CN116057135A - Coating compositions and coatings - Google Patents

Abstract

The present invention provides a coating composition and the like which can obtain a coating film with excellent non-adhesiveness and persistence. A coating composition comprising a heat-resistant binder resin, a heat-fusible fluororesin and an organic solvent, wherein the heat-fusible fluororesin is a powder having an average particle diameter of 1.0 [ mu ] m or less, has a melting point of 270 ℃ or more, and has a melt flow rate of 15 to 45g/10 minutes, and the heat-fusible fluororesin is 10 to 200 parts by mass relative to 100 parts by mass of the heat-resistant binder resin.

Description

Coating composition and coated product

Technical Field

The present disclosure relates to coating compositions and coated products.

Background Art

Heat resistance and non-stick properties are required for frying pans, gas range tops, microwave oven inner wall materials, etc.

Patent Document 1 describes a coating composition containing a polyethersulfone resin, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer having a specific melting point and average particle size, and a specific organic solvent in a specific ratio.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2000-026786

Summary of the invention

Problems to be solved by the invention

An object of the present disclosure is to provide a coating composition capable of obtaining a coating film having excellent non-stickiness and durability, and a coated product having excellent non-stickiness and durability.

Means for solving problems

The present disclosure relates to a coating composition comprising a heat-resistant binder resin, a hot-melt fluororesin and an organic solvent, wherein the hot-melt fluororesin is a powder having an average particle size of 1.0 μm or less, a melting point of 270° C. or higher, and a melt flow rate of 15 to 45 g/10 minutes, and the hot-melt fluororesin is 10 to 200 parts by mass relative to 100 parts by mass of the heat-resistant binder resin.

The present disclosure also relates to a coated product including a substrate and a coating film, wherein the coating film is provided on the substrate and is formed from the coating composition.

Effects of the Invention

According to the present disclosure, it is possible to provide a coating composition capable of obtaining a coating film having excellent non-stickiness and durability, and a coated product having excellent non-stickiness and durability.

DETAILED DESCRIPTION

The present disclosure is described in detail below.

The present disclosure relates to a coating composition comprising a heat-resistant binder resin, a hot-melt fluororesin and an organic solvent, wherein the hot-melt fluororesin is a powder having an average particle size of 1.0 μm or less, a melting point of 270° C. or more, and a melt flow rate of 15 to 45 g/10 minutes, and the hot-melt fluororesin is 10 to 200 parts by mass relative to 100 parts by mass of the heat-resistant binder resin.

The coating composition of the present disclosure can provide a coating film having excellent non-adhesive durability.

The coating composition of the present disclosure can also provide a coating film having excellent surface smoothness.

The coating composition of the present disclosure includes a heat-resistant binder resin.

The heat-resistant binder resin may be any resin generally recognized to have heat resistance, but does not include fluorine-containing polymers. In this specification, "heat resistance" means a property that allows continuous use at a temperature of 150° C. or higher.

Examples of the heat-resistant binder resin include polyamideimide resin (PAI), polyimide resin (PI), polyethersulfone resin (PES), polyetherimide resin (PEI), aromatic polyetherketone resin, aromatic polyester resin, and polyarylene sulfide resin. One type may be used alone, or two or more types may be used in combination.

PAI is a resin composed of a polymer having an amide bond and an imide bond in the molecular structure. The PAI is not particularly limited, and examples thereof include resins composed of high molecular weight polymers obtained by the following reactions: reaction of an aromatic diamine having an amide bond in the molecule with an aromatic tetracarboxylic acid such as pyromellitic acid; 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; reaction of a dibasic acid having an aromatic imide ring in the molecule with a diamine; and the like. From the perspective of excellent heat resistance, the PAI is preferably composed of a polymer having an aromatic ring in the main chain.

PI is a resin composed of a polymer having an imide bond in its molecular structure. The PI is not particularly limited, and examples thereof include resins composed of high molecular weight polymers obtained by reaction of aromatic tetracarboxylic anhydrides such as pyromellitic dianhydride, etc. From the perspective of excellent heat resistance, the PI is preferably composed of a polymer having an aromatic ring in the main chain.

PES has the following general formula:

[Chemistry 1]

The PES is not particularly limited, and examples thereof include a resin composed of a polymer obtained by polycondensation of dichlorodiphenyl sulfone and bisphenol.

