JP5674601B2 - Coating composition and coating film forming method - Google Patents

Description

By using it as a paint to form a top coat film, the present invention suppresses gloss, has an excellent metallic feeling, has a smooth feel when touched by hand, and is resistant to scratches and has chemical resistance. The present invention relates to a coating composition capable of forming an excellent coating film and a coating film forming method.

In industrial products such as automobiles, a silver metallic paint color whose brightness changes greatly from a highlight (near specular reflection light) to a shade (oblique direction) has become very popular. Among them, a paint color with suppressed gloss is attracting attention as a calm metallic paint color.

  As a method of forming a metallic coating color with suppressed gloss, a method of forming two layers of a metallic coating containing a scaly aluminum pigment and a clear coating containing a gloss adjusting agent on a substrate is common. . In this case, two coating steps are required, and there are problems such as an increase in cost and an increase in environmental load.

  As a coating composition capable of obtaining a matte coating film by a single coating, Patent Document 1 contains a specific hydroxyl group-containing resin, a curing agent, a resin-coated colored aluminum pigment, and an ultraviolet absorber. A one-coat matte metallic paint is described. By coating the resin, the brightness of the scaly aluminum pigment is reduced, but there is a problem that the gloss is not sufficiently suppressed.

JP 2004-339492 A

The purpose of the present invention is to suppress the gloss by using it as a paint for forming a top coat film, to have a metallic feeling, to have a smooth feeling when touched by hand, and to prevent chemical damage. It is providing the coating composition which can form the coating film excellent in the property, and the coating-film formation method.

The present invention
1. A coating composition comprising a scaly aluminum pigment, a talc pigment and a fiber-based resin;
2. 2. The coating composition according to item 1, wherein the average particle size of the scaly aluminum pigment is in the range of 5 to 40 μm,
3. The coating composition according to Item 1 or 2, wherein the scaly aluminum pigment is a resin-coated aluminum pigment having a resin composition coated on the surface thereof,
4). The coating composition according to any one of items 1 to 3, wherein the talc pigment is scaly and has an average particle size in the range of 3 to 15 µm,
5. Furthermore, the coating composition of any one of 1-4 containing the resin composition which can be bridge | crosslinked and hardened by the urethanation reaction containing a hydroxyl-containing resin and an isocyanate compound,
6). A method for forming a coating film, which comprises applying the coating composition described in items 1 to 5 to a substrate;
7). The coating film forming method according to item 6, wherein the base material is a color base coating film obtained by applying a color base coating.

According to the present invention, by using it as a paint for forming a topcoat coating film, the gloss is suppressed, the metal feeling is excellent, there is a smooth feeling when touched by hand, and the chemical resistance is hard to be scratched. The coating composition and coating-film formation method which can form the coating film excellent in the property can be obtained.

The coating composition of the present invention contains a scaly aluminum pigment for the purpose of increasing the brightness in the highlight of a coating film obtained by coating.

  The scaly aluminum pigment is generally produced by grinding and grinding aluminum in a ball mill or attritor mill using a grinding aid in the presence of a grinding fluid. As the grinding aid, aliphatic amines, aliphatic amides and aliphatic alcohols are used in addition to higher fatty acids such as oleic acid, stearic acid, isostearic acid, lauric acid, palmitic acid and myristic acid. Aliphatic hydrocarbons such as mineral spirits are used as the grinding fluid.

  The scaly aluminum pigment can be roughly classified into a leafing type and a non-leafing type depending on the type of grinding aid. The leafing type is an arrangement (leafing) on the surface of the coating film obtained by painting when blended into a paint composition, giving a strong finish with a metallic feel, heat reflection, and rust prevention Therefore, it is often used for various building materials such as tanks, ducts, piping and roof roofing. In the coating composition of the present invention, it is preferable to use a non-leafing type scaly aluminum pigment from the viewpoint of highlight brightness of a coating film obtained by coating and water resistance.

  The scale-like aluminum pigment preferably has an average particle size in the range of 5 to 40 μm from the viewpoint of the finish of the coated film and the brightness of the highlight, more preferably the particle size. The diameter is in the range of 7 to 25 μm, particularly preferably in the range of 8 to 23 μm. It is preferable to use a thickness in the range of 0.05 to 0.5 μm. The particle size and thickness here mean the median diameter of the volume-based particle size distribution measured by a laser diffraction scattering method using a Microtrac particle size distribution measuring device MT3300 (trade name, manufactured by Nikkiso Co., Ltd.).

  In addition, the content of the scaly aluminum pigment is within the range of 0.1 to 25 parts by mass in total with respect to 100 parts by mass of the resin solid content in the paint from the point of finish of the coating film obtained by coating. Is preferable, more preferably in the range of 0.3 to 20 parts by mass, and particularly preferably in the range of 0.5 to 20 parts by mass.

  The scaly aluminum pigment of the present invention is 0.01 to 10 parts by mass of radically polymerizable unsaturated carboxylic acid with respect to 100 parts by mass of the scaly aluminum pigment from the viewpoint of chemical resistance of the coating film obtained by coating. And / or highly tertiary formed from 0.01 to 30 parts by weight of a phosphoric acid mono- or diester having a radically polymerizable double bond and 2 to 50 parts by weight of a monomer having three or more radically polymerizable double bonds. It is possible to use a resin-coated aluminum pigment whose surface is coated tightly with the original resin.

  In the coating composition of the present invention, a colored aluminum pigment can be used as the scaly aluminum pigment. Examples of the colored aluminum pigment include those obtained by adsorbing a colored pigment on the surface of a scaly aluminum pigment and further coating with a resin. For example, a colored aluminum pigment described in JP-A-1-315470 can be used. Or, the surface of the scaly aluminum pigment may be chemically vapor-deposited with iron oxide or the like and further coated with a resin.

The coating composition of the present invention contains a talc pigment for the purpose of suppressing gloss and improving touch. Talc is an inorganic powder obtained by finely pulverizing ore called talc, and is compositionally hydrous magnesium silicate [Mg ₃ Si ₄ O ₁₀ (OH) ₂ ]. The talc pigment is a scaly pigment having an average particle diameter of 3 to 15 μm obtained by pulverizing and classifying the talc. The average particle diameter here means a median diameter of a volume-based particle size distribution measured by a laser diffraction scattering method using a Microtrac particle size distribution measuring device MT3300 (trade name, manufactured by Nikkiso Co., Ltd.). In the present invention, it is preferable to use a talc pigment having an average particle diameter in the range of 3 to 15 μm from the viewpoint of suppressing the gloss of the coating film obtained by coating and imparting a soft texture.

  In the coating composition of the present invention, a color pigment can be blended for the purpose of finely adjusting the hue and brightness of a coating film obtained by coating. The color pigment is not particularly limited, and specifically, for example, a transparent iron oxide pigment, a composite oxide pigment such as titanium yellow, an inorganic pigment such as a fine particle titanium oxide pigment; an azo pigment, Quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments Organic pigments such as dioxazine pigments, selenium pigments, and indigo pigments; carbon black pigments, and the like. These may be used alone or in combination of two or more.

  In the present invention, it is preferable to use a transparent pigment having a primary particle diameter of 200 nm or less when a coloring pigment is blended in terms of the metallic feeling of the coating film obtained by coating.

  The colored pigment can be blended in the paint as a powder, but a pigment dispersion is prepared in advance by mixing and dispersing the colored pigment with a part of the resin composition, and this is used as the remaining resin component and other components. It can also be made into a paint by mixing together. In preparing the pigment dispersion, conventional paint additives such as an antifoaming agent, a dispersing agent, and a surface conditioner can be used as necessary.

  When the color pigment is blended in the coating composition of the present invention, the blending amount is usually set to 0.1 to 100 parts by mass of the resin composition (solid content) from the viewpoint of a metallic feeling. It is preferable to be within a range of 01 to 30 parts by mass, particularly 0.05 to 25 parts by mass.

  The coating composition of the present invention contains a fiber-based resin from the viewpoint of controlling the viscosity of the coating in the coating film forming process and orienting the scaly aluminum pigment in parallel with the coating film in the coating film. The fiber-based resin is a resin containing a cellulose derivative such as cellulose ester, and those conventionally used for coatings can be used for the coating composition of the present invention.

