Composition and coated film

Abstract

The present invention provides a composition and a coating film, the composition providing a coating film which is excellent in adhesion to a substrate and in non-stickiness. A composition characterized by comprising a fluororesin, a heat-resistant resin, water, and a solvent having a boiling point of 205°C or higher.

Description

[0001] This application is a divisional application, which targets the Chinese national application number 201880014949.3, the international application number PCT / JP2018 / 006713, the application date of which was February 23, 2018, the entry date into China of which was August 30, 2019, and the invention title of which is "Composition and Coating". Technical Field

[0002] This invention relates to compositions and coatings. Background Technology

[0003] For cooking utensils such as frying pans, heating plates, pots, and inner pots of rice cookers, in order to prevent the cooking materials from charring or sticking during heating, a coating made of fluororesin with excellent heat resistance, non-stick properties, and stain resistance is usually applied to a metal substrate such as aluminum or stainless steel.

[0004] Patent Document 1 discloses a fluoropolymer coating composition, characterized in that it is formed by dispersing at least three components, namely polyarylene sulfide resin, polyamide-imide resin and / or polyimide resin, and fluoropolymer resin, in a liquid medium.

[0005] Patent Document 2 discloses an aqueous composition for the vulcanization of fluororubber, comprising fluororubber, fluororesin, vulcanizing agent, and at least one additive selected from the group consisting of a surfactant whose decomposition residue after heating at 300°C for 30 minutes is less than 0.3% by weight and a polar solvent having a boiling point below 300°C and a surface tension of more than 30 dyne / cm at room temperature.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 53-74532

[0009] Patent Document 2: International Publication No. 00 / 53675 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, existing technologies cannot fully balance the adhesion between the coating and the substrate, as well as the non-stick properties of the coating.

[0012] In view of the above, the object of the present invention is to provide a composition and the coating film that provide excellent adhesion to the substrate and excellent non-stick properties.

[0013] Methods for solving problems

[0014] The inventors discovered that the above-mentioned problems can be successfully solved by using solvents with boiling points within a specific range, thus completing the present invention.

[0015] That is, the present invention relates to a composition characterized in that it comprises a fluoropolymer, a heat-resistant resin, water, and a solvent having a boiling point of 205°C or higher.

[0016] The preferred mass ratio of the fluoropolymer to the heat-resistant resin is 1 / 99 to 40 / 60.

[0017] The total amount of the above-mentioned fluororesin and the above-mentioned heat-resistant resin is preferably 20% to 50% by mass relative to the total amount of the above-mentioned fluororesin, the above-mentioned heat-resistant resin, the above-mentioned water and the above-mentioned solvent.

[0018] The content of the solvent is preferably 5% to 50% by mass relative to the total amount of the fluororesin, the heat-resistant resin, the water, and the solvent.

[0019] The fluororesin mentioned above is preferably a melt-processable fluororesin.

[0020] The heat-resistant resins mentioned above are preferably polyarylene sulfides or polyethersulfones.

[0021] The heat-resistant resins mentioned above are preferably polyarylene sulfides or polyethersulfones and polyamide imides.

[0022] The solvent is preferably selected from at least one group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, diethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, and 1,4-butanediol.

[0023] The above composition is preferably a coating.

[0024] The above composition is preferably a coating for a single coating layer.

[0025] The present invention also relates to a coating film formed from the above composition.

[0026] The present invention also relates to a cooking utensil having the above-described coating.

[0027] The present invention also relates to a rice cooker having an inner pot having the above-mentioned coating.

[0028] The present invention also relates to a coating film, characterized in that it is formed from a composition comprising water, a fluoropolymer, and a heat-resistant resin, and that its adhesion to rice cake, as determined by a rice cake adhesion test, is 20.0 g / cm. 2 the following.

[0029] The result of the above-mentioned preferred checkerboard pattern test for the coating film is 100 / 100.

[0030] The present invention also relates to a laminate having a substrate and the coating formed on the substrate.

[0031] The effects of the invention

[0032] Because of the above-described structure, the composition of the present invention can be directly applied to a substrate, resulting in a coating film with excellent adhesion to the substrate and excellent non-stick properties. Therefore, the coating composition of the present invention is useful as a single-coat coating.

[0033] Because the coating of the present invention has the above-described structure, it adheres firmly to the substrate and exhibits excellent non-stick properties when formed on a substrate. Even when the laminate is composed of only the coating and the substrate, the two layers adhere firmly and can form a laminate with excellent non-stick properties. Attached Figure Description

[0034] Figure 1 This is a diagram schematically illustrating the method for testing the adhesiveness of rice cakes. Detailed Implementation

[0035] The present invention will now be described in detail.

[0036] The composition of the present invention is characterized in that it contains a solvent with a boiling point of 205°C or higher, thereby enabling the formation of a coating film with excellent adhesion to the substrate and excellent non-stick properties.

[0037] The solvent described above needs to have a boiling point of 205°C or higher. If the boiling point of the solvent is too low, it may be impossible to form a coating film with excellent non-stick properties. The boiling point is preferably 220°C or higher, more preferably 235°C or higher, and even more preferably 265°C or higher. Alternatively, the boiling point can be 300°C or lower.

