JP2012116057A - Chromate-free color-coated metal sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive chromium-free color-coated metal sheet which does not comprise hexavalent chromium having a high environmental load properties and has extremely superior designability (coloring properties and concealing properties including a worked part), moisture resistance, corrosion resistance, workability, scratch resistance, chemical resistance or the like.SOLUTION: The chromate-free color-coated metal sheet has a color-coating film (α) formed by coating at least one side of a metal sheet with an aqueous color composition (X) comprising the aqueous dispersion (A) of an organic resin (a) comprising an anionic functional group; the aqueous dispersion (B) of a color pigment (b2) dispersed by using a water-soluble acrylic resin (b1) as a dispersant; and the aqueous dispersion (C) of colloidal silica particles (c), and performing heating and drying.

Description

  The present invention relates to a chromate-free colored coated metal plate in which a colored coating film (α) not containing hexavalent chromium having high environmental impact is formed on at least one surface of the metal plate. The chromate-free colored coated metal plate of the present invention having such a structure is inexpensive and extremely excellent in designability (colorability including processing parts, concealment), moisture resistance, corrosion resistance, workability, scratch resistance, chemical resistance, etc. It is easy to make a chromate-free colored painted metal plate.

  For home appliances, building materials, and automobiles, pre-coated steel sheets coated with a colored organic film have been used in place of post-painted products that have been painted after conventional molding. This pre-coated steel sheet is coated with a colored organic film on a rust-proof steel sheet or plated steel sheet, and generally has good workability and good corrosion resistance while having beauty. It has the characteristic.

  For example, Patent Document 1 discloses a technique for obtaining a pre-coated steel sheet excellent in workability, stain resistance, and hardness by defining the structure of the film. On the other hand, Patent Document 2 discloses a precoated steel sheet having improved end face corrosion resistance by using a specific chromate treatment liquid. These pre-coated steel sheets have corrosion resistance, workability, and paint adhesion due to the combined effect of the plating film, chromate-treated film, and chrome-based anti-corrosive pigment (primary coating). The purpose is to improve productivity and quality.

  However, in view of the environmental load of hexavalent chromium that may be eluted from the chromate-treated film and the organic film containing the chromium-based anticorrosive pigment, recently there has been a growing demand for non-chromium anti-rust treatment and non-chromium organic film. . On the other hand, for example, Patent Document 3 and Patent Document 4 disclose non-chromium precoated steel sheets having excellent corrosion resistance, which have already been put into practical use.

  The coating used for these precoated steel sheets is thick with a coating film thickness of 10 μm or more. In addition, since a large amount of solvent-based paint is used, special coating equipment such as an incinerator and odor control equipment is required, and it is generally manufactured on a dedicated paint line. That is, since an extra coating process is passed in addition to the manufacturing process of the steel sheet as a coating original sheet, many costs are required in addition to the material cost required for coating. Therefore, the precoated steel sheet obtained is expensive.

  However, due to diversification of user needs, there is also a demand for colored steel sheets in fields where the purpose can be sufficiently achieved if it has durability under daily use conditions such as home appliances and interior building materials, and lower priced products are required. Yes. That is, conventional expensive pre-coated steel sheets alone are not sufficient to meet diversified demands.

  As a colored steel plate that can be manufactured at low cost for such needs, for example, a colored steel plate provided with a colored resin layer having a thickness of 5 μm or less in Patent Document 5 has a specific roughness in Patent Document 6. A colored steel sheet having a colored film on the surface is disclosed. However, these colored steel sheets are designed to ensure corrosion resistance by providing a chromate-treated film, and thus cannot meet the recent needs for non-chromation. In addition, since it has not been designed in consideration of the concealability of the processed and stretched colored layer, it has a problem that the appearance of the processed portion is remarkably deteriorated.