  In the coating composition of this invention, you may contain resin other than the said fiber-type resin as a vehicle formation component. In that case, a resin usually used as a coating film-forming resin for paint can be used without limitation. For example, acrylic resin, polyester resin, alkyd resin, polyolefin resin, chlorinated polyolefin resin, fluorine resin, silicone resin, etc. can be used alone or in combination to form a non-crosslinked lacquer type, but amino resins, isocyanate compounds, epoxy compounds, etc. It can also be made into a cross-linking curable type in combination with the above cross-linking resin.

  In the coating composition of the present invention, when a resin other than a fiber-based resin is used, the amount is 5/95 to 50/50 as a mass ratio of the solid content of the fiber-based resin and the other resin. It is preferable to be within the range, more preferably 10/90 to 40/60. If the content of the fiber-based resin is too large, there may be a problem that the water resistance of the coating film obtained by coating is lowered, and if it is too small, the orientation of the scaly aluminum pigment may be lowered. is there.

  The coating composition of this invention can contain the resin composition which can be bridge | crosslinked and hardened | cured by the urethanation reaction which contains a hydroxyl-containing resin and the compound which has an isocyanate group as resin other than the said fiber-type resin.

  As said hydroxyl-containing resin, a hydroxyl-containing acrylic resin, a hydroxyl-containing polyester resin, etc. are mentioned, for example, These can be used individually or in combination of 2 or more types, respectively. These hydroxyl group-containing resins are usually used by being dissolved or dispersed in a solvent such as an organic solvent and / or water.

  The above hydroxyl group-containing acrylic resin has a hydroxyl group-containing polymerizable monomer as an essential component, and further contains a polymerizable monomer component containing a carboxyl group-containing polymerizable monomer and an acrylic monomer as required. Those produced by (co) polymerization by the method can be used. The hydroxyl group-containing acrylic resin is generally a number average molecular weight in the range of 1000 to 100000, particularly 5000 to 80000, generally 20 to 200 mg KOH / g, particularly 50 to 150 mg KOH / g, and generally 0 to 100 mg KOH / g. g, in particular those having an acid number in the range of 0 to 70 mg KOH / g are preferred.

  The hydroxyl group-containing polymerizable monomer is a compound having at least one hydroxyl group and polymerizable unsaturated bond in one molecule. For example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl ( Examples thereof include monoesterified products of a glycol having 2 to 20 carbon atoms such as (meth) acrylate and (meth) acrylic acid.

  The carboxyl group-containing polymerizable monomer is a compound having at least one carboxyl group and polymerizable unsaturated bond in one molecule, for example, acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, Examples thereof include mesaconic acid and the like, and anhydrides and half-esterified products of these acids.

  The acrylic monomer includes a monoesterified product of (meth) acrylic acid and a monohydric alcohol having 1 to 22 carbon atoms. Specifically, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl Examples include methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl methacrylate, lauryl acrylate, lauryl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate.

  In the present specification, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” means acrylic acid or methacrylic acid.

  In production of the hydroxyl group-containing acrylic resin, in addition to the hydroxyl group-containing polymerizable monomer, the carboxyl group-containing polymerizable monomer, and the acrylic monomer, other polymerizable monomers can be used in combination.

  Other polymerizable monomers include, for example, (meth) acrylic acid such as methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, etc., and alkoxy esters having 2 to 18 carbon atoms; N, N-dimethylamino Ethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, Nt-butylaminoethyl acrylate, Nt-butylaminoethyl methacrylate, N, N- Aminoacrylic monomers such as dimethylaminopropyl acrylate and N, N-dimethylaminopropyl methacrylate; acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide , Acrylamide monomers such as N-ethylacrylamide, N-ethylmethacrylamide, N-butylacrylamide, N-butylmethacrylamide, N-dimethylacrylamide, N-dimethylmethacrylamide; glycidyl groups such as glycidyl acrylate and glycidyl methacrylate Containing monomers: styrene, α-methylstyrene, vinyl toluene, acrylonitrile, vinyl acetate, vinyl chloride and the like.