[0038] The boiling points mentioned above were measured at 1 atm.

[0039] When using two or more solvents, it is acceptable as long as at least one of the solvents has a boiling point of 205°C or higher.

[0040] The solvent described above preferably has a surface tension of 25 dyn / cm or more. If the surface tension of the solvent is within the above range, a coating film with superior non-stick properties can be formed. More preferably, the surface tension is 35 dyn / cm or more, and even more preferably 44 dyn / cm or more. Furthermore, the surface tension is preferably 72 dyn / cm or less.

[0041] The surface tension described above can be measured using methods such as the plate method, ring method, and pendant drop method. It should be noted that the surface tension values ​​mentioned above are for solvents at a temperature of 20°C.

[0042] The solvent is preferably selected from at least one of the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, diethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, and 1,4-butanediol; more preferably, it is selected from at least one of the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, tripropylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and polyethylene glycol dimethyl ether. Furthermore, at least one of the following groups is preferred: triethylene glycol, tetraethylene glycol, glycerin, triethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and polyethylene glycol dimethyl ether. Particularly preferred is at least one of the following groups: triethylene glycol, tetraethylene glycol, and glycerin.

[0043] In the above composition, relative to the total amount of the fluororesin, heat-resistant resin, water, and solvent constituting the composition, the content of the solvent is preferably 5% to 50% by mass, more preferably 10% by mass or more, even more preferably 15% by mass or more, more preferably 40% by mass or less, and even more preferably 30% by mass or less. If the content of the solvent is within the above range, a coating film with better adhesion to the substrate and better non-stick properties can be formed.

[0044] The compositions of the present invention are further characterized in that they comprise a fluoropolymer. The fluoropolymer is a polymer having fluorine atoms directly bonded to carbon atoms constituting the main chain or side chain.

[0045] The aforementioned fluoropolymer preferably possesses melt processability. If the fluoropolymer possesses melt processability, a coating film with superior non-stick properties can be formed. "Melt processability" refers to the ability to melt and process the polymer using existing processing equipment such as extruders and injection molding machines. Therefore, the aforementioned fluoropolymer typically has a melt flow rate (MFR) of 0.01 g / 10 min to 100 g / 10 min.

[0046] In this specification, the MFR mentioned above is the value measured as follows: according to ASTM D 1238, using a melt flow index tester (manufactured by Yasuda Seiki Co., Ltd.), at a test temperature determined according to the type of fluoropolymer (e.g., 372°C in the case of PFA or FEP, and 297°C in the case of ETFE), under a load (e.g., 5 kg in the case of PFA, FEP, and ETFE), the mass of polymer flowing out of a nozzle with an inner diameter of 2 mm and a length of 8 mm every 10 minutes (g / 10 minutes) is measured, and the obtained value is taken as the MFR.

[0047] The melting point of the above-mentioned fluoropolymer is preferably 100℃ to 333℃, more preferably 140℃ or higher, even more preferably 160℃ or higher, particularly preferably 180℃ or higher, and even more preferably 332℃ or lower.

[0048] In this specification, the melting point of the fluoropolymer is the temperature corresponding to the maximum value in the heat of melting curve when heated at a rate of 10°C / min using a differential scanning calorimeter [DSC].

[0049] Examples of the aforementioned fluoropolymers include low molecular weight polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE) / perfluoro(alkyl vinyl ether) (PAVE) copolymer (PFA), TFE / hexafluoropropylene (HFP) copolymer (FEP), ethylene (Et) / TFE copolymer (ETFE), Et / TFE / HFP copolymer, polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene (CTFE) / TFE copolymer, Et / CTFE copolymer, and polyvinylidene fluoride (PVDF), preferably at least one of the group consisting of PFA and FEP, more preferably FEP.

[0050] The aforementioned low molecular weight PTFE refers to PTFE with a number average molecular weight of less than 600,000. "High molecular weight PTFE" with a number average molecular weight exceeding 600,000 is non-melt processable and exhibits the fibrillation characteristics unique to PTFE (for example, see Japanese Patent Application Publication No. 10-147617).

[0051] The aforementioned low molecular weight PTFE can be modified polytetrafluoroethylene (hereinafter also referred to as "modified PTFE") or homopolymer polytetrafluoroethylene (hereinafter also referred to as "homogeneous PTFE").

[0052] The modified PTFE mentioned above is a modified PTFE formed from tetrafluoroethylene (TFE) and monomers other than TFE (hereinafter also referred to as "modified monomers").

[0053] As for the aforementioned modified monomers, there are no particular limitations as long as they can copolymerize with TFE. Examples include perfluoroolefins such as hexafluoropropylene (HFP); chlorofluoroolefins such as trifluorochloroethylene (CTFE); hydrofluoroolefins such as trifluoroethylene and vinylidene fluoride (VDF); perfluorovinyl ethers; perfluoroalkyl ethylene; and ethylene. In addition, the modified monomers used can be one or more.

