Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
  • B32B15/09—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyesters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D7/00—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D161/00—Coating compositions based on condensation polymers of aldehydes or ketones; Coating compositions based on derivatives of such polymers
  • C09D161/04—Condensation polymers of aldehydes or ketones with phenols only
  • C09D161/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/20—Diluents or solvents

Definitions

• the present invention relates to coating compositions.
• compositions such as epoxy, polyvinyl chloride, and polyester have been used as coatings for the inner surface of cans from the viewpoint of coating film performance such as corrosion resistance and coating workability.
• coating compositions containing epoxy resins produced using raw materials containing bisphenol A and the like as base resins have been widely and commonly used.
• a coating composition for the inner surface of a can that does not use raw materials containing bisphenol A (BPA) (including raw materials that may contain residual levels of BPA) is desired.
• BPA bisphenol A
• Patent Document 2 discloses a paint containing a polyester resin and a phenolic resin
• Patent Document 3 discloses two types having specific glass transition temperatures.
• a coating is disclosed containing a mixture of polyester resins of No. 1, pp.
• the coating films obtained from these paints are excellent in the coating film performance required for the inner surface of cans, such as workability, but when applied to the inner surface of can lids, the appearance of the coating film is not sufficient depending on the coating curing conditions. In addition, there is also a problem that workability may deteriorate due to deterioration over time.
• the problem to be solved by the present invention is to provide a paint that is excellent in scratch resistance, workability, and coating film appearance without using raw materials containing legally controlled substances such as bisphenol A, and is particularly suitable for the inner surface of can lids. It is to provide a composition.
• the present inventors have made intensive studies to solve the above problems, and as a result, a coating composition containing a polyester resin having a glass transition temperature within a specific range, a resol-type phenol resin, a curing catalyst, and an organic solvent component that satisfies specific requirements. According to the inventors, the inventors have found that the above problems can be solved, and have completed the present invention.
• the present invention provides a polyester resin (A) having a glass transition temperature of 30° C. to 80° C., a resol-type phenolic resin (B), an acid catalyst (C), and a hydrocarbon solvent (D1) having a boiling point of 130° C. or higher. , a ketone solvent (D2) with a boiling point of 110 ° C. or higher, and an organic solvent component (D) containing an alcohol solvent (D3) with a boiling point of 75 ° C.
• polyester resin (A) 1 to 30% by mass of the resole phenolic resin (B), an acid catalyst (C ) in an amount of 0.1 to 5.0% by mass and an organic solvent component (D) in an amount of 100 to 600% by mass.
• the present invention also provides a coated metal sheet having a cured coating film of the above coating composition.
• the present invention provides a coated metal can having a cured coating film of the above coating composition on at least a part of the can surface.
• the coating composition of the present invention without using raw materials containing legally controlled substances such as bisphenol A, it is excellent in scratch resistance, workability, and coating film appearance, and is particularly suitable for the inner surface of can lids.
• a composition can be provided.
• the present invention includes a polyester resin (A) having a glass transition temperature of 30 ° C. to 80 ° C., a resol type phenol resin (B), an acid catalyst (C), and a hydrocarbon solvent (D1) having a boiling point of 130 ° C. or higher, a boiling point Characterized by containing an organic solvent (D) containing, as essential components, a ketone solvent (D2) with a boiling point of 110°C or higher and an alcohol solvent (D3) with a boiling point of 75°C or higher, satisfying predetermined quantitative requirements. It relates to a paint composition (hereinafter sometimes referred to as the present paint for short).
• polyester resin (A) is a polyester resin containing hydroxyl groups, and includes oil-free polyester resins, alkyd resins, and modified products of these resins, such as urethane-modified polyester resins and urethane-modified alkyd resins. and so on.
• an oil-free polyester resin can be preferably used.
• An oil-free polyester resin refers to a polyester resin that does not contain fatty acids.
• the above oil-free polyester resin is mainly an esterified product of polybasic acid and polyhydric alcohol.
• the polybasic acid is selected from, for example, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, hexahydroterephthalic acid, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride, and the like.
• phthalic anhydride isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, hexahydroterephthalic acid, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride, and the like.