  As said hydroxyl-containing polyester resin, what is normally manufactured by esterifying a polybasic acid and a polyhydric alcohol can be used.

  The polybasic acid is a compound having two or more carboxyl groups in one molecule. For example, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic acid, hexa Hydrophthalic acid, hetic acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, pyromellitic acid and their anhydrides can be mentioned. The polyhydric alcohol is two or more in one molecule. For example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, hydrogenated bisphenol A, triethylene glycol, glycerin, trimethylolethane, tri Ji trimethylolpropane, and pentaerythritol and the like.

  In addition, as the polyester resin, (semi) drying oil such as oil fatty acid, coconut oil fatty acid, safflower oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, eno oil fatty acid, hemp oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, etc. A fatty acid-modified polyester resin modified with a fatty acid or the like can also be used. The amount of modification with these fatty acids is preferably 30% by mass or less in terms of oil length. Further, it may be a partially reacted monobasic acid such as benzoic acid.

  Polyester resins generally have a number average molecular weight in the range of 1000 to 50000, especially 2000 to 20000, generally 20 to 200 mg KOH / g, in particular 50 to 150 mg KOH / g, and generally 0 to 100 mg KOH / g, Particularly preferred are those having an acid value within the range of 0 to 70 mg KOH / g.

  The isocyanate compound includes a polyisocyanate compound having at least two free isocyanate groups in one molecule. Examples of the polyisocyanate compound include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and lysine. Aliphatic polyisocyanates such as diisocyanates, burette type adducts and isocyanurate cycloadducts of these polyisocyanates; isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- (or − 2,6-) diisocyanate, 1,3- (or 1,4-) di (isocyanatomethyl) cyclohexane, 1,4-cyclohexane diisocyanate, Alicyclic diisocyanates such as 1,3-cyclopentane diisocyanate, 1,2-cyclohexane diisocyanate, burette type adducts and isocyanurate cycloadducts of these polyisocyanates; xylylene diisocyanate, tetramethyl xylylene diene Isocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4′-toluidine diisocyanate, 4,4′-diphenyl ether diisocyanate, (M- or p-) phenylene diisocyanate, 4,4′-biphenylene diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, bis (4-isocyanatof Nyl) sulfone, aromatic diisocyanate compounds such as isopropylidenebis (4-phenylisocyanate), burette type adducts and isocyanurate cycloadducts of these polyisocyanates; hydrogenated MDI and hydrogenated MDI derivatives; triphenylmethane -4,4 ', 4 "-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4'-dimethyldiphenylmethane-2,2', 5 Polyisocyanates having at least three isocyanate groups in one molecule such as 5′-tetraisocyanate, burette-type adducts and isocyanurate cycloadducts of these polyisocyanates; ethylene glycol, propylene glycol, 1,4- Butylene glycol, dimethylol Urethane adducts obtained by reacting a polyisocyanate compound in an excess ratio of isocyanate groups to the hydroxyl groups of polyols such as propionic acid, polyalkylene glycol, trimethylolpropane and hexanetriol, and burette type addition of these polyisocyanates Products and socyanurate cycloadducts.

  The mixing ratio of the hydroxyl group-containing resin and the isocyanate compound in the coating composition of the present invention is such that the isocyanate group in the isocyanate compound is generally 0.5 to 2 equivalents, particularly 0.8 to 1 equivalent to 1 equivalent of the hydroxyl group in the hydroxyl group-containing resin. It is preferable to be within the range of 1.2 equivalents. When the ratio of isocyanate groups in the isocyanate compound is less than 0.5 equivalent, the cross-linking density of the formed coating film is low and the physical properties of the coating film are insufficient. Although the performance is good, the drying property of the coating film is lowered and there is a problem in practicality.

  The coating composition of the present invention may further include various coating materials such as a solvent such as water or an organic solvent, a pigment dispersant, an anti-settling agent, a curing catalyst, an antifoaming agent, an antioxidant, and an ultraviolet absorber as necessary. Additives, extender pigments and the like can be appropriately blended.

  The coating composition of the present invention includes the above-described scaly aluminum pigments, talc pigments, colored pigments blended as necessary, solvents such as fiber-based resins, water or organic solvents, pigment dispersants, anti-settling agents , Curing catalyst, defoaming agent, antioxidant, various additives such as UV absorbers, one-component paints packed with extender pigments, etc. in the same container, but blended with isocyanate compound and if necessary It may be a two-component paint in which water, an organic solvent, or the like is packed in another container and mixed before painting.

  The coating composition of the present invention can be applied by a method known per se, such as rotary atomization coating, air spray, airless spray, etc., after adding water or an organic solvent to adjust the viscosity to an appropriate level for coating. The film thickness can be usually in the range of 5 to 60 μm, preferably 10 to 30 μm, based on the cured coating film, from the viewpoint of the concealing property of the substrate, the smoothness of the coating film, and the like. The coating film of the coating composition of the present invention can be usually crosslinked and cured at a temperature in the range of from room temperature to about 150 ° C.

  Next, the coating film forming method of the present invention will be described. In the coating film forming method of the present invention, the coating composition as described above is applied to a substrate.

  Base materials include metals such as iron, zinc, aluminum and magnesium, alloys containing these, molded products plated or vapor-deposited with these metals, and molded products made of glass, plastic, foam, etc. Can be mentioned. Furthermore, the base material can be appropriately subjected to degreasing treatment or surface treatment according to these materials. Furthermore, an undercoat film or an intermediate coat film can be formed on the substrate to form a substrate, and these are particularly preferable.

  The undercoat film is formed to conceal the surface of the material or impart anticorrosion and rustproofness to the material, and can be obtained by applying an undercoat paint, drying and curing. it can. The type of the undercoat paint is not particularly limited, and examples thereof include an electrodeposition paint and a solvent-type primer.

  The intermediate coating film is formed to conceal the surface of the material or the undercoat film, to provide adhesion or chipping resistance, or to adjust the lightness of the multilayer coating film. It can be obtained by applying an intermediate coating on the surface of the material or undercoat, drying and curing. The type of intermediate coating is not particularly limited, and known ones can be used. For example, an organic solvent-based or water-based intermediate coating containing a thermosetting resin composition and a color pigment as essential components can be preferably used. .

In particular, when an undercoat film or an intermediate coat film is formed as a substrate, the above-mentioned coating composition can be applied after heating the undercoat film and the intermediate coat film and crosslinking and curing. Alternatively, the undercoating film can be heated to form an intermediate coating film after crosslinking and curing, and the above-described coating composition can be applied in an uncured state. Alternatively, the above-described coating composition may be applied in a state where the undercoat coating film and the intermediate coating film are uncured.

  In the coating film forming method of the present invention, a color base coating film obtained by applying a color base coating material may be used as a base material. The color base coating film can be formed on the above-mentioned various materials, the undercoating film and the intermediate coating film.

  When the color base paint is applied onto the undercoat film or the intermediate coat film, the undercoat film or the intermediate coat film can be heated and applied after crosslinking curing. It is also possible to apply the color base paint in the uncured state.

  The color base paint in the present invention is applied to adjust the lightness and hue of a substrate, and is a paint containing a color pigment and a resin component which is a vehicle forming component. In the coating film forming method of the present invention, by making the base material a color base coating film adjusted to a specific color tone, even if the film thickness changes when the coating composition is applied, there is a difference in color tone and texture. When the surface is reduced or the surface of the coating film is damaged, the effect of making it less noticeable is achieved.

  The color base paint in the method of the present invention can be blended with a titanium oxide pigment as a coloring pigment.

  Titanium oxide pigments are widely used as white pigments because of their high refractive index, and there are rutile and anatase types depending on the crystal form, and any of these may be used in the present invention. From the point of view, the rutile type can be used. Moreover, you may use what processed the surface with inorganic compounds, such as a silica, a zirconium, and aluminum, for the purpose of improving a dispersibility and a weather resistance. In view of the hiding power of the coating film, it is preferable to use those having a primary particle diameter in the range of 100 to 400 nm, and more preferably in the range of 200 to 300 nm.