[0054] There are no particular limitations on the perfluorovinyl ethers mentioned above; for example, perfluorounsaturated compounds represented by the following general formula (1) can be cited.

[0055] CF2 = CF - ORf (1)

[0056] (Where Rf represents a perfluorinated organic group). In this specification, the term "perfluorinated organic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. The aforementioned perfluorinated organic group may have an ether oxygen atom.

[0057] Examples of perfluorovinyl ethers include perfluoro(alkylvinyl ethers) (PAVE) in which Rf is a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 5.

[0058] Examples of perfluoroalkyl groups in the aforementioned PAVE include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, and perfluorohexyl, with perfluoropropyl being the preferred perfluoroalkyl group. That is, the aforementioned PAVE is preferably perfluoropropyl vinyl ether (PPVE).

[0059] As for the aforementioned perfluorovinyl ethers, further examples include substances in the above general formula (1) where Rf is a perfluoro(alkoxyalkyl) compound with 4 to 9 carbon atoms, and Rf is derived from the following formula:

[0060] [Chemistry 1]

[0061]

[0062] (where m represents 0 or an integer from 1 to 4) represents the substance of the group; Rf is the substance represented by the following formula

[0063] [Chemistry 2]

[0064]

[0065] (where n represents an integer from 1 to 4) refers to substances containing groups; etc.

[0066] There is no particular limitation on perfluoroalkyl ethylene (PFAE), for example, perfluorobutyl ethylene (PFBE) and perfluorohexyl ethylene can be mentioned.

[0067] The modifying monomer in the above-mentioned modified PTFE is preferably at least one selected from the group consisting of HFP, CTFE, VDF, PAVE, PFAE and ethylene. PAVE is more preferred, and PPVE is even more preferred.

[0068] The aforementioned homopolymer PTFE essentially contains only TFE units, and is preferably a homopolymer obtained without the use of modified monomers.

[0069] In the above-mentioned modified PTFE, the modified monomer unit is preferably 0.001 mol% to 2 mol%, more preferably 0.001 mol% to 1 mol%.

[0070] In this specification, the content of each monomer constituting PTFE can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescence X-ray analysis according to the type of monomer.

[0071] The PFA is not particularly limited, but preferably a copolymer with a TFE unit to PAVE unit molar ratio (TFE unit / PAVE unit) of 70 / 30 or more and less than 99 / 1. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and a further preferred molar ratio is 80 / 20 or more and 98.9 / 1.1 or less. If there are too few TFE units, the mechanical properties tend to decrease; if there are too many TFE units, the melting point becomes too high and the moldability tends to decrease. The PFA is also preferably a copolymer derived from monomers capable of copolymerizing with TFE and PAVE in which the monomer units are 0.1 mol% to 10 mol%, and the total TFE and PAVE units are 90 mol% to 99.9 mol%. Examples of monomers capable of copolymerizing with TFE and PAVE include HFP and CZ. 3 Z 4 =CZ 5 (CF2) n Z 6 (where Z) 3 Z 4 and Z 5 Same or different, indicating hydrogen or fluorine atoms, Z 6 Vinyl monomers represented by (where n represents an integer from 2 to 10, indicating hydrogen, fluorine, or chlorine atoms) and those derived from CF2=CF-OCH2-Rf 7 (where Rf) 7 Alkyl perfluorovinyl ether derivatives, etc., representing perfluoroalkyl groups with 1 to 5 carbon atoms.

[0072] The melting point of the PFA is preferably 180°C to less than 322°C, more preferably 230°C to 320°C, and even more preferably 280°C to 320°C.

[0073] The melt flow rate (MFR) of the above-mentioned PFA is preferably 1 g / 10 min to 100 g / 10 min.

[0074] The thermal decomposition initiation temperature of the aforementioned PFA is preferably 380°C or higher. More preferably, it is 400°C or higher, and even more preferably 410°C or higher.

[0075] In this specification, the thermal decomposition initiation temperature is defined as follows: using a differential thermal / thermogravimetric analyzer [TG-DTA] (trade name: TG / DTA6200, manufactured by SEIKO Electronics Co., Ltd.), a 10 mg sample is heated from room temperature at a heating rate of 10 °C / min, and the temperature at which the sample decreases by 1% by mass is defined as the thermal decomposition initiation temperature.

[0076] The FEP described above is not particularly limited, but preferably a copolymer with a TFE unit to HFP unit molar ratio (TFE unit / HFP unit) of 70 / 30 or more and less than 99 / 1. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and a further preferred molar ratio is 80 / 20 or more and 98.9 / 1.1 or less. If there are too few TFE units, the mechanical properties tend to decrease; if there are too many TFE units, the melting point becomes too high and the moldability tends to decrease. The FEP described above is also preferably a copolymer derived from monomers capable of copolymerizing with TFE and HFP, where the monomer units are 0.1 mol% to 10 mol%, and the total TFE and HFP units are 90 mol% to 99.9 mol%. Examples of monomers capable of copolymerizing with TFE and HFP include PAVE and alkyl perfluorovinyl ether derivatives.

