure can be produced by, for example, the following production methods: (1) a method of preparing a polymer that forms segment B by polymerizing a monomer that can constitute segment B in the presence of a bromine compound or an iodine compound as a chain transfer agent, and preparing a polymer that forms segment A by polymerizing a monomer that can constitute segment A in the presence of the polymer that forms segment B; or (2) a method of preparing a polymer that forms segment A by polymerizing a monomer that can constitute segment A in the presence of a bromine compound or an iodine compound as a chain transfer agent, and preparing a polymer that forms segment B by polymerizing a monomer that can constitute segment B in the presence of the polymer that forms segment A.

[0061] When method (1) is used, a polymer is obtained in which segment A is bonded to both ends of a polymer chain forming segment B, i.e., a polymer containing a chain structure represented by general formula (1): A-B-A.

[0062] Furthermore, when method (2) is used, a polymer is obtained in which segment B is bonded to both ends of a polymer chain forming segment A, i.e., a polymer containing a chain structure represented by general formula (2): B-A-B.

[0063] In the methods (1) and (2), a bromine compound or an iodine compound is used as a chain transfer agent. By using a bromine compound or an iodine compound, an iodine atom or a bromine atom is introduced into the end of a polymer chain forming one segment, and functions as a binding site for another segment.

[0064] The polymerization method using a bromine compound or an iodine compound includes, for example, a method of emulsion polymerization in an aqueous medium under pressure in the presence of a bromine compound or an iodine compound in a substantially oxygen-free state (iodine transfer polymerization method). ８ I ｘ Br ｙ(wherein x and y are each an integer of 0 to 2 and satisfy 1≦x+y≦2; R ８ is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom).

[0065] Examples of iodine compounds include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 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 ３ , 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, monoiodomonobromo-substituted benzene, diiodomonobromo-substituted benzene, and (2-iodoethyl) and (2-bromoethyl) substituted benzenes, and these compounds may be used alone or in combination with each other.

[0066] Among these, it is preferable to use 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane in terms of polymerization reactivity, crosslinking reactivity, availability, and the like.

[0067] In the above-mentioned production method, the polymerization of the monomer is preferably carried out by emulsion polymerization. In one embodiment, the polymerization of the monomer is carried out in the presence of a polymerization initiator, a surfactant, and a solvent.

[0068] The polymerization initiator may be an oil-soluble radical polymerization initiator or a water-soluble radical initiator.

[0069] The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, for example, dialkyl peroxycarbonates such as diisopropyl peroxydicarbonate and disec-butyl peroxydicarbonate, peroxyesters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate, and dialkyl peroxides such as di-t-butyl peroxide, as well as di(ω-hydro-dodecafluoroheptanoyl) peroxide, di(ω-hydro-tetradecafluorooctanoyl) peroxide, di(ω-hydro-hexadecafluorononanoyl) peroxide, di(perfluorobutyryl) peroxide, di(perfluparyl) peroxide, di(perfluorohexanoyl) peroxide, di(perfluoroheptanoyl) peroxide, di(perfluorooctanoyl) peroxide, di(perfluorononanoyl) peroxide, di(ω-chloro- Representative examples include di[perfluoro(or fluorochloro)acyl]peroxides such as di(hexafluorobutyryl)peroxide, di(ω-chlorodecafluorohexanoyl)peroxide, di(ω-chlorotetradecafluorooctanoyl)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(tetrachloroundecafluorooctanoyl)peroxide, di(pentachlorotetradecafluorodecanoyl)peroxide, and di(undecachlorodotriacontafluorodocosanoyl)peroxide.

[0070] The water-soluble radical polymerization initiator may be a known water-soluble peroxide, such as ammonium salts, potassium salts, or sodium salts of persulfuric acid, perborate, perchloric acid, perphosphoric acid, or percarbonate, t-butyl permaleate, or t-butyl hydroperoxide. A reducing agent such as a sulfite may also be contained, and the amount used may be 0.1 to 20 times the amount of the peroxide.

[0071] The amount of polymerization initiator to be added is not particularly limited, but may be added all at once, stepwise, or continuously at the beginning of polymerization in an amount (for example, several ppm relative to water concentration) that does not significantly decrease the polymerization rate. The upper limit is within the range in which the heat of polymerization reaction can be removed from the equipment.

[0072] The surfactant may be a nonionic surfactant, an anionic surfactant, a cationic surfactant, etc. The amount added (relative to the solvent) is preferably 10 ppm by mass to 20% by mass, more preferably 10 ppm by mass to 10% by mass, still more preferably 10 to 5000 ppm by mass, and particularly preferably 50 to 5000 ppm by mass.

[0073] Furthermore, a polymerizable emulsifier may be used as the surfactant. The polymerizable emulsifier is not particularly limited as long as it is a compound having at least one unsaturated bond and at least one hydrophilic group. For example, ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COONH ４ , C.H. ２ =CFCF ２ CF (CF ３ ) OCF ２ CF ２ COONH ４ , C.F. ２ = CFOCF ２ CF (CF ３ ) OCF (CF ３ ) COONH ４ The amount added (relative to the solvent) is preferably 10 to 5000 ppm by mass, and more preferably 50 to 5000 ppm by mass.