  When the color base paint contains a titanium oxide pigment, the content thereof is preferably 10 to 200 parts by mass with respect to 100 parts by mass of resin solids, which is a vehicle-forming component described later, in view of concealability and finish. Preferably, it is 20-180 mass parts.

  In addition to the titanium oxide pigment, a color pigment can be blended in the color base paint for the purpose of finely adjusting the hue and brightness of the multilayer coating film. The coloring pigment is not particularly limited, but specifically, inorganic pigments such as composite metal oxide pigments such as titanium yellow, transparent iron oxide pigments, azo pigments, quinacridone pigments, diketopyrrolo Pyrrole pigment, perylene pigment, perinone pigment, benzimidazolone pigment, isoindoline pigment, isoindolinone pigment, metal chelate azo pigment, phthalocyanine pigment, indanthrone pigment, dioxazine pigment, selenium Any one or more of organic pigments such as pigments, indigo pigments, carbon black pigments, and the like can be used in combination.

  In the present invention, when a color pigment other than the titanium oxide pigment is blended in the color base paint, the content is 0.01 to 30 parts by mass with respect to 100 parts by mass of the resin solid content from the point of brightness of the multilayer coating film. It is preferably within the range, more preferably within the range of 0.05 to 25 parts by mass.

  Specifically, the resin component that is a vehicle in the color base paint includes a base resin such as an acrylic resin, a polyester resin, an alkyd resin, and a urethane resin having a crosslinkable functional group such as a hydroxyl group, and a melamine resin as necessary. Examples include those used in combination with a crosslinking agent such as a urea resin and a polyisocyanate compound (including a block body), and these are used by dissolving or dispersing in a solvent such as an organic solvent and / or water.

  Furthermore, for color base paints, various additives such as solvents such as water or organic solvents, pigment dispersants, anti-settling agents, curing catalysts, antifoaming agents, antioxidants, UV absorbers, and extender pigments as necessary. Etc. can be appropriately blended.

  The color base paint can be applied by electrostatic coating, air spraying, airless spraying, etc., and the film thickness should be within the range of 10 to 150 μm based on the cured coating film. It is preferable from a point, More preferably, it exists in the range of 20-100 micrometers. The coating film made of the base paint can usually be crosslinked and cured at a temperature from room temperature to about 150 ° C.

  In the coating film forming method of the present invention, when a color base coating film obtained by applying a color base coating is used as a base material, the coating composition can be applied to the coating film after heat curing. Alternatively, it may be applied in an uncured state without being heat-cured.

  The coating composition of the present invention can be applied to the above-mentioned various substrates by methods such as electrostatic coating, air spraying, airless spraying, and the film thickness is in the range of 5 to 30 μm based on the cured coating film. Is preferable from the viewpoint of the smoothness of the coating film. Usually, after coating to a predetermined film thickness, it can be heated and dried and cured, but a clear coating described later can be applied even in an uncured state. The coating composition itself of the coating composition of the present invention can be crosslinked and cured at a temperature of about 50 to about 180 ° C. in the case of a baking and drying type, and usually in the case of a room temperature drying type or a forced drying type. It can be cured at a temperature of room temperature drying to about 80 ° C.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to only these examples. “Part” and “%” are based on mass. The number average molecular weight of the hydroxyl group-containing acrylic resin is measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

Production example 1: Production of hydroxyl group-containing acrylic resin (1) A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and dropping device was charged with 50 parts of xylene and 22 parts of butyl acetate and stirred and mixed. The temperature was raised to 120 ° C. Next, the following monomer / polymerization initiator mixture (1) was added dropwise to the reaction vessel maintained at the same temperature over 3 hours, and aging was performed for 1 hour after the completion of the addition. Thereafter, a mixture of 10 parts of xylene and 0.6 part of 2,2′-azobis (2-methylpropionitrile) was added dropwise over 1 hour and 30 minutes while maintaining the same temperature, and further aged for 2 hours, A hydroxyl group-containing acrylic resin (1) having a hydroxyl value of 82 mgKOH / g, a number average molecular weight of 20,000, and a resin solid content of 55% was obtained.
Monomer / polymerization initiator mixture (1):
Consists of 27 parts of methyl methacrylate, 23 parts of n-butyl acrylate, 19 parts of hydroxyethyl methacrylate, 30 parts of styrene, 1 part of acrylic acid and 2.5 parts of 2,2′-azobis (2-methylpropionitrile). blend.

Production example 2: Production of hydroxyl group-containing acrylic resin (2) A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and dropping device was charged with 50 parts of xylene and 22 parts of butyl acetate and stirred and mixed. The temperature was raised to 120 ° C. Next, the following monomer / polymerization initiator mixture (2) was added dropwise to the reaction vessel maintained at the same temperature over 3 hours, and aging was performed for 1 hour after the completion of the addition. Thereafter, a mixture of 10 parts of xylene and 0.6 part of 2,2′-azobis (2-methylpropionitrile) was added dropwise over 1 hour and 30 minutes while maintaining the same temperature, and further aged for 2 hours, A hydroxyl group-containing acrylic resin (2) having a hydroxyl value of 82 mgKOH / g, a number average molecular weight of 20,000, and a resin solid content of 55% was obtained.
Monomer / polymerization initiator mixture (2):
35 parts of styrene, 5 parts of methyl methacrylate, 33 parts of i-butyl methacrylate, 10 parts of 2-ethylhexyl acrylate, 17 parts of hydroxyethyl methacrylate, 1 part of acrylic acid and 2,2′-azobis (2-methylpropionitrile) A mixture consisting of 5 parts.
Example 1
Preparation of coating composition 1 85 parts (solid content) of the hydroxyl group-containing acrylic resin (1) obtained in Production Example 1, CAB 381 (cellulose acetate butyrate, Eastman Chemicals) previously dissolved in ethylene glycol monobutyl ether 15 parts (solid content), CR-8801 (resin-coated aluminum flake pigment, manufactured by Asahi Kasei Aluminum, average particle size 15.2 μm) 11 parts, Microace L-1 (talc pigment, manufactured by Nippon Talc Co., Ltd., average) The particle size is 5.1 μm), and 22.9 parts of Sumidur N3300 (trade name, hexamethylene diisocyanate, manufactured by Sumika Bayer Urethane Co., Ltd.) are added. % Coating composition 1 was prepared.
(Examples 2 to 8)
Preparation of coating composition 2-8 <br/> in the same manner as in the above coating composition 1 to prepare a coating composition 2-8 in compositions shown in Table 1.

(Comparative Examples 1-3)
In the same manner as the coating composition 1, coating compositions 9 to 11 having the compositions shown in Table 1 were prepared.

Preparation of color base paint Hydroxyl group-containing acrylic resin obtained in Production Example 1 (1) 100 parts (solid content), CR-95 (rutile titanium oxide pigment, manufactured by Ishihara Sangyo Co., Ltd.) 100 parts, MONARCH 1300 (carbon) 2 parts of black pigment (made by Columbia Carbon Co., Ltd.) are stirred and mixed, and 27 parts of Sumidur N3300 (trade name, hexamethylene diisocyanate, manufactured by Sumika Bayer Urethane Co., Ltd.) are added, diluted to an appropriate viscosity for coating, About 50% color base paint was prepared.

Preparation of clear coating material 100 parts of the hydroxyl group-containing acrylic resin (1) obtained in Production Example 1 (solid content) and 20 parts of CARPLEX CS-801 (fine powdered silica pigment, manufactured by Evonik) were stirred and mixed. 27 parts of Joule N3300 (trade name, hexamethylene diisocyanate, manufactured by Sumika Bayer Urethane Co., Ltd.) was added and diluted to an appropriate viscosity for coating to prepare a clear paint having a solid content of about 40%.
Preparation of test plate
Substrate 1: coated plate with an intermediate coating film formed on a steel plate (JISG 3141, size 400 × 300 × 0.8 mm) degreased and zinc phosphate treated with a cationic electrodeposition paint “ELECRON GT-10HT” ( Product name: Kansai Paint Co., Ltd., epoxy resin / polyamine cationic resin using block polyisocyanate compound as curing agent) electrodeposited to a film thickness of 20 μm based on the cured coating, 170 ° C. And then cured by crosslinking for 20 minutes to obtain an electrodeposition coating film.

