JP5967230B2 - Coated article and method for forming corrosion-resistant coating film - Google Patents

Description

The present invention relates to a coated article and a method for forming a corrosion-resistant coating film. More specifically, the present invention relates to a coated article having a layer made of a fluorine-containing polymer and a method for forming a corrosion-resistant coating film.

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.

For the purpose of improving the wear resistance and strength of the layer made of the fluorine-containing polymer, a filler may be added at the time of forming the layer.
For example, a rice cooker is disclosed that includes a fluororesin coat formed on the inner surface of a base material and a pan in which at least either silicon carbide or diamond is unevenly distributed as additive particles on the top coat inner surface layer side of the fluororesin coat. (For example, refer to Patent Document 1).

In addition, a fluororesin coating film having a primer layer, an intermediate coat layer containing PFA, and a top coat layer containing a filler and diamond powder and glass flakes such as PFA is disclosed (for example, patents). Reference 2).

Further, it comprises at least three layers of a primer layer formed on the substrate, an intermediate layer formed on the primer layer, and a topcoat layer formed on the intermediate layer, and each of the intermediate layer and the topcoat layer is at least One kind of hard filler having a new Mohs hardness of 10 or more, and any hard filler contained in the topcoat layer is smaller than the average particle diameter of any hard filler contained in the intermediate layer. A fluororesin laminate having a diameter is disclosed (for example, see Patent Document 3).

JP 2006-15114 A JP 2006-297865 A JP 2011-1116075 A

As a method for forming a coating film having excellent wear resistance, a method of electrostatically coating a fluoropolymer powder coating containing a filler is known. However, it cannot be said that the fluoropolymer and the filler have high affinity. In addition, a voltage is applied to the powder coating material during electrostatic coating. However, since the degree of charging is different between the filler and the fluoropolymer, it is not easy to form a uniform coating film. For these reasons, when the coating film is scratched, the coating film may be peeled off from the substrate or the primer layer due to moisture or the like entering from the scratch. Accordingly, there is a need for a coated article that has excellent wear resistance and at the same time excellent corrosion resistance.

An object of the present invention is to provide a coated article having excellent wear resistance and at the same time excellent corrosion resistance in view of the above-described present situation.

As described above, as a method for forming a coating film having excellent wear resistance, a method of electrostatic coating a powder coating of a fluoropolymer containing a filler is known. The combined powder coating cannot be said to have high fluidity, and electrostatic coating is not easy. Therefore, a method for easily forming a coating film by electrostatic coating has also been demanded.

An object of the present invention is to provide a corrosion-resistant coating film that can form a coating film that is excellent in wear resistance and at the same time excellent in corrosion resistance, and that can be easily formed by electrostatic coating. There is also providing a forming method.

The present inventors use a fluoropolymer powder coating containing a filler when coating the surface of a substrate with a plurality of layers, and the number of fluoropolymer particles and the particles of the filler It was found that a coated article having unexpectedly excellent wear resistance and at the same time excellent corrosion resistance can be obtained by setting the number of these to a specific ratio, and the present invention has been completed.

That is, the present invention provides a substrate,
A primer layer (A) comprising a fluoropolymer (a) and a heat-resistant resin,
A fluorine-containing layer (B) formed from the powder coating material (I), and
A fluorine-containing layer (C) formed from the powder paint (II),
A coated article having
The powder coating material (I) contains particles of the melt processable fluoropolymer (b) and particles of the filler (i), and has 100 particles of the melt processable fluoropolymer (b). The number of particles of the filler (i) is 0.0001 to 30.0,
The powder coating material (II) includes particles of the melt-processable fluoropolymer (c) and particles of the filler (ii), and has 100 particles of the melt-processable fluoropolymer (c). In contrast, the coated article is characterized in that the number of particles of the filler (ii) is 0.0001 to 30.0.

The filler (i) is preferably at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes.

The filler (ii) is preferably at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes.

The filler (i) and the filler (ii) are preferably of different types.

The melt processable fluoropolymer (b) is at least one selected from the group consisting of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. Is preferred.

The melt-processable fluoropolymer (b) preferably has an average particle diameter of 1 to 50 μm.

The melt-processable fluoropolymer (c) is at least one selected from the group consisting of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. Is preferred.

The melt-processable fluoropolymer (c) preferably has an average particle size of 1 to 50 μm.

The fluoropolymer (a) is selected from the group consisting of a tetrafluoroethylene homopolymer, a modified polytetrafluoroethylene, a tetrafluoroethylene / hexafluoropropylene copolymer, and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer. It is preferable that at least one selected.

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. Preferably there is.

The heat-resistant resin is a polyethersulfone resin and one or both of a polyamideimide resin and a polyimide resin, and the polyethersulfone resin is a total of the polyethersulfone resin, the polyamideimide resin and the polyimide resin. It is preferable that it is 65-85 mass% of quantity.

The heat resistant resin is preferably 15 to 50% by mass of the total solid content of the heat resistant resin and the fluoropolymer (a).

The primer layer (A) has a thickness of 5 to 30 μm, the fluorine-containing layer (B) has a thickness of 1 to 90 μm, and the fluorine-containing layer (C) has a thickness of 1 to 90 μm. It is preferable that

Further, the inventors of the present invention surprisingly use a powder coating material in which a filler is mixed in a predetermined number ratio when electrostatically coating a coating film on a primer layer provided on the surface of a substrate. In addition, it was found that a corrosion-resistant coating film having excellent wear resistance and at the same time excellent corrosion resistance was obtained, and the present invention was completed.

That is, according to the present invention, the melt-processable fluoropolymer particles and the filler particles have a number of filler particles of 0.0001 to 30.0 with respect to 100 melt-processable fluoropolymer particles. A step of preparing a powder coating by mixing so that it becomes an individual, and
It is also a method for forming a corrosion-resistant coating film, comprising a step of applying the powder coating material onto a primer layer provided on a substrate by electrostatic coating to form a corrosion-resistant coating film (R1).

It is preferable that the forming method further includes a step of forming the corrosion-resistant coating film (R2) by applying the powder coating material onto the corrosion-resistant coating film (R1) by electrostatic coating.

Since the coated article of the present invention has the above-described configuration, it has excellent wear resistance and also has corrosion resistance. Such a coated article can be particularly suitably used for cooking utensils and kitchen utensils. Further, according to the method for forming a corrosion-resistant coating film of the present invention, by having the above-described configuration, it is possible to form a coating film having excellent wear resistance and at the same time excellent corrosion resistance, and electrostatic coating. Thus, a coating film can be easily formed. Such a method for forming a corrosion-resistant coating film can be particularly suitably used for the production of cooking utensils, kitchen utensils and the like.

The present invention is described in detail below.

