Coating composition, coating film, laminate and coated article

Abstract

Provided is a coating composition which comprises a fluororesin, a polymer (I) including a polymer unit (I) based on a monomer represented by general formula (I), and an aqueous medium, wherein the content of the polymer (I) is up to 2,000 mass ppm of the coating composition.　General formula (I): CX1X3=CX2R(-CZ1Z2-A0)m (In the formula, X1 and X3 are each independently F, Cl, H, or CF3, X2 represents H, F, an alkyl group, or a fluoroalkyl group, A0 is an anionic group, R is a linking group, Z1 and Z2 are each independently H, F, an alkyl group, or a fluoroalkyl group, and m is an integer of 1 or larger.)

Description

[Technical Field]

[0001] The present disclosure relates to coating compositions, coatings, laminates and coated articles. [Background technology]

[0002] Polytetrafluoroethylene (PTFE) has excellent heat resistance, chemical resistance, water and oil repellency, mold releasability, sliding properties, etc. For these reasons, aqueous dispersions containing PTFE are used as mold release agents for molding dies, rolls for office automation (OA) equipment, household products such as irons, kitchen appliances such as frying pans and hot plates, and as coating compositions in the fields of the food industry, electrical industry, and machinery industry.

[0003] Patent Document 1 describes an aqueous dispersion composition for a primer for a fluororesin coating layer, which contains (A) a water-soluble and curable polyamideimide-based and / or polyimide-based binder polymer, (B) ceramic spherical particles, (C) modified polytetrafluoroethylene particles, and (D) an aqueous medium, in which the modified polytetrafluoroethylene particles (C) have a melt creep viscosity of 8×10 at 380°C. 9 That's 1.0 x 10 10 The document describes an aqueous dispersion composition for a primer, characterized by modified polytetrafluoroethylene particles having a viscosity in the range of Pa·s or less and a standard specific gravity of 2.146 or more and 2.170 or less.

[0004] Patent Document 2 describes a laminate comprising a substrate, a primer layer formed on the substrate, the primer layer containing inorganic particles (a) having an average particle size of 3 μm or more and a heat-resistant resin (a) but not containing a fluororesin, an intermediate layer formed on the primer layer, the intermediate layer containing a fluororesin (b) and a heat-resistant resin (b), and a topcoat layer formed on the intermediate layer, the topcoat layer containing a fluororesin (c).

[0005] Patent Document 3 describes a method for producing a fluoropolymer, which includes a step of obtaining a fluoropolymer by polymerizing a fluoromonomer in an aqueous medium in the presence of a polymer (1) containing polymerized units (1) based on a monomer represented by the following general formula (1): CX2=CY(-CZ2-O-Rf-A) (1) (In the formula, X's are the same or different and are -H or -F; Y's are -H, -F, an alkyl group or a fluorine-containing alkyl group; Z's are the same or different and are -H, -F, an alkyl group or a fluoroalkyl group; Rf's are fluorine-containing alkylene groups having 1 to 40 carbon atoms or fluorine-containing alkylene groups having 2 to 100 carbon atoms and an ether bond; A's are -COOM, -SO3M or -OSO3M (M's are -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group, provided that at least one of X, Y, and Z contains a fluorine atom.

[0006] Patent Document 4 describes a method for producing an aqueous fluoropolymer dispersion, which comprises a step A of carrying out ultrafiltration, microfiltration, or dialysis membrane treatment, or a combination thereof, on a pre-treatment aqueous dispersion containing a fluoropolymer (excluding the polymer (I)) obtained by polymerization in the presence of a polymer (I) containing polymerization units (I) based on a monomer represented by the following general formula (I): CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 4853081 Specification [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-127142 [Patent Document 3] International Publication No. 2019 / 168183 [Patent Document 4] International Publication No. 2020 / 218620 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present disclosure is to provide a novel coating composition. [Means for solving the problem]

[0009] According to the present disclosure, there is provided a coating composition (sometimes referred to as a "first coating composition" in the present disclosure) containing a fluororesin, a polymer (I) containing polymerization units (I) based on a monomer represented by general formula (I), and an aqueous medium, wherein the content of the polymer (I) in the coating composition is 2000 mass ppm or less. CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater.

[0010] The viscosity of the first coating composition of the present disclosure is preferably 100 mPa·s or more and 1000 mPa·s or less. In the first coating composition of the present disclosure, the content of the fluororesin is preferably 15.0 mass % or more and 52.0 mass % or less relative to the coating composition. In the first coating composition of the present disclosure, the fluororesin is preferably at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, ethylene / tetrafluoroethylene copolymer, and ethylene / chlorotrifluoroethylene copolymer. The first coating composition of the present disclosure preferably has a stability retention time of 10 minutes or longer as measured by a stirring test. In the first coating composition of the present disclosure, the content of polymer (I) is preferably 0.1 ppm by mass or more relative to the coating composition. The first coating composition of the present disclosure preferably further contains a nonionic surfactant.

[0011] The present disclosure also provides a coating composition containing a fluororesin and an aqueous medium, which has a stability retention time of 10 minutes or more as measured by a stirring test and a viscosity of 50 mPa·s or more and 1000 mPa·s or less (sometimes referred to as a "second coating composition" in the present disclosure).

[0012] In the second coating composition of the present disclosure, the content of the fluororesin is preferably 15.0 mass % or more and 52.0 mass % or less relative to the coating composition. In the second coating composition of the present disclosure, it is preferable that the fluororesin contains at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, and tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer. In the second coating composition of the present disclosure, the fluororesin preferably contains at least polytetrafluoroethylene. In the second coating composition of the present disclosure, the content of polytetrafluoroethylene in the coating composition is preferably 60% by mass or more relative to the fluororesin. In the second coating composition of the present disclosure, it is preferable that the fluororesin contains only a tetrafluoroethylene / hexafluoropropylene copolymer, and that the content of the fluororesin is 30.0 mass% or more and 50.0 mass% or less relative to the coating composition. In the second coating composition of the present disclosure, it is preferred that the fluororesin contains only a tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, and that the content of the fluororesin is 30.0 mass% or more and 50.0 mass% or less relative to the coating composition.

[0013] The present disclosure also provides a coating composition (sometimes referred to as a "third coating composition" in the present disclosure) that contains a fluororesin, a nonionic surfactant, an anionic hydrocarbon surfactant, and an aqueous medium, and is substantially free of a fluorine-containing compound that has a hydrophilic group.

[0014] In the third coating composition of the present disclosure, the fluorine-containing compound having a hydrophilic group is preferably an anionic fluorine-containing surfactant containing fluorine in the anionic moiety having a molecular weight of 800 or less. In the third coating composition of the present disclosure, the content of the fluorine-containing compound having a hydrophilic group is preferably 100 ppb by mass or less. In the third coating composition of the present disclosure, the fluorine-containing compound having a hydrophilic group is H(CF2)7COOM, F(CF2)7COOM, F(CF2)5COOM, H(CF2)6COOM, CF3O(CF2)3OCHFCF2COOM, C3F7OCF(CF3)CF2OCF(CF3)COOM, CF3CF2CF2OCF(CF3)COOM, CF3CF2OCF2CF2OCF2COOM, C2F5OCF(CF3)CF2OCF(CF3)COOM, CF3OCF(CF3)CF2OCF(CF3)COOM, CF2ClCF2CF2OCF(CF3)CF2OCF2COOM, CF2ClCF2CF2OCF2CF(CF3)OCF2COOM, CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM, CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM, and [ka] (In each formula, M is H, metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group. In the third coating composition of the present disclosure, the content of the fluororesin is preferably 15.0 mass % or more and 52.0 mass % or less relative to the coating composition. In the third coating composition of the present disclosure, it is preferable that the fluororesin contains at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, and tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer. In the third coating composition of the present disclosure, the fluororesin preferably contains at least polytetrafluoroethylene. In the third coating composition of the present disclosure, the content of polytetrafluoroethylene in the coating composition is preferably 60 mass % or more relative to the fluororesin.

[0015] The coating composition of the present disclosure (in this disclosure, the first coating composition, second coating composition, and third coating composition of the present disclosure may be referred to as the "coating composition of the present disclosure") preferably further contains a film-forming agent. The coating composition of the present disclosure preferably further contains a binder resin, and the binder resin is at least one selected from the group consisting of polyamideimide, polyimide, polyethersulfone, and polyphenylene sulfide.

[0016] The present disclosure also provides a coating film obtained by applying the coating composition. The present disclosure also provides a laminate including the coating film. The present disclosure also provides a coated article comprising the coating film or the laminate. [Effects of the Invention]

[0017] According to the present disclosure, a new coating composition can be provided. [Brief explanation of the drawings]

[0018] [Figure 1] Figure 1(a) is a front view of the impeller used in the stirring test, and Figure 1(b) is a left side view of the impeller used in the stirring test. DETAILED DESCRIPTION OF THE INVENTION

[0019] Specific embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments.

[0020] In this disclosure, "organic group" means a group containing one or more carbon atoms or a group formed by removing one hydrogen atom from an organic compound. Examples of the "organic group" are: an alkyl group optionally having one or more substituents; an alkenyl group optionally having one or more substituents; an alkynyl group optionally having one or more substituents; a cycloalkyl group optionally having one or more substituents; a cycloalkenyl group optionally having one or more substituents, a cycloalkadienyl group optionally having one or more substituents, an aryl group optionally having one or more substituents; an aralkyl group optionally having one or more substituents; a non-aromatic heterocyclic group optionally having one or more substituents, a heteroaryl group optionally having one or more substituents, cyano group, formyl group, RaO-, RaCO-, RaSO2-, RaCOO-, RaNRaCO-, RaCONRa-, RaOCO-, RaOSO2-, and RaNRbSO2- (In these formulas, Ra independently represents: an alkyl group optionally having one or more substituents; an alkenyl group optionally having one or more substituents; an alkynyl group optionally having one or more substituents; a cycloalkyl group optionally having one or more substituents; a cycloalkenyl group optionally having one or more substituents, a cycloalkadienyl group optionally having one or more substituents, an aryl group optionally having one or more substituents; an aralkyl group optionally having one or more substituents; a non-aromatic heterocyclic group optionally having one or more substituents, or a heteroaryl group optionally having one or more substituents, Rb is independently H or an alkyl group which may have one or more substituents. Includes. The organic group is preferably an alkyl group which may have one or more substituents.

[0021] In the present disclosure, the term "substituent" refers to a substitutable group. Examples of the "substituent" include an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an acyloxy group, an acylamino group, an aliphatic oxy group, an aromatic oxy group, a heterocyclic oxy group, an aliphatic oxycarbonyl group, an aromatic oxycarbonyl group, a heterocyclic oxycarbonyl group, a carbamoyl group, an aliphatic sulfonyl group, an aromatic sulfonyl group, a heterocyclic sulfonyl group, an aliphatic sulfonyloxy group, an aromatic sulfonyloxy group, a heterocyclic sulfonyloxy group, a sulfamoyl group, an aliphatic sulfonamido group, an aromatic sulfonamido group, a heterocyclic sulfonamido group, an amino group, and an aliphatic amino group. groups, aromatic amino groups, heterocyclic amino groups, aliphatic oxycarbonylamino groups, aromatic oxycarbonylamino groups, heterocyclic oxycarbonylamino groups, aliphatic sulfinyl groups, aromatic sulfinyl groups, aliphatic thio groups, aromatic thio groups, hydroxy groups, cyano groups, sulfo groups, carboxy groups, aliphatic oxyamino groups, aromatic oxyamino groups, carbamoylamino groups, sulfamoylamino groups, halogen atoms, sulfamoylcarbamoyl groups, carbamoylsulfamoyl groups, dialiphatic oxyphosphinyl groups, and diaromatic oxyphosphinyl groups.

[0022] The aliphatic group may be saturated or unsaturated, and may have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic group include alkyl groups having a total of 1 to 8, preferably 1 to 4, carbon atoms, such as a methyl group, an ethyl group, a vinyl group, a cyclohexyl group, and a carbamoylmethyl group.

[0023] The aromatic group may have, for example, a nitro group, a halogen atom, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aromatic group include aryl groups having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms in total, such as a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group, and a 4-methanesulfonylphenyl group.

[0024] The heterocyclic group may have a halogen atom, a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the heterocyclic group include 5- or 6-membered heterocycles having a total of 2 to 12, preferably 2 to 10, carbon atoms, such as a 2-tetrahydrofuryl group and a 2-pyrimidyl group.

[0025] The acyl group may have an aliphatic carbonyl group, an arylcarbonyl group, a heterocyclic carbonyl group, a hydroxy group, a halogen atom, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the acyl group include acyl groups having a total of 2 to 8, preferably 2 to 4, carbon atoms, such as an acetyl group, a propanoyl group, a benzoyl group, and a 3-pyridinecarbonyl group.

[0026] The acylamino group may have an aliphatic group, an aromatic group, a heterocyclic group, etc., such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the acylamino group include acylamino groups having a total of 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms, and alkylcarbonylamino groups having a total of 2 to 8 carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc.

[0027] The aliphatic oxycarbonyl group may be saturated or unsaturated, and may have a hydroxy group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic oxycarbonyl group include alkoxycarbonyl groups having a total of 2 to 8, preferably 2 to 4, carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, and a (t)-butoxycarbonyl group.

[0028] The carbamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the carbamoyl group include an unsubstituted carbamoyl group, an alkylcarbamoyl group having a total of 2 to 9 carbon atoms, preferably an unsubstituted carbamoyl group, or an alkylcarbamoyl group having a total of 2 to 5 carbon atoms, such as an N-methylcarbamoyl group, an N,N-dimethylcarbamoyl group, or an N-phenylcarbamoyl group.

[0029] The aliphatic sulfonyl group may be saturated or unsaturated and may have a hydroxy group, an aromatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aliphatic sulfonyl group include alkylsulfonyl groups having a total of 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, such as a methanesulfonyl group.

[0030] The aromatic sulfonyl group may have a hydroxy group, an aliphatic group, an aliphatic oxy group, a carbamoyl group, an aliphatic oxycarbonyl group, an aliphatic thio group, an amino group, an aliphatic amino group, an acylamino group, a carbamoylamino group, etc. Examples of the aromatic sulfonyl group include arylsulfonyl groups having a total of 6 to 10 carbon atoms, such as a benzenesulfonyl group.

[0031] The amino group may have an aliphatic group, an aromatic group, a heterocyclic group, or the like.

[0032] The acylamino group may have, for example, an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc. Examples of the acylamino group include an acylamino group having a total of 2 to 12 carbon atoms, preferably a total of 2 to 8 carbon atoms, and more preferably an alkylcarbonylamino group having a total of 2 to 8 carbon atoms, such as an acetylamino group, a benzoylamino group, a 2-pyridinecarbonylamino group, a propanoylamino group, etc.

[0033] The aliphatic sulfonamide group, aromatic sulfonamide group, and heterocyclic sulfonamide group may be, for example, a methanesulfonamide group, a benzenesulfonamide group, or a 2-pyridinesulfonamide group.

[0034] The sulfamoyl group may have an aliphatic group, an aromatic group, a heterocyclic group, etc. Examples of the sulfamoyl group include a sulfamoyl group, an alkylsulfamoyl group having 1 to 9 carbon atoms in total, a dialkylsulfamoyl group having 2 to 10 carbon atoms in total, an arylsulfamoyl group having 7 to 13 carbon atoms in total, and a heterocyclic sulfamoyl group having 2 to 12 carbon atoms in total, more preferably a sulfamoyl group, an alkylsulfamoyl group having 1 to 7 carbon atoms in total, a dialkylsulfamoyl group having 3 to 6 carbon atoms in total, an arylsulfamoyl group having 6 to 11 carbon atoms in total, and a heterocyclic sulfamoyl group having 2 to 10 carbon atoms in total, such as a sulfamoyl group, a methylsulfamoyl group, an N,N-dimethylsulfamoyl group, a phenylsulfamoyl group, and a 4-pyridine sulfamoyl group.

[0035] The aliphatic oxy group may be saturated or unsaturated and may have a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, a methoxyethoxy group, etc. Examples of the aliphatic oxy group include alkoxy groups having a total of 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, such as a methoxy group, an ethoxy group, an i-propyloxy group, a cyclohexyloxy group, and a methoxyethoxy group.

[0036] The aromatic amino group and heterocyclic amino group may have an aliphatic group, an aliphatic oxy group, a halogen atom, a carbamoyl group, a heterocyclic group fused with the aryl group, an aliphatic oxycarbonyl group, preferably an aliphatic group having 1 to 4 carbon atoms in total, an aliphatic oxy group having 1 to 4 carbon atoms in total, a halogen atom, a carbamoyl group having 1 to 4 carbon atoms in total, a nitro group, or an aliphatic oxycarbonyl group having 2 to 4 carbon atoms in total.

[0037] The aliphatic thio group may be saturated or unsaturated and includes alkylthio groups having a total of 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, such as a methylthio group, an ethylthio group, a carbamoylmethylthio group, and a t-butylthio group.

[0038] The carbamoylamino group may have an aliphatic group, an aryl group, a heterocyclic group, etc. Examples of the carbamoylamino group include a carbamoylamino group, an alkylcarbamoylamino group having 2 to 9 carbon atoms in total, a dialkylcarbamoylamino group having 3 to 10 carbon atoms in total, an arylcarbamoylamino group having 7 to 13 carbon atoms in total, and a heterocyclic carbamoylamino group having 3 to 12 carbon atoms in total, preferably a carbamoylamino group, an alkylcarbamoylamino group having 2 to 7 carbon atoms in total, a dialkylcarbamoylamino group having 3 to 6 carbon atoms in total, an arylcarbamoylamino group having 7 to 11 carbon atoms in total, and a heterocyclic carbamoylamino group having 3 to 10 carbon atoms in total, such as a carbamoylamino group, a methylcarbamoylamino group, an N,N-dimethylcarbamoylamino group, a phenylcarbamoylamino group, and a 4-pyridinecarbamoylamino group.

[0039] In this disclosure, ranges expressed by endpoints include all numbers subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0040] In this disclosure, the term "at least 1" includes all numbers greater than or equal to 1 (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0041] Next, the coating composition of the present disclosure will be described in detail.

[0042] The first coating composition of the present disclosure contains a fluororesin, a polymer (I) containing polymerized units (I) based on a monomer represented by general formula (I), and an aqueous medium, and the content of the polymer (I) is 2000 mass ppm or less relative to the composition.

[0043] The viscosity of the first coating composition of the present disclosure is preferably 50 to 1000 mPa·s. The viscosity of the first coating composition of the present disclosure is more preferably 100 mPa·s or higher, even more preferably 110 mPa·s or higher, particularly preferably 120 mPa·s or higher, more preferably 900 mPa·s or lower, and even more preferably 750 mPa·s or lower. Coating compositions with viscosities within the above ranges are excellent at inhibiting aggregation during stirring and also suppressing molding defects such as dripping during application, thereby producing beautiful coating films. Herein, the viscosity of the coating composition is measured using a Brookfield viscometer with a No. 2 rotor at a liquid temperature of 25°C and 60 rpm.

[0044] The first coating composition of the present disclosure preferably has a stability retention time of 10 minutes or more as measured by a stirring test. Preferred stability retention times are, in order of preference, 10 minutes or more, 12 minutes or more, 15 minutes or more, 20 minutes or more, and 30 minutes or more. Coating compositions having stability retention times within the above ranges have excellent aggregation suppression properties during stirring. The upper limit of the stability retention time is not particularly limited, but is usually 120 minutes or less. In this specification, the stability retention time is measured by the stirring test described in the Examples.

[0045] The first coating composition of the present disclosure preferably further contains a nonionic surfactant. By including a nonionic surfactant, the coating composition has excellent agglomeration suppression properties during stirring, and molding defects such as dripping during application are suppressed. Excellent agglomeration suppression properties during stirring make it difficult for aggregates to adhere to the resulting coating film, making it easy to obtain a coating film with excellent film thickness uniformity. Furthermore, excellent agglomeration suppression properties during stirring can suppress large aggregates from adhering to the inside of the narrow nozzle or the tip of the nozzle of the spray gun during spray application, allowing for highly efficient spray application.

[0046] The first coating composition of the present disclosure preferably further contains an anionic hydrocarbon surfactant, which provides the coating composition with excellent aggregation suppression properties during stirring and suppresses molding defects such as dripping during application.

[0047] The second coating composition of the present disclosure is a coating composition containing a fluororesin and an aqueous medium, and has a stability retention time of 10 minutes or more as measured by a stirring test and a viscosity of 50 mPa·s or more and 1000 mPa·s or less.

[0048] The second coating composition of the present disclosure is excellent in inhibiting aggregation during stirring and inhibiting molding defects such as dripping during application, making it possible to produce a beautiful coating film. Furthermore, even when the coating composition contains a relatively large amount of fluororesin, the second coating composition of the present disclosure is excellent in inhibiting aggregation during stirring and inhibiting molding defects such as dripping during application, making it possible to produce a beautiful coating film with high efficiency.

[0049] The preferred stability retention times of the second coating composition of the present disclosure are, in order of preference, 12 minutes or more, 15 minutes or more, 20 minutes or more, and 30 minutes or more. A coating composition having a stability retention time within the above range has even better aggregation suppression properties during stirring. The upper limit of the stability retention time is not particularly limited, but is usually 120 minutes or less.

[0050] The second coating composition of the present disclosure has a viscosity of 50 to 1000 mPa·s. The viscosity of the second coating composition of the present disclosure is preferably 100 mPa·s or more, more preferably 110 mPa·s or more, and even more preferably 120 mPa·s or more, and is preferably 900 mPa·s or less, and more preferably 750 mPa·s or less. Having a viscosity within the above range allows the coating composition to have even better suppression of aggregation during stirring, and further reduces molding defects such as dripping during application.

[0051] The second coating composition of the present disclosure preferably further contains a polymer (I) containing polymerized units (I) based on a monomer represented by general formula (I). By containing the polymer (I), the aggregation suppression properties of the coating composition during stirring can be further improved.

[0052] The second coating composition of the present disclosure preferably further contains a nonionic surfactant, which provides the coating composition with better suppression of aggregation during stirring and further suppresses molding defects such as dripping during application.

[0053] The second coating composition of the present disclosure preferably further contains an anionic hydrocarbon surfactant, which provides the coating composition with even better suppression of aggregation during stirring and further suppresses molding defects such as dripping during application.

[0054] A third coating composition of the present disclosure contains a fluororesin, a nonionic surfactant, an anionic hydrocarbon surfactant, and an aqueous medium, and is substantially free of a fluorine-containing compound having a hydrophilic group.

[0055] There is a need for a coating composition that is substantially free of fluorine-containing compounds having hydrophilic groups and that has excellent aggregation-inhibiting properties during stirring. The third composition of the present disclosure is substantially free of fluorine-containing compounds having hydrophilic groups, but contains a nonionic surfactant and an anionic hydrocarbon surfactant, and therefore has excellent aggregation-inhibiting properties during stirring.

[0056] The third coating composition of the present disclosure preferably further contains a polymer (I) containing polymerized units (I) based on a monomer represented by general formula (I). By containing the polymer (I), the aggregation suppression properties of the coating composition during stirring can be further improved.

[0057] The third coating composition of the present disclosure has a suitable stability retention time similar to that of the first coating composition of the present disclosure, and a suitable viscosity similar to that of the first coating composition of the present disclosure.

[0058] The coating composition of the present disclosure preferably has a solids concentration of 20 to 50% by mass, more preferably 22% by mass or more, even more preferably 30% by mass or more, more preferably 48% by mass or less, and even more preferably 45% by mass or less. When the solids concentration is within the above range, a coating film having even better adhesion to the substrate and even better non-stick properties can be formed. In the present disclosure, the solids concentration of the coating composition is the concentration of the residue after heating at 380°C, and specifically, it can be measured by the method described in the examples.

[0059] The coating composition of the present disclosure may have a viscosity of 150 mPa·s or more and 500 mPa·s or less, from the viewpoint of being able to improve film-forming properties when the solid content concentration of the coating composition is high.

[0060] The configuration of the coating composition of the present disclosure will be described in more detail below.

[0061] <Fluoropolymer> The coating composition of the present disclosure (in this disclosure, the first coating composition, second coating composition, and third coating composition of the present disclosure may be referred to as the "coating composition of the present disclosure") contains a fluororesin.

[0062] The fluororesin is not particularly limited as long as it contains fluorine atoms, and examples thereof include polytetrafluoroethylene (PTFE) and fluororesins other than PTFE.

[0063] Examples of fluororesins other than PTFE include tetrafluoroethylene (TFE) / hexafluoropropylene (HFP) copolymer (FEP), TFE / perfluoro(alkyl vinyl ether) (PAVE) copolymer (PFA), TFE / perfluoroallyl ether copolymer, ethylene / TFE copolymer (ETFE), ethylene / chlorotrifluoroethylene (CTFE) copolymer (ECTFE), polychlorotrifluoroethylene (PCTFE), ethylene / TFE / HFP copolymer (EFEP), polyvinylidene fluoride (PVDF), vinylidene fluoride (VDF) copolymer, polyvinyl fluoride (PVF), etc. The fluororesins may be used alone or in combination of two or more.

[0064] In the coating composition of the present disclosure, the fluororesin is preferably at least one selected from PTFE, FEP, PFA, ETFE, and ECTFE, more preferably at least one selected from PTFE, FEP, and PFA, and even more preferably one containing PTFE.

[0065] A preferred embodiment of PTFE as the fluororesin will be described later.

[0066] In one embodiment of the coating composition of the present disclosure, at least PTFE is contained as the fluororesin. The coating composition of the present disclosure may contain only PTFE as the fluororesin, or may contain PTFE and a fluororesin other than PTFE as the fluororesin. For example, the coating composition of the present disclosure may contain PTFE and at least one selected from the group consisting of FEP and PFA as the fluororesin.

[0067] When the coating composition of the present disclosure contains PTFE, the PTFE content in the coating composition of the present disclosure is preferably 10.0% by mass or more and 52.0% by mass or less. The preferred lower limit of the PTFE content is, in order of preference, 15.0% by mass or more, 16.0% by mass or more, 18.0% by mass or more, and 20.0% by mass or more. The upper limit of the PTFE content is more preferably 50.0% by mass or less, and even more preferably 48.0% by mass or less.

[0068] In one embodiment of the coating composition of the present disclosure, the PTFE content in the coating composition is 30.0% by mass or more and 52.0% by mass or less. In this case, the PTFE content in the coating composition is more preferably 32.0% by mass or more, even more preferably 35.0% by mass or more, more preferably 50.0% by mass or less, and even more preferably 48.0% by mass or less. By having the PTFE content in the coating composition within the above range, a coating film with a high PTFE content can be easily obtained with high efficiency.

[0069] In the coating composition of the present disclosure, the amount of PTFE present in the fluororesin is preferably 55.0% by mass or more, more preferably 60.0% by mass or more, and even more preferably 65.0% by mass or more, and may be 100.0% by mass or less.

[0070] In one embodiment of the coating composition of the present disclosure, the content of PTFE in the coating composition is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and preferably 100% by mass or less, relative to the mass of the fluororesin in the coating composition. Furthermore, the coating composition of the present disclosure may contain only PTFE as the fluororesin.

[0071] In one embodiment of the first coating composition of the present disclosure, the amount of PTFE present in the fluororesin is 90.0 mass% or more. In this case, the amount of PTFE present in the fluororesin is more preferably 95.0 mass% or more, even more preferably 96.0 mass% or more, and may be 100.0 mass%. By having the amount of PTFE present in the fluororesin within the above range, a coating film with a high PTFE content can be easily obtained with high efficiency.

[0072] Although the FEP is not particularly limited, a copolymer having a molar ratio of TFE units to HFP units (TFE units / HFP units) of 70 / 30 or more and less than 99 / 1 is preferred. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and an even more preferred molar ratio is 80 / 20 or more and 98.9 / 1.1 or less. If the TFE unit content is too low, mechanical properties tend to decrease, while if the TFE unit content is too high, the melting point tends to become too high and film-forming properties tend to decrease. It is also preferred that the FEP is a copolymer containing 0.1 to 10 mol % of monomer units derived from monomers copolymerizable with TFE and HFP, and 90 to 99.9 mol % of TFE units and HFP units in total. Examples of monomers copolymerizable with TFE and HFP include PAVE and alkyl perfluorovinyl ether derivatives.