[0074] The solvent is preferably one that does not have chain transfer properties, and examples of the solvent include water, a mixture of water and a water-soluble organic solvent, and a mixture of water and a water-insoluble organic solvent.

[0075] In the polymerization of the monomers, the polymerization temperature, polymerization pressure, and polymerization time vary depending on the type of solvent and polymerization initiator, but may be −15 to 150° C., atmospheric pressure to 12 MPa, and 1 to 24 hours. When an oil-soluble radical polymerization initiator is used as the polymerization initiator, the polymerization temperature is preferably 30 to 95° C. When a water-soluble radical polymerization initiator is used as the polymerization initiator, the polymerization temperature is preferably 0 to 100° C., and more preferably 10 to 95° C.

[0076] When the polymerization of the monomer is carried out by emulsion polymerization, an aqueous dispersion containing the polymer is obtained. In the above-mentioned production method, the polymer in the aqueous dispersion is coagulated, washed with water, dehydrated, and dried to obtain a polymer powder. The coagulation can be carried out by adding an inorganic salt such as aluminum sulfate or an inorganic acid to the dispersion, by applying mechanical shear force to the dispersion, or by freezing the dispersion.

[0077] The first polymer can also be produced by using at least 2,3,3,3-tetrafluoropropene as a monomer according to the methods described in Japanese Patent Application Laid-Open No. 53-3495 and Japanese Patent Application Laid-Open No. 61-49327.

[0078] (Second Polymer) The second polymer of the present disclosure is a polymer having a glass transition temperature and a melting point, containing 2,3,3,3-tetrafluoropropene units, and having a tetrahydrofuran extractable amount of 5 mass% or less at 25° C. The second polymer does not include polymers containing trifluoroethylene units.

[0079] As described above, no polymer is known that exhibits excellent flexibility, can be molded by molding methods that are generally used for thermoplastic resins, and has excellent alkali resistance.

[0080] It has been discovered that by selecting a polymer structure so that the polymer has a glass transition temperature and a melting point, introducing 2,3,3,3-tetrafluoropropene units into the polymer, and selecting a polymer structure so that the tetrahydrofuran extractable amount of the polymer at 25°C is 5% by mass or less, the resulting polymer exhibits excellent flexibility, can be molded by molding methods applied to general thermoplastic resins, and also exhibits excellent alkali resistance. The second polymer of the present disclosure has been completed based on this finding.

[0081] The glass transition temperature of the second polymer is preferably 25° C. or lower, more preferably 0° C. or lower, even more preferably −5° C. or lower, and even more preferably −10° C. or lower, and although there is no lower limit, it may be −40° C. or higher. Since the second polymer has a glass transition temperature, it has excellent flexibility.

[0082] The glass transition temperature can be determined by using a differential scanning calorimeter (DSC822e manufactured by Mettler Toledo or X-DSC7000 manufactured by Hitachi High-Tech Science Corporation) to obtain a DSC curve by cooling 10 mg of a sample to −75° C. and then raising the temperature at 20° C. / min, and determining the temperature indicating the intersection point between an extension of the baseline before and after the second-order transition of the DSC curve and a tangent to the inflection point of the DSC curve as the glass transition temperature.

[0083] The melting point of the second polymer is preferably 50° C. or higher, more preferably 90° C. or higher, even more preferably 140° C. or higher, and preferably 240° C. or lower, more preferably 220° C. or lower, and even more preferably 200° C. or lower. The second polymer has a melting point in addition to a glass transition temperature, and therefore has excellent flexibility and can be molded by molding methods that are applied to general thermoplastic resins.

[0084] The melting point can be determined by using a differential scanning calorimetry (DSC) device to raise the temperature of a sample from 30° C. to 220° C. at a rate of 10° C. / min, and measuring the temperature at the peak of the endothermic curve obtained.

[0085] The tetrahydrofuran extractable amount of the second polymer is 5% by mass or less, preferably 4% by mass or less, and more preferably 3% by mass or less. By setting the tetrahydrofuran extractable amount within the above numerical range, it is possible to impart flexibility to the polymer and also to impart excellent moldability to the polymer. The lower limit of the tetrahydrofuran extractable amount is not particularly limited, but may be 1% by mass or more or 2% by mass or more.

[0086] The amount of tetrahydrofuran extractables can be measured by a method in which the polymer is immersed in tetrahydrofuran at 25° C., and the filtered solution is dried and solidified.

[0087] The second polymer contains 2,3,3,3-tetrafluoropropene units. The second polymer has a glass transition temperature and a melting point, and because it contains 2,3,3,3-tetrafluoropropene units, it has excellent flexibility and alkali resistance.

[0088] The second polymer preferably contains a fluorine-containing monomer unit (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units). By introducing the fluorine-containing monomer unit into the polymer, the glass transition temperature and melting point of the polymer can be easily adjusted, and flexibility and alkali resistance can be further improved.

[0089] The fluorine-containing monomer that can constitute the second polymer is not particularly limited as long as it is a monomer other than 2,3,3,3-tetrafluoropropene and trifluoroethylene and contains a fluorine atom, and examples thereof include vinylidene fluoride [VdF], tetrafluoroethylene [TFE], hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, hexafluoroisobutene, and vinyl fluoride.