<Coated article>
The coated article of the present invention has a substrate, a primer layer (A), a fluorine-containing layer (B), and a fluorine-containing layer (C). Among these, the fluorine-containing layer (B) is melt-processable fluorine-containing heavy. The fluorine-containing layer (C) is formed of a powder paint (I) containing particles of the coalescence (b) and particles of the filler (i), and the fluorine-containing layer (C) comprises particles of the melt-processable fluorine-containing polymer (c) and the filler ( It is formed from the powder coating material (II) containing the particle | grains of ii).

The number of particles of the filler (i) in the powder coating material (I) is 0.0001 to 30.0 with respect to 100 particles of the melt-processable fluoropolymer (b). The number of particles of the filler (ii) in the body paint (II) is 0.0001 to 30.0 with respect to 100 particles of the melt-processable fluoropolymer (c).

Thus, the coated article of the present invention has a substrate, a primer layer (A), a fluorine-containing layer (B), and a fluorine-containing layer (C), and also includes a fluorine-containing layer (B) and a fluorine-containing layer (C ), The number of particles of the filler contained in the powder coating is adjusted, so that the wear resistance and the corrosion resistance are excellent.

The coated article of the present invention comprises a substrate, a primer layer (A) formed on the substrate, a fluorine-containing layer (B) formed on the primer layer (A), and the fluorine-containing layer (B). It is preferable to have the fluorine-containing layer (C) formed in the above.

Hereinafter, the coated article of the present invention will be described in more detail with specific examples.

The substrate constituting the coated article of the present invention is not particularly limited, and examples thereof include metals such as iron, aluminum and copper and metals such as alloys thereof; nonmetallic inorganic materials such as enamel, glass and ceramics. Can be mentioned. 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. The said surface treatment can apply | coat the coating composition for primers for forming the said primer layer (A) uniformly, without producing repellency, and the point which the adhesiveness of a base material and a primer layer improves From the above, it may be appropriately selected according to the type of the base material, the primer coating composition, etc., but for example, sandblast is preferred.

The primer layer (A) constituting the coated article of the present invention is composed of a fluoropolymer (a) and a heat resistant resin.

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 (a1).

The above “fluorinated monoethylenically unsaturated hydrocarbon (a1)” (hereinafter also referred to as “unsaturated hydrocarbon (a1)”) means vinyl in which part or all of the hydrogen atoms are substituted by fluorine atoms. An unsaturated hydrocarbon having one group in the molecule is meant.

In the unsaturated hydrocarbon (a1), 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 (a1) excludes trifluoroethylene described later.

The unsaturated hydrocarbon (a1) is not particularly limited. For example, tetrafluoroethylene [TFE], hexafluoropropylene [HFP], chlorotrifluoroethylene [CTFE], vinylidene fluoride [VdF], 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 (a1). Examples of the homopolymer of the unsaturated hydrocarbon (a1) include tetrafluoroethylene homopolymer [TFE homopolymer], polychlorotrifluoroethylene [PCTFE], polyvinylidene fluoride [PVdF], and polyvinyl fluoride [PVF]. ] Etc. are mentioned. TFE homopolymer is non-melt processable.

The fluoropolymer (a) is also a copolymer of at least one unsaturated hydrocarbon (a1) and an unsaturated compound (a2) that can be copolymerized with the unsaturated hydrocarbon (a1). It may be. That is, the unsaturated compound (a2) is different from the unsaturated hydrocarbon (a1).

The unsaturated compound (a2) 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 also be a copolymer of two or more unsaturated hydrocarbons (a1). The copolymer of the two or more unsaturated hydrocarbons (a1) and the copolymer of the at least one unsaturated hydrocarbon (a1) and the unsaturated compound (a2) 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 (a3) that can be copolymerized with the following TFE. The other monomer (a3) 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), and 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]. As PFA, PFA fluorinated by the method described in WO 2002/088227 pamphlet can also be used.

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 hydrocarbon (a1), and 3FH among the unsaturated compound (a2). Among other monomers (a3), 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 fluoropolymer (a) may be one type or two or more types, and is a copolymer of the unsaturated hydrocarbon (a1) homopolymer and the unsaturated hydrocarbon (a1). Or a mixture of two or more of the above-mentioned unsaturated hydrocarbon (a1) 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) is also a perfluoroalkyl group-containing ethylenically unsaturated monomer (a4) having a perfluoroalkyl group (hereinafter also referred to as “unsaturated monomer (a4)”). It may be obtained by polymerizing. The unsaturated monomer (a4) 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 (a4), or the unsaturated monomer (a4) and the unsaturated monomer (a4). ) And a copolymer with the monomer (a5) that can be copolymerized.

The monomer (a5) is not particularly limited, and examples thereof include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, polyethylene glycol di (meth) acrylate, N-methylolpropane acrylamide, (meth) acrylic. (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 ynoic acid; 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. Polymers are 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 fluoropolymer (a), in the obtained coated article, a polymer containing a TFE copolymer is preferable from the viewpoint of excellent adhesion between the primer layer (A) and the fluorine-containing layer (B). . 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 fluoropolymer (a) containing a TFE copolymer include TFE homopolymer alone, PFA alone, a mixture of TFE homopolymer and FEP, a mixture of TFE homopolymer and PFA, and 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. , TFE homopolymer alone, PFA alone, a mixture of TFE homopolymer and PFA, or a mixture of TFE homopolymer and FEP, preferably a TFE homopolymer alone or a mixture of TFE homopolymer and FEP. More preferably.

The heat-resistant resin that can constitute the primer layer (A) is usually a resin that is 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.

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 general 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.

When the heat-resistant resin is composed of PES and one or both of PAI and PI, the PES is 65 to 85% by mass of the total amount of the PES and PAI and PI. Is preferred. More preferably, it is 70-80 mass%.

As content of the said heat resistant resin, it is preferable that it is 10-50 mass% of solid content total amount of this heat resistant resin and the said fluoropolymer (a), and it is more preferable that it is 10-40 mass%. Preferably, it is 15-30 mass%, and it is especially preferable. In the present specification, the “solid content” means a solid at 20 ° C. In the present specification, the above-mentioned “total amount of solid content of the heat-resistant resin and the fluoropolymer (a)” is applied at a temperature of 80 to 100 ° C. after the primer coating composition is applied on a substrate. The total mass of the heat-resistant resin and the fluoropolymer (a) in the residue after baking at 380 to 400 ° C. for 45 minutes is meant.

The primer layer (A) is usually formed on a substrate. For the primer layer (A), for example, a primer coating composition, which will be described later, composed of a fluoropolymer (a) and a heat-resistant resin is applied onto a substrate, dried as necessary, and then fired. Is obtained. The primer layer (A) thus obtained has a difference in surface tension between the fluoropolymer (a) and the heat-resistant resin, so that the fluoropolymer (a) floats during firing. The fluoropolymer (a) is mainly disposed on the surface side at a distance from the substrate, and the heat-resistant resin is mainly disposed on the substrate side.

Since the primer layer (A) is composed of the fluoropolymer (a) and the heat-resistant resin, the heat-resistant resin has adhesiveness to the substrate, and therefore has excellent adhesion to the substrate. . 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, since the said primer layer (A) consists of the said fluoropolymer (a) and the said heat resistant resin, it has the outstanding adhesiveness with respect to both a base material and a fluorine-containing layer (B). Is.

