JP5809615B2 - Colored resin coated metal plate - Google Patents

Description

  The present invention relates to a colored resin-coated metal plate used for casings and interior / exterior parts of automobiles and household electrical appliances, steel plate and other exterior plate materials and building materials, and more specifically, coloring without concealing the original plate Thus, the present invention relates to a colored resin-coated metal plate excellent in design, in which a pigment color and a metallic tone are beautifully combined.

Conventionally, zinc-based plated steel sheets have been widely used for automobiles, electrical products, building materials, and the like. However, the zinc-based plated metal sheet is insufficient in corrosion resistance and adhesion to the paint as it is, so if it is subjected to non-chromate treatment or phosphate treatment and further high corrosion resistance is required, these chemical conversions are required. A resin film is provided on the treatment layer. On the other hand, from the viewpoint of the beauty of the appearance and the degree of perfection as a product, the uppermost resin film is required to have the color tone and high designability required by the user. In general, inorganic pigments or organic pigments are used to color the resin, but it is usually assumed that the original plate is concealed. In order to conceal the original plate and obtain a beautiful appearance, a coating film having an adhesion amount of 10 g / m ² or more is usually required, and the cost of the coating and a long baking process are required, resulting in an increase in manufacturing cost.

  For this reason, it has been attempted to color with a translucent resin thin film without concealing the original plate. For example, Patent Document 1 discloses a colored resin-coated metal plate in which a resin coating film containing a color pigment is formed on a chromate-treated original plate. However, currently, non-chromate is the mainstream, and the technique described in Patent Document 1 cannot be applied to a non-chromic metal plate as it is.

JP-A-9-122578

  In consideration of the above circumstances, the present invention is a colored resin-coated metal plate that has a high design property in which a non-chromate original plate is colored with a thin film resin that can be manufactured even on a high-speed line, and a metallic tone and a colored resin are combined. Offering was raised as an issue.

The colored resin-coated metal plate of the present invention is a non-chromate metal plate having a colored resin layer having a thickness of 0.3 to 2.2 μm on at least one surface, and the colored resin layer contains one or more pigments. In addition, when the 60 ° specular gloss measured from the colored resin layer side is x and the average reflectance of 500 to 600 nm is y, the following formulas (1) and (2) are satisfied.
(1) y ≧ −0.19x + 23.0
(2) y ≧ 10

  The colored resin layer preferably contains at least one pigment dispersant selected from the group consisting of a water-soluble acrylic resin, a water-soluble styrene acrylic resin and a nonionic surfactant, and contains a polyamide thixotropic agent. It may be.

The colored resin-coated metal plate of the present invention preferably further satisfies the following formula (3).
(3) y ≧ −0.27x + 41.3

It is preferable that the colored resin layer contains a yellow pigment, and this yellow pigment is any of benzimidazolone, quinoxaline, and isoindolinone.
The average reflectance of 500 to 600 nm of the original plate before forming the colored resin layer is preferably 50% or more.

  The present invention also includes a colored resin-coated metal plate provided with a clear coating film on the colored resin layer. In this case, the film thickness of the clear coating film is preferably 0.4 to 4.5 μm.

  According to the present invention, it is possible to provide a colored resin-coated metal sheet having a high design property in which a metallic tone obtained by coloring a non-chromate original sheet with a thin film resin and a colored resin are combined at low cost. In addition, the colored resin-coated metal plate having a clear coating on the uppermost layer has excellent wear resistance and tape peel resistance.

  Therefore, the colored resin-coated metal plate of the present invention can be applied to various uses such as home appliances, building materials, and automobile parts.

It is a graph which shows the relationship between 60 degree specular gloss of a coloring resin coating metal plate, and the average reflectance of 500-600 nm.

  In order to solve the above-mentioned problems, the present inventors have performed color coating with a translucent thin film resin and studied the appearance of the resulting colored resin-coated metal plate. As a result, it has been found that adhesion of foreign matter to the original plate, surface irregularities, wrinkles, etc. have a great influence on the appearance after coating, and appearance defects easily occur. This appearance defect is not only due to the presence of wrinkles, but it is also difficult for the colored resin to enter the recesses of the wrinkles, so that the colored resin stays around the wrinkles and has a crater-like appearance (approximately 2 mm in diameter). It becomes bad. In the case of thick film coating, the crater can be filled and the appearance does not deteriorate, but in the case of thin film coating, a crater-like appearance defect remains, which is a problem. Therefore, focusing on the light absorptivity of the pigment and the specific visual sensitivity of the human eye, a guideline for making the crater-like appearance defect inconspicuous was studied, and the present invention was achieved.

  The specific visibility is a numerical value representing the strength with which the human eye feels the brightness of light at each wavelength. In bright places, human eyes tend to feel light of 500 to 600 nm with a peak at a wavelength of 555 nm. Therefore, in the present invention, the 60 ° specular gloss x of the colored resin-coated metal plate and the average reflectance y of 500 to 600 nm were measured, and the following formulas (1) and (2) were derived from the relationship between the two. FIG. 1 is a graph showing the relationship between 60 ° specular gloss and an average reflectance of 500 to 600 nm.

(1) y ≧ −0.19x + 23.0
If y is larger than the right side of the above formula (1), the light absorption by the pigment is suppressed, the average reflectance of 500 to 600 nm which is felt bright to human eyes is large, and the 60 ° specular gloss is also high. Since it is high, it is a region where crater-like appearance defects are hardly noticeable.

(2) y ≧ 10
In order to make use of the metallic tone of the original plate, y needs to be 10 or more, and if the average reflectance y is smaller than 10, depending on the pigment type (eg, red, blue, bluish purple, red (Purple etc.) Since the original plate is concealed, it cannot be said that it has already developed high metallic design.

  The 60 ° specular gloss and the average reflectance of 500 to 600 nm are measured from the colored resin layer side. As a measuring instrument, a 60 ° specular gloss is a gloss meter (for example, a gloss meter “VG-2000” manufactured by Nippon Denshoku Industries Co., Ltd.), and an average reflectance is a spectral color difference meter (for example, a simultaneous photometric spectroscope manufactured by Nippon Denshoku Industries Co., Ltd.). The average reflectance of 500 to 600 nm is measured at a wavelength of 10 nm (measurement number: 11), and (total reflectance for each wavelength) is measured with a color difference meter “SQ-2000”). / (Number of measurements 11) = average reflectance.

In FIG. 1, a region satisfying the following formula (3) is more preferable.
(3) y ≧ −0.27x + 41.3

  If it is this area | region, a crater-like external appearance defect will not be conspicuous and it will become a colored resin coating metal plate which was further excellent in design nature.

  Hereinafter, the constituent material of the colored resin-coated metal plate of the present invention will be described.

[Original plate]
The original plate of the colored resin-coated metal plate of the present invention is a cold-rolled steel plate, a hot-dip galvanized steel plate (GI), an alloyed hot-dip Zn-Fe-plated steel plate (GA), an alloyed hot-dip Zn-5% Al-plated steel plate (GF). ), Electro-pure galvanized steel plate (EG), electro-Zn-Ni plated steel plate, aluminum plate, titanium plate, galvalume steel plate, etc., and non-chromate ones.

The original plate may be subjected to a phosphoric acid-based chemical conversion treatment. In particular, as shown in Japanese Patent Application Laid-Open No. 2005-264212, chemical conversion treatment is performed using an acidic aqueous solution containing colloidal silica and an aluminum phosphate compound. It is preferable to keep it. When an acidic aqueous solution containing colloidal silica and an aluminum phosphate salt compound is used as the chemical conversion treatment solution, the surface of the zinc-based plating layer is etched by the acidic aqueous solution, and the surface of the zinc-based plating layer is hardly soluble among aluminum phosphates. A reaction layer mainly composed of AlPO ₄ or Al ₂ (HPO ₄ ) ₃ (which is hardly soluble in water or an alkaline aqueous solution) is formed. As the silica fine particles are deposited and taken into the reaction layer, the aluminum phosphate and the silica fine particles are combined and integrated. In addition, a dense reaction layer is formed with the zinc-based plating layer roughened by etching, and the bond with the resin coating formed on the reaction layer is also dense and strong. In addition, when the acidic aqueous solution contains a water-soluble resin such as polyacrylic acid, the deposited state of the silica fine particles in the obtained reaction layer can be further strengthened.

  The original plate preferably has an average reflectance of 500 to 600 nm of 50% or more. If an original plate having a high reflectivity is used, the reflectivity after forming a translucent colored resin layer that does not conceal the original plate is increased, and crater-like appearance defects are less noticeable. The thickness of the original plate is not particularly limited, but is preferably about 0.3 to 1 mm.

[Pigment dispersant]
In the present invention, the dispersibility of the pigment is also one of the important factors for increasing the reflectance of the colored resin-coated metal plate and reducing the crater-like appearance defect. In the colored resin layer forming resin composition, It is preferable to add a pigment dispersant. A suitable pigment dispersant is at least one selected from the group consisting of a water-soluble acrylic resin, a water-soluble styrene acrylic resin, and a nonionic surfactant. When these are used, the pigment dispersant remains in the colored coating film.

As a water-soluble acrylic resin and a water-soluble styrene acrylic resin, it is preferable that an acid value is about 50-300. Specifically, the water-soluble acrylic resin is an alkali neutralized product of a copolymer of 50% by mass or less of an unsaturated carboxylic acid such as (meth) acrylic acid and (meth) acrylic acid ester. The water-soluble styrene acrylic resin is an alkali neutralized product of a copolymer of styrene and / or methylstyrene 50 to 95% by mass and (meth) acrylic acid or maleic acid. Other examples of the copolymerizable monomer include a sulfonic acid group-containing monomer, and a (meth) acrylic acid ester may also be used in a water-soluble styrene acrylic resin. The number average molecular weight of these resins is preferably about 2500 to 15000.

  Nonionic surfactants are commercially available from various manufacturers, and any nonionic surfactant can be used.

  Among water-soluble acrylic resins, water-soluble styrene acrylic resins, and nonionic surfactants, those having a benzene ring or a naphthalene ring structure are preferable. In this sense, a water-soluble styrene acrylic resin, a nonion having a benzene ring or a naphthalene ring structure is preferable. A surfactant is preferred.

  Since the pigment dispersant is often added to the pigment in advance, the pigment dispersant can be contained in the resin composition by using a pigment described later. The pigment dispersant is preferably used in an amount of 0.05 to 6.2% by mass in the colored resin layer. If the amount is too large, the corrosion resistance and chemical resistance may be lowered. If the amount is too small, the dispersibility of the pigment may be inferior.

