JP5445587B2 - Coated article manufacturing method and coated article - Google Patents

Description

The present invention relates to a method for producing a coated article and a coated article.

Fluorine-containing polymers such as tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer [PFA] have a low coefficient of friction and are excellent in properties such as non-adhesiveness, chemical resistance, and heat resistance. It is widely used for surface processing of food industry supplies, kitchen utensils such as frying pans and pans, household items such as irons, electrical industry supplies, and machine industry supplies.

Surface processing is performed by forming a layer made of a fluorine-containing polymer on a substrate. If the fluorine-containing polymer to be used is melt-processable such as PFA, a thick layer is produced by a general industrial production method. The surface of the resulting article can easily exhibit various properties of the fluorine-containing polymer.

However, the fluorine-containing polymer has poor adhesion to the substrate due to its non-adhesiveness. For the purpose of improving the adhesion, a primer layer obtained by preliminarily applying a primer containing a binder resin such as a heat-resistant resin and a fluorine-containing polymer as an undercoat, and a primer layer obtained and a layer comprising a fluorine-containing polymer A laminate having

In such a laminate, a filler may be added at the time of formation for the purpose of imparting design properties, improving strength, and the like.For example, when a glitter feeling is required as a design property, a glitter filler is added. Yes.

As a laminate having a glitter feeling, there is a laminate having a two-layer structure of a primer layer to which mica is added as a glitter filler and a topcoat layer made of PFA formed thereon. However, this laminate has a problem that mica powder and glass powder easily settle in the primer layer, and the glitter feeling is not sufficient.

In order to solve this problem, it has been proposed to use aluminum powder instead of mica powder as a glittering filler, but aluminum powder is more likely to settle than mica, and the glitter of the resulting laminate when mass-produced. However, there is a problem that the corrosion resistance is adversely affected.

As a laminate having a stable glitter and excellent corrosion resistance, a layer composed of polytetrafluoroethylene [PTFE] and mica is used as an intermediate layer, and a primer layer composed of a binder resin and a fluorine-containing polymer thereunder And a laminate having a three-layer structure in which a topcoat layer is formed using a powder paint made of PFA has been proposed (see, for example, Patent Documents 1 and 2). This laminate is stable in glitter even when mass-produced. However, when the article comprising the laminate and the substrate is used for a kitchen appliance such as a pan, the steam resistance is not sufficient, and there is a possibility that blisters are generated by the steam.

Among the laminates to which a filler is added at the time of formation, a primer layer using aluminum oxide as a filler is formed on a base material as having excellent scratch resistance, and PFA or the like is formed on the primer layer. An intermediate layer made of a melt-processable fluorine-containing polymer, PTFE, and aluminum oxide is formed, and a topcoat layer made of PTFE is formed on the intermediate layer (see, for example, Patent Document 3). However, this laminate has an adverse effect on the corrosion resistance of the base material because aluminum oxide may settle in the primer layer, and the top coat layer is made of PTFE. It was not easy to obtain a thick layer, and there was a problem that durability such as wear resistance was inferior.

As a laminate to which a filler is added at the time of formation, a primer layer (A) composed of a fluoropolymer (a) and a heat-resistant resin, a melt-processable fluoropolymer (b) and a filler are also included. A fluorine-containing laminate having a fluorine layer (B) and a fluorine-containing layer (C) comprising a melt-processable fluorine-containing polymer (c) is disclosed (for example, see Patent Document 4).

Japanese Patent Laid-Open No. 7-11946 Japanese Patent No. 25933043 Japanese Patent No. 2644380 International Publication No. 2004/041537 Pamphlet

However, in the fluorine-containing laminate disclosed in Patent Document 4, a fluorine-containing layer (B) comprising a melt-processable fluorine-containing polymer (b) and a filler is formed by applying a liquid paint. In this case, depending on the intended use, the corrosion resistance and water vapor resistance may not be sufficient, and there is room for improvement. Moreover, when the fluorine-containing layer (B) is a liquid paint, a drying process and a cooling process are required before the fluorine-containing layer (C) is applied, and the manufacturing method is complicated.

In view of the above situation, the object of the present invention is excellent in corrosion resistance, water vapor resistance and wear resistance, has a simple manufacturing process, and can stably exhibit the characteristics of a filler such as glitter even during mass production. It is in providing the manufacturing method of a coated article, and a coated article.

The present invention comprises a step (1) of forming a primer coating layer (Ap) on a substrate by applying a primer coating composition (i) comprising a fluoropolymer (a) and a heat resistant resin, On the primer coating layer (Ap), a fluorine-containing powder coating layer (Bp) is formed by coating a fluorine-containing powder (ii) comprising a melt-processable fluorine-containing polymer (b) and a filler. Step (2): Applying a fluorine-containing powder (iii) comprising a melt-processable fluorine-containing polymer (c) on the fluorine-containing powder layer (Bp) to form a fluorine-containing powder coating layer (Cp) By firing the laminate comprising the step (3) of forming, and the base material, the primer coating layer (Ap), the fluorine-containing powder coating layer (Bp), and the fluorine-containing powder coating layer (Cp). , Substrate, primer layer (A), fluorine-containing layer ( ) And a method for producing a coated article which comprises a step (4) to form a coated article comprising a fluorinated layer (C).

The present invention is also a coated article obtained by the above production method. The coated article obtained by the production method of the present invention has more excellent corrosion resistance and water vapor resistance because the fluorine-containing layer (B) is produced from the fluorine-containing powder (ii). For example, when the fluorine-containing layer laminated | stacked on the primer layer is formed with the liquid coating material, it may be inferior to corrosion resistance or water vapor resistance.
The present invention is described in detail below.

In the method for producing a coated article of the present invention, a primer coating layer (Ap) is formed on a substrate by applying a primer coating composition (i) comprising a fluoropolymer (a) and a heat resistant resin. Step (1) to include.

The substrate is not particularly limited, and examples thereof include simple metals such as iron, aluminum and copper and metals such as alloys thereof; nonmetallic inorganic materials such as enamel, glass and ceramics. Examples of the alloys include stainless steel. As said base material, a metal is preferable and aluminum or stainless steel is more preferable.

The base material may be subjected to a surface treatment such as a degreasing treatment or a surface roughening treatment, if necessary. The surface roughening treatment method is not particularly limited, and examples thereof include chemical etching with acid or alkali, anodization (alumite treatment), and sandblasting. From the point that the said surface treatment can apply | coat the said coating composition for primers (i) uniformly, without producing repellency, and the adhesiveness of a base material and a primer application layer (Ap), etc., What is necessary is just to select suitably according to types, such as a base material and the coating composition (i) for primers, For example, it is preferable that it is a sandblast.

The fluoropolymer (a) is a polymer having a fluorine atom that is directly bonded to the carbon atom constituting the main chain or side chain. The fluoropolymer (a) may be non-melt processable or melt processable.

The fluorinated polymer (a) is preferably obtained by polymerizing a fluorinated monoethylenically unsaturated hydrocarbon (I).

The above-mentioned “fluorinated monoethylenically unsaturated hydrocarbon (I)” (hereinafter referred to as “unsaturated hydrocarbon (I)”) is a vinyl group in which part or all of the hydrogen atoms are substituted by fluorine atoms. Is an unsaturated hydrocarbon having one in the molecule.

In the unsaturated hydrocarbon (I), a part or all of hydrogen atoms not substituted by fluorine atoms are halogen atoms other than fluorine atoms such as chlorine atoms and / or fluoroalkyl groups such as trifluoromethyl groups. It may be substituted by. However, the unsaturated hydrocarbon (I) excludes trifluoroethylene described later.