It is preferable that the said primer layer (A) consists of a polymer component and the additive mentioned later. 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 has it efficiently.

The primer layer (A) is composed of a fluorine-containing polymer (a) and a heat-resistant resin from the viewpoint of efficiently exhibiting excellent adhesion to both the base material and the fluorine-containing layer (B). Some are preferred, but in addition to the fluorine-containing polymer (a) and the heat-resistant resin, the coated article may further comprise other resins from the viewpoint that the corrosion resistance and water vapor resistance of the coated article can be further improved. . Examples of other resins include those described later.

The primer layer (A) preferably has a thickness of 5 to 30 μm. If the film thickness is too thin, pinholes are likely to occur, and the corrosion resistance of the coated article may be reduced. If the film thickness is too thick, cracks are likely to occur, and the steam resistance of the coated article may be reduced. The minimum with more preferable film thickness of the said primer layer (A) is 7 micrometers, and an upper limit is 25 micrometers.

As the melt processable fluorine-containing polymer (b) constituting the fluorine-containing layer (B), those having melt processability among the above-mentioned fluorine-containing polymers (a) can be used. In the melt-processable fluoropolymer (b), the resulting 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 In view of excellent water vapor resistance, those having a melting point of 150 to 350 ° C. and a melt viscosity at a temperature 50 ° C. higher than the melting point of 10 ⁶ (pascal · second) or less are preferable. Preferably there is. The melt-processable fluoropolymer (b) may be one type or two or more types. 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.

The fluorine-containing layer (B) is preferably laminated on the primer layer (A). Moreover, it is preferable that the below-mentioned fluorine-containing layer (C) is laminated | stacked on the said fluorine-containing layer (B).

The fluorine-containing layer (B) is formed from a powder coating (I) containing particles of a melt-processable fluorine-containing polymer (b) and particles of a filler (i). If it is a powder paint, unlike a liquid paint such as a water-based paint, a drying process is not required, it is easy to obtain a thick coating film with a small number of coatings, and excellent wear resistance.

The number of particles of the filler (i) in the powder coating material (I) is 0.0001 to 30.0 with respect to 100 particles of the melt-processable fluoropolymer (b).
The preferred lower limit is 0.0005, the more preferred lower limit is 0.001, the still more preferred lower limit is 0.005, and the still more preferred lower limit is 0.01, particularly preferred. The lower limit is 0.1, and the most preferable lower limit is 1. The preferred upper limit is 28, the more preferred upper limit is 25, the still more preferred upper limit is 20, and the particularly preferred upper limit is 15.

The filler (i) is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica, glass flake, zirconium oxide, aluminum nitride, and boron nitride. Preferably, it is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes, and consists of silicon carbide, alumina and diamond. More preferably, it is at least one selected from the group. When the powder coating material (I) contains such a filler, the wear resistance and corrosion resistance of the coated article are further improved.

Fluorinated diamond can be obtained by fluorinating diamond. The fluorination of diamond can be performed, for example, by a known method disclosed in Summary of the 26th Fluorine Chemistry Discussion Meeting, issued on November 14, 2002, p24-25. That is, diamond may be sealed in a reactor made of a material having corrosion resistance to fluorine, such as nickel or an alloy containing nickel, and fluorinated by introducing fluorine gas.

The melt-processable fluoropolymer (b) preferably has an average particle diameter of 1 to 50 μm, more preferably 3 to 40 μm, still more preferably 5 to 30 μm, from the viewpoint of electrostatic coating properties.

The filler (i) preferably has an average particle diameter of 0.01 to 100 μm, more preferably 0.05 to 50 μm, and still more preferably 0.1 to 40 μm, from the viewpoint of electrostatic coating properties.

It is preferable that the said filler (i) is 0.01-40 mass% with respect to the total amount of a melt-processable fluoropolymer (b) and a filler (i). More preferably, it is 0.05-30 mass%, More preferably, it is 0.1-10 mass%. If the amount of the filler (i) is too large, the corrosion resistance is lowered, and if the amount of the filler (i) is too small, sufficient wear resistance cannot be obtained.

The powder coating (I) for forming the fluorine-containing layer (B) is further made of wood powder, quartz sand, carbon black, clay, talc, corundum, quartzite, tourmaline, cocoon, germanium, silica powder, chrysoberyl , Beryl, garnet, garnet, zirconium carbide, tantalum carbide, titanium carbide, tungsten carbide, extender pigment, glittering flat pigment, scaly pigment, glass, various reinforcing materials, various fillers, conductive filler, etc. .

The fluorine-containing layer (B) preferably has a thickness of 1 to 90 μm. If the film thickness is too thin, the resulting coated article may not have sufficient wear resistance. If the film thickness is too thick, it is difficult for water that has permeated from the fluorine-containing layer (B) to escape, and the steam resistance of the coated article may decrease. The more preferable lower limit of the film thickness of the fluorine-containing layer (B) is 5 μm, and the more preferable upper limit is 80 μm.

As the melt-processable fluorine-containing polymer (c) constituting the fluorine-containing layer (C), among the above-mentioned fluorine-containing polymers (a), those having melt processability can be used.

As the above-mentioned melt-processable fluoropolymer (c), it is possible to obtain a film having excellent film-forming properties, a point that the resulting fluorine-containing layer (C) is excellent in adhesion to the above-described fluorine-containing layer (B), and the like. From the viewpoint that the coated article is excellent in wear resistance, the same type as the above-mentioned melt-processable fluoropolymer (b) is preferable. 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 coated article of the present invention, the fluorine-containing layer (C) is preferably formed on the fluorine-containing layer (B) and fired at a temperature equal to or higher than the melting point of the melt-processable fluorine-containing polymer (c). It is preferred that

The fluorine-containing layer (C) is formed from a powder coating (II) containing particles of a melt-processable fluorine-containing polymer (c) and particles of a filler (ii). In the case of a powder coating, unlike a liquid coating such as a water-based coating, it is easy to obtain a thick coating film with a small number of coatings without requiring a drying process, and excellent in wear resistance.

The number of particles of the filler (ii) in the powder coating material (II) is 0.0001 to 30.0 with respect to 100 particles of the melt-processable fluoropolymer (c).
A preferred lower limit is 0.0005, a more preferred lower limit is 0.001, and a still more preferred lower limit is 0.005. The preferred upper limit is 28, the more preferred upper limit is 25, the still more preferred upper limit is 20, and the still more preferred upper limit is 15.

The filler (ii) is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes, zirconium oxide, aluminum nitride and boron nitride. Is preferable, and at least one selected from the group consisting of silicon carbide, alumina, and diamond is more preferable. When the powder coating material (II) contains such a filler, the wear resistance and corrosion resistance of the coated article are further improved.

The filler (i) and the filler (ii) may be the same or different, but from the viewpoint of the design properties of the coating film, the filler (i) and the filler (ii) Are preferably of different types.