The aromatic polyetherketone resin is a resin containing repeating units composed of an arylene group, an ether group [-O-], and a carbonyl group [-C(=O)-]. Examples of the aromatic polyetherketone resin include polyetherketone resin (PEK), polyetheretherketone resin (PEEK), polyetheretherketoneketone resin (PEEKK), and polyetherketone ester resin. The aromatic polyetherketone resin can be used alone or in combination of two or more.

The aromatic polyetherketone resin is preferably at least one selected from the group consisting of PEK, PEEK, PEEKK and polyetherketone ester resins, and more preferably PEEK.

The heat-resistant binder resin preferably comprises at least one selected from the group consisting of PAI, PI, PEI and PES. Thus, a coating film having more excellent non-adhesive persistence and surface smoothness can be obtained. In addition, the coating film has excellent adhesion to the substrate, and has sufficient heat resistance even at the temperature when firing when forming the coating film, and the corrosion resistance and water vapor resistance of the obtained coating film are excellent.

Among the above-mentioned heat-resistant binder resins, in addition to the above-mentioned effects, it is more preferable to contain PES from the viewpoint of the degree of freedom in coloring and processability.

The coating composition of the present disclosure contains a hot-melt fluororesin.

The melt flow rate (MFR) of the hot-melt fluororesin is 15 to 45 g/10 minutes. If the MFR is too low, the non-stickiness and surface smoothness may be deteriorated; if the MFR is too high, the non-stickiness may be deteriorated.

The MFR is preferably 20 g/10 min or more, more preferably 25 g/10 min or more, and preferably 40 g/10 min or less, more preferably 35 g/10 min or less.

The above-mentioned MFR is a value obtained as follows: in accordance with ASTM D 1238, using a melt flow indexer (manufactured by Yasuda Seiki Seisakusho), the mass (g/10 minutes) of the polymer flowing out from a nozzle having an inner diameter of 2 mm and a length of 8 mm is measured at a measurement temperature (for example, 372° C. in the case of PFA and FEP, and 297° C. in the case of ETFE) and a load (for example, 5 kg in the case of PFA, FEP and ETFE) determined according to the type of fluoropolymer, and the obtained value is taken as MFR.

The melting point of the heat-meltable fluororesin is 270° C. or higher. From the viewpoint of heat resistance and antifouling properties, the melting point is preferably 270 to 330° C. From the viewpoint of heat resistance and film-forming properties of the heat-meltable fluororesin during processing, the melting point is more preferably 280 to 320° C.

The melting point is the peak temperature of an endothermic curve obtained by thermal measurement at a heating rate of 10° C./min using a differential scanning calorimeter in accordance with ASTM D-4591.

As the above-mentioned hot-melt fluororesin, at least one selected from the group consisting of tetrafluoroethylene (TFE)/perfluoro(alkyl vinyl ether) (PAVE) copolymer (PFA), TFE/hexafluoropropylene (HFP) copolymer (FEP), ethylene (Et)/TFE copolymer (ETFE), Et/TFE/HFP copolymer, polychlorotrifluoroethylene (PCTFE), CTFE/TFE copolymer, Et/CTFE copolymer and polyvinylidene fluoride (PVDF) can be cited.

From the viewpoint of obtaining a coating film having more excellent non-stickiness and surface smoothness, the hot-melt fluororesin is preferably at least one selected from the group consisting of PFA and FEP, and from the viewpoint of the above-mentioned effects and heat resistance, PFA is more preferable.

As PAVE in the above PFA, for example, the formula (1) can be cited:

CF ₂ =CF-ORf ¹ (1)

(wherein ^Rf1 represents a perfluoroalkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms), among which perfluoro(methyl vinyl ether) [PMVE], perfluoro(ethyl vinyl ether) [PEVE], and perfluoro(propyl vinyl ether) [PPVE] are preferred.