The unsaturated hydrocarbon (I) is not particularly limited, and examples thereof include tetrafluoroethylene [TFE], hexafluoropropylene [HFP], chlorotrifluoroethylene [CTFE], vinylidene fluoride [VdF], and vinyl fluoride [ VF] and the like, and one or more of these can be used.

The fluoropolymer (a) may be a homopolymer of the unsaturated hydrocarbon (I). Examples of the homopolymer of the unsaturated hydrocarbon (I) include, for example, tetrafluoroethylene homopolymer [TFE homopolymer], polychlorotrifluoroethylene [PCTFE], polyvinylidene fluoride [PVdF], polyvinyl fluoride [PVF]. ] Etc. are mentioned.

The fluoropolymer (a) is also a copolymer of at least one kind of the unsaturated hydrocarbon (I) and an unsaturated compound (II) that can be copolymerized with the unsaturated hydrocarbon (I). It may be.

The unsaturated compound (II) does not use a polymer obtained by polymerizing only one or more unsaturated compounds (II) as the fluoropolymer (a). A polymer obtained by polymerizing only one or two or more of the unsaturated hydrocarbons (I) as the unsaturated hydrocarbon (I) can be used as the fluoropolymer (a). Is different from the unsaturated hydrocarbon (I).

The unsaturated compound (II) is not particularly limited, and examples thereof include trifluoroethylene [3FH]; monoethylenically unsaturated hydrocarbons such as ethylene [Et] and propylene [Pr]. These can use 1 type (s) or 2 or more types.

The fluoropolymer (a) may be a copolymer of two or more unsaturated hydrocarbons (I). The copolymer of the two or more unsaturated hydrocarbons (I) and the copolymer of the at least one unsaturated hydrocarbon (I) and the unsaturated compound (II) are not particularly limited. Examples thereof include binary copolymers and ternary copolymers.

The binary copolymer is not particularly limited, and examples thereof include a VdF / HFP copolymer, an Et / CTFE copolymer [ECTFE], an Et / HFP copolymer, and the like.
The binary copolymer is also a TFE / HFP copolymer [FEP], a TFE / CTFE copolymer, a TFE / VdF copolymer, a TFE / 3FH copolymer, an Et / TFE copolymer [ETFE]. TFE copolymers such as TFE / Pr copolymer may be used. In the present specification, the “TFE copolymer” means a copolymer obtained by copolymerizing TFE and one or more monomers other than TFE. In the TFE copolymer, the proportion of other monomers other than TFE added to the TFE copolymer is usually 1 mass of the total mass of the TFE and the other monomers. % Is preferably exceeded.

Examples of the ternary copolymer include VdF / TFE / HFP copolymer.

The other monomer other than the TFE in the TFE copolymer may be another monomer (III) that can be copolymerized with the following TFE. The other monomer (III) is represented by the following general formula _{X (CF 2) m O n} CF = CF 2
(Wherein X represents —H, —Cl or —F, m represents an integer of 1 to 6, and n represents an integer of 0 or 1) (however, HFP excluding.), the following general formula _{C 3 F 7 O [CF (} CF 3) CF 2 O] p -CF = CF 2
(Wherein p represents an integer of 1 or 2), or the following general formula X (CF ₂ ) _q CY═CH ₂
(Wherein X is the same as above, Y represents —H or —F, and q represents an integer of 1 to 6). At least one selected from the group consisting of compounds represented by A seed monomer is preferred. These can use 1 type (s) or 2 or more types. Examples of such a TFE copolymer include TFE / perfluoro (alkyl vinyl ether) [PAVE] copolymer [PFA].

The fluoropolymer (a) may also be modified polytetrafluoroethylene [modified PTFE]. In the present specification, the “modified PTFE” means a product obtained by copolymerizing a small amount of a comonomer with TFE so as not to impart melt processability to the obtained copolymer. The small amount of the comonomer is not particularly limited, and examples thereof include HFP and CTFE among the unsaturated hydrocarbons (I), and 3FH among the unsaturated compounds (II). Among other monomers (III), PAVE, perfluoro (alkoxy vinyl ether), (perfluoroalkyl) ethylene and the like can be mentioned. One kind or two or more kinds of the small amount of comonomer can be used.

The ratio in which the small amount of the comonomer is added to the modified PTFE varies depending on the type thereof. For example, when PAVE, perfluoro (alkoxy vinyl ether) or the like is used, the TFE and the small amount of the comonomer are usually used. It is preferable that it is 0.001-1 mass% of the total mass with a weight body.

The fluorine-containing polymer (a) may be a single polymer or a mixture of two or more polymers. One of the homopolymers of the unsaturated hydrocarbon (I) and the unsaturated hydrocarbon (I ), Or a mixture of two or more of the unsaturated hydrocarbon (I) copolymers.

Examples of the mixture include a mixture of a TFE homopolymer and the TFE copolymer, a mixture of two or more types of copolymers belonging to the TFE copolymer, and the like. Examples thereof include a mixture of TFE homopolymer and PFA, a mixture of TFE homopolymer and FEP, a mixture of TFE homopolymer, PFA and FEP, a mixture of PFA and FEP, and the like.

The fluoropolymer (a) also contains a perfluoroalkyl group-containing ethylenically unsaturated monomer (IV) having a perfluoroalkyl group (hereinafter referred to as “unsaturated monomer (IV)”). It may be obtained by polymerization. The unsaturated monomer (IV) has the following general formula

(In the formula, Rf represents a perfluoroalkyl group having 4 to 20 carbon atoms, R ¹ represents —H or an alkyl group having 1 to 10 carbon atoms, and R ² represents an alkylene group having 1 to 10 carbon atoms. R ³ represents —H or a methyl group, R ⁴ represents an alkyl group having 1 to 17 carbon atoms, r represents an integer of 1 to 10, and s represents an integer of 0 to 10. It is expressed by.)
The fluoropolymer (a) may be a homopolymer of the unsaturated monomer (IV), or the unsaturated monomer (IV) and the unsaturated monomer (IV). ) And a copolymer with the monomer (V) that can be copolymerized.

The monomer (V) is not particularly limited, and examples thereof include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, polyethylene glycol di (meth) acrylate, N-methylolpropane acrylamide, and (meth) acryl. (Meth) acrylic acid derivatives such as acid amides and alkyl esters of (meth) acrylic acid having an alkyl group having 1 to 20 carbon atoms; ethylene, vinyl chloride, vinyl fluoride, styrene, α-methylstyrene, p-methyl Substituted or unsubstituted ethylene such as styrene; alkyl vinyl ethers having 1 to 20 carbon atoms in the alkyl group; vinyl ethers such as halogenated alkyl vinyl ethers having 1 to 20 carbon atoms in the alkyl group; Vinyl ketones such as vinyl alkyl ketones of ˜20; Aliphatic unsaturated polycarboxylic acids and derivatives thereof such as phosphate; butadiene, isoprene, polyenes such as chloroprene.

The fluoropolymer (a) can be obtained, for example, by using a conventionally known polymerization method such as emulsion polymerization.

As said fluoropolymer (a), at least 1 sort (s) selected from the group which consists of a TFE homopolymer, a modified PTFE, and the said TFE type copolymer from the point which the coated article obtained is excellent in corrosion resistance and water vapor resistance. A polymer is preferred. The TFE copolymer is preferably at least one copolymer selected from the group consisting of FEP and PFA.

From the above, the fluoropolymer (a) is preferably at least one polymer selected from the group consisting of TFE homopolymer, modified PTFE, FEP and PFA.