The powder coating material (II) may contain a filler (iii) separately from the filler (ii) for the purpose of imparting properties to the coated article to be obtained, improving physical properties, and increasing the amount. Examples of the above properties and physical properties include strength, durability, weather resistance, flame resistance, and design properties. When what has a glittering feeling is used as a filler, the coated article of this invention has a favorable glittering feeling.

The filler (iii) is not particularly limited. For example, wood powder, quartz sand, carbon black, clay, talc, corundum, quartzite, boron nitride, fused alumina, tourmaline, straw, germanium, silica powder, chrysoberyl, Examples include beryl, garnet, garnet, zirconium carbide, tantalum carbide, titanium carbide, tungsten carbide, extender pigment, glittering flat pigment, scaly pigment, glass, metal powder, various reinforcing materials, various extenders, and conductive fillers. It is done. 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.

The melt-processable fluoropolymer (c) preferably has an average particle diameter of 1 to 50 μm, more preferably 3 to 40 μm, still more preferably 5 to 30 μm, from the viewpoint of electrostatic coating properties.

The filler (ii) preferably has an average particle diameter of 0.01 to 100 μm, more preferably 0.05 to 50 μm, and still more preferably 0.1 to 40 μm, from the viewpoint of electrostatic coating properties.

The said filler (ii) is 0.01-40 mass% with respect to the total amount of a melt-processable fluoropolymer (c) and a filler (ii). Preferably it is 0.05-30 mass%, More preferably, it is 0.1-10 mass%. If the amount of the filler (ii) is too large, the corrosion resistance decreases, and if the amount of the filler (ii) is too small, sufficient wear resistance cannot be obtained.

The fluorine-containing layer (C) preferably has a thickness of 1 to 90 μm. If the film thickness is too thin, the corrosion resistance of the coated article may be reduced. If the film thickness is too thick, 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. A more preferable lower limit of the film thickness of the fluorine-containing layer (C) is 5 μm, and a more preferable upper limit is 80 μm.

In the coated article of the present invention, both the fluorine-containing layer (B) and the fluorine-containing layer (C) contain a filler, and the number of particles thereof is appropriately adjusted. It also has excellent corrosion resistance.

The primer layer (A) has a thickness of 5 to 30 μm, the fluorine-containing layer (B) has a thickness of 1 to 90 μm, and the fluorine-containing layer (C) has a thickness of 1 to 90 μm. Some are one of the preferred embodiments of the present invention.

The order of lamination of each layer constituting the coated article of the present invention is not particularly limited, but the substrate, the primer layer (A), the fluorine-containing layer (B), and the fluorine-containing layer (C) are laminated in this order. It is preferable that Thereby, both wear resistance and corrosion resistance can be more effectively achieved.
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.

In the coated article of the present invention, when the substrate, the primer layer (A), the fluorine-containing layer (B), and the fluorine-containing layer (C) are laminated in this order, the upper surface of the primer layer (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). Although a layer may be further provided thereon, the fluorine-containing layer (C) is preferably the outermost layer. By placing the fluorine-containing layer (C), which greatly contributes to the improvement of wear resistance, in the outermost layer that is particularly required to have wear resistance under the usage environment, the effect related to wear resistance of the present invention can be exhibited more remarkably. can do.

The coated article of the present invention is, for example, a step (1) of forming a primer coating film (Ap) by applying a primer coating composition (i) on a substrate, on the primer coating film (Ap), A step (2) of forming a coating film (Bp) by applying a powder paint (I) containing particles of the melt-processable fluoropolymer (b) and particles of the filler (i); Step (3) of forming a coating film (Cp) by applying a powder coating (II) containing particles of melt-processable fluoropolymer (c) and filler (ii) on Bp) And baking the coating film laminate comprising the primer coating film (Ap), the coating film (Bp), and the coating film (Cp), the base material, the primer layer (A), the fluorine-containing layer (B), and the One that includes the step (4) of forming a coated article comprising the fluorine layer (C) Accordingly, it is possible to manufacture.

The number of particles of the filler (i) in the powder coating (I) is 0.0001 to 30.0 with respect to 100 particles of the melt-processable fluoropolymer (b). The number of particles of the filler (ii) in (II) is 0.0001 to 30.0 with respect to 100 particles of the melt-processable fluoropolymer (c).

The said process (1) is a process of forming a primer coating film (Ap) by apply | coating the primer coating composition (i) on a base material.

In the step (1), the primer coating composition (i) is preferably composed of a fluoropolymer (a) and a heat resistant resin. The fluorine-containing polymer (a) and the heat resistant resin are as described above. 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. As said organic liquid, a conventionally well-known organic solvent etc. may be used, 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, and 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. A conventionally known surfactant may be used as the surfactant. In the said primer coating composition (i), the said organic liquid can also be used together with the said surfactant for the purpose of carrying out the dispersion stabilization of the particle | grains which consist of a fluoropolymer (a).

The primer coating composition (i) may also be an organosol obtained by the method described in JP-B-49-17017.

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 environmental problems.

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 an additive mentioned above.

From the point which can improve the corrosion resistance and water vapor resistance of the coated article, the primer coating composition (i) is composed of the fluorine-containing polymer (a) and the heat-resistant resin, as well as other resins described above. It may be.

The method for applying the primer coating composition (i) on the substrate is not particularly limited, and when the primer coating composition (i) is liquid, for example, spray coating, roll coating, or doctor blade coating. Dip (immersion) coating, impregnation coating, spin flow coating, curtain flow coating, and the like, 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.

After application of the primer coating composition (i) in the step (1), baking may be performed before performing the step (2), or baking may not be performed. Moreover, when the said coating composition (i) for primers is liquid, after the said application | coating, it may dry further and does not need to 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, in the step (1), it is preferable to dry after coating on the substrate. Moreover, since baking of a coating film laminated body is performed in the below-mentioned process (4), it is preferable not to perform baking.

When the primer coating composition (i) is a powder, in the step (1), it is preferable to perform baking after coating on the substrate.

The primer coating film is formed by applying the primer coating composition (i) on a substrate and then drying or baking as necessary. The primer coating film becomes a primer layer in the resulting coated article.

In the step (2), a powder coating (I) containing particles of the melt-processable fluoropolymer (b) and particles of the filler (i) is applied on the primer coating film (Ap). This is a step of forming a coating film (Bp).

The powder coating material (I) includes particles of a melt-processable fluoropolymer (b) and particles of a filler (i). If it is a powder paint, unlike a liquid paint such as a water-based paint, a drying process is not required, it is easy to obtain a thick coating film with a small number of coatings, and excellent wear resistance.

The number of particles of the filler (i) is 0.0001 to 30.0 with respect to 100 particles of the melt processable fluoropolymer (b).
The preferred lower limit is 0.0005, the more preferred lower limit is 0.001, the still more preferred lower limit is 0.005, and the still more preferred lower limit is 0.01, particularly preferred. The lower limit is 0.1, and the most preferable lower limit is 1. The preferred upper limit is 28, the more preferred upper limit is 25, the still more preferred upper limit is 20, and the particularly preferred upper limit is 15.