[0073] The melting point of FEP is preferably 150 to less than 322°C, more preferably 200 to 320°C, even more preferably 200 to 300°C, and particularly preferably 215 to 280°C.

[0074] The thermal decomposition starting temperature of FEP is preferably 360° C. or higher, more preferably 380° C. or higher, and even more preferably 390° C. or higher.

[0075] When the coating composition of the present disclosure contains FEP, the content of FEP in the coating composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and preferably 70.0% by mass or less, more preferably 60.0% by mass or less, even more preferably 52.0% by mass or less, and particularly preferably 50.0% by mass or less. In one embodiment, the content of FEP is preferably 0.1 to 20.0% by mass, more preferably 0.5 to 15.0% by mass, and even more preferably 1.0 to 50.0% by mass.

[0076] In the present disclosure, the thermal decomposition onset temperature is the temperature at which a 10 mg sample loses 1% by mass when heated from room temperature at a heating rate of 10°C / min using a differential thermal / thermogravimetric analyzer (TG-DTA) (product name: TG / DTA6200, manufactured by Seiko Electronics Co., Ltd.).

[0077] Although there are no particular limitations on the PFA, a copolymer in which the molar ratio of TFE units to PAVE units (TFE units / PAVE units) is 70 / 30 or more and less than 99 / 1 is preferred. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and an even more preferred molar ratio is 80 / 20 or more and 98.9 / 1.1 or less. If the TFE units are too few, the mechanical properties tend to decrease, while if the TFE units are too many, the melting point tends to become too high and film-forming properties tend to decrease. It is also preferred that the PFA is a copolymer in which the monomer units derived from monomers copolymerizable with TFE and PAVE are 0.1 to 10 mol % and the total of TFE units and PAVE units is 90 to 99.9 mol %. Examples of monomers copolymerizable with TFE and PAVE include HFP, CZ 3 Z 4 =CZ 5 (CF2) n Z 6 (In the formula, Z 3 , Z 4 and Z 5 are the same or different and represent a hydrogen atom or a fluorine atom; Z 6represents a hydrogen atom, a fluorine atom or a chlorine atom, and n represents an integer of 2 to 10.) and a vinyl monomer represented by CF2=CF-OCH2-Rf 7 (In the formula, Rf 7 represents a perfluoroalkyl group having 1 to 5 carbon atoms.

[0078] The melting point of PFA is preferably from 180 to less than 322°C, more preferably from 230 to 320°C, and even more preferably from 280 to 320°C.

[0079] The thermal decomposition starting temperature of PFA is preferably 380° C. or higher, more preferably 400° C. or higher, and even more preferably 410° C. or higher.

[0080] When the coating composition of the present disclosure contains PFA, the content of PFA in the coating composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and preferably 70.0% by mass or less, more preferably 60.0% by mass or less, even more preferably 52.0% by mass or less, and particularly preferably 50.0% by mass or less. In one embodiment, the content of PFA is preferably 0.1 to 20.0% by mass, more preferably 0.5 to 15.0% by mass, and even more preferably 1.0 to 10.0% by mass.

[0081] The content of each monomer unit in fluororesins (PTFE and fluororesins other than PTFE) can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of monomer.

[0082] In the coating composition of the present disclosure, the content of the fluororesin is preferably 15.0 to 52.0 mass% of the coating composition. The content of the fluororesin is more preferably 16 mass% or more, even more preferably 18.0 mass% or more, particularly preferably 20.0 mass% or more, most preferably 30.0 mass% or more, more preferably 50.0 mass% or less, and even more preferably 48.0 mass% or less. The content of the fluororesin in the coating composition can be determined as the solids concentration of the coating composition.

[0083] In one embodiment of the coating composition of the present disclosure, at least FEP is contained as the fluororesin. The coating composition of the present disclosure may contain only FEP as the fluororesin, or may contain FEP and a fluororesin other than FEP as the fluororesin.

[0084] In one embodiment of the coating composition of the present disclosure, at least PFA is contained as the fluororesin. The coating composition of the present disclosure may contain only PFA as the fluororesin, or may contain PFA and a fluororesin other than PFA as the fluororesin.

[0085] <Polytetrafluoroethylene (PTFE)> In one embodiment of the coating composition of the present disclosure, the fluororesin contains polytetrafluoroethylene (PTFE).

[0086] Polytetrafluoroethylene (PTFE) generally has extensibility, fibrillation properties, and non-melt fabrication processability, which means that the melt flow rate cannot be measured at a temperature higher than the crystallization melting point in accordance with ASTM D 1238 and D 2116, i.e., the PTFE does not flow easily even in the melting temperature range.

[0087] The PTFE may be a tetrafluoroethylene (TFE) homopolymer, or may be a modified PTFE containing TFE units and modified monomer units.

[0088] The modifying monomer is not particularly limited as long as it is copolymerizable with TFE, and examples thereof include fluoromonomers and non-fluoromonomers.

[0089] The non-fluoromonomer is not particularly limited and may be selected from the group consisting of monomers having the general formula: CH2=CR Q1 -LR Q2 (In the formula, R Q1 represents a hydrogen atom or an alkyl group. L represents a single bond, -CO-O-*, -O-CO-* or -O-. * represents R Q2 R represents the bond position with Q2 represents a hydrogen atom, an alkyl group or a nitrile group.

[0090] Examples of non-fluoromonomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, vinyl methacrylate, vinyl acetate, acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, ethyl vinyl ether, cyclohexyl vinyl ether, etc. Of these, butyl methacrylate, vinyl acetate, and acrylic acid are preferred as non-fluoromonomers.

[0091] Examples of fluoromonomers include perfluoroolefins such as hexafluoropropylene (HFP); chlorofluoroolefins such as chlorotrifluoroethylene (CTFE); hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride (VDF); fluoro(alkyl vinyl ether); (perfluoroalkyl)ethylene; and perfluoroallyl ether.

[0092] The modifying monomer used may be one type or multiple types.

[0093] The fluoro(alkyl vinyl ether) is not particularly limited, and examples thereof include fluoro(alkyl vinyl ethers) represented by the general formula (A): CF2=CF-ORf (A) (wherein Rf represents a perfluoroorganic group). In the present disclosure, the "perfluoroorganic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The perfluoroorganic group may have an ether oxygen.

[0094] An example of the fluoro(alkyl vinyl ether) is perfluoro(alkyl vinyl ether) (PAVE) represented by the general formula (A), where Rf is a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 5.

[0095] Examples of the perfluoroalkyl group in PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group.

[0096] Further, the fluoro(alkyl vinyl ether) includes those in which Rf in the general formula (A) is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms, and those in which Rf is the following formula:

[0097] [ka]

[0098] (wherein m represents 0 or an integer of 1 to 4), and Rf is a group represented by the following formula:

[0099] CF3CF2CF2-(O-CF(CF3)-CF2) n - (wherein n represents an integer of 1 to 4).

[0100] Examples of hydrogen-containing fluoroolefins include CH2=CF2, CFH=CH2, CFH=CF2, CH2=CFCF3, CH2=CHCF3, CHF=CHCF3 (E-isomer), and CHF=CHCF3 (Z-isomer).

[0101] The fluoro(alkyl vinyl ether) is preferably at least one selected from the group consisting of perfluoro(methyl vinyl ether) (PMVE), perfluoro(ethyl vinyl ether) (PEVE) and perfluoro(propyl vinyl ether) (PPVE), and more preferably PMVE.

[0102] The (perfluoroalkyl)ethylene (PFAE) is not particularly limited, and examples thereof include (perfluorobutyl)ethylene (PFBE), (perfluorohexyl)ethylene, and (perfluorooctyl)ethylene.

[0103] Examples of perfluoroallyl ethers include: General formula: CF2=CF-CF2-ORf (wherein Rf represents a perfluoro organic group).

[0104] Rf in the above general formula is the same as Rf in general formula (A). Rf is preferably a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms. The perfluoroallyl ether is preferably at least one selected from the group consisting of CF2=CF-CF2-O-CF3, CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9, more preferably at least one selected from the group consisting of CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9, and even more preferably CF2=CF-CF2-O-CF2CF2CF3.

[0105] The content of the modified monomer unit in the modified PTFE is preferably in the range of 0.00001 to 1.0% by mass relative to the total polymerized units. The lower limit is preferably 0.0001% by mass, more preferably 0.001% by mass, and even more preferably 0.005% by mass. The upper limit of the content of the modified monomer unit is, in order of preference, 0.90% by mass, 0.50% by mass, 0.30% by mass, 0.20% by mass, 0.15% by mass, 0.10% by mass, and 0.05% by mass. In the present disclosure, the modified monomer unit refers to a portion of the molecular structure of the modified PTFE that is derived from the modified monomer.

[0106] A preferred example of the modifying monomer is a comonomer (3) having a monomer reactivity ratio of 0.1 to 8. The presence of the comonomer (3) makes it possible to obtain PTFE particles with a small particle size, and to obtain a coating composition that is excellent in inhibiting aggregation during stirring.

[0107] Here, the monomer reactivity ratio in copolymerization with TFE is the value obtained by dividing the rate constant when the propagating radical reacts with TFE when the propagating radical is less than a repeating unit based on TFE by the rate constant when the propagating radical reacts with a comonomer. The lower this value, the higher the reactivity of the comonomer with TFE. The monomer reactivity ratio can be calculated by copolymerizing TFE and a comonomer, determining the composition in the resulting polymer immediately after the start of copolymerization, and using the Feynman-Ross equation.

[0108] The copolymerization was carried out in a 6.0 L stainless steel autoclave using 3600 g of deionized, degassed water, 1000 ppm by mass of ammonium perfluorooctanoate relative to the water, and 100 g of paraffin wax at a pressure of 0.78 MPaG and a temperature of 70°C. 0.05 g, 0.1 g, 0.2 g, 0.5 g, and 1.0 g of comonomer were added to the reactor, respectively, and 0.072 g of ammonium persulfate (20 ppm by mass relative to the water) was added. TFE was continuously fed to maintain the polymerization pressure at 0.78 MPaG. When the TFE charge reached 1000 g, stirring was stopped and the reactor was depressurized until atmospheric pressure was reached. After cooling, the paraffin wax was separated to obtain an aqueous dispersion containing the product polymer. The aqueous dispersion was stirred to coagulate the product polymer, which was then dried at 150°C. The composition of the resulting polymer is calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of monomer.

[0109] The comonomer (3) having a monomer reactivity ratio of 0.1 to 8 is preferably at least one selected from the group consisting of comonomers represented by formulas (3a) to (3d). CH2=CH-Rf 1 (3a) (In the formula, Rf 1 is a perfluoroalkyl group having 1 to 10 carbon atoms. CF2=CF-O-Rf 2 (3b) (In the formula, Rf 2 is a perfluoroalkyl group having 1 to 2 carbon atoms. CF2=CF-O-(CF2) n CF=CF2(3c) (wherein n is 1 or 2).

[0110] [ka] (In the formula, X 3 and X 4 is F, Cl or a methoxy group, and Y is of formula Y1 or Y2.

[0111] [ka] (In formula Y2, Z and Z′ are F or a fluorinated alkyl group having 1 to 3 carbon atoms.)

[0112] The content of the comonomer (3) units is preferably in the range of 0.00001 to 1.0% by mass relative to the total polymerized units of the modified PTFE. The lower limit is more preferably 0.0001% by mass, even more preferably 0.001% by mass, even more preferably 0.005% by mass, and particularly preferably 0.009% by mass. The upper limit is, in order of preference, 0.90%, 0.50%, 0.40%, 0.30%, 0.20%, 0.15%, 0.10%, 0.08%, 0.05%, and 0.01% by mass.

[0113] The modified monomer is preferably at least one selected from the group consisting of hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, fluoro(alkyl vinyl ether), (perfluoroalkyl)ethylene, ethylene, and modified monomers having a functional group reactive by radical polymerization and a hydrophilic group, because it can provide a coating composition with a small average primary particle size, a small aspect ratio of the primary particles, and excellent aggregation suppression during stirring. By using the modified monomer, a coating composition with a smaller average primary particle size, a small aspect ratio of the primary particles, and excellent aggregation suppression during stirring can be obtained. Furthermore, a coating composition with less uncoagulated polymer can be obtained.

[0114] The modified monomer preferably includes a modified monomer having a functional group capable of reacting by radical polymerization and a hydrophilic group (hereinafter referred to as "modified monomer (A)").

[0115] The presence of the modifying monomer (A) allows the production of PTFE particles with a small primary particle size, resulting in a coating composition with excellent agglomeration suppression during stirring. It also reduces the amount of uncoagulated polymer. Furthermore, it reduces the aspect ratio of the primary particles.

[0116] PTFE containing TFE units and modified monomer (A) units can be obtained, for example, by polymerizing TFE and modified monomer (A) in an aqueous medium. The amount of modified monomer (A) used during polymerization is preferably more than an amount equivalent to 0.1 ppm by mass of the aqueous medium, more preferably more than 0.5 ppm by mass, even more preferably more than 1.0 ppm by mass, even more preferably 5 ppm by mass or more, and particularly preferably 10 ppm by mass or more. If the amount of modified monomer (A) used is too small, the average primary particle diameter of the resulting PTFE may not be small. The amount of modified monomer (A) used may be within the above range, but the upper limit can be set to, for example, 5,000 ppm by mass.

[0117] Since the modified monomer (A) is highly water-soluble, even if the coating composition contains unreacted modified monomer (A), the modified monomer (A) can be easily removed from the coating composition by methods such as concentration, coagulation, and washing.

[0118] Examples of the hydrophilic group in the modified monomer (A) include -NH, -PO, -P(O)(OM), -OPO, -OP(O)(OM), -SO, -OSO, and -COOM (in each formula, M represents H, a metal atom, or NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring.) Of these, -SO3M or -COOM is preferred as the hydrophilic group. R 7The organic group in the formula (I) is preferably an alkyl group. R 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred are alkyl groups of the formula: The metal atom may be a monovalent or divalent metal atom, such as an alkali metal (Group 1) or an alkaline earth metal (Group 2), with Na, K, or Li being preferred.

[0119] Examples of the "functional group capable of reacting by radical polymerization" in the modifying monomer (A) include groups having an ethylenically unsaturated bond, such as a vinyl group and an allyl group. The group having an ethylenically unsaturated bond is a group represented by the following formula: CX e X g =CX f R- (In the formula, X e , X f and X g are each independently F, Cl, H, CF3, CF2H, CFH2, or CH3; and R is a linking group. The linking group for R can be represented by the formula: a Preferred linking groups include -CH=CH2 and -CF=CH 2、 -CH=CF 2、 Examples include groups having an unsaturated bond such as -CF=CF2, -CH2-CH=CH2, -CF2-CF=CH2, -CF2-CF=CF2, -(C=O)-CH=CH2, -(C=O)-CF=CH2, -(C=O)-CH=CF2, -(C=O)-CF=CF2, -(C=O)-C(CH3)=CH2, -(C=O)-C(CF3)=CH2, -(C=O)-C(CH3)=CF2, -(C=O)-C(CF3)=CF2, -O-CH2-CH=CH2, -O-CF2-CF=CH2, -O-CH2-CH=CF2, and -O-CF2-CF=CF2.

[0120] Since the modified monomer (A) has a functional group that can react in radical polymerization, it is presumed that when used in polymerization, it reacts with TFE in the early stages of the polymerization reaction, forming highly stable particles that have hydrophilic groups derived from the modified monomer (A).For this reason, it is thought that the number of particles increases when polymerization is carried out in the presence of the modified monomer (A).

[0121] The polymerization may be carried out in the presence of one type of the modifying monomer (A), or in the presence of two or more types.

[0122] In the polymerization, a compound having an unsaturated bond can be used as the modifying monomer (A).

[0123] The modifying monomer (A) is represented by the general formula (4A): CX i X k =CX j R a -(CZ 1 Z 2 ) k -Y 3 (4A) (In the formula, X i , X j and X k are each independently F, Cl, H, or CF; Y 3 is a hydrophilic group; R a is a linking group; Z 1 and Z 2 are independently H, F or CF3, and k is 0 or 1). Examples of the hydrophilic group include -NH, -PO, -P(O)(OM), -OPO, -OP(O)(OM), -SO, -OSO, and -COOM (in each formula, M represents H, a metal atom, or NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring. ) are examples of the hydrophilic group. Of these, -SO3M or -COOM is preferred. R 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred are alkyl groups of the formula: The metal atom may be a monovalent or divalent metal atom, such as an alkali metal (Group 1) or an alkaline earth metal (Group 2), with Na, K, or Li being preferred. By using the modified monomer (4A), it is possible to obtain a coating composition having a smaller average primary particle size and better aggregation suppression properties during stirring. It is also possible to further reduce the aspect ratio of the primary particles.

[0124] Above R a is a linking group. In the present disclosure, "linking group" refers to a divalent linking group. The linking group may be a single bond and preferably contains at least one carbon atom, and the number of carbon atoms may be 2 or more, 4 or more, 8 or more, 10 or more, or 20 or more. There is no upper limit, but it may be, for example, 100 or less, or 50 or less. The linking group may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and may optionally contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and may optionally contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The linking group may not contain carbon atoms but may be a catenary heteroatom such as oxygen, sulfur, or nitrogen.

[0125] Above R a is preferably a catenary heteroatom such as oxygen, sulfur, or nitrogen, or a divalent organic group. R aWhen R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced with a halogen other than fluorine, such as chlorine, and may or may not contain a double bond. a may be either linear or branched, and may be either cyclic or acyclic. a may contain functional groups (e.g., esters, ethers, ketones, amines, halides, etc.). R a may also be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group. R a Examples of the hydrocarbon group include a hydrocarbon group in which no fluorine atoms are bonded to a carbon atom, a hydrocarbon group in which some of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, a hydrocarbon group in which all of the hydrogen atoms bonded to a carbon atom are substituted with fluorine atoms, -(C=O)-, -(C=O)-O-, or a hydrocarbon group containing an ether bond, which may contain an oxygen atom, a double bond, or a functional group.

[0126] R a is preferably —(C═O)—, —(C═O)—O—, or a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond and may contain a carbonyl group, and in the hydrocarbon group, some or all of the hydrogen atoms bonded to the carbon atoms may be substituted with fluorine. R a Preferably, -(CH2) a -, -(CF2) a -, -O-(CF2) a -, -(CF2) a -O-(CF2) b -, -O(CF2) a -O-(CF2) b -, -(CF2) a -[O-(CF2) b ] c -, -O(CF2) a -[O-(CF2) b ] c -, -[(CF2) a -O] b-[(CF2) c -O] d -, -O[(CF2) a -O] b -[(CF2) c -O] d -, -O-[CF2CF(CF3)O] a -(CF2) b -, -(C=O)-, -(C=O)-O-, -(C=O)-(CH2) a -, -(C=O)-(CF2) a -, -(C=O)-O-(CH2) a -, -(C=O)-O-(CF2) a -, -(C=O)-[(CH2) a -O] b -, -(C=O)-[(CF2) a -O] b -, -(C=O)-O[(CH2) a -O] b -, -(C=O)-O[(CF2) a -O] b -, -(C=O)-O[(CH2) a -O] b -(CH2) c -, -(C=O)-O[(CF2) a -O] b -(CF2) c -, -(C=O)-(CH2) a -O-(CH2) b -, -(C=O)-(CF2) a -O-(CF2) b -, -(C=O)-O-(CH2) a -O-(CH2) b -, -(C=O)-O-(CF2) a -O-(CF2) b At least one selected from -, -(C=O)-O-C6H4-, and combinations thereof. In the formula, a, b, c, and d are independently at least 1. a, b, c, and d may independently be 2 or more, 3 or more, 4 or more, 10 or more, or 20 or more. The upper limit of a, b, c, and d is, for example, 100.

[0127] R a Specific examples of suitable alkyl groups include -CF2-O-, -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -CF2-O-CF2CF2-, -C F2-O-CF2CH2-, -CF2-O-CF2CF2CH2-, -CF2-O-CF (CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3) CF2-O-, -CF2-O-CF(CF3)CH2-, -(C=O)-, -(C=O) -O-, -(C=O)-(CH2)-, -(C=O)-(CF2)-, -(C=O)-O-(CH2)-, -(C=O)-O-(CF2)-, -(C=O)-[(CH2)2-O] n -, -(C=O)-[(CF2)2-O] n -, -(C=O)-O[(CH2)2-O] n -, -(C=O)-O[(CF2)2-O] n -, -(C=O)-O[(CH2)2-O] n -(CH2)-, -(C=O)-O[(CF2)2-O] n -(CF2)-, -(C=O)-(CH2)2-O-(CH2)-, -(C=O)-(CF2)2-O-(CF2)-, -(C=O)-O-(CH2)2-O-(CH2)-, -(C=O)-O-(CF2)2-O-(CF2)-, -(C=O)-O-C6H4-, etc. a Specifically, -CF2-O-, -CF2-O-CF2-, -CF2-O-CF2CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2 -O-CF(CF3)CF2-O-, -(C=O)-, -(C=O)-O-, -(C=O)-(CH2)-, -(C=O)-O-(CH2)-, -(C=O)-O[(CH2)2-O] n -, -(C=O)-O[(CH2)2-O] n -(CH2)-, -(C=O)-(CH2)2-O-(CH2)-, or -(C=O)-O-C6H4- is preferred. In the above formula, n is an integer of 1 to 10.

[0128] -R in general formula (4A) a -(CZ 1 Z 2 ) k -Examples of - include -CF2-O-CF2-, -CF2-O-CF(CF3)-, -CF2-O-C(CF3)2-, -CF2-O-CF2-CF2-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2-C(CF3)2-, -CF2-O-CF2CF2-CF2-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF2CF2-C(CF3)2-, -CF2-O-CF(CF3)-CF2-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C(CF3)2-, -CF2-O-CF(CF3)CF2-CF2-, -CF2-O-CF(CF3)CF2-CF(CF3)-, -CF2-O-CF(CF3)CF2-C(CF3)2-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-O-C(CF3)2-, -(C=O)-, -(C=O)-O-, -(C=O)-(CH2)-, -(C=O)-(CF2)-, -(C=O)-O-(CH2)-, -(C=O)-O-(CF2)-, -(C=O)-[(CH2)2-O] n -(CH2)-, -(C=O)-[(CF2)2-O] n -(CF2)-, -(C=O)-[(CH2)2-O] n -(CH2)-(CH2)-, -(C=O)-[(CF2)2-O] n -(CF2)-(CF2)-, -(C=O)-O[(CH2)2-O] n -(CF2)-, -(C=O)-O[(CH2)2-O] n -(CH2)-(CH2)-, -(C=O)-O[(CF2)2-O] n -(CF2)-, -(C=O)-O[(CF2)2-O] n-(CF2)-(CF2)-, -(C=O)-(CH2)2-O-(CH2)-(CH2)-, -(C=O)-(CF2)2-O-(CF2)-(CF2)-, -(C=O)-O-(CH2)2-O-(CH2)-(CH2)-, -(C=O )-O-(CF2)2-O-(CF2)-(CF2)-, -(C=O)-O-(CH2)2-O-(CH2)-C(CF3)2-, -(C=O)-O-(CF2)2-O-(CF2)-C(CF3)2-, or -(C=O)-O-C6H4- C(CF3)2- is preferred, -CF2-O-CF(CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(C F3)CF2-CF(CF3)-, -CF2-O-CF(CF3)CF2-O-CF(CF3)-, -(C=O)-, -(C=O)-O-(CH2)-, -(C=O)-O-(CH2)-(CH2)-, -(C=O)-O[(CH2)2-O] n -(CH2)-(CH2)-, -(C=O)-O-(CH2)2-O-(CH2)-C(CF3)2-, or -(C=O)-O-C6H4-C(CF3)2- is more preferred. In the above formula, n is an integer of 1 to 10.

[0129] Specific examples of the compound represented by general formula (4A) include: [ka] (In the formula, X j and Y 3 is the same as above. n is an integer of 1 to 10.

[0130] R a As the general formula (r1): -(C=O) h -(O) i -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g - (r1) (In the formula, X 6are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, and i is 0 or 1), and a divalent group represented by the general formula (r2): -(C=O) h -(O) i -CF2-O-(CX 7 2) e -(O) g - (r2) (In the formula, X 7 are each independently H, F or CF3, e is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, and i is 0 or 1. Divalent groups represented by the following formula are also preferred.

[0131] -R in general formula (4A) a -(CZ 1 Z 2 ) k - also has the general formula (t1): -(C=O) h -(O) i -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 - (t1) (In the formula, X 6 are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, i is 0 or 1, and Z 1 and Z 2 are each independently F or CF3), and in formula (t1), Z 1 and Z 2 More preferably, one is F and the other is CF3. In addition, in the general formula (4A), -R a -(CZ 1 Z 2 ) k - as the general formula (t2): -(C=O) h -(O) i-CF2-O-(CX 7 2) e -(O) g -CZ 1 Z 2 - (t2) (In the formula, X 7 are each independently H, F, or CF3, e is an integer of 0 to 3, g is 0 or 1, h is 0 or 1, i is 0 or 1, and Z 1 and Z 2 are each independently F or CF3), and in formula (t2), Z 1 and Z 2 More preferably, one is F and the other is CF3.

[0132] The compound represented by the general formula (4A) is a compound having a hydrophilic group (Y 3 ) except for the C—F bond and no C—H bond. That is, in the general formula (4A), X i , X j , and X k All of the are F and R a is preferably a perfluoroalkylene group having one or more carbon atoms, and the perfluoroalkylene group may be either linear or branched, may be cyclic or acyclic, and may contain at least one catenary heteroatom. The number of carbon atoms in the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0133] The compound represented by the general formula (4A) may be partially fluorinated. That is, the compound represented by the general formula (4A) may have a hydrophilic group (Y 3 ), it is also preferred that the alkyl group has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0134] The compound represented by general formula (4A) is also preferably a compound represented by the following formula (4A-a). CF2=CF-O-Rf 0 -Y 3 (4A-a) (In the formula, Y 3 is a hydrophilic group, and Rf 0 is a perfluorinated divalent linking group which may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and which optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen.

[0135] The compound represented by general formula (4A) is also preferably a compound represented by the following formula (4A-b). CH2=CH-O-Rf 0 -Y 3 (4A-b) (In the formula, Y 3 is a hydrophilic group, and Rf 0 is a perfluorinated divalent linking group defined by formula (4A-a).

[0136] In general formula (4A), Y 3 One of the preferred embodiments is -OSO3M. 3 is -OSO3M, examples of the compound represented by general formula (4A) include CF2=CF(OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(O(CF2)4CH2OSO3M), CF2=CF(OCF2CF(CF3)CH2OSO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(OCF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), and the like. In the above formulas, M is the same as above.

[0137] In general formula (4A), Y 3 Another preferred form is -SO3M. 3is -SO3M, examples of polymerized units based on the compound represented by general formula (4A) include CF2=CF(OCF2CF2SO3M), CF2=CF(O(CF2)4SO3M), CF2=CF(OCF2CF(CF3)SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2SO3M), CH2=CH(CF2CF2SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO3M), CH2=CH((CF2)4SO3M), CH2=CH(CF2CF2SO3M), CH2=CH((CF2)3SO3M), etc. In the above formulas, M is the same as above.

[0138] In general formula (4A), Y 3 -COOM is also a preferred form. 3 is -COOM, the compounds represented by general formula (4A) include CF2=CF(OCF2CF2COOM), CF2=CF(OCF2CF2CF2COOM), CF2=CF(O(CF2)5COOM), CF2=CF(OCF2CF(CF3)COOM), CF2=CF(OCF2CF(CF3)O(CF2) n COOM) (n is greater than 1), CH2=CH(CF2CF2COOM), CH2=CH((CF2)4COOM), CH2=CH(CF2CF2COOM), CH2=CH((CF2)3COOM), CF2=CF(OCF2CF2SO2NR'CH2COOM), CF2=CF(O(CF2)4SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)SO2NR'CH2COOM), CF2=CF(OCF2 CF(CF3)OCF2CF2SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)4SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)3SO2NR'CH2COOM), etc. In the above formula, R' is H or C 1-4 is an alkyl group, and M is the same as above.