As the above-mentioned fluoropolymer (a), in the obtained coated article, there are those containing a TFE copolymer from the viewpoint of excellent adhesion between the primer layer (A) and the fluorine-containing layer (B). preferable. Since the coated article having excellent adhesion between the primer layer (A) and the fluorine-containing layer (B) has excellent water vapor resistance, it can suppress the occurrence of coating film defects such as blisters even in the presence of water vapor. it can. Examples of the fluorine-containing polymer (a) containing a TFE copolymer include PFA alone, a mixture of TFE homopolymer and FEP, a mixture of TFE homopolymer and PFA, a mixture of modified PTFE and FEP, or A mixture of modified PTFE and PFA is preferred. Moreover, the fluorine-containing polymer (a) in the primer layer (A) is because the obtained coated article is excellent in corrosion resistance and water vapor resistance, and the adhesion between the primer layer (A) and the fluorine-containing layer (B) is excellent. , PFA alone, a mixture of TFE homopolymer and PFA, or a mixture of TFE homopolymer and FEP is preferable, and a mixture of TFE homopolymer and FEP is more preferable.

The heat-resistant resin may be any resin that is generally recognized as having heat resistance, and is preferably a resin having a continuous usable temperature of 150 ° C. or higher. However, the above-mentioned fluoropolymer (a) is excluded as the heat-resistant resin.

The heat-resistant resin is not particularly limited. For example, from the group consisting of polyamideimide resin, polyimide resin, polyethersulfone resin, polyetherimide resin, polyetheretherketone resin, aromatic polyester resin and polyarylene sulfide resin. It is preferable that it is at least one selected resin. As said heat resistant resin, the said resin can use 1 type (s) or 2 or more types.

The polyamide-imide resin [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. For example, a reaction between an aromatic diamine having an amide bond in the molecule and an aromatic tetravalent carboxylic acid such as pyromellitic acid; an aromatic trivalent carboxylic acid such as trimellitic anhydride; It consists of a high molecular weight polymer obtained by a reaction with a diamine such as 4,4-diaminophenyl ether or a diisocyanate such as diphenylmethane diisocyanate; a reaction between a dibasic acid having an aromatic imide ring in the molecule and a diamine. Examples thereof include resins. As said PAI, what consists of a polymer which has an aromatic ring in a principal chain from the point which is excellent in heat resistance is preferable.

The polyimide resin [PI] is a resin made of a polymer having an imide bond in the molecular structure. The PI is not particularly limited, and examples thereof include a resin made of a high molecular weight polymer obtained by a reaction of an aromatic tetravalent carboxylic anhydride such as pyromellitic anhydride. As said PI, what consists of a polymer which has an aromatic ring in a principal chain from the point which is excellent in heat resistance is preferable.

The polyethersulfone resin [PES] has the following chemical formula:

It is resin which consists of a polymer which has a repeating unit represented by these. The PES is not particularly limited, and examples thereof include a resin made of a polymer obtained by polycondensation of dichlorodiphenyl sulfone and bisphenol.

The above heat-resistant resin has excellent adhesion to the substrate, has sufficient heat resistance even at the firing temperature when forming a coated article, and the resulting coated article has excellent corrosion resistance and water vapor resistance Therefore, at least one resin selected from the group consisting of PAI, PI and PES is preferable. Each of PAI, PI, and PES may be composed of one type or two or more types.

The heat resistant resin is more preferably at least one resin selected from the group consisting of PAI and PI from the viewpoint of excellent adhesion to the substrate and heat resistance.

The heat resistant resin is preferably composed of PES and at least one resin selected from the group consisting of PAI and PI from the viewpoint of excellent corrosion resistance and water vapor resistance. That is, the heat resistant resin may be a mixture of PES and PAI, a mixture of PES and PI, or a mixture of PES, PAI, and PI. The heat-resistant resin is particularly preferably a mixture of PES and PAI.

In the step (1), the primer coating composition (i) is composed of a fluoropolymer (a) and a heat resistant resin. The primer coating composition (i) may be liquid or powder. When the primer coating composition (i) is in a liquid state, it is composed of a liquid medium together with the fluoropolymer (a) and a heat-resistant resin. The liquid medium is usually composed of water and / or an organic liquid. In the present specification, the “organic liquid” means an organic compound that is liquid at a room temperature of about 20 ° C.

When the liquid medium of the primer coating composition (i) is mainly composed of an organic liquid, the heat-resistant resin and the fluoropolymer (a) are dispersed in the liquid medium as particles, and / or Or it melt | dissolves in the said liquid medium. The organic liquid is not particularly limited, and examples thereof include nitrogen-containing organic liquids such as N-methyl-2-pyrrolidone, 2-pyrrolidone and N, N-dimethylacetamide; toluene, xylene, trimethylbenzene, methylethylbenzene, propylbenzene, Aromatic hydrocarbon solvents such as butylbenzene; saturated hydrocarbon solvents having 6 to 12 carbon atoms; lactones such as γ-butyrolactone; acyclic esters such as butyl acetate; ketones such as methyl isobutyl ketone and methyl ethyl ketone Glycols such as ethylene glycol, triethylene glycol and propylene glycol; glycol ethers such as butyl cellosolve; monoalcohols such as 1-butanol and diacetone alcohol;

As the aromatic hydrocarbon solvent, commercially available products such as Solvesso 100, Solvesso 150, Solvesso 200 (all trade names, manufactured by Exxon Chemical) may be used. As the saturated hydrocarbon solvent, a commercially available mineral spirit (Japanese Industrial Standard, Industrial Gasoline No. 4) or the like may be used.

The said organic liquid may be used independently and may use 2 or more types together.

When the liquid medium of the primer coating composition (i) is mainly composed of water, the heat-resistant resin is dispersed as particles in the liquid medium or dissolved in the liquid medium. The fluoropolymer (a) is dispersed as particles in the liquid medium.

The primer coating composition (i) is usually a surfactant for the purpose of dispersing and stabilizing the particles comprising the fluoropolymer (a) when the liquid medium is mainly composed of water. Is added. The surfactant is not particularly limited. For example, nonionic surfactants such as fluorine-containing nonionic surfactants; anionic surfactants such as fluorine-containing anionic surfactants; fluorine-containing cationic interfaces Examples include cationic surfactants such as activators. The primer coating composition (i) can be used in combination with the organic liquid together with the surfactant for the purpose of dispersing and stabilizing the particles comprising the fluoropolymer (a).

The primer coating composition (i) is also prepared by the method described in JP-B-49-17017, that is, particles whose dispersoid is composed of the fluoropolymer (a) and heat-resistant resin. From an aqueous dispersion in which the dispersion medium is mainly composed of water, an organic solvent and a layer transfer agent as a layer transfer liquid are added, and the particles including the fluoropolymer (a) and the heat resistant resin are added. It may be an organosol obtained by, for example, a method of transferring the particles to the organic solvent.

The primer coating composition (i) is preferably a liquid from the viewpoint of excellent adhesion to the substrate, and more preferably a liquid medium mainly composed of water from the viewpoint of reducing environmental burden. .

When the primer coating composition (i) is in a liquid state, the viscosity of the primer coating composition (i) is preferably 0.1 to 50000 mPa · s. When it is less than 0.1 mPa · s, sagging or the like is likely to occur at the time of application on the substrate, and it may be difficult to obtain a target film thickness. In some cases, the thickness of the resulting primer coating layer (Ap) may not be uniform, resulting in poor surface smoothness or the like. A more preferred lower limit is 1 mPa · s, and a more preferred upper limit is 30000 mPa · s.

In the primer coating composition (i), the fluoropolymer (a) preferably has an average particle diameter of 0.01 to 5 μm. When the said heat resistant resin is disperse | distributing as particle | grains in the said coating composition for primers (i), that whose average particle diameter is 0.2-8 micrometers is preferable.