From the viewpoint of electrostatic coating properties, the average particle diameter of the melt-processable fluoropolymer (b) is preferably 1 to 50 μm, more preferably 3 to 40 μm, and 5 to 30 μm. More preferably it is.

The average particle diameter of the filler (i) is preferably 0.01 to 100 μm, more preferably 0.05 to 50 μm, and still more preferably 0.1 to 40 μm from the viewpoint of electrostatic coating properties.

The filler (i) is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica, glass flake, zirconium oxide, aluminum nitride, and boron nitride. Preferably, it is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes, and consists of silicon carbide, alumina and diamond. More preferably, it is at least one selected from the group. When the powder coating material (I) contains such a filler, the wear resistance and corrosion resistance of the coated article are further improved. The powder coating (I) is further made of wood powder, quartz sand, carbon black, clay, talc, corundum, quartzite, tourmaline, coral, germanium, silica powder, chrysoberyl, beryl, garnet, garnet, zirconium carbide, carbonized Tantalum, titanium carbide, tungsten carbide, extender pigments, bright flat pigments, scaly pigments, glass, various reinforcing materials, various fillers, conductive fillers, and the like may be included.

The powder coating material (I) may also contain a small amount of PTFE (TFE homopolymer, modified PTFE) together with the melt-processable fluoropolymer (b) for the purpose of refining the spherulites. In this case, the content of PTFE is preferably 0.01 to 10.0% by mass with respect to PFA.

The method for applying the powder coating material (I) onto the primer coating film is not particularly limited, and examples thereof include electrostatic coating, fluid dipping, and rotrining, among which electrostatic coating is preferable.

In the said process (2), after apply | coating powder coating material (I) on a base material, you may bake. The firing in the step (2) is preferably performed under the same conditions as the firing in the step (1).

Usually, it is preferable not to perform baking after applying the powder coating (I) onto the primer coating film. This is because all the coating films can be fired at the same time when firing the coating film laminate in the step (4) described below.

The coating film (Bp) is formed by applying the powder paint (I) on the primer coating film and then baking it as necessary. The coating film (Bp) becomes a fluorine-containing layer (B) in the resulting coated article.

In the step (3), the coating film (Bp) is coated with a powder coating (II) containing particles of the melt-processable fluoropolymer (c) and filler (ii). This is a step of forming (Cp).

The powder coating material (II) in the step (3) includes particles of the melt-processable fluoropolymer (c) and particles of the filler (ii). If it is a powder paint, unlike a liquid paint such as a water-based paint, a drying process is not required, it is easy to obtain a thick coating film with a small number of coatings, and excellent wear resistance.

The number of particles of the filler (ii) is 0.0001 to 30.0 with respect to 100 particles of the melt processable fluoropolymer (c).
A preferred lower limit is 0.0005, a more preferred lower limit is 0.001, and a still more preferred lower limit is 0.005. The preferred upper limit is 28, the more preferred upper limit is 25, the still more preferred upper limit is 20, and the still more preferred upper limit is 15.

From the viewpoint of electrostatic coating properties, the average particle diameter of the melt-processable fluoropolymer (c) is preferably 1 to 50 μm, more preferably 3 to 40 μm, and 5 to 30 μm. More preferably it is.

The filler (ii) preferably has an average particle size of 0.01 to 100 μm, more preferably 0.05 to 50 μm, still more preferably 0.1 to 40 μm.

The filler (ii) is preferably at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes, silicon carbide, alumina and More preferably, it is at least one selected from the group consisting of diamond. When the powder coating material (II) contains such a filler, the wear resistance and corrosion resistance of the coated article are further improved.

The filler (i) and the filler (ii) may be the same or different, but from the viewpoint of the design properties of the coating film, the filler (i) and the filler (ii) Are preferably of different types.

The powder coating material (II) may contain other fillers for the purpose of imparting properties to the resulting coated article, improving physical properties, increasing the amount, and the like. Examples of the above properties and physical properties include strength, durability, weather resistance, flame resistance, and design properties. Examples of the filler include those described above.

The powder coating material (II) may also contain a small amount of PTFE (TFE homopolymer, modified PTFE) together with the melt-processable fluoropolymer (c) for the purpose of refining the spherulites. In this case, the content of PTFE is preferably 0.01 to 10.0% by mass with respect to PFA.

Moreover, it is preferable that the said powder coating material (II) does not contain a color pigment. Since colored pigments are generally considered to cause deterioration of corrosion resistance, if the powder paint (II) does not contain color pigments, the resulting coated article has better corrosion resistance and water vapor resistance. It will have.

The method for applying the powder coating material (II) on the coating film (Bp) is not particularly limited, and for example, electrostatic coating is preferable.

The coating film (Cp) may be formed by firing after the coating as necessary. The firing in the step (3) is preferably performed under the same conditions as the firing in the step (1). The coating film (Cp) becomes a fluorine-containing layer (C) in the obtained coated article.

In the step (4), the base film, the primer layer (A), and the fluorine-containing layer (the layer containing the primer coating film (Ap), the coating film (Bp), and the coating film (Cp) are baked. This is a step of forming a coated article comprising B) and a fluorine-containing layer (C).

The firing in the step (4) is preferably performed under the same conditions as the firing in the steps (1) to (3).

The said manufacturing method has the process of printing a character, drawing, etc. after the process (1) which forms the said primer coating film (Ap), or the process (2) which forms the said coating film (Bp). It may be a thing. 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.

<Method for forming corrosion-resistant coating film>
In the method of forming a corrosion-resistant coating film of the present invention, the melt-processable fluoropolymer particles and the filler particles have a number of filler particles of 0.1 relative to 100 melt-processable fluoropolymer particles. A step of preparing a powder coating by mixing so as to become 0001 to 30.0, and
It includes a step of applying the powder coating material onto a primer layer provided on a substrate by electrostatic coating to form a corrosion-resistant coating film (R1).
By this method, it is possible to form a coating film having excellent wear resistance and at the same time excellent corrosion resistance, and it is possible to easily form a corrosion-resistant coating film by electrostatic coating. Moreover, the formation method of the corrosion-resistant coating film of this invention is used suitably for manufacture of the above-mentioned coated article of this invention.

The primer layer can be obtained, for example, by applying a primer coating composition on a substrate (film formation step (1)). The primer coating composition is preferably composed of a fluoropolymer (a) and a heat resistant resin. The fluorine-containing polymer (a) and the heat resistant resin are as described above. The primer coating composition may be liquid or powder. When the primer coating composition is in a liquid state, it comprises 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 is mainly composed of an organic liquid, the heat-resistant resin and the fluoropolymer (a) are dispersed as particles in the liquid medium and / or It is dissolved in a liquid medium. As said organic liquid, a conventionally well-known organic solvent etc. may be used, may be used independently, and may use 2 or more types together.