[0077] The melting point of the above-mentioned FEP is preferably 150℃ to less than 322℃, more preferably 200℃ to 320℃, and even more preferably 240℃ to 320℃.

[0078] The preferred MFR for the above-mentioned FEP is 1g / 10 minutes to 100g / 10 minutes.

[0079] The thermal decomposition initiation temperature of the aforementioned FEP is preferably 360°C or higher. More preferably, it is 380°C or higher, and even more preferably, it is 390°C or higher.

[0080] The content of each monomer unit of the above-mentioned fluoropolymer can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescence X-ray analysis according to the type of monomer.

[0081] The composition of the present invention is further characterized in that it further comprises a heat-resistant resin (excluding the aforementioned fluororesin).

[0082] The optimal continuous operating temperature for the aforementioned heat-resistant resin is preferably 150°C or higher.

[0083] Examples of heat-resistant resins include polyarylene sulfides, polyethersulfones, polyamide-imides, polyimides, polyetherimides, polyether ether ketones, and aromatic polyesters.

[0084] The aforementioned polyarylene sulfide [PAS] is a resin containing a polymer having repeating units represented by the following general formula. There is no particular limitation on the aforementioned PAS; for example, polyphenylene sulfide [PPS] can be cited.

[0085] [Chemistry 3]

[0086]

[0087] (In the formula, Ar represents aryl.)

[0088] The polyethersulfone [PES] described above is a resin containing a polymer having repeating units represented by the following general formula.

[0089] [Chemistry 4]

[0090]

[0091] The PES mentioned above is not particularly limited, and examples include resins containing polymers obtained by polycondensation of dichlorodiphenyl sulfone and bisphenol.

[0092] The aforementioned polyamide-imide [PAI] is a resin containing polymers having amide and imide bonds in their molecular structure. There are no particular limitations on the PAI; examples include resins containing high molecular weight polymers obtained through reactions such as: the reaction of an aromatic diamine having an amide bond within the molecule with an aromatic tetracarboxylic acid such as pyromellitic acid; the reaction of an aromatic tricarboxylic acid such as trimellitic anhydride with a diamine such as 4,4-diaminophenyl ether or a diisocyanate such as diphenylmethane diisocyanate; the reaction of a diacid having an aromatic imide ring within the molecule with a diamine; and so on. From the perspective of excellent heat resistance, a polymer containing an aromatic ring in the main chain is preferred as the aforementioned PAI.

[0093] The aforementioned polyimide [PI] is a resin containing a polymer having an imide bond in its molecular structure. There are no particular limitations on the PI; examples include resins containing high molecular weight polymers obtained through reactions of aromatic tetracarboxylic anhydrides such as pyromellitic dianhydride. From the perspective of excellent heat resistance, a polymer containing an aromatic ring in its main chain is preferred as the aforementioned PI.

[0094] Because it can form a coating film with excellent adhesion to the substrate and excellent non-stick properties, the heat-resistant resin is preferably PAS or PES, and more preferably PAS.

[0095] PAS and PES can each contain one or more types.

[0096] The aforementioned heat-resistant resin is preferably PAS or PES, or PAI. That is, the aforementioned heat-resistant resin can be a mixture of PAS and PAI, or a mixture of PES and PAI. If the aforementioned heat-resistant resin contains PAI in addition to PAS or PES, a coating film with excellent secondary adhesion (adhesion to the substrate after repeated heating and cooling of the coating film) can be obtained. The aforementioned heat-resistant resin is more preferably a mixture of PAS and PAI, i.e., a mixture of PAS and PAI.

[0097] PAS, PES, and PAI can each contain one or more types.

[0098] When the heat-resistant resin is PAS or PES and PAI, the PAS or PES is preferably 80% to 99% by mass of the total amount of the PAS or PES and PAI. More preferably, it is 90% to 95% by mass.

[0099] In the above composition, the mass ratio of the fluororesin to the heat-resistant resin (fluororesin / heat-resistant resin) is preferably 1 / 99 to 40 / 60, more preferably 5 / 95 to 30 / 70, and even more preferably 10 / 90 to 25 / 75. If the mass ratio of the fluororesin to the heat-resistant resin is within the above range, a coating film with superior non-stick properties can be formed. The reason for this is that if a coating film is formed from a composition containing a relatively large amount of the heat-resistant resins such as polyarylene sulfone and polyethersulfone, water generated from cooking ingredients is less likely to penetrate the coating film, forming a thin film of water on the surface of the coating film. Due to this thin film of water, cooking ingredients are less likely to adhere to the coating film.

[0100] In the above composition, relative to the total amount of the fluororesin, heat-resistant resin, water, and solvent constituting the composition, the total amount of the fluororesin and the heat-resistant resin is preferably 20% to 50% by mass, more preferably 25% by mass or more, even more preferably 30% by mass or more, more preferably 45% by mass or less, and even more preferably 40% by mass or less. If the total amount of the fluororesin and the heat-resistant resin is within the above range, a coating film with better adhesion to the substrate and better non-stick properties can be formed.

[0101] The composition of the present invention is further characterized in that it contains water. By including water in the composition, the viscosity and tackiness of the composition can be increased. As a result, coatability and film thickness control are improved, and coating properties (e.g., corrosion resistance) can be enhanced.

[0102] For the above composition, since it can form a coating film that is easier to handle and has better physical properties, the concentration of solid components is preferably 5% to 70% by mass, more preferably 10% by mass or more, and more preferably 60% by mass or less.

[0103] The composition of the present invention preferably further comprises a filler material. By including a filler material, it is possible to form a coating film with better adhesion to the substrate, better non-stick properties, better hardness at high temperatures, and better wear resistance.

[0104] The Mohs hardness of the aforementioned filler material is preferably 7 or higher. By including a filler material with a specific hardness, it is possible to form a coating film with better adhesion to the substrate, better non-stick properties, better hardness at high temperatures, and better wear resistance.

[0105] The aforementioned filler material is preferably at least one selected from the group consisting of diamond, diamond fluoride, corundum, silica, boron nitride, boron carbide, silicon carbide, silicon dioxide, mica, chrysoberyl, topaz, beryl, garnet, quartz, glass flakes, fused zirconium oxide, tantalum carbide, titanium carbide, alumina, and tungsten carbide, more preferably at least one selected from the group consisting of diamond, boron carbide, silicon carbide, alumina, and fused zirconium oxide, and even more preferably diamond and silicon carbide.

[0106] Fluorinated diamond can be obtained by fluorinating diamond. The fluorination of diamond can be carried out using known methods, such as those disclosed in the proceedings of the 26th Symposium on Fluorine Chemistry, published on November 14, 2002 (Heisei 14), pp. 24-25. Specifically, fluorination is performed by sealing diamond in a reactor made of a material resistant to fluorine corrosion, such as nickel or nickel-containing alloys, and then introducing fluorine gas.

[0107] In the above composition, the content of the filler material is preferably 0.1% to 10% by mass, more preferably 0.3% by mass or more, and even more preferably 5.0% by mass or less, relative to the total amount of the fluororesin and the heat-resistant resin. If the content of the filler material is within the above range, a coating film with better adhesion to the substrate, better non-stick properties, better hardness at high temperatures, and better wear resistance can be formed.

[0108] The above composition preferably also contains a surfactant. Existing and known surfactants can be used as the surfactant.

[0109] The above composition may further include additives. There are no particular limitations on the additives mentioned above; examples include leveling agents, solid lubricants, anti-settling agents, moisture absorbers, surface conditioners, thixotropic agents, viscosity modifiers, anti-gelling agents, UV absorbers, light stabilizers, plasticizers, anti-blooming agents, anti-skinning agents, anti-scratch agents, antifungal agents, antibacterial agents, antioxidants, antistatic agents, silane coupling agents, carbon black, clay, extender pigments, flake pigments, barium sulfate, glass, various reinforcing materials, various additives, conductive fillers, and metal powders such as gold, silver, copper, platinum, and stainless steel.

[0110] The content of the above-mentioned additives relative to the total amount of the above-mentioned fluororesin and the above-mentioned heat-resistant resin is preferably 0.1% to 30% by mass, more preferably 1% or more by mass, and even more preferably 25% or less by mass.

[0111] The above composition can be prepared by mixing the above fluororesin, the above heat-resistant resin, the above water and the above solvent, the above filler material if necessary, the above surfactant and the above additives by a conventional mixing method in a mixer or roller mill.

[0112] The above composition is preferably a coating. The above composition may also be a water-based coating.

[0113] By applying the above composition to a substrate, a coating film can be formed. The formed coating film exhibits excellent adhesion to the substrate and excellent non-stick properties.

[0114] The above composition can be repeatedly coated, but a coating film with the desired properties can be formed with a single coating. The above composition can be suitably used as a coating for a single layer. Furthermore, the above composition can also form a thicker coating film with a single coating.

[0115] The coating method for the above composition is not particularly limited, and examples include spray coating, roller coating, coating using a doctor blade, dip coating, impregnation coating, swirl coating, curtain coating, etc., with spray coating being preferred.

[0116] After applying the above composition, the coating film can be dried or fired. Drying is preferably performed at a temperature of 70°C to 300°C for 5 to 60 minutes. Firing is preferably performed at a temperature of 260°C to 410°C for 10 to 30 minutes.

[0117] The present invention also relates to a coating film formed from the above composition (hereinafter also referred to as the first coating film). Because the first coating film of the present invention is formed from the above composition, it exhibits excellent adhesion to the substrate and excellent non-stick properties.

[0118] The present invention also relates to a coating (hereinafter also referred to as a second coating), characterized in that it is formed from a composition comprising water, including a fluoropolymer and a heat-resistant resin, and has an adhesion to rice cake of 20.0 g / cm² as determined by a rice cake adhesion test. 2 As described above, the second coating of the present invention exhibits excellent adhesion to the substrate and excellent non-stick properties.

[0119] The second coating described above is characterized in that its adhesion to rice cake, as determined by the rice cake adhesion test, is 20.0 g / cm. 2 Below. If the adhesion is within the above range, substances with high adhesiveness, such as amylose or amylopectin, contained in cooking ingredients will have difficulty adhering. The preferred adhesion is 18.0 g / cm³. 2 The preferred value is 15.0 g / cm³. 2 The following is a further preferred value of 14.0 g / cm³. 2 The following is an explanation. Additionally, the aforementioned adhesion can be 0.1 g / cm. 2 above.

[0120] The above adhesion properties are values ​​obtained through the following rice cake adhesion test.

[0121] A coating film with an adhesion test thickness of 20 μm was formed on a pure aluminum plate with a thickness of 2.0 mm, and a coating plate (3 cm × 3 cm) was prepared. On the side of the coating plate opposite to the coating film, two copper plates (3 cm × 3 cm × 2.0 mm each) were fixed with heat-resistant tape with a temperature resistance of over 100°C. A handle was then made on the copper plates with a metal wire to obtain a sample. On a heating plate heated to 90°C, a roughened aluminum plate (3 cm × 5 cm), a square-cut rice cake (sugary sliced ​​rice cake manufactured by Sato Foods Co., Ltd.), and the above sample were stacked in sequence. At this time, the above samples were stacked such that the coating film directly contacted the square-cut rice cake. After heating at 90°C for 2 minutes and 30 seconds, a spring scale was hung on the handle, and the sample was stretched vertically. The weight (g) at the moment when the coating film left the square-cut rice cake was recorded. Subtract the sample weight (including copper plate, tape, and metal wire) from the obtained weight and divide by the area of ​​the coated plate (9cm²). 2 This yielded the adhesion of the coating to the rice cake (g / cm). 2 ).

[0122] It should be noted that the weight of the tape and wire used is negligible compared to the weight of the sample.

[0123] Figure 1 This is a schematic diagram illustrating the method for the above-mentioned rice cake adhesion test. (See diagram for example.) Figure 1 As shown, an aluminum plate 6 is placed on a heating plate 8, a square-cut rice cake 7 is placed on the aluminum plate 6, and a sample 5 is placed on the square-cut rice cake 7. The sample 5 includes: a coating plate 1 having a coating film 1a and an aluminum plate 1b; two copper plates 2 and 3 fixed to the surface of the coating plate 1 opposite to the coating film 1a; and a handle 4 provided on the copper plate 3. The sample 5 is arranged such that the coating film 1a directly contacts the square-cut rice cake 7.

[0124] The second coating described above is further characterized in that it comprises a fluoropolymer and a heat-resistant resin. The preferred embodiments of the fluoropolymer and the heat-resistant resin are as described above.

[0125] In the second coating described above, the total amount of the fluororesin and the heat-resistant resin is preferably 80% to 99% by mass, more preferably 85% to 95% by mass, relative to the coating.

[0126] The second coating described above is further characterized in that it is formed from a composition containing water. By including water in the composition, the viscosity and tackiness of the composition can be increased. As a result, coatability and film thickness control are improved, and coating properties (e.g., corrosion resistance) can be enhanced. That is, compared with coatings formed from anhydrous compositions, the second coating described above exhibits superior coating properties.

[0127] The checkerboard test result for the second coating is preferably 100 / 100. Therefore, the second coating exhibits superior adhesion to the substrate.

[0128] The above checkerboard test can be performed by repeatedly peeling the celluloid tape 10 times according to JIS K5400.

[0129] The second coating mentioned above can be formed, for example, by applying the composition of the present invention to a substrate using the above method, drying it as needed, and then firing it.

[0130] The present invention also relates to a laminate comprising a substrate and the second coating film formed on the substrate. Even when the laminate consists of only the substrate and the coating film, the two layers are firmly bonded and exhibit excellent non-stick properties. Therefore, it can be suitably used as a cooking appliance such as a rice cooker.

[0131] The material used as the base material is not particularly limited, and examples include elemental metals such as iron, aluminum, and copper, and their alloys; and non-metallic inorganic materials such as enamel, glass, and ceramics. Stainless steel is an example of an alloy. Metals are preferred as the base material, aluminum or stainless steel are more preferred, and aluminum is even more preferred.

[0132] The aforementioned substrate may undergo surface treatments such as degreasing and roughening as needed. There are no particular limitations on the methods used for roughening; examples include chemical etching using acids or alkalis, anodizing (acid-resistant aluminum treatment), and sandblasting.

[0133] The film thickness of the above coating is preferably 1 μm to 50 μm, more preferably 5 μm or more, and even more preferably 40 μm or less. If the film thickness is too small, the corrosion resistance and wear resistance may deteriorate; if the film thickness is too large, cracks may easily form.

[0134] The coating can be formed as follows: the composition of the present invention is applied to the substrate by the above method, dried as needed, and then fired to form the coating.

[0135] The laminate may also include layers other than the substrate and the coating. However, in order to make full use of the high adhesion between the substrate and the coating, as well as the excellent properties of the coating, the laminate preferably has only the substrate and the coating.