JP-A-8-168723 Japanese Patent Laid-Open No. 3-100180 JP 2000-199075 A JP 2000-262967 A Japanese Patent Laid-Open No. 5-16292 JP-A-2-93093

  An object of the present invention is to provide a chromate-free colored coated metal plate that does not contain hexavalent chromium having high environmental impact and can solve one or more of the problems described above in the prior art. Another object of the present invention is to provide a chromate-free colored coated metal sheet having design properties and excellent corrosion resistance and workability.

  As a result of diligent research, the present inventor contains an aqueous dispersion of a specific organic resin and an aqueous dispersion of a color pigment dispersed using a water-soluble acrylic resin in addition to an aqueous dispersion of colloidal silica particles. It has been found that the use of an aqueous coloring composition is extremely effective in achieving the above object.

  The chromate-free colored coated metal plate of the present invention is based on the above findings, and more specifically, an aqueous dispersion (A) of an organic resin (a) containing an anionic functional group; and a water-soluble acrylic resin as a dispersant An aqueous colored composition (X) containing an aqueous dispersion (B) of a colored pigment (b2) dispersed using (b1); and an aqueous dispersion (C) of colloidal silica particles (c), a metal It has a colored coating film (α) formed by applying to at least one side of a plate and drying by heating.

  In the present invention, the reason why the above effect is obtained is estimated as follows according to the knowledge of the present inventor.

  That is, as a method for ensuring the dispersibility of a good color pigment (carbon black or the like) in a water-based paint, a method of hydrophilizing the surface of the color pigment particles, a method of adding a surfactant when dispersing the color pigment Etc. However, in these methods, since the moisture resistance and corrosion resistance of the formed coating film are lowered, it is difficult to achieve both design properties, moisture resistance, and corrosion resistance.

  In addition, since the colored coated metal plate is used after being pressed, it is necessary to ensure high designability even at the site where the colored coating film is processed and the slide is subjected to sliding with a press die, It is important to design a colored coating film with a good balance of ductility, hardness and adhesion. In general, a coating film containing a coloring pigment has a film forming property that is deteriorated due to the influence of the coloring pigment, and it is difficult to ensure the above-described physical property balance. In addition, it is important to design colored coatings that take moisture resistance, corrosion resistance, workability, scratch resistance, chemical resistance, etc. into consideration so that the appearance of the design is not impaired by in-process rust or chemical cleaning until the product is finished. It is.

  The present inventor has intensively studied, an aqueous dispersion (A) of an organic resin (a) containing an anionic functional group, and a color pigment (b2) dispersed using a water-soluble acrylic resin (b1) as a dispersant. Chromate-free colored coated metal sheet having a colored coating film (α) using an aqueous coloring composition (X) containing an aqueous dispersion (B) of the above and an aqueous dispersion (C) of colloidal silica particles (c) As a result, the above object was achieved.

  According to the knowledge of the present inventors, in the chromate-free colored painted metal plate of the present invention having the above-described configuration, an aqueous dispersion of a colored pigment (b2) dispersed in advance using a water-soluble acrylic resin (b1) is used. By doing so, it is presumed that the dispersibility of the colored pigment is secured and stabilized even in the aqueous paint, and the above effect is obtained.

  This is due to the effect that the water-soluble acrylic resin (b1) adsorbs on the surface of the color pigment (b2) dispersed in advance using the water-soluble acrylic resin (b) so as to protect the color pigment (b2). In other words, this is due to the effect of preventing re-aggregation of the colored pigment (b2) once dispersed and the effect of reducing the interaction with other components in the aqueous paint and preventing aggregation with other components. In general, the water-soluble acrylic resin (b1) also has an effect of increasing the viscosity of the aqueous paint, and also has an effect of preventing sedimentation of the color pigment (b2) in the aqueous paint. Therefore, since it is not essential to add a surface hydrophilization treatment or a surfactant to enhance the dispersibility of the colored pigment (b2), there is a great concern that the moisture resistance and corrosion resistance of the formed colored coating film (α) may be lowered. small.

  Furthermore, in the chromate-free colored painted metal plate of the present invention having the above-described configuration, the color pigment (b2) is uniformly and finely dispersed in the coating film, so that the design property in the thin film (coloring including the processed portion) is achieved. It is presumed that security and concealment are guaranteed.