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

When the liquid medium is mainly composed of water, the primer coating composition is usually added with a surfactant for the purpose of dispersing and stabilizing the particles composed of the fluoropolymer (a). It will be. A conventionally known surfactant may be used as the surfactant. In the said primer coating composition, the said organic liquid can also be used together with the said surfactant for the purpose of carrying out the dispersion | distribution stabilization of the particle | grains which consist of a fluoropolymer (a).

The primer coating composition may also be an organosol obtained by the method described in JP-B-49-17017.

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

The primer coating composition is further described above for the purpose of further improving the coating workability and the corrosion resistance and water vapor resistance of the resulting corrosion resistant coating film together with the fluoropolymer (a) and the heat resistant resin. It may consist of an additive.

The primer coating composition is composed of the fluoropolymer (a) and the heat-resistant resin, as well as the other resins described above, from the viewpoint of further improving the corrosion resistance and water vapor resistance of the corrosion-resistant coating film. It may be.

The method for applying the primer coating composition on the substrate is not particularly limited, and when the primer coating composition is liquid, for example, spray coating, roll coating, doctor blade coating, dip coating , Impregnation coating, spin flow coating, curtain flow coating, and the like. Among these, spray coating is preferable. In the case where the primer coating composition is a powder, electrostatic coating, fluid dipping method, rolining method and the like can be mentioned, among which electrostatic coating is preferable.

After application of the primer coating composition in the film forming step (1), baking may be performed before the film forming step (2) described later, or may not be performed. Moreover, when the said coating composition for primers is liquid, after the said application | coating, it may dry further and does not need to dry.

In the film forming 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 is in a liquid state, in the film forming step (1), it is preferable to dry after coating on the substrate.

When the primer coating composition is a powder, in the film forming step (1), it is preferable to perform baking after coating on the substrate. However, as will be described later, when the entire coating film is finally fired, the firing may not be performed at this point.

The primer layer is formed by applying the primer coating composition on a substrate and then drying or baking as necessary. The primer coating film becomes a primer layer in the resulting corrosion-resistant coating film.

The method for forming a corrosion-resistant coating film according to the present invention includes a melting process as a process for preparing a powder coating material suitable for forming a coating film by electrostatic coating on a primer layer provided on such a substrate. The particles of the processable fluoropolymer and the filler particles are mixed with 100 particles of the melt processable fluoropolymer so that the number of filler particles is 0.0001 to 30.0. Process. And the said powder coating material is apply | coated by electrostatic coating on the primer layer provided on the base material as mentioned above, and a corrosion-resistant coating film (R1) is formed (film-forming process (2)). Moreover, the said powder coating material is apply | coated by electrostatic coating on the said corrosion-resistant coating film (R1) further as needed, and a corrosion-resistant coating film (R2) is formed (film-forming process (3)).

By using a powder paint, unlike a liquid paint such as a water-based paint, a drying process is unnecessary, and it is easy to obtain a thick coating film with a small number of coatings, and excellent wear resistance. However, when electrostatic coating is applied to the powder coating, it cannot be said that the fluoropolymer powder coating containing the filler has high fluidity and electrostatic coating is not easy. However, as a result of the study by the present inventors, it is possible to form a uniform coating film when the number of filler particles satisfies a certain range with respect to the number of the melt-processable fluoropolymer particles as described above. Thus, it was found that a corrosion-resistant coating film having excellent wear resistance and excellent corrosion resistance can be obtained.

In the step of preparing the powder coating material, the melt-processable fluoropolymer particles and the filler particles have a number of filler particles of 0.1 relative to 100 melt-processable fluoropolymer particles. Mix so as to be 000 1-30.0.
A preferred lower limit is 0.0005, a more preferred lower limit is 0.001, and a still more preferred lower limit is 0.005. The preferred upper limit is 28, the more preferred upper limit is 25, and the still more preferred upper limit is 20.

As the powder coating for forming the corrosion-resistant coating film (R1), the powder coating (I) containing the filler (i) is preferably used. As the powder coating for forming the corrosion-resistant coating film (R2), the powder coating (II) containing the filler (ii) is preferably used.

The process for forming the corrosion-resistant coating film (R1) (film formation process (2)) and the process for forming the corrosion-resistant coating film (R2) (film formation process (3)) will be described in detail below. .

In the film forming step (2), the powder coating is applied onto the primer layer by electrostatic coating to form a corrosion-resistant coating film (R1).

The average particle diameter of the melt-processable fluoropolymer particles contained in the powder coating used in the film-forming step (2) is preferably 1 to 50 μm from the viewpoint of electrostatic coating properties. 40 micrometers is more preferable and 5-30 micrometers is still more preferable.

The filler contained in the powder coating used in the film forming step (2) preferably has an average particle diameter of 0.01 to 100 μm, more preferably 0.05 to 50 μm, from the viewpoint of electrostatic coating properties. Preferably, 0.1 to 40 μm is more preferable.

The filler contained in the powder coating used in the film forming step (2) is silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flake, zirconium oxide, aluminum nitride and boron nitride. It is preferably at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes. Is more preferable, and at least one selected from the group consisting of silicon carbide, alumina, and diamond is even more preferable. When the powder coating material contains the filler, the wear resistance and wear resistance of the corrosion-resistant coating film are further improved.

The powder coating used in the film forming step (2) further includes wood powder, quartz sand, carbon black, clay, talc, corundum, quartzite, tourmaline, straw, germanium, silica powder, chrysoberyl, beryl, garnet, It may contain garnet, zirconium carbide, tantalum carbide, titanium carbide, tungsten carbide, extender pigment, glittering flat pigment, scaly pigment, glass, various reinforcing materials, various extenders, conductive fillers, and the like.

The powder coating material used in the film forming step (2) may also contain a small amount of PTFE (TFE homopolymer, modified PTFE) together with the melt-processable fluoropolymer for the purpose of refining the spherulites. In this case, the content of PTFE is preferably 0.01 to 10.0% by mass with respect to PFA.

In the film forming step (2), the powder coating material may be applied to the primer layer and then fired. The firing in the film forming step (2) is preferably performed under the same conditions as the firing in the film forming step (1).

However, as will be described later, when the entire coating film is finally fired, all the coating films can be fired at the same time. Therefore, when the powder coating material is applied onto the primer layer, no firing is performed. May be. The obtained coating film becomes a corrosion-resistant coating film (R1).

In the method for forming a corrosion-resistant coating film of the present invention, it is preferable that a film forming step (3) is further included after the film forming step (2). The film forming step (3) is a step of forming the corrosion-resistant coating film (R2) by applying the powder coating on the corrosion-resistant coating film (R1) by electrostatic coating.

The average particle diameter of the melt-processable fluoropolymer particles contained in the powder coating used in the film-forming step (3) is preferably 1 to 50 μm from the viewpoint of electrostatic coating properties. 40 micrometers is more preferable and 5-30 micrometers is still more preferable.