[0136] The first coating, the second coating, and the laminate of the present invention described above can be used in applications utilizing the non-stick properties, heat resistance, and slip properties of fluoropolymers. For example, applications utilizing non-stick properties include: cooking appliances such as frying pans, pressure cookers, pots, striped griddles, rice cookers, ovens, heating plates, toasters, knives, and gas stoves; kitchen utensils such as electric kettles, ice makers, molds, and range hoods; food industry components such as mixing rollers, calendering rollers, conveyors, and feed hoppers; and rollers and belts for office automation (OA) systems. Industrial products such as OA separating claws, papermaking rollers, and calendering rollers for film manufacturing; molds for foamed styrene molding, casting molds, and mold release plates for plywood / decorative panel manufacturing; industrial containers (especially for the semiconductor industry); and applications utilizing sliding properties include: tools such as saws and files; household items such as irons, scissors, and kitchen knives; metal foil and wires; sliding bearings for food processing machines, packaging machines, and textile machinery; sliding parts for cameras / watches; automotive parts such as tube blanks, valves, and bearings; and snowplows, hoes, and parachutes.

[0137] Among them, it can be appropriately used in cooking utensils or kitchenware, especially in the inner pot of rice cookers.

[0138] The present invention also relates to a cooking appliance having the first coating of the present invention described above. Additionally, the present invention relates to a rice cooker having an inner pot having the first coating of the present invention described above. Furthermore, a cooking appliance having the second coating of the present invention, a rice cooker having an inner pot having the second coating of the present invention described above, a cooking appliance having the laminate of the present invention described above, and a rice cooker having an inner pot having the laminate of the present invention described above are also preferred embodiments of the present invention.

[0139] Example

[0140] Next, embodiments will be given to illustrate the present invention, but the present invention is not limited to the embodiments described herein.

[0141] The values ​​in the examples were measured using the following methods.

[0142] Fabrication of coated plates

[0143] The surface of a 2.0 mm thick pure aluminum plate (A-1050P) was degreased with acetone and then sandblasted to achieve a surface roughness Ra value of 2.0 μm to 3.0 μm as determined according to JISB 1982. After removing surface dust with a blower, the compositions obtained in the examples and comparative examples were spray-coated using a gravity spray gun with a nozzle diameter of 1.0 mm at a spray pressure of 0.2 MPa. The coating on the aluminum plate was dried at 80°C to 100°C for 15 minutes. Then, it was fired at 380°C for 20 minutes to produce a coated plate with a coating thickness of approximately 20 μm.

[0144] Rice cake adhesion test (non-stickiness)

[0145] A coating film with an adhesion test thickness of 20 μm was formed on a pure aluminum plate with a thickness of 2.0 mm, and a coating plate (3 cm × 3 cm) was prepared. On the side of the coating plate opposite to the coating film, two copper plates (3 cm × 3 cm × 2.0 mm each) were fixed with heat-resistant tape with a temperature resistance of over 100°C. A handle was then made on the copper plates with a metal wire to obtain a sample. On a heating plate heated to 90°C, a roughened aluminum plate (3 cm × 5 cm), a square-cut rice cake (sugary sliced ​​rice cake manufactured by Sato Foods Co., Ltd.), and the above sample were stacked in sequence. At this time, the above samples were stacked such that the coating film directly contacted the square-cut rice cake. After heating at 90°C for 2 minutes and 30 seconds, a spring scale was hung on the handle, and the sample was stretched vertically. The weight (g) at the moment when the coating film left the square-cut rice cake was recorded. Subtract the sample weight (including copper plate, tape, and metal wire) from the obtained weight and divide by the area of ​​the coated plate (9cm²). 2 This yielded the adhesion of the coating to the rice cake (g / cm). 2 ).

[0146] Checkerboard test (fitness)

[0147] According to JIS K5400 (repeatedly peel off the celluloid tape 10 times).

[0148] Examples and Comparative Examples

[0149] Example 1

[0150] Component 1: 60% aqueous dispersion of FEP

[0151] The second component is a 40% aqueous dispersion of PPS (an aqueous dispersion obtained by mixing and pulverizing 40 parts by weight of PPS powder, 20 parts by weight of TEG, 33 parts by weight of ion-exchanged water, 6 parts by weight of polyoxyethylene alkyl ether, and 1 part by weight of acetylene glycol in a sand mill).

[0152] The above components were mixed according to the mixing ratios described in Table 1, and stirred in a mixer for approximately 30 minutes to prepare the composition. Coated plates were then prepared using the above method, and the non-stick properties and adhesion of the coating were evaluated. The results are shown in Table 1.

[0153] Example 2

[0154] PES powder was used instead of PPS powder, and the same procedure as in Example 1 was repeated. The results are shown in Table 1.

[0155] Example 3

[0156] Instead of FEP aqueous dispersion, PFA aqueous dispersion was used, and the same procedure as in Example 1 was repeated. The results are shown in Table 1.

[0157] Example 4

[0158] BDG was used instead of TEG, and the same procedure as in Example 1 was repeated. The results are shown in Table 1.