The above-mentioned PFA is not particularly limited, and preferably 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. A more preferred molar ratio is 70/30 or more and 98.9/1.1 or less, and a further preferred molar ratio is 80/20 or more and 98.9/1.1 or less. If the TFE unit is too little, the mechanical properties tend to be reduced; if it is too much, the melting point tends to be too high and the moldability tends to be reduced. The above-mentioned PFA is also preferably composed only of TFE units and PAVE units, and is also preferably a copolymer in which the monomer units 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, a vinyl monomer represented by CZ ¹ Z ² =CZ ³ (CF ₂ ) _n Z ⁴ (wherein Z ¹ , Z ² and Z ³ are the same or different and represent a hydrogen atom or a fluorine atom, Z ⁴ represents a hydrogen atom, a fluorine atom or a chlorine atom, and n represents an integer of 2 to 10), and an alkyl perfluorovinyl ether derivative represented by CF ₂ =CF-OCH ₂ -Rf ² (wherein Rf ² represents a perfluoroalkyl group having 1 to 5 carbon atoms).

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

In this specification, the thermal decomposition starting temperature is the temperature at which 10 mg of a sample is heated from room temperature at a heating rate of 10°C/min using a differential thermal-thermogravimetric analyzer [TG-DTA] (trade name: TG/DTA6200, manufactured by SEIKO Electronics Co., Ltd.) and the sample is reduced by 1% by mass.

The above-mentioned FEP is not particularly limited, and preferably a copolymer in which the molar ratio of TFE units to HFP units (TFE units/HFP units) is 70/30 or more and less than 99/1. A more preferred molar ratio is 70/30 or more and 98.9/1.1 or less, and a further preferred molar ratio is 80/20 or more and 98.9/1.1 or less. If the TFE unit is too little, the mechanical properties tend to decrease; if it is too much, the melting point is too high and the moldability tends to decrease. The above-mentioned FEP is preferably composed only of TFE units and HFP units, and is also preferably a copolymer in which the monomer units from monomers copolymerizable with TFE and HFP are 0.1 to 10 mol%, and the total of TFE units and HFP units is 90 to 99.9 mol%. Examples of the monomer copolymerizable with TFE and HFP include PAVE and an alkyl perfluorovinyl ether derivative represented by CF ₂ =CF-OCH ₂ -Rf ² (wherein Rf ² represents a perfluoroalkyl group having 1 to 5 carbon atoms).

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

The content of each monomer unit of the above-mentioned hot-melt fluororesin can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis according to the types of monomers.

The heat-fusible fluororesin is in the form of powder having an average particle size of 1.0 μm or less, so that it exhibits good dispersibility in the resulting coating film and can form a coating film having excellent heat resistance and non-stickiness on the surface.

The average particle size is preferably 0.5 μm or less. The average particle size is preferably 0.1 μm or more, and more preferably 0.3 μm or more. Within these ranges, film-forming properties and the meltability of the fluororesin during firing are excellent.

The average particle size is measured using "CAPA-700" manufactured by Horiba, Ltd. at a dispersion pressure of 1.0 bar without using a cascade, and the particle size corresponding to 50% of the cumulative particle size distribution is equal to the average particle size.

The above-mentioned hot-melt fluororesin can be obtained, for example, by referring to the method described in Japanese Patent Publication No. 1-25506. More specifically, the resin is obtained by emulsion polymerization in an aqueous medium with monomers coexisting, and the obtained dispersion is precipitated and dried without adding a surfactant.

Thereby, the average particle size can be made 1.0 μm or less.

In addition, by appropriately using a chain transfer agent, the MFR of the heat-fusible fluororesin can be controlled within the above range.

The chain transfer agent is preferably at least one selected from the group consisting of saturated hydrocarbons having 1 to 6 carbon atoms, alcohols having 1 to 4 carbon atoms, carboxylic acid ester compounds having 4 to 8 carbon atoms, chlorine-substituted hydrocarbons having 1 to 2 carbon atoms, ketones having 3 to 5 carbon atoms, and mercaptans having 10 to 12 carbon atoms.

From the viewpoints of dispersibility in the polymerization medium, chain transfer properties, and removability from the target product, the chain transfer agent is more preferably at least one selected from the group consisting of ethane, isopentane, methanol, isopropanol, acetone, and ethyl acetate.

The above-mentioned hot-melt fluororesin is preferably produced without using a fluorinated surfactant which is a perfluorocarboxylic acid having 8 to 14 carbon atoms and a salt thereof, and more preferably without using a fluorinated surfactant. Thus, a hot-melt fluororesin which does not contain a fluorinated surfactant, particularly does not contain the above-mentioned perfluorocarboxylic acid having 8 to 14 carbon atoms and a salt thereof, can be obtained.