[0090] The fluorine-containing monomer that can constitute the second polymer is preferably at least one selected from the group consisting of VdF, TFE, hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), and chlorotrifluoroethylene, more preferably at least one selected from the group consisting of VdF and TFE, and even more preferably VdF.

[0091] The content of 2,3,3,3-tetrafluoropropene units in the second polymer is preferably 1 to 65 mol%, more preferably 5 mol% or more, even more preferably 9 mol% or more, still more preferably 12 mol% or more, particularly preferably 14 mol% or more, more preferably 62 mol% or less, even more preferably 40 mol% or less, still more preferably 32 mol% or less, and particularly preferably 24 mol% or less, based on all monomer units constituting the second polymer.

[0092] The content of the fluorine-containing monomer unit in the second polymer is preferably 99 to 35 mol%, more preferably 95 mol% or less, even more preferably 91 mol% or less, still more preferably 88 mol% or less, particularly preferably 86 mol% or less, more preferably 38 mol% or more, even more preferably 60 mol% or more, still more preferably 68 mol% or more, and particularly preferably 76 mol% or more, based on all monomer units constituting the second polymer.

[0093] When the second polymer contains a VdF unit as the fluorine-containing monomer unit, the second polymer exhibits excellent flexibility and can be molded by a molding method applied to general thermoplastic resins, and also exhibits better alkali resistance and better solvent solubility in solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide.

[0094] The content of VdF units in the second polymer is preferably 99 to 35 mol%, more preferably 95 mol% or less, even more preferably 91 mol% or less, still more preferably 88 mol% or less, particularly preferably 86 mol% or less, more preferably 38 mol% or more, even more preferably 60 mol% or more, still more preferably 68 mol% or more, and particularly preferably 76 mol% or more, based on the fact that the solvent solubility is further improved.

[0095] The second polymer may further contain a non-fluorine-containing monomer unit. Examples of the non-fluorine-containing monomer include ethylene, propylene, and alkyl vinyl ether. The content of the non-fluorine-containing monomer unit is preferably 0 to 40 mol %, more preferably 0 to 8 mol %, and even more preferably 0 to 1 mol %, relative to all monomer units constituting the second polymer, and may even be 0 mol %.

[0096] The second polymer may contain a cyano group, a carboxyl group, an alkoxycarbonyl group, I, Br, or —CH ２ The second polymer may further contain units based on a monomer having a reactive group such as OH or a carbon-carbon double bond. The content of units based on a monomer having a reactive group is preferably 0 to 10 mol %, more preferably 0 to 2 mol %, and even more preferably 0 to 1 mol %, relative to all monomer units constituting the second polymer, and may even be 0 mol %.

[0097] The second polymer may further contain units based on a monomer having a polar group such as a carbonyl group-containing group, an epoxy group, a hydroxy group, a sulfonic acid group, a sulfate group, a phosphate group, an amino group, an amide group, or an alkoxy group.

[0098] Examples of monomers having a polar group include hydroxyalkyl (meth)acrylates such as hydroxyethyl acrylate and 2-hydroxypropyl acrylate; unsaturated monobasic acids such as (meth)acrylic acid, crotonic acid, vinylacetic acid (3-butenoic acid), 3-pentenoic acid, 4-pentenoic acid, 3-hexenoic acid, and 4-heptenoic acid; unsaturated dibasic acids such as maleic acid, maleic anhydride, citraconic acid, and citraconic anhydride; alkylidene malonic acid esters such as dimethyl methylidene malonate; and vinyl carboxyalkyl ethers such as vinyl carboxymethyl ether and vinyl carboxyethyl ether. carboxyalkyl (meth)acrylates such as 2-carboxyethyl acrylate and 2-carboxyethyl methacrylate; (meth)acryloyloxyalkyl dicarboxylic acid esters such as acryloyloxyethyl succinate, methacryloyloxyethyl succinate, acryloyloxyethyl phthalate, acryloyloxypropyl succinate and methacryloyloxyethyl phthalate; monoesters of unsaturated dibasic acids such as maleic acid monomethyl ester, maleic acid monoethyl ester, citraconic acid monomethyl ester and citraconic acid monoethyl ester; and the like.

[0099] The content of units based on monomers having a polar group is preferably 0 to 10 mol %, more preferably 0 to 2 mol %, and even more preferably 0 to 1 mol %, relative to all monomer units constituting the second polymer, and may be 0 mol %.

[0100] In one embodiment, the second polymer contains 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units), and the content of monomer units other than 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units is preferably 0 to 10 mol %, more preferably 0 to 2 mol %, even more preferably 0 to 1 mol %, still more preferably 0 to 0.1 mol %, and particularly preferably 0 mol %, based on all monomer units constituting the second polymer. The content of 2,3,3,3-tetrafluoropropene units and the content of fluorine-containing monomer units may be within the ranges described above.

[0101] In one embodiment, the second polymer contains 2,3,3,3-tetrafluoropropene units and VdF units, and the content of monomer units other than 2,3,3,3-tetrafluoropropene units and VdF units is preferably 0 to 10 mol %, more preferably 0 to 2 mol %, even more preferably 0 to 1 mol %, still more preferably 0 to 0.1 mol %, and particularly preferably 0 mol %, based on all monomer units constituting the second polymer. The content of 2,3,3,3-tetrafluoropropene units and the content of VdF units may be within the ranges described above.

[0102] The number average molecular weight (polystyrene equivalent) of the second polymer is preferably 20,000 to 1,500,000, more preferably 40,000 or more, even more preferably 70,000 or more, particularly preferably 140,000 or more, more preferably 1,400,000 or less, even more preferably 1,200,000 or less, and particularly preferably 1,100,000 or less. The number average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0103] The weight average molecular weight (polystyrene equivalent) of the second polymer is preferably 50,000 to 3,000,000, more preferably 80,000 or more, even more preferably 100,000 or more, still more preferably 200,000 or more, particularly preferably 500,000 or more, more preferably 2,400,000 or less, even more preferably 2,200,000 or less, and particularly preferably 2,000,000 or less. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using dimethylformamide as a solvent.

[0104] The heat of fusion of the second polymer is preferably 1 J / g or more, more preferably 3 J / g or more, even more preferably 5 J / g or more, still more preferably 8 J / g or more, and preferably 40 J / g or less, more preferably 30 J / g or less, even more preferably 20 J / g or less.

[0105] In one embodiment, the second polymer contains two or more segments. By configuring the polymer with two or more segments, it is possible to easily impart a glass transition temperature and a melting point to the polymer, and it is also possible to easily adjust the glass transition temperature and the melting point of the polymer, thereby further improving flexibility and alkali resistance.

[0106] When the second polymer contains two or more segments, the configuration of each segment can be similar to the configuration of each segment of the first polymer. That is, the second polymer can contain Segment A and Segment B, like the first polymer, and can have a configuration similar to that of the first polymer. The first polymer can also have a configuration similar to that of the second polymer.

[0107] The second polymer of the present disclosure can be produced, for example, by the method described above as the method for producing the first polymer of the present disclosure.

[0108] A composition may be prepared by mixing the first polymer of the present disclosure or the second polymer of the present disclosure (hereinafter, the first polymer and the second polymer may be simply referred to as "polymers of the present disclosure") with other components. Examples of other components include fillers, plasticizers, processing aids, mold release agents, pigments, flame retardants, lubricants, light stabilizers, weather stabilizers, conductive agents, antistatic agents, UV absorbers, antioxidants, foaming agents, fragrances, oils, softening agents, and dehydrofluorination agents.

[0109] Furthermore, other polymers different from the polymers of the present disclosure can also be used as other components. Examples of other polymers include fluororesins, fluororubbers, and non-fluorine-containing polymers.

[0110] The polymers of the present disclosure or the compositions described above can also be molded to obtain molded articles.

[0111] The polymer of the present disclosure or the above-described composition can be molded by molding methods generally used for thermoplastic resins, such as injection molding, extrusion molding, compression molding, blow molding, transfer molding, roto-molding, and roto-lining molding.

[0112] In one embodiment, the polymer of the present disclosure exhibits good solvent solubility, and is highly soluble in solvents such as nitrogen-containing organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and dimethylformamide; ketone-based solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone; ester-based solvents such as ethyl acetate and butyl acetate; and ether-based solvents such as dioxane.

[0113] When the polymer of the present disclosure exhibits good solvent solubility, the polymer of the present disclosure can also be dissolved in a solvent and used as a coating material.

[0114] The polymer of the present disclosure or the above-described composition can also be used as a binder for forming an electrode for a battery.

[0115] Molded articles containing the polymers of the present disclosure have excellent flexibility and alkali resistance, and can therefore be used in a variety of applications.

[0116] The molded article can be used, for example, as a tube, a hose, a film, a covering material for electric wires, a roll, a flexible joint, a rubber plate, a belt, a damper, a valve, a valve seat, a valve body, a chemical-resistant coating material, a laminating material, a lining material, etc.

[0117] The molded articles can also be used as various sealing materials such as rings, packings, gaskets, diaphragms, oil seals, bearing seals, lip seals, plunger seals, door seals, face seals, gas delivery plate seals, wafer support seals, and barrel seals.

[0118] In particular, molded articles containing the polymers of the present disclosure have excellent flexibility and alkali resistance, and are therefore suitable for use in various components used in chemical solution supply equipment for semiconductor manufacturing and food processing equipment, such as piping, tubes, joints, valves, tanks, containers, chemical solution bags, pumps, filters, etc.

[0119] Molded articles containing the polymers of the present disclosure are also suitable for use as molded articles that come into contact with the human body.

[0120] Molded articles that come into contact with the human body do not need to be in constant contact like a watch strap, but may be in contact only when in use like a smartphone case. Furthermore, the entire surface of the molded article does not need to come into contact with the human body; only a portion of it may. Specific uses of such molded articles include the following:

[0121] (1) Interior parts for automobiles, motorcycles, ships, aircraft, bicycles, etc. Steering wheels, armrests, shift levers, seat covers, etc. (2) Wearables Smart watches, smart bands, smart glasses, VR (Virtual Reality) devices, body-attached devices, others (clothing-attached devices, ring-type devices), etc. (3) Eyeglasses parts Nose pads, tendons, etc. (4) Health goods Magnetic necklaces, magnetic bracelets, magnetic bandages such as Pip Elekiban (registered trademark), pelvic belts, supports, healing dolls, etc. (5) Sports goods Mats, shoes, underwater masks, snorkels, diving equipment, fishing equipment, golf club grips, etc. (6) Earphone parts, headphone parts Cables, ear hooks, ear pieces, ear pads, etc. (7) Electronic device covers Smartphone covers, tablet covers, keyboards (covers), etc. (8) Kitchen supplies (9) Pet supplies: toilet trays, food dishes, collars, etc. (10) Office supplies: pen grips, mice, mouse pads, etc. (11) Decorations: boots, rubber boots, insoles, hats, hair bands, raincoats, umbrella and cane grips, etc. (12) Other: buttons, wheelchair foil socks, bags, eyelash curlers, hearing aids, rubber accessories, non-magnetic rubber accessories for fashion use, robot exteriors, robot (flexible) cables, public bath locker keys, etc.

[0122] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0123] <1> According to a first aspect of the present disclosure, there is provided a polymer comprising Segment A and Segment B, wherein Segment A has a glass transition temperature of 25°C or less and contains 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units), and Segment B has a melting point of 50°C or more. <2> According to a second aspect of the present disclosure, there is provided a polymer according to the first aspect, which contains a chain structure represented by general formula (1) or general formula (2). General formula (1): A-B-A General formula (2): B-A-B (wherein A represents Segment A, and B represents Segment B.) <3> According to a third aspect of the present disclosure, there is provided a polymer according to the first or second aspect, wherein the fluorine-containing monomer units of Segment A are vinylidene fluoride units. <4> According to a fourth aspect of the present disclosure, there is provided a polymer according to any one of the first to third aspects, in which the content of 2,3,3,3-tetrafluoropropene units in Segment A is 18 mol % or more relative to all monomer units constituting Segment A. <5> According to a fifth aspect of the present disclosure, there is provided a polymer according to any one of the first to fourth aspects, in which Segment B contains vinylidene fluoride units, and the content of vinylidene fluoride units in Segment B is 90 mol % or more relative to all monomer units constituting Segment B. <6> According to a sixth aspect of the present disclosure, there is provided a polymer according to any one of the first to fifth aspects, in which Segment B contains only vinylidene fluoride units, or contains vinylidene fluoride units and at least one monomer unit selected from the group consisting of tetrafluoroethylene units, hexafluoropropylene units, 2,3,3,3-tetrafluoropropene units, and (meth)acrylic acid units. <7> According to a seventh aspect of the present disclosure, there is provided the polymer according to any one of the first to sixth aspects, wherein the mass ratio of segment A to segment B is 40 / 60 to 95 / 5.<8> According to an eighth aspect of the present disclosure, a polymerizable composition comprising a chain structure represented by general formula (1) or general formula (2): General formula (1): A-B-A General formula (2): B-A-B (wherein A represents segment A and B represents segment B) wherein segment A has a glass transition temperature of -10°C or lower, comprises 2,3,3,3-tetrafluoropropene units and vinylidene fluoride units, the content of the 2,3,3,3-tetrafluoropropene units in segment A being 18 to 30 mol% based on all monomer units constituting segment A, and the content of the vinylidene fluoride units in segment A being 70 to 82 mol% based on all monomer units constituting segment A, segment B has a melting point of 140 to 200°C, comprises vinylidene fluoride units, the content of the vinylidene fluoride units in segment B being 95 mol% or more based on all monomer units constituting segment B, A polymer according to any one of the first to seventh aspects is provided, wherein the mass ratio (A / B) of segment A to segment B in the polymer is 50 / 50 to 90 / 10, and the weight average molecular weight of the polymer is 500,000 to 2,000,000. <9> According to a ninth aspect of the present disclosure, there is provided a polymer (excluding polymers containing trifluoroethylene units) that has a glass transition temperature and a melting point, contains 2,3,3,3-tetrafluoropropene units, and has a tetrahydrofuran extractable amount at 25°C of 5% by mass or less. <10> According to a tenth aspect of the present disclosure, there is provided a polymer according to the ninth aspect, further containing vinylidene fluoride units. <11> According to an eleventh aspect of the present disclosure, there is provided a polymer according to the ninth or tenth aspect, which includes two or more segments.<12> According to a twelfth aspect of the present disclosure, there is provided a polymer according to any one of the ninth to eleventh aspects, having a glass transition temperature of -10°C or lower, a melting point of 140 to 200°C, containing 2,3,3,3-tetrafluoropropene units and vinylidene fluoride units, wherein the content of 2,3,3,3-tetrafluoropropene units is 12 to 24 mol% based on all monomer units constituting the polymer and the content of vinylidene fluoride units is 76 to 88 mol% based on all monomer units constituting the polymer, having a tetrahydrofuran extractable amount at 25°C of 2 to 4 mass%, and having a weight average molecular weight of 500,000 to 2,000,000. <13> According to a thirteenth aspect of the present disclosure, there is provided a molded article containing the polymer according to any one of the first to twelfth aspects.

[0124] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0125] (Polymerization Method) Polymers were polymerized according to the polymerization methods of the following synthesis examples. The obtained polymers were evaluated based on the following evaluation criteria.

[0126] (THF Extraction Amount) 9 g of tetrahydrofuran (THF) was added to 1 g of the polymer obtained in each Example, and the mixture was stirred using a stirrer at 25° C. After 24 hours, the solid content was filtered, the solution was evaporated to dryness, and the weight of the dried product was measured to calculate the extraction amount.

[0127] (Solvent Solubility) 9 g of N-methyl-2-pyrrolidone (NMP) was added to 1 g of the polymer obtained in each example and stirred using a stirrer. After 24 hours, it was confirmed that no residue remained, and the solubility was evaluated according to the following criteria: ◯: No residue remained ×: Residue remained

[0128] (Alkali Resistance) The polymers obtained in each example were compression molded to obtain sheet-like molded articles having a thickness of 2 mm. When the polymer had a melting point, compression molding was carried out at a temperature 20 to 40°C higher than the melting point of the polymer. When the polymer did not have a melting point, compression molding was carried out at 100°C. The molded articles were immersed in 1% by volume aqueous ammonia at 90°C for 72 hours, and then their weights were measured. The weight change rate before and after immersion was calculated according to the following formula, and evaluated according to the following criteria: Weight change rate (%) = [(weight of molded article after immersion) - (weight of molded article before immersion)] / (weight of molded article before immersion) x 100 Good: The weight change rate was 10% or less. Bad: The weight change rate was more than 10%.

[0129] (Composition Analysis) The polymer composition was measured by a solution NMR method. Measuring device: Varian VNMRS400 Resonance frequency: 376.04 (Sfrq) Pulse width: 30°

[0130] (Weight-average molecular weight (Mw)) Based on the results of measurement by GPC, the molecular weight was calculated using standard polystyrene as the standard. GPC apparatus: TOSOH HLC-8320GPC Columns: 1 SuperAW-H, 3 SuperAWM-H Developing solvent: dimethylformamide (DMF) Sample concentration: 0.05% by mass Measurement temperature: 40°C

[0131] (Glass Transition Temperature) A DSC curve was obtained by heating 10 mg of a sample at a rate of 20°C / min using a differential scanning calorimeter X-DSC7000 (manufactured by Hitachi High-Tech Science Corporation), and the glass transition temperature was determined as the temperature at the intersection of an extension of the baseline before and after the second-order transition of the DSC curve and a tangent to the inflection point of the DSC curve.

[0132] (Melting Point) Using a differential scanning calorimeter X-DSC7000 (manufactured by Hitachi High-Tech Science Corporation), a DSC curve was obtained by heating 10 mg of a sample at a rate of 10°C / min, and the temperature at the peak of the obtained endothermic curve was identified as the melting point, and the heat of fusion was calculated from the magnitude of the melting peak (ΔH) of the endothermic curve.

[0133] Example 1 (Production of BAB block polymer (wherein A represents segment A and B represents segment B)) (Step 1) 4000 ml of pure water and CH ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COONH ４ 0.8001 g of 50% aqueous solution, C ５ F １１ COONH ４ 24.021 g of a 50% aqueous solution was added and purged with nitrogen, then slightly pressurized with VdF. The temperature was adjusted to 80 ° C. while stirring at 400 rpm. VdF was injected up to 1.64 MPa, and a mixed monomer solution of VdF and 2,3,3,3-tetrafluoropropene (R1234yf) with a molar ratio of 77.2 / 22.8 was further injected up to 2.001 MPa. 0.16 g of ammonium persulfate dissolved in 4 ml of pure water was injected with nitrogen to start polymerization. When the mixed monomer solution reached 24 g, 1.009 g of 1,4-diiodoperfluorobutane was added. When the pressure dropped to 1.98 MPa, the mixed monomer solution was increased to 2.01 MPa, and this was repeated until 1020 g was charged. The gas in the autoclave was released to 0.05 MPa, and then heat treatment was carried out for 3 hours. A 10 g sample of the dispersion in the autoclave was taken and dried to obtain a polymer having a molar ratio of VdF / R1234yf=77.6 / 22.4, a glass transition temperature of −12.5° C., and no heat of fusion.

[0134] (Step 2) After the heat treatment in step 1, the autoclave was maintained at 80°C, and the pressure was increased to 2.003 MPa with VdF. A solution of 0.08 g of ammonium persulfate in 4 ml of pure water was then added with nitrogen to start polymerization. When the pressure dropped to 1.98 MPa, the pressure was increased to 2.01 MPa with VdF. This process was repeated until 180 g had been added. The gas in the autoclave was released and cooled, and 5,270 g of dispersion was recovered. The solid content of the dispersion was 23.83 wt%.