[0159] Example 5

[0160] BTG was used instead of TEG, and the same procedure as in Example 1 was repeated. The results are shown in Table 1.

[0161] Example 6

[0162] The mixing ratio of fluoropolymer and binder was changed, but the same process as in Example 1 was repeated. The results are shown in Table 1.

[0163] Example 7

[0164] Component 1: 60% aqueous dispersion of FEP

[0165] The second component is a 40% aqueous dispersion of PPS (an aqueous dispersion obtained by mixing and pulverizing 40 parts by weight of PPS powder, 20 parts by weight of TEG, 33 parts by weight of ion-exchanged water, 6 parts by weight of polyoxyethylene alkyl ether, and 1 part by weight of acetylene glycol in a sand mill).

[0166] Component 3: 20% aqueous dispersion of carbon black

[0167] Component 4: 20% aqueous dispersion of barium sulfate

[0168] The above components were mixed according to the mixing ratios described in Table 1, and stirred in a mixer for approximately 30 minutes to prepare the composition. The subsequent processing method was the same as in Example 1. The results are shown in Table 1.

[0169] Example 8

[0170] Instead of TEG, a TEG / PG mixed solvent of 1 / 1 (mass ratio) was used, and the same procedure as in Example 7 was repeated. The results are shown in Table 1.

[0171] Comparative Example 1

[0172] Ion-exchanged water was used instead of TEG, and the same procedure as in Example 1 was repeated. The results are shown in Table 1.

[0173] Comparative Example 2

[0174] Instead of TEG, MMB was used, and the same procedure as in Example 1 was repeated. The results are shown in Table 1.

[0175] Comparative Example 3

[0176] Instead of TEG, NMP was used, and the same procedure as in Example 1 was repeated. The results are shown in Table 1.

[0177] [Table 1]

[0178]

[0179] The proportions in the table represent mass ratios.

[0180] The solvent amount in the table refers to the solvent amount (mass %) relative to the total amount of fluoropolymer, binder (heat-resistant resin), water and solvent.

[0181] The values ​​for additives in the table refer to the amount (mass %) of additives relative to the total amount of fluoropolymer and binder (heat-resistant resin).

[0182] In addition, the embodiments, comparative examples and abbreviations in the table are described below.

[0183] FEP: Tetrafluoroethylene / Hexafluoropropylene copolymer

[0184] PFA: Tetrafluoroethylene / Perfluoro(alkyl vinyl ether) copolymer

[0185] PPS: Polyphenylene sulfide

[0186] PES: Polyethersulfone

[0187] TEG: Triethylene Glycol

[0188] BDG: Diethylene glycol monobutyl ether

[0189] BTG: Triethylene Glycol Monobutyl Ether

[0190] PG: Propylene Glycol

[0191] MMB: 3-Methyl-3-methoxybutanol

[0192] NMP: N-methyl-2-pyrrolidone

[0193] Symbol Explanation

[0194] 1: Coated board

[0195] 1a: Coating

[0196] 1b: Aluminum plate

[0197] 2: Copper coin

[0198] 3: Copper coin

[0199] 4: Handle

[0200] 5: Sample

[0201] 6: Aluminum plate

[0202] 7: Cut the rice cake into squares

[0203] 8: Heating plate

Claims

1. A composition, characterized in that, It contains fluoropolymers, heat-resistant resins, water, and solvents with a boiling point above 235°C. The mass ratio of the fluoropolymer to the heat-resistant resin is 1 / 99 to 40 / 60. The total amount of the fluoropolymer and the heat-resistant resin is 20% to 50% by mass relative to the total amount of the fluoropolymer, the heat-resistant resin, the water, and the solvent. The fluororesin is a tetrafluoroethylene / hexafluoropropylene copolymer. The heat-resistant resin is polyarylene sulfide or polyethersulfone. The content of the solvent is 5% to 50% by mass relative to the total amount of the fluororesin, the heat-resistant resin, the water, and the solvent.

2. The composition of claim 1, wherein, The solvent has a boiling point of 265℃~300℃.

3. The composition according to claim 1 or 2, wherein, The solvent is at least one selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol, tripropylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, tetraethylene glycol dimethyl ether, and polyethylene glycol dimethyl ether.

4. The composition according to claim 1 or 2, wherein, The composition is a coating.

5. The composition according to claim 1 or 2, wherein, The composition is a coating for a single coating layer.

6. A coating film formed from the composition of claim 1, 2, 3, 4 or 5.

7. The coating as described in claim 6, wherein, The coating's adhesion to rice cake, as determined by a rice cake adhesion test, is 15.0 g / cm². 2 the following.

8. The coating as described in claim 6 or 7, wherein, The result of the checkerboard experiment was 100 / 100.

9. The coating as described in claim 7, wherein, The adhesion of the rice cake, as determined by the rice cake adhesion test, is 0.1 g / cm. 2 above.

10. A cooking appliance having the coating of claim 6.

11. A rice cooker having an inner pot having the coating of claim 6.

12. A laminate comprising a substrate and a coating of claim 7 or 8 formed on said substrate.

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