[Thixotropic agent]
Since the coating material (resin composition for forming colored resin layer) used for thin film coating has a low solid content, the coating film immediately after being applied on the metal plate is not coated until the medium water is completely dried. It was found that resin components and pigments contained in the film move in the coating film. In particular, it was also found that the pigment tends to segregate in the portion of the metal plate around the heel where the paint tends to accumulate, which makes the crater-like appearance defect more conspicuous. For this reason, in this invention, it is a preferable embodiment to add a thixotropic agent in the resin composition for colored resin layer formation. Particularly preferred are polyamide-based and water-based thixotropic agents. Polyamide is a polymer in which a large number of monomers are bonded by amide bonds, and is adsorbed to the pigment by hydrogen bonds. Therefore, it is considered that the dispersion stability of the pigment is increased by steric hindrance of the adsorbed polymer. Moreover, since a network structure is formed in the coating film by hydrogen bonding between polyamide molecular chains, it is considered that migration and segregation of the pigment are prevented. The polyamide thixotropic agent is preferably added so that the viscosity of the resin composition for forming the colored resin layer is about 10 to 20 seconds in Ford Cup # 4, and is 0.5 to 3% by mass in terms of solid content. The degree is preferred. Such a polyamide thixotropic agent for water-based paints is available from Enomoto Kasei Co., Ltd., for example, as Disparon (registered trademark) AQ series.
In the AQ series, a polyamide represented by the following chemical formula is used as a main component, and the molecular weight of the polyamide is 3000 or less. R and R ′ in the chemical formula are alkyl groups.

[Aqueous polyurethane resin for forming colored resin layer]
The colored resin-coated metal plate of the present invention has a colored resin layer formed on one side or both sides of the original plate, and it is preferable to use an aqueous polyurethane resin as the base resin. As the aqueous polyurethane resin, a carboxyl group-containing polyurethane resin having an acid value of 10 to 60 mgKOH / g described in JP-A-2005-199673 can be suitably used. This carboxyl group-containing polyurethane resin is an aqueous dispersion of a polyurethane resin synthesized by essentially using a polyol having a carboxyl group. As raw materials, 1,4-cyclohexanedimethanol, polytetramethylene glycol having an average molecular weight of about 400 to 4000, a polyol component such as a polyol having a carboxyl group such as dimethylolpropionic acid, tolylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane Isocyanate components such as diisocyanate are used. The chain extender is preferably a polyamine such as ethylenediamine.

A known method can be used to prepare an aqueous liquid of the carboxyl group-containing polyurethane resin used in the present invention. For example, the carboxyl group of the carboxyl group-containing urethane prepolymer is neutralized with a base, There are a method of emulsifying and dispersing to chain extension reaction, a method of emulsifying and dispersing a carboxyl group-containing polyurethane resin with high shear force in the presence of an emulsifier, and the like.

  First, a relatively low molecular weight carboxyl group-containing isocyanate group-terminated urethane prepolymer is prepared by using the above-described polyisocyanate and the above-described polyol so that the isocyanate group becomes excessive in the NCO / OH ratio. Although the temperature which synthesize | combines a urethane prepolymer is not specifically limited, It can synthesize | combine at the temperature of 50-200 degreeC.

  After completion of the urethane prepolymer reaction, the obtained carboxyl group-containing isocyanate group-terminated urethane prepolymer can be emulsified and dispersed in water by neutralization with a base. The neutralizing agent is not particularly limited, and ammonia; tertiary amines such as triethylamine and triethanolamine; alkali metal hydroxides such as sodium hydroxide and potassium hydroxide can be used. Preferably, triethylamine is used.

  After emulsifying and dispersing the carboxyl group-containing isocyanate group-terminated urethane prepolymer, a chain extension reaction can be carried out in water using a chain extender such as polymian. The chain extension reaction can be appropriately carried out before emulsification dispersion, simultaneously with emulsification dispersion, or after emulsification dispersion, depending on the reactivity of the chain extender used.

[Aqueous polyurethane resin composition for forming colored resin layer]
When forming a colored coating film, it is preferable to use silica particles as a composition together with the aqueous polyurethane resin. Silica particles are preferably about 10 to 30% by mass in 100% by mass of the composition. As the silica particles, colloidal silica having a surface area average particle size of 10 to 20 nm is preferable, and such colloidal silica is available as SNOWTEX (registered trademark) 40 from Nissan Chemical Industries.

  The aqueous polyurethane resin composition may contain a wax. Industrially preferred are polyethylene wax, polypropylene wax, modified wax, copolymer wax with ethylene or propylene, ethylene copolymer wax, oxides thereof, derivatives having a carboxyl group, etc., and acids. Paraffin wax, carnauba wax and the like to which groups have been added. The wax is preferably about 0.5 to 20% by mass in 100% by mass of the composition.

  In order to crosslink the aqueous polyurethane resin, a crosslinking agent may be added. From the viewpoint of reactivity, an epoxy-based crosslinking agent is preferable, and sorbitol polyglycidyl ether, (poly) glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, (poly) ethylene Examples include polyglycidyl ethers such as glycol diglycidyl ether, polyglycidyl amines, and the like. As such an epoxy-based crosslinking agent, Epicron (registered trademark) CR75, CR5L, and the like manufactured by DIC are available. It is preferable that a crosslinking agent shall be about 5-20 mass parts with respect to 100 mass parts of resin.

[Aqueous polyethylene resin composition for forming colored resin layer]
In the colored resin-coated metal plate of the present invention, an aqueous polyethylene resin composition may be used as the base resin composition. Examples of the aqueous polyethylene resin include 60 to 80 parts by mass of an inorganic component composed of a plurality of types of colloidal silica having different surface area average particle diameters described in JP2011-92837A, and olefin-α, β-. 20-40 parts by mass of a resin component composed of an unsaturated carboxylic acid copolymer, an α, β-unsaturated carboxylic acid polymer, and an acrylic-modified epoxy resin, and the total of the inorganic component and the resin component What contains 5-15 mass parts of glycidoxy group containing silane coupling agents and 0.5-3 mass parts of metavanadates with respect to 100 mass parts is further preferable.

  As the colloidal silica, those having a surface area average particle diameter of 4 to 6 nm and those having a surface area average particle diameter of 10 to 20 nm are preferably used in combination, and the former includes “Snowtex (registered trademark) XS” manufactured by Nissan Chemical Industries, Ltd. Examples of the latter include the above-mentioned “Snowtex (registered trademark) 40”. The mixing ratio of the two is not particularly limited, but the same amount is preferable.

  The olefin-α, β-unsaturated carboxylic acid copolymer is a copolymer of an olefin and an α, β-unsaturated carboxylic acid, and an olefin-derived structural unit such as ethylene or propylene is contained in the copolymer. It means that it is 50% by mass or more (that is, the structural unit derived from α, β-unsaturated carboxylic acid such as (meth) acrylic acid is 50% by mass or less). An ethylene-acrylic acid copolymer is particularly preferable. The “α, β-unsaturated carboxylic acid” includes “α, β-unsaturated carboxylic acid salt” in which a part of the carboxyl group is neutralized with a neutralizing agent.

  The α, β-unsaturated carboxylic acid polymer is a polymer (including a copolymer) obtained using α, β-unsaturated carboxylic acid as a monomer, and is derived from α, β-unsaturated carboxylic acid. In the polymer is 90% by mass or more. Polymaleic acid is particularly preferable.

  The mixing ratio of the olefin-α, β-unsaturated carboxylic acid copolymer and the α, β-unsaturated carboxylic acid polymer is preferably about 100: 1 to 100: 5.

  It is preferable to use an aqueous dispersion as the acrylic-modified epoxy resin, and such an aqueous acrylic-modified epoxy resin is commercially available. For example, “MODEPICS (registered trademark) 301” and “MODEPICS (registered trademark) manufactured by Arakawa Chemical Industries, Ltd. Trademark) 302 "," MODEPICS (registered trademark) 303 "," MODEPICS (registered trademark) 304 ", and the like are available. The acrylic-modified epoxy resin is preferably about 2% by mass to 15% by mass in 100% by mass of the resin component.

Examples of the silane coupling agent having a glycidoxy group include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, vinyltris (β-methoxyethoxy) silane, and the like.

Examples of the metavanadate include sodium metavanadate (NaVO ₃ ), ammonium metavanadate (NH ₄ VO ₃ ), and potassium metavanadate (KVO ₃ ).

  The aqueous polyethylene resin composition may contain a carbodiimide group-containing compound. Examples of commercially available carbodiimide group-containing compounds include N, N-dicyclohexylcarbodiimide, N, N-diisopropylcarbodiimide and the like, and polycarbodiimide (polymer having a plurality of carbodiimide groups in one molecule) manufactured by Nisshinbo Co., Ltd. One “Carbodilite®” series may be mentioned. The grades of “Carbodilite (registered trademark)” include water-soluble “SV-02”, “V-02”, “V-02-L2”, “V-04”, and emulsion type “E-01”. , “E-02” and the like.

  The amount of the carbodiimide group-containing compound is set according to the amount of the olefin-α, β-unsaturated carboxylic acid copolymer and α, β-unsaturated carboxylic acid polymer which are crosslinking partners. About 0.5-20 mass parts is preferable with respect to these 100 mass parts in total.

[Pigment]
Examples of pigment types for coloring each of the following colors include: red: insoluble azo (naphthol and anilide) or soluble azo pigments, inorganic pigments such as bengara, cadmium red, and red lead Pigments, yellow: insoluble azo (naphthol and anilide), soluble azo, quinacridone, benzimidazolone, quinoxaline, isoindolinone and other organic pigments, chrome yellow, cadmium yellow, nickel titanium yellow, Inorganic pigments such as yellow and strontium chromate, green: organic phthalocyanine pigments, blue: organic phthalocyanine pigments, dioxazine pigments, inorganic pigments such as bitumen, ultramarine blue, cobalt blue, emerald green, orange: benzimidazolone , Organic pigments such as pyrazolone, black: aniline black, Organic pigments such as glossin, inorganic pigments such as carbon black, inorganic pigments such as iron black, white: inorganic pigments such as titanium oxide, calcium carbonate, zinc oxide, barium sulfate, lithopone, lead white, etc. . Of the above color pigments, those with the same color but different chemical structures, or by mixing two or more color pigments of different colors at an appropriate blending ratio, gray, brown, purple, red purple, blue purple, orange, golden color It can be colored to a desired color. Among yellow pigments, benzimidazolone, quinoxaline, and isoindolinone are apt to be yellowish after the accelerated weather resistance test, and are preferred as pigments.

  Commercially available as dispersed pigments together with the pigment dispersant described above are black: “AF Black E-2B” (manufactured by Dainichi Seika Kogyo Co., Ltd.) made of carbon black and water-soluble acrylic resin, carbon black and water-soluble styrene. "SA Black DY-6" made of acrylic resin (manufactured by Mikuni Dye), "PSM black 12578" made by carbon black and nonionic surfactant (manufactured by Mikuni Dye), white: titanium oxide and water-soluble acrylic resin "AF White E-3D" (manufactured by Dainichi Seika Kogyo Co., Ltd.), "SA White NF-3769" (manufactured by Mikuni Dye Co., Ltd.) made of titanium oxide and water-soluble styrene acrylic resin, titanium oxide and nonionic surfactant "GP White 13600" (made by Gokoku Color Co., Ltd.), blue: made of cyanine dye and water-soluble acrylic resin "AF Blue E-2B" (manufactured by Dainichi Seika Kogyo Co., Ltd.), "SA Blue DY-12" (manufactured by Gokoku Color Co., Ltd.) consisting of a cyanine dye and a water-soluble styrene acrylic resin, a cyanine dye and a nonionic surfactant "PSM Blue HB" (manufactured by Gokoku Color Co., Ltd.), yellow: "AF Yellow E-12" (manufactured by Dainichi Seika Kogyo Co., Ltd.) comprising disazo dye and water-soluble acrylic resin, disazo dye and water-soluble styrene acrylic “SA Yellow RS” made of resin (manufactured by Gokoku Color Co., Ltd.), “PSM Yellow RS” made by disazo dye and nonionic surfactant (made by Gokoku Color Co., Ltd.), benzimidazolone dye and water-soluble acrylic resin "AF Yellow E-26" (manufactured by Dainichi Seika Kogyo Co., Ltd.), "NAF1012 Yellow" consisting of a benzimidazolone dye and a water-soluble acrylic resin ( Nissei Kagaku Kogyo Co., Ltd.), “SA Yellow GLN-K” (made by Gokoku Color Co., Ltd.) consisting of disazo dye and water-soluble styrene acrylic resin, “SA Yellow” consisting of benzimidazolone dye and water-soluble styrene acrylic resin 13755 "(manufactured by Gokoku Color Co., Ltd.)," SA Yellow A1559 "(made by Gokoku Color Co., Ltd.) consisting of a quinoxaline dye and a water-soluble styrene acrylic resin, and" PSM Yellow 10G "consisting of a disazo dye and a nonionic surfactant. (Manufactured by Gokoku Color Co., Ltd.), “PSM Yellow 12298” (made by Gokoku Color Co., Ltd.) consisting of an isoindolinone dye and a nonionic surfactant, green: “AF Green E-” made of a cyanine dye and a water-soluble acrylic resin 1 "(manufactured by Dainichi Seika Kogyo Co., Ltd.)," SA Green DY-4 "comprising a cyanine dye and a water-soluble styrene acrylic resin ( Gokoku Dye Co., Ltd.), Magenta: "AF Red E-17" (made by Dainichi Seika Kogyo Co., Ltd.) made of quinacridone dye and water-soluble acrylic resin, "PSM Pink" made of quinacridone dye and nonionic surfactant KR "(manufactured by Gokoku Color Co., Ltd.), blue purple:" SA blue purple # 800 "(produced by Gokoku Color Co., Ltd.) made of a dioxazine pigment and a water-soluble styrene acrylic resin.

It is necessary to adjust the addition amount of these commercially available pigments according to the thickness of the colored resin layer so as to satisfy the formulas (1) and (2), preferably the formula (3). This is because, in a thin film having a film thickness of 3 μm or less, for example, the average reflectance at 500 to 600 nm decreases as the amount of pigment added increases. Moreover, in order to utilize the metallic tone of the original plate for design, it is necessary to suppress the addition amount of a pigment having a large hiding power. For this reason, the upper limit of the pigment content is preferably about 20% by mass.

[Thickness of colored resin layer]
In the present invention, the thickness of the colored resin layer is 0.3 to 2.2 μm. If it is thinner than 0.3 μm, the coloring effect and the design property are not exhibited. A thickness exceeding 2.2 μm is not preferable because it is contrary to the object of the present invention to reduce the cost by using a thin film.

[Colored resin layer forming resin composition and coating method thereof]
In order to prepare the composition for forming a colored resin layer used in the present invention, each component may be mixed. If necessary, the components are preferably emulsified together or separately and mixed as an aqueous dispersion.

  The method for applying the resin composition to the original plate is not particularly limited, and a bar coater method, a roll coater method, a spray method, a curtain flow coater method, or the like can be employed. After application, it is preferable to heat and dry at about 80 to 130 ° C.

[Clear coating]
The colored resin-coated metal plate of the present invention may have a clear coating film on the colored resin layer. The material of the clear coating is not particularly limited, but examples thereof include polyester resins, acrylic resins, urethane resins, polyolefin resins, fluorine resins, silicone resins, epoxy resins, and mixtures or modified resins of these resins. Can be mentioned. Considering hardness, abrasion resistance, tape peel resistance, etc., an organic solvent soluble type (amorphous) polyester resin is preferred. As the organic solvent-soluble polyester resin, “Byron (registered trademark)” series manufactured by Toyobo Co., Ltd. is preferable in that a wide variety of types can be obtained.

  The polyester resin may be crosslinked with a melamine resin or the like. As the melamine resin, there are “Sumimar (registered trademark)” series manufactured by Sumitomo Chemical Co., Ltd. and “Cymel (registered trademark)” series manufactured by Mitsui Cytec. In addition, it is preferable to mix | blend a crosslinking agent so that a crosslinking agent may be 5-30 mass parts with respect to 100 mass parts of resin in consideration of hardness, abrasion resistance, tape peeling resistance, etc. As the coating method, the same method as described above can be adopted. The film thickness of the clear coating film is not particularly limited because it hardly affects the reflectance, but is preferably about 0.4 to 4.5 μm.

  The present invention will be described in more detail with reference to the following examples. However, the following examples are not intended to limit the present invention, and modifications within the scope of the present invention are included in the present invention. Hereinafter, “part” indicates “part by mass”, and “%” indicates “% by mass”. Moreover, the evaluation method used in the Example is as follows.

[Evaluation method]
(A) Presence / absence of crater-like appearance The colored resin layer-formed surface of the painted sample (50 × 120 mm) was photographed with a digital camera, and the obtained photograph was visually observed on a personal computer. The number of craters within an arbitrary 30 × 30 mm range was counted and evaluated according to the following criteria.
☆: No crater, ◎: Less than 5, ○: 5 or more and less than 10, △: 10 or more and less than 30, x: 30 or more

(B) 60 ° specular gloss The colored resin layer-formed surface of the coated sample (50 × 120 mm) was measured using a gloss meter “VG-2000” manufactured by Nippon Denshoku Industries Co., Ltd.

(C) Average reflectance of 500-600 nm About the colored resin layer formation surface of a coating sample (50x120 mm), it measured using the Nippon Denshoku Industries Co., Ltd. simultaneous photometry type | system | group spectral color difference meter "SQ-2000". For the average reflectance of 500 to 600 nm, the reflectance was measured at a wavelength of 10 nm (measurement number: 11), and (total reflectance for each wavelength) / (measurement number 11) = average reflectance.

(D) Formulas (1) to (3) Whether or not the following formulas (1) to (3) are satisfied was evaluated from the 60 ° specular gloss and the average reflectance of 500 to 600 nm. When satisfied, it was marked with ◯, and when not satisfied, it was marked with ×.
(1) y ≧ −0.19x + 23.0
(2) y ≧ 10
(3) y ≧ −0.27x + 41.3

(E) Abrasion resistance Using a two-coat paint sample (50 x 100 mm) in which a clear coating film is laminated on a colored resin layer, using an eraser (manufactured by Right River Rubber Factory Co., Ltd.) with a Haydon testing machine, The surface of the sample was rubbed at a load of 16.1 ± 0.05 N, a stroke length of 25.4 mm, and a speed of 1 reciprocation / 2 seconds, and the number of times until the original substrate was seen (the number of wear) was measured.

(F) Processed part adhesion Using a 2-coat coating sample (50 x 50 mm) in which a clear coating film is laminated on a colored resin layer, 2T bending is performed at room temperature, and a cellophane tape is applied to the bent part to perform a peeling test. Went. The evaluation was made with ○ as no peeling, Δ as a peeling area of 50% or less, and × as a peeling area exceeding 50%.

[Original plate]
Five types of original plates shown in Table 1 were used. The original plate was subjected to non-chromate chemical conversion treatment. As processing solutions, polyacrylic acid (reagent, average molecular weight 25000), aluminum biphosphate (manufactured by Nippon Chemical Industry Co., Ltd., solid content 50 mass%), colloidal silica (Nissan Chemical Co., Ltd. Snowtex (registered trademark); ST-O ), An acidic aqueous liquid mixed with a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd .; KBM-403; solid content 100%) was used. The blending ratio of each component was 4.4% polyacrylic acid, 57.8% aluminum biphosphate, 31.1% colloidal silica, and 6.7% silane coupling agent in terms of solid content. This treatment solution is sprayed onto an alkali degreased original plate by spraying, the excess solution is removed with a ringer roll, washed with water at a spray pressure of 100 kPa for 5 seconds, and dried at 40 ° C. A chromate treatment layer was provided.

[Pigment]
The following color pigments (including dispersants) were used.

Preparation Example 1 (Preparation of a carboxyl group-containing polyurethane resin aqueous solution and preparation of a polyurethane-based colored resin layer forming resin composition)
A stirrer, thermometer, temperature controller in the synthesizer, 60 parts polytetramethylene ether glycol (average molecular weight 1000; manufactured by Hodogaya Chemical Co., Ltd.) as the polyol component, 14 parts 1,4-cyclohexanedimethanol, dimethylolpropion 20 parts of acid was added, and 30 parts of N-methylpyrrolidone was added as a reaction solvent. 104 parts of tolylene diisocyanate was charged as an isocyanate component, heated to 80 ° C. to 85 ° C., and reacted for 5 hours. The obtained prepolymer had an NCO content of 8.9%. Further, 16 parts of triethylamine was added for neutralization, a mixed aqueous solution of 16 parts of ethylenediamine and 480 parts of water was added, and a chain extension reaction was carried out while emulsifying at 50 ° C. for 4 hours to obtain an aqueous polyurethane resin liquid (nonvolatile Resin component 29.1%, acid value 41.4).

  Carboxylic group-containing polyurethane resin aqueous solution obtained above, colloidal silica (ST-40 manufactured by Nissan Chemical Industries, Ltd .: particle size 10-20 nm), epoxy-based crosslinking agent (manufactured by DIC: Epicron (registered trademark) CR75), polyethylene wax Particles (Mitsui Chemicals Co., Ltd .: Chemipearl (registered trademark) W-700, average particle size 1 μm, softening point 132 ° C.), various pigments described above, polyamide thixotropic agent (manufactured by Enomoto Kasei Co., Ltd .: Disparon for water-based paints (registered trademark) ) AQ-607) was mixed to prepare a polyurethane colored resin layer forming resin composition.

  The blending ratio of each component is 58.5 to 73.5 parts of a carboxyl group-containing polyurethane resin, 20 parts of colloidal silica, 2 parts of an epoxy-based cross-linking agent, 3.5 parts of polyethylene wax particles, and a polyamide-based thixotropic in terms of solid content. It mix | blended so that it might become 1 to 15 parts of 0 or 1.0 part of agents, and various pigments (a dispersing agent included). The amount of the thixotropic agent and the pigment was changed so that the resin amount was changed and the total amount was 100 parts.

Preparation Example 2 (Preparation of aqueous polyethylene resin and preparation of resin composition for forming polyethylene-based colored resin layer)
In an autoclave having an emulsification facility equipped with a stirrer, a thermometer, and a temperature controller, an ethylene-acrylic acid copolymer (manufactured by Dow Chemical Company: Primacol (registered trademark)) as an olefin-α, β-unsaturated carboxylic acid copolymer. ) 5990I, acrylic acid unit: 20% by mass, Mw: 20,000, MI: 1300, acid value: 150) 200.0 parts, α, β-unsaturated carboxylic acid polymer as polymaleic acid aqueous solution (manufactured by NOF Corporation) : Nonpole (registered trademark) PMA-50W, Mw: about 1100 (polystyrene equivalent), 50% product) 8.0 parts, 35.5 parts triethylamine (0.63 with respect to the carboxyl group of the ethylene-acrylic acid copolymer) Equivalent), 6.9 parts of 48% NaOH aqueous solution (0.15 equivalent to the carboxyl group of the ethylene-acrylic acid copolymer), Oil fatty acid (Harima Kasei Co., Ltd.: HARTALL FA3) 3.5 parts, and sealed with ion exchange water 792.6 parts, after 3 hours high speed stirring at 0.99 ° C. and 5 atm, and cooled to 30 ° C..

  Next, 10.4 parts of a glycidoxy group-containing silane coupling agent (Momentive Performance Materials (former name: GE Toshiba Silicone): TSL8350, γ-glycidoxypropyltrimethoxysilane), a carbodiimide group-containing compound (Nisshinbo Co., Ltd.) (Product: Carbodilite (registered trademark) SV-02, polycarbodiimide, Mw: 2,700, solid content 40%) 31.2 parts, 72.8 parts of ion-exchanged water were added and stirred for 10 minutes. An emulsion (emulsion) of an acid copolymer and polymaleic acid was prepared (solid content concentration of about 20%, measured according to JIS K6833).

  Colloidal silica (A) (manufactured by Nissan Chemical Industries, Ltd .: ST-XS (solid content concentration 20%)) having a surface area average particle size of 4 to 6 nm (notified value) and a surface area average particle size of 10 to 20 nm (notified) Value) colloidal silica (B) (manufactured by Nissan Chemical Industries, Ltd .: ST-40 (solid content concentration 40%)) was added in order and mixed well, and then a glycidoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM403 (solid content concentration 100%)), and then sodium metavanadate (manufactured by Shinsei Chemical Industry Co., Ltd., sodium metavanadate (solid content concentration of about 66%)) was added as a metavanadate. To this mixture, an acrylic-modified epoxy resin (manufactured by Arakawa Chemical Industry Co., Ltd., MODEPICS (registered trademark) 302 (solid content concentration 33.5%)) was further added to prepare a polyethylene resin composition. The blending ratio of each component is, in terms of solid content, 25.7% ethylene-acrylic acid copolymer and polymaleic acid, 1.3% acrylic modified epoxy resin, 31.5% colloidal silica (A), colloidal silica (B 31.5%, silane coupling agent 9.0%, sodium metavanadate 1.0%.

Polyethylene wax (Mitsui Chemicals Co., Ltd .: Chemipearl (registered trademark) W-900, average particle size 0.6 μm, softening point 132 ° C.), the above various pigments,
The above-mentioned polyamide thixotropic agent (Disparon AQ-607) was mixed to prepare a resin composition for forming a polyethylene colored resin layer.

  The blending ratio of each component is 89.5 to 95.0 parts of polyethylene resin composition, 3.5 parts of polyethylene wax particles, 0 or 1.0 part of polyamide thixotropic agent, 1.5 parts of various pigments in terms of solid content. It mix | blended so that it might become ~ 6 parts (a dispersing agent included). The amount of the thixotropic agent and the pigment was changed so that the resin amount was changed and the total amount was 100 parts.

Experimental example 1
Each of the polyurethane-based and polyethylene-based colored resin layer forming resin compositions was adjusted to a solid content concentration of 10 to 18%, and stirred with a disper stirrer at 700 rpm for 10 minutes, and then the five types (EG1, EG2, GI, GL). , AL) is applied to the surface of the original plate with a roll coater, dried by heating at a plate temperature of 90 to 100 ° C., polyurethane has a thickness of 0.5 to 2.0 μm, and polyethylene has a thickness of 0.3 to 1.3 μm. A colored resin-coated metal plate on which a resin film was formed was obtained. The evaluation results are shown in Tables 3-18.

Experimental example 2
Of the resin composition for forming a polyurethane-based colored resin layer, 71.3 parts of a carboxyl group-containing polyurethane resin, 20 parts of colloidal silica, 2 parts of an epoxy-based crosslinking agent, 3.5 parts of polyethylene wax, 0.2 of a polyamide-based thixotropic agent Part and pigment 2 types (SA green DY-4: 2.1 parts, SA bluish purple # 800: 0.9 parts) were blended to a total of 3 parts to adjust the solid content concentration to 10-18%. The mixture was stirred with a disper stirrer at 700 rpm for 10 minutes.

  Separately, a paint for clear coating was prepared. An organic solvent-soluble polyester resin (Toyobo Co., Ltd .: Byron (registered trademark) 29) and a melamine cross-linking agent (Sumitomo Chemical Co., Ltd .: Sumimar (registered trademark) M-40ST, solid content 80%) were mixed in a mass ratio (dry ) After mixing at 100: 20 and diluting with xylene / cyclohexanone (mass ratio 1: 1) as a diluent solvent so that the solid content concentration becomes 5 to 20%, 5 at 3000 rpm with a disper stirrer. Stir for minutes.

  After the above polyurethane-based colored resin layer forming resin composition is applied to the surface of EG1 and GI original plate with a roll coater and heated and dried at a plate temperature of 90 to 100 ° C. to form a colored resin layer having a thickness of 1.2 μm The clear coating material was applied with a bar coater so as to have a film thickness of 0.3 to 5.3 μm, and baked for 60 seconds at an ultimate plate temperature of 220 ° C. to obtain a 2-coat colored resin-coated metal plate. The evaluation results of this 2-coat colored resin-coated metal plate are shown in Table 19.

Experimental example 3
Among the pigments shown in Table 2, SA Black DY-6 (black), GP White 13600 (white), SA Blue DY-12 (blue), SA Yellow RS (yellow), PSM Pink KR (red purple), SA For green DY-4 (green) and SA blue purple # 800 (blue purple), the polyurethane colored resin layer forming resin composition prepared in Preparation Example 1 and the polyethylene colored resin layer forming resin prepared in Preparation Example 2 A weather resistance test was conducted using the composition. The original plate, thixotropic agent concentration, pigment concentration, film thickness and the like were as shown in Table 20.
The weather resistance test is performed according to JIS K 5600 7-8, and the L value, a value, and b value before and after irradiating with a sunshine weather meter for 100 hours (without rain) are simultaneously measured by Nippon Denshoku Industries Co., Ltd. Measurement was performed with a photometric spectral color difference meter “SQ-2000”, and ΔE (color difference) was determined from the following equation.

  The case where ΔE was 2 or less was evaluated as ◯, and the case where it exceeded 2 was evaluated as Δ. The results are shown in Table 20.

  From Table 20, not only carbon black and titanium oxide, which are inorganic pigments, but also cyanine-based, quinacridone-based, and dioxazine-based organic pigments are excellent in weather resistance and have practically no problem. However, the disazo-based yellow pigment has a remarkable fading and is inferior in weather resistance. The determination that each pigment has faded can also be made by confirming an increase in the b value in blue, an increase in the a value in green, a decrease in the a value in red purple, and an increase in the b value in blue purple.

Experimental Example 4
The seven types of yellow pigments shown in Table 21 were subjected to a weather resistance test in the same manner as in Experimental Example 3. The original plate, thixotropic agent concentration, pigment concentration, film thickness and the like were as shown in Table 22. In the same manner as in Experimental Example 3, it was evaluated whether ΔE was 2 or less, and a change in b value representing a change in yellowness was also determined. In the comprehensive evaluation, both ΔE and b′-b were evaluated as ◯, and one of them as Δ was evaluated as △. The results are shown in Table 22.

  From the results shown in Table 22, it was confirmed that the three types of benzimidazolone, quinoxaline, and isoindolinone yellow pigments were excellent in weather resistance regardless of the types of the original plate, resin, and pigment dispersant. In addition, these three kinds of yellow pigments showed a unique property that the yellowness after the test increased and the yellowness of the resin coating film increased.

Experimental Example 5
In the same manner as in Experimental Example 1, the above seven types of yellow pigments were evaluated for whether or not the formulas (1) to (3) were satisfied, and the presence or absence of crater-like appearance defects. The results are shown in Tables 23 to 28.

  According to the present invention, it is possible to provide a colored resin-coated metal sheet having a high design property in which a metallic tone obtained by coloring a non-chromate original sheet with a thin film resin and a colored resin are combined at low cost. In addition, the colored resin-coated metal plate having a clear coating on the uppermost layer has excellent wear resistance and tape peel resistance.

  Therefore, the colored resin-coated metal plate of the present invention can be applied to various uses such as home appliances, building materials, and automobile parts.

Claims (8)

A non-chromate metal plate provided with a colored resin layer having a thickness of 0.3 to 2.2 μm on at least one surface, the colored resin layer containing one or more pigments and measured from the colored resin layer side When the 60 ° specular gloss is x and the average reflectance of 500 to 600 nm is y, the following expressions (1) and (2) are satisfied :
The colored resin layer contains one or more pigment dispersants selected from the group consisting of a water-soluble acrylic resin, a water-soluble styrene acrylic resin, and a nonionic surfactant,
The colored resin- coated metal plate , wherein the base resin of the colored resin layer is an aqueous polyurethane resin or an aqueous polyethylene resin .
(1) y ≧ −0.19x + 23.0
(2) y ≧ 10 The base resin for the colored resin layer is an aqueous polyurethane resin containing a carboxyl group or an olefin-α, β-unsaturated carboxylic acid copolymer, an α, β-unsaturated carboxylic acid polymer, and an aqueous solution containing an acrylic-modified epoxy resin. The colored resin-coated metal sheet according to claim 1, which is a polyethylene resin .   The colored resin-coated metal sheet according to claim 1 or 2, wherein the colored resin layer contains a polyamide thixotropic agent. Furthermore, the coloring resin coating metal plate of any one of Claims 1-3 which satisfy | fills following formula (3).
(3) y ≧ −0.27x + 41.3   The colored resin-coated metal sheet according to any one of claims 1 to 4, wherein the colored resin layer contains a yellow pigment, and the yellow pigment is any of benzimidazolone, quinoxaline, and isoindolinone.   The colored resin-coated metal plate according to any one of claims 1 to 5, wherein an average reflectance of 500 to 600 nm of the original plate before forming the colored resin layer is 50% or more.   The colored resin-coated metal sheet according to any one of claims 1 to 6, wherein a clear coating film is provided on the colored resin layer.   The colored resin-coated metal sheet according to claim 7, wherein the clear coating film has a thickness of 0.4 to 4.5 μm.