Methods for manufacturing fluoropolymers, aqueous dispersions, and fluoropolymer compositions

Abstract

This invention provides a method for manufacturing a fluoropolymer that does not require an emulsifier even when using an aqueous medium with low environmental impact. The method involves polymerizing at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene, and vinylidene fluoride in an aqueous medium, in the presence of a first polymer containing units based on a compound represented by the following formula (1): CXY = CR 1 -L-R 2 ...(1) Where X and Y independently represent hydrogen atoms, halogen atoms or methyl groups, and R... 1 L represents hydrogen atoms, halogen atoms, or alkyl groups having 1 to 3 carbon atoms, and L represents -CO-O-*, -O-CO-*, or -O-, where * indicates a group with R. 2 The bonding position, R 2 It represents a cycloalkyl group, a monovalent aromatic hydrocarbon group, or an alkyl chain having 1 to 6 carbon atoms, wherein R 2 Alkyl groups with 1 to 6 carbon atoms may have ether-like oxygen atoms between their carbon-carbon bonds, R 2 Hydrogen atoms in cycloalkyl, monovalent aromatic hydrocarbon groups and alkyl groups with 1 to 6 carbon atoms can be replaced by halogen atoms.

Description

Technical Field

[0001] This invention relates to a method for manufacturing fluoropolymers, aqueous dispersions, and fluoropolymer compositions. Background Technology

[0002] Fluoropolymers such as ethylene / tetrafluoroethylene copolymers or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymers have excellent heat resistance, chemical resistance, flame retardancy, and weather resistance, and therefore have been used in various industrial fields for a long time.

[0003] As a method for manufacturing fluoropolymers, one example is the method of emulsion polymerization of fluorinated monomers in an aqueous medium using a fluorinated emulsifier (see Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2007 / 046377 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] Since Patent Document 1 uses an aqueous medium, it has a low environmental impact. However, since a large amount of emulsifier, which is an essential component, remains in the aqueous dispersion obtained by polymerization, the emulsifier must be removed depending on the application.

[0009] This invention provides a method for manufacturing fluoropolymers that do not require emulsifiers, even when using aqueous media with low environmental impact.

[0010] Technical solutions adopted to solve technical problems

[0011] Through in-depth research, the inventors have discovered that the above-mentioned technical problems can be solved by the following configuration.

[0012] [1] A method for manufacturing a fluoropolymer, wherein at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene, and vinylidene fluoride is polymerized in an aqueous medium in the presence of a first polymer containing units of a compound represented by the following formula (1):

[0013] CXY = CR 1 -LR 2 ···(1)

[0014] Where X and Y independently represent hydrogen atoms, halogen atoms, or methyl groups, and R... 1 L represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms; L represents -CO-O-*, -O-CO-*, or -O-; where * indicates a group with R. 2 The bonding position, R2 It represents a cycloalkyl group, a monovalent aromatic hydrocarbon group, or an alkyl chain having 1 to 6 carbon atoms, wherein R 2 Alkyl groups with 1 to 6 carbon atoms may have ether-like oxygen atoms between their carbon-carbon bonds, R 2 Hydrogen atoms in cycloalkyl, monovalent aromatic hydrocarbon groups and alkyl groups with 1 to 6 carbon atoms can be replaced by halogen atoms.

[0015] [2] The manufacturing method as described in [1], wherein the amount of the first polymer present is 0.0001 to 1 part by mass relative to 100 parts by mass of the aqueous medium.

[0016] [3] The manufacturing method as described in [1] or [2], wherein the first polymer present in the aqueous medium is composed of particles with a diameter of 10 to 1000 nm, which are accumulated in a volume-based manner of 50%.

[0017] [4] The manufacturing method as described in any one of [1] to [3], wherein the first polymer is a polymer obtained by polymerizing the compound represented by the compound represented by the formula (1) with 0.1 to 5.0 moles of a water-soluble polymerization initiator relative to 1 mole of the compound represented by the formula (1).

[0018] [5] A method for manufacturing a fluoropolymer, comprising polymerizing a compound represented by formula (1) in an aqueous medium to obtain an aqueous medium containing a first polymer, and then polymerizing at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene and vinylidene fluoride in the aqueous medium containing the first polymer to manufacture the fluoropolymer:

[0019] CXY = CR 1 -LR 2 ···(1)

[0020] Where X and Y independently represent hydrogen atoms, halogen atoms, or methyl groups, and R... 1 L represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms; L represents -CO-O-*, -O-CO-*, or -O-; where * indicates a group with R. 2 The bonding position, R 2 It represents a cycloalkyl group, a monovalent aromatic hydrocarbon group, or an alkyl chain having 1 to 6 carbon atoms, wherein R 2 Alkyl groups with 1 to 6 carbon atoms may have ether-like oxygen atoms between their carbon-carbon bonds, R 2 Hydrogen atoms in cycloalkyl, monovalent aromatic hydrocarbon groups and alkyl groups with 1 to 6 carbon atoms can be replaced by halogen atoms.

[0021] [6] The manufacturing method as described in [5], wherein the aqueous medium in which the first polymer is present is an aqueous medium used to manufacture the first polymer so that the first polymer is present.

[0022] [7] The manufacturing method as described in [5] or [6], wherein the compound represented by formula (1) is polymerized by using 0.1 to 5 moles of a water-soluble polymerization initiator relative to 1 mole of the compound represented by formula (1).

[0023] [8] The manufacturing method as described in any one of [5] to [7], wherein, during the polymerization of the fluorinated monomer, the amount of the first polymer present is 0.0001 to 1.0 parts by mass relative to 100 parts by mass of the aqueous medium.

[0024] [9] An aqueous dispersion of a fluoropolymer, comprising:

[0025] Aqueous media;

[0026] The fluoropolymer contains a volume-based cumulative 50% of particles with a diameter of 20–3000 nm, wherein the fluoropolymer contains units based on at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene, and vinylidene fluoride; and

[0027] A first polymer containing units of a compound represented by formula (1) is contained as particles in the aqueous medium or in particles containing the fluoropolymer:

[0028] CXY = CR 1 -LR 2 ···(1)

[0029] Where X and Y independently represent hydrogen atoms, halogen atoms, or methyl groups, and R... 1 L represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms; L represents -CO-O-*, -O-CO-*, or -O-; where * indicates a group with R. 2 The bonding position, R 2 It represents a cycloalkyl group, a monovalent aromatic hydrocarbon group, or an alkyl chain having 1 to 6 carbon atoms, wherein R 2 Alkyl groups with 1 to 6 carbon atoms may have ether-like oxygen atoms between their carbon-carbon bonds, R 2 Hydrogen atoms in cycloalkyl, monovalent aromatic hydrocarbon groups and alkyl groups with 1 to 6 carbon atoms can be replaced by halogen atoms.

[0030]

[10] The aqueous dispersion of the fluoropolymer as described in [9] contains 1.0 to 50.0 parts by mass of particles containing the fluoropolymer relative to 100 parts by mass of the aqueous medium.

[0031]

[11] An aqueous dispersion of a fluoropolymer as described in [9] or

[10] , wherein 100 parts by mass of the aqueous medium contain 0.0001 to 1.0 parts by mass of particles of the first polymer.

[0032]

[12] An aqueous dispersion of a fluoropolymer as described in any one of [9] to

[11] , wherein the dispersion comprises 0.001 to 5.00 parts by mass of the particles of the first polymer relative to 100 parts by mass of the particles containing the fluoropolymer.

[0033]

[13] An aqueous dispersion of a fluoropolymer as described in any one of [9] to

[12] , wherein the particles of the first polymer are particles with a cumulative diameter of 10 to 1000 nm on a volume basis of 50%.

[0034]

[14] A polymer composition comprising:

[0035] A first polymer containing units of a compound represented by formula (1); and

[0036] Fluoropolymers containing units based on at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene, and vinylidene fluoride.

[0037] The polymer composition exhibits infrared absorption in the range of 1500–1800 cm⁻¹. -1 The peaks at the location are derived from units of compounds represented by the following formula (1):

[0038] CXY = CR 1 -LR 2 ···(1)

[0039] Where X and Y independently represent hydrogen atoms, halogen atoms, or methyl groups, and R... 1 L represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms; L represents -CO-O-*, -O-CO-*, or -O-; where * indicates a group with R. 2 The bonding position, R 2 It represents a cycloalkyl group, a monovalent aromatic hydrocarbon group, or an alkyl chain having 1 to 6 carbon atoms, wherein R 2 Alkyl groups with 1 to 6 carbon atoms may have ether-like oxygen atoms between their carbon-carbon bonds, R 2 Hydrogen atoms in cycloalkyl, monovalent aromatic hydrocarbon groups and alkyl groups with 1 to 6 carbon atoms can be replaced by halogen atoms.

[0040]

[15] The polymer composition as described in

[14] , wherein the first polymer is present in an amount of 0.001 to 5.00 parts by mass relative to 100 parts by mass of the fluoropolymer.

[0041] Invention Effects

[0042] According to the present invention, a method for manufacturing a fluoropolymer that does not require an emulsifier even when using an aqueous medium with low environmental impact can be provided. Detailed Implementation

[0043] The meanings of the terms used in this invention are as follows.

[0044] A "unit" refers to the collective term for atomic clusters derived directly from a single monomer molecule, formed directly from the polymerization of monomers. The content (mass%) of each unit relative to all units contained in the polymer can be determined by analyzing the polymer using solid-state nuclear magnetic resonance (NMR) or estimated from the amount of each monomer added. Generally, the content of each unit calculated from the amount of each monomer added is approximately the same as the actual content of each unit.

[0045] "Volume-based cumulative 50% diameter" refers to the particle size at the point on the cumulative curve where the cumulative volume reaches 50%, obtained by measuring particle size distribution using laser diffraction and scattering with the total volume of the particle cluster as 100%. It is also hereinafter referred to as "D50".

[0046] The "peaks of the infrared absorption spectrum" were determined using an infrared spectrophotometer (ThemoFisher SCIENTIFIC) on a 100 μm thick film obtained by press-forming a composition containing a fluoropolymer.

[0047] The method for manufacturing the fluoropolymer of the present invention is a method of polymerizing at least one fluorinated monomer (hereinafter also referred to as "specific polymer") selected from tetrafluoroethylene, trifluorochloroethylene and vinylidene fluoride in an aqueous medium in the presence of a first polymer (hereinafter also referred to as "compound (1)") containing a unit based on the compound represented by the following formula (1).

[0048] The method for manufacturing the fluoropolymer of the present invention can use a specific polymer obtained by further polymerization, or it can polymerize the specific polymer in an aqueous medium and then polymerize the specific fluorinated monomer in the same polymerization system. Polymerization in the same polymerization system means using an aqueous medium used to manufacture the specific polymer, in which the specific polymer is present, and polymerizing the specific fluorinated monomer in this aqueous medium containing the specific polymer. The specific polymer obtained by further polymerization can be a commercially available product.

[0049] As a method for manufacturing the fluoropolymer of the present invention, it is preferable to polymerize compound (1) in an aqueous medium to obtain an aqueous medium containing a specific polymer, and then polymerize a specific fluorinated monomer in the aqueous medium containing the specific polymer to manufacture the fluoropolymer. In this two-stage manufacturing method, the stage of obtaining the aqueous medium containing the specific polymer in the previous stage will be referred to as "step 1", and the stage of manufacturing the fluoropolymer in the next stage will be referred to as "step 2".

[0050] The polymerization of compound (1) in step 1 and the polymerization of the specific fluorinated monomer in step 2 are preferably carried out in the presence of a polymerization initiator. A water-soluble polymerization initiator is preferred as the polymerization initiator.

[0051] <Process 1>

[0052] In step 1, compound (1) can be used in combination of two or more types.

[0053] CXY = CR 1 -LR 2 ···(1)

[0054] Where X and Y independently represent hydrogen atoms, halogen atoms, or methyl groups, and R... 1 L represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms; L represents -CO-O-*, -O-CO-*, or -O-; where * indicates a group with R. 2 The bonding position, R 2 It represents a cycloalkyl group, a monovalent aromatic hydrocarbon group, or an alkyl chain having 1 to 6 carbon atoms, wherein R 2 Alkyl groups with 1 to 6 carbon atoms may have ether-like oxygen atoms between their carbon-carbon bonds, R 2 Hydrogen atoms in cycloalkyl, monovalent aromatic hydrocarbon groups and alkyl groups with 1 to 6 carbon atoms can be replaced by halogen atoms.

[0055] As R 2 Cycloalkyl groups, such as cyclobutyl, cyclopentyl, and cyclohexyl, can be listed. As monovalent aromatic hydrocarbon groups, phenyl and naphthyl can be listed. As alkyl groups having 1 to 6 carbon atoms, methyl, ethyl, n-propyl, isopropyl, n-butyl, and isobutyl can be listed.

[0056] From the perspective of easily obtaining a specific polymer, each group in formula (1) is preferably the group shown below.

[0057] X and Y are preferably hydrogen atoms, fluorine atoms, or chlorine atoms that are independent of each other, and more preferably both are hydrogen atoms.

[0058] As R 1 Preferably, it is an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group.

[0059] As for L, -CO-O-* and -O-CO-* are preferred, with -CO-O-* being particularly preferred.

[0060] As R 2 Cyclohexyl, phenyl, alkyl groups with 1 to 4 carbon atoms, fluoroalkyl groups with 1 to 4 carbon atoms, and alkyl groups with 2 to 5 carbon atoms having ether oxygen atoms between carbon-carbon bonds are particularly preferred. Alkyl groups with 1 to 4 carbon atoms and fluoroalkyl groups with 1 to 4 carbon atoms are particularly preferred.

[0061] As the compound represented by formula (1), the compound represented by formula (1-1) is preferred.

[0062] CH2=C(CH3)-CO-OR 21 ···(1-1)

[0063] Among them, R 21 It can be cyclohexyl, phenyl, alkyl chain with 1 to 4 carbon atoms, fluoroalkyl chain with 1 to 4 carbon atoms, or alkyl chain with 2 to 3 carbon atoms having ether oxygen atoms between carbon-carbon bonds.

[0064] As R 21 Preferably, the alkyl group having 1 to 4 carbon atoms and the fluoroalkyl group having 1 to 4 carbon atoms are used.

[0065] (Aqueous medium)

[0066] Examples of aqueous media include water and mixtures of water and water-soluble organic solvents.

[0067] Examples of water-soluble organic solvents include tert-butanol, propylene glycol, and dipropylene glycol. In the case of a mixture of water and a water-soluble organic solvent, the concentration of the water-soluble organic solvent is preferably 10% by mass or less. As an aqueous medium, water alone is preferred.

[0068] (Water-soluble polymerization initiator)

[0069] As water-soluble polymerization initiators, water-soluble free radical initiators and water-soluble redox catalysts are preferred.

[0070] As water-soluble free radical initiators, persulfates such as ammonium persulfate and potassium persulfate, and water-soluble organic peroxides such as disuccinic acid peroxide, diglutaric acid peroxide, and tert-butyl hydroperoxide are preferred.

[0071] As a water-soluble redox catalyst, a combination of oxidants such as bromic acid or its salts, chloric acid or its salts, persulfate or its salts, permanganate or its salts, and hydrogen peroxide with reducing agents such as sulfurous acid or its salts, bisulfite or its salts, thiosulfate or its salts, organic acids, and inorganic salts is preferred. Potassium persulfate and ammonium persulfate are preferred as persulfates. Sodium sulfite is preferred as a sulfite. Combinations of sulfate anions, sulfite anions, chlorate anions, and metal ions can be included as inorganic salts. Transition metal ions are preferred, including ions of manganese, iron, cobalt, nickel, copper, zinc, cerium, and silver, with iron ions being more preferred. Ferric(II) sulfate is preferred as an inorganic salt.

[0072] As a water-soluble polymerization initiator, a water-soluble redox catalyst is preferred, and more preferably a combination of potassium persulfate and sodium sulfite, a combination of potassium persulfate, sodium sulfite and an inorganic salt, and even more preferably a combination of potassium persulfate and sodium sulfite and a combination of potassium persulfate, sodium sulfite and ferric sulfate (II).

[0073] Furthermore, considering the ease of polymerization of compound (1), the pH of the reaction system is preferably set to 3–10, or 6–8. To adjust this, sulfites such as sodium sulfite, ammonia, sodium hydroxide, hydrochloric acid, etc., can be added as needed.

[0074] Two or more water-soluble polymerization initiators can also be used in combination. Furthermore, as a method of adding water-soluble polymerization initiators, they can be added to the reaction system in their entirety before the polymerization reaction begins, or they can be added to the reaction system continuously or intermittently.

[0075] The amount of compound (1) used is preferably 0.0001 to 1.0 parts by mass relative to 100 parts by mass of the aqueous medium, more preferably 0.001 to 0.5 parts by mass. Within this range, not only can a decrease in the polymerization rate be prevented, but also the amount of a specific polymer that is mixed with the fluoropolymer can be reduced when manufacturing the fluoropolymer in step 2. In addition, as a method of adding compound (1), it is preferable to add it all at once in the initial stage before the polymerization reaction begins.

[0076] The amount of water-soluble polymerization initiator used relative to 1 mole of compound (1) is preferably 0.1 to 5.0 moles, more preferably 0.1 to 2.0 moles, even more preferably 0.1 to 1.5 moles, and particularly preferably 0.2 to 1.0 moles.

[0077] The polymerization temperature of compound (1) is preferably 10–95°C, more preferably 50–90°C. The polymerization time is preferably 5–400 minutes, more preferably 5–300 minutes, in the case of batch processing. The pressure conditions during polymerization are preferably reduced pressure or atmospheric pressure.

[0078] The above polymerization process yields an aqueous dispersion containing a specific polymer. The specific polymer is uniformly dispersed in the aqueous medium in particulate form. The aqueous dispersion is in a colloidal state.

[0079] It is hypothesized that specific polymer particles (hereinafter also referred to as "specific particles") introduce specific fluorinated monomers into the polymerization process of these monomers via their hydrophobic portions, thereby making the specific fluorinated monomers soluble. The addition of an initiator then facilitates the polymerization of the specific fluorinated monomers within the specific particles. It is also hypothesized that specific particles contribute to dispersion stabilization in aqueous media and organic solvents.

[0080] The D50 of a specific particle is preferably 10-1000 nm, more preferably 10-300 nm, even more preferably 10-200 nm, and particularly preferably 10-150 nm.

[0081] The specific particles are composed of polymers containing units based on compound (1).

[0082] The content of the compound (1)-based unit in the polymer is preferably 50% by mass or more, more preferably 70% by mass or more, and more preferably 90% by mass or more, relative to all units of the polymer. As an upper limit, 100% by mass can be listed.

[0083] Through the above polymerization, an aqueous dispersion of a fluoropolymer containing 0.0001 to 1.0 parts by mass of specific particles with a D50 of 10 to 1000 nm relative to 100 parts by mass of an aqueous medium can be readily obtained. The specific particles contained are preferably 0.005 to 0.5 parts by mass relative to 100 parts by mass of the aqueous medium, more preferably 0.002 to 0.1 parts by mass.

[0084] <Process 2>

[0085] Step 2 is a method for manufacturing a fluoropolymer by polymerizing at least one fluorinated monomer (i.e., a specific fluorinated monomer) selected from tetrafluoroethylene, trifluorochloroethylene and vinylidene fluoride in an aqueous medium containing a specific polymer obtained from Step 1.

[0086] The polymerization of a specific fluorinated monomer is preferably carried out using a water-soluble polymerization initiator. Examples of such water-soluble polymerization initiators include those described in step 1. Furthermore, the polymerization of the specific fluorinated monomer is also preferably carried out using a chain transfer agent.

[0087] Fluoropolymers include tetrafluoroethylene polymers containing tetrafluoroethylene (TFE)-based units (hereinafter also referred to as "TFE units"), polyvinylidene fluoride (hereinafter also referred to as "PVdF"), polychlorotrifluoroethylene, and copolymers of ethylene and chlorotrifluoroethylene. Among these, tetrafluoroethylene polymers are preferred.

[0088] In fluoropolymers, monomers other than specific fluorinated monomers can also be copolymerized.

[0089] Other monomers, and fluorinated monomers, include hexafluoropropylene (hereinafter also referred to as "HFP"), perfluoro(alkyl vinyl ether) (hereinafter also referred to as "PAVE"), and fluoroalkyl vinyl ether (hereinafter also referred to as "FAE").

[0090] As PAVE, examples include CF2 = CFOCF3 (hereinafter also referred to as "PMVE"), CF2 = CFOCF2CF3, CF2 = CFOCF2CF2CF3 (hereinafter also referred to as "PPVE"), CF2 = CFOCF2CF2CF2CF3, and CF2 = CFO(CF2)8F, with PMVE and PPVE being preferred.

[0091] As FAEs, CH2=CH(CF2)2F (hereinafter also referred to as "PFEE"), CH2=CH(CF2)3F, CH2=CH(CF2)4F (hereinafter also referred to as "PFBE"), CH2=CF(CF2)3H, and CH2=CF(CF2)4H can be listed, with PFEE and PFBE being preferred.

[0092] In addition, other monomers that can be listed include ethylene, propylene, vinyl chloride, vinylidene chloride, and vinyl fluoride.

[0093] In addition, monomers having oxygen-containing polar groups can also be listed as other monomers. Preferably, the oxygen-containing polar group is a hydroxyl group, a carbonyl group, an acetal group, or an oxocyclic alkane group; more preferably, an anhydride residue is preferred. Among monomers having an anhydride residue, monomers having cyclic anhydride residues are preferred, including itaconic anhydride (hereinafter also referred to as "IAH"), citraconic anhydride, 5-norbornene-2,3-dicarboxylic anhydride (also known as nadic anhydride, hereinafter also referred to as "NAH"), and maleic anhydride.

[0094] Examples of tetrafluoroethylene polymers include copolymers of TFE and PAVE, copolymers of TFE and HFP (hereinafter also referred to as "FEP"), copolymers of TFE and ethylene (hereinafter also referred to as "ETFE"), copolymers of TFE and propylene, and copolymers of TFE and vinylidene fluoride.

[0095] However, the tetrafluoroethylene polymers of the present invention do not include the specific high heat-resistant polymers described below.

[0096] Specific high heat-resistant polymers: polymers whose initial endothermic peak is at least 340°C or higher when heated by differential scanning calorimetry at a rate of 10°C / min, and whose endothermic peak is at least 340°C or higher after the initial endothermic peak.

[0097] The tetrafluoroethylene polymers of the present invention have melt-forming properties or elasticity.

[0098] As the tetrafluoroethylene polymers of the present invention, ETFE, PFA and FEP are preferred, with ETFE and PFA, which will be described later, being particularly preferred.

[0099] As a FEP, it is preferred that the proportion of HFP units to the total proportion of TFE units and HFP units is 1 to 15 mol%, and more preferably 5 to 13 mol%.

[0100] ETFE has TFE units and ethylene-based units (hereinafter also referred to as "E units"). In copolymers having TFE units and E units, the proportion of E units relative to the total of E units and TFE units is preferably 20 to 70 mol%, more preferably 25 to 60 mol%, and particularly preferably 35 to 55 mol%.

[0101] The total proportion of E units and TFE units relative to all units constituting ETFE is preferably 80 mol% or more, more preferably 85 mol% or more, and more preferably 90 mol% or more.

[0102] In addition to the E unit and the TFE unit, it is preferable to also have a FAE unit. The proportion of the FAE unit relative to the total of the E unit and the TFE unit is preferably 0.1 to 10 mol%, more preferably 0.1 to 5 mol%, and particularly preferably 0.2 to 4 mol%.

[0103] In addition to the E unit and TFE unit, it is preferable to also contain monomer units having oxygen-containing polar groups. The proportion of monomer units having oxygen-containing polar groups relative to the total of E units and TFE units is preferably 0.01 to 5 mol%, more preferably 0.05 to 3 mol%. Although the method for manufacturing the fluoropolymer of the present invention uses emulsion polymerization in an aqueous medium, even when using monomers with oxygen-containing polar groups, such as monomers with highly hydrophilic monomers having cyclic anhydride residues, excessive dissolution is avoided, and copolymerization with tetrafluoroethylene and the like is easily achieved, allowing for the easy introduction of oxygen-containing polar groups into the fluoropolymer.

[0104] The copolymer of TFE and PAVE has TFE units and PAVE units. As a copolymer of TFE and PAVE, it is preferred that the proportion of PAVE units to the total proportion of TFE units and PAVE units is more than 0.1 mol% and less than 20 mol% (hereinafter also referred to as "PF1"), and the proportion of PAVE units is 20 to 70 mol% (hereinafter also referred to as "PF2").

[0105] In PF1, the proportion of PAVE units relative to the total of TFE units and PAVE units is preferably 0.5 to 10 mol%, more preferably 0.5 to 5.0 mol%.

[0106] PF1 can be a copolymer consisting solely of TFE and PAVE units, or it may also contain one or more units based on other monomers. Other monomers are preferably other fluorinated monomers or monomers having oxygen-containing polar groups. Hexafluoropropylene is preferably a preferred other fluorinated monomer. NAH is preferably a monomer having oxygen-containing polar groups.

[0107] When the unit also includes units based on other monomers, the proportion of other fluorinated monomers relative to the total of the TFE unit and the PAVE unit is preferably 0.1 to 10 mol%, more preferably 0.1 to 6 mol%. The monomer having an oxygen-containing polar group is preferably 0.01 to 5 mol%, more preferably 0.05 to 3 mol%.

[0108] The total proportion of TFE units and PAVE units relative to all units constituting PF1 is preferably 80 mol% or more, more preferably 85 mol% or more, and more preferably 90 mol% or more.

[0109] Additionally, PF1 and below are also referred to as "PFA".

[0110] In PF2, the proportion of PAVE units relative to the total of TFE units and PAVE units is preferably 20-50 mol%, more preferably 25-45 mol%.

[0111] In addition to the TFE unit and the PAVE unit, it is preferable to also contain a unit based on a monomer having fluorine atoms and nitrile groups (hereinafter also referred to as "CN unit") and a unit based on a monomer having fluorine atoms and multiple vinyl groups (hereinafter also referred to as "DV unit").

[0112] As monomers with fluorine atoms and nitrile groups, examples include CF2=CFO(CF2)5CN and CF2=CFOCF2CF(CF3)CF2CF2CN.

[0113] Examples of monomers containing fluorine atoms and multiple vinyl groups include CF2=CFO(CF2)3OCF=CF2, CF2=CFO(CF2)4OCF=CF2, and CH2=CH(CF2)6CH=CH2.

[0114] The proportion of CN units relative to the total of TFE units and PAVE units is preferably 0.1 to 10.0 mol%, more preferably 0.5 to 5.0 mol%.

[0115] The ratio of DV units to the total of TFE units and PAVE units is preferably 0.01 to 1.0 mol%, more preferably 0.01 to 0.5 mol%.

[0116] The total proportion of TFE units and PAVE units relative to all units constituting PF2 is preferably 80 mol% or more, more preferably 85 mol% or more, and more preferably 90 mol% or more.

[0117] Specific fluorinated monomers and other monomers are added to the reaction system (i.e., the polymerization reactor) using conventional methods. For example, TFE is added to the reaction system continuously or intermittently to bring the polymerization pressure to a specified level. Alternatively, other monomers are dissolved in an aqueous medium, and the resulting solution is added to the reaction system continuously or intermittently.

[0118] When using water-soluble polymerization initiators, the water-soluble polymerization initiators can be added to the reaction system all at once or in batches.

[0119] When using a chain transfer agent, alcohols, hydrocarbons, and hydrofluorocarbons are preferred as chain transfer agents, considering their effect on stabilizing the resin terminal structure; alcohols and hydrocarbons are even more preferred. As alcohols, methanol and ethanol are preferred, considering their easy solubility in water and ease of separation from the copolymer after manufacturing. As hydrocarbons, n-pentane, cyclohexane, methane, and propane are preferred, as they offer good thermal stability and high chain transferability when introduced into the resin terminal structure.

[0120] The polymerization temperature is preferably 10–95°C, more preferably 15–90°C. The polymerization pressure is preferably 0.5–4.0 MPa, more preferably 0.6–3.5 MPa. The polymerization time, in the case of batch processing, is preferably 90–1000 minutes, more preferably 90–700 minutes.

[0121] Furthermore, the manufacture of specific polymers and fluoropolymers can be carried out continuously within the same polymerization reactor.

[0122] Furthermore, in the manufacturing method of the present invention, it is sufficient to form specific particles during the manufacturing of a specific polymer, or the manufacturing of a fluoropolymer can be carried out before compound (1) is completely consumed during the manufacturing of the specific polymer. In this case, it is considered that a fluoropolymer containing units based on compound (1) may be formed.

[0123] When the manufacture of a specific polymer and the manufacture of a fluoropolymer are carried out continuously, the specific polymer obtained from step 1 and present in step 2 is preferably 0.0001 to 1.0 parts by mass relative to 100 parts by mass of the aqueous medium, more preferably 0.001 to 0.5 parts by mass.

[0124] If the manufacturing of the specific polymer and the manufacturing of the fluoropolymer are not carried out sequentially, step 1 can be omitted. A commercially available specific polymer is prepared to replace step 1, and the specific polymer present in step 2 is preferably 0.0001 to 1.0 parts by mass relative to 100 parts by mass of the aqueous medium, more preferably 0.001 to 0.5 parts by mass.

[0125] Examples of commercially available polymers include Ardrich's poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate).

[0126] Commercially available polymers preferably have a D50 of 10–1000 nm, more preferably 10–300 nm, even more preferably 10–200 nm, and particularly preferably 10–150 nm.

[0127] Furthermore, the content of compound (1)-based units in commercially available polymers is preferably 50% by mass or more, more preferably 70% by mass or more, and more preferably 90% by mass or more, relative to all units of the polymer. As an upper limit, 100% by mass can be cited as an example.

[0128] Through the above steps, it is easy to obtain an aqueous dispersion of fluoropolymer containing particles with a D50 of 20-3000 nm of fluoropolymer having units based on specific fluorinated monomers and specific particles.

[0129] Furthermore, as mentioned earlier, it is hypothesized that during the polymerization of a specific fluorinated monomer, the monomer polymerizes within a specific particle. Therefore, the resulting fluorinated polymer particles may enter the specific particle, creating particles containing both the fluorinated polymer and the specific polymer. In particular, when the specific particle has a high affinity for the specific fluorinated monomer (e.g., when the specific particle is a particle of a specific polymer containing fluorine atoms), it is believed that particles with a D50 of 20–3000 nm containing both the fluorinated polymer and the specific polymer are readily generated.

[0130] The fluoropolymer aqueous dispersion of the present invention is an aqueous dispersion containing an aqueous medium, particles containing a fluoropolymer with a D50 of 20 to 3000 nm, and a specific polymer contained as particles in the aqueous medium or contained in the aforementioned particles containing the fluoropolymer.

[0131] Unless otherwise specified, particles containing fluoropolymers are also particles that may contain specific polymers.

[0132] The aqueous dispersion of the fluoropolymer contains, preferably, 1.0 to 50.0 parts by weight, more preferably 3 to 40 parts by weight, of the fluoropolymer-containing particles relative to 100 parts by weight of the aqueous medium.

[0133] The aqueous dispersion of the fluoropolymer preferably comprises 0.0001 to 1.0 parts by weight of the specific polymer relative to 100 parts by weight of the aqueous medium.

[0134] Furthermore, in the aqueous dispersion of the fluoropolymer, the content of the specific polymer is preferably 0.001 to 5.00 parts by mass relative to 100 parts by mass of particles containing the fluoropolymer, more preferably 0.005 to 3.00 parts by mass.

[0135] The particle size of the particles containing fluoropolymers is preferably 20–1000 nm.

[0136] The aqueous dispersion of the present invention containing particles of fluoropolymers does not require an emulsifier, and therefore can be easily converted into a dispersion of organic solvents such as N-methylpyrrolidone or acetone by solvent displacement.

[0137] A dispersion of an organic solvent can be formed by mixing an aqueous dispersion containing particles of a fluoropolymer with an organic solvent and then evaporating or dehydrating it with anhydrous sodium sulfate, etc.

[0138] The aqueous dispersion of fluoropolymers of the present invention can stably disperse fluoropolymers even without the presence of emulsifiers. Therefore, it is suitable for coating applications, adhesives, etc.

[0139] The polymer compositions of the present invention comprise the specific polymer and a fluoropolymer containing units based on the specific fluorinated monomer, exhibiting infrared absorption in the range of 1500–1800 cm⁻¹. -1 The peaks at this location originate from units based on compound (1). Particularly preferred are those at 1700–1800 cm⁻¹. -1 A composition having a peak at a certain point.

[0140] The peaks in the infrared spectrum described above are derived from units based on compound (1) present in a specific polymer, and may also be derived from units based on compound (1) which may also be included in fluoropolymers, as previously mentioned.

[0141] The polymer composition of the present invention can be readily obtained from the aqueous dispersion of the present invention obtained through the aforementioned step 2. That is, a powder of the polymer composition can be obtained by agglomerating the polymer from the aqueous dispersion of the present invention. Furthermore, the powdered polymer composition obtained by agglomeration can be homogenized by melt mixing or the like to produce a molded material containing a fluoropolymer and a specific polymer in the form of granules, particles, or the like, and the powdered polymer composition obtained by agglomeration can also be molded into a molded article by melt molding or the like.

[0142] Examples of coagulation methods include freeze coagulation, acid coagulation, alkali coagulation, and coagulation using coagulants, but these are not limited to.

[0143] In the case of freeze-coagulation, the coagulation temperature is preferably 0–5°C. The coagulation time is preferably 1 hour or more, more preferably 2 hours or more.

[0144] In the event of acid coagulation, the method of adding an acid-containing solution to the aqueous dispersion of the present invention is preferred. Examples of acids added include hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, and hydrofluoric acid, with hydrochloric acid being preferred. The concentration of the acid in the acid-containing solution is preferably 0.1–50% by mass, more preferably 1–30% by mass, and even more preferably 1–10% by mass.

[0145] As a method for alkali coagulation, it is preferable to add an alkaline solution to the aqueous dispersion of the present invention. Examples of alkaline substances to be added include sodium hydroxide, potassium hydroxide, and ammonium carbonate, with sodium hydroxide being preferred. The concentration of the alkaline solution is preferably 0.1–50% by mass, more preferably 1–30% by mass, and even more preferably 1–10% by mass.

[0146] For coagulation using a condensing agent, known condensing agents can be used. Examples of known condensing agents include ammonium salts, calcium salts, and magnesium salts. Specifically, examples include aluminum sulfate, and condensing agents with the general formula M'Al(SO4)2· 12 The alum, calcium nitrate, and magnesium sulfate represented by H2O (where M' is a monovalent cation other than lithium), with alum being preferred, and potassium alum with M being particularly preferred.

[0147] As a coagulation method, alkaline coagulation is preferred from the perspective of its particularly ease of execution. The rationale is not yet clear, but it is considered that the specific polymer is hydrolyzed under alkaline conditions, allowing for efficient coagulation of fluoropolymers.

[0148] The melting point of the fluoropolymer in the polymer composition of the present invention is preferably 150°C or higher, more preferably 150–330°C, even more preferably 180–320°C, further preferably 220–310°C, and even more preferably 260–300°C. If the melting point is within this range, the fluoropolymer exhibits high heat resistance and is therefore preferred.

[0149] Example

[0150] The present invention will now be described in detail with reference to embodiments and comparative examples, but the present invention is not limited thereto.

[0151] Additionally, in the following embodiments, the infrared absorption spectrum is in the range of 1700–1800 cm⁻¹ -1 Fluoropolymers with peaks in the range refer to fluoropolymers containing a specific polymer used in the manufacture of the fluoropolymer, i.e., the polymer composition containing the specific polymer and the fluoropolymer (wherein the presence of fluoropolymers containing units based on compound (1) is not excluded).

[0152] Even without measuring the infrared absorption spectrum, the fluoropolymer obtained in the examples is considered to be the polymer composition comprising the specific polymer and the fluoropolymer.

[0153] The various measurement and evaluation methods are described below.

[0154] D50 (nm) of polymer particles in aqueous dispersion:

[0155] Aqueous dispersions of polymer particles were used as samples, and particle size distribution was measured using a laser diffraction-scattering particle size analyzer (Otsuka Electronics Co., Ltd. ELSZ).

[0156] Confirmation of specific polymers:

[0157] pass 1 H-NMR analysis confirmed the presence of a specific polymer.

[0158] Q(mm 3 Determination of / s):

[0159] The Q value (also known as volumetric flow rate) was measured using a flow meter (manufactured by Shimadzu Corporation). For PFA, the measurement was performed at 380°C, and for ETFE and FEP, at 297°C, with loads of 7 kg, 30 kg, or 50 kg.

[0160] The proportions of each unit in the polymer:

[0161] The proportions of each unit in the polymer are determined by... 19 The results were obtained through F-NMR analysis, fluorine content analysis, and infrared absorption spectroscopy analysis.

[0162] Storage modulus G' of the polymer:

[0163] The polymer was measured using a rubber processing analyzer (RPA2000, Alpha Technologies) according to ASTM D5289 and ASTM D6204 conditions at a temperature of 100°C, an amplitude of 0.5 degrees, and a frequency of 50 times / minute. The measured value is the storage modulus G'. The storage modulus G' of a polymer is an indicator of the rubber properties of cross-linked rubber articles.

[0164] Melting point (°C):

[0165] The melting point is the temperature at which the heat of fusion occurs during melting, measured using a differential scanning calorimeter (NETZSCH DSC 3500Sirius) under a nitrogen atmosphere. The temperature change sequence during the measurement was -20℃→310℃→-70℃→310℃, with each heating rate of 10℃ / min and a cooling rate of 5℃ / min. The temperature at which the heat of fusion occurs during the second heating after cooling to -70℃ is taken as the melting point.

[0166] Thermogravimetric reduction temperatures (5% reduction point, 1% reduction point):

[0167] The temperature at which the weight decreases by 5% and 1% when heated at 10°C / minute in air using a differential thermogravimetric analysis (TG-DTA) device (NETZSCH STA2500Regulus).

[0168] [Preparation of aqueous dispersions of specific polymers]

[0169] (Refer to Example 1)

[0170] After purging a 1L glass polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG, and ultrapure water (740g), sodium sulfite (88mg), and n-butyl methacrylate (hereinafter referred to as "nBMA") (330mg) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and 3.8ml of a solution (5% by mass) dissolved in deionized water (hereinafter referred to as "KPS") was injected into the polymerization tank to polymerize nBMA. After 30 minutes, the mixture was drained from the polymerization tank to obtain an aqueous dispersion of polynBMA. The D50 of the polynBMA particles in the aqueous dispersion was 60nm.

[0171] The water was then removed under reduced pressure, and the product was vacuum dried at room temperature. The obtained polynBMA was dissolved in acetone-d6 and analyzed by NMR.

[0172] 1 H-NMR (acetone-d6): 1.0ppm (br, 3H), 1.1ppm (br, 2H), 1.3ppm (br, 1H), 1.9-2.4ppm (br, 6H), 4.2ppm (br, 2H)

[0173] (See Example 2 for reference)

[0174] Except that 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (hereinafter also referred to as "MHFBE") (624 mg) was used instead of nBMA (330 mg), the experiment was conducted in the same manner as in Reference Example 1. The D50 of the polyMHFBE particles in the aqueous dispersion was 131 nm.

[0175] 1 H-NMR (acetone-d6): 1.1ppm (br, 2H), 1.3ppm (br, 1H), 1.9-2.4ppm (br, 2H), 4.8ppm (br, 2H)

[0176] (Refer to Example 3)

[0177] After purging a 1L glass polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG, and ultrapure water (740g), sodium sulfite (88mg), nBMA (330mg), ferric(II) sulfate heptahydrate (11mg), and Chelest HC (17mg) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and 3.8ml of KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank to polymerize nBMA. After 30 minutes, the reaction solution was drained from the polymerization tank to obtain an aqueous dispersion of polynBMA. The D50 of the polynBMA particles in the aqueous dispersion was 86nm.

[0178] (Refer to Example 4)

[0179] Except that isobutyl methacrylate (330 mg) was used instead of nBMA (330 mg), the experiment was conducted in the same manner as in Reference Example 3. The D50 of the poly(isobutyl methacrylate) particles in the aqueous dispersion was 58.3 nm.

[0180] (Refer to Example 5)

[0181] Except that cyclohexyl methacrylate (390 mg) was used instead of nBMA (330 mg), the experiment was conducted in the same manner as in Reference Example 3. The D50 of the poly(cyclohexyl methacrylate) particles in the aqueous dispersion was 94.3 nm.

[0182] (Refer to Example 6)

[0183] Except that phenyl methacrylate (377 mg) was used instead of nBMA (330 mg), the experiment was conducted in the same manner as in Reference Example 3. The D50 of the poly(phenyl methacrylate) particles in the aqueous dispersion was 41.6 nm.

[0184] (Refer to Example 7)

[0185] Except that 2-methoxyethyl methacrylate (335 mg) was used instead of nBMA (330 mg), the experiment was conducted in the same manner as in Reference Example 3. The D50 of the poly(2-methoxyethyl methacrylate) particles in the aqueous dispersion was 103.7 nm.

[0186] (Refer to Example 8)

[0187] Except that MHFBE (624 mg) was used instead of nBMA (330 mg), the experiment was conducted in the same manner as in Reference Example 3. The D50 of the poly-MHFBE particles in the aqueous dispersion was 90.6 nm.

[0188] (Comparative Example 1)

[0189] After purging the 1.2L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG. Ultrapure water (630g), tert-butanol (72g), a CF3CF2OCF2CF2OCF2COONH4 aqueous solution (30% by mass, 12g), and a NaOH aqueous solution (2% by mass, 3.5g) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and the pressure was increased to 1.9 MPaG using a mixed monomer with a TFE / E ratio of 86 / 14. A KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank. After the pressure in the polymerization tank began to decrease, a mixed monomer with a TFE / E ratio of 54 / 46 was added to maintain the internal pressure in the polymerization tank at 1.9 MPaG, allowing the polymerization to continue. At the point when 50g of mixed monomer had been continuously added, the polymerization tank was cooled to room temperature, and the gas in the polymerization tank was vented to the atmosphere. The polymerization time was 210 minutes. The solids concentration of the resulting aqueous dispersion of the copolymer was approximately 7%. Furthermore, the D50 of the copolymer particles in the aqueous dispersion is 297 nm.

[0190] The aqueous dispersion was cooled to cause the copolymer particles to aggregate, thereby obtaining a powder. The copolymer powder was then dried at 150°C. The Q value of the obtained copolymer powder under a 50 kg load was 115 mm. 3 / s, the molar ratio of TFE units to E units in the copolymer is 54.7 / 45.3.

[0191] [Manufacturing of fluoropolymers]

[0192] (Example 1)

[0193] [Process 1]

[0194] After purging the 1L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG. Ultrapure water (1274g), sodium sulfite (152mg), nBMA (568mg), ferric(II) sulfate heptahydrate (19mg), and Chelest HC (29mg) were then added. The solution in the polymerization tank was stirred while the temperature was raised to 60°C. 6.5ml of a KPS solution (5% by mass) dissolved in deionized water was then injected into the polymerization tank to polymerize the nBMA. The amount of nBMA added indicates that 0.044 parts by mass of polynBMA are present in 100 parts by mass of the aqueous medium.

[0195] [Process 2]

[0196] Subsequently, the polymerization tank was pressurized to 2.6 MPaG using a mixed monomer with a TFE / E molar ratio of 86 / 14, and 19.5 mL of a KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank. After the pressure inside the polymerization tank began to decrease, a mixed monomer with a TFE / E molar ratio of 54 / 46 was added to maintain the internal pressure at 2.6 MPaG, allowing polymerization to continue. For every 5 g of mixed monomer injected, 2 mL of a sodium sulfite aqueous solution (1.8% by mass) was added to the polymerization tank. At the point when 140 g of mixed monomer had been continuously added, the polymerization tank was cooled to room temperature. The polymerization time was 377 minutes. The solids concentration of the resulting aqueous dispersion of the fluoropolymer was approximately 9%. Furthermore, the D50 of the fluoropolymer particles in the aqueous dispersion was 240 nm.

[0197] The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. The fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 50 kg load was 56 mm. 3 The molar ratio of TFE units to E units in the fluoropolymer is 54.7 / 45.3. The melting point of the obtained fluoropolymer is 270℃. Furthermore, for the obtained fluoropolymer, at 1740 cm⁻¹... -1 Peaks from the infrared absorption spectrum of a specific polymer were detected at the location.

[0198] N-methylpyrrolidone (hereinafter referred to as "NMP") (20 g) was added to the obtained aqueous dispersion (20 g) of the fluoropolymer to prepare a mixture. Then, water was removed under reduced pressure, and anhydrous magnesium sulfate was added. The anhydrous magnesium sulfate was removed by filtration to obtain an NMP dispersion of ETFE. The solids concentration was approximately 9%.

[0199] (Example 2)

[0200] [Process 1]

[0201] After purging the 1.2L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG, and ultrapure water (740g), sodium sulfite (88mg), and MHFBE (624mg) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and 3.8ml of KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank to polymerize MHFBE.

[0202] Based on the amount of MHFBE added, it can be seen that 0.084 parts by mass of poly(MHFBE) are present in 100 parts by mass of aqueous medium.

[0203] [Process 2]

[0204] Subsequently, the polymerization tank was pressurized to 1.9 MPaG using a mixed monomer with a TFE / E molar ratio of 86 / 14. 11.3 ml of KPS solution (5% by mass) dissolved in deionized water and 0.85 g of PFBE were then injected into the polymerization tank. After the pressure inside the polymerization tank began to decrease, a mixed monomer with a TFE / E molar ratio of 54 / 46 was added to maintain the internal pressure at 1.9 MPaG, allowing polymerization to continue. When the amount of mixed monomer added reached 40 g, 0.85 g of PFBE was added. At the point when 60 g of mixed monomer was continuously added, the polymerization tank was cooled to room temperature. The polymerization time was 690 minutes. The resulting aqueous dispersion of the fluoropolymer had a solids concentration of approximately 8%. Furthermore, the D50 of the fluoropolymer particles in the aqueous dispersion was 221 nm.

[0205] The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. The fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 50 kg load was 0.35 mm. 3 The molar ratio of TFE units / E units / PFBE units in the fluoropolymer is 54.2 / 45.1 / 0.67. The melting point of the obtained fluoropolymer is 265℃. For the obtained fluoropolymer, at 1760 cm⁻¹... -1 Peaks from the infrared absorption spectrum of a specific polymer were detected at the location.

[0206] (Example 3)

[0207] [Process 1]

[0208] After purging the 1L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG, and ultrapure water (1274g), sodium sulfite (152mg), nBMA (568mg), ferric(II) sulfate heptahydrate (19mg), and Chelest HC (29mg) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and 10ml of KPS solution (3.3% by mass) dissolved in deionized water was injected into the polymerization tank to polymerize nBMA.

[0209] Based on the amount of nBMA added, it can be seen that 0.044 parts by mass of polynBMA are present in 100 parts by mass of aqueous medium.

[0210] [Process 2]

[0211] After 30 minutes, the pressure was increased to 2.6 MPaG using a mixed monomer with a TFE / E ratio of 86 / 14. 40 mL of a KPS solution (3.3% by mass) dissolved in deionized water, along with PFBE (1.5 g) and an IAH aqueous solution (5% by mass, 2 mL), was then injected into the polymerization tank. Once the pressure in the polymerization tank began to decrease, a mixed monomer with a TFE / E ratio of 54 / 46 was added to maintain the internal pressure at 2.6 MPaG. For every 10 g of mixed monomer added, an IAH aqueous solution (5% by mass, 2 mL) was added to continue the polymerization. At the point when 50 g of mixed monomer had been continuously added, the polymerization tank was cooled to room temperature. The polymerization time was 450 minutes. The solids concentration of the resulting aqueous dispersion of the fluoropolymer was approximately 4%. Furthermore, the D50 of the fluoropolymer particles in the aqueous dispersion was 135 nm.

[0212] The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. The fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 50 kg load was 13 mm. 3 / s, the molar ratio of TFE units / E units / PFBE units / IAH units in the copolymer is 54.1 / 45.6 / 0.3 / 0.2.

[0213] (Example 4)

[0214] [Process 1]

[0215] After purging the 1.2L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG, and ultrapure water (740g), sodium sulfite (88mg), and MHFBE (624mg) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and 3.8ml of KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank to polymerize MHFBE.

[0216] Based on the amount of MHFBE added, it can be seen that 0.084 parts by mass of poly(MHFBE) are present in 100 parts by mass of aqueous medium.

[0217] [Process 2]

[0218] After 30 minutes, the polymerization tank was pressurized to 1.9 MPaG using a mixed monomer with a TFE / E ratio of 86 / 14. 15.1 ml of a KPS solution (5% by mass) dissolved in deionized water, along with PFBE (1.1 g) and methanol (1.5 g), was then injected into the polymerization tank. Once the pressure inside the tank began to decrease, a mixed monomer with a TFE / E ratio of 54 / 46 was added to maintain the internal pressure at 1.9 MPaG, allowing polymerization to continue. At the point when 30 g of the mixed monomer had been continuously added, the polymerization tank was cooled to room temperature. The polymerization time was 407 minutes. The resulting aqueous dispersion of the fluoropolymer had a solids concentration of approximately 4%. Furthermore, the D50 of the fluoropolymer particles in the aqueous dispersion was 141 nm.

[0219] The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. The fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 50 kg load was 130 mm. 3 / s, the molar ratio of TFE units / E units / PFBE units in the fluoropolymer is 54.0 / 45.0 / 1.0.

[0220] (Example 5)

[0221] [Process 1]

[0222] After purging the 1.2L stainless steel polymerization tank with nitrogen, the pressure was reduced, and ultrapure water (740g), sodium sulfite (88mg), nBMA (330mg), ferric(II) sulfate heptahydrate (11mg), and Chelest HC (17mg) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and 3.8ml of KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank to polymerize nBMA.

[0223] Based on the amount of nBMA added, it can be seen that 0.044 parts by mass of polynBMA are present in 100 parts by mass of aqueous medium.

[0224] [Process 2]

[0225] After 30 minutes, the pressure was increased to 1.4 MPaG using TFE, and 25 mL of KPS solution (5% by mass) dissolved in deionized water and 23.5 g of PPVE were injected into the polymerization tank. Once the pressure inside the polymerization tank began to decrease, TFE was added to maintain the internal pressure at 1.4 MPaG, allowing polymerization to continue. For every 3 g of mixed monomers injected, 1.9 mL of sodium sulfite aqueous solution (1.2% by mass) was added to the polymerization tank. At the point when 30 g of TFE was continuously added, the polymerization tank was cooled to room temperature. The polymerization time was 197 minutes. The solids concentration of the resulting aqueous dispersion of the fluoropolymer was approximately 4%. Furthermore, the D50 of the fluoropolymer particles in the aqueous dispersion was 131 nm.

[0226] The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. The fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 50 kg load was 680 mm. 3 / s, the molar ratio of TFE units to PPVE units in the fluoropolymer is 98.6 / 1.4.

[0227] (Example 6)

[0228] [Process 1]

[0229] After degassing a 2100mL stainless steel pressure reactor equipped with anchor fins, 1000g of ultrapure water, 119mg of sodium sulfite, 297mg of nBMA, and 15mg of ferric(II) sulfate heptahydrate were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 70°C, and 5ml of KPS solution (5% by mass) dissolved in ultrapure water was injected into the polymerization tank to polymerize the nBMA.

[0230] Based on the amount of nBMA added, it can be seen that 0.030 parts by mass of polynBMA are present in 100 parts by mass of aqueous medium.

[0231] [Process 2]

[0232] After 30 minutes, 82g of PMVE and 17g of TFE (TFE:PMVE = 25:75 molar ratio) were added. The temperature was increased, and the reactor internal pressure reached 1.14 MPaG when the internal temperature reached 80°C. 40mL of ammonium persulfate solution (5% by mass) dissolved in ultrapure water was added to initiate polymerization. Immediately thereafter, 0.7g of 1,4-diiodoperfluorobutane was added along with 10g of ultrapure water. As polymerization proceeded, TFE was injected at the point where the reactor internal pressure dropped to 1.13 MPaG, raising the reactor internal pressure back to 1.14 MPaG. This process was repeated, with 7g of PMVE injected for every 8g of TFE injected.

[0233] At the point when the total added mass of TFE reached 80g, the addition of monomers added after the start of polymerization (hereinafter referred to as "post-added monomers") was stopped, and the reactor temperature was cooled to 10°C to stop the polymerization reaction, obtaining a latex containing a fluoropolymer (hereinafter referred to as "fluoropolymer"). The polymerization time was 300 minutes. Furthermore, the total added mass of the post-added monomers was 80g TFE and 63g PMVE, with a molar ratio of TFE:PMVE = 65:35. The solids concentration of the resulting aqueous dispersion of the copolymer was approximately 13%. The latex was added to a 5% (w / w) aqueous solution of potassium aluminum sulfate to coagulate and separate the fluoropolymer. The fluoropolymer was filtered out, washed with demineralized water, and vacuum dried at 50°C to obtain a white fluoropolymer. The molar ratio of the monomers in the fluoropolymer was TFE:PMVE = 63.3:36.7, and the iodine content was 0.15% (w / w). In addition, the storage modulus G' of the fluorinated elastic copolymer is 112 kPa.

[0234] (Example 7)

[0235] Except that isobutyl methacrylate (568 mg) was used instead of nBMA (568 mg), the experiment was conducted in the same manner as in Example 6. The polymerization time was 375 minutes. The solids concentration of the resulting aqueous dispersion of the copolymer was approximately 13%.

[0236] Latex was added to a 5% (w / w) aqueous solution of potassium aluminum sulfate to cause the fluorinated elastic copolymer to coagulate and separate. The fluorinated elastic copolymer was filtered out, washed with demineralized water, and vacuum dried at 50°C to obtain a white fluorinated elastic copolymer. The molar ratio of the monomers in the fluorinated elastic copolymer was TFE:PMVE = 64.7:35.3, and the iodine content was 0.15% (w / w). Furthermore, the storage modulus G' of the fluorinated elastic copolymer was 152 kPa.

[0237] (Example 8)

[0238] [Process 1]

[0239] After degassing a 2100mL stainless steel pressure reactor equipped with anchor wings, 1000g of ultrapure water, 119mg of sodium sulfite, 297mg of nBMA, and 15mg of ferric(II) sulfate heptahydrate were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 70°C, and 5mL of a 5% by mass ultrapure aqueous solution of KPS was injected into the polymerization tank to polymerize the nBMA.

[0240] Based on the amount of nBMA added, it can be seen that 0.030 parts by mass of polynBMA are present in 100 parts by mass of aqueous medium.

[0241] [Process 2]

[0242] After 30 minutes, 0.4 g of 8CNVE (CF2 = CFOCF2CF(CF3)OCF2CF2CN) was added together with 10 g of ultrapure water. Then, 63 g of PMVE and 13 g of TFE (TFE:PMVE = 24:74 molar ratio) were added. The temperature was increased, and the reactor internal pressure reached 0.93 MPaG when the internal temperature reached 80°C. 40 mL of a 5% (w / w) ultrapure water solution of ammonium persulfate was added to initiate polymerization. As polymerization proceeded, TFE was added at the point where the reactor internal pressure decreased to 0.92 MPaG, raising the reactor internal pressure to 0.93 MPaG. This process was repeated, adding 7 g of PMVE and 0.4 g of 8CNVE for every 6 g of TFE added. When the total added TFE reached 80 g, the polymerization was stopped, and monomers were added to cool the reactor internal temperature to 10°C, thus stopping the polymerization reaction and obtaining a latex containing a fluorinated elastic copolymer. The polymerization time was 300 minutes. Furthermore, the total added mass of the post-added monomers was 80 g TFE, 50 g PMVE, and 4.3 g 8CNVE, which translates to a molar ratio of TFE:PMVE:8CNVE = 72:27:1. The resulting aqueous dispersion of the copolymer had a solids content of approximately 14%.

[0243] Latex was added to a 5% (w / w) aqueous solution of potassium aluminum sulfate to cause the fluorinated elastic copolymer to coagulate and separate. The fluorinated elastic copolymer was filtered out, washed with demineralized water, and vacuum dried at 50°C to obtain a white fluorinated elastic copolymer. The molar ratio of the monomers in the fluorinated elastic copolymer was TFE:PMVE:8CNVE = 69.1:30.3:0.6. Furthermore, the storage modulus G' of the fluorinated elastic copolymer was 359 kPa.

[0244] (Example 9)

[0245] After purging the 1.3L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1MPaG, and ultrapure water (640g), tert-butanol (11g), and poly(MHFBE) (50mg) (trade name of Aldrich: poly(2,2,3,3,4,4,4-heptafluorobutyl methacrylate)) were added. The solution in the polymerization tank was stirred while the temperature was raised to 60°C.

[0246] Next, 16g of HFP was added, and the polymerization tank was pressurized to 1.6 MPaG using TFE monomer. 20ml of APS solution (5% by mass) dissolved in deionized water was then injected into the polymerization tank. After the pressure inside the polymerization tank began to decrease, TFE monomer was added to maintain the internal pressure at 1.6 MPaG, allowing polymerization to continue. At the point when 83g of TFE monomer had been continuously added, the polymerization tank was cooled to room temperature. The resulting aqueous dispersion of the fluoropolymer had a solids concentration of approximately 7%. The aqueous dispersion was cooled to allow the fluoropolymer particles to agglomerate, thus obtaining a powder. This fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 7kg load was 23 mm. 3 / s. The molar ratio of TFE units to HFP units in the fluoropolymer is 98.6 / 1.4.

[0247] (Example 10)

[0248] After purging the 1.2L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG, and ultrapure water (740g), sodium sulfite (88mg), poly(MHFBE) (30mg), and tert-butanol (11g) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C. The polymerization tank was pressurized to 2.6 MPaG using a mixed monomer with a TFE / E ratio of 86 / 14, and 19.5ml of KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank. After the pressure in the polymerization tank began to decrease, a mixed monomer with a TFE / E ratio of 54 / 46 was added to maintain the internal pressure in the polymerization tank at 2.6 MPaG, allowing the polymerization to continue. At the point when 30g of mixed monomer had been continuously added, the polymerization tank was cooled to room temperature. The polymerization time was 110 minutes. The solids concentration of the resulting aqueous dispersion of the fluoropolymer was approximately 4%. Furthermore, the D50 of the fluoropolymer particles in the aqueous dispersion was 250 nm. The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. This fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 30 kg load was 5.5 mm. 3 / s, the molar ratio of TFE units to E units in the fluoropolymer is 54.7 / 45.3. The melting point of the obtained fluoropolymer is 272℃. For the obtained fluoropolymer, at 1760cm -1 Peaks from the infrared absorption spectrum of a specific polymer were detected at the location.

[0249] (Example 11)

[0250] After purging the 1.2L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG, and ultrapure water (740g), sodium sulfite (88mg), and MHFBE (624mg) were added. Then, while stirring the solution in the polymerization tank, the temperature was raised to 60°C, and 4ml of KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank to polymerize MHFBE.

[0251] Based on the amount of MHFBE added, it can be seen that 0.084 parts by mass of poly(MHFBE) are present in 100 parts by mass of aqueous medium.

[0252] Subsequently, the polymerization tank was pressurized to 2.6 MPaG using a mixed monomer with a TFE / E molar ratio of 86 / 14. 12 ml of a KPS solution (5% by mass) dissolved in deionized water, along with 11 g of tert-butanol and 2.2 g of MeOH, was injected into the polymerization tank. After the pressure inside the polymerization tank began to decrease, a mixed monomer with a TFE / E molar ratio of 54 / 46 was added to maintain the internal pressure at 2.6 MPaG, allowing polymerization to continue. When the amount of mixed monomer added reached 10 g, 0.7 g of PFBE was added. Thereafter, 0.7 g of PFBE was added every 14 g of mixed monomer. At the point when 80 g of mixed monomer was continuously added, the polymerization tank was cooled to room temperature. The polymerization time was 458 minutes. The solids concentration of the resulting aqueous dispersion of the fluoropolymer was approximately 9%. Furthermore, the D50 of the fluoropolymer particles in the aqueous dispersion was 262 nm.

[0253] The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. The fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 7 kg load was 5 mm. 3 The molar ratio of TFE units / E units / PFBE units in the fluoropolymer is 53.8 / 45.3 / 0.96. The melting point of the obtained fluoropolymer is 262℃. For the obtained fluoropolymer, at 1760 cm⁻¹... -1 Peaks originating from the infrared absorption spectrum of a specific polymer were detected. The 1% thermogravimetric decrease temperature determined by TG-DTA was 429℃, and the 5% thermogravimetric decrease temperature was 455℃.

[0254] (Example 12)

[0255] [Process 1]

[0256] After purging the 1L stainless steel polymerization tank with nitrogen, the pressure was reduced to -0.1 MPaG. Ultrapure water (1274g), sodium sulfite (152mg), nBMA (568mg), ferric(II) sulfate heptahydrate (19mg), and Chelest HC (29mg) were then added. The solution in the polymerization tank was stirred while the temperature was raised to 60°C. 6.5ml of a KPS solution (5% by mass) dissolved in deionized water was then injected into the polymerization tank to polymerize the nBMA. The amount of nBMA added indicates that 0.044 parts by mass of polynBMA are present in 100 parts by mass of the aqueous medium.

[0257] [Process 2]

[0258] Subsequently, the polymerization tank was pressurized to 2.5 MPaG using vinylidene fluoride (hereinafter also referred to as "VDF"), and 19.5 ml of KPS solution (5% by mass) dissolved in deionized water was injected into the polymerization tank. After the pressure inside the polymerization tank began to decrease, VDF was added to maintain the internal pressure of the polymerization tank at 2.5 MPaG, allowing the polymerization to continue. At the point when 30 g of VDF was continuously added, the polymerization tank was cooled to room temperature, and the gas inside the polymerization tank was vented to the atmosphere. The polymerization time was 120 minutes. The solids concentration of the resulting aqueous dispersion of the fluoropolymer was approximately 4%.

[0259] The aqueous dispersion was cooled to cause the fluoropolymer particles to agglomerate, thus obtaining a powder. The fluoropolymer powder was then dried at 150°C. The Q value of the obtained fluoropolymer powder under a 30 kg load was 1 mm. 3 The resulting fluoropolymer has a melting point of 172°C at 1740 cm⁻¹. -1 Peaks from the infrared absorption spectrum of a specific polymer were detected at the location.

[0260] The manufacturing methods for each embodiment are summarized in Table 1, and the aqueous dispersions of fluoropolymers are summarized in Table 2.

[0261] In addition, in Table 1, “polymerization initiation dose” refers to the amount of water-soluble polymerization initiator used in step 1 relative to 1 mole of compound (1) (molar amount), and “specific polymer amount” refers to the content of specific polymer in 100 parts by mass of the aqueous medium used in step 2 (parts by mass).

[0262] In addition, in Table 2, "Fluoropolymer content" refers to the content of fluoropolymer in the obtained aqueous dispersion relative to 100 parts by mass of water (parts by mass), "Specific polymer content A" refers to the content of specific polymer in the obtained aqueous dispersion relative to 100 parts by mass of water (parts by mass), and "Specific polymer content B" refers to the content of specific polymer in the obtained aqueous dispersion relative to 100 parts by mass of fluoropolymer (parts by mass).

[0263] [Table 1]

[0264] Example sequence number 1 2 3 4 5 6 7 8 9 10 11 12 Fluoropolymers ETFE ETFE ETFE ETFE PFA PF2 PF2 PF2 FEP ETFE ETFE PVdF Polymerization initiation dose 0.6 0.6 0.6 0.3 0.6 0.9 0.5 0.9 1.3 0.6 Specific polymer amount 0.044 0.084 0.044 0.084 0.044 0.030 0.057 0.030 0.008 0.004 0.084 0.045

[0265] [Table 2]

[0266] Example sequence number 1 2 3 4 5 6 7 8 9 10 11 12 Fluoropolymers ETFE ETFE ETFE ETFE PFA PF2 PF2 PF2 FEP ETFE ETFE PVdF Fluoropolymer content 9 8 4 4 4 13 14 7 4 9 4 Specific polymer amount A 0.044 0.084 0.044 0.084 0.044 0.030 0.057 0.030 0.008 0.004 0.084 0.045 Specific polymer amount B 0.495 1.054 1.115 2.108 1.115 0.228 0.212 O.112 0.101 0.937 1.115

[0267] In addition, the entire contents of the specification, claims and abstract of Japanese Patent Application No. 2019-060003, filed on March 27, 2019, are incorporated herein by reference as disclosure of this invention.

Claims

1. A method for manufacturing a fluoropolymer, comprising, in an aqueous medium, without the use of an emulsifier, polymerizing at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene, and vinylidene fluoride in the presence of a first polymer containing units based on a compound represented by formula (1), wherein, The first polymer present in an aqueous medium consists of 50% by volumetric accumulation of particles with diameters of 10–1000 nm. CXY=CR 1 -L-R 2 ···(1) Where X and Y represent hydrogen atoms, and R... 1 It indicates an alkyl group having 1 to 3 carbon atoms, where L represents -CO-O-* or -O-CO-*, and * indicates that it is related to R. 2 The bonding position, R 2 It represents cyclohexyl, phenyl, and alkyl groups having 1 to 4 carbon atoms.

2. The manufacturing method as described in claim 1, wherein, The amount of the first polymer present is 0.0001 to 1.0 parts by mass relative to 100 parts by mass of the aqueous medium.

3. The manufacturing method as described in claim 1 or 2, wherein, The first polymer is a polymer obtained by polymerizing the compound represented by formula (1) with 0.1 to 5.0 moles of a water-soluble polymerization initiator relative to 1 mole of the compound represented by formula (1).

4. A method for manufacturing a fluoropolymer, without using an emulsifier, wherein a compound represented by formula (1) is polymerized in an aqueous medium to obtain an aqueous medium containing a first polymer composed of particles with a diameter of 10 to 1000 nm, comprising 50% by volume. A fluoropolymer is produced by polymerizing the compound represented by formula (1) using 0.1 to 5.0 moles of a water-soluble polymerization initiator relative to 1 mole of the compound represented by formula (1), and then polymerizing at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene, and vinylidene fluoride in the aqueous medium containing the first polymer: CXY=CR 1 -L-R 2 ···(1) Where X and Y represent hydrogen atoms, and R... 1 It indicates an alkyl group having 1 to 3 carbon atoms, where L represents -CO-O-* or -O-CO-*, and * indicates that it is related to R. 2 The bonding position, R 2 It represents cyclohexyl, phenyl, and alkyl groups having 1 to 4 carbon atoms.

5. The manufacturing method as described in claim 4, wherein, The aqueous medium containing the first polymer is an aqueous medium used to manufacture the first polymer so that the first polymer is present.

6. The manufacturing method as described in claim 4 or 5, wherein, During the polymerization of the fluorinated monomer, the amount of the first polymer present is 0.0001 to 1.0 parts by mass relative to 100 parts by mass of the aqueous medium.

7. An aqueous dispersion of a fluoropolymer, which does not contain an emulsifier, comprises: Aqueous media; The fluoropolymer contains a volume-based cumulative 50% of particles with a diameter of 20–3000 nm, wherein the fluoropolymer contains units based on at least one fluorinated monomer selected from tetrafluoroethylene, trifluorochloroethylene, and vinylidene fluoride; and A first polymer comprising 50% by volume of particles with diameters of 10–1000 nm, containing units of compounds represented by the following formula (1): CXY=CR 1 -L-R 2 ···(1) Where X and Y represent hydrogen atoms, and R... 1 It represents an alkyl group having 1 to 3 carbon atoms, where L represents -CO-O-* or -O-CO-*, and so on. * indicates that it is related to R 2 The bonding position, R 2 It represents cyclohexyl, phenyl, and alkyl groups having 1 to 4 carbon atoms.

8. The aqueous dispersion of the fluoropolymer as described in claim 7, wherein 100 parts by weight of the aqueous medium contains 1.0 to 50.0 parts by weight of particles containing the fluoropolymer.

9. The aqueous dispersion of the fluoropolymer as described in claim 7 or 8, wherein 100 parts by mass of the aqueous medium contains 0.0001 to 1.0 parts by mass of particles of the first polymer.