• dibasic acid or in addition to dibasic acid trivalent or higher polybasic acid such as trimellitic anhydride, methylcyclohexene tricarboxylic acid, pyromellitic anhydride can be used.
• monobasic acids such as benzoic acid, crotonic acid, and pt-butylbenzoic acid can be used together with polybasic acids.
• polyhydric alcohols examples include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, Dihydric alcohols such as 1,6-hexanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,4-dimethylol-cyclohexane are mainly used, Instead of dihydric alcohol or in addition to dihydric alcohol, trihydric or higher polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane and pentaerythritol can also be used. These polyhydric alcohols can be used alone or in combination of two or more. The esterification reaction of both the polybasic acid and polyhydric alcohol components can
• the oil-free polyester resin can also be obtained by transesterification using a lower alkyl ester (e.g., methyl ester, ethyl ester, etc.) of a polybasic acid instead of the polybasic acid in the esterification reaction.
• a lower alkyl ester e.g., methyl ester, ethyl ester, etc.
• the transesterification reaction of both the lower alkyl ester of polybasic acid and the polyhydric alcohol can be carried out by a known method.
• the aromatic dicarboxylic acid accounts for 80 to 100 mol% of the dibasic acid, and that the terephthalic acid accounts for 40 to 100 mol%.
• the alkyd resin is a resin obtained by reacting an oil fatty acid by a known method in addition to the acid component and the alcohol component of the oil-free polyester resin. Flaxseed oil fatty acid, safflower oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, tung oil fatty acid and the like can be mentioned.
• the urethane-modified polyester resin is the oil-free polyester resin or a low-molecular-weight oil-free polyester resin obtained by reacting an acid component and an alcohol component in the production of the oil-free polyester resin, and is known as a polyisocyanate compound. It is a resin obtained by reacting with a method.
• the urethane-modified alkyd resin is a resin obtained by reacting the above-mentioned alkyd resin or a low-molecular-weight alkyd resin obtained by reacting each component in the production of the above-mentioned alkyd resin with a polyisocyanate compound by a known method.
• Polyisocyanate compounds used for producing urethane-modified polyester resins and urethane-modified alkyd resins include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′- methylenebis(cyclohexylisocyanate), 2,4,6-triisocyanatotoluene, and the like.
• the polyester resin (A) preferably has a glass transition temperature (hereinafter sometimes abbreviated as "Tg point") of 30 to 80°C, particularly preferably in the range of 40 to 65°C. If the Tg point is less than 30°C, it is not preferable in terms of scratch resistance. If the Tg point exceeds 80°C, it is not preferable in terms of workability.
• Tg point glass transition temperature
• the number average molecule of the polyester resin (A) is preferably within the range of 3,000 to 100,000, more preferably within the range of 8,000 to 50,000, and more preferably within the range of 10,000 to 30 ,000 is more preferred.
• the hydroxyl value of the polyester resin (A) is preferably 0.5-40 mgKOH/g, more preferably 3-20 mgKOH/g.
• the acid value of the polyester resin (A) is preferably 20 mgKOH/g or less, more preferably 10 mgKOH/g or less, even more preferably 2 mgKOH/g or less. These ranges are suitable from the viewpoints of ease of handling of the polyester resin, workability of the resulting coating film, hardness, and the like.
• the polyester resin (A) can be used alone or in combination of two or more.
• the Tg point is measured by differential thermal analysis (DSC) using a differential scanning calorimeter, and the number average molecular weight is measured by gel permeation chromatography (GPC) according to the following molecular weight measurement method. It is measured using a polystyrene calibration curve.
• DSC differential thermal analysis
• GPC gel permeation chromatography
• Resol type phenolic resin (B) The resol-type phenolic resin, which is the component (B) in this paint, is added as a cross-linking agent for curing by cross-linking reaction with the polyester resin (A).
• a resol-type phenol resin is a resin obtained by condensation reaction of a phenol component and a formaldehyde component in the presence of an alkali catalyst.
• phenol components include bifunctional phenols such as o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol and 2,5-xylenol; trifunctional phenols such as m-cresol, phenol, m-ethylphenol, 3,5-xylenol, m-methoxyphenol; Examples include tetrafunctional phenols such as bisphenol A and bisphenol F, and these can be used singly or in combination of two or more.
• bisphenol A is not preferable to use in this paint from the viewpoint of environmental regulations.
• Formaldehyde components include formaldehyde, paraformaldehyde, trioxane, and the like, and these can be used alone or in combination of two or more.
• the resol-type phenol resin (B) in the present invention contains 50 to 100% by mass of m-cresol and 0 to 50% by mass of p-cresol (more particularly, 50 to 90% by mass of m-cresol and 10 to 10% by mass of p-cresol). 50% by mass)) are heated in the presence of a reaction catalyst to cause a condensation reaction to introduce a methylol group to obtain a methylolated phenol resin, and the methylol group of the resulting methylolated phenol resin is obtained.
• a resol-type phenolic resin (B1) obtained by alkyl-etherifying a part of it with an alcohol can be preferably used.
• the resol-type phenolic resin (B1) has excellent reactivity, and the crosslinked coating film has excellent workability.
• the resol-type phenolic resin (B1) and the polyester resin (A) in predetermined amounts to form a coating composition, it is possible to obtain a coating film excellent in corrosion resistance, especially in highly processed areas.
• the phenolic component described above can be used in combination with m-cresol and p-cresol as the starting phenolic component.
• a phenol containing 70 to 90% by mass of a trifunctional or higher phenol containing m-cresol and 10 to 30% by mass of a bifunctional phenol containing p-cresol Particular preference is given to using ingredients.
• a monohydric alcohol having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms can be suitably used as the alcohol used to alkyl-etherify a portion of the methylol groups of the methylolated phenolic resin.
• Suitable monohydric alcohols include methanol, ethanol, n-propanol, n-butanol, isobutanol and the like.
• the average number of alkoxymethyl groups per benzene nucleus is based on the total number of alkoxymethyl groups and methylol groups in terms of reactivity with the polyester resin (A). Furthermore, it is preferable that each benzene nucleus has an average of 0.5 or more, more preferably 0.6 to 3.0, alkoxymethyl groups per nucleus.
• Acid catalyst (C) accelerates the curing reaction of the present paint, and specifically includes sulfonic acid compounds such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and dinonylnaphthalenedisulfonic acid.
• acid catalysts such as phosphoric acid, amine neutralized products of these acids, and the like.
• the above sulfonic acid compounds or amine-neutralized sulfonic acid compounds can be preferably used.
• the organic solvent component (D) includes, as essential components, a hydrocarbon solvent (D1) with a boiling point of 130°C or higher, a ketone solvent (D2) with a boiling point of 110°C or higher, and an alcoholic solvent (D3) with a boiling point of 75°C or higher. ).
• hydrocarbon solvent (D1) examples include xylene (boiling point 139° C.), Solvesso 100 (boiling point 150-185° C.), Solvesso 150 (boiling point 178-209° C.), ethylcyclohexane (boiling point 133° C.), and the like. can.
• Examples of the ketone solvent (D2) include methyl isobutyl ketone (boiling point 116°C), cyclohexanone (boiling point 156°C), and isophorone (boiling point 215°C).
• Examples of the alcohol solvent (D3) include ethanol (boiling point 78°C), n-propanol (boiling point 97°C), isopropanol (boiling point 82°C), n-butanol (boiling point 118°C), and sec-butanol (boiling point 100°C).
• tert-butanol (boiling point 83° C.), isobutanol (boiling point 108° C.), n-hexanol (boiling point 157° C.), octanol (boiling point 197° C.), 2-ethylhexanol (boiling point 185° C.), and the like.
• an organic solvent (D4) other than the components (D1), (D2), and (D3) can also be used.
• Ether-based solvents such as tetrahydrofuran, dioxane, dimethoxyethane
• Ether alcohol solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monopropyl ether;
• Oxohexyl acetate (commonly known as "OHA”, boiling point 170°C), 3-methoxybutyl acetate (commonly known as "MBA”, “methoace”, boiling point 172°C), methylmethoxybutyl acetate (commonly known as "Solfit acetate", boiling point 188°C)
• ethylene glycol monobutyl ether acetate commonly known as "butyl acetate", boiling point 19
• the organic solvent component (D4) can be used alone or in combination with (D1), (D2), and (D3).
• the coating composition contains the polyester resin (A), the resol-type phenolic resin (B), the acid catalyst (C) and the organic solvent component (D) in the following proportions.
• the blending ratio of the polyester resin (A) is 70 to 99% by mass, preferably 75 to 95% by mass, in particular, based on the total solid content of the polyester resin (A) and the resol-type phenolic resin (B). It is preferably 80 to 95% by mass.
• the blending ratio of the polyester resin (A) is less than 70% by mass, processability may deteriorate, and if it exceeds 99% by mass, water resistance may deteriorate.
• the blending ratio of the resol-type phenolic resin (B) is 1 to 30% by mass, preferably 2 to 25% by mass, as a solid content with respect to the total solid content of the polyester resin (A) and the resol-type phenolic resin (B). , particularly preferably in the range of 2 to 20% by weight.
• the mixing ratio of the acid catalyst (C) is 0.1 to 5.0% by mass, preferably 0.2, as a solid content with respect to the total solid content of the polyester resin (A) and the resol-type phenolic resin (B). It is within the range of to 3.0% by mass. Being within the above range is preferable from the viewpoint of the curability and physical properties of the coating film to be obtained.
• the acid catalyst (C) when the acid catalyst (C) also contains a compound other than the acid (for example, an amine in the case of an amine neutralized product of a sulfonic acid compound), the portion of the compound other than the acid is excluded.
• a compound other than the acid for example, an amine in the case of an amine neutralized product of a sulfonic acid compound
• the blending ratio of the organic solvent component (D) is 100 to 600% by mass, preferably 100 to 400% by mass, particularly preferably 150%, based on the total solid content of the polyester resin (A) and the resol-type phenolic resin (B). It is within the range of ⁇ 300% by mass. Being within the above range is preferable from the viewpoint of coating film appearance, coating workability, and the like.
• the organic solvent component (D) Of the total amount of the organic solvent component (D), the sum of the hydrocarbon solvent (D1) having a boiling point of 130°C or higher, the ketone solvent (D2) having a boiling point of 110°C or higher, and the alcoholic solvent (D3) having a boiling point of 75°C or higher.
• the amount is preferably 50 mass % or more, more preferably 60 to 95 mass %, still more preferably 65 to 90 mass %.
• the above ratio is 50% by mass or more, it is preferable in terms of coating film appearance, coating workability, and coating storage stability.
• the amount of the hydrocarbon solvent (D1) having a boiling point of 130°C or higher is preferably 5-80% by mass, more preferably 15-50% by mass.
• the blending ratio of the hydrocarbon solvent (D1) is 5% or more, the coating workability is good, and when it is 80 mass or less, it is preferable in terms of the solubility of the polyester resin (A) and the storage stability of the paint. be.
• the amount of the ketone solvent (D2) having a boiling point of 110°C or higher is preferably 15-60% by mass, more preferably 25-55% by mass.
• the blending ratio of the ketone-based solvent (D2) is 15% or more, it is preferable in terms of the solubility of the polyester resin (A) and paint storability, and when it is 60% by mass or less, the coating workability is good.
• the amount of the alcohol solvent (D3) having a boiling point of 75°C or higher is preferably 1 to 20% by mass, more preferably 3 to 12% by mass. If the blending ratio of the alcoholic solvent (D3) is less than 1%, the solubility of the resol-type phenolic resin (B) may decrease, and if it exceeds 20% by mass, the solubility of the polyester resin (A) decreases. sometimes.
• the coating composition of the present invention further contains a lubricity imparting agent and a coating film modifier.
• Coating additives such as resins (amino resins, etc.), pigments, aggregation inhibitors, antifoaming agents, leveling agents, etc., can be appropriately blended.
• the lubricity-imparting agent is used for the purpose of improving the lubricity of the coating film to be obtained.
• Polyolefin wax such as polyethylene, lanolin wax, montan wax, microcrystalline wax, carnauba wax and the like can be mentioned. Lubricity imparting agents can be used alone or in combination of two or more.
• a lubricity-imparting agent By adding a lubricity-imparting agent to the coating composition of the present invention, it is possible to impart lubricity to the surface of the coating film obtained from the composition, reduce the frictional resistance of the coating surface, and improve moldability. Corrosion resistance after working is also improved.
• the amount of the lubricity imparting agent is based on the total solid content of the polyester resin (A) and the resol-type phenolic resin (B) from the viewpoint of moldability, corrosion resistance, etc. based on the flexibility and lubricity of the coating film. , preferably 0.1 to 20 mass %, more preferably 0.2 to 10 mass %, still more preferably 0.5 to 5 mass %.
• coating film-modifying resin examples include amino resins, ethylene-polymerizable unsaturated carboxylic acid copolymers, and ethylene-polymerizable carboxylic unsaturated acid copolymer ionomers.
• the above amino resin is blended for the purpose of improving the curability of the coating composition, improving the hardness of the resulting coating film, improving adhesion, and the like.
• Amino resins are condensation products of aldehydes such as formaldehyde, acetaldehyde, crotonaldehyde and benzaldehyde and substances containing amino or amide groups such as urea, melamine and benzoguanamine, and may be alkyl-etherified with alcohols.
• Alcohols can include monohydric alcohols such as methanol, ethanol, propanol, butanol, hexanol, benzyl alcohol, cyclohexanol and ethoxyethanol.
• amino resins include benzoguanamine-formaldehyde resin, melamine-formaldehyde resin, and urea-formaldehyde resin.
• the blending amount is preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, based on the total solid content of the polyester resin (A). Within range.
• the ethylene-polymerizable unsaturated carboxylic acid copolymer and the ethylene-polymerizable carboxylic unsaturated acid copolymer ionomer can be blended for the purpose of improving the flexibility of the coating film.
• a coloring pigment eg, titanium oxide
• an extender pigment e.g., an extender pigment, or the like known in the paint field
• the coating composition of the present invention can be applied to various substrates such as metal plates, metal cans, plastics, and glass plates.
• the painted metal sheet of the present invention can be obtained by applying the coating composition of the present invention to a metal sheet.
• the metal plate examples include hot-rolled steel plate, cold-rolled steel plate, hot-dip galvanized steel plate, electro-galvanized steel plate, alloy-plated steel plate, aluminum-zinc alloy-plated steel plate, aluminum plate, tin plate, tin-plated steel plate, stainless steel plate, copper plate, Examples include copper-plated steel sheets, tin-free steels, nickel-plated steel sheets, ultra-thin tin-plated steel sheets, chromium-treated steel sheets, etc., and if necessary, those subjected to various surface treatments and primer coating can also be used.
• any metal sheet that can be used for beverage cans, cans for canning, lids, caps, etc. can be used, for example, aluminum. Plates, tin-free steel plates, tinplates and the like can be mentioned.
• the coated metal sheet of the present invention is obtained by coating the coating composition of the present invention on a metal sheet by various known methods such as roll coater coating, spray coating, immersion coating, electrodeposition coating, etc., followed by heating means such as a continuous baking furnace. It can be obtained by baking by Among the above coating methods, roll coater coating or spray coating is preferred, and roll coater coating is particularly preferred.
• the baking conditions are not particularly limited, but for example, the maximum temperature reached by the material is 120° C. to 300° C., preferably 180° C. to 260° C., for 5 seconds to 30 minutes, preferably 10 seconds to 10 minutes. , more preferably 10 to 60 seconds.
• the coating amount of the coated metal sheet can be appropriately determined according to the use of the coated metal sheet, and the weight of the cured coating film is usually about 10 to 200 mg/100 cm 2 , preferably about 20 to 150 mg/100 cm 2 .
• the painted metal can of the present invention is formed by forming a coating film of the coating composition of the present invention on at least the inner surface and/or the outer surface of the can body or can lid of the metal can, and at least the inner surface of the metal can. It is preferable that a cured coating film is formed from the coating composition of the present invention.
• the coated metal can of the present invention can be formed by forming a metal can from the above-described coated metal sheet, but the coating composition of the present invention is applied to a preformed metal container and cured to form a cured coating film. can also be obtained by
• metal container for forming the cured coating film all conventionally known metal cans can be used, and although not particularly limited, three-piece cans and two-piece cans having side seams, such as can bodies, can be mentioned.
• the above can lid can be formed from the above-described coated metal sheet of the present invention by any conventionally known lid manufacturing method. Generally, it is molded as a stay-on-tab type easy-open can lid or a full-open type easy-open can lid.
• the form of the can to be coated with the coating composition of the present invention includes a two-piece can composed of two parts, a lid and a body integrated with the bottom, and a three-piece can composed of a lid, a bottom, and a body.
• Three-piece cans, bottle cans, etc. consisting of two portions can be mentioned, and the coating composition of the present invention can be applied to each of the above portions.
• the coating film obtained from the coating composition of the present invention does not contain legally regulated substances such as bisphenol A and is excellent in scratch resistance, workability, and coating film appearance. can be suitably used for Moreover, the coating film obtained from the coating composition of the present invention can be suitably used particularly for the inner surface of can lids.
• the present invention also includes the following configurations.
• Section 1 A polyester resin (A) having a glass transition temperature of 30° C. to 80° C., a resol type phenolic resin (B), an acid catalyst (C), a hydrocarbon solvent (D1) having a boiling point of 130° C. or higher, and a boiling point of 110° C. or higher
• Item 1 The coating composition according to Item 1, wherein the amount is 50% by mass or more.
• Item 3. The coating composition according to item 1 or 2, wherein the amount of the hydrocarbon solvent (D1) having a boiling point of 130° C. or higher is 5 to 80% by mass in the total amount of the organic solvent component (D). Section 4. Item 3.
• a coated metal plate having a cured coating film of the coating composition according to any one of Items 1 to 6.
• a coated metal can having a cured coating film of the coating composition according to any one of Items 1 to 6 on at least a part of the can surface.
• Item 9. A coated metal can having a cured coating film of the coating composition according to any one of Items 1 to 6 on the inner surface of the can lid.
• Parts by mass of raw materials in the following production examples, examples, and comparative examples represent parts by mass of the solid content (or active ingredient) of the raw materials (excluding the organic solvent component (D)).
• polyester resin (A) Production Example 1 Polyester resin "Vylon 103" manufactured by Toyobo Co., Ltd. (number average molecular weight: 22,000, hydroxyl value: 5 mgKOH/g, acid value: 2 mgKOH/g or less, Tg point: 45°C) was used as polyester resin (A-1).
• Production example 2 49.8 parts of terephthalic acid, 49.8 parts of isophthalic acid, 34.4 parts of hexahydroterephthalic acid, 28.3 parts of adipic acid, 99.8 parts of neopentyl glycol, 6.8 parts of trimethylolpropane and a polycondensation catalyst An esterification reaction is carried out while removing water generated by charging, heating and stirring, and a polyester resin (A -2) was obtained.
• Polyester resin "Unitika Eliether UE-9100" manufactured by Unitika Ltd. (number average molecular weight 30,000, hydroxyl value 2 mgKOH / g, acid value 2 mgKOH / g or less, Tg point 18 ° C.) as polyester resin (A-3) bottom.
• Polyester resin "Unitika Elitel UE-9900" manufactured by Unitika Ltd. (number average molecular weight 15,000, hydroxyl value 8 mgKOH/g, acid value 2 mgKOH/g, Tg point 101°C) was used as the polyester resin (A-4). .
• the polyester resin (A-3) of Production Example 3 and the polyester resin (A-4) of Production Example 4 are for comparative examples.
• Production Examples 6-7 In Production Example 5, the procedure was carried out in the same manner as in Production Example 5, except that 100 parts of the phenol component shown in Table 1 below was used instead of using 70 parts of m-cresol and 30 parts of p-cresol, and the solid content was about 50%. Each resol type phenolic resin solution (B-2) to (B-3) was obtained.
• each resol-type phenolic resin solution (B-1) to (B-3) is n-butanol.