[0139] In general formula (4A), Y 3 In another preferred embodiment, Y is -OPO3M or -OP(O)(OM)2. 3 is -OPO3M or -OP(O)(OM)2, examples of the compound represented by general formula (4A) include CF2=CF(OCF2CF2CH2OP(O)(OM)2), CF2=CF(O(CF2)4CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OP(O)(OM)2), CF2=CF(OCF2CF2SO2N(CH3 )CH2CH2OP(O)(OM)2), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2, CH2=CH((CF2)4CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2), CH2=CH((CF2)3CH2OP(O)(OM)2), etc. In the above formula, M is the same as above.

[0140] In general formula (4A), Y 3 In another preferred embodiment, Y is -PO3M or -P(O)(OM)2. 3 is -PO3M or -OP(O)(OM)2, examples of the compound represented by general formula (4A) include CF2=CF(OCF2CF2P(O)(OM)2), CF2=CF(O(CF2)4P(O)(OM)2), CF2=CF(OCF2CF(CF3)P(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)4P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)3P(O)(OM)2), and the like, where M is the same as above.

[0141] The compound represented by general formula (4A) includes compounds represented by general formula (5A): CX2=CY(-CZ2-O-Rf-Y 3 ) (5A) (In the formula, X's may be the same or different and each represent -H or -F; Y's may be -H, -F, an alkyl group or a fluorine-containing alkyl group; and Z's may be the same or different and each represent -H, -F, an alkyl group or a fluorine-containing alkyl group. Rf's may be a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. Y 3 is the same as above.), a compound represented by general formula (6A): CX2=CY(-O-Rf-Y 3 ) (6A) (In the formula, X may be the same or different and is -H or -F; Y is -H, -F, an alkyl group or a fluorine-containing alkyl group; and Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. Y 3 is the same as above.) and a compound represented by general formula (7A): CX2=CY(-Rf-Y 3 ) (7A) (In the formula, X may be the same or different and is -H or -F; Y is -H, -F, an alkyl group or a fluorine-containing alkyl group; and Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. Y 3 is the same as above.) The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and contains an ether bond between carbon atoms.

[0142] In general formula (5A), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0143] In general formula (5A), Y is -H, -F, an alkyl group or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F or -CF3, and more preferably -F.

[0144] In general formula (5A), Z's are the same or different and represent -H, -F, an alkyl group, or a fluoroalkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Z's are preferably -H, -F, or -CF3, and more preferably -F.

[0145] In general formula (5A), it is preferable that at least one of X, Y, and Z contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0146] In general formula (5A), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. The number of carbon atoms in the fluorine-containing alkylene group is preferably 2 or more. Also, it is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0147] The number of carbon atoms of the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The number of carbon atoms of the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, and even more preferably 12 or less. Examples of the fluorine-containing alkylene group having an ether bond include those represented by the following formula: [ka] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is also preferably a divalent group represented by the formula: H, F, or CF3; p1+q1+r1 is an integer of 1 to 10; s1 is 0 or 1; and t1 is an integer of 0 to 5). Specific examples of the fluorine-containing alkylene group having an ether bond include -CF(CF3)CF2-O-CF(CF3)-, -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer of 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n Examples include -CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0148] In general formula (5A), Y 3 is -COOM, -SO3M or -OSO3M (M is H, a metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring. 7The organic group in R is preferably an alkyl group. 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 The above-mentioned alkyl group is more preferred. The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K, or Li is preferred. The above-mentioned M is -H, a metal atom, or -NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or -NR 7 4 is more preferred, -H, -Na, -K, -Li or -NH4 is even more preferred, -Na, -K or -NH4 is even more preferred, -Na or -NH4 is particularly preferred, and -NH4 is most preferred. 3 As the alkyl group, -COOM or -SO3M is preferred, and -COOM is more preferred.

[0149] The compound represented by general formula (5A) is preferably a compound (5a) represented by general formula (5a). CH2=CF(-CF2-O-Rf-Y 3 ) (5a) (Wherein Rf and Y 3 is the same as above.)

[0150] Specific examples of the compound represented by the general formula (5a) include compounds represented by the following formula:

[0151] [ka]

[0152] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is H, F, or CF3; p1+q1+r1 are integers between 0 and 10; s1 is 0 or 1; t1 is an integer between 0 and 5; Y 3 is the same as above, except for Z 3 and Z 4are both H, then p1+q1+r1+s1 is not 0). More specifically, compounds represented by the following formula are exemplified:

[0153] [ka]

[0154] Among them,

[0155] [ka]

[0156] It is preferable that:

[0157] The compound represented by general formula (5a) includes compounds represented by formula (5a) 3 is preferably -COOM, and particularly preferably at least one selected from the group consisting of CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M is as defined above), and more preferably CH2=CFCF2OCF(CF3)COOM.

[0158] The compound represented by general formula (5A) is preferably a compound (5b) represented by general formula (5b). CX 2 2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-Y 3 (5b) (In the formula, each 2 are the same and represent F or H. n5 represents 0 or an integer of 1 to 10, and Y 3 is the same as the definition above.)

[0159] In the general formula (5b), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, from the viewpoint of the aggregation suppression properties of the resulting coating composition during stirring. 3is preferably -COOM in that it provides adequate water solubility and inhibits aggregation during stirring of the coating composition, and the above M is preferably H or NH4 in that it is less likely to remain as an impurity and improves the heat resistance of the resulting coating film.

[0160] Examples of the compound represented by general formula (5c) include CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M is as defined above).

[0161] Further, examples of the compound represented by general formula (5A) include a compound represented by general formula (5c).

[0162] CF2=CFCF2-O-Rf-Y 3 (5c) (Wherein Rf and Y 3 is the same as above)

[0163] More specifically, [ka] etc.

[0164] In general formula (6A), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0165] In general formula (6A), Y is -H, -F, an alkyl group or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F or -CF3, and more preferably -F.

[0166] In general formula (6A), it is preferable that at least one of X and Y contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0167] In general formula (6A), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond. The fluorine-containing alkylene group preferably has 2 or more carbon atoms. The fluorine-containing alkylene group preferably has 30 or less carbon atoms, more preferably 20 or less, and even more preferably 10 or less carbon atoms. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0168] In the above general formula (6A), Y 3 is -COOM, -SO3M or -OSO3M (M is H, a metal atom, NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring. R 7 The organic group in R is preferably an alkyl group. 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred are alkyl groups of the formula: The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), and is preferably Na, K or Li. The above M is —H, a metal atom, or —NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or -NR7 4 is more preferred, -H, -Na, -K, -Li or -NH4 is even more preferred, -Na, -K or -NH4 is even more preferred, -Na or -NH4 is especially preferred, and -NH4 is most preferred. Above Y 3 As the alkyl group, -COOM or -SO3M is preferred, and -COOM is more preferred.

[0169] The compound represented by general formula (6A) is preferably at least one selected from the group consisting of compounds represented by general formulae (6a), (6b), (6c), (6d) and (6e). CF2=CF-O-(CF2) n1 -Y 3 (6a) (wherein n1 represents an integer of 1 to 10, and Y 3 is the same as defined above. CF2=CF-O-(CF2C(CF3)F) n2 -Y 3 (6b) (wherein n2 represents an integer of 1 to 5, and Y 3 is the same as the definition above.) CF2=CF-O-(CFX 1 ) n3 -Y 3 (6c) (In the formula, X 1 represents F or CF3, n3 represents an integer of 1 to 10, and Y 3 is the same as the definition above.) CF2=CF-O-(CF2CFX 1 O) n4 -(CF2) n6 -Y 3 (6d) (wherein n4 represents an integer of 1 to 10, n6 represents an integer of 1 to 3, and Y 3 and X 1 is the same as the definition above.) CF2=CF-O-(CF2CF2CFX 1 O) n5 -CF2CF2CF2-Y 3 (6e) (wherein n5 represents an integer of 0 to 10, and Y 3 and X1 is the same as the definition above.)

[0170] In the general formula (6a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. 3 is preferably -COOM in that it provides adequate water solubility and excellent aggregation suppression properties during stirring of the coating composition, and M is preferably H or NH4 in that it is less likely to remain as an impurity and improves the heat resistance of the resulting coating film.

[0171] Examples of the compound represented by general formula (6a) include CF2=CF-O-CF2COOM, CF2=CF(OCF2CF2COOM), and CF2=CF(OCF2CF2CF2COOM) (wherein M is as defined above).

[0172] In the general formula (6b), n2 is preferably an integer of 3 or less from the viewpoint of the aggregation suppression property during stirring of the resulting coating composition, and Y 3 is preferably -COOM in that it provides adequate water solubility and excellent aggregation suppression properties during stirring of the coating composition, and M is preferably H or NH4 in that it is less likely to remain as an impurity and improves the heat resistance of the resulting coating film.

[0173] In the general formula (6c), n3 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably -COOM in that it provides suitable water solubility and excellent aggregation suppression properties during stirring of the coating composition, and the above M is preferably H or NH4 in that it provides good aggregation suppression properties during stirring.

[0174] In the general formula (6d), the X 1 is preferably -CF3 from the viewpoint of aggregation suppression during stirring of the coating composition, and n4 is preferably an integer of 5 or less from the viewpoint of water solubility, and Y 3 is preferably -COOM in that it provides suitable water solubility and excellent aggregation suppression properties during stirring of the coating composition, and the above M is preferably H or NH4.

[0175] Examples of compounds represented by general formula (6d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, and CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM (wherein M represents H, NH4, or an alkali metal).

[0176] In the general formula (6e), n5 is preferably an integer of 5 or less in terms of water solubility, and Y 3 is preferably -COOM in that it provides suitable water solubility and excellent aggregation suppression properties during stirring of the coating composition, and the above M is preferably H or NH4.

[0177] An example of the compound represented by general formula (6e) is CF2=CFOCF2CF2CF2COOM (wherein M represents H, NH4 or an alkali metal).

[0178] In general formula (7A), Rf is preferably a fluorine-containing alkylene group having a carbon number of 1 to 40. In general formula (7A), at least one of X and Y preferably contains a fluorine atom.

[0179] The compound represented by general formula (7A) is represented by general formula (7a): CF2=CF-(CF2) n1 -Y 3 (7a) (wherein n1 represents an integer of 1 to 10, and Y 3 is as defined above.) and a compound represented by general formula (7b): CF2=CF-(CF2C(CF3)F) n2 -Y 3 (7b) (wherein n2 represents an integer of 1 to 5, and Y 3 is as defined above. Preferably, at least one compound selected from the group consisting of compounds represented by Above Y 3 is preferably -SO3M or -COOM, and M is H, a metal atom, NR7 4. It is preferably an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 7 represents H or an organic group.

[0180] In the general formula (7b), n2 is preferably an integer of 3 or less from the viewpoint of the aggregation suppression property during stirring of the resulting coating composition, and Y 3 is preferably -COOM in that it provides adequate water solubility and excellent aggregation suppression properties during stirring of the coating composition, and M is preferably H or NH4 in that it is less likely to remain as an impurity and improves the heat resistance of the resulting coating film.

[0181] The above-mentioned modified monomer preferably contains modified monomer (A), and preferably contains at least one selected from the group consisting of compounds represented by general formula (5c), general formula (6a), general formula (6b), general formula (6c), and general formula (6d), and more preferably contains a compound represented by general formula (5c).

[0182] When the modifying monomer contains the above-mentioned modifying monomer (A), the content of the modifying monomer (A) units is preferably in the range of 0.00001 to 1.0% by mass relative to the total polymerized units of PTFE. The lower limit is preferably 0.0001% by mass, more preferably 0.001% by mass, even more preferably 0.005% by mass, and particularly preferably 0.009% by mass. The upper limit is, in order of preference, 0.90%, 0.50%, 0.40%, 0.30%, 0.20%, 0.15%, 0.10%, 0.08%, 0.05%, and 0.01% by mass.

[0183] In the present disclosure, the content of each compound unit constituting PTFE can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of compound. The content of each compound unit constituting PTFE can also be calculated from the amount of modified monomer added used in polymerization.

[0184] The PTFE may have a core-shell structure. Examples of PTFE having a core-shell structure include modified PTFE particles containing a core of high molecular weight PTFE and a shell of lower molecular weight PTFE or modified PTFE. Examples of such modified PTFE include the PTFE described in JP-A-2005-527652.

[0185] The average primary particle diameter of PTFE is preferably 150 nm or more, more preferably 180 nm or more. The larger the average primary particle diameter of PTFE, the more suppressed the increase in paste extrusion pressure when paste extrusion molding is performed using the powder, and the better the film-forming properties. The upper limit is not particularly limited, but may be 500 nm. From the viewpoint of productivity in the polymerization process, the upper limit is preferably 400 nm, more preferably 350 nm. The average primary particle diameter is determined by diluting an aqueous PTFE dispersion with water to a solids concentration of 0.15% by mass, measuring the transmittance of 550 nm incident light per unit length of the obtained diluted latex, and measuring the number-based average primary particle diameter determined by measuring the unidirectional diameter using a transmission electron microscope photograph, to create a calibration curve, and using this calibration curve to determine the actual transmittance of 550 nm incident light for each sample. The average primary particle size can be measured by dynamic light scattering. An aqueous dispersion with a solids concentration of approximately 1.0% by mass is prepared, and the average primary particle size is measured by dynamic light scattering at 25°C, with a solvent (water) refractive index of 1.3328 and a solvent (water) viscosity of 0.8878 mPa·s, and 70 cumulative measurements. For example, an ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.) can be used for the dynamic light scattering method.

[0186] The aspect ratio of the primary particles of PTFE is preferably less than 2.00, more preferably 1.90 or less, even more preferably 1.80 or less, even more preferably 1.70 or less, especially preferably 1.60 or less, and particularly preferably 1.50 or less. The aspect ratio is more preferably 1.45 or less, even more preferably 1.40 or less, even more preferably 1.35 or less, especially preferably 1.30 or less, especially preferably 1.20 or less, and most preferably 1.10 or less. When measuring in an aqueous dispersion, the aspect ratio is determined by observing an aqueous PTFE dispersion diluted to a solids concentration of approximately 1% by mass with a scanning electron microscope (SEM), processing images of at least 400 randomly selected particles, and averaging the ratio of their major axis to their minor axis. When measuring in powder form, the aspect ratio can be obtained by irradiating PTFE powder with an electron beam, adding it to an aqueous fluorosurfactant solution, and redispersing it using ultrasound to obtain an aqueous PTFE dispersion. The aspect ratio is determined from this PTFE aqueous dispersion by the same method as that used for measuring aqueous dispersions.

[0187] The standard specific gravity (SSG) of PTFE is preferably 2.280 or less, more preferably 2.210 or less, even more preferably 2.200 or less, even more preferably 2.190 or less, and especially preferably 2.180 or less. Preferably, it is 2.130 or more. SSG is measured by the water displacement method according to ASTM D 792 using a sample molded according to ASTM D 4895-89.

[0188] The PTFE preferably has a peak temperature in the range of 333 to 347°C. More preferably, it is 335°C or higher and 345°C or lower. The peak temperature is the temperature corresponding to the maximum value on the heat of fusion curve when PTFE that has not been heated to temperatures above 300°C is heated at a rate of 10°C / min using a differential scanning calorimeter (DSC). The peak temperature can also be identified as the temperature corresponding to the maximum value that appears on a differential thermal (DTA) curve obtained by heating PTFE that has not been heated to temperatures above 300°C at a rate of 10°C / min using a TG / DTA (thermogravimetric / differential thermal analyzer).

[0189] <Polymer (I)> The first coating composition of the present disclosure contains a polymer (I). The second coating composition and the third coating composition of the present disclosure preferably contain a polymer (I). The polymer (I) contains polymerized units (I) based on a monomer represented by general formula (I). The polymer (I) preferably contains two or more polymerized units (I). CX 1 X 3 =CX 2 R(-CZ 1 Z 2 -A 0 ) m (I) (In the formula, X 1 and X 3 are each independently F, Cl, H, or CF; X 2 is H, F, an alkyl group or a fluorine-containing alkyl group; A 0 is an anionic group; R is a linking group; Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or greater. X 2 is preferably F, Cl, H or CF3. 1 and Z 2 is preferably F or CF3.

[0190] In the present disclosure, the anionic group includes functional groups that provide anionic groups such as sulfate groups, carboxylate groups, acid groups such as -COOH, acid salt groups such as -COONH4, etc. Examples of anionic groups include sulfate groups, carboxylate groups, phosphate groups, phosphonate groups, sulfonate groups, or -C(CF3)2OM (wherein M is -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0191] The polymer (I) may contain only polymerized units (I) based on one type of monomer represented by general formula (I), or may contain polymerized units (I) based on two or more types of monomers represented by general formula (I).

[0192] R is a linking group. In the present disclosure, a "linking group" is an (m+1)-valent linking group, and when m is 1, it refers to a divalent linking group. The linking group may be a single bond and preferably contains at least one carbon atom, and the number of carbon atoms may be 2 or more, 4 or more, 8 or more, 10 or more, or 20 or more. There is no upper limit, but it may be, for example, 100 or less, or 50 or less.

[0193] The linking group may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and may optionally contain one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and may optionally contain one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urethane, urea, and carbamate. The linking group may not contain carbon atoms but may be a catenary heteroatom such as oxygen, sulfur, or nitrogen.

[0194] m is an integer of 1 or more, preferably 1 or 2, and more preferably 1. When m is an integer of 2 or more, Z 1 , Z 2 and A 0 may be the same or different. Next, a preferred structure when m is 1 in general formula (I) will be described.

[0195] R is preferably a catenary heteroatom such as oxygen, sulfur, or nitrogen, or a divalent organic group.

[0196] When R is a divalent organic group, the hydrogen atom bonded to the carbon atom may be replaced with a halogen atom other than fluorine, such as chlorine, and may or may not contain a double bond. R may be either linear or branched, and may be cyclic or acyclic. R may also contain a functional group (e.g., ester, ether, ketone (keto group), amine, halide, etc.).

[0197] R may also be a non-fluorinated divalent organic group, or a partially fluorinated or perfluorinated divalent organic group.

[0198] R may be, for example, a hydrocarbon group in which no fluorine atoms are bonded to the carbon atoms, a hydrocarbon group in which some of the hydrogen atoms bonded to the carbon atoms are substituted with fluorine atoms, or a hydrocarbon group in which all of the hydrogen atoms bonded to the carbon atoms are substituted with fluorine atoms, and these may contain an oxygen atom, a double bond, or a functional group.

[0199] R is preferably a hydrocarbon group having 1 to 100 carbon atoms which may contain an ether bond or a keto group, and in the hydrocarbon group, some or all of the hydrogen atoms bonded to the carbon atoms may be substituted with fluorine.

[0200] R is preferably -(CH2) a -, -(CF2) a -, -O-(CF2) a -, -(CF2) a -O-(CF2) b -, -O(CF2) a -O-(CF2) b -, -(CF2) a -[O-(CF2) b ] c -, -O(CF2) a -[O-(CF2) b ] c -, -[(CF2) a -O] b -[(CF2) c -O] d -, -O[(CF2) a-O] b -[(CF2) c -O] d -, -O-[CF2CF(CF3)O] a -(CF2) b -, -[CF2CF(CF3)O] a -, -[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -, -(CF2) a -O-[CF(CF3)CF2O] a -(CF2) b -, -[CF2CF(CF3)] a -CO-(CF2) b - and at least one selected from the combinations thereof. In the formula, a, b, c, and d are independently at least 1. a, b, c, and d may independently be 2 or more, 3 or more, 4 or more, 10 or more, or 20 or more. The upper limit of a, b, c, and d is, for example, 100.

[0201] R is represented by the general formula (r1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g - (r1) (In the formula, X 6 are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, and g is 0 or 1), and a divalent group represented by the general formula (r2): -CF2-O-(CX 7 2) e -(O) g - (r2) (In the formula, X 7 are each independently H, F or CF3, e is an integer of 0 to 3, and g is 0 or 1), and a divalent group represented by the formula:

[0202] Specific examples of suitable R include -CF2-O-, -CF2-O-CF2-, -CF2-O-CH2-, -CF2-O-CH2CF2-, -CF2-O-CF2CF2-, -CF2-O-CF2CH2-, -CF2-O-CF2CF2CH2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, -CF2-O-CF(CF3)CF2-O-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CH2-, and the like. Among these, R is preferably a perfluoroalkylene group which may contain an oxygen atom, specifically, -CF2-O-, -CF2-O-CF2-, -CF2-O-CF2CF2-, -CF2-O-CF(CF3)-, -CF2-O-CF(CF3)CF2-, or -CF2-O-CF(CF3)CF2-O-.

[0203] -R-CZ of general formula (I) 1 Z 2 - is a general formula (s1): -CF2-O-(CX 6 2) e -{O-CF(CF3)} f -(O) g -CZ 1 Z 2 - (s1) (In the formula, X 6 are each independently H, F, or CF3, e is an integer of 0 to 3, f is an integer of 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group), and in formula (s1), Z 1 and Z 2 More preferably, they are F or CF3, and even more preferably, one is F and the other is CF3.

[0204] In addition, in the general formula (I), -R-CZ 1 Z 2 - as the general formula (s2): -CF2-O-(CX 7 2) e -(O) g-CZ 1 Z 2 - (s2) (In the formula, X 7 are each independently H, F, or CF3, e is an integer of 0 to 3, g is 0 or 1, and Z 1 and Z 2 are each independently H, F, an alkyl group or a fluorine-containing alkyl group), and in formula (s2), Z 1 and Z 2 More preferably, they are F or CF3, and even more preferably, one is F and the other is CF3.

[0205] -R-CZ of general formula (I) 1 Z 2 - as -CF2-O-CF2-, -CF2-O-CF(CF3)-, -CF2-OC(CF3)2-, -CF2-O-CF2-CF2-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2-C(CF3)2-, -CF2-O-CF2CF2-CF2-, -CF2-O-CF2CF2- CF(CF3)-, -CF2-O-CF2CF2-C(CF3)2-, -CF2-O-CF(CF3)-CF2-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)-C(CF3)2-, -CF2-O-CF(CF3)CF2-CF2-, -CF2-O-CF(CF3)CF 2-CF(CF3)-, -CF2-O-CF(CF3)CF2-C(CF3)2-, -CF2-O-CF(CF3)CF2-O-CF2-, -CF2-O-CF(CF3)CF2-O-CF(CF3)-, or -CF2-O-CF(CF3)CF2-OC(CF3)2- is preferred, and -CF2-O-CF( CF3)-, -CF2-O-CF2-CF(CF3)-, -CF2-O-CF2CF2-CF(CF3)-, -CF2-O-CF(CF3)-CF(CF3)-, -CF2-O-CF(CF3)CF2-CF(CF3)-, or -CF2-O-CF(CF3)CF2-O-CF(CF3)- is more preferable.

[0206] It is also preferred that the polymer (I) is highly fluorinated. For example, it contains anionic groups (A) such as phosphate moieties (e.g., CH2OP(O)(OM)2) and sulfate moieties (e.g., CH2OS(O)2OM). 0 ), it is preferred that 80% or more, 90% or more, 95% or more, or 100% of the C—H bonds in the polymer (I) are substituted with C—F bonds.

[0207] The polymer (I) contains an anionic group (A 0 ) except for the C—F bond, it is also preferable that the compound has no C—H bond. 1 , X 2 , and X 3 are all F, and R is preferably a perfluoroalkylene group having one or more carbon atoms, and the perfluoroalkylene group may be either linear or branched, may be cyclic or acyclic, and may contain at least one catenary heteroatom. The number of carbon atoms in the perfluoroalkylene group may be 2 to 20, or may be 4 to 18.

[0208] The polymer (I) may be partially fluorinated. That is, the polymer (I) may contain an anionic group (A 0 ), it is also preferred that the alkyl group has at least one hydrogen atom bonded to a carbon atom and at least one fluorine atom bonded to a carbon atom.

[0209] Anionic group (A 0) may be —SO3M, —OSO3M, —COOM, —SONR′CH2COOM, —CH2OP(O)(OM)2, [—CH2O]2P(O)(OM), —CH2CH2OP(O)(OM)2, [—CH2CH2O]2P(O)(OM), —CH2CH2OSO3M, —P(O)(OM)2, —SONR′CH2CH2OP(O)(OM)2, [—SONR′CH2CH2O]2P(O)(OM), —CH2OSO3M, —SONR′CH2CH2OSO3M, or —C(CF3)2OM. Of these, -SO3M, -OSO3M, -COOM, -P(O)(OM)2 or -C(CF3)2OM is preferred, -COOM, -SO3M, -OSO3M or -C(CF3)2OM is more preferred, -SO3M, -COOM or -P(O)(OM)2 is even more preferred, -SO3M or -COOM is particularly preferred, and -COOM is most preferred.

[0210] M is H, metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0211] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K or Li is preferred.

[0212] M is -H, a metal atom, or NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 7 4 is more preferred, -H, -Na, -K, -Li or NH4 is even more preferred, -H, -Na, -K or NH4 is even more preferred, -H, -Na or NH4 is especially preferred, and -H or -NH4 is most preferred.

[0213] In the polymer (I), each polymer unit (I) may have a different anionic group or may have the same anionic group.

[0214] The polymer (I) is also preferably a polymer containing polymerized units (Ia) based on a monomer represented by general formula (Ia). CF2=CF-O-Rf 0 -A 0 (Ia) (In the formula, A 0 is an anionic group, and Rf 0 is a perfluorinated divalent linking group which may be linear or branched, cyclic or acyclic in structure, saturated or unsaturated, substituted or unsubstituted, and which optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen.

[0215] The polymer (I) is also preferably a polymer containing polymerized units (Ib) based on a monomer represented by general formula (Ib). CH2=CH-O-Rf 0 -A 0 (Ib) (In the formula, A 0 is an anionic group, and Rf 0 is a perfluorinated divalent linking group defined by formula Ia.

[0216] In general formula (I), A 0 is a sulfate group. 0 is, for example, -CH2OSO3M, -CH2CH2OSO3M, or -SO2NR'CH2CH2OSO3M, where R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0217] A 0is a sulfate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(O(CF2)4CH2OSO3M), CF2=CF(OCF2CF(CF3)CH2OSO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OSO3M), CH2=CH((CF2)4CH2OSO3M), CF2=CF(OCF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), CF2=CF(OCF2CF2CF2CF2SON(CH3)CH2CH2OSO3M), CH2=CH(CF2CF2CH2OSO3M), and the like. In the above formula, M is the same as above.

[0218] In general formula (I), A 0 In one preferred embodiment, A is a sulfonate group. 0 An example of such a group is -SO3M, where M is the same as above.

[0219] A 0 is a sulfonate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2SO3M), CF2=CF(O(CF2)3SO3M), CF2=CF(O(CF2)4SO3M), CF2=CF(OCF2CF(CF3)SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2SO3M), CH2=CH(CF2CF2SO3M), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO3M), CH2=CH(CF2CF2SO3M), CH2=CH(CF2CF2SO3M), CH2=CH(CF2CF2SO3M), CH2=CH((CF2)4SO3M), CH2=CH(CF2CF2SO3M), CH2=CH((CF2)3SO3M), etc. In the above formulas, M is the same as above.

[0220] In general formula (I), A 0 A is preferably a carboxylate group. 0 Examples of A include -COOM or -SO2NR'CH2COOM, where R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.0 is a carboxylate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2COOM), CF2=CF(O(CF2)3COOM), CF2=CF(O(CF2)4COOM), CF2=CF(O(CF2)5COOM), CF2=CF(OCF2CF(CF3)COOM), CF2=CF(OCF2CF(CF3)O(CF2) n COOM) (n is greater than 1), CH2=CH(CF2CF2COOM), CH2=CH((CF2)4COOM), CH2=CH((CF2)3COOM), CF2=CF(OCF2CF2SO2NR'CH2COOM), CF2=CF(O(CF2)4SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2SO2NR'CH2COOM), CH2=CH(CF2CF2SO2NR'CH2COOM), CF2=CF(OCF2CF(CF3)OCF2CF2CF2CF2SO2NR'CH2COOM), CH2=CH((CF2)4SO2NR'CH2COOM), CH2=CH((CF2)3SO2NR'CH2COOM). In the above formula, R' is H or an alkyl group having 1 to 4 carbon atoms, and M is the same as above.

[0221] In general formula (I), A 0 In one preferred embodiment, A is a phosphate group. 0 Examples of the alkyl group include -CH2OP(O)(OM)2, [-CH2O]2P(O)(OM), -CH2CH2OP(O)(OM)2, [-CH2CH2O]2P(O)(OM), [-SON2NR'CH2CH2O]2P(O)(OM) and -SON2NR'CH2CH2OP(O)(OM), where R' is an alkyl group having 1 to 4 carbon atoms and M is the same as above.

[0222] A 0is a phosphate, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2CH2OP(O)(OM)2), CF2=CF(O(CF2)4CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)CH2OP(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2CH2OP(O)(OM)2), CF2=CF(O Examples include CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CF2=CF(OCF2CF2CF2CF2SO2N(CH3)CH2CH2OP(O)(OM)2), CH2=CH(CF2CF2CH2OP(O)(OM)2), CH2=CH((CF2)4CH2OP(O)(OM)2), CH2=CH((CF2)3CH2OP(O)(OM)2), etc. In the above formula, M is the same as above.

[0223] In general formula (I), A 0 In one preferred embodiment, A is a phosphonate group. 0 is a phosphonate group, examples of the monomer represented by general formula (I) include CF2=CF(OCF2CF2P(O)(OM)2), CF2=CF(O(CF2)4P(O)(OM)2), CF2=CF(OCF2CF(CF3)P(O)(OM)2), CF2=CF(OCF2CF(CF3)OCF2CF2P(O)(OM)2), CH2=CH(CF2CF2P(O)(OM)2), CH2=CH((CF2)4P(O)(OM)2), CH2=CH((CF2)3P(O)(OM)2), where M is the same as above.

[0224] The polymer (I) is preferably a polymer (1) containing polymerized units (1) based on a monomer represented by general formula (1). CX2=CY(-CZ2-O-Rf-A) (1) (In the formula, X's are the same or different and are -H or -F; Y's are -H, -F, an alkyl group or a fluorine-containing alkyl group; Z's are the same or different and are -H, -F, an alkyl group or a fluoroalkyl group; Rf's are fluorine-containing alkylene groups having 1 to 40 carbon atoms or fluorine-containing alkylene groups having 2 to 100 carbon atoms and an ether bond; A's are -COOM, -SO3M, -OSO3M or -C(CF3)2OM (M's are -H, a metal atom, -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.) However, at least one of X, Y and Z contains a fluorine atom.) The fluorine-containing alkylene group having an ether bond and having 2 to 100 carbon atoms is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and contains an ether bond between carbon atoms. The coating composition of the present disclosure contains polymer (1), which improves the ability to inhibit aggregation during stirring of the coating composition. The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0225] In general formula (1), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0226] In general formula (1), Y is -H, -F, an alkyl group or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F or -CF3, and more preferably -F.

[0227] In general formula (1), Z's may be the same or different and represent -H, -F, an alkyl group, or a fluoroalkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Z's are preferably -H, -F, or -CF3, and more preferably -F.

[0228] In general formula (1), at least one of X, Y, and Z contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0229] In the general formula (1), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond.

[0230] The number of carbon atoms in the fluorine-containing alkylene group is preferably 2 or more. The number of carbon atoms in the fluorine-containing alkylene group is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, and -CF(CF3)CH2-. The fluorine-containing alkylene group is preferably a perfluoroalkylene group.

[0231] The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, and even more preferably 12 or less. The fluorine-containing alkylene group having an ether bond is, for example, a group represented by the general formula: [ka] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is also preferably a divalent group represented by the formula: H, F, or CF3; p1+q1+r1 is an integer of 1 to 10; s1 is 0 or 1; and t1 is an integer of 0 to 5).

[0232] Specific examples of the fluorine-containing alkylene group having an ether bond include -CF2CF(CF3)OCF2CF2-, -CF(CF3)CF2-O-CF(CF3)-, -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer of 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n Examples include -CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0233] In the general formula (1), A is -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (M is -H, a metal atom, or -NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group).

[0234] R 7 As for H or C 1-10 is preferably an organic group represented by the formula: 1-4 The organic group is more preferably H or C 1-4 More preferred are alkyl groups of the formula:

[0235] Examples of the metal atom include alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K or Li is preferred.

[0236] M is —H, a metal atom, or —NR 7 4 is preferred, and -H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or -NR 7 4 is more preferred, -H, -Na, -K, -Li or -NH4 is even more preferred, -Na, -K or -NH4 is even more preferred, -Na or -NH4 is especially preferred, and -NH4 is most preferred.

[0237] A is preferably -COOM or -SO3M, and more preferably -COOM.

[0238] Examples of the monomer represented by general formula (1) include a monomer represented by general formula (1a): CX2=CFCF2-O-(CF(CF3)CF2O) n5 -CF(CF3)-A (1a) (wherein each X is the same and represents F or H, n5 represents 0 or an integer of 1 to 10, and A is as defined above) is an example.

[0239] In general formula (1a), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, in that PTFE particles having a small primary particle size can be obtained.

[0240] The polymer (1) may be a homopolymer of the monomer represented by the general formula (1a) or a copolymer with other monomers.

[0241] The polymerized unit (1) is preferably a polymerized unit (1A) based on a monomer represented by general formula (1A). CH2=CF(-CF2-O-Rf-A) (1A) (wherein Rf and A are the same as above.)

[0242] The polymer (1) may be a homopolymer of the monomer represented by the general formula (1A) or a copolymer with other monomers.

[0243] Specific examples of the monomer represented by formula (1A) include the monomer represented by the general formula:

[0244] [ka]

[0245] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4 is H, F, or CF3; p1+q1+r1 are integers from 0 to 10; s1 is 0 or 1; t1 is an integer from 0 to 5, except for Z 3 and Z 4 are both H, then p1+q1+r1+s1 is not 0; A is the same as defined above). More specifically,

[0246] [ka]

[0247] Among them,

[0248] [ka]

[0249] It is preferable that:

[0250] As the monomer represented by general formula (1A), it is preferable that A in formula (1A) is -COOM, and in particular, at least one selected from the group consisting of CH2=CFCF2OCF(CF3)COOM and CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (wherein M is as defined above) is preferred, with CH2=CFCF2OCF(CF3)COOM being more preferred.

[0251] Further, examples of the monomer represented by the general formula (1) include the monomer represented by the following formula: CF2=CFCF2-O-Rf-A (wherein Rf and A are the same as above)

[0252] More specifically, [ka] etc.

[0253] The polymer (I) is also preferably a polymer (2) containing polymerized units (2) based on a monomer represented by general formula (2). CX2=CY(-O-Rf-A) (2) (In the formula, X's are the same or different and represent -H or -F; Y represents -H, -F, an alkyl group or a fluorine-containing alkyl group; Rf represents a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and having an ether bond or a keto group; and A is the same as defined above.)

[0254] In general formula (2), X is -H or -F. Both Xs may be -F, or at least one X may be -H. For example, one X may be -F and the other may be -H, or both Xs may be -H.

[0255] In general formula (2), Y is -H, -F, an alkyl group, or a fluorine-containing alkyl group. The alkyl group is an alkyl group that does not contain a fluorine atom, and may have one or more carbon atoms. The alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. The fluorine-containing alkyl group is an alkyl group that contains at least one fluorine atom, and may have one or more carbon atoms. The fluorine-containing alkyl group preferably has six or fewer carbon atoms, more preferably four or fewer carbon atoms, and even more preferably three or fewer carbon atoms. Y is preferably -H, -F, or -CF3, and more preferably -F.

[0256] In general formula (2), it is preferable that at least one of X and Y contains a fluorine atom. For example, X may be —H, and Y and Z may be —F.

[0257] In general formula (2), Rf is a fluorine-containing alkylene group having 1 to 40 carbon atoms, a fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms, or a fluorine-containing alkylene group having a keto group having 2 to 100 carbon atoms. The fluorine-containing alkylene group having an ether bond having 2 to 100 carbon atoms is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0258] The number of carbon atoms in the fluorine-containing alkylene group of Rf is preferably 2 or more. Also, it is preferably 30 or less, more preferably 20 or less, even more preferably 10 or less, and particularly preferably 5 or less. Examples of the fluorine-containing alkylene group include -CF2-, -CH2CF2-, -CF2CF2-, -CF2CH2-, -CF2CF2CH2-, -CF(CF3)-, -CF(CF3)CF2-, -CF(CF3)CH2-, -CF2CF2CF2-, CF2CF2CF2CF2-, and the like. The fluorine-containing alkylene group is preferably a perfluoroalkylene group, and more preferably an unbranched linear perfluoroalkylene group.

[0259] The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 3 or more. The number of carbon atoms in the fluorine-containing alkylene group having an ether bond is preferably 60 or less, more preferably 30 or less, even more preferably 12 or less, and particularly preferably 5 or less. The fluorine-containing alkylene group having an ether bond is, for example, a group represented by the general formula: [ka] (In the formula, Z 1 is F or CF3;Z 2 and Z 3 are H or F;Z respectively 4is also preferably a divalent group represented by the formula: H, F, or CF3; p1+q1+r1 is an integer of 1 to 10; s1 is 0 or 1; and t1 is an integer of 0 to 5).

[0260] Specific examples of the fluorine-containing alkylene group having an ether bond include -CF2CF(CF3)OCF2CF2-, -CF2CF(CF3)OCF2CF2-, -CF2CF(CF3)OCF2CF2CF2-, -CF(CF3)CF2-O-CF(CF3)-, -(CF(CF3)CF2-O) n -CF(CF3)- (wherein n is an integer of 1 to 10), -CF(CF3)CF2-O-CF(CF3)CH2-, -(CF(CF3)CF2-O) n Examples include -CF(CF3)CH2- (wherein n is an integer of 1 to 10), -CH2CF2CF2O-CH2CF2CH2-, -CF2CF2CF2O-CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2-, -CF2CF2CF2O-CF2CF2CH2-, -CF2CF2O-CF2-, -CF2CF2O-CF2CH2-, etc. The fluorine-containing alkylene group having an ether bond is preferably a perfluoroalkylene group.

[0261] The carbon number of the fluorine-containing alkylene group having a keto group is preferably 3 or more. The carbon number of the fluorine-containing alkylene group having a keto group is preferably 60 or less, more preferably 30 or less, even more preferably 12 or less, and particularly preferably 5 or less.

[0262] Specific examples of the fluorine-containing alkylene group having a keto group include -CF2CF(CF3)CO-CF2-, -CF2CF(CF3)CO-CF2CF2-, -CF2CF(CF3)CO-CF2CF2CF2-, -CF2CF(CF3)CO-CF2CF2CF2-, etc. The fluorine-containing alkylene group having a keto group is preferably a perfluoroalkylene group.

[0263] Water may be added to the keto group in the fluorine-containing alkylene group. Therefore, the monomer (2) may be a hydrate. Examples of the fluorine-containing alkylene group in which water is added to the keto group include -CFCF(CF)C(OH)-CF-, -CFCF(CF)C(OH)-CFCF-, -CFCF(CF)C(OH)-CFCFCF-, and -CFCF(CF)C(OH)-CFCFCFCF-.

[0264] The monomer represented by general formula (2) is preferably at least one selected from the group consisting of monomers represented by general formulas (2a), (2b), (2c), (2d), (2e), (2f) and (2g). CF2=CF-O-(CF2) n1 -A (2a) (wherein n1 represents an integer of 1 to 10, and A is the same as defined above.) CF2=CF-O-(CF2C(CF3)F) n2 -A (2b) (wherein n2 represents an integer of 1 to 5, and A is as defined above.) CF2=CF-O-(CFX 1 ) n3 -A (2c) (In the formula, X 1 represents F or CF3, n3 represents an integer of 1 to 10, and A is as defined above. CF2=CF-O-(CF2CFX 1 O) n4 -(CF2) n6 -A (2d) (wherein n4 represents an integer of 1 to 10, n6 represents an integer of 1 to 3, and A and X 1 is the same as the definition above.) CF2=CF-O-(CF2CF2CFX 1 O) n5 -CF2CF2CF2-A (2e) (wherein n5 represents an integer of 0 to 10, and A and X 1 is the same as the definition above.) CF2=CF-O-(CF2) n7 -O-(CF2) n8 -A (2f) (In the formula, n7 represents an integer of 1 to 10, n8 represents an integer of 1 to 3, and A is as defined above.) CF2=CF[OCF2CF(CF3)] n9 O(CF2) n10 O[CF(CF3)CF2O] n11 CF(CF3)-A (2g) (In the formula, n9 represents an integer of 0 to 5, n10 represents an integer of 1 to 8, and n11 represents an integer of 0 to 5. A is as defined above.)

[0265] In the general formula (2a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less.

[0266] Examples of the monomer represented by general formula (2a) include CF2=CF-O-CF2COOM, CF2=CF(OCF2CF2COOM), CF2=CF(O(CF2)3COOM), CF2=CF(OCF2CF2SO3M), CF2=CFOCF2SO3M, and CF2=CFOCF2CF2CF2SO3M (wherein M is as defined above).

[0267] In general formula (2b), n2 is preferably an integer of 3 or less, from the viewpoint of inhibiting aggregation during stirring of the resulting coating composition.

[0268] In general formula (2c), n3 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H, Na, or NH4.

[0269] In general formula (2d), X 1 is preferably -CF3 from the viewpoint of aggregation suppression during stirring of the coating composition, n4 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H, Na or NH4.

[0270] Examples of the monomer represented by general formula (2d) include CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2CF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2SO3M, CF2=CFOCF2CF(CF3)OCF2CF2CF2SO3M (wherein M represents H, NH4, or an alkali metal).

[0271] In general formula (2e), n5 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM, and M is preferably H or NH4.

[0272] Examples of the monomer represented by general formula (2e) include CF2=CFOCF2CF2CF2COOM (wherein M represents H, Na, NH4 or an alkali metal).

[0273] In general formula (2f), n7 is preferably an integer of 5 or less from the viewpoint of water solubility, A is preferably -COOM or -SO3M, and more preferably -COOM, and M is preferably H, Na, K, or NH4.

[0274] Examples of the monomer represented by general formula (2f) include CF2=CF-O-(CF2)3-O-CF2-COOM (wherein M represents H, NH4 or an alkali metal).

[0275] In general formula (2g), n9 is preferably an integer of 3 or less from the viewpoint of water solubility, n10 is preferably an integer of 3 or less, n11 is preferably an integer of 3 or less, A is preferably -COOM or -SO3M, and more preferably -COOM. M is preferably H, Na, K, or NH4.

[0276] Examples of the monomer represented by general formula (2g) include CF2=CFO(CF2)2OCF(CF3)COOM, CF2=CFOCF2CF2OCF(CF3)CF2OCF(CF3)COOM, CF2=CFOCF2CF(CF3)OCF2CF2OCF(CF3)COOM, CF2=CF[OCF2CF(CF3)]2O(CF2)2O[CF(CF3)CF2O]CF(CF3)COOM, and CF2=CF[OCF2CF(CF3)]3O(CF2)2O[CF(CF3)CF2O]3CF(CF3)COOM (wherein M represents H, NH4, or an alkali metal).

[0277] The polymer (I) is also preferably a polymer (3) containing polymerized units (3) based on a monomer represented by general formula (3). CX2=CY(-Rf-A) (3) (In the formula, X's are the same or different and represent -H or -F; Y represents -H, -F, an alkyl group or a fluorine-containing alkyl group; Rf represents a fluorine-containing alkylene group having 1 to 40 carbon atoms or a fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond; and A is the same as defined above.)

[0278] The fluorine-containing alkylene group having 2 to 100 carbon atoms and an ether bond is an alkylene group that does not contain a structure in which an oxygen atom is at the terminal and that contains an ether bond between carbon atoms.

[0279] In general formula (3), Rf is preferably a fluorine-containing alkylene group having a carbon number of 1 to 40. In general formula (3), at least one of X and Y preferably contains a fluorine atom.

[0280] The monomer represented by general formula (3) is represented by general formula (3a): CF2=CF-(CF2) n1 -A (3a) (wherein n1 represents an integer of 1 to 10, and A is as defined above), and a monomer represented by general formula (3b): CF2=CF-(CF2C(CF3)F) n2 -A (3b) (wherein n2 represents an integer of 1 to 5, and A is as defined above), is preferred.

[0281] In the general formula (3a) and the general formula (3b), A is preferably -SO3M or -COOM, and M is preferably H, a metal atom, or NR 7 4. It is preferably an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 7 represents H or an organic group.

[0282] In general formula (3a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. A is preferably -COOM, and M is preferably H or NH4.

[0283] An example of the monomer represented by general formula (3a) is CF2=CFCF2COOM (wherein M is as defined above).

[0284] In general formula (3b), n2 is preferably an integer of 3 or less from the viewpoint of inhibiting aggregation during stirring of the resulting coating composition, A is preferably -COOM, and M is preferably H or NH4.

[0285] Next, a preferred configuration when m in general formula (I) is an integer of 2 or more will be described.

[0286] It is also preferable that the polymer (I) is a polymer (4) containing polymerization units (4) based on at least one monomer selected from the group consisting of monomers represented by general formula (4a) and general formula (4b). CF2=CF-CF2-OQ F1 -CF(-Q F2 -CZ 1 Z 2 -A)2(4a) (In the formula, Z 1 , Z 2and A are the same as above, Q F1 and Q F2 are the same or different and are a single bond, a fluorine-containing alkylene group which may contain an ether bond between carbon atoms, or a fluorine-containing oxyalkylene group which may contain an ether bond between carbon atoms. CF2=CF-OQ F1 -CF(-Q F2 -CZ 1 Z 2 -A)2(4b) (In the formula, Z 1 , Z 2 , A, Q F1 and Q F2 is the same as above)

[0287] The monomers represented by general formula (4a) and general formula (4b) include: [ka] etc.

[0288] The polymer (I) is preferably at least one selected from the group consisting of the polymer (1), the polymer (2) and the polymer (3), and more preferably the polymer (1).

[0289] The polymer (I) may be a homopolymer consisting of only the polymerized unit (I), or may be a copolymer containing the polymerized unit (I) and a polymerized unit based on another monomer copolymerizable with the monomer represented by general formula (I). From the viewpoint of solubility in an aqueous medium, a homopolymer consisting of only the polymerized unit (I) is preferred. The polymerized units (I) may be the same or different in each occurrence, and the polymer (I) may contain polymerized units (I) based on two or more different monomers represented by general formula (I).

[0290] The other monomer is preferably a monomer represented by the general formula CFR=CR2 (wherein R is independently H, F, or a perfluoroalkyl group having 1 to 4 carbon atoms). Fluorine-containing ethylenic monomers having 2 or 3 carbon atoms are also preferred. Examples of the other monomer include CF2=CF2, CF2=CFCl, CH2=CF2, CFH=CH2, CFH=CF2, CF2=CFCF3, CH2=CFCF3, CH2=CHCF3, CHF=CHCF3 (E-form), and CHF=CHCF3 (Z-form). Among these, at least one selected from the group consisting of tetrafluoroethylene (CF2=CF2), chlorotrifluoroethylene (CF2=CFCl) and vinylidene fluoride (CH2=CF2) is preferred in terms of good copolymerizability, and at least one selected from the group consisting of tetrafluoroethylene and vinylidene fluoride is more preferred. Therefore, the polymerized units based on the other monomer are preferably polymerized units based on tetrafluoroethylene. The polymerized units based on the other monomers may be the same or different in each occurrence, and the polymer (I) may contain polymerized units based on two or more different other monomers.

[0291] The other monomers also include those represented by the general formula (n1-2):

[0292] [ka]

[0293] (In the formula, X 1 , X 2 are the same or different H or F;X 3 is H, F, Cl, CH3 or CF3; X 4 , X 5 are the same or different and are H or F; a and c are the same or different and are 0 or 1. Rf 3 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond).

[0294] Specifically, CH2=CFCF2-O-Rf 3 , CF2=CF-O-Rf 3 , CF2=CFCF2-O-Rf 3 , CF2=CF-Rf 3 , CH2=CH-Rf 3 , CH2=CH-O-Rf 3 (In the formula, Rf 3 is the same as the above formula (n1-2)).

[0295] Examples of the other monomers include those of formula (n2-1):

[0296] [ka]

[0297] (In the formula, X 9 is H, F or CH3; Rf 4 Also included are fluorine-containing acrylate monomers represented by Rf (a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and an ether bond). 4 The base is

[0298] [ka]

[0299] (wherein d3 is an integer of 1 to 4; e3 is an integer of 1 to 10).

[0300] Examples of the other monomers include those of formula (n2-2): CH2=CHO-Rf 5 (n2-2) (In the formula, Rf 5 Also included are fluorine-containing vinyl ethers represented by the formula (wherein the alkyl group is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond).

[0301] Specific examples of the monomer of general formula (n2-2) include:

[0302] [ka]

[0303] (wherein e6 is an integer of 1 to 10) are preferred.

[0304] More specifically,

[0305] [ka]

[0306] Examples include:

[0307] Others include those of general formula (n2-3): CH2=CHCH2O-Rf 6 (n2-3) (In the formula, Rf 6 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond), a fluorine-containing allyl ether represented by the general formula (n2-4): CH2=CH-Rf 7 (n2-4) (In the formula, Rf 7 is a fluorine-containing alkyl group having 1 to 40 carbon atoms or a fluorine-containing alkyl group having 2 to 100 carbon atoms and having an ether bond), and the like.

[0308] Specific examples of the monomers represented by general formulas (n2-3) and (n2-4) include:

[0309] [ka]

[0310] Examples of such monomers include:

[0311] The polymer (I) usually has a terminal group. The terminal group is a terminal group generated during polymerization, and typical terminal groups are independently selected from hydrogen, iodine, bromine, linear or branched alkyl groups, and linear or branched fluoroalkyl groups, and may optionally contain at least one catenary heteroatom. The alkyl group or fluoroalkyl group preferably has 1 to 20 carbon atoms. These terminal groups are generally generated from the initiator or chain transfer agent used to form the polymer (I) or during the chain transfer reaction.

[0312] In the polymer (I), the content of the polymerized units (I) relative to all polymerized units is, in order of preference, 1.0 mol% or more, 3.0 mol% or more, 5.0 mol% or more, 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, and 90 mol% or more. The content of the polymerized units (I) is particularly preferably substantially 100 mol%, and the polymer (I) is most preferably composed only of the polymerized units (I).

[0313] In polymer (I), the content of polymerized units based on other monomers copolymerizable with the monomer represented by general formula (I) is, in order of preference, 99.0 mol% or less, 97.0 mol% or less, 95.0 mol% or less, 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, and 10 mol% or less, based on all polymerized units. It is particularly preferred that the content of polymerized units based on other monomers copolymerizable with the monomer represented by general formula (I) is substantially 0 mol%, and it is most preferred that polymer (I) does not contain polymerized units based on other monomers.

[0314] The number average molecular weight of the polymer (I) is 0.1 × 10 4 More than 0.2 × 10 is preferable. 4 More preferably, 0.3 × 10 4 More preferably, 0.4×10 4 More preferably, 0.5×10 4More than 1.0 × 10 4 More than 3.0 × 10 is particularly preferable. 4 The above is particularly preferable, and 3.1 × 10 4 More than 75.0×10 4 The following is preferable: 50.0 x 10 4 Less than 40.0 x 10 is more preferable. 4 More preferably, 30.0 x 10 4 The following is particularly preferred: 20.0 × 10 4 The following are particularly preferred. The number average molecular weight and weight average molecular weight are values ​​calculated by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard. When measurement by GPC is not possible, the number average molecular weight of polymer (I) can be determined from the correlation between the number average molecular weight calculated from the number of terminal groups obtained by NMR, FT-IR, etc. and the melt flow rate. The melt flow rate can be measured in accordance with JIS K 7210.

[0315] The lower limit of the weight average molecular weight of the polymer (I) is, in order of preference, 0.2×10 4 That's 0.4 x 10 4 More than 0.6 × 10 4 That's 0.8 x 10 4 That's it, 1.0 x 10 4 That's it, 2.0 x 10 4 That's it, 5.0 x 10 4 That's it, 10.0 x 10 4 That's it, 15.0 x 10 4 That's it, 20.0 x 10 4 That's it, 25.0 x 10 4 The upper limit of the weight average molecular weight of the polymer (I) is, in order of preference, 150.0×10 4 Below, 100.0 x 10 4 Below, 60.0 x 10 4 Below, 50.0 x 10 4 Below, 40.0 x 10 4 The following is the result.

[0316] The polymer (I) preferably has an ion exchange ratio (IXR) of 53 or less, where IXR is defined as the number of carbon atoms in the polymer backbone relative to the ionic group. Precursor groups that become ionic upon hydrolysis (e.g., -SOF) are not considered ionic groups for purposes of determining IXR.

[0317] IXR is preferably 0.5 or more, more preferably 1 or more, even more preferably 3 or more, even more preferably 4 or more, particularly preferably 5 or more, and particularly preferably 8 or more. IXR is more preferably 43 or less, more preferably 33 or less, and particularly preferably 23 or less.

[0318] The ion exchange capacity of the polymer (I) is, in order of preference, 0.80 meg / g or more, 1.50 meg / g or more, 1.75 meg / g or more, 2.00 meg / g or more, 2.20 meq / g or more, more than 2.20 meq / g, 2.50 meg / g or more, 2.60 meg / g or more, 3.00 meg / g or more, and 3.50 meg / g or more. The ion exchange capacity is the content of ionic groups (anionic groups) in the polymer (I) and can be calculated from the composition of the polymer (I).

[0319] In polymer (I), the ionic (anionic) groups are typically distributed along the polymer backbone. The polymer (I) comprises a polymer backbone with recurring side chains attached to the backbone, which preferably carry ionic groups.

[0320] Preferably, polymer (I) comprises ionic groups having a pKa of less than 10, more preferably less than 7. The ionic groups of polymer (I) are preferably selected from the group consisting of sulfonate, carboxylate, phosphonate, and phosphate.

[0321] The terms "sulfonate, carboxylate, phosphonate, and phosphate" are intended to refer to the respective salts or the respective acids capable of forming salts. When salts are used, preferably the salts are alkali metal or ammonium salts. A preferred ionic group is a sulfonate group.

[0322] The polymer (I) is preferably water-soluble. Water-soluble means the property of being easily dissolved or dispersed in an aqueous medium. The particle size of the water-soluble polymer (I) cannot be measured by dynamic light scattering (DLS), for example, or the particle size is 10 nm or less.

[0323] The viscosity of an aqueous solution of polymer (I) is preferably 5.0 mPa s or more, more preferably 8.0 mPa s or more, even more preferably 10.0 mPa s or more, particularly preferably 12.0 mPa s or more, and most preferably 14.0 mPa s or more, and preferably 100.0 mPa s or less, more preferably 50.0 mPa s or less, even more preferably 25.0 mPa s or less, and especially preferably 20.0 mPa s or less.

[0324] The viscosity of an aqueous solution of polymer (I) can be determined by adjusting the content of polymer (I) in the aqueous solution to 33 mass % based on the amount of the aqueous solution, and measuring the viscosity of the resulting aqueous solution at 20°C using a tuning fork vibro viscometer (model number: SV-10) manufactured by A&D Corporation.

[0325] The critical micelle concentration (CMC) of the polymer (I) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less.

[0326] The critical micelle concentration of the polymer (I) can be determined by measuring the surface tension, for example, using a surface tensiometer CBVP-A3 manufactured by Kyowa Interface Science Co., Ltd.

[0327] The acid value of the polymer (I) is preferably 60 or more, more preferably 90 or more, even more preferably 120 or more, particularly preferably 150 or more, and most preferably 180 or more. The upper limit is not particularly limited, but is preferably 300 or less.