The filler contained in the powder coating used in the film formation step (3) preferably has an average particle diameter of 0.01 to 100 μm, more preferably 0.05 to 50 μm, from the viewpoint of electrostatic coating properties. Preferably, 0.1 to 40 μm is more preferable.

The filler contained in the powder coating used in the film forming step (3) is silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes, zirconium oxide, aluminum nitride and boron nitride. It is preferably at least one selected from the group consisting of, and more preferably at least one selected from the group consisting of silicon carbide, alumina, and diamond. When the powder coating material contains the filler, the wear resistance and wear resistance of the corrosion-resistant coating film are further improved.

The powder coating material used in the film forming step (3) may contain other fillers for the purpose of imparting characteristics to the resulting corrosion-resistant coating film, improving physical properties, and increasing the amount. Examples of the above properties and physical properties include strength, durability, weather resistance, flame resistance, and design properties.

Such fillers include wood powder, quartz sand, carbon black, clay, talc, corundum, quartzite, boron nitride, fused alumina, tourmaline, straw, germanium, silica powder, chrysoberyl, beryl, garnet, garnet, Examples thereof include zirconium carbide, tantalum carbide, titanium carbide, tungsten carbide, extender pigments, bright flat pigments, scaly pigments, glass, metal powder, various reinforcing materials, various extenders, and conductive fillers. When the formed corrosion-resistant coating film is required to have a glitter feeling, a glitter filler is preferred. The “brilliant filler” is a filler that can impart a glitter feeling to the resulting corrosion-resistant coating film.

The powder coating material used in the film forming step (3) may also contain a small amount of PTFE (TFE homopolymer, modified PTFE) together with the melt-processable fluoropolymer for the purpose of refining the spherulites. In this case, the content of PTFE is preferably 0.01 to 10.0% by mass with respect to PFA.

Moreover, it is preferable that the powder coating material used at the said film-forming process (3) does not contain a color pigment. Since the color pigment can cause the corrosion resistance to deteriorate, the powder paint does not contain the color pigment, and thus the resulting corrosion-resistant coating film has more excellent corrosion resistance and water vapor resistance.

In the film forming step (3), the powder coating material may be applied to the corrosion-resistant coating film (R1) and then baked. The firing in the film forming step (3) is preferably performed under the same conditions as the firing in the film forming step (1) or (2). The obtained coating film becomes a corrosion-resistant coating film (R2).

After the film forming steps (1) to (3), the entire coating film may be baked. That is, the method for forming a corrosion-resistant coating film according to the present invention includes the film-forming step (1) for forming the corrosion-resistant coating film (R1) or the step (2) for forming the corrosion-resistant coating film (R2). After that, a baking step may be further included. It is preferable to perform the said baking process on the conditions similar to the baking in the said film-forming process (1)-(3).

The forming method includes a film forming step (1) for forming the corrosion-resistant coating film (R1), a film forming step (2) for forming the corrosion-resistant coating film (R2), or a character after the baking step. 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 the said corrosion-resistant coating film is applied to 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 coated article of the present invention or the corrosion-resistant coating film formed by the method for forming a corrosion-resistant coating film of the present invention should be used for applications utilizing the non-adhesiveness, heat resistance, slipperiness, etc. of the fluoropolymer. For example, cooking equipment such as frying pan, pressure cooker, pan, grill pan, rice cooker, oven, hot plate, baking mold, kitchen knife, gas table; electric pot, ice tray, Kitchen articles such as molds and range hoods; parts for the food industry such as kneading rolls, rolling rolls, conveyors, hoppers; office automation (OA) rolls, OA belts, OA separation nails, paper rolls, film production calendars Industrial goods such as rolls; Molds for molding foamed polystyrene, molds, molds such as molds, mold release plates for plywood and decorative board production, industrial containers (especially semiconductors) For industrial use), tools that use slipperiness, such as saws, files, etc .; household items such as irons, scissors, knives; metal foils, electric wires, food processing machines, packaging machines, textile machinery, etc. Examples include bearings, sliding parts for cameras and watches, pipes, valves, automotive parts such as bearings, snow shovels, plows, and chutes.
Among these, it can be suitably used for cooking utensils and kitchen utensils, and can be particularly suitably used for rice cookers.

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 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. Next, 180 parts of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) was added to obtain an aqueous PES 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 A polyamideimide resin [PAI] varnish (containing 71% NMP) having a solid content of 29% was poured into water and pulverized in a ball mill to obtain a PAI aqueous 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. Mix to 75% of the total amount, and add tetrafluoroethylene homopolymer [TFE homopolymer] aqueous dispersion (average particle size 0.28 μm, solid content 60%, polyether nonionic interface as dispersant) Active agent (polyoxyethylene tridecyl ether) 6% with respect to the TFE homopolymer) so that the PES and PAI are 25% 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 a 34% solids aqueous dispersion of TFE homopolymer.

Example 1
After degreasing the surface of the aluminum plate (A-1050P) with acetone, sand blasting is performed so that the surface roughness Ra value measured according to JIS B 1982 is 2.0 to 3.0 μm, and the surface is roughened. Turned into. After removing dust on the surface by air blowing, the coating composition for primer (i) obtained in Production Example 3 was sprayed at a pressure of 0.2 MPa using a gravity spray gun so that the dry film thickness was 10 μm. Spray painted with. The obtained coating film on the aluminum plate was dried at 80 to 100 ° C. for 15 minutes and cooled to room temperature. On the obtained primer coating film, PFA (trade name: ACX-21, manufactured by Daikin Industries, average particle size 23 μm) and silicon carbide as a filler (average particle size 15 μm, total amount of PFA and silicon carbide) 2%) was electrostatically 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 40 μm. On top of that, PFA and diamond as a filler (average particle size 18 μm, 1% of the total amount of PFA and diamond) are applied voltage 50 KV, pressure 0.08 MPa so that the film thickness after firing is 5 μm. Electrostatic coating was applied under the conditions of The obtained coated plate was baked at 380 ° C. for 20 minutes to obtain a test coated plate. The obtained test coating plate was obtained by forming a primer layer, an intermediate coating layer, and a top coating layer on an aluminum plate.

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

(Calculation of particle number ratio (number ratio))
The number of particles was calculated by the following formula.
w = d × 4/3 × (circumferential ratio) × ((average particle diameter) / 2) ³
w: Weight of one particle d: Specific gravity of fluorine-containing resin or filler

The ratio of the number of particles (number ratio) X, where w1 is the weight of one fluororesin particle determined by the above formula, w2 is the weight of one filler particle, and F wt% is the amount of filler. Was calculated by the following formula.
X = (F / w2) / ((100−F) / w1) × 100

(Measurement of repose angle, evaluation of paintability)
In order to investigate the fluidity of the powder paint, the angle of repose was measured by the following method. 100 g of powder coating material was dropped from a funnel (the upper part had a diameter of 8 cm and the lower outlet had a diameter of 1 cm), and the angle of repose of the powder coating deposited on the lower part was measured with a protractor. The better the fluidity of the powder paint, the smaller the angle of repose of the deposited powder paint, and the better the paintability.
When the repose angle was 43 ° or less, the paintability was good (◯).
When the angle of repose was 44 ° or more, the paintability was poor (x). This indicates that the flow rate of the powder coating is unstable.