Examples of the fluorinated surfactant include the following general formula (N ¹ ):

^Xn0- ( _CF2 ) _m1 - ^Y0 ( ^N1 )

(wherein ^Xn0 is H, Cl or F, m1 is an integer of 3 to 15, ^Y0 is _-SO3M , _-SO4M , _-SO3R , _-SO4R , -COOM, _{-PO3M2 , -PO4M2} (M is H, _NH4 or an alkali metal, and R is an alkyl group having 1 to ₁₂ carbon atoms)), a compound represented by the following general formula ( ^N2 ):

Rf ⁿ¹ -O-(CF(CF ₃ )CF ₂ O) _m2 CFX ⁿ¹ -Y ⁰ (N ² )

(wherein, Rf ⁿ¹ is a perfluoroalkyl group having 1 to 5 carbon atoms, m2 is an integer of 0 to 3, X ⁿ¹ is F or CF ₃ , and Y ⁰ is the group defined above).

In the coating composition disclosed in the present invention, the content of the above-mentioned hot-melt fluororesin is 10 to 200 parts by mass relative to 100 parts by mass of the above-mentioned heat-resistant binder resin. If the above-mentioned hot-melt fluororesin is too little, the sustainability of non-adhesion may be reduced; if it is too much, the adhesion between the obtained coating composition and the substrate may be reduced. From the perspective of further improving non-adhesion and adhesion, the content of the above-mentioned hot-melt fluororesin is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, and preferably 150 parts by mass or less, more preferably 120 parts by mass or less, relative to 100 parts by mass of the above-mentioned heat-resistant binder resin.

The coating composition of the present disclosure includes an organic solvent. The coating composition of the present disclosure may be a solvent-based coating composition.

The organic solvent is preferably an organic compound and is liquid at room temperature of about 20°C.

The organic solvent may be a solvent that dissolves the heat-resistant binder resin or a solvent that disperses the heat-fusible fluororesin.

Examples of the organic solvent include N-ethyl-2-pyrrolidone, 3-alkoxy-N,N-dimethylpropionamide, γ-butyrolactone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, N-formylmorpholine, N-acetylmorpholine, dimethylpropyleneurea, anisole, diethyl ether, ethylene glycol, acetophenone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, xylene, toluene, ethanol, 2-propanol, and the like. One or more of these may be used.

The organic solvent is preferably at least one selected from the group consisting of N-ethyl-2-pyrrolidone, 3-alkoxy-N,N-dimethylpropionamide, γ-butyrolactone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, N-formylmorpholine, N-acetylmorpholine, dimethylpropyleneurea, anisole, diethyl ether, ethylene glycol, acetophenone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, xylene, toluene, ethanol and 2-propanol, and more preferably selected from the group consisting of N-ethyl-2-pyrrolidone, 3 -alkoxy-N,N-dimethylpropionamide, γ-butyrolactone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, N-formylmorpholine, N-acetylmorpholine and dimethylpropyleneurea, and more preferably at least one selected from the group consisting of N-ethyl-2-pyrrolidone, 3-alkoxy-N,N-dimethylpropionamide, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, N-formylmorpholine, N-acetylmorpholine and dimethylpropyleneurea.

The above-mentioned 3-alkoxy-N,N-dimethylpropionamide is represented by N(CH ₃ ) ₂ COCH ₂ CH ₂ OR ¹¹ (R ¹¹ is an alkyl group). The alkoxy group (R ¹¹ O group) is not particularly limited, and is preferably an alkoxy group containing a lower alkyl group having about 1 to 6 carbon atoms, and more preferably a methoxy group, an ethoxy group, a propoxy group or a butoxy group. As the above-mentioned 3-alkoxy-N,N-dimethylpropionamide, 3-methoxy-N,N-dimethylpropionamide (N(CH ₃ ) ₂ COCH ₂ CH ₂ OCH ₃ ) is particularly preferred.

The amount of the organic solvent added can be selected within a range that allows the coating composition to have coating film-forming properties and a coating viscosity suitable for a coating method.