[0328] The acid value of the polymer (I) is determined by the presence of an anionic group other than an acid functional group, such as -COOM, -SO3M, -OSO3M, or -C(CF3)2OM (where M is a metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 If the compound has a hydroxyl group (H or an organic group), these groups can be converted to acid forms and then measured by acid-base titration.

[0329] The polymer (I) can be produced by a conventionally known method except for using the above-mentioned monomers.

[0330] In the first coating composition of the present disclosure, the content of polymer (I) is 2000 ppm by mass or less relative to the coating composition. The content of polymer (I) in the first coating composition of the present disclosure is preferably 1500 ppm by mass or less, and may also be 1000 ppm by mass or less, 500 ppm by mass or less, or 250 ppm by mass or less. Furthermore, the content of polymer (I) in the first coating composition of the present disclosure is preferably 0.1 ppm by mass or more, and more preferably 0.5 ppm by mass or more relative to the coating composition.

[0331] In the first coating composition of the present disclosure, the content of polymer (I) relative to the fluororesin is preferably 0.1 ppm by mass or more, more preferably 0.2 ppm by mass or more, even more preferably 0.5 ppm by mass or more, particularly preferably 1.0 ppm by mass or more, and most preferably 3.0 ppm by mass or more. The content of polymer (I) relative to the fluororesin may be, for example, 500 ppm by mass or more. Furthermore, in the first coating composition of the present disclosure, the content of polymer (I) relative to the fluororesin is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and may be 0.5% by mass or less, 0.4% by mass or less, or 0.3% by mass or less.

[0332] In the second and third coating compositions of the present disclosure, the content of polymer (I) is preferably 2000 ppm by mass or less, more preferably 1500 ppm by mass or less, and may be 1000 ppm by mass or less, 500 ppm by mass or less, or 250 ppm by mass or less, relative to the coating composition. Furthermore, the content of polymer (I) in the second and third coating compositions of the present disclosure is preferably 0.1 ppm by mass or more, more preferably 0.5 ppm by mass or more, relative to the coating composition.

[0333] In the second and third coating compositions of the present disclosure, the content of polymer (I) in the coating composition is preferably 0.1 ppm by mass or more, more preferably 0.2 ppm by mass or more, even more preferably 0.5 ppm by mass or more, particularly preferably 1.0 ppm by mass or more, and most preferably 3.0 ppm by mass or more, relative to PTFE. The content of polymer (I) may be, for example, 500 ppm by mass or more, relative to PTFE. Furthermore, in the second and third coating compositions of the present disclosure, the content of polymer (I) is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and may be 0.5% by mass or less, 0.4% by mass or less, or 0.3% by mass or less, relative to PTFE.

[0334] The content of polymer (I) in the coating composition of the present disclosure can be determined by solid-state NMR measurement. Also, the content of polymer (I) in the coating composition of the present disclosure can be determined by solid-state NMR measurement, as described in International Publication Nos. 2014 / 099453, 2010 / 075497, 2010 / 075496, 2011 / 008381, 2009 / 055521, 1987 / 007619, JP-A-61-293476, 2010 / 075494, 2010 / 075359, 2012 / 082454, 2006 / 119224, 2013 / 085864, JP-A-2014-293476, and the like. Measurement methods for each polymer are described in Publication No. 2012 / 082707, International Publication No. 2012 / 082703, International Publication No. 2012 / 082451, International Publication No. 2006 / 135825, International Publication No. 2004 / 067588, International Publication No. 2009 / 068528, JP 2004-075978, JP 2001-226436, International Publication No. 1992 / 017635, International Publication No. 2014 / 069165, JP 11-181009, etc. As a method for measuring the content of polymer (I), the measurement methods for each polymer described therein can be used.

[0335] The content of dimers and trimers of the monomer represented by general formula (I) in the coating composition of the present disclosure is preferably 1.0 mass% or less, more preferably 0.1 mass% or less, even more preferably 0.01 mass% or less, particularly preferably 0.001 mass% or less, and most preferably 0.0001 mass% or less, relative to polymer (I).

[0336] The content of dimers and trimers of the monomer represented by general formula (I) in the coating composition of the present disclosure can be measured by the same method as for the content of dimers and trimers in polymer (I) described below.

[0337] <Aqueous medium> An aqueous medium refers to a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as an alcohol, ether, or ketone, and / or a fluorine-containing organic solvent having a boiling point of 40°C or lower. The aqueous medium is preferably a mixture of water and an organic solvent. The water content in the coating composition of the present disclosure is preferably 20.0% by mass to 60.0% by mass. Furthermore, from the viewpoint of improving the dispersion stability of a coating composition having a high solids concentration, the water content in the coating composition of the present disclosure may be 40.0% by mass to 50.0% by mass.

[0338] <Nonionic surfactants> The third coating composition of the present disclosure contains a nonionic surfactant. The first coating composition and the second coating composition of the present disclosure preferably contain a nonionic surfactant.

[0339] The nonionic surfactants described above typically contain no charged groups and have a hydrophobic portion that is a long hydrocarbon chain. The hydrophilic portion of the nonionic surfactant contains a water-soluble functional group, such as an ethylene ether chain derived from polymerization with ethylene oxide.

[0340] Examples of nonionic surfactants include the following: Polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters, glycerol esters, and derivatives thereof.

[0341] Specific examples of polyoxyethylene alkyl ethers include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene behenyl ether.

[0342] Specific examples of polyoxyethylene alkylphenyl ethers include polyoxyethylene nonylphenyl ether and polyoxyethylene octylphenyl ether.

[0343] Specific examples of polyoxyethylene alkyl esters include polyethylene glycol monolaurate, polyethylene glycol monooleate, and polyethylene glycol monostearate.

[0344] Specific examples of sorbitan alkyl esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monooleate.

[0345] Specific examples of polyoxyethylene sorbitan alkyl esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, and polyoxyethylene sorbitan monostearate.

[0346] Specific examples of glycerol esters include glycerol monomyristate, glycerol monostearate, and glycerol monooleate.

[0347] Specific examples of the above derivatives include polyoxyethylene alkylamines, polyoxyethylene alkylphenyl-formaldehyde condensates, polyoxyethylene alkyl ether phosphates, and the like.

[0348] The ethers and esters may have an HLB value of 10-18.

[0349] Examples of nonionic surfactants include the Triton (registered trademark) X series (X15, X45, X100, etc.), the Tergitol (registered trademark) 15-S series, the Tergitol (registered trademark) TMN series (TMN-6, TMN-10, TMN-100, etc.), and the Tergitol (registered trademark) L series, all manufactured by The Dow Chemical Company; the Pluronic (registered trademark) R series (31R1, 17R2, 10R5, 25R4 (m-22, n-23)) and the Iconol (registered trademark) TDA series (TDA-6, TDA-9, TDA-10), all manufactured by BASF.

[0350] The nonionic surfactants themselves provide a polymerization field and can also act as nucleation sites by initially transferring radicals to give many low molecular weight fluoropolymers.

[0351] The nonionic surfactant is preferably a nonionic surfactant that does not contain fluorine. Examples include ether-type nonionic surfactants such as polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, and polyoxyethylene alkylene alkyl ether; polyoxyethylene derivatives such as ethylene oxide / propylene oxide block copolymers; ester-type nonionic surfactants such as sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, and polyoxyethylene fatty acid ester; and amine-based nonionic surfactants such as polyoxyethylene alkylamine and alkylalkanolamide. Among these, polyoxyethylene alkyl ethers are preferred.

[0352] In the above nonionic surfactants, the hydrophobic group may be any of an alkylphenol group, a linear alkyl group, and a branched alkyl group.

[0353] The nonionic surfactant is preferably a nonionic surfactant represented by general formula (i). R 6 -OA 1 -H(i) (In the formula, R 6 is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms, and A 1 is a polyoxyalkylene chain.

[0354] In general formula (i), R 6 The number of carbon atoms in R is preferably 10 to 16, and more preferably 12 to 16. 6 When the carbon number of R is 16 or less, the composition is likely to have excellent aggregation suppression properties during stirring. 6 If the carbon number exceeds 18, the flow temperature is high and it is difficult to handle.

[0355] Above R 6 is represented by the following general formula (i-1): CH2R 31 R 32 - (i-1) (In the formula, R 31 represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms, and R 32 represents an alkyl group having 1 to 17 carbon atoms, and R 31 and R 32 The total number of carbon atoms in R is preferably 7 to 17. 31 is more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, even more preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and even more preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. 32 As the alkyl group, an alkyl group having 1 to 15 carbon atoms is more preferable, an alkyl group having 1 to 14 carbon atoms is even more preferable, and an alkyl group having 1 to 13 carbon atoms is even more preferable.

[0356] Above R 6 is preferably an alkyl group having 8 to 18 carbon atoms and an average number of methyl groups of 2.0 or more. 3The average number of methyl groups in R is more preferably 2.5 or more, even more preferably 3.0 or more, even more preferably 3.5 or more, and particularly preferably 4.0 or more. 3 The upper limit of the average number of methyl groups is preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less.

[0357] Also, the above R 6 The average number of methyl groups per molecule is preferably 4.0 or more, more preferably 4.3 or more, even more preferably 4.7 or more, and most preferably 5.0 or more. 6 In this specification, the average number of methyl groups is determined by adding methanol to a sample, performing Soxhlet extraction, and then measuring the amount of the extracted 1 This value is determined by measuring with H-NMR.

[0358] The polyoxyalkylene chain may be composed of oxyethylene and oxypropylene. It is a polyoxyalkylene chain having an average repeat number of 5 to 20 oxyethylene groups and an average repeat number of 0 to 2 oxypropylene groups, and is a hydrophilic group. The number of oxyethylene units may include either a broad or narrow unimodal distribution, which is usually provided, or a broader or bimodal distribution obtained by blending. When the average repeat number of oxypropylene groups is more than 0, the oxyethylene groups and oxypropylene groups in the polyoxyalkylene chain may be arranged in a block or random configuration. From the viewpoints of the viscosity of the composition and the ability to inhibit aggregation during stirring, a polyoxyalkylene chain having an average repeat number of 7 to 12 oxyethylene groups and an average repeat number of 0 to 2 oxypropylene groups is preferred. In particular, A 1 If the oxypropylene group has an average of 0.5 to 1.5, low foaming properties are favorable and it is preferable.

[0359] More preferably, R 6is (R')(R")HC-, where R' and R" are the same or different straight, branched, or cyclic alkyl groups having a total of at least 5, preferably 7 to 17 carbon atoms. Preferably, at least one of R' or R" is a branched or cyclic hydrocarbon group.

[0360] Specific examples of the polyoxyethylene alkyl ether include C 13 H 27 -O-(C2H4O) 10 -H, C 12 H 25 -O-(C2H4O) 10 -H, C 10 H 21 CH(CH3)CH2-O-(C2H4O)9-H, C 13 H 27 -O-(C2H4O)9-(CH(CH3)CH2O)-H, C 16 H 33 -O-(C2H4O) 10 -H, HC(CH 11 )(C7H 15 )-O-(C2H4O)9-H, etc. Commercially available polyoxyethylene alkyl ethers include, for example, Genapol X080 (product name, manufactured by Clariant), the Noigen TDS series (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) such as Noigen TDS-80 (trade name) and Noigen TDS-100 (trade name), the Leocol TD series (manufactured by Lion Chemical Industries, Ltd.) such as Leocol TD-90 (trade name), the Lionol (registered trademark) TD series (manufactured by Lion Chemical Industries, Ltd.), the T-Det A series (manufactured by Harcros Chemicals) such as T-Det A138 (trade name), the Tergitol (registered trademark) 15-S series (manufactured by The Dow Chemical Company), and Dispanol TOC (trade name, manufactured by NOF Corporation).

[0361] The nonionic surfactant is preferably an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 4 to about 18 ethylene oxide units, an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 6 to about 12 ethylene oxide units, or a mixture thereof. Nonionic surfactants of this type are also commercially available, for example, as TERGITOL TMN-6, TERGITOL TMN-10, and TERGITOL TMN-100X (all product names, manufactured by The Dow Chemical Company).

[0362] The hydrophobic group of the nonionic surfactant may be any of an alkylphenol group, a linear alkyl group, and a branched alkyl group. For example, the nonionic surfactant may be a surfactant represented by the general formula (ii): R 7 -C6H4-OA 2 -H (ii) (In the formula, R 7 is a linear or branched primary or secondary alkyl group having 4 to 12 carbon atoms, and A 2 is a polyoxyalkylene chain.) Specific examples of the nonionic surfactant include Triton X-100 (trade name, manufactured by Dow Chemical Company).

[0363] The nonionic surfactant also includes polyol compounds. Specific examples include those described in International Publication No. 2011 / 014715. Typical examples of polyol compounds include compounds having one or more sugar units as polyol units. The sugar units may be modified to contain at least one long chain. Suitable polyol compounds containing at least one long chain moiety include, for example, alkyl glycosides, modified alkyl glycosides, sugar esters, and combinations thereof. Sugars include, but are not limited to, monosaccharides, oligosaccharides, and sorbitan. Monosaccharides include pentoses and hexoses. Typical examples of monosaccharides include ribose, glucose, galactose, mannose, fructose, arabinose, and xylose. Oligosaccharides include oligomers of 2 to 10 identical or different monosaccharides. Examples of oligosaccharides include, but are not limited to, sucrose, maltose, lactose, raffinose, and isomaltose.

[0364] Typically, sugars suitable for use as polyol compounds include cyclic compounds containing a five-membered ring with four carbon atoms and one heteroatom (typically oxygen or sulfur, but preferably oxygen), or a six-membered ring with five carbon atoms and one heteroatom, preferably oxygen, as described above. These further contain at least two or at least three hydroxyl groups (-OH groups) attached to the carbon ring atoms. Typically, the sugars are modified in that one or more of the hydrogen atoms of the hydroxyl groups (and / or hydroxyalkyl groups) attached to the carbon ring atoms are replaced with long-chain residues, such that an ether or ester bond is created between the long-chain residue and the sugar moiety. Sugar-based polyols may contain one sugar unit or multiple sugar units. One sugar unit or multiple sugar units may be modified with a long-chain moiety as described above. Specific examples of sugar-based polyol compounds include glycosides, sugar esters, sorbitan esters, and mixtures and combinations thereof.

[0365] A preferred class of polyol compounds are the alkyl or modified alkyl glucosides. These classes of surfactants contain at least one glucose moiety. [ka] (wherein x represents 0, 1, 2, 3, 4, or 5; R 1 and R 2 independently represent H or a long chain unit containing at least 6 carbon atoms, with the proviso that R 1 and R 2 and at least one of R is not H. 1 and R 2 Typical examples of alkyl polyglucosides include fatty alcohol residues. Examples of fatty alcohols include hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol (lauryl alcohol), tetradecanol, hexadecanol (cetyl alcohol), heptadecanol, octadecanol (stearyl alcohol), eicosanoic acid, and combinations thereof. While the above formula represents a specific example of an alkyl polyglucoside showing glucose in the pyranose form, it is understood that other sugars or sugars of the same sugar but in different enantiomeric or diastereomeric forms may also be used. Alkyl glucosides can be obtained, for example, by the acid-catalyzed reaction of glucose, starch, or n-butyl glucoside with aliphatic alcohols, typically resulting in a mixture of various alkyl glucosides (Alkylpolygylcoside, Rompp, Lexikon Chemie, Version 2.0, Stuttgart / New York, Georg Thieme Verlag, 1999). Examples of aliphatic alcohols include hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol (lauryl alcohol), tetradecanol, hexadecanol (cetyl alcohol), heptadecanol, octadecanol (stearyl alcohol), eicosanoic acid, and combinations thereof. Alkyl glucosides are also commercially available from Cognis GmbH, Dusseldorf, Germany, under the trade names GLUCOPON or DISPONIL.

[0366] Other nonionic surfactants include difunctional block copolymers supplied by BASF as part of the Pluronic® R series, and tridecyl alcohol alkoxylates supplied by BASF as part of the Iconol® TDA series.

[0367] The nonionic surfactant is preferably at least one selected from the group consisting of nonionic surfactants represented by general formula (i) and nonionic surfactants represented by general formula (ii), and more preferably nonionic surfactants represented by general formula (i).

[0368] The nonionic surfactant preferably does not contain an aromatic moiety.

[0369] The nonionic surfactant may be a mixture of two different nonionic surfactants, for example, A 1and a compound having a polyoxyalkylene chain with an average number of oxyethylene units of 7.0 to 12.0 and an average number of oxypropylene units of 0.0 to 2.0, and A 1 It may also be a mixture with a compound which is a polyoxyalkylene chain having an average number of oxyethylene units of 10.0 to 12.0. In addition, for example, A in the above general formula (i) 1 and a compound having an average number of oxyethylene units of 7.0 or more and less than 10.0, and A 1 The compound may be a mixture of the above with a compound having a polyoxyalkylene chain with an average number of oxyethylene units of 10.0 or more and 12.0 or less.

[0370] The nonionic surfactant preferably has an HLB of 13.00 or higher, more preferably 13.20 or higher, even more preferably 14.00 or higher, even more preferably 14.05 or higher, and particularly preferably 14.10 or higher. The HLB is preferably 14.50 or lower, more preferably 14.40 or lower, even more preferably 14.30 or lower, even more preferably 14.20 or lower, and particularly preferably 14.15 or lower. The HLB is a value calculated using the Griffin formula: HLB = E / 5 (where E is the weight percent of ethylene oxide in the molecule); HLB = (E + P) / 5 (where E is as defined above, P is the weight percent of polyhydric alcohol in the molecule); HLB = 20(1 - S / N) / 5 (where S is the saponification value of the ester, and N is the neutralization value of the fatty acid constituting the ester). When two or more nonionic surfactants are used, the HLB is calculated from the HLB of each nonionic surfactant and its mass ratio. For example, if the total content of nonionic surfactants is 60 mass% with a nonionic surfactant having an HLB of 14.00 and 40 mass% with a nonionic surfactant having an HLB of 15.00, the HLB is calculated as 14.00 × 0.6 + 15.00 × 0.4 = 14.40.

[0371] The coating composition of the present disclosure may contain two nonionic surfactants with different HLBs. For example, the coating composition of the present disclosure may contain a nonionic surfactant with an HLB of 13.00 or more and less than 14.10, and a nonionic surfactant with an HLB of 14.10 or more and 15.00 or less. Adding nonionic surfactants with different HLBs can suppress foaming without adding an antifoaming agent. Also, for example, the coating composition of the present disclosure may contain a nonionic surfactant with an HLB of 13.00 or more and less than 13.50, and a nonionic surfactant with an HLB of 13.50 or more and 15.00 or less (preferably 14.50 or less, more preferably 14.00 or less).

[0372] The cloud point of a nonionic surfactant is a measure of the solubility of the surfactant in water and is preferably 30 to 90°C, more preferably 35 to 85°C, even more preferably 40 to 80°C, and particularly preferably 45 to 75°C.

[0373] The coating composition of the present disclosure may contain two nonionic surfactants with different cloud points. For example, the coating composition of the present disclosure may contain a nonionic surfactant with a cloud point of 30°C or higher and 60°C or lower and a nonionic surfactant with a cloud point of more than 60°C and less than 90°C, or may contain a nonionic surfactant with a cloud point of 35 to 60°C and a nonionic surfactant with a cloud point of 65 to 80°C. The use of a nonionic surfactant with a high cloud point can improve aggregation suppression during stirring. Furthermore, the addition of nonionic surfactants with different cloud points can suppress foaming without the addition of an antifoaming agent. Furthermore, the coating composition of the present disclosure may contain a nonionic surfactant with a cloud point of 30°C or higher and 60°C or lower and a nonionic surfactant with a cloud point of more than 60°C and less than 90°C, or may contain a nonionic surfactant with a cloud point of 35 to 60°C and a nonionic surfactant with a cloud point of 65 to 80°C.

[0374] The content of the nonionic surfactant in the first coating composition of the present disclosure is preferably 1.0% by mass or more, more preferably 2.0% by mass or more, even more preferably 3.0% by mass or more, and particularly preferably 4.0% by mass or more, relative to the fluororesin. The content of the nonionic surfactant is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 12% by mass or less, relative to the fluororesin. By keeping the content of the nonionic surfactant within the above range, the coating composition can be improved in its ability to inhibit aggregation during stirring.

[0375] The content of the nonionic surfactant in the second coating composition and the third coating composition of the present disclosure is preferably 1.0% by mass or more, more preferably 2.0% by mass or more, even more preferably 3.0% by mass or more, and particularly preferably 4.0% by mass or more, relative to PTFE. The content of the nonionic surfactant is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 12% by mass or less, relative to PTFE. By keeping the content of the nonionic surfactant within the above range, the coating composition can be improved in its ability to inhibit aggregation during stirring.

[0376] <Anionic hydrocarbon surfactants> The third coating composition of the present disclosure contains an anionic hydrocarbon surfactant. The first and second coating compositions of the present disclosure preferably contain an anionic hydrocarbon surfactant. The use of an anionic hydrocarbon surfactant can appropriately adjust the viscosity of the coating composition and improve the compatibility of pigments, fillers, and the like.

[0377] Anionic hydrocarbon surfactants typically have a hydrophilic portion, such as a carboxylate, sulfonate, or sulfate, and a hydrophobic portion, which is a long chain hydrocarbon moiety, such as an alkyl.

[0378] Examples of anionic hydrocarbon surfactants include Versatic (registered trademark) 10 manufactured by Resolution Performance Products and Avanel S series (S-70, S-74, etc.) manufactured by BASF.

[0379] The anionic hydrocarbon surfactants include RLM (wherein R is a linear or branched alkyl group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group having 3 or more carbon atoms which may have a substituent, and when the alkyl group has 3 or more carbon atoms, it may contain a monovalent or divalent heterocycle or may form a ring). L is -ArSO3 - , -SO3 - , -SO4-, -PO3 - or -COO - and M is H, a metal atom, or NR 5 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group, -ArSO3 - is an aryl sulfonate. )

[0380] Specifically, CH3-(CH2) such as lauric acid and lauryl sulfate n -LM (wherein n is an integer of 6 to 17, and L and M are the same as above). A mixture in which R is an alkyl group having 12 to 16 carbon atoms and LM is a sulfate can also be used.

[0381] In addition, the anionic hydrocarbon surfactants include R 6 (-LM)2(wherein, R 6is a linear or branched alkylene group having one or more carbon atoms which may have a substituent, or a cyclic alkylene group having three or more carbon atoms which may have a substituent, and when the number of carbon atoms is three or more, it may contain a monovalent or divalent heterocycle or may form a ring. - , -SO3 - , -SO4-, -PO3 - or -COO - and M is H, a metal atom, or NR 5 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group, -ArSO3 - is an aryl sulfonate. )

[0382] In addition, the anionic hydrocarbon surfactants include R 7 (-LM)3(wherein, R 7 is a linear or branched alkylidyne group having one or more carbon atoms which may have a substituent, or a cyclic alkylidyne group having three or more carbon atoms which may have a substituent, and when the number of carbon atoms is three or more, it may contain a monovalent or divalent heterocycle or may form a ring. - , -SO3 - , -SO4-, -PO3 - or -COO - and M is H, a metal atom, or NR 5 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 5 is H or an organic group. -ArSO3 - is an aryl sulfonate. )

[0383] In addition, anionic hydrocarbon surfactants also include siloxane hydrocarbon surfactants.Siloxane hydrocarbon surfactants include those described in Silicone Surfactants, R.M. Hill, Marcel Dekker, Inc., ISBN: 0-8247-00104.The structure of siloxane hydrocarbon surfactants comprises a distinct hydrophobic portion and a hydrophilic portion.The hydrophobic portion comprises one or more dihydrocarbylsiloxane units, where the substituents on the silicone atom are completely hydrocarbon.These siloxane surfactants can also be considered hydrocarbon surfactants in the sense that the carbon atoms of the hydrocarbyl group are completely substituted with hydrogen atoms, even if they can be substituted with halogens such as fluorine, i.e., the monovalent substituents on the carbon atoms of the hydrocarbyl group are hydrogen.

[0384] The hydrophilic portion of the siloxane hydrocarbon surfactant may contain one or more polar moieties containing ionic groups such as sulfates, sulfonates, phosphonates, phosphate esters, carboxylates, carbonates, sulfosuccinates, taurates (as free acids, salts, or esters), phosphine oxides, betaines, betaine copolyols, and quaternary ammonium salts. The ionic hydrophobic portion may also contain ionically functionalized siloxane grafts. Examples of such siloxane hydrocarbon surfactants include polydimethylsiloxane-grafted (meth)acrylates, polydimethylsiloxane-grafted polyacrylate salts, and polydimethylsiloxane-grafted quaternary amines. The polar portion of the hydrophilic portion of the siloxane hydrocarbon surfactant may contain nonionic groups formed by polyethers such as polyethylene oxide (PEO) and mixed polyethylene oxide / propylene oxide polyethers (PEO / PPO); monosaccharides and disaccharides; and water-soluble heterocycles such as pyrrolidinone. The ratio of ethylene oxide to propylene oxide (EO / PO) can be varied in mixed polyethylene oxide / propylene oxide polyethers.

[0385] The hydrophilic portion of the siloxane hydrocarbon surfactant may also contain a combination of ionic and nonionic moieties. Such moieties include, for example, ionically end-functionalized or randomly functionalized polyethers or polyols. Preferred for the practice of the present disclosure are siloxanes with nonionic moieties, i.e., nonionic siloxane surfactants.

[0386] The arrangement of hydrophobic and hydrophilic moieties in the structure of the siloxane hydrocarbon surfactant may take the form of a diblock polymer (AB), a triblock polymer (ABA) (where "B" represents the siloxane portion of the molecule), or a multiblock polymer. Alternatively, the siloxane surfactant may comprise a graft polymer.

[0387] Siloxane hydrocarbon surfactants are also disclosed in US Pat. No. 6,841,616.

[0388] Siloxane-based anionic hydrocarbon surfactants include SilSense, available from Noveon® Consumer Specialties of Lubrizol Advanced Materials, Inc. TM PE-100 Silicone, SilSense TM CA-1 silicone and the like.

[0389] Examples of anionic hydrocarbon surfactants include Lankropol® K8300, a sulfosuccinate surfactant from Akzo Nobel Surface Chemistry LLC. Examples of sulfosuccinate surfactants include sodium diisodecyl sulfosuccinate (Emulsogen® SB10 from Clariant) and sodium diisotridecyl sulfosuccinate (Polirol® TR / LNA from Cesapinia Chemicals).

[0390] Anionic hydrocarbon surfactants include PolyFox (registered trademark) surfactants from Omnova Solutions, Inc. TM PF-156A, PolyFox TM PF-136A, etc.)

[0391] Examples of anionic hydrocarbon surfactants include those represented by the general formula (α): R 10 -COOM (α) (In the formula, R 10 is a monovalent organic group containing one or more carbon atoms. M is H, a metal atom, NR 11 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 11 R is H or an organic group, and may be the same or different. 11 as H or C 1-10 is preferably an organic group represented by the formula: 1-4 From the viewpoint of surface activity, the organic group R 10 The number of carbon atoms in R is preferably 2 or more, and more preferably 3 or more. 10 The number of carbon atoms in is preferably 29 or less, more preferably 23 or less. The metal atom of M includes alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K, or Li is preferred. M may be H, a metal atom, or NR 11 4 is preferred, H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR 11 4 is more preferred, H, Na, K, Li or NH4 is even more preferred, Na, K or NH4 is even more preferred, Na or NH4 is particularly preferred, and NH4 is most preferred.

[0392] Compound (α) includes R 12 -COOM(in the formula, R 12is a linear or branched alkyl group, alkenyl group, alkylene group or alkenylene group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group, alkenyl group, alkylene group or alkenylene group having 3 or more carbon atoms which may have a substituent, and these may contain an ether bond. When the carbon number is 3 or more, it may contain a monovalent or divalent heterocycle or may form a ring. M is the same as above. ) are also included. Specifically, CH3-(CH2) n -COOM (wherein n is an integer of 2 to 28, and M is the same as above).

[0393] From the viewpoint of emulsion stability, the compound (α) may be one that does not contain a carbonyl group (excluding the carbonyl group in a carboxyl group). Examples of the hydrocarbon-containing surfactant that does not contain a carbonyl group include those represented by the following formula (A): R-COO-M(A) (wherein R is an alkyl group, an alkenyl group, an alkylene group, or an alkenylene group, which may contain an ether bond. M is H, a metal atom, NR 11 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. 11 are the same or different and are H or an organic group having 1 to 10 carbon atoms.) is a preferred example. In the above formula (A), R is preferably an alkyl group or an alkenyl group (which may contain an ether group). The alkyl group or alkenyl group in the above R may be linear or branched. The number of carbon atoms in the above R is not limited, but is, for example, 2 to 29.

[0394] When the alkyl group is linear, R preferably has 3 to 29 carbon atoms, and more preferably 5 to 23. When the alkyl group is branched, R preferably has 5 to 35 carbon atoms, and more preferably 11 to 23. When the alkenyl group is linear, R preferably has 2 to 29 carbon atoms, and more preferably 9 to 23. When the alkenyl group is branched, R preferably has 2 to 29 carbon atoms, and more preferably 9 to 23.

[0395] Examples of the alkyl group and alkenyl group include a methyl group, an ethyl group, an isobutyl group, a t-butyl group, and a vinyl group.

[0396] Further, examples of the anionic hydrocarbon surfactant include carboxylic acid hydrocarbon surfactants. Examples of the carboxylic acid hydrocarbon surfactant include butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, palmitoleic acid, margaric acid, stearic acid, oleic acid, vaccenic acid, linoleic acid, (9,12,15)-linolenic acid, (6,9,12)linolenic acid, eleostearic acid, arachidic acid, 8,11-eicosadienoic acid, mead acid, arachidonic acid, behenic acid, lignoceric acid, nervonic acid, cerotic acid, montanic acid, melissic acid, crotonic acid, myrisic acid, methylparaben ... Examples of suitable salts include oleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, eicosenoic acid, erucic acid, nervonic acid, linoleic acid, eicosadienoic acid, docosadienoic acid, linolenic acid, pinolenic acid, α-eleostearic acid, β-eleostearic acid, mead acid, dihomo-γ-linolenic acid, eicosatrienoic acid, stearidonic acid, arachidonic acid, eicosatetraenoic acid, adrenic acid, bosseopentaenoic acid, eicosapentaenoic acid, osbondoic acid, sardine acid, tetracosapentaenoic acid, docosahexaenoic acid, herring acid, and salts thereof. Particularly preferred are at least one selected from the group consisting of lauric acid, capric acid, myristic acid, pentadecylic acid, palmitic acid, and salts thereof. The salts include those in which the hydrogen atom of the carboxyl group is bonded to a metal atom of the formula M, NR 11 4. Examples include, but are not limited to, imidazolium which may have a substituent, pyridinium which may have a substituent, or phosphonium which may have a substituent.

[0397] Furthermore, examples of anionic hydrocarbon surfactants that can be used include those described in International Publication Nos. 2013 / 146950 and 2013 / 146947. Examples include those having a saturated or unsaturated aliphatic chain with 6 to 40 carbon atoms, preferably 8 to 20 carbon atoms, and more preferably 9 to 13 carbon atoms. The saturated or unsaturated aliphatic chain may be either a linear or branched chain, or may have a cyclic structure. The hydrocarbon may be aromatic or may have an aromatic group. The hydrocarbon may have a heteroatom such as oxygen, nitrogen, or sulfur.

[0398] Examples of anionic hydrocarbon surfactants include alkyl sulfonates, alkyl sulfates, alkylaryl sulfates, and salts thereof; aliphatic (carboxylic) acids and salts thereof; alkyl phosphates, alkylaryl phosphates, and salts thereof; and among these, alkyl sulfonates, alkyl sulfates, aliphatic carboxylic acids, and salts thereof are preferred.

[0399] As the alkyl sulfate or its salt, ammonium lauryl sulfate and sodium lauryl sulfate are preferred. The aliphatic carboxylic acid or a salt thereof is preferably succinic acid, decanoic acid, undecanoic acid, undecenoic acid, lauric acid, hydrododecanoic acid, or a salt thereof.

[0400] The content of the anionic hydrocarbon surfactant in the first coating composition of the present disclosure is preferably 10 ppm to 5000 ppm relative to the fluororesin, depending on the types of other compounding ingredients. The lower limit of the content of the anionic hydrocarbon surfactant is more preferably 50 ppm or more, even more preferably 100 ppm or more, more preferably 4000 ppm or less, and even more preferably 3000 ppm or less relative to the fluororesin. By keeping the content of the anionic hydrocarbon surfactant within the above range, it is possible to appropriately adjust the viscosity of the coating composition and improve the miscibility of pigments, fillers, etc., while suppressing excessive foaming.

[0401] In the second coating composition and the third coating composition of the present disclosure, the content of the anionic hydrocarbon surfactant in the coating composition is preferably 10 ppm to 5000 ppm relative to PTFE, depending on the types of other compounding ingredients. The lower limit of the content of the anionic hydrocarbon surfactant is more preferably 50 ppm or more, even more preferably 100 ppm or more, more preferably 4000 ppm or less, and even more preferably 3000 ppm or less relative to PTFE. By keeping the content of the anionic hydrocarbon surfactant within the above range, it is possible to appropriately adjust the viscosity of the coating composition and improve the miscibility of pigments, fillers, etc., while suppressing excessive foaming.

[0402] The third coating composition of the present disclosure is substantially free of fluorine-containing compounds having hydrophilic groups (excluding the monomer (I) and polymer (I) represented by general formula (I)). The first and second coating compositions of the present disclosure may contain fluorine-containing compounds having hydrophilic groups, but preferably are substantially free of fluorine-containing compounds having hydrophilic groups (excluding the monomer (I) and polymer (I) represented by general formula (I)).

[0403] In the present disclosure, "substantially free of fluorine-containing compounds having hydrophilic groups" means that the content of fluorine-containing compounds having hydrophilic groups in the coating composition is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 25 ppb by mass or less, still more preferably 10 ppb by mass or less, particularly preferably 1 ppb by mass or less, and most preferably the content of fluorine-containing compounds having hydrophilic groups is below the detection limit when measured by liquid chromatography-mass spectrometry (LC / MS).

[0404] In another embodiment of the coating composition of the present disclosure, the coating composition is substantially free of a fluorine-containing surfactant.

[0405] In the present disclosure, "substantially free of fluorine-containing surfactant" means that the content of fluorine-containing surfactant in the coating composition is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, still more preferably 1 ppb by mass or less, and particularly preferably below the detection limit of fluorine-containing surfactant as measured by liquid chromatography-mass spectrometry (LC / MS).

[0406] In another embodiment of the coating composition of the present disclosure, the coating composition is substantially free of anionic fluorine-containing surfactants.

[0407] In the present disclosure, "substantially free of anionic fluorine-containing surfactants" means that the content of anionic fluorine-containing surfactants in the coating composition is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, still more preferably 1 ppb by mass or less, and particularly preferably below the detection limit when measured by liquid chromatography-mass spectrometry (LC / MS).

[0408] In another embodiment of the coating composition of the present disclosure, the coating composition is substantially free of fluorine-containing anionic surfactants in which the molecular weight of the anionic moiety is 800 or less.

[0409] In the present disclosure, "substantially free of fluorine-containing anionic surfactants whose anionic moiety has a molecular weight of 800 or less" means that the content of fluorine-containing anionic surfactants whose anionic moiety has a molecular weight of 800 or less in the paint composition is 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, still more preferably 1 ppb by mass or less, and particularly preferably below the detection limit by liquid chromatography-mass spectrometry (LC / MS).

[0410] The content of the fluorine-containing compound having a hydrophilic group can be determined by a known method, for example, by adding methanol to the composition, extracting the composition, and analyzing the resulting extract by LC / MS. To further increase the extraction efficiency, treatment such as Soxhlet extraction or ultrasonic treatment may be carried out. Molecular weight information is extracted from the obtained LC / MS spectrum, and its match with the structural formula of the candidate fluorine-containing compound containing a hydrophilic group is confirmed. Then, aqueous solutions containing five or more levels of the confirmed fluorine-containing compound containing a hydrophilic group are prepared, and LC / MS analysis is performed on the aqueous solutions containing each level of the fluorine-containing compound. The relationship between the content and the area for that content is plotted, and a calibration curve is drawn. Then, using the calibration curve, the area of ​​the LC / MS chromatogram of the fluorine-containing compound having a hydrophilic group in the extract can be converted into the content of the fluorine-containing compound having a hydrophilic group.

[0411] Examples of the fluorine-containing compound containing a hydrophilic group include a fluorine-containing surfactant, a fluorine-containing telomer containing a hydrophilic group, a fluorine-containing oligomer containing a hydrophilic group, a perfluoropolyether carboxylic acid, and a perfluoropolyether sulfonic acid.

[0412] Examples of hydrophilic groups include -NH, -PO, -P(O)(OM), -OPO, -OP(O)(OM), -SO, -OSO, and -COOM (in each formula, M represents H, a metal atom, or NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring.) Of these, -SO3M or -COOM is preferred as the hydrophilic group.

[0413] Examples of the fluorine-containing surfactant include anionic fluorine-containing surfactants, etc. The anionic fluorine-containing surfactant may be, for example, a surfactant containing fluorine atoms and having a total carbon number of 20 or less excluding the anionic group.

[0414] The fluorine-containing surfactant may be a surfactant containing fluorine, the molecular weight of which in the anionic moiety is 800 or less. The "anionic moiety" refers to the moiety excluding the cation of the fluorine-containing surfactant. For example, F(CF2) represented by the formula (I) described below may be used. n1 In the case of COOM, "F(CF2) n1 The "COO" part.

[0415] The above-mentioned fluorine-containing surfactant also includes a fluorine-containing surfactant having a LogPOW of not more than 3.5. The LogPOW is a partition coefficient between 1-octanol and water, and is expressed as LogP (where P represents the ratio of the fluorine-containing surfactant concentration in octanol to the fluorine-containing surfactant concentration in water when a 1:1 octanol / water mixture containing the fluorine-containing surfactant undergoes phase separation). The LogPOW is calculated from the HPLC elution time of the sample solution using standard substances (heptanoic acid, octanoic acid, nonanoic acid, and decanoic acid) with known octanol / water partition coefficients under the following conditions: column: TOSOH ODS-120T column (φ4.6 mm×250 mm, manufactured by Tosoh Corporation), eluent: acetonitrile / 0.6% by mass HClO₄ water = 1 / 1 (vol / vol%), flow rate: 1.0 mL / min, sample amount: 300 μL, column temperature: 40°C, detection light: UV 210 nm. A calibration curve between each elution time and the known octanol / water partition coefficient is then prepared, and the LogPOW is calculated from the HPLC elution time of the sample solution based on this calibration curve.

[0416] Specific examples of the fluorine-containing surfactants include those described in U.S. Patent Application Publication Nos. 2007 / 0015864, 2007 / 0015865, 2007 / 0015866, 2007 / 0276103, 2007 / 0117914, 2007 / 142541, 2008 / 0015319, and U.S. Pat. No. 3,250,808. , U.S. Pat. No. 3,271,341, JP 2003-119204 A, WO 2005 / 042593, WO 2008 / 060461, WO 2007 / 046377, WO 2007 / 119526, WO 2007 / 046482, WO 2007 / 046345, U.S. Patent Application Publication No. 2014 / 0228531, WO 2013 / 189824, and WO 2013 / 189826.

[0417] The anionic fluorine-containing surfactants include those represented by the general formula (N 0 ): X n0 -Rf n0 -Y 0 (N 0 ) (In the formula, X n0 is H, Cl or F. n0 is a linear, branched or cyclic alkylene group having 3 to 20 carbon atoms, in which some or all of the H atoms have been substituted with F, and the alkylene group may contain one or more ether bonds, and some of the H atoms may have been substituted with Cl. Y 0 is an anionic group.

[0418] Y 0 The anionic group may be -COOM, -SO2M, or -SO3M, and may be -COOM or -SO3M, where M is H, a metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R7 is H or an organic group. The metal atom includes alkali metals (Group 1) and alkaline earth metals (Group 2), such as Na, K, or Li. R 7 As for H or C 1-10 may be an organic group of H or C 1-4 may be an organic group of H or C 1-4 M may be H, a metal atom, or an alkyl group represented by the formula: 7 4, and may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR 7 4, and may be H, Na, K, Li, or NH4. n0 may be one in which 50% or more of H is substituted with fluorine.

[0419] General formula (N 0 The compound represented by the general formula (N 1 ): X n0 -(CF2) m1 -Y 0 (N 1 ) (In the formula, X n0 is H, Cl, or F, m1 is an integer of 3 to 15, and Y 0 is as defined above, a compound represented by the general formula (N 2 ): Rf n1 -O-(CF(CF3)CF2O) m2 CFX n1 -Y 0 (N 2 ) (In the formula, Rf n1 is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer of 0 to 3, and X n1 is F or CF3, and Y 0 is as defined above, a compound represented by the general formula (N 3 ): Rf n2 (CH2) m3 -(Rf n3 ) q -Y 0 (N 3 ) (In the formula, Rf n2 is a partially or fully fluorinated alkyl group having 1 to 13 carbon atoms which may contain an ether bond, m3 is an integer of 1 to 3, and Rf n3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, q is 0 or 1, and Y 0 is as defined above, a compound represented by the general formula (N 4 ): Rf n4 -O-(CY n1 Y n2 ) p CF2-Y 0 (N 4 ) (In the formula, Rf n4 is a linear or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms, which may contain an ether bond and / or a chlorine atom, and Y n1 and Y n2 are the same or different and are H or F, p is 0 or 1, and Y 0 is as defined above, a compound represented by the general formula (N 5 ): [ka] (In the formula, X n2 , X n3 and X n4 Rf may be the same or different and are H, F, or a linear or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond. n5 is a linear or branched partially or fully fluorinated alkylene group having 1 to 3 carbon atoms, which may contain an ether bond; L is a linking group; Y 0 is as defined above, where X n2 , X n3 , X n4 and Rf n5 The total number of carbon atoms is 18 or less.

[0420] General formula (N 0) More specifically, the compounds represented by the general formula (I) are perfluorocarboxylic acids (I), ω-H perfluorocarboxylic acids (II), general formula (III), perfluoropolyether carboxylic acids (III), general formula (IV), perfluoroalkyl alkylene carboxylic acids (IV), general formula (V), perfluoroalkoxy fluorocarboxylic acids (V), general formula (VI), perfluoroalkyl sulfonic acids (VI), general formula (VII), ω-H perfluoro sulfonic acids (VII), general formula (VIII), perfluoroalkyl alkylene sulfonic acids (VIII), general formula (IX), alkyl alkylene carboxylic acids (IX), general formula (X), fluorocarboxylic acids (X), general formula (XI), alkoxy fluoro sulfonic acids (XI), general formula (XII), and general formula (XIII) are represented by the following general formula (XIII).

[0421] The perfluorocarboxylic acid (I) is represented by the general formula (I): F(CF2) n1 COOM (I) (wherein n1 is an integer of 3 to 14, and M is H, a metal atom, or NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0422] The ω-H perfluorocarboxylic acid (II) is represented by the general formula (II): H(CF2) n2 COOM (II) (wherein n2 is an integer of 4 to 15, and M is as defined above).

[0423] The perfluoropolyether carboxylic acid (III) is represented by the general formula (III): Rf 1 -O-(CF(CF3)CF2O) n3CF(CF3)COOM (III) (In the formula, Rf 1 is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer of 0 to 3, and M is as defined above.

[0424] The perfluoroalkyl alkylene carboxylic acid (IV) is represented by the general formula (IV): Rf 2 (CH2) n4 Rf 3 COOM (IV) (In the formula, Rf 2 is a perfluoroalkyl group having 1 to 5 carbon atoms, and Rf 3 is a linear or branched perfluoroalkylene group having 1 to 3 carbon atoms, n4 is an integer of 1 to 3, and M is as defined above.

[0425] The alkoxyfluorocarboxylic acid (V) is represented by the general formula (V): Rf 4 -O-CY 1 Y 2 CF2-COOM (V) (In the formula, Rf 4 is a linear or branched partially or fully fluorinated alkyl group having 1 to 12 carbon atoms, which may contain an ether bond and / or a chlorine atom, and Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.

[0426] The perfluoroalkylsulfonic acid (VI) is represented by the general formula (VI): F(CF2) n5 SO3M (VI) (wherein n5 is an integer of 3 to 14, and M is as defined above).

[0427] The ω-H perfluorosulfonic acid (VII) is represented by the general formula (VII): H(CF2) n6 SO3M (VII) (wherein n6 is an integer of 4 to 14, and M is as defined above).

[0428] The perfluoroalkyl alkylene sulfonic acid (VIII) is represented by the general formula (VIII): Rf 5 (CH2) n7 SO3M (VIII) (In the formula, Rf 5 is a perfluoroalkyl group having 1 to 13 carbon atoms, n7 is an integer of 1 to 3, and M is as defined above.

[0429] The alkyl alkylene carboxylic acid (IX) is represented by the general formula (IX): Rf 6 (CH2) n8 COOM (IX) (In the formula, Rf 6 is a linear or branched partially or fully fluorinated alkyl group having 1 to 13 carbon atoms which may contain an ether bond, n8 is an integer of 1 to 3, and M is as defined above.

[0430] The fluorocarboxylic acid (X) is represented by the general formula (X): Rf 7 -O-Rf 8 -O-CF2-COOM (X) (In the formula, Rf 7 is a linear or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond and / or a chlorine atom, and Rf 8 is a linear or branched, partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, and M is as defined above.

[0431] The alkoxyfluorosulfonic acid (XI) is represented by the general formula (XI): Rf 9 -O-CY 1 Y 2 CF2-SO3M (XI) (In the formula, Rf 9 is a linear or branched alkyl group having 1 to 12 carbon atoms, which may contain an ether bond, and which may contain chlorine, and which is partially or completely fluorinated; Y 1 and Y 2 are the same or different and are H or F, and M is as defined above.

[0432] The compound (XII) is represented by the general formula (XII): [ka] (In the formula, X 1 , X 2 and X 3 may be the same or different and are H, F and linear or branched partially or fully fluorinated alkyl groups having 1 to 6 carbon atoms which may contain ether bonds; Rf 10 is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, and Y 0 is an anionic group. 0 may be -COOM, -SO2M, or -SO3M, and may be -SO3M or COOM (wherein M is as defined above). Examples of L include a single bond, and a partially or fully fluorinated alkylene group having 1 to 10 carbon atoms which may contain an ether bond.

[0433] The compound (XIII) is represented by the following general formula (XIII): Rf 11 -O-(CF2CF(CF3)O) n9 (CF2O) n10 CF2COOM (XIII) (In the formula, Rf 11 is a fluoroalkyl group containing chlorine and having 1 to 5 carbon atoms, n9 is an integer of 0 to 3, n10 is an integer of 0 to 3, and M is as defined above. Compound (XIII) is represented by the formula: CF2ClO(CF2CF(CF3)O) n9 (CF2O) n10CF2COONH4 (a mixture having an average molecular weight of 750, wherein n9 and n10 are defined above).

[0434] Thus, examples of the anionic fluorine-containing surfactant include carboxylic acid surfactants and sulfonic acid surfactants.

[0435] The fluorine-containing surfactant may be one type of fluorine-containing surfactant or a mixture containing two or more types of fluorine-containing surfactants.

[0436] Examples of the fluorine-containing surfactant include compounds represented by the following formula: The fluorine-containing surfactant may be a mixture of these compounds. In one embodiment of the coating composition of the present disclosure, the coating composition is substantially free of compounds represented by the following formula: H(CF2)7COOM, F(CF2)7COOM, F(CF2)5COOM, H(CF2)6COOM, CF3O(CF2)3OCHFCF2COOM, C3F7OCF(CF3)CF2OCF(CF3)COOM, CF3CF2CF2OCF(CF3)COOM, CF3CF2OCF2CF2OCF2COOM, C2F5OCF(CF3)CF2OCF(CF3)COOM, CF3OCF(CF3)CF2OCF(CF3)COOM, CF2ClCF2CF2OCF(CF3)CF2OCF2COOM, CF2ClCF2CF2OCF2CF(CF3)OCF2COOM, CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM, CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM, [ka] (In each formula, M is H, metal atom, NR 74. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0437] In the present disclosure, "substantially free of compounds represented by the above formula" means that the content of compounds represented by the above formula in the paint composition is 10 ppm by mass or less in total, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, still more preferably 1 ppb by mass or less, and particularly preferably below the detection limit by liquid chromatography-mass spectrometry (LC / MS).

[0438] <Film-forming agent> In one embodiment of the coating composition of the present disclosure, a film-forming agent is contained. When a film-forming agent is contained, the coating composition can suppress the occurrence of cracks when the resulting coating film is dried, and the coating composition has excellent workability.

[0439] Examples of the film-forming agent include acrylic resins such as depolymerizable acrylic resins, urethane resins, polyethylene glycol, and polypropylene glycol.

[0440] When the coating composition of the present disclosure is applied, dried, and then baked, the depolymerizable acrylic resin gradually decomposes while maintaining its binding effect on the fluororesin, thereby preventing the occurrence of cracks.

[0441] In one embodiment of the composition of the present disclosure, a depolymerizable acrylic resin is contained in addition to PTFE. The depolymerizable acrylic resin preferably remains up to the temperature at which PTFE begins to melt (melting temperature), even if depolymerization begins below the melting point of PTFE, and decomposes and volatilizes at the baking (processing) temperature. For example, at the melting temperature of PTFE (usually 240-345°C), 5% or more, particularly 10% or more, at least 50%, and preferably at least 20%, remain, but at the baking (processing) temperature (usually above the melting temperature of PTFE and up to 415°C, preferably 360-400°C), only 10% or less, particularly 5% or less remain, and essentially none remain at the completion of baking. From this perspective, the depolymerization (decomposition) temperature of the depolymerizable acrylic resin is preferably about 200°C or higher but lower than the baking (processing) temperature. In particular, regardless of the type of resin, a depolymerizable acrylic resin that remains at approximately 25 to 50% in the temperature range of 300 to 320°C and approximately 20 to 10% in the temperature range of 330 to 345°C is suitable in terms of the balance between the effect of preventing shrinkage cracking and the effect of preventing discoloration, and any depolymerizable acrylic resin that satisfies this condition can be used.

[0442] As described in "Polym. Eng. Soi., Vol. 6, p. 273 (1966)," "Plast. Massy., Vol. 75, p. 48 (1971)," and "Deterioration of Polymer Materials," Corona Publishing, p. 144 (1958), the more branches there are in the polymer chain, the weaker the C—C and C—H bonds become, making the resin more susceptible to oxidative decomposition and depolymerization. Examples of depolymerizable acrylic resins include methacrylate resins, and specific examples thereof include those represented by the formula (5): CH2=C(CH3)COOR (5) Preferred examples include methacrylate homopolymers or copolymers essentially containing a methacrylate monomer represented by the formula (wherein R is an alkyl or hydroxyalkyl group having 1 to 5 carbon atoms). Specific examples of methacrylate monomers that are preferably used include methyl methacrylate, ethyl methacrylate, propyl methacrylate, dimethylpropyl methacrylate, butyl methacrylate, and pentyl methacrylate. Among these, depolymerizable acrylic resins containing butyl methacrylate as a monomer are preferred because of their low glass transition temperature and good depolymerizability (decomposability).

[0443] Furthermore, there is no problem if a stable emulsion can be formed using a homopolymer, but from the viewpoint of stabilizing the emulsion, a monomer having a carboxyl group or a hydroxyl group may be used as a comonomer as appropriate.

[0444] The depolymerizable acrylic resin can be used as fine particles (depolymerizable acrylic resin emulsion) produced by a method such as emulsion polymerization, and the average particle size is preferably 0.1 to 100 μm, particularly 0.2 to 1 μm. Particles with an average particle size of less than 0.1 μm tend to easily cause mud cracks, while particles with an average particle size of more than 100 μm tend to make coating difficult.

[0445] In the first coating composition of the present disclosure, the content of the depolymerizable acrylic resin is preferably 5 to 25 parts, more preferably 7 to 20 parts, and even more preferably 10 to 15 parts per 100 parts of the fluororesin, from the viewpoints of film-forming properties and prevention of discoloration of the coating film.

[0446] In the second and third coating compositions of the present disclosure, the content of the depolymerizable acrylic resin is preferably 5 to 25 parts, more preferably 7 to 20 parts, and even more preferably 10 to 15 parts per 100 parts of PTFE, from the viewpoints of film-forming properties and prevention of discoloration of the coating film.

[0447] The depolymerizable acrylic resin is preferably mixed with the other ingredients in the form of an emulsion.

[0448] <Binder resin> In one embodiment of the coating composition of the present disclosure, a binder resin is contained. When the binder resin is contained, the coating composition can provide a coating film with excellent adhesion to the substrate. The binder resin has the effect of improving the coating film hardness and gloss of the resulting coating film.

[0449] Examples of binder resins include polyamideimide (PAI), polyimide (PI), polyethersulfone (PES), polyarylene sulfide (PAS), polyetherimide, polyetheretherketone, aromatic polyester, etc. The binder resins may be used alone or in combination of two or more.

[0450] PAI is a resin made of a polymer having an amide bond and an imide bond in its molecular structure. There are no particular limitations on the PAI. Examples of PAI include, but are not limited to, resins made of high-molecular-weight polymers obtained by various reactions, such as the reaction of an aromatic diamine having an amide bond in the molecule with an aromatic tetracarboxylic acid such as pyromellitic acid; the reaction of an aromatic tricarboxylic acid such as trimellitic anhydride with a diamine such as 4,4-diaminophenyl ether or a diisocyanate such as diphenylmethane diisocyanate; and the reaction of a dibasic acid having an aromatic imide ring in the molecule with a diamine. Because of their excellent heat resistance, PAIs made of polymers having an aromatic ring in the main chain are preferred.

[0451] PI is a resin made of a polymer having an imide bond in its molecular structure. There are no particular limitations on the PI, but examples include resins made of high-molecular-weight polymers obtained by the reaction of aromatic tetracarboxylic anhydrides such as pyromellitic anhydride. Because of their excellent heat resistance, PIs made of polymers having an aromatic ring in the main chain are preferred.

[0452] PES has the following general formula:

[0453] [ka]

[0454] The PES is a resin made of a polymer having a repeating unit represented by the following formula: There are no particular limitations on the PES, but examples thereof include a resin made of a polymer obtained by polycondensation of dichlorodiphenyl sulfone and bisphenol.

[0455] PAS is a resin made of a polymer having a repeating unit represented by the general formula -[Ar-S]- (wherein Ar represents an arylene group). The PAS is not particularly limited, but examples thereof include polyphenylene sulfide (PPS).

[0456] As the binder resin, at least one selected from the group consisting of PAI, PI, PES, and PPS is preferred, as it can provide a coating film with even better adhesion to the substrate, and PAI is more preferred. Furthermore, PES is preferred as the binder resin, as it can suppress coloration during baking and increase the color flexibility of the coating film. Using a combination of PAI and PES as the binder resin is also a preferred embodiment.

[0457] In the coating composition of the present disclosure, the content of the binder resin is preferably 5% by mass or more, more preferably 8% by mass or more, and preferably 15% by mass or less, more preferably 12% by mass or less, based on the coating composition. When the content of the binder resin is within the above range, a coating film with even better adhesion to the substrate can be obtained.

[0458] In the first coating composition of the present disclosure, the mass ratio of the fluororesin to the binder resin (fluororesin / binder resin) is preferably 90 / 10 to 50 / 50, more preferably 85 / 15 to 60 / 40, and even more preferably 80 / 20 to 70 / 30. When the mass ratio of the fluororesin to the binder resin is within the above range, a coating film with even better adhesion to the substrate can be obtained.

[0459] In the second and third coating compositions of the present disclosure, the mass ratio of PTFE to binder resin (PTFE / binder resin) is preferably 90 / 10 to 50 / 50, more preferably 85 / 15 to 60 / 40, and even more preferably 80 / 20 to 70 / 30. When the mass ratio of PTFE to binder resin is within the above range, a coating film with even better adhesion to the substrate can be obtained.

[0460] The coating composition of the present disclosure may contain other components, such as preservatives, water-soluble polymer compounds, pigments, fillers, antifoaming agents, drying agents, thickeners, organic solvents, leveling agents, anti-cracking agents, dispersants, antifreezing agents, solid lubricants, anti-settling agents, moisture absorbers, surface conditioners, thixotropy-imparting agents, viscosity modifiers, anti-gelling agents, UV absorbers, HALS (light stabilizers), matting agents, plasticizers, anti-color separation agents, anti-skinning agents, anti-scratch agents, rust inhibitors, mildew inhibitors, antibacterial agents, antioxidants, flame retardants, anti-sagging agents, anti-static agents, silane coupling agents, various reinforcing agents, various extenders, conductive fillers, and colloidal silica.

[0461] The paint composition of the present disclosure contains a preservative, which makes it possible to inhibit spoilage of the paint composition and bacterial growth even when the paint composition is stored for a long period of time.

[0462] Examples of preservatives include isothiazolones, azoles, pronopol, chlorothalonil, methylsulfonyltetrachloropyrrolidin, carbentazim, fluorophorbet, sodium diacetate, and diiodomethyl-paratolyl sulfone.

[0463] The content of the preservative in the first coating composition of the present disclosure is preferably 0.01 to 0.5 mass % relative to the fluororesin, and more preferably 0.05 to 0.2 mass %. The content of the preservative in the second coating composition and the third coating composition of the present disclosure is preferably 0.01 to 0.5 mass % relative to the PTFE, and more preferably 0.05 to 0.2 mass %.

[0464] Examples of water-soluble polymer compounds include methyl cellulose, alumina sol, polyvinyl alcohol, carboxylated vinyl polymer, polyethylene oxide (dispersion stabilizer), polyethylene glycol (dispersion stabilizer), polyvinylpyrrolidone (dispersion stabilizer), phenol resin, urea resin, epoxy resin, melamine resin, polyester resin, polyether resin, acrylic silicone resin, silicone resin, silicone polyester resin, and polyurethane resin.

[0465] As the pigment, various conventionally known pigments can be used, such as titanium oxide, carbon black, red iron oxide, extender pigments, etc. In the coating composition of the present disclosure, the content of the pigment is preferably 0.1 to 20.0% by mass, and more preferably 1 to 10% by mass, relative to the coating composition.

[0466] Examples of the filler include inorganic fillers, diamond, fluorinated diamond, and carbon black.

[0467] Examples of inorganic fillers include pigments, mica particles, mica particles coated with pigments, titanium-coated mica, inorganic nitrides, carbides, borides, and oxides of zirconium, tantalum, titanium, tungsten, silicon, aluminum, or beryllium (specifically, aluminum oxide, silicon carbide, zirconium oxide, zirconium carbide, etc.), metal flakes, metal powder, clay, talc, tourmaline, jade, germanium, corundum, silica stone, chrysoberyl, topaz, beryl, garnet, quartz, garnet, barium sulfate, and glass.

[0468] The inorganic filler improves abrasion resistance, and mica is preferred for its aesthetic appeal. The particle size of the mica particles is 10 to 100 μm, preferably 15 to 50 μm. Particle sizes less than 10 μm tend to result in reduced abrasion resistance and reduced luster, while particles greater than 100 μm tend to result in reduced non-stick properties. Pigment-coated mica particles can be obtained by attaching a pigment such as TiO2·Fe2O3 to the mica particles using a sintering deposition method or the like.

[0469] Examples of metal flakes include flakes of titanium, zirconium, aluminum, zinc, antimony, tin, iron, nickel, etc., but titanium and zirconium are preferred from the viewpoint of rust resistance. The size of the flakes can be within the range of sizes normally used in paints.

[0470] Examples of metal powders include powders of gold, silver, copper, platinum, and stainless steel.

[0471] Various aqueous defoaming agents can be used, including lower alcohols such as methanol, ethanol, and butanol; higher alcohols such as amyl alcohol, polypropylene glycol, and its derivatives; oils and fats such as oleic acid, tall oil, mineral oil, and soap; surfactants such as sorbitan fatty acid esters, polyethylene glycol fatty acid esters, and Pluronic nonionic surfactants; and silicone surfactants such as siloxanes and silicone resins, which can be used alone or in combination. Representative commercially available defoaming agents include the B-series (manufactured by Asahi Denka Kogyo Co., Ltd.) such as Adekanate B and Adekanate B1068; the SN Deformer series (manufactured by Formaster DL, Nopco NXZ, and SN Deformer 113, 325, 308, and 368); Dehydran 1293 and Dehydran 1513 (manufactured by San Nopco Co., Ltd.); Flonone SB-110N, SB-210, 510, and 551; Aqualene 800 and 805. , Aqualene 1488 (manufactured by Kyoeisha Chemical Co., Ltd.); Surfynol 104E and 440 (acetylene-based defoamers manufactured by Air Products Co., Ltd.); KS-607A (manufactured by Shin-Etsu Chemical Co., Ltd.); FS Antifoam (manufactured by Dow Corning Corporation); BYK-020, 031, 073, and W (manufactured by BYK-Chemie); Dehydran 981 (manufactured by Henkel Hakusui Chemical Co., Ltd.); Epan-410, 710, and 720 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.); Tego Foamex series (manufactured by Tego Goldschmidt); and Foamrex-747, TY-10, and EP series (manufactured by Nicca Chemical Co., Ltd.). The content of the defoamer in the coating composition is preferably 0.01 to 10% by mass, and more preferably 0.05 to 5% by mass.

[0472] An example of the desiccant is cobalt oxide.

[0473] Examples of thickeners include methyl cellulose, polyvinyl alcohol, carboxylated vinyl polymers, etc. In the coating composition of the present disclosure, the content of the thickener is preferably 0.1 to 20.0 mass %, more preferably 0.5 to 10 mass %.

[0474] The organic solvent is preferably a high-boiling polyhydric alcohol, which can prevent mud cracks from occurring when the coating composition of the present disclosure is applied and then dried.

[0475] A high-boiling polyhydric alcohol (hereinafter referred to as "polyhydric alcohol") has two or more hydroxyl groups and a boiling point of 100°C or higher. Polyhydric alcohols containing nitrogen atoms are undesirable because they cause coloration due to thermal decomposition during baking. Preferably, the boiling point is at least the drying temperature of the coating composition, more preferably at least 150°C, and particularly at least 200°C. The preferred number of hydroxyl groups in a polyhydric alcohol is 2 to 3. Substances with one or no hydroxyl group and a boiling point of 100°C or higher have poor hydrophilicity, making uniform mixing difficult. Many polyhydric alcohols with four or more hydroxyl groups are solid at room temperature, making it difficult to expect mud crack prevention effects.

[0476] The polyhydric alcohol must ultimately evaporate or decompose and volatilize completely when heated during the baking process described below. Therefore, it is preferable that the boiling point or thermal decomposition temperature is equal to or lower than the melting point of the fluororesin or PTFE contained in the coating composition, preferably 340°C or lower.

[0477] Suitable polyhydric alcohols include, for example, one or more of ethylene glycol (boiling point: 198°C), 1,2-propanediol (boiling point: 188°C), 1,3-propanediol (boiling point: 214°C), 1,2-butanediol (boiling point: 190°C), 1,3-butanediol (boiling point: 208°C), 1,4-butanediol (boiling point: 229°C), 1,5-pentanediol (boiling point: 242°C), 2-butene-1,4-diol (boiling point: 235°C), glycerin (boiling point: 290°C), 2-ethyl-2-hydroxymethyl-1,3-propanediol (boiling point: 295°C), and 1,2,6-hexanetriol (boiling point: 178°C under 5 mmHg pressure). Among these, glycerin is preferred.

[0478] In the first coating composition of the present disclosure, the content of the polyhydric alcohol is generally 5 to 18 mass%, preferably 7 to 15 mass%, and particularly preferably 7 to 12 mass%, relative to the fluororesin. In the second coating composition and the third coating composition of the present disclosure, the content of the polyhydric alcohol is generally 5 to 18 mass%, preferably 7 to 15 mass%, and particularly preferably 7 to 12 mass%, relative to the PTFE. By keeping the polyhydric alcohol content within the above range, it is possible to prevent the occurrence of mud cracks while preventing discoloration of the resulting coating film.

[0479] If necessary, organic solvents other than the high-boiling polyhydric alcohols may be blended within a range that does not impair the effects of the present disclosure. Examples of such organic solvents include aromatic hydrocarbon solvents such as toluene and xylene, and aliphatic hydrocarbon solvents having 9 to 11 carbon atoms.

[0480] <Method of manufacturing the coating composition> The first coating composition of the present disclosure can be suitably produced, for example, by a production method including a step of polymerizing a fluoromonomer in an aqueous medium in the presence of polymer (I) to obtain a polymer dispersion containing a fluororesin, polymer (I), and an aqueous medium, and a step of concentrating the polymer dispersion by phase separation concentration to obtain a concentrated composition.

[0481] As a method for polymerizing a fluoromonomer in an aqueous medium in the presence of polymer (I), a conventionally known method can be adopted, for example, the method described in WO 2019 / 168183 or WO 2020 / 218620. Can be adopted.

[0482] The polymerization is preferably carried out in the absence of a fluorine-containing surfactant. In the present disclosure, "substantially in the absence of a fluorine-containing surfactant" means that the fluorine-containing surfactant is present in an amount of 10 ppm by mass or less, preferably 1 ppm by mass or less, more preferably 100 ppb by mass or less, even more preferably 10 ppb by mass or less, and still more preferably 1 ppb by mass or less, relative to the aqueous medium.

[0483] After obtaining a polymer dispersion containing a fluororesin, polymer (I), and an aqueous medium, the polymer dispersion is concentrated by phase separation concentration. By performing phase separation concentration, the content of polymer (I) in the coating composition of the present disclosure can be adjusted to the above-mentioned preferred range.

[0484] The concentration by phase separation can be carried out by heating a polymer dispersion containing a fluororesin, polymer (I), and an aqueous medium to cause phase separation into a fluororesin-free phase (supernatant phase) and a fluororesin-containing phase (concentrated phase), removing the fluororesin-free phase, and recovering the fluororesin-containing phase (concentrated phase).

[0485] Prior to the phase separation concentration, the polymer dispersion may be mixed with a nonionic surfactant to prepare a composition containing a fluororesin, polymer (I), a nonionic surfactant, and an aqueous medium, and the resulting composition may then be subjected to phase separation concentration. In this case, the phase separation concentration can be carried out by heating the composition to a temperature at least 10°C lower than the cloud point of the nonionic surfactant to cause phase separation into a supernatant phase and a concentrated phase, and recovering the concentrated phase to obtain a concentrated composition. The nonionic surfactant used in this step can be any of those described above, preferably at least one selected from the group consisting of nonionic surfactants represented by general formula (i) and nonionic surfactants represented by general formula (ii), with nonionic surfactants represented by general formula (i) being more preferred. Furthermore, polyoxyethylene alkyl ethers are suitable as nonionic surfactants.

[0486] The recovered fluororesin-containing phase (concentrated phase) contains the fluororesin and the aqueous medium, as well as the polymer (I) in a content reduced from that before concentration.

[0487] The concentration by phase separation may be carried out by leaving the mixture at a temperature that is 10°C lower than the cloud point of the nonionic surfactant or higher, or at a temperature that is 10°C higher than the cloud point or lower.

[0488] It is also preferable to repeatedly carry out the phase separation concentration. The number of repetitions is not particularly limited, but is preferably 2 or more times, more preferably 3 or more times. The upper limit of the number of repetitions is not limited, but may be, for example, 10 or less times. By repeatedly carrying out the phase separation concentration, the content of polymer (I) can be further reduced.

[0489] When phase separation concentration is performed two or more times, the first phase separation concentration is preferably performed by heating at a temperature at least 5°C lower than the cloud point of the nonionic surfactant, followed by standing to separate into an upper supernatant phase and a concentrated phase. The heating temperature is more preferably at least 3°C ​​lower than the cloud point, even more preferably at or above the cloud point, and particularly preferably heating above the cloud point. The second or subsequent phase separation concentration is preferably performed by heating at a temperature at least 5°C lower than the cloud point of the nonionic surfactant, followed by standing to separate into an upper supernatant phase and a concentrated phase. The heating temperature is more preferably at least 3°C ​​lower than the cloud point, and particularly preferably heating to the cloud point.

[0490] After the phase separation concentration, the concentrated composition may be mixed with an anionic hydrocarbon surfactant. By adding an anionic surfactant to the concentrated composition, it is possible to appropriately adjust the viscosity of the coating composition and improve the compatibility with pigments, fillers, etc., even when the coating composition contains a large amount of fluororesin.

[0491] After the phase separation concentration, a nonionic surfactant may be further added to the concentrated composition and mixed. By further adding a nonionic surfactant to the concentrated composition, the viscosity of the coating composition can be appropriately adjusted and the miscibility of pigments, fillers, etc. can be improved, even when the coating composition contains a large amount of fluororesin. The nonionic surfactant used in this case can be any of those described above, and is preferably at least one selected from the group consisting of nonionic surfactants represented by general formula (i) and nonionic surfactants represented by general formula (ii), with nonionic surfactants represented by general formula (i) being more preferred. Furthermore, polyoxyethylene alkyl ethers are suitable as nonionic surfactants.

[0492] A fluorine-containing compound having a hydrophilic group may be added to the polymer dispersion or the concentrated composition, but it is preferable not to add it to either of them.

[0493] The coating composition of the present disclosure can be produced by mixing the concentrated composition with components such as a film-forming agent, a binder resin, and other components that are added as needed. Alternatively, two or more aqueous dispersions may be produced by the above method and then mixed together. The method for mixing the components is not particularly limited, and any conventionally known method can be used. The order in which the components are mixed is also not particularly limited.

[0494] The second coating composition of the present disclosure can be suitably produced by a production method including the steps of: polymerizing TFE in an aqueous medium in the presence of polymer (I) to obtain a polymer dispersion containing PTFE, polymer (I), and an aqueous medium; and concentrating the polymer dispersion by performing phase separation concentration two or more times to obtain a concentrated composition. By such a production method, the second coating composition of the present disclosure, which has excellent aggregation suppression properties during stirring, can be obtained.

[0495] The step of obtaining a polymer dispersion can be configured as described above, except that in the step of obtaining a polymer dispersion containing a fluororesin, the polymer (I), and an aqueous medium by polymerizing a fluoromonomer in an aqueous medium in the presence of the polymer (I), TFE is used as the fluoromonomer and PTFE is obtained as the fluororesin.

[0496] The viscosity of the concentrated composition may be adjusted as necessary, for example, by mixing the concentrated composition with an anionic hydrocarbon surfactant, or by adding a nonionic surfactant to the concentrated composition and mixing them.

[0497] The third coating composition of the present disclosure can be suitably produced, for example, by a production method including the steps of: polymerizing TFE in an aqueous medium in the presence of polymer (I) containing polymerization units (I) based on a monomer represented by general formula (I) to obtain a polymerization dispersion containing PTFE, polymer (I), and an aqueous medium; mixing the polymerization dispersion with a nonionic surfactant to obtain a composition containing PTFE, polymer (I), nonionic surfactant, and an aqueous medium; concentrating the composition by phase separation concentration to obtain a concentrated composition; and adding an anionic hydrocarbon surfactant to the concentrated composition.

[0498] The step of obtaining a polymer dispersion can be configured as described above, except that in the step of obtaining a polymer dispersion containing a fluororesin, the polymer (I), and an aqueous medium by polymerizing a fluoromonomer in an aqueous medium in the presence of the polymer (I), TFE is used as the fluoromonomer and PTFE is obtained as the fluororesin.

[0499] As the anionic hydrocarbon surfactant, those mentioned above as the anionic hydrocarbon surfactant that can be contained in the third coating composition of the present disclosure can be suitably used.

[0500] The mixing ratio of the concentrated composition and the anionic hydrocarbon surfactant is not particularly limited, but it is preferable to mix the concentrated composition and the anionic hydrocarbon surfactant in a ratio that results in a suitable content of the anionic hydrocarbon surfactant in the third coating composition of the present disclosure.

[0501] When producing the third coating composition of the present disclosure, it is preferred that the polymerization is carried out in the absence of a fluorine-containing surfactant, and that no fluorine-containing compound having a hydrophilic group is added to the polymer dispersion or concentrated composition.

[0502] The coating composition of the present disclosure can be applied, for example, as a coating material for products whose substrate surfaces require heat resistance, non-stickiness, slipperiness, etc. Examples of products provided with such a coating material include the coated articles described below.

[0503] <Coating film> A coating film can be formed by applying the coating composition of the present disclosure to a substrate. The present disclosure also relates to a coating film obtained by applying the coating composition of the present disclosure.

[0504] The coating film of the present disclosure is obtained by applying the coating composition of the present disclosure, and therefore contains a fluororesin or PTFE.

[0505] The coating film of the present disclosure may contain, as needed, the components described above as other components in the coating composition of the present disclosure, such as binder resins, pigments, and inorganic fillers.

[0506] The coating film preferably has a thickness of 1 to 100 μm, more preferably 10 μm or more, and more preferably 50 μm or less.

[0507] The method for obtaining the coating film of the present disclosure is not particularly limited, and examples include methods for applying the coating composition of the present disclosure to a substrate by spray coating, roll coating, coating with a doctor blade, dip (immersion) coating, impregnation coating, spin flow coating, curtain flow coating, etc. Among these, spray coating is preferred.

[0508] After applying the coating composition of the present disclosure to a substrate, the coating composition is preferably dried and baked. Drying is preferably carried out at a temperature of 80 to 200°C for 5 to 30 minutes, and baking is preferably carried out at a temperature of 300 to 400°C for 10 to 90 minutes.

[0509] Letters, drawings, etc. may be printed on the coating film. The printing method is not particularly limited, and examples thereof include pad transfer printing. The printing ink used for printing is not particularly limited, and examples thereof include a composition comprising PES, a TFE homopolymer, and titanium oxide.

[0510] <Laminate> The present disclosure also relates to a laminate comprising the coating film of the present disclosure.

[0511] The laminate of the present disclosure preferably further includes a substrate. The coating film may be provided directly on the substrate, or may be provided on the substrate via another layer. Alternatively, another layer may be provided on the coating film.

[0512] It is also preferable that the laminate has two or more coating layers. For example, the laminate may have a substrate, a primer layer formed on the substrate, and a top coat layer formed on the primer layer. Alternatively, the laminate may have a substrate, a primer layer formed on the substrate, an intermediate layer formed on the primer layer, and a top coat layer formed on the intermediate layer. The intermediate layer may be two or more layers.

[0513] When the laminate has two or more coating films, at least one of the primer layer, intermediate layer, and top coat layer may be the coating film of the present disclosure. When the laminate has two or more coating films of the present disclosure, the two or more coating films may have the same composition or different compositions.

[0514] The laminate preferably further comprises layers other than the substrate and the coating film. These layers are usually provided between the substrate and the coating film.

[0515] The material of the substrate is not particularly limited, and examples thereof include metals such as iron, aluminum, stainless steel, copper, and alloys thereof, and non-metallic inorganic materials such as enamel, glass, ceramic, etc. Examples of alloys include stainless steel.

[0516] The substrate may be subjected to a surface treatment such as degreasing or roughening, as necessary. The roughening method is not particularly limited, and examples thereof include chemical etching with an acid or alkali, anodizing (anodizing), sandblasting, etc. The surface treatment may be appropriately selected depending on the type of substrate and primer coating composition, etc., from the viewpoints of enabling the primer coating composition for forming the primer layer to be uniformly applied without causing cissing and improving adhesion between the substrate and the primer layer, but sandblasting, for example, is preferred.

[0517] The substrate may be one that has been subjected to a degreasing treatment in which oil and other impurities are thermally decomposed and removed by baking at 380°C. In order to improve the adhesion between the substrate and the coating film, it is preferable to use an aluminum substrate that has been subjected to a surface roughening treatment using an alumina abrasive after surface treatment.

[0518] In one embodiment of the laminate of the present disclosure, the primer layer or the intermediate layer is the coating film of the present disclosure. When the primer layer or the intermediate layer is the coating film of the present disclosure, the top coat layer may be the coating film of the present disclosure or a coating film other than the coating film of the present disclosure.

[0519] In another embodiment of the laminate of the present disclosure, the top coat layer is the coating film of the present disclosure. When the top coat layer is the coating film of the present disclosure, the primer layer or the intermediate layer may be the coating film of the present disclosure or a coating film other than the coating film of the present disclosure.

[0520] The primer layer preferably contains a binder resin. Preferred binder resins are the same as the binder resins that can be contained in the coating composition of the present disclosure.

[0521] The content of the binder resin in the primer layer is preferably 10 to 50% by mass, more preferably 15% by mass or more, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0522] The primer layer may contain components other than the binder resin. The components other than the binder resin are not particularly limited, and examples thereof include fluororesins and the various components exemplified as other components. Preferred components other than the binder resin contained in the primer layer are fluororesins (particularly PTFE), pigments, and inorganic fillers.

[0523] The thickness of the primer layer is preferably 1 to 40 μm, and more preferably 5 to 35 μm. If the thickness is too thin, the anchoring effect of the primer surface cannot be expected, pinholes are likely to occur, and the corrosion resistance of the laminate may be reduced. If the thickness is too thick, coating defects such as cracks or blisters are likely to occur, and the abrasion resistance, hardness, and corrosion resistance of the laminate may be reduced. A more preferable upper limit of the thickness of the primer layer is 30 μm, and an especially preferable upper limit is 25 μm.

[0524] The primer layer can be obtained, for example, by applying a primer composition to a substrate, drying it as necessary, and then baking it. The method for applying the primer composition can be the same as the method for applying the coating composition of the present disclosure to a substrate. The drying and baking conditions for the primer composition can be the same as the conditions for drying and baking the coating composition of the present disclosure.

[0525] As the primer composition, a composition containing a binder resin and an aqueous medium is preferred, and a composition containing a binder resin, a fluororesin (particularly PTFE), and an aqueous medium is more preferred.

[0526] The intermediate layer preferably contains a fluororesin, such as PTFE or any of the fluororesins other than PTFE described above, with PTFE being preferred.

[0527] The content of the fluororesin is preferably 60 to 100% by mass, more preferably 65 to 100% by mass, and even more preferably 70 to 100% by mass, relative to the total mass of the intermediate layer. By using the fluororesin in the above range, it is possible to improve the adhesion between the intermediate layer and the coating film adjacent to the intermediate layer.

[0528] The intermediate layer may contain components other than the fluororesin. The components other than the fluororesin are not particularly limited, and for example, the additives exemplified as other components in the coating composition of the present disclosure can be used. The components other than the fluororesin contained in the intermediate layer are preferably a binder resin, a pigment, and an inorganic filler. The content of the inorganic filler is preferably 0.1 to 30% by mass of the intermediate layer, more preferably 20% by mass or less, and more preferably 1% by mass or more.

[0529] The thickness of the intermediate layer is preferably 5 to 30 μm, and more preferably 10 to 25 μm.

[0530] The intermediate layer can be obtained, for example, by applying an intermediate composition onto a primer layer and drying and baking as necessary. When there are two or more intermediate layers, the intermediate compositions for forming each intermediate layer can be applied in order and dried and baked as necessary to form two or more intermediate layers. As a method for applying the intermediate composition, the method described above as a method for applying the coating composition of the present disclosure onto a substrate can be used. As the drying and baking conditions for the intermediate composition, the conditions described above as the drying and baking conditions for the coating composition of the present disclosure can be used.

[0531] The intermediate composition is preferably a composition containing a fluororesin and an aqueous medium, and more preferably a composition containing a binder resin, a fluororesin and an aqueous medium.

[0532] The top coat layer preferably contains a fluororesin, more preferably PTFE. Suitable examples of the fluororesin and PTFE include those described above as the fluororesin and PTFE that can be contained in the coating composition of the present disclosure.

[0533] The content of the fluororesin is preferably 70 to 100% by mass, more preferably 75 to 100% by mass, and even more preferably 80 to 100% by mass, relative to the total mass of the top coat layer. By using the fluororesin in the above range, the non-stick properties of the top coat layer surface can be improved.

[0534] The top coat layer may contain a component other than the fluororesin. The component other than the fluororesin is not particularly limited, and for example, the additives exemplified as other components in the coating composition of the present disclosure can be used. As a component other than the fluororesin contained in the top coat layer, an inorganic filler is preferred.

[0535] The inorganic filler preferably has an average particle size of 14 μm or more. The average particle size of the inorganic filler is more preferably 16 μm or more, and even more preferably 20 μm or more. When the average particle size of the inorganic filler is within the above range, the abrasion resistance of the top coat layer can be improved. In order to further improve the abrasion resistance of the top coat layer, it is preferable that the inorganic filler protrudes from the top coat layer. The average particle size of the inorganic filler is calculated from the particle size distribution obtained by measurement using a laser diffraction / scattering particle size / particle size distribution analyzer (Microtrac MT3300II manufactured by Nikkiso Co., Ltd., medium: pure water, temperature: room temperature).

[0536] The amount of inorganic filler to be added can be adjusted depending on the type, hardness, etc. of the inorganic filler, but the abrasion resistance of the top coat layer can usually be improved by using it in the range of 2 to 10 mass % of the fluororesin.

[0537] The top coat layer preferably has a thickness of 10 to 40 μm. If the thickness is too thin, the non-stickiness, durability, and corrosion resistance of the resulting laminate may be insufficient. If the thickness is too thick, coating defects such as cracks and blisters are likely to occur. The lower limit of the thickness of the top coat layer is more preferably 15 μm or more, and even more preferably 18 μm or more. The upper limit is more preferably 30 μm or less, and even more preferably 25 μm or less.

[0538] The top coat layer can be obtained, for example, by applying a top coat composition to a primer layer or an intermediate layer, drying it as necessary, and then baking it. When the laminate of the present disclosure includes an intermediate layer, it is preferable to apply the intermediate composition to the primer layer, drying it as necessary, and then applying the top coat composition thereon, drying it as necessary, and baking it. This method allows the intermediate layer and the top coat layer to be baked simultaneously, resulting in excellent production efficiency. As a method for applying the top coat composition, the method described above as a method for applying the coating composition of the present disclosure to a substrate can be used. As the drying and baking conditions for the top coat composition, the conditions described above as the drying and baking conditions for the coating composition of the present disclosure can be used.

[0539] When the laminate of the present disclosure includes a top coat layer, letters, drawings, etc. may be printed on the top surface of the top coat layer.

[0540] <Painted items> The coating film of the present disclosure or the laminate of the present disclosure can also constitute a coated article. The present disclosure also relates to a coated article including the coating film of the present disclosure or the laminate of the present disclosure.

[0541] Examples of coated items include cooking utensils such as frying pans, grills, pressure cookers, other pots, rice cookers, rice cake makers, ovens, hot plates, bread molds, knives, and gas stoves; food and beverage containers such as electric kettles and ice trays; food industry parts such as kneading rolls, rolling rolls, conveyers, and hoppers; industrial products such as office automation equipment (OA) rolls, OA belts, OA separating claws, papermaking rolls, and film manufacturing calendar rolls; mold release parts for molding dies and molds for polystyrene foam, and release plates for plywood and decorative panel manufacturing; kitchen utensils such as range hoods; frozen food manufacturing equipment such as conveyor belts; tools such as saws, files, dies, and drills; household items such as irons, scissors, and knives; metal foil, electric wires; plain bearings for food processing machines, packaging machines, and textile machinery; sliding parts for cameras and watches; automotive parts such as pipes, valves, and bearings; snow shovels, plows, chutes, ship bottoms, boilers, and industrial containers (especially for the semiconductor industry).

[0542] 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. [Example]

[0543] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0544] The values ​​in the examples were measured by the following methods.