[0135] Aluminum sulfate was added to this dispersion to cause coagulation, followed by drying, yielding 1,250 g of polymer. The resulting block polymer had a molar ratio of VdF / R1234yf = 82.0 / 18.0, and the content of segment B calculated from the composition was 17.2 wt%. The weight-average molecular weight Mw was 1,266,000, the glass transition temperature was -12.9°C, the melting point was 160.3°C, and the heat of fusion was 8.2 mJ / mg.

[0136] Example 2 (Production of B-A-B block polymer (wherein A represents segment A and B represents segment B)) The same procedure as in Example 1 was followed, except that the amount of monomer mixture charged in step 1 was changed from 1020 g to 900 g, and the amount of VdF charged in step 2 was changed from 180 g to 300 g, and 5236 g of a dispersion was recovered. The solids content of the dispersion was 24.10 wt %.

[0137] Aluminum sulfate was added to this dispersion to cause coagulation, followed by drying, yielding 1,257 g of polymer. The resulting block polymer had a molar ratio of VdF / R1234yf = 84.2 / 15.8, and the content of segment B calculated from the composition was 28.1 wt%. The weight-average molecular weight Mw was 1,206,000, the glass transition temperature was -11.0°C, the melting point was 161.1°C, and the heat of fusion was 11.0 mJ / mg.

[0138] Example 3 (Production of B-A-B block polymer (wherein A represents segment A and B represents segment B)) The same procedure as in Example 1 was followed, except that the amount of monomer mixture charged in step 1 was changed from 1020 g to 780 g, and the amount of VdF charged in step 2 was changed from 180 g to 420 g, and 5252 g of a dispersion was recovered. The solids content of the dispersion was 23.74 wt %.

[0139] Aluminum sulfate was added to this dispersion to cause coagulation, followed by drying, yielding 1,250 g of polymer. The resulting block polymer had a molar ratio of VdF / R1234yf = 85.9 / 14.1, and the content of segment B calculated from the composition was 36.0 wt%. The weight-average molecular weight Mw was 1,614,000, the glass transition temperature was -11.2°C, the melting point was 161.4°C, and the heat of fusion was 17.1 mJ / mg.

[0140] Example 4 (Production of A-B-A block polymer (wherein A represents segment A and B represents segment B)) (Step 1) 4000 ml of pure water and CH ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COONH ４ 0.8003 g of 50% aqueous solution, C ５ F １１ COONH ４ 24.014 g of a 50% aqueous solution was added and purged with nitrogen. A slight pressure was applied using VdF. The temperature was adjusted to 80°C while stirring at 400 rpm, and VdF was injected up to 2.00 MPa. A solution of 0.16 g of ammonium persulfate in 4 ml of pure water was injected using nitrogen to start polymerization. When the pressure reached 24 g of VdF, 1.009 g of 1,4-diiodoperfluorobutane was added. When the pressure dropped to 1.98 MPa, the pressure was increased to 2.01 MPa using VdF. This process was repeated until 300 g was added. The gas in the autoclave was released to 0.05 MPa, and then the autoclave was heat-treated for 3 hours. A 10 g sample of the dispersion in the autoclave was taken and dried to obtain a polymer. The glass transition temperature of the resulting polymer was not observed. The melting point was 161.1°C, and the heat of fusion was 44.8 mJ / mg.

[0141] (Step 2) After the heat treatment in step 1, the autoclave was maintained at 80 ° C., and a mixed monomer solution of VdF and R1234yf in a molar ratio of 77.5 / 22.5 was added to the autoclave at 1.64 MPa and 2.001 MPa, respectively. A solution of 0.08 g of ammonium persulfate in 4 ml of pure water was added with nitrogen to initiate polymerization. When the pressure dropped to 1.98 MPa, the mixed monomer solution was added and the pressure was increased to 2.01 MPa. This process was repeated until 900 g had been added. The gas in the autoclave was released and cooled, and 5271 g of dispersion was recovered. The solids content of the dispersion was 23.80 wt %.

[0142] Aluminum sulfate was added to this dispersion to cause coagulation, followed by drying, yielding 1,248 g of polymer. The resulting block polymer had a molar ratio of VdF / R1234yf = 82.7 / 17.3, and the content of segment B calculated from the composition was 24.1 wt%. The weight-average molecular weight Mw was 1,426,000, the glass transition temperature was -10.4°C, the melting point was 160.8°C, and the heat of fusion was 10.8 mJ / mg.

[0143] Comparative Example 1 (Production of BAB block polymer (wherein A represents segment A and B represents segment B)) (Step 1) 4000 ml of pure water and CH ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COONH ４ 0.8001 g of 50% aqueous solution, C ５ F １１ COONH ４ 24.021 g of a 50% aqueous solution was added and substituted with nitrogen, and the pressure was slightly increased with hexafluoropropene (HFP). The temperature was adjusted to 80 ° C. while stirring at 400 rpm, and HFP was injected up to 0.68 MPa. A mixed monomer solution of VdF and HFP with a molar ratio of 78.3 / 21.7 was further injected up to 2.001 MPa. 0.16 g of ammonium persulfate dissolved in 4 ml of pure water was injected with nitrogen to start polymerization. When the mixed monomer solution reached 24 g, 1.003 g of 1,4-diiodoperfluorobutane was added. When the pressure dropped to 1.98 MPa, the mixed monomer solution was increased to 2.01 MPa, and this was repeated until 1020 g was charged. The gas in the autoclave was released to 0.05 MPa, and then heat treatment was carried out for 3 hours. A 10 g sample of the dispersion in the autoclave was taken and dried to obtain a polymer having a molar ratio of VdF / HFP=78.6 / 21.4.