(Abrasion amount)
The abrasion resistance of the obtained test coating plate was measured using a rotary ablation tester manufactured by Toyo Seiki Co., Ltd. under a load of 1 kg and a wear wheel CS-10 under conditions of 500 revolutions.

(Corrosion resistance)
Two scratches reaching the base material having a length of 50 mm were crossed on the coating film surface of the obtained test coating plate (50 mm × 100 mm, thickness 2.5 mm) with a cutter knife (cross cut). This test plate is immersed in a solution of 20 g of Oden element (manufactured by Sakai Foods Co., Ltd.) in 1 liter of water, kept at 70 ° C., and after 500 hours, blistering (blowing of the coating film) occurs. It was confirmed that there was no abnormality.
○: No blisters △: Blisters of less than 3 mm occur in the crosscut part (no abnormality other than the crosscut part)
×: Blister occurs on the entire surface

Examples 2-7
Examples 2 to 7 were the same as Example 1 except that powder coatings containing the fillers shown in Table 1 in the amounts shown in Table 1 were used as powder coatings in the intermediate coating process instead of silicon carbide. A coated plate for test was obtained. About the obtained coating plate for a test, the coating-film physical property was evaluated similarly to Example 1.

Comparative Examples 1-3
The powder coating material containing the filler shown in Table 2 in the amount shown in Table 2 was used as the powder coating material in the intermediate coating step, and the filler shown in Table 2 was used as the powder coating material in the top coating step. The test coating plates of Comparative Examples 1 to 3 were obtained in the same manner as in Example 1 except that the powder coating contained in the amount shown in FIG. About the obtained coating plate for a test, the coating-film physical property was evaluated similarly to Example 1.

Comparative Example 4
Example except that no filler was added as a powder coating in the intermediate coating step, and a powder coating containing the filler shown in Table 2 in the amount shown in Table 2 was used as the powder coating in the top coating step. In the same manner as in No. 1, a test coating plate was obtained. About the obtained coating plate for a test, the coating-film physical property was evaluated similarly to Example 1.

The evaluation results of the test coating plates obtained in Examples 1 to 7 are shown in Table 1, and the evaluation results of the test coating plates obtained in Comparative Examples 1 to 4 are shown in Table 2.

Since the coated article of the present invention has the above-described configuration, it is excellent in both wear resistance and corrosion resistance, and can be particularly suitably used for coated articles such as cooking utensils and kitchen utensils.

Claims (10)

A coated article used for cooking utensils or kitchen utensils,
Base material,
A primer layer (A) comprising a fluoropolymer (a) and a heat-resistant resin,
A fluorine-containing layer (B) formed from the powder coating material (I), and
A fluorine-containing layer (C) formed from the powder paint (II),
I have a,
The powder coating (I) includes particles of the melt processable fluoropolymer (b) and particles of the filler (i), and the particles of the melt processable fluoropolymer (b) are: The average particle size is 5 to 30 μm, the particles of the filler (i) have an average particle size of 0.1 to 40 μm, and the filler is 100 particles of the melt-processable fluoropolymer (b). The number of particles of (i) is 1 to 15, and the filler (i) is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, and glass flakes. And
The powder coating (II) includes particles of the melt processable fluoropolymer (c) and particles of the filler (ii), and the particles of the melt processable fluoropolymer (c) are: The average particle size is 5 to 30 μm, the filler (ii) particles have an average particle size of 0.1 to 40 μm, and the filler is 100 particles of the melt-processable fluoropolymer (c). the number of particles (ii) is Ri 0.005 Kodea,
A coated article , wherein the filler (i) and the filler (ii) are of different types . The coated article according to claim 1, wherein the filler (ii) is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, mica and glass flakes. The melt-processable fluoropolymer (b) is at least one selected from the group consisting of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. 3. The coated article according to 1 or 2 . The melt processable fluoropolymer (c) is at least one selected from the group consisting of a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer and a tetrafluoroethylene / hexafluoropropylene copolymer. The coated article according to 1, 2 or 3 . The fluoropolymer (a) is selected from the group consisting of a tetrafluoroethylene homopolymer, a modified polytetrafluoroethylene, a tetrafluoroethylene / hexafluoropropylene copolymer, and a tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer. The coated article according to claim 1, 2, 3 or 4 , wherein the coated article is at least one kind. 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 coated article according to claim 1, 2, 3, 4 or 5 . The heat-resistant resin is a polyethersulfone resin and one or both of a polyamideimide resin and a polyimide resin, and the polyethersulfone resin is a total amount of the polyethersulfone resin, the polyamideimide resin and the polyimide resin. The coated article according to claim 1, 2, 3, 4, 5 or 6 . The coated article according to claim 1, 2, 3, 4, 5, 6 or 7 , wherein the heat resistant resin is 15 to 50% by mass of the total solid content of the heat resistant resin and the fluoropolymer (a). The primer layer (A) has a film thickness of 5 to 30 μm,
The fluorine-containing layer (B) has a thickness of 1 to 90 μm,
The coated article according to claim 1, 2, 3, 4, 5, 6, 7 or 8 , wherein the fluorine-containing layer (C) has a thickness of 1 to 90 µm. A method of forming a corrosion-resistant coating film used for cooking utensils or kitchen utensils,
And particles of the particle and the filler of the melt-processable fluoropolymer (b) (i), the number of particles of the filler (i) with respect to 100 particles of melt-processible fluoropolymer (b) 1 A step of preparing a powder coating material (I) by mixing so as to be ~ 15 ;
Applying the powder coating (I) onto a primer layer provided on a substrate by electrostatic coating to form a corrosion-resistant coating film (R1) ;
The number of particles of the filler (ii) is 0 with respect to 100 particles of the melt processable fluoropolymer (c), and the particles of the melt processable fluoropolymer (c) and the filler (ii). A step of preparing a powder coating material (II) by mixing so as to have 0.005 to 15 pieces, and
It was applied by electrostatic coating on the powder coating material (II) corrosion resistance coating (R1), seen including a step <br/> of forming a corrosion resistant coating film (R2),
The particles of the melt-processable fluoropolymer (b) have an average particle size of 5 to 30 μm, and the particles of the filler (i) have an average particle size of 0.1 to 40 μm,
The particles of the melt-processable fluoropolymer (c) have an average particle size of 5 to 30 μm, the particles of the filler (ii) have an average particle size of 0.1 to 40 μm,
The filler (i) is at least one selected from the group consisting of silicon carbide, boron carbide, silicon nitride, alumina, diamond, fluorinated diamond, and glass flakes,
A method for forming a corrosion-resistant coating film, wherein the filler (i) and the filler (ii) are of different types .