[0545] <Viscosity> Using a B-type viscometer (TVB-10 viscometer manufactured by Toki Sangyo), the liquid temperature of the coating composition (top coat coating composition or primer coating composition; the same applies below) was brought to 25°C, and then the viscosity was measured at 60 rpm using rotor No. 2, and the average value of two measurements was calculated to obtain the measured value.

[0546] <Solid content concentration of coating composition> 2 g of the coating composition was dried in a fan dryer at 100°C for 60 minutes, and then baked at 380°C for 45 minutes. The ratio of the mass of the heating residue to the mass of the coating composition (2 g) was expressed as a percentage and used as the value.

[0547] <Stability retention time> A 90 g sample was placed in a plastic cup with a diameter of 67 mm and a capacity of 300 ml, which was then immersed in a water bath at 60°C. A 50 mm diameter stirring blade (Figure 1) was set so that the height from the bottom of the plastic cup to the center of the stirring blade (6 mm from the bottom end of the stirring blade in the axial direction of Figure 1(b)) was 20 mm, and the cup was rotated at 3000 rpm. The time until the sample aggregated or solidified and scattered was measured as the stability retention time.

[0548] <Content of nonionic surfactant in aqueous dispersion> The content (N mass %) of the nonionic surfactant in the aqueous dispersion (either PTFE aqueous dispersions 1 to 3, A, or B, FEP aqueous dispersions A or B, or PFA aqueous dispersions A or B; the same applies below) was calculated from the formula: N = [(YZ) / Z] × 100 (mass %) by placing approximately 1 g (X g) of the sample in an aluminum cup with a diameter of 5 cm, heating it at 110°C for 30 minutes to obtain the heating residue (Y g), and further heating the obtained heating residue (Y g) at 300°C for 30 minutes to obtain the heating residue (Z g).

[0549] <Solid content concentration of aqueous dispersion> The solids concentration (P mass %) of the aqueous dispersion was calculated from the formula: P = [Z / X] × 100 (mass %) by placing approximately 1 g (X g) of the aqueous dispersion in an aluminum cup with a diameter of 5 cm, heating it at 110°C for 30 minutes to obtain the heating residue (Y g), and further heating the obtained heating residue (Y g) at 300°C for 30 minutes to obtain the heating residue (Z g).

[0550] <Content of Polymer A in Aqueous Dispersion> The content of polymer A in the aqueous dispersion relative to the fluororesin (PTFE, FEP, or PFA) (T AThe mass % was calculated using the following formula from the mass of water added to the reactor in the production example, the mass of polymer A, and the solids concentration of the obtained aqueous dispersion. T A =W D / [(W W ×P A / 100) / (1-P A / 100)]×100(mass%) W W : Mass of water added to the reactor W D : Mass of polymer A added to the reactor P A : Solids concentration of aqueous dispersion

[0551] <Content of Polymer A in the Upper Supernatant Phase> A predetermined amount of sodium trifluoroacetate was added to the upper supernatant phase, 19 F NMR measurement was carried out. From the peak area values ​​of sodium trifluoroacetate and polymer A, the content of polymer A in the upper supernatant phase (T S The mass % was calculated.

[0552] <Content of Polymer A in Aqueous Dispersion> The content of polymer A relative to the fluororesin (PTFE, FEP, or PFA) in the aqueous dispersion (T D The mass % was calculated using the following formula. T D =T A -W S ×T2 / W A T A (mass%): content of polymer A in the aqueous dispersion relative to the fluororesin T S (mass%): Content of polymer A in the supernatant phase W S (g): Mass of the upper supernatant phase W A (g): Mass of fluororesin in aqueous dispersion before concentration (i.e., the mass of the fluororesin in the concentrated phase)

[0553] <Average primary particle diameter> The PTFE aqueous dispersion A was diluted with water to a solid content of 0.15% by mass, and the transmittance of the 550 nm incident light per unit length of the diluted latex obtained and the number-average primary particle diameter determined by measuring the unidirectional diameter using a transmission electron microscope photograph were measured to prepare a calibration curve. Using this calibration curve, the average primary particle diameter was determined from the measured transmittance of the 550 nm incident light of each sample.

[0554] <Standard specific gravity (SSG)> Using samples molded in accordance with ASTM D 4895-89, measurements were made by the water displacement method in accordance with ASTM D 792.

[0555] <Fluorine-containing surfactant content> An amount of aqueous dispersion equivalent to 1.5 g of fluororesin solids in the aqueous dispersion was weighed into a 100 mL screw tube. This was then combined with the water contained in the aqueous dispersion, and water and methanol were added so that the extraction solvent was 37 g of water / methanol = 10 / 90 mass%, and the mixture was shaken vigorously until coagulation occurred. The liquid phase was removed and centrifuged at 4000 rpm for 1 hour to extract the supernatant. The fluorosurfactants in the extract were measured using a liquid chromatograph mass spectrometer (Waters, LC-MS ACQUITY UPLC / TQD). The measurement instrument configuration and LC-MS measurement conditions are shown in Table 1.

[0556] [Table 1]

[0557] The calibration curve used to calculate the concentration of the fluorine-containing surfactant was obtained under the following conditions. Five standard methanol solutions of fluorine-containing surfactants with known concentrations ranging from 1 ng / mL to 100 ng / mL were prepared and measured using a liquid chromatograph mass spectrometer (Waters, LC-MS ACQUITY UPLC / TQD). Using a first-order approximation from the respective sample concentrations and peak integral values, a and b were calculated using the following relational equation (3). A=a×X+b (3) A: Peak area of ​​fluorine-containing surfactant X: Concentration of fluorine-containing surfactant (ng / mL) The lower limit of quantification is 100 ppb.

[0558] The surfactants used in the preparation examples are as follows: Surfactant (a): Polyoxyethylene alkyl ether (C 13 H 27 -(C2H4O) n -H)(cloud point 60℃)

[0559] <Polymer A> A homopolymer of monomer A (number average molecular weight: 140,000, weight average molecular weight: 180,000) (hereinafter referred to as polymer A) represented by the formula: CH2=CF(CF2OCFCF3COONH4) was used. The number-average molecular weight and weight-average molecular weight were measured by gel permeation chromatography (GPC) using a Tosoh GPC HLC-8020 column and Shodex columns (one GPC KF-801, one GPC KF-802, and two GPC KF-806M columns connected in series) using tetrahydrofuran (THF) as the solvent at a flow rate of 1 ml / min, and the molecular weight was calculated using monodisperse polystyrene as the standard.

[0560] Preparation Example 1 (Preparation of PTFE Aqueous Dispersion A) A 6 L stainless steel reactor equipped with a stirrer was charged with 3448 g of deionized water, 180 g of paraffin wax, and 103 g of a 5.0 wt% aqueous solution of Polymer A. Ammonia water was added to adjust the pH to 8.7. The reactor contents were then heated to 70 °C while evacuating and simultaneously purging with TFE to remove oxygen from the reactor, and the contents were stirred. 2.4 g of HFP and 0.01 g of isopropyl alcohol were added to the reactor, followed by TFE addition until the pressure reached 0.73 MPaG. 25.1 mg of ammonium persulfate (APS) and 537 mg of disuccinic acid peroxide (DSP) dissolved in 20 g of deionized water were added, and the reactor pressure was adjusted to 0.83 MPaG. A total of 3580 g of water was added to the reactor. After the initiator was added, a pressure drop occurred, and the initiation of polymerization was observed. TFE was added to the reactor to maintain a constant pressure of 0.78 MPaG. When the amount of TFE consumed in the reaction reached approximately 180 g, the supply of TFE and stirring were stopped. The gas in the reactor was then slowly released until the reactor pressure reached 0.02 MPaG. TFE was then supplied until the reactor pressure reached 0.78 MPaG, and stirring was resumed to continue the reaction. When the amount of TFE consumed in the reaction reached approximately 1,470 g, the supply of TFE was stopped, stirring was stopped, and the reaction was terminated. The reactor was then vented until the pressure inside reached atmospheric pressure, and the contents were removed from the reactor and cooled. The supernatant paraffin wax was removed to obtain PTFE aqueous dispersion 1.

[0561] The solid content of the PTFE aqueous dispersion 1 was 29.1% by mass, and the average primary particle size was 250 nm. The concentration of polymer A in the PTFE aqueous dispersion 1 was 0.35% by mass.

[0562] PTFE aqueous dispersion 1 was diluted with deionized water to a solids concentration of approximately 10% by mass, coagulated under high-speed stirring conditions, and the resulting wet powder was dried for 18 hours at 210° C. The SSG of the resulting PTFE powder was 2.201.

[0563] To PTFE aqueous dispersion 1, 15 parts by mass of surfactant (a) was added per 100 parts by mass of PTFE, and then water was added to adjust the solids concentration to 25%, followed by heating in a constant-temperature water bath at 62°C. After confirming that the contents had reached 62°C, the mixture was allowed to stand and concentration was initiated, at which point phase separation began (separation into an upper supernatant phase and a concentrated phase). Heating was terminated 360 minutes after the start of concentration, and the upper supernatant phase and concentrated phase were recovered to obtain upper supernatant phase 1 and PTFE aqueous dispersion 2, respectively. The solids concentration of the resulting PTFE aqueous dispersion 2 was 62%, and the surfactant (a) content was 3.5% by mass relative to PTFE. The content of polymer A in the resulting upper supernatant phase 1 was 0.10% by mass relative to the upper supernatant phase.

[0564] To the obtained PTFE aqueous dispersion 2, surfactant (a) was added so that the amount was 5.5 mass % relative to PTFE, and ammonium lauryl sulfate was further added in an amount of 2000 ppm relative to PTFE, and deionized water and aqueous ammonia were further added to obtain PTFE aqueous dispersion A.

[0565] The resulting PTFE aqueous dispersion A had a solids concentration of 60.0 mass %, and the content of surfactant (a) was 5.5 mass % relative to PTFE. The content of polymer A in the resulting PTFE aqueous dispersion A was 0.12 mass % relative to PTFE and 0.072 mass % relative to the PTFE aqueous dispersion.

[0566] Approximately 5 g of a sample of PTFE aqueous dispersion A was weighed, 10 ml of methanol was added, and the sample was poured into a cylindrical filter paper. Soxhlet extraction was performed so that the total amount of methanol used as the extraction solvent became 100 ml. The resulting extract was concentrated with an appropriate nitrogen purge to obtain an extract. The resulting extract was subjected to LC / MS measurement. The detection limit in the measurement was 5 ppb by mass. Fluorine-containing compounds with hydrophilic groups, including all compounds represented by the following formulas, were not detected. F(CF2)7COOM, F(CF2)5COOM, H(CF2)6COOM, H(CF2)7COOM, CF3O(CF2)3OCHFCF2COOM, C3F7OCF(CF3)CF2OCF(CF3)COOM, CF3CF2CF2OCF(CF3)COOM, CF3CF2OCF2CF2OCF2COOM, C2F5OCF(CF3)CF2OCF(CF3)COOM, CF3OCF(CF3)CF2OCF(CF3)COOM, CF2ClCF2CF2OCF(CF3)CF2OCF2COOM, CF2ClCF2CF2OCF2CF(CF3)OCF2COOM, CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM, CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM, [ka] (In each formula, M is H, metal atom, NR 7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0567] Preparation Example 2 (Preparation of FEP Aqueous Dispersion A) An FEP aqueous dispersion was obtained in accordance with Example 24 of WO 2019 / 168183. Phase separation and concentration were carried out in the same manner as in Preparation Example 1 to obtain FEP aqueous dispersion A. The solids concentration of the obtained FEP aqueous dispersion A was 54% by mass.

[0568] Preparation Example 3 (Preparation of PFA aqueous dispersion A) A PFA aqueous dispersion was obtained in accordance with Example 22 of WO 2019 / 168183. Phase separation and concentration were carried out in the same manner as in Preparation Example 1 to obtain a PFA aqueous dispersion A. The solid content concentration of the obtained PFA aqueous dispersion A was 50% by mass.

[0569] Synthesis Example 1 After purging the air in a 1-L autoclave with nitrogen, 16.5 g of dehydrated tetramethylurea and 220 g of diethylene glycol dimethyl ether were charged and cooled. 38.5 g of carbonyl fluoride was charged, followed by 100 g of hexafluoropropylene oxide, which was then stirred. Subsequently, 38.5 g of carbonyl fluoride and 100 g of hexafluoropropylene oxide were additionally charged. Then, equal amounts of carbonyl fluoride and hexafluoropropylene oxide were further charged. After completion of the reaction, the reaction mixture was removed and separated to obtain the lower layer reaction product.

[0570] A 6-L autoclave was charged with 1,000 ml of tetraglyme and 75 g of CsF, and the atmosphere inside the autoclave was replaced with nitrogen. The autoclave was then cooled, and 2,100 g of the reaction product obtained above was charged. Hexafluoropropylene oxide was then introduced into the autoclave to initiate the reaction. Finally, 1,510 g of hexafluoropropylene oxide was charged. The contents were then removed, and the upper and lower layers were separated using a separatory funnel. The upper layer weighed 1,320 g, and the lower layer weighed 3,290 g. The lower layer was rectified and isolated.

[0571] Next, 1000 g of purified water was added to 1000 g of the isolated target product to carry out hydrolysis. The liquids were then separated using a separatory funnel, and the organic layer (lower layer) was collected. The collected solution was washed with aqueous sulfuric acid. The resulting solution was then purified by simple distillation. After purification, 500 g of the above-obtained simple distillate was added dropwise to an aqueous solution prepared by mixing the obtained compound, 76 g of 28 wt % aqueous ammonia solution, and 600 g of purified water. After the dropwise addition, 28 wt % aqueous ammonia solution was added to adjust the pH to 7. This was then freeze-dried to obtain the ammonium salt of perfluoroethercarboxylic acid A.

[0572] Preparation Example 4 (Preparation of PTFE Aqueous Dispersion B) Using the ammonium salt of perfluoroethercarboxylic acid A, a PTFE aqueous dispersion B was obtained by a known emulsion polymerization method, a known ion exchange treatment method, and a known phase separation concentration method. The obtained PTFE aqueous dispersion had a solids concentration of 60 mass% and a standard specific gravity of 2.200. The fluorine-containing surfactant (perfluoroethercarboxylic acid A) content of the PTFE aqueous dispersion B was 650 ppb.

[0573] Preparation Example 5 (Preparation of FEP Aqueous Dispersion B) Using the ammonium salt of perfluoroethercarboxylic acid A, a known emulsion polymerization method, a known ion exchange treatment method, and a known phase separation concentration method were used to obtain an FEP aqueous dispersion B. The obtained FEP aqueous dispersion had a solids concentration of 54 mass% and an MFR of 5 g / 10 min.

[0574] Preparation Example 6 (Preparation of PFA aqueous dispersion B) Using the ammonium salt of perfluoroethercarboxylic acid A, a known emulsion polymerization method, a known ion exchange treatment method, and a known phase separation concentration method was used to obtain a PFA aqueous dispersion B. The obtained PFA aqueous dispersion had a solids concentration of 50 mass% and an MFR of 29 g / 10 min.

[0575] In each of the examples and comparative examples, the following materials were used. Depolymerizable acrylic resin emulsion: butyl methacrylate resin, average particle size 0.3 μm, butyl methacrylate resin content 40% by mass 50% by mass aqueous solution of nonionic surfactant: 50% by mass aqueous solution of polyoxyethylene alkyl ether Hydrocarbon solvent: A mixture of C10-12 aliphatic saturated hydrocarbons Polyimideamide resin aqueous dispersion: Aqueous dispersion of polyamideimide resin varnish prepared in accordance with the examples described in JP 2015-127142 A Carbon black pigment mill base (solids concentration 20% by mass): A water-based black pigment paste prepared by grinding commercially available carbon black pigment (average particle size 100 nm or less) with a nonionic surfactant and water using a sand mill and glass beads as dispersion media. Thickener: Methylcellulose Leveling agent: acetylene glycol

[0576] Example 1 The following components were stirred and mixed to obtain a top coat paint composition. PTFE aqueous dispersion A (solid content concentration 60% by mass) 70.0 parts Depolymerizable acrylic resin emulsion 12.6 parts 7.9 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.1 parts glycerin Hydrocarbon solvent 1.3 parts Water 5.1 parts The contents of polymer (I), fluororesin, nonionic surfactant, and ammonium lauryl sulfate in the obtained top coat paint composition were calculated from the blend amounts of each material. The viscosity, solids concentration, and stability retention time of the obtained top coat paint composition were also measured. The results are shown in Table 2. The content of polymer A was 504 ppm by mass.

[0577] Example 2 The following components were stirred and mixed to obtain a top coat paint composition. PTFE aqueous dispersion A (solid content concentration 60% by mass) 67.0 parts FEP aqueous dispersion A (solid content concentration 54% by mass) 3.0 parts Depolymerizable acrylic resin emulsion 12.6 parts 7.9 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.1 parts glycerin Hydrocarbon solvent 1.3 parts Water 5.1 parts The obtained top coat paint composition was subjected to calculations and measurements in the same manner as in Example 1. The results are shown in Table 2.

[0578] Example 3 The following components were stirred and mixed to obtain a top coat paint composition. PTFE aqueous dispersion A (solid content concentration 60% by mass) 67.0 parts PFA aqueous dispersion A (solid content concentration 50% by mass) 3.0 parts Depolymerizable acrylic resin emulsion 12.6 parts 7.9 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.1 parts glycerin Hydrocarbon solvent 1.3 parts Water 5.1 parts The obtained top coat paint composition was subjected to calculations and measurements in the same manner as in Example 1. The results are shown in Table 2.

[0579] Example 4 The following components were stirred and mixed to obtain a top coat paint composition. FEP aqueous dispersion A (solid content concentration 54% by mass) 78.0 parts 7.9 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.1 parts glycerin Hydrocarbon solvent 1.3 parts Water 9.7 parts The obtained top coat paint composition was subjected to calculations and measurements in the same manner as in Example 1. The results are shown in Table 2.

[0580] Example 5 The following components were stirred and mixed to obtain a top coat paint composition. PFA aqueous dispersion A (solid content concentration 50% by mass) 84.0 parts 7.9 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.1 parts glycerin Hydrocarbon solvent 1.3 parts Water 3.7 parts The obtained top coat paint composition was subjected to calculations and measurements in the same manner as in Example 1. The results are shown in Table 2.

[0581] Comparative Example 1 A top coat paint composition was obtained in the same manner as in Example 1, except that 70.0 parts of PTFE aqueous dispersion B was used instead of 70.0 parts of PTFE aqueous dispersion A. For the obtained top coat paint composition, calculations and measurements were carried out in the same manner as in Example 1. The results are shown in Table 2. The content of perfluoroethercarboxylic acid A in the obtained top coat paint composition was 455 ppb.

[0582] Comparative Example 2 A top coat paint composition was obtained in the same manner as in Comparative Example 1, except that the amount of PTFE aqueous dispersion B added was changed from 70.0 parts to 67.0 parts, and 3.0 parts of FEP aqueous dispersion B was further added. Calculations and measurements were performed on the obtained top coat paint composition in the same manner as in Example 1. The results are shown in Table 2.

[0583] Comparative Example 3 A top coat paint composition was obtained in the same manner as in Comparative Example 1, except that the amount of PTFE aqueous dispersion B added was changed from 70.0 parts to 67.0 parts, and 3.0 parts of PFA aqueous dispersion B was further added. Calculations and measurements were performed on the obtained top coat paint composition in the same manner as in Example 1. The results are shown in Table 2.

[0584] [Table 2]

[0585] Example 6 The following components were stirred and mixed to obtain a primer coating composition. PTFE aqueous dispersion A (solid content concentration 60% by mass) 40.0 parts Polyamideimide resin aqueous dispersion 39.0 parts 8.0 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.6 parts carbon black pigment mill base (solids concentration 20% by mass) Thickener 7.0 parts Leveling agent 1.0 parts 1.4 parts water The resulting primer coating composition was subjected to calculations and measurements in the same manner as in Example 1. The results are shown in Table 3. The content of polymer A was 288 ppm by mass.

[0586] Example 7 The following components were stirred and mixed to obtain a primer coating composition. PTFE aqueous dispersion A (solid content concentration 60% by mass) 36.0 parts FEP aqueous dispersion A (solid content 54% by mass) 4.0 parts Polyamideimide resin aqueous dispersion 39.0 parts 8.0 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.6 parts carbon black pigment mill base (solids concentration 20% by mass) Thickener 7.0 parts Leveling agent 1.0 parts 1.4 parts water The resulting primer coating composition was subjected to calculations and measurements in the same manner as in Example 1. The results are shown in Table 3.

[0587] Example 8 The following components were stirred and mixed to obtain a primer coating composition. PTFE aqueous dispersion A (solid content concentration 60% by mass) 27.0 parts FEP aqueous dispersion A (solid content concentration 54% by mass) 13.0 parts Polyamideimide resin aqueous dispersion 39.0 parts 8.0 parts of a 50% by weight aqueous solution of a nonionic surfactant 3.6 parts carbon black pigment mill base (solids concentration 20% by mass) Thickener 7.0 parts Leveling agent 1.0 parts 1.4 parts water The resulting primer coating composition was subjected to calculations and measurements in the same manner as in Example 1. The results are shown in Table 3.

[0588] Comparative Example 4 A primer coating composition was obtained in the same manner as in Example 6, except that 40.0 parts of PTFE aqueous dispersion B was used instead of 40.0 parts of PTFE aqueous dispersion A. For the obtained primer coating composition, calculations and measurements were carried out in the same manner as in Example 1. The results are shown in Table 3. The content of perfluoroether carboxylic acid A in the obtained primer coating composition was 260 ppb.

[0589] Comparative Example 5 A primer coating composition was obtained in the same manner as in Comparative Example 4, except that the amount of PTFE aqueous dispersion B added was changed from 40.0 parts to 36.0 parts, and 4.0 parts of FEP aqueous dispersion B was added. Calculations and measurements were carried out on the obtained primer coating composition in the same manner as in Example 1. The results are shown in Table 3.

[0590] Comparative Example 6 A primer coating composition was obtained in the same manner as in Comparative Example 4, except that the amount of PTFE aqueous dispersion B added was changed from 40.0 parts to 27.0 parts, and 13.0 parts of FEP aqueous dispersion B was added. Calculations and measurements were carried out on the obtained primer coating composition in the same manner as in Example 1. The results are shown in Table 3.

[0591] [Table 3]

Claims

1. A coating composition comprising a fluororesin, a polymer (I) containing polymerized units (I) based on a monomer represented by general formula (I), and an aqueous medium, A coating composition, wherein the content of the polymer (I) is 2000 mass ppm or less relative to the coating composition. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

2. 2. The coating composition according to claim 1, having a viscosity of 100 mPa·s or more and 1000 mPa·s or less.

3. 3. The coating composition according to claim 1, wherein the content of the fluororesin is 15.0% by mass or more and 52.0% by mass or less based on the coating composition.

4. The coating composition according to any one of claims 1 to 3, wherein the fluororesin is at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, ethylene / tetrafluoroethylene copolymer, and ethylene / chlorotrifluoroethylene copolymer.

5. 5. The coating composition according to claim 1, wherein the stability retention time measured by a stirring test is 10 minutes or more.

6. 6. The coating composition according to claim 1, wherein the content of the polymer (I) is 0.1 ppm by mass or more based on the coating composition.

7. The coating composition according to any one of claims 1 to 6, further comprising a nonionic surfactant.

8. A coating composition comprising a fluororesin, a polymer (I) containing polymerized units (I) based on a monomer represented by general formula (I), and an aqueous medium, The content of the polymer (I) is 2000 ppm by mass or less relative to the coating composition, The stability retention time measured by the stirring test is 10 minutes or more, A coating composition having a viscosity of 50 mPa·s or more and 1000 mPa·s or less. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

9. 9. The coating composition according to claim 8, wherein the content of the fluororesin is 15.0% by mass or more and 52.0% by mass or less based on the coating composition.

10. 10. The coating composition according to claim 8, wherein the fluororesin contains at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, and tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer.

11. 10. The coating composition according to claim 8, wherein the fluororesin contains at least polytetrafluoroethylene.

12. 12. The coating composition according to claim 11, wherein the content of polytetrafluoroethylene in the coating composition is 60 mass % or more relative to the fluororesin.

13. 10. The coating composition according to claim 8, wherein the fluororesin is a tetrafluoroethylene / hexafluoropropylene copolymer alone, and the content of the fluororesin is 30.0 mass% or more and 50.0 mass% or less relative to the coating composition.

14. 10. The coating composition according to claim 8 or 9, wherein the fluororesin comprises only a tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer, and the content of the fluororesin is 30.0 mass% or more and 50.0 mass% or less relative to the coating composition.

15. A coating composition comprising a fluororesin, a polymer (I) containing polymerized units (I) based on a monomer represented by general formula (I), a nonionic surfactant, an anionic hydrocarbon surfactant, and an aqueous medium, The content of the polymer (I) is 2000 ppm by mass or less relative to the coating composition, A coating composition that is substantially free of fluorine-containing compounds that have hydrophilic groups. CX １ X ３ =CX ２ R(-CZ １ Z ２ -A ０ ) ｍ (I) (In the formula, X １ and X ３ are each independently F, Cl, H or CF ３ and X ２ is H, F, an alkyl group or a fluorine-containing alkyl group; A ０ is an anionic group; R is a linking group; Z １ and Z ２ are each independently H, F, an alkyl group or a fluorine-containing alkyl group; and m is an integer of 1 or more.

16. 16. The coating composition according to claim 15, wherein the fluorine-containing compound having a hydrophilic group is an anionic fluorine-containing surfactant containing fluorine in the anionic moiety having a molecular weight of 800 or less.

17. 17. The coating composition according to claim 15, wherein the content of the fluorine-containing compound having a hydrophilic group is 100 ppb by mass or less.

18. The fluorine-containing compound having a hydrophilic group is H(CF ２ ) ７ COOM F(CF ２ ) ７ COOM、 F(CF ２ ) ５ COOM、 H(CF ２ ) ６ COOM、 CF ３ O(CF ２ ) ３ OCHFCF ２ AOM、 C ３ F ７ OCF(CF ３ )CF ２ OCF(CF ３ )COOM、 CF ３ CF ２ CF ２ OCF(CF ３ )COOM、 CF ３ CF ２ OCF ２ CF ２ OCF ２ COOM、 C ２ F ５ OCF(CF ３ )CF ２ OCF(CF ３ )COOM、 CF ３ OCF(CF ３ )CF ２ OCF(CF ３ )COOM、 CF ２ ClCF ２ CF ２ OCF(CF ３ )CF ２ OCF ２ COOM、 CF ２ ClCF ２ CF ２ OCF ２ CF(CF ３ )OCF ２ COOM、 CF ２ ClCF(CF ３ )OCF(CF ３ )CF ２ OCF ２ COOM、 CF ２ ClCF(CF ３ ) OCF ２ CF (CF ３ ) OCF ２ COOM, and 【Chemistry 30】 (In each formula, M is H, metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ７ The coating composition according to any one of claims 15 to 17, wherein the compound is represented by the formula:

19. The coating composition according to any one of claims 15 to 18, wherein the content of the fluororesin is 15.0 mass% or more and 52.0 mass% or less relative to the coating composition.

20. The coating composition according to any one of claims 15 to 19, wherein the fluororesin contains at least one selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, and tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymer.

21. The coating composition according to any one of claims 15 to 19, wherein the fluororesin contains at least polytetrafluoroethylene.

22. 22. The coating composition according to claim 21, wherein the content of polytetrafluoroethylene in the coating composition is 60 mass % or more relative to the fluororesin.

23. The coating composition according to any one of claims 1 to 22, further comprising a film-forming agent.

24. The coating composition according to any one of claims 1 to 23, further comprising a binder resin, wherein the binder resin is at least one selected from the group consisting of polyamideimide, polyimide, polyethersulfone, and polyphenylene sulfide.

25. A coating film obtained by applying the coating composition according to any one of claims 1 to 24.

26. A laminate comprising the coating film according to claim 25.

27. A coated article comprising the coating film according to claim 25 or the laminate according to claim 26.

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