In the primer coating composition (i), the heat-resistant resin is composed of a polyethersulfone resin and at least one resin selected from the group consisting of a polyamideimide resin and a polyimide resin. It is preferable that it is 65-90 mass% of the total amount of this polyethersulfone resin and the at least 1 sort (s) of resin selected from the group which consists of the said polyamideimide resin and a polyimide resin. If it is less than 65% by mass, the steam resistance of the resulting coated article may be lowered, and if it exceeds 90% by mass, the corrosion resistance may be lowered. A more preferred upper limit is 85% by mass. The ratio of the PES is substantially the same in the primer layer (A) because the above-mentioned heat-resistant resin is not decomposed even in firing usually performed when forming a coated article. In addition, "the total amount of PES and PAI and PI" is either PAI or PI contained in the primer coating composition (i) when only one of PAI and PI is included. One is the total amount of PES.

In the primer coating composition (i), the heat-resistant resin is preferably 15 to 50 mass% of the total amount of the heat-resistant resin and the fluoropolymer (a). When the heat resistant resin is less than 15% by mass of the total amount of the heat resistant resin and the fluoropolymer (a), the adhesion between the primer layer (A) and the substrate in the resulting coated article is not sufficient. There may not be. If it exceeds 50% by mass, the adhesion between the primer layer (A) and the fluorine-containing layer (B) in the resulting coated article may not be sufficient. A more preferable lower limit is 20% by mass, and a more preferable upper limit is 40% by mass.

The total amount of the heat-resistant resin and the fluorinated polymer (a) may be the total amount of the solid content of the heat-resistant resin and the fluorinated polymer (a). The term “solid” means a solid at 20 ° C. In the present specification, the “total amount of solid content of the heat-resistant resin and the fluoropolymer (a)” means a temperature of 80 to 100 ° C. after the coating composition (i) for primer is applied on a substrate. Means the total mass of the heat-resistant resin and the fluoropolymer (a) in the residue after drying at 380 to 400 ° C. for 45 minutes.

The primer coating composition (i), together with the fluoropolymer (a) and the heat-resistant resin, further improves the coating workability and the corrosion resistance and water vapor resistance of the resulting coated article. You may consist of additives other than the filler in the fluorine-containing layer (B) mentioned later.

The additive is not particularly limited, and for example, a leveling agent, a solid lubricant, an anti-settling agent, a moisture absorbent, a surface conditioner, a thixotropic agent, a viscosity modifier, an antigelling agent, an ultraviolet absorber, a light Stabilizer, plasticizer, anti-coloring agent, anti-skinning agent, anti-scratch agent, anti-mold agent, antibacterial agent, antioxidant, anti-static agent, silane coupling agent, wood powder, quartz sand, carbon black, Brilliant flat pigments such as clay, talc, diamond, tourmaline, cocoon, germanium, extender pigments, aluminum flakes, scaly pigments, glass, various reinforcing materials, various fillers, conductive fillers, gold, silver, copper and other metals A powder etc. are mentioned.

The primer coating composition (i) has a polymer component which is excellent in the adhesion to both the base material of the resulting coated article and the fluorine-containing layer (B). And a heat-resistant resin are preferable, but from the point that the corrosion resistance and water vapor resistance of the coated article can be further improved, in addition to the fluorine-containing polymer (a) and the heat-resistant resin, further comprising other resins. It may be.

The other resin is not particularly limited, and examples thereof include phenol resin, urea resin, epoxy resin, urethane resin, melamine resin, polyester resin, polyether resin, acrylic resin, acrylic silicone resin, silicone resin, and silicone polyester resin. Can be mentioned. Since the coated article of the present invention is obtained by firing, the other resin is preferably heat resistant.

The said process (1) is a process of forming a primer application layer (Ap) by apply | coating the primer coating composition (i) which consists of a fluoropolymer (a) and a heat resistant resin on a base material. is there.

The application method is not particularly limited, and when the primer coating composition (i) is liquid, for example, spray coating, roll coating, doctor blade coating, dip (immersion) coating, impregnation coating, spin flow Examples thereof include painting and curtain flow coating, and spray coating is particularly preferable. In the case where the primer coating composition (i) is a powder, electrostatic coating, fluid dipping method, rolining method and the like can be mentioned, among which electrostatic coating is preferable.

The said process (1) should just form the said primer application layer (Ap) by apply | coating the said primer coating composition (i) on a base material, and after the said application | coating, process (2) May be fired before or after the coating, or may not be fired. Further, when the primer coating composition (i) is liquid, it is further dried after the coating. It may be a thing or it may not dry.

In the step (1), the drying is preferably performed at a temperature of 70 to 300 ° C. for 5 to 60 minutes. The firing is preferably performed at a temperature of 260 to 410 ° C. for 10 to 30 minutes.

When the primer coating composition (i) is in a liquid state, the step (1) is preferably dried after being applied onto the substrate. Moreover, in order to perform baking of a laminated body in the below-mentioned process (4), it is preferable that baking is not performed.

When the primer coating composition (i) is a powder, the step (1) is preferably performed after being applied onto a substrate.

The primer coating layer (Ap) is formed by coating the primer coating composition (i) on a substrate. The primer coating layer (Ap) may be formed only by the coating in the step (1), or may be formed by drying after the coating. After the above application, it may be formed by baking as necessary after drying. The primer coating layer (Ap) becomes the primer layer (A) in the resulting coated article.

The method for producing a coated article according to the present invention comprises applying a fluorine-containing powder (ii) comprising a melt-processable fluorine-containing polymer (b) and a filler onto a primer coating layer (Ap). The process (2) which forms a coating layer (Bp) is included.

The melt processable fluorine-containing polymer (b) is a polymer having a melt processability among polymers having fluorine atoms directly bonded to carbon atoms constituting the main chain or side chain.

As said melt-processable fluoropolymer (b), what has melt processability among the above-mentioned fluoropolymers (a) can be used. In the melt-processable fluoropolymer (b), the fluorine-containing layer (B) has excellent adhesion between the primer layer (A) and the fluorine-containing layer (C), and the resulting coated article has corrosion resistance and water vapor resistance. From the standpoint of excellent properties, those having a melting point of 150 to 350 ° C. and a melt viscosity at a temperature 50 ° C. higher than the melting point are preferably 10 ⁶ (Pascal · second) or less, and are the above-mentioned TFE copolymer. Is preferred. The melt-processable fluoropolymer (b) may be composed of one or two or more fluoropolymers. The melt-processable fluoropolymer (b) is more preferably at least one fluoropolymer selected from the group consisting of PFA and FEP. The melt-processable fluoropolymer (b) may be either PFA or FEP alone or a mixture thereof. From the viewpoint of excellent heat resistance, the melt-processable fluoropolymer (b) is more preferably PFA. In the present specification, the above-mentioned “filler” is used for the purpose of imparting characteristics, improving physical properties, increasing the amount, etc. to the coated article to be obtained. Examples of the above properties and physical properties include strength, durability, weather resistance, and flame retardancy.

The filler is not particularly limited. For example, wood powder, quartz sand, carbon black, clay, talc, diamond, tourmaline, cocoon, germanium, extender pigment, bright flat pigment, scaly pigment, glass, various reinforcing materials. , Various fillers, conductive fillers and the like. When the coated article of the present invention is required to have a glitter feeling, the filler is preferably a glitter filler. The “brilliant filler” is a filler capable of imparting glitter to the resulting coated article.

Examples of the filler include those classified as bright flat pigments and scaly pigments, glass, and the like, and one or more of these can be used. There are no particular limitations on those classified into the above-mentioned glittering flat pigments and scaly pigments, and examples thereof include mica powder (including those coated with titanium oxide and the like), metal powders, and the like. The glass is not particularly limited, and examples thereof include glass powder such as glass beads, glass bubbles, glass flakes, and glass fibers. Further, glass powder coated with metal such as gold, silver, nickel, etc., glass powder coated with acid value titanium, acid value iron or the like can also be used. One or two or more types can be used as the glass classified into the glittering flat pigment and the scaly pigment and the glass.

As the filler, at least one filler selected from the group consisting of mica powder, metal powder, and glass powder is more preferable. Such a filler may be mica powder, metal powder or glass powder alone, or mica powder, metal powder or glass powder and other fillers that can impart a glitter to the coated article. There may be. The filler may be mica powder alone, metal powder alone, glass powder alone, a mixture of mica powder and metal powder, a mixture of mica powder and glass powder, or a mixture of metal powder and glass powder. .
The filler is preferably 0.001 part by mass or more and 10 parts by mass or less, and 0.01 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the melt-processable fluoropolymer (b). Is more preferable.

The metal powder is not particularly limited, and examples thereof include powders of simple metals such as aluminum, iron, tin, zinc, gold, silver, and copper; powders of alloys such as aluminum alloy and stainless steel. The shape of the metal powder is not particularly limited, and examples thereof include a particulate shape and a flake shape. The flake shape is preferable from the viewpoint of excellent glitter. For example, the shape of the aluminum powder is preferably a flake shape.

The filler is particularly preferably at least one filler selected from the group consisting of mica powder and glass powder because the resulting coated article is excellent in corrosion resistance. The mica powder and glass powder are preferably glitter fillers.

One of the preferred embodiments is that the filler is at least one filler selected from the group consisting of mica powder and aluminum powder from the viewpoint of excellent glitter and economy. More preferably, the mica powder and the aluminum powder are glitter fillers. Examples of such a filler include mica powder alone, aluminum powder alone, or a mixture of mica powder and aluminum powder.

The fluorine-containing powder (ii) is composed of a melt-processable fluorine-containing polymer (b) and a filler. Since the fluorine-containing powder (ii) is a powder, it is easy to obtain a thick coating layer with a small number of coatings.

In the fluorine-containing powder (ii), the particles made of the melt-processable fluorine-containing polymer (b) preferably have an average particle diameter of 0.1 to 50 μm, more preferably 5 to 50 μm. The filler preferably has an average particle size of 0.1 to 600 μm. More preferably, it is 1-600 micrometers, More preferably, it is 5-200 micrometers.
The average particle size of the fluoropolymer (a), the melt-processable fluoropolymers (b) and (c), and the filler is determined by the laser light scattering method (Microtrack particle size analysis, manufactured by Nikkiso Co., Ltd.). Meter, MODEL 9320-HRA type).

The fluorine-containing powder (ii) contains, together with the melt-processable fluorine-containing polymer (b) and the filler, further improving the coating workability and the corrosion resistance and water vapor resistance of the resulting coated article, and the filler. For the purpose of uniformly dispersing in the fluorine layer (B), it may further comprise an additive. The same additive as the additive which can be used for the above-mentioned primer coating composition (i) can be used. The fluorine-containing powder (ii) preferably contains a pigment dispersant for the purpose of dispersing and stabilizing the filler such as a glittering flat pigment.

In the step (2), the fluorine-containing powder coating layer (Bp) is formed by applying the fluorine-containing powder (ii) on the primer coating layer (Ap). The coating method is not particularly limited, and examples thereof include the same method as the coating method when the primer coating composition (i) is a powder, and among these, electrostatic coating is preferable.

In the step (2), the fluorine-containing powder (ii) may be applied to the substrate and then fired. The firing in the step (2) is preferably performed at a temperature of 260 to 410 ° C. for 10 to 30 minutes, as in the firing in the step (1).

Since the above-mentioned fluorine-containing powder (ii) fires the laminate in the step (4) described later, it is preferable that the powder is not usually fired after being coated on the primer coating layer (Ap). .

The fluorine-containing powder coating layer (Bp) is formed by coating the fluorine-containing powder (ii) on the primer coating layer (Ap). In the step (2), the fluorine-containing powder coating layer (Bp) may be formed only by the coating, or may be formed by firing as necessary after the coating. It may be a thing. The fluorine-containing powder coating layer (Bp) becomes the fluorine-containing layer (B) in the resulting coated article.

In the method for producing a coated article according to the present invention, since the filler is well dispersed in the fluorine-containing powder (ii), the filler is uniformly dispersed in the fluorine-containing layer (B) of the resulting coated article. It is possible to stably exhibit characteristics such as glitter feeling.

In the production method of the present invention, a fluorine-containing powder coating layer (Cp) is formed by applying a fluorine-containing powder (iii) comprising a melt-processable fluorine-containing polymer (c) on the fluorine-containing powder layer (Bp). ) Is formed.

The melt processable fluorine-containing polymer (c) has melt processability among polymers having fluorine atoms directly bonded to carbon atoms constituting the main chain or side chain.

As said melt-processable fluoropolymer (c), what has melt processability among the above-mentioned fluoropolymers (a) can be used. The melt processable fluoropolymer (c) is common to the melt processable fluoropolymer (b) in that it has melt processability among the fluoropolymers (a) described above. However, it is different from the above-mentioned melt-processable fluorine-containing polymer (b) in the fluorine-containing layer (B) in that it is in the fluorine-containing layer (C).

The melt-processable fluoropolymer (c) has excellent film-forming properties, the fluorine-containing layer (C) has excellent adhesion to the above-mentioned fluorine-containing layer (B), and the resulting coated article Are the same as the above-mentioned melt-processable fluoropolymer (b) from the viewpoint of excellent corrosion resistance and water vapor resistance. Moreover, what has a melting point of 150-350 degreeC and whose melt viscosity in the temperature 50 degreeC higher than melting | fusing point is 10 < ⁶ > (pascal second) or less is preferable. An example of such a melt-processable fluoropolymer (c) is a TFE copolymer. The melt-processable fluoropolymer (c) is preferably at least one polymer selected from the group consisting of PFA and FEP from the viewpoint of excellent heat resistance, non-adhesiveness and film-forming property. The melt processable fluoropolymer (c) may be PFA alone, FEP alone, or a mixture of PFA and FEP. As the melt-processable fluoropolymer (c), PFA is more preferable from the viewpoint of excellent heat resistance.

In the step (3), a fluorine-containing powder coating layer (Cp) is formed by applying a fluorine-containing powder (iii) made of a melt-processable fluorine-containing polymer (c) on the fluorine-containing powder layer (Bp). ). By using the fluorine-containing powder (iii) made of the melt-processable fluorine-containing polymer (c) on the fluorine-containing powder layer (Bp), it is easy to obtain a thick coating layer with a small number of coatings. Moreover, since the said fluorine-containing layer (C) can be made into a thick layer, the coated article excellent in abrasion resistance can be formed.

The above-mentioned fluorinated powder (iii), together with the melt-processable fluorinated polymer (c), further improves the coating workability and the corrosion resistance and water vapor resistance of the resulting coated article. It may consist of the same additive as the additive that can be used for the coating composition (i).

The melt-processable fluoropolymer (c) preferably has an average particle size of 5 to 50 μm. The minimum with a more preferable average particle diameter of the particle | grains which consist of the said melt-processable fluoropolymer (c) is 10 micrometers, and a more preferable upper limit is 30 micrometers.

In the step (3), the fluorine-containing coating layer (Cp) is formed on the fluorine-containing powder coating layer (Bp) using the melt-processable fluorine-containing composition.

The method for forming the fluorine-containing layer (Cp) comprises applying the melt-processable fluorine-containing composition on the fluorine-containing powder coating layer (Bp). The application method is not particularly limited, and examples thereof include the same method as the application method when the above-described primer coating composition (i) is a powder, among which electrostatic coating is preferable.

The fluorine-containing layer (Cp) is formed by using the melt-processable fluorine-containing composition on the fluorine-containing powder coating layer (Bp). The fluorine-containing layer (Cp) may be formed by firing as necessary after the application, or the fluorine-containing layer (Cp) may be a fluorine-containing layer ( C).

In the production method of the present invention, a base material, a primer coating layer (Ap), a fluorine-containing powder coating layer (Bp), and a laminate comprising the fluorine-containing powder coating layer (Cp) are baked to form a base. A step (4) of forming a coated article comprising a material, a primer layer (A), a fluorine-containing layer (B), and a fluorine-containing layer (C).

The firing in the step (4) is preferably performed at a temperature of 260 to 410 ° C. for 10 to 30 minutes, similarly to the firing in the steps (1) to (3).

In the method for producing a coated article of the present invention, after the step (1) of forming the primer coating layer (Ap) or after the step (2) of forming the fluorine-containing powder coating layer (Bp), characters It may have a step of printing a drawing or the like. The said character, drawing, etc. are the character, line, etc. which show the quantity of water, for example, when a coated article is a rice cooker.

The printing method is not particularly limited, and examples thereof include pad transfer printing. It does not specifically limit as printing ink used for the said printing, For example, the composition which consists of PES, a TFE homopolymer, and a titanium oxide is mentioned.

The present invention is also a coated article obtained by the above production method. In the coated article, a base material, a primer layer (A), a fluorine-containing layer (B), and a fluorine-containing layer (C) are laminated in this order. Usually, the coated article of the present invention is one in which no other layer is interposed between each of the substrate, the primer layer (A), the fluorine-containing layer (B) and the fluorine-containing layer (C). If necessary, another layer is interposed between the primer layer (A) and the fluorine-containing layer (B) or between the fluorine-containing layer (B) and the fluorine-containing layer (C). Also good.

The primer layer (A) is composed of a fluoropolymer (a) and a heat resistant resin.

The primer layer (A) is usually formed on a substrate. The primer layer (A) is formed by applying a primer coating composition (i) described later comprising a fluoropolymer (a) and a heat-resistant resin on a substrate, drying as necessary, and then firing. Can be obtained. The primer layer (A) has a difference in surface tension between the fluoropolymer (a) and the heat-resistant resin, so that the fluoropolymer (a) floats during firing and is far from the substrate. The fluoropolymer (a) is mainly arranged on the surface side at a distance, and the heat-resistant resin is mainly arranged on the substrate side.

Since the said heat resistant resin has adhesiveness with a base material, the said primer layer (A) is excellent in the adhesiveness with respect to a base material. The primer layer (A) is also excellent in adhesion to the fluorine-containing layer (B) because the fluorine-containing polymer (a) has an affinity with the melt-processable fluorine-containing polymer (b). . Thus, the said primer layer (A) has the outstanding adhesiveness with respect to both a base material and a fluorine-containing layer (B).

In the primer layer (A), the PES is preferably 65 to 90% by mass of the total amount of PES and at least one resin selected from the group consisting of PAI and PI, and is preferably 65 to 85%. More preferably, it is mass%.

The primer layer (A) is composed of the fluoropolymer (a) and the heat resistant resin, and the heat resistant resin is a total amount of the heat resistant resin and the fluoropolymer (a). It is preferable that it is 15-50 mass%.

It is preferable that the said primer layer (A) consists of a polymer component and the above-mentioned additive. The primer layer (A) is preferably one in which the polymer component is a fluoropolymer (a) and a heat resistant resin. In the present specification, the “primer layer (A) is a polymer component comprising a fluoropolymer (a) and a heat-resistant resin” means that the polymer in the primer layer (A) is a fluoropolymer (a ) And heat resistant resin only. The primer layer (A) has excellent adhesion to both the base material and the fluorine-containing layer (B) described later, because the polymer component is a fluoropolymer (a) and a heat-resistant resin. It is what you have.

In the primer layer (A), the polymer component is a fluorine-containing polymer (a) and a heat-resistant resin from the viewpoint of having excellent adhesion to both the base material and the fluorine-containing layer (B). Although preferable, the corrosion resistance and water vapor resistance of the coated article can be further improved, and in addition to the fluoropolymer (a) and the heat resistant resin, the coated article may be made of another resin. Examples of other resins include those described above.

The primer layer (A) preferably has a thickness of 5 to 30 μm. If it is less than 5 μm, pinholes are likely to occur, and the corrosion resistance of the coated article may be reduced. If it exceeds 30 μm, cracks are likely to occur, and the steam resistance of the coated article may be reduced. The upper limit with a preferable film thickness of the said primer layer (A) is 20 micrometers.

The coated article of the present invention has a fluorine-containing layer (B) comprising a melt-processable fluorine-containing polymer (b) and a filler.

In the coated article of the present invention, the fluorine-containing layer (B) is laminated on the primer layer (A). The fluorine-containing layer (B) has a fluorine-containing layer (C) described later laminated thereon.

In the said fluorine-containing layer (B), it is preferable that the said filler is 0.001-10 mass% with respect to a melt-processable fluorine-containing polymer (b). When the fluorine-containing layer (B) is made of a filler capable of imparting a glitter feeling, if the filler is less than 0.001% by mass, the glittering feeling of the resulting coated article is not sufficient. When it exceeds mass%, there exists a possibility that corrosion resistance and water vapor resistance may fall. A preferable lower limit of the filler is 0.01% by mass, and a preferable upper limit is 5% by mass.

It is preferable that the said fluorine-containing layer (B) consists of a polymer component, a filler, and the additive mentioned above. The fluorine-containing layer (B) preferably has a polymer component that is a melt-processable fluorine-containing polymer (b). In the present specification, “the fluorine-containing layer (B) has a polymer component that is a melt-processable fluorine-containing polymer (b)” means that the polymer in the fluorine-containing layer (B) is a melt-processable fluorine-containing polymer. It means that it is only a polymer (b). The fluorine-containing layer (B) is superior to both the primer layer (A) and the fluorine-containing layer (C) described later because the polymer component is a melt-processable fluorine-containing polymer (b). It has good adhesion.

The fluorine-containing layer (B) preferably has a thickness of 0.1 to 30 μm. When a filler having a glittering feeling is used to impart a glittering feeling to the coated article, the glittering feeling of the resulting coated article may not be sufficient if it is less than 0.1 μm. If it exceeds 30 μm, cracks are likely to occur in the fluorine-containing layer (B), and the water vapor resistance of the coated article may be reduced. A more preferable lower limit of the film thickness of the fluorine-containing layer (B) is 1 μm, and a more preferable upper limit is 25 μm.

The coated article of the present invention has a fluorine-containing layer (C) composed of a melt-processable fluorine-containing polymer (c).

In the coated article of the present invention, the fluorine-containing layer (C) is formed on the above-mentioned fluorine-containing layer (B). The fluorine-containing layer (C) is a layer formed on the fluorine-containing layer (B), and is fired at a temperature equal to or higher than the melting point of the melt-processable fluorine-containing polymer (c). preferable.

The fluorine-containing layer (C) is preferably a transparent layer when the obtained coated article is required to have design properties such as glitter. When the fluorine-containing layer (C) is a transparent layer, the filler in the fluorine-containing layer (B) can be visually recognized through the fluorine-containing layer (C). When used, the coated article of the present invention has good glitter.

In addition, when the fluorine-containing layer (C) is a transparent layer, the fluorine-containing layer (C) does not have a coloring pigment that is considered to cause a deterioration in corrosion resistance. The article has better corrosion resistance and water vapor resistance.

The fluorine-containing layer (C) is also preferably composed of a polymer component and an additive. The fluorine-containing layer (C) preferably has a polymer component that is a melt-processable fluorine-containing polymer (c). In the present specification, “the fluorine-containing layer (C) has a polymer component that is a melt-processable fluorine-containing polymer (c)” means that the polymer in the fluorine-containing layer (C) is a melt-processable fluorine-containing polymer. It means that it is only a polymer (c). The fluorine-containing layer (C) has excellent adhesion to the fluorine-containing layer (B) because the polymer component is a melt-processable fluorine-containing polymer (c).

The fluorine-containing layer (C) preferably has a thickness of 10 to 90 μm. If it is less than 10 μm, pinholes are likely to occur, and the corrosion resistance and wear resistance of the coated article may be reduced. When it exceeds 90 μm, when the coated article is in the presence of water vapor, the water vapor tends to remain in the coated article, and the water vapor resistance may be poor. The minimum with a more preferable film thickness of the said fluorine-containing layer (C) is 30 micrometers, and a more preferable upper limit is 70 micrometers.
In addition, the film thickness of each said layer can be measured using commercially available film thickness meters, such as a high frequency type film thickness meter.

In the coated article of the present invention, the substrate, the primer layer (A), the fluorine-containing layer (B), and the fluorine-containing layer (C) are laminated in this order. The coated article of the present invention is such that the primer layer (A), the primer layer (A), the fluorine-containing layer (B), and the fluorine-containing layer (C) are laminated in this order. The upper surface of A) and / or the upper surface of the fluorine-containing layer (B) may be printed with characters, drawings and the like.

As described above, the coated article of the present invention only needs to have the primer layer (A), the fluorine-containing layer (B), and the fluorine-containing layer (C), and the fluorine-containing layer (C). A layer may be further provided thereon.

As described above, the coated article of the present invention comprises a fluorine-containing layer (B) formed on a primer layer (A) formed on a substrate and a melt-processable fluorine-containing polymer (b) and a filler. The fluorine-containing layer (C) formed on the fluorine-containing layer (B) is made of a melt-processable fluorine-containing polymer (c).

In the coated article of the present invention, since the melt-processable fluorine-containing polymer (b) and the melt-processable fluorine-containing polymer (c) are both melt-processable, the fluorine-containing layer (B) and the fluorine-containing layer Adhesiveness with (C) is excellent, and it is excellent in corrosion resistance and water vapor resistance. The conventional laminate in which the primer layer, the intermediate layer made of TFE homopolymer, and the topcoat layer made of PFA are laminated in this order has a problem that it is inferior in water vapor resistance. This is considered to be due to easy separation from the intermediate layer. This peeling is caused by differences in thermal expansion coefficient and thermal contraction ratio between TFE homopolymer and PFA, resulting in residual internal stress (strain) in the intermediate layer and topcoat layer, and pinholes. This is considered to occur easily between the primer layer and the intermediate layer. The coated article of the present invention has excellent adhesion between the fluorine-containing layer (B) and the fluorine-containing layer (C) as described above, excellent corrosion resistance and water vapor resistance, and excellent wear resistance. It will be.

Since the coated article of the present invention can uniformly disperse the filler in the fluorine-containing layer (B), it is excellent in glitter when using a filler having glitter. Is. Since the coated article of the present invention is not in contact with the base material, the coated article is excellent in corrosion resistance even when, for example, the above metal powder is used as the filler.

The coated article of the present invention is not particularly limited, and can be used for applications utilizing non-adhesiveness, heat resistance, slipperiness, etc. possessed by the fluoropolymer, for example, using non-adhesiveness, Cooking utensils such as frying pans, pressure cookers, pans, grill pans, rice cookers, ovens, hot plates, baking molds, kitchen knives, gas tables, etc .; Examples of utilizing slipperiness include tools such as saws and files; household items such as irons; metal foils and the like. Especially, it is preferable that they are a rice cooker, a pressure cooker, and a grill pan in which corrosion resistance and steam resistance are requested | required, and it is more preferable that it is a rice cooker in which designability is requested | required.

The method for producing a coated article according to the present invention has the above-described configuration, and is excellent in corrosion resistance, water vapor resistance, and wear resistance, and can stably exhibit the characteristics of a filler such as glitter even during mass production. Coated articles can be produced.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. “%” And “part” represent mass% and mass part, respectively.

Production Example 1 Preparation of Polyethersulfone Resin Aqueous Dispersion 60 parts of a polyethersulfone resin [PES] having a number average molecular weight of about 24,000 and 60 parts of deionized water were completely pulverized in a ceramic ball mill. Stir for about 10 minutes. Subsequently, 180 parts of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) was added, and further pulverized for 48 hours to obtain a dispersion. The obtained dispersion was further pulverized with a sand mill for 1 hour to obtain a PES aqueous dispersion having a PES concentration of about 20%. The average particle diameter of the particles composed of PES in the PES aqueous dispersion was 2 μm.

Production Example 2 Preparation of Polyamideimide Resin Aqueous Dispersion Polyamideimide resin [PAI] varnish (containing 71% NMP) having a solid content of 29% was poured into water to precipitate PAI. This was pulverized for 48 hours in a ball mill to obtain an aqueous PAI dispersion. The solid content of the obtained PAI aqueous dispersion was 20%, and the average particle size of PAI in the PAI aqueous dispersion was 2 μm.

Production Example 3 Preparation of Primer Coating Composition (i) The PES aqueous dispersion obtained in Production Example 1 and the PAI aqueous dispersion obtained in Production Example 2 were mixed with the solid content of PES and PAI. Mixed to 85% of the total amount, tetrafluoroethylene homopolymer [TFE homopolymer] aqueous dispersion (average particle size 0.28 μm, solid content 60%, polyether nonionic interface as dispersant) Active agent (containing 6% of polyoxyethylene tridecyl ether) with respect to the TFE homopolymer) so that the PES and PAI are 20% of the total solid content of the PES, PAI and TFE homopolymer In addition, methylcellulose as a thickener was added in an amount of 0.7% based on the solid content of the TFE homopolymer, and a nonionic surfactant (polyoxyethylene) was added as a dispersion stabilizer. The emissions nonylphenyl ether) was added 6% based on the solids content of the TFE homopolymer, to obtain an aqueous dispersion solids of TFE homopolymer is 34%.

Production Example 4 Preparation of Filler-Containing Powder Coating Composition Tetrafluoroethylene / perfluoro (alkyl vinyl ether) [PFA] powder coating (trade name: ACX-31, Daikin Industries, PFA average particle size 25 μm) As a filler, glass flakes (specific gravity of about 2.5, average particle size of 40 μm; glass flakes coated with titanium dioxide) are added to 0.5% of PFA and mixed to obtain a powder coating composition. It was.

Comparative Production Example 1 Preparation of filler-containing aqueous dispersion Tetrafluoroethylene / perfluoro (alkyl vinyl ether) [PFA] aqueous dispersion (average particle size 0.35 μm, solid content 48%, polyether nonionic as dispersant) Mica powder (specific gravity about 3, average particle size 30 μm; mica coated with titanium dioxide) as a filler in 0.6% of the solid content of PFA % To obtain an aqueous dispersion having a solid content of 48%.

Example After degreasing the surface of an aluminum plate (A-1050P) with acetone, sand blasting was performed so that the surface roughness Ra value measured according to JIS B 1982 was 2.0 to 3.0 μm, and the surface was Roughened. After removing dust on the surface by air blowing, the primer coating composition (i) obtained in Production Example 3 is coated with an RG-2 type gravity spray gun (trade name) so that the dry film thickness is about 10 μm. , Manufactured by Anest Iwata Co., Ltd., nozzle diameter 1.0 mm), and spray-coated at a spraying pressure of 0.2 MPa. The coating layer on the obtained aluminum plate was dried at 80 to 100 ° C. for 15 minutes and cooled to room temperature. On the obtained primer coating layer, the filler-containing powder coating composition obtained in Production Example 4 was applied under the conditions of an applied voltage of 50 kV and a pressure of 0.08 MPa so that the film thickness after firing was about 25 μm. Electrostatic coating with. On top of this, a PFA powder coating (trade name: ACX-31, manufactured by Daikin Industries, PFA average particle size 25 μm) is fired so that the film thickness is about 40 μm, with an applied voltage of 50 kV and a pressure of 0.08 MPa. Electrostatic coating was performed under the conditions, and the resulting unfired laminate was baked at 380 ° C. for 20 minutes to obtain a test coating plate. The obtained test coating plate had a primer layer, a filler-containing layer, and a PFA layer formed on an aluminum plate.

(Evaluation method)
The following evaluation was performed about the coating film of the obtained coating plate for a test.

The film thickness was measured using a high-frequency film thickness meter (trade name: LZ-300C, manufactured by Kett Science Laboratory).

Oden's Elemental Corrosion Resistance Test The surface of the coating film of the obtained test coating plate was scratched to reach the aluminum plate by cross-cutting with a cutter knife. This test coating plate was immersed in a solution of 20 g of oden element (water-soluble powder seasoning; made by Sakai Foods Co., Ltd.) in 1 liter of water, kept at 70 ° C., and there was no abnormality such as generation of blisters. These were visually inspected every 100 hours and tested up to 1000 hours. When there was no abnormality such as the occurrence of blisters, it was accepted, and when there was an abnormality such as the occurrence of blisters, it was rejected.

Steam Resistance Test The obtained test coating plate was left in 0.6 MPa steam for 8 hours, returned to normal pressure, taken out, and then heated at 200 ° C. for 1 minute. This was repeated up to 10 cycles, and the presence or absence of blisters was examined. When no blister was generated in 10 cycles, the test was accepted. When blister was generated by 10 cycles, the test was rejected.

The test coating plates obtained in the examples passed the Oden element corrosion resistance test, and the water vapor resistance test was acceptable with no blistering up to 10 cycles.

On the primer coating layer obtained in Comparative Example, instead of the filler-containing powder coating composition obtained in Production Example 4, the filler-containing aqueous dispersion obtained in Comparative Production Example 1, Spray coating was performed in the same manner as the primer coating composition (i) so that the dry film thickness was about 25 μm. The obtained filler-containing coating layer was dried at 80 to 100 ° C. for 15 minutes and cooled to room temperature. Electrostatic coating of PFA powder paint (trade name: ACX-31, manufactured by Daikin Industries, PFA average particle size 25 μm) on the obtained filler-containing coating layer under the conditions of an applied voltage of 50 kV and a pressure of 0.08 MPa. And it baked at 380 degreeC for 20 minute (s), the PFA layer whose film thickness is about 40 micrometers was formed, the coating plate for a test was produced and evaluated.

The obtained test coating board passed the Oden's elemental corrosion resistance test, but in the steam resistance test, blisters were generated in 3 cycles and failed. Moreover, peeling between the primer layer and the filler-containing layer was visually observed in the blister-generating portion of the test coating plate after performing the water vapor resistance test.

In the example in which the filler-containing layer was formed using the filler-containing PFA powder coating, the obtained test coating plate was excellent in both corrosion resistance and water vapor resistance. In the comparative example in which the filler-containing layer was formed using an aqueous dispersion consisting of the above, the obtained test coating plate was excellent in corrosion resistance, but blisters were generated when left in water vapor, and the water resistance It was inferior to.

Since the method for producing a coated article of the present invention has the above-described configuration, it is possible to obtain a coated article that is excellent in corrosion resistance and water vapor resistance and can stably exhibit the characteristics of a filler such as glitter even during mass production. Can do.

Claims (12)

A step (1) of forming a primer coating layer (Ap) by applying a primer coating composition (i) comprising a fluoropolymer (a) and a heat-resistant resin on a substrate;
A step of forming a fluorine-containing powder coating layer (Bp) by coating a fluorine-containing powder (ii) comprising a melt-processable fluorine-containing polymer (b) and a filler on the primer coating layer (Ap). (2),
A step of forming a fluorine-containing powder coating layer (Cp) by applying a fluorine-containing powder (iii) comprising a melt-processable fluorine-containing polymer (c) on the fluorine-containing powder coating layer (Bp) ( 3) and
By firing a laminate comprising the substrate, the primer coating layer (Ap), the fluorine-containing powder coating layer (Bp), and the fluorine-containing powder coating layer (Cp), the substrate and the primer layer (A) A process for producing a coated article comprising the step (4) of forming a coated article comprising a fluorine-containing layer (B) and a fluorine-containing layer (C). The melt processable fluoropolymer (b) has an average particle diameter of 5 to 50 μm,
The method for producing a coated article according to claim 1, wherein the filler is 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the melt-processable fluoropolymer (b). The heat resistant resin is at least one selected from the group consisting of polyamideimide resin, polyimide resin, polyethersulfone resin, polyetherimide resin, polyetheretherketone resin, aromatic polyester resin, and polyarylene sulfide resin. The method for producing a coated article according to claim 1 or 2, which is a resin. The heat resistant resin comprises a polyethersulfone resin and at least one resin selected from the group consisting of a polyamideimide resin and a polyimide resin,
The polyethersulfone resin is 65 to 90 mass% of the total amount of the polyethersulfone resin and at least one resin selected from the group consisting of the polyamideimide resin and the polyimide resin. A method for producing a coated article. The method for producing a coated article according to claim 1, wherein the heat-resistant resin is 15 to 50% by mass of the total amount of the heat-resistant resin and the fluoropolymer (a). The melt processable fluorine-containing polymer (c) is at least one copolymer selected from the group consisting of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. The method for producing a coated article according to claim 1, 2, 3, 4, or 5, which is a polymer. The fluorine-containing polymer (a) is composed of a tetrafluoroethylene homopolymer, a modified polytetrafluoroethylene, a tetrafluoroethylene / hexafluoropropylene copolymer, and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer. The method for producing a coated article according to claim 1, 2, 3, 4, 5, or 6, wherein the polymer is at least one polymer selected from the above. The melt-processable fluoropolymer (b) is at least one copolymer selected from the group consisting of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. The method for producing a coated article according to claim 1, 2, 3, 4, 5, 6 or 7, which is a polymer. The method for manufacturing a coated article according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the filler is at least one filler selected from the group consisting of mica powder and glass powder. The primer layer (A) has a film thickness of 5 to 30 μm,
The fluorine-containing layer (B) has a thickness of 0.1 to 30 μm,
The method for producing a coated article according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the fluorine-containing layer (C) has a thickness of 10 to 90 µm. Step (1) is a step of forming the primer coating layer (Ap) by applying the primer coating composition (i) and then drying, or applying the primer coating composition (i). The method of manufacturing a coated article according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the primer coating layer (Ap) is formed by drying and firing. A coated article obtained by the manufacturing method according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11 .