[0144] (Step 2) After the heat treatment in step 1, the autoclave was maintained at 80°C, and the pressure was increased to 2.003 MPa with VdF. A solution of 0.08 g of ammonium persulfate in 4 ml of pure water was then added with nitrogen to start polymerization. When the pressure dropped to 1.98 MPa, the pressure was increased to 2.01 MPa with VdF. This process was repeated until 180 g had been added. The gas in the autoclave was released and cooled, and 5,275 g of dispersion was recovered. The solid content of the dispersion was 23.81 wt%.

[0145] Aluminum sulfate was added to this dispersion to cause coagulation, followed by drying to obtain 1245 g of polymer. The resulting block polymer had a molar ratio of VdF / HFP=82.5 / 17.5, and the content of segment B calculated from the composition was 14.8 wt%. The weight-average molecular weight Mw was 1,150,000, the glass transition temperature was -18.7°C, the melting point was 160.1°C, and the heat of fusion was 8.0 mJ / mg.

[0146] Comparative Example 2 According to the production method described in Example 12 of JP-A 2013-216915, a fluoroelastomer containing VdF and R1234yf in a molar ratio of 78.6 / 21.4 was obtained.

[0147] For Examples 1 to 4 and Comparative Examples 1 and 2, the alkali resistance, solvent solubility, and THF extraction tests were carried out, and the results are summarized in Table 1.

[0148]

Claims

1. A polymer comprising segment A and segment B, wherein segment A has a glass transition temperature of 25°C or lower and contains 2,3,3,3-tetrafluoropropene units and fluorine-containing monomer units (excluding 2,3,3,3-tetrafluoropropene units and trifluoroethylene units), and segment B has a melting point of 50°C or higher.

2. The polymer according to claim 1, which contains a chain structure represented by general formula (1) or general formula (2). General formula (1): A-B-A General formula (2): B-A-B (wherein A represents segment A and B represents segment B).

3. The polymer according to claim 1 or 2, wherein the fluorine-containing monomer unit of segment A is a vinylidene fluoride unit.

4. The polymer according to any one of claims 1 to 3, wherein the content of 2,3,3,3-tetrafluoropropene units in segment A is 18 mol % or more based on the total monomer units constituting segment A.

5. A polymer according to any one of claims 1 to 4, wherein segment B contains vinylidene fluoride units, and the content of vinylidene fluoride units in segment B is 90 mol % or more based on all monomer units constituting segment B.

6. The polymer according to any one of claims 1 to 5, wherein segment B contains only vinylidene fluoride units, or contains vinylidene fluoride units and at least one monomer unit selected from the group consisting of tetrafluoroethylene units, hexafluoropropylene units, 2,3,3,3-tetrafluoropropene units and (meth)acrylic acid units.

7. The polymer according to any one of claims 1 to 6, wherein the mass ratio of segment A to segment B is 40 / 60 to 95 / 5.

8. A polymer having a chain structure represented by general formula (1) or general formula (2), wherein general formula (1): A-B-A general formula (2): B-A-B (wherein A represents segment A and B represents segment B), segment A has a glass transition temperature of -10°C or lower, contains 2,3,3,3-tetrafluoropropene units and vinylidene fluoride units, the content of 2,3,3,3-tetrafluoropropene units in segment A is 18 to 30 mol% based on all monomer units constituting segment A, and the content of vinylidene fluoride units in segment A is 70 to 82 mol% based on all monomer units constituting segment A, segment B has a melting point of 140 to 200°C, contains vinylidene fluoride units, and the content of vinylidene fluoride units in segment B is 95 mol% or more based on all monomer units constituting segment B, The polymer according to any one of claims 1 to 7, wherein a mass ratio (A / B) of segment A to segment B in the polymer is 50 / 50 to 90 / 10, and a weight average molecular weight of the polymer is 500,000 to 2,000,000.

9. A polymer having a glass transition temperature and a melting point, containing 2,3,3,3-tetrafluoropropene units, and having a tetrahydrofuran extractable amount of 5 mass% or less at 25°C (excluding polymers containing trifluoroethylene units).

10. The polymer of claim 9 further comprising vinylidene fluoride units.

11. The polymer of claim 9 or 10 comprising two or more segments.

12. The polymer according to any one of claims 9 to 11, having a glass transition temperature of -10°C or lower, a melting point of 140 to 200°C, containing 2,3,3,3-tetrafluoropropene units and vinylidene fluoride units, the content of 2,3,3,3-tetrafluoropropene units being 12 to 24 mol% based on all monomer units constituting the polymer, and the content of vinylidene fluoride units being 76 to 88 mol% based on all monomer units constituting the polymer, the amount of tetrahydrofuran extractable at 25°C being 2 to 4 mass%, and the weight average molecular weight being 500,000 to 2,000,000.

13. A molded article comprising the polymer according to any one of claims 1 to 12.

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