• Example 1 To 80 parts of the polyester resin (A-1) obtained in Production Example 1, 40 parts of the resol-type phenolic resin (B-1) solution obtained in Production Example 5 (20 parts in terms of solid content) and "NAICURE 5225" (*1 ) 1.2 parts (0.3 parts as the amount of dodecylbenzenesulfonic acid) are mixed and dissolved, and then the total solid content (100 parts) of the polyester resin (A-1) and the resol-type phenolic resin (B-1) ), 10 parts of ethyl cyclohexane, 120 parts of methyl isobutyl ketone, 6 parts of ethanol, 6 parts of isopropyl alcohol, 20 parts of butanol and 38 parts of ethylene glycol monobutyl ether, solid content 31.2% paint composition No. got 1. (*1) Naicure 5225: USA, King Industries, trade name, amine-neutralized solution of dodecylbenzenesulfonic acid, content of dodecylbenzen
• Examples 2-40 and Comparative Examples 1-16 The same procedure as in Example 1 was repeated except that the compositions shown in Table 2 below were used. 2-56 were obtained. In addition, the compounding quantity of A component, B component, and C component in Table 2 is solid content amount. The amount of Naicure 5225 is the solid content of dodecylbenzenesulfonic acid.
• the total solvent amount in Table 2 is the amount relative to the total solid content of 100 parts of the A component and the B component.
• coating composition No. 41 to 56 are for comparative examples.
• (*2) in Table 2 are as follows.
• the amount of Naicure 2500 in Table 2 is the solid content of p-toluenesulfonic acid.
• test coated plate Each coating composition obtained in the above examples and comparative examples was roll-coated on a #5182 aluminum plate with a thickness of 0.27 mm so that the dry coating weight was 80 to 90 mg/100 cm 2 , Each test coated plate was obtained by passing through a conveyer-type hot-air drying oven and baking. The baking conditions were such that the maximum temperature reached by the material (PMT) was 255° C. and the passage time in the drying furnace was 20 seconds. Various tests were performed on the obtained test coated plate according to the following test methods. The test results are also shown in Table 2 below.
• Test method Coating film appearance The appearance of the test coated plate was observed with the naked eye. The case where no coating surface abnormality such as repelling, denting, cloudiness or turbidity was observed was rated as (S), and the case where the above-mentioned abnormality was slightly observed but could be judged to be of a practically acceptable level was rated as (A). When coating surface abnormalities such as cissing, dents, cloudiness, and turbidity occurred on the coating surface, it was rated as (B), and when significant coating surface abnormalities occurred, it was rated as (C).
• test coated plate After cutting the test coated plate 5 cm in the rolling direction and 4 cm in the direction perpendicular to the rolling direction, it was cut into 5 cm ⁇ 4 cm at a point closer to one of the short sides than the midline of the two short sides.
• the test coated plate was folded in two parallel to the short side.
• the test coated plate was arranged so that the side with the larger area when folded in two was on the top and the side with the smaller area was on the bottom.
• two aluminum plates with a thickness of 0.26 mm were sandwiched between the bent portions of the test piece of the painted plate for testing, and set in a special seam-fold type DuPont impact tester.
• An iron weight with a flat contact surface weighing 1 kg was dropped from a height of 50 cm to give an impact to the bent portion, and then the bent tip portion was energized with an applied voltage of 6.5 V for 6 seconds.
• a current value (mA) of a width of 20 mm at the tip of the bent portion was measured and evaluated according to the following criteria. If the workability of the coating film is poor, the coating film will crack at the bent portion, exposing the underlying metal plate and increasing the electrical conductivity, resulting in a higher current value.
• S is less than 10 mA A is 10 mA or more and less than 20 mA B is 20 mA or more and less than 40 mA C is 40 mA or more
• Scratch resistance Using a Bowden friction tester (manufactured by Shinko Engineering Co., Ltd., Soda type adhesion slip tester), a friction test was performed under the conditions of a 3/16 inch steel ball with a friction part diameter of 4 kg and a friction speed of 7 reciprocations/minute. , the number of times of rubbing until the coating film was scratched was measured. Evaluation was made according to the following criteria. S: no scratches even after 200 times of friction; A: Scratches occur after 150 to 200 friction cycles, B: Scratches occur when the number of frictions is less than 50 to 150 times, C: Scratches occur when the number of frictions is less than 10 to 50 times, D: Scratches occurred with less than 10 times of friction.

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