Based on the cured coating film by air spraying on the resulting electrodeposition coated surface with an intermediate coating "Lugabake Intermediate Coating Gray" (trade name: manufactured by Kansai Paint Co., Ltd., polyester resin / melamine resin type, organic solvent type) It was coated to a film thickness of 30 μm, heated at 140 ° C. for 30 minutes to be crosslinked and cured, and a coated plate (base material 1) on which an intermediate coating film was formed was produced.
Substrate 2: Color base coating film The color base coating material is applied to the base material 1 by air spray so that the cured coating film has a thickness of 20 μm. The mixture was allowed to stand for 15 minutes and then heated at 80 ° C. for 30 minutes to dry and cure to obtain a color base coating film (base material 2).
Examples 10-15, 17, 18, Comparative Examples 4-6
In the configuration shown in Table 2, the coating compositions 1 to 12 were applied to the base material using an air spray so as to have a cured coating thickness of 20 μm, and after coating, about 15 in a laboratory at room temperature of about 20 ° C. After standing still, it was heated at 80 ° C. for 30 minutes using a hot air circulating drying oven to obtain a test plate.

Example 16
The coating composition 7 is applied to the substrate 1 using an air spray so as to have a cured coating thickness of 20 μm. After coating, the coating composition 7 is allowed to stand in a laboratory at a room temperature of about 20 ° C. for about 15 minutes, and then heated air circulation type A test plate was obtained by heating at 140 ° C. for 30 minutes using a drying furnace.
Comparative Example 7
The coating composition 11 was applied onto the substrate 1 using an air spray so that the cured coating film had a thickness of 20 μm. After painting, leave it in a laboratory at room temperature of about 20 ° C for about 15 minutes, heat and dry at 80 ° C for 30 minutes using a hot air circulating drying oven, and further use a clear paint as a cured coating film at 30 μm. After coating, it was allowed to stand in a laboratory at room temperature of about 20 ° C. for about 15 minutes, and then heated at 80 ° C. for 30 minutes to obtain a test plate.
Evaluation The test plate obtained above was evaluated according to the following criteria, and the results are shown in Table 2.
(60 ° specular gloss)
Using BYK-TriGloss manufactured by Big Chemie, the 60 ° specular gloss of the coating film was measured.
(Visual metallic evaluation)
Skilled engineers and designers who have been engaged in paint color design for industrial products for more than three years outdoors from 1 to 2 pm on sunny days change the observation angle and change the coating plate. The metal feeling was evaluated according to the following criteria.
4: Excellent metal feeling.
3: There is a metallic feeling.
2: There is almost no metal feeling.
1: There is no metal feeling.
(Smooth feeling)
The smoothness was evaluated by lightly touching the coated plate with a fingertip.
4: Excellent slip feeling.
3: There is a feeling of smoothness.
2: There is almost no slippery feeling.
1: There is no slippery feeling.

The coating composition and coating film forming method of the present invention can be applied to various industrial products, in particular, metallic frames and tanks of motorcycles.

Claims (6)

A coating composition for forming a topcoat coating film comprising a resin-coated scale-like aluminum pigment, a talc pigment and a fiber-based resin, the surface of which is coated with a resin composition The coating composition according to claim 1, wherein the average particle diameter of the scaly aluminum pigment is in the range of 5 to 40 µm. The coating composition according to claim 1 or 2, wherein the talc pigment is scaly and has an average particle diameter in the range of 3 to 15 µm . Furthermore, the cross-linking hardness is increased by a urethanization reaction containing a hydroxyl group-containing resin and an isocyanate compound.
The metallic paint composition of any one of Claims 1-3 containing the resin composition which can be converted . The coating-film formation method which coats the base material with the coating composition described in any one of Claims 1-4 . The coating film forming method according to claim 5, wherein the base material is a color base coating film obtained by applying a color base coating .