  The present invention can include, for example, the following modes [1] to [15].

[1] An aqueous dispersion (A) of an organic resin (a) containing an anionic functional group;
An aqueous coloring composition comprising an aqueous dispersion (B) of a color pigment (b2) dispersed using a water-soluble acrylic resin (b1) as a dispersant and an aqueous dispersion (C) of colloidal silica particles (c) A chromate-free colored coated metal sheet, comprising a colored coating film (α) formed by applying the product (X) to at least one surface of a metal sheet and drying by heating.

  [2] The chromate-free colored coated metal sheet according to [1], wherein the aqueous coloring composition (X) further contains a curing agent (D).

  [3] The color pigment (b2) contains carbon black (k), and the color coating film (α) has a thickness of 2 to 10 μm, [1] or [2] The chromate-free colored painted metal plate described in 1.

  [4] When the content of the carbon black (k) in the colored coating film (α) is Y mass% and the thickness of the colored coating film (α) is Z μm, Y × Z ≧ 20 and Y The chromate-free colored coated metal sheet according to [3], wherein ≦ 15 is satisfied.

  [5] The water-soluble acrylic resin (b1) solid content in the water dispersion (B) is 5 to 30% by mass with respect to 100% by mass of the carbon black (k) solid content. The chromate-free colored painted metal plate according to [3] or [4], which is characterized.

  [6] Any one of [3] to [5], wherein the carbon black (k) is dispersed in the colored coating film (α) with particles having a number average particle diameter of 20 to 300 nm. The chromate-free colored painted metal plate according to the item.

  [7] The chromate-free colored painted metal plate according to any one of [2] to [6], wherein the water-soluble acrylic resin (b1) contains a hydroxyl group in the structure.

  [8] The chromate-free material according to any one of [1] to [7], wherein the water-soluble acrylic resin (b1) contains a carboxyl group neutralized with an amine compound in the structure. Colored painted metal plate.

  [9] The chromate-free colored painted metal plate according to any one of [1] to [8], wherein the colloidal silica particles (c) are stabilized with an amine compound.

  [10] The organic resin (a) containing an anionic functional group contains at least one functional group selected from an ester group, a urethane group, and a urea group in the structure. [9] The chromate-free colored painted metal plate according to any one of [9].

  [11] The chromate-free painted metal plate according to [10], wherein at least a part of the anionic functional group is a sulfonic acid metal base.

  [12] The chromate-free painted metal sheet according to [10] or [11], wherein the organic resin (a) containing an anionic functional group further contains a bisphenol structure in the structure.

  [13] The chromate-free colored coated metal plate according to any one of [1] to [12], wherein the aqueous coloring composition (X) further contains a lubricant (E).

  [14] The chromate-free colored coated metal plate according to any one of [1] to [13], wherein a base treatment layer (β) is provided below the colored coating film (α).

  [15] An aqueous dispersion (A) of an organic resin (a) containing an anionic functional group, and an aqueous dispersion of a color pigment (b2) dispersed using a water-soluble acrylic resin (b1) as a dispersant ( An aqueous coloring composition (X) comprising B) and an aqueous dispersion (C) of colloidal silica particles (c).

  The chromate-free colored coated metal plate of the present invention is characterized in that it does not contain hexavalent chromium having high environmental impact, has design properties, and is excellent in corrosion resistance and workability.

  Furthermore, the chromate-free colored coated metal plate of the present invention having the above-described structure is inexpensive (low cost), has design properties (colorability including processing parts, concealment), moisture resistance, corrosion resistance, workability, and scratch resistance. It is extremely easy to obtain a colored coated metal plate having excellent chemical resistance. For this reason, it is very promising as an inexpensive high-design, high-value-added environment-friendly material, and the contribution to each industrial field is very large.