In the coating composition of the present disclosure, the total amount of N-methyl-2-pyrrolidone, N,N-dimethylacetamide and N,N-dimethylformamide is preferably less than 0.1% by mass relative to the coating composition. The total amount is more preferably less than 0.01% by mass, and further preferably less than 0.001% by mass.

The above total amount is a value measured by liquid chromatography.

The coating composition of the present disclosure also preferably does not include any of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide.

In the coating composition of the present disclosure, the water content is preferably less than 1% by mass based on the coating composition.

The water content can be measured by the Karl Fischer method.

In the coating composition of the present disclosure, the content of the perfluorocarboxylic acid and its salt having 8 or more and 14 or less carbon atoms is preferably less than 25 ppb by mass relative to the coating composition. The content is more preferably 20 ppb by mass or less, further preferably 15 ppb by mass or less, further more preferably 10 ppb by mass or less, particularly preferably 5 ppb by mass or less, and most preferably less than 5 ppb by mass.

The content of the perfluorocarboxylic acid and the salt thereof can be measured by liquid chromatography.

In the coating composition of the present disclosure, the content of the fluorinated surfactant is preferably less than 25 ppb by mass relative to the coating composition. The above content is more preferably 20 ppb by mass or less, further preferably 15 ppb by mass or less, further more preferably 10 ppb by mass or less, particularly preferably 5 ppb by mass or less, and most preferably less than 5 ppb by mass.

The content of the fluorinated surfactant can be measured by liquid chromatography.

The coating composition of the present disclosure may further contain conventionally used additives such as pigments, brighteners, antimicrobial agents, and fillers as other components within the range that does not impair the effects of the coating composition of the present disclosure.

The total amount of the other components except the surfactant may be not more than 50% by mass of the total amount of the heat-resistant binder and the hot-melt fluororesin in order not to reduce the non-adhesiveness of the coating film formed of the obtained coating composition.

The coating composition of the present disclosure can be produced by a conventional method, for example, by stirring and mixing the components using a stirring and mixing device such as a ball mill, a triple roll mill, or a disperser.

In the coating composition of the present disclosure, the solid content concentration is preferably 10 to 50% by mass, more preferably 15% by mass or more, and more preferably 35% by mass or less, from the viewpoint of coatability.

The present disclosure also relates to a coated product including a substrate and a coating film, wherein the coating film is provided on the substrate and is formed from the coating composition of the present disclosure.

The coated product of the present disclosure is excellent in the sustainability of non-stickiness.

Furthermore, the coated product of the present disclosure is also excellent in surface smoothness.

Examples of the material of the substrate include metals such as iron, aluminum, copper, and alloys thereof, metals such as plated steel sheets, and non-metallic inorganic materials such as enamel, glass, and ceramics. Examples of the alloys include stainless steel.

Furthermore, a primer such as a rust-proof primer may be provided on the substrate as required.

Examples of the shape of the substrate include a plate shape, a rod shape, and a spherical shape, and the substrate may be in the final shape of a desired coated article.

When the coating composition is applied to the above-mentioned substrate, it can be applied by conventional methods, for example, using a roll coater, a flow coater, a sprayer, etc. In addition, from the aspect of adhesion to the substrate, it is preferably applied after the surface of the substrate is treated by sandblasting, acid, alkali, chromate, etc.

Firing may be performed after coating.

When the coating composition of the present disclosure is applied to a substrate, the dry film thickness may be in a range that does not impair heat resistance, and is preferably 5 to 40 μm from the viewpoint of sustainability of non-stickiness, and more preferably 10 to 20 μm from the viewpoint of processability.

The use to which the coating composition of the present disclosure and the coated article of the present disclosure can be applied is not particularly limited, and examples thereof include uses utilizing the properties of hot-melt fluororesins such as corrosion resistance, heat resistance, non-stickiness, and sliding properties. For example, the invention can include: cooking devices such as frying pans, pressure cookers, pots, baking trays, rice cookers, ovens, hot plates, bread baking molds, kitchen knives, gas stoves (such as top plates), microwave ovens (such as inner wall materials); kitchen appliances such as electric kettles, oil pots, ice trays, molds, and range hoods; food industry parts such as stirring rollers, calender rollers, conveyors, and hoppers; industrial products such as rollers for office automation (OA), belts for OA, separation claws for OA, papermaking rollers, and calender rollers for film manufacturing; injection molds, molds for foamed styrene molding, and casting molds; mold release for molding molds such as stripper plates for plywood and decorative board manufacturing; industrial containers (especially for the semiconductor industry); tools such as saws and files; household items such as irons, scissors, and kitchen knives; metal foil; electric wires; sliding bearings for food processing machines, packaging machines, textile machinery, etc.; sliding parts for cameras and clocks; automobile parts such as pipes, valves, and bearings; snow shovels; hoes; chutes, etc.

The coating composition and the coated product of the present disclosure are preferably used in a cooking device or kitchenware. The coated product of the present disclosure is also preferably a cooking device, kitchenware, or a component thereof.

As the above-mentioned cooking device or kitchenware, a frying pan, a top plate of a gas stove, and an inner wall material of a microwave oven are preferred.

Example

Next, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

Each numerical value in the examples was measured by the following method.

(Melting Point)

Thermal measurement was performed using a differential scanning calorimeter at a heating rate of 10° C./min in accordance with ASTM D-4591, and the peak temperature of the obtained endothermic curve was determined as the melting point.

(MFR)

The mass (g/10 minutes) of the polymer flowing out from a nozzle having an inner diameter of 2 mm and a length of 8 mm at 372° C. and a load of 5 kg per 10 minutes was measured using a melt flow indexer (manufactured by Yasuda Seiki Co., Ltd.) in accordance with ASTM D 1238 to obtain MFR.

(Average particle size)

The measurement was performed using "CAPA-700" manufactured by Horiba, Ltd. at a dispersion pressure of 1.0 bar without using a cascade, and the particle size corresponding to 50% of the cumulative particle size distribution was defined as the average particle size.

Example 1

10 g of polyethersulfone resin (PES5003P, manufactured by Sumitomo Chemical Co., Ltd.) and 10 g of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA1, melting point 318°C, MFR 30 g/10 min, average particle size 0.3 μm) were added to a mixed solvent of 50 g of N-ethyl-2-pyrrolidone, 15 g of methyl isobutyl ketone, and 15 g of xylene, and dissolved and dispersed using a ball mill to obtain the coating composition of the present disclosure. Next, the composition was applied to a 0.5 mm stainless steel plate subjected to a coating type chromate treatment using a bar coater so that the dry film thickness was 10 μm, and fired at 400°C for 90 seconds to obtain the coated product of the present disclosure.

Example 2

10 g of a polyethersulfone resin (PES5003P, manufactured by Sumitomo Chemical Industries, Ltd.), 10 g of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA1, melting point 318°C, MFR 30 g/10 min, average particle size 0.3 μm), and 5 g of a composite oxide pigment (DAIPYROXIDE color number #9510, manufactured by Dainippon Seika Industries, Ltd.) were added to a mixed solvent of 47 g of N-ethyl-2-pyrrolidone, 14 g of methyl isobutyl ketone, and 13 g of xylene, and dissolved and dispersed using a ball mill. 1 g of aluminum flakes (HS-2, manufactured by Toyo Aluminum Co., Ltd.) were further added and stirred and dispersed. A coating composition and a coated product were obtained in the same manner as in Example 1, except that the above procedures were repeated.

Example 3

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether-hexafluoropropylene copolymer (FEP1, melting point 282° C., MFR 30 g/10 min, average particle size 0.2 μm) was used instead of PFA1.

Example 4

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA2, melting point 304°C, MFR 31 g/10 min, average particle size 0.15 μm) was used instead of PFA1.

Example 5

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA3, melting point 316°C, MFR 16 g/10 min, average particle size 0.3 μm) was used instead of PFA1.

Example 6

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA4, melting point 316°C, MFR 43 g/10 min, average particle size 0.3 μm) was used instead of PFA1.

Example 7

A coating composition and a coated product were obtained in the same manner as in Example 1 except that 14 g of a polyethersulfone resin (PES5003P, manufactured by Sumitomo Chemical Co., Ltd.) and 7 g of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA1, melting point 318° C., MFR 30 g/10 min, average particle size 0.3 μm) were used.

Example 8

A coating composition and a coated product were obtained in the same manner as in Example 1 except that 8 g of a polyethersulfone resin (PES5003P, manufactured by Sumitomo Chemical Co., Ltd.) and 12 g of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA1, melting point 318°C, MFR 30 g/10 min, average particle size 0.3 μm) were used.

Example 9

A coating composition and a coated product were obtained in the same manner as in Example 1 except that 3-methoxy-N,N-dimethylpropionamide was used instead of the N-ethyl-2-pyrrolidone.

Example 10

A coating composition and a coated product were obtained in the same manner as in Example 1 except that 1,3-dimethyl-2-imidazolidinone was used instead of the N-ethyl-2-pyrrolidone.

Embodiment 11

A coating composition and a coated product were obtained in the same manner as in Example 1, except that 33 g of a polyamide-imide resin (HPC-3010, manufactured by Showa Denko Materials Co., Ltd., a γ-butyrolactone-soluble product, solid content concentration 30%) was added to a mixed solvent of 27 g of N-ethyl-2-pyrrolidone, 15 g of methyl isobutyl ketone, and 15 g of xylene.

Example 12

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a polyetherimide resin (Ultem 1000, manufactured by SABIC) was used instead of the polyethersulfone resin.

Comparative Example 1

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA5, melting point 316°C, MFR 11 g/10 min, average particle size 0.3 μm) was used instead of PFA1.

Comparative Example 2

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA6, melting point 317° C., MFR 62 g/10 min, average particle size 0.3 μm) was used instead of PFA1.

Comparative Example 3

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether-hexafluoropropylene copolymer (FEP2, melting point 241° C., MFR 29 g/10 min, average particle size 0.2 μm) was used instead of PFA1.

Comparative Example 4

A coating composition and a coated product were obtained in the same manner as in Example 1 except that a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA7, melting point 304°C, MFR 31 g/10 min, average particle size 5 μm) was used instead of PFA1.

Comparative Example 5

A coating composition and a coated product were obtained in the same manner as in Example 1 except that 10 g of a polyethersulfone resin (PES5003P, manufactured by Sumitomo Chemical Co., Ltd.) and 0.9 g of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA1, melting point 318°C, MFR 30 g/10 min, average particle size 0.3 μm) were used.

Comparative Example 6

A coating composition and a coated product were obtained in the same manner as in Example 1 except that 6 g of a polyethersulfone resin (PES5003P, manufactured by Sumitomo Chemical Co., Ltd.) and 15 g of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA1, melting point 318°C, MFR 30 g/10 min, average particle size 0.3 μm) were used.

The coated products obtained in Examples and Comparative Examples were cut to obtain test pieces, and the test pieces were tested and evaluated according to the following items.

[Test method]

(1) Surface roughness (surface smoothness)

The surface roughness (Ra) of the test piece was measured using Surtronic DuoII (manufactured by Taylor Hobson).

(2) Initial non-adhesiveness

A contamination liquid consisting of egg/sugar/soy sauce = 1/1/1 (mass ratio) was dropped on the test piece, baked at 260°C for 30 minutes, and then the contamination was removed with a fingernail. The case where the contamination could be easily removed and there was almost no attachment on the coating film was recorded as A, the case where the contamination could be easily removed but there was attachment to the extent that it could be scraped off with a fingernail was recorded as B, the case where the contamination was difficult to remove and there was attachment to the extent that it could be scraped off with a fingernail was recorded as C, the case where the contamination was difficult to remove and there was attachment that could not be removed even by scratching with a fingernail was recorded as D, and the case where the contamination was not removed and the coating film was peeled off was recorded as E.

(3) Non-adhesive durability

The above-mentioned initial non-stick test was regarded as one cycle, and the number of cycles until the contaminants could no longer be removed was examined.

[Table 1]

Claims (2)

1. A coating composition comprising a heat-resistant binder resin, a hot-melt fluororesin and an organic solvent, wherein: The heat-fusible fluororesin is a powder having an average particle size of 1.0 μm or less, a melting point of 270° C. or more, and a melt flow rate of 15 g/10 min to 45 g/10 min, The amount of the heat-meltable fluororesin is 10 to 200 parts by mass based on 100 parts by mass of the heat-resistant binder resin. 2. A coated article comprising a substrate and a coating film, wherein the coating film is provided on the substrate and is formed from the coating composition according to claim 1.