(Chromate-free colored metal plate) The colored coating (α) of the chromate-free colored metal plate of the present invention comprises an aqueous dispersion (A) of an organic resin (a) containing an anionic functional group and a water-soluble acrylic resin ( an aqueous dispersion (B) of the colored pigment (b2) dispersed using b1) and an aqueous dispersion (C) of colloidal silica particles, and containing an aqueous colored composition not containing chromium at least on the metal plate It is formed by applying to one side and drying by heating. The organic resin (a) itself is usually hydrophobic, but since the anionic functional group contained in the resin exhibits high hydrophilicity, the organic resin (a) containing the anionic functional group is stable in water. And can be dispersed.

  In addition, the organic resin (a) containing an anionic functional group improves the compatibility between water and a coloring pigment (b2) such as carbon black having a hydrophobic surface, and forms the coloring pigment (b2). It also has the effect of being stably and uniformly dispersed in the product. This is due to the effect obtained by orienting the hydrophobic organic resin (a) main structure to the color pigment (b2). That is, when the organic resin (a) is stably dissolved or dispersed in water, the color pigment (b2) can be uniformly dispersed as well. The expression of this excellent dispersibility is based on the fact that an anionic functional group exhibiting high hydrophilicity is contained in the hydrophobic organic resin (a).

  As described above, the colored coating film (α) formed from the aqueous composition in which the color pigment (b2) is uniformly and stably dispersed by the organic resin (a) containing an anionic functional group is also included in the coating film. The color pigment (b2) is uniformly dispersed and can exhibit excellent design properties (colorability and concealment) even in a thin film. In addition, the anionic functional group contained in the organic resin (a) has an effect of improving the adhesion to the metal plate as the base material (the base treatment layer when there is a base treatment), so that the obtained colored coating film (Α) is extremely excellent in adhesion to the substrate or the base treatment layer (β).

  That is, by using the organic resin (a) containing an anionic functional group together with the color pigment (b2) dispersed using the water-soluble acrylic resin (b1), the organic resin (a) is colored with a colored coating film (α ) As a binder component and the effect of enhancing the dispersibility of the colored pigment (b2), and also the addition of a surface hydrophilizing treatment and a surfactant to enhance the dispersibility of the colored pigment (b2) Since it is not essential, a balance between excellent design properties, moisture resistance, and corrosion resistance can be obtained.

  Further, an aqueous dispersion (A) of an organic resin (a) containing an anionic functional group and an aqueous dispersion (B) of a color pigment (b2) dispersed using a water-soluble acrylic resin (b1). The present invention is completed by adding an aqueous dispersion of colloidal silica particles to the water-based coloring composition contained in order to satisfy the properties other than the design required for the coated metal plate, in particular, corrosion resistance and scratch resistance. It came to do.

  Thus, the aqueous dispersion (A) of the organic resin (a) containing an anionic functional group and the aqueous dispersion (B) of the color pigment (b2) dispersed using the water-soluble acrylic resin (b1) And a colored coating film (α) formed by applying an aqueous coloring composition containing an aqueous dispersion of colloidal silica particles (C) to at least one surface of a metal plate and baking and drying it. Coloring, hiding properties), moisture resistance, corrosion resistance, workability, scratch resistance, chemical resistance, and the like.

(Water-based coloring composition)
In the present invention, the “aqueous dispersion” (or aqueous coloring composition) refers to a “dispersion” (or aqueous coloring composition) constituted using an aqueous solvent. Here, the “aqueous solvent” refers to a solvent containing water as a main component (50% by mass or more). By using an aqueous solvent, it is not necessary to pass an extra coating line for using an organic solvent-based paint, so that manufacturing costs can be greatly reduced and VOC emissions are also reduced. It also has environmental advantages such as significant suppression.

  If necessary, an organic solvent can be added to the “aqueous solvent”. However, from the viewpoint of occupational health, the “water dispersion” (or water-based coloring composition) of the present invention is an organic solvent-containing substance (Occupational Safety and Health Law) defined by the regulations on prevention of organic solvent poisoning in the Industrial Safety and Health Law. It is preferable that the organic solvent listed in Attached Table 6-2 of the Enforcement Ordinance does not fall under 5) by weight.

(Water-soluble resin)
The “water-soluble resin” that can be suitably used in the present invention refers to a resin having water solubility. More specifically, when an attempt was made to dissolve the polymer (resin) in water at a concentration of 1% by mass, efforts were made to homogenize by heating and stirring, and then left at 25 ° C. for 24 hours. Sometimes the solution is homogeneous without causing precipitation of the polymer and without phase separation.

(Colored coating film (α))
The colored coating film (α) preferably has a coating thickness of 2 to 10 μm. If the coating thickness is less than 2 μm, sufficient designability (colorability, concealment) and corrosion resistance may not be obtained. On the other hand, if the coating thickness is more than 10 μm, it is not only economically disadvantageous, but coating defects such as armpits may occur, and it is difficult to stably obtain the appearance necessary for industrial products. There is a tendency to increase.

  The thickness of the colored coating film (α) can be measured by observing the section of the coating film or using an electromagnetic film thickness meter. In addition, the mass of the coating film adhered per unit area may be calculated by dividing by the specific gravity of the coating film or the specific gravity after drying of the composition. The adhesion mass of the coating is the mass difference before and after coating, the mass difference before and after peeling the coating after coating, or the presence of an element whose content in the coating is known in advance by fluorescent X-ray analysis. What is necessary is just to select appropriately from existing methods, such as measuring quantity. The specific gravity of the coating film or the specific gravity after drying of the composition is measured by measuring the volume and mass of the isolated coating film, measuring the volume and mass after taking an appropriate amount of the composition in a container and drying it, or coating film. What is necessary is just to select suitably from the existing method, such as calculating from the compounding quantity of a structural component, and the known specific gravity of each component.

  Among the various measuring methods described above, since coatings having different specific gravities and the like can be easily and accurately measured, it is preferable to use cross-sectional observation of the coating.

  The method for observing the cross section of the colored coating film (α) is not particularly limited, but after embedding the coated metal plate perpendicularly to the thickness direction of the coating film in the room temperature drying type epoxy resin and mechanically polishing the embedded surface, SEM ( Using a scanning electron microscope) or a FIB (focused ion beam) device, a sample for observation having a thickness of 50 to 100 nm is cut out from the coated metal plate so that the vertical section of the coating can be seen, A method of observing with a TEM (transmission electron microscope) can be suitably used.

(Organic resin (a))
In the present invention, the organic resin (a) as the first component constituting the colored coating film (α) is an organic resin containing an anionic functional group.

(Anionic functional group)
In the present invention, the anionic functional group is not particularly limited. However, from the viewpoint of compatibility between the dispersion stability of the organic resin (a) and the color pigment (b2) and the water resistance and corrosion resistance of the colored coating film (α), An acid group and a carboxyl group can be preferably used. These functional groups may be neutralized with alkali metals, amines containing ammonia, or the like. When neutralizing, these already neutralized functional groups may be incorporated into the resin, or may be neutralized after these functional groups are incorporated into the resin.

  Among the above, sulfonic acid groups can be used particularly suitably from the viewpoints of dispersion stability of the color pigment (b2) and adhesion to the metal plate as the base material (the base treatment layer when there is a base treatment). In particular, a sulfonic acid metal base neutralized with an alkali metal such as Li, Na, or K is most preferable, and at least a part of the anionic functional group is preferably a sulfonic acid metal base.

(Type of organic resin (a))
In the present invention, the organic resin (a) is not particularly limited, and examples thereof include polyester resins, polyurethane resins, epoxy resins, acrylic resins, polyolefin resins, and modified products thereof. The organic resin (a) may be used alone or in combination of two or more, and an organic resin obtained by modifying at least one other organic resin in the presence of at least one organic resin. You may use 1 type or in mixture of 2 or more types.

  The organic resin (a) preferably contains at least one functional group selected from an ester group, a urethane group, and a urea group in the structure in order to achieve both workability and scratch resistance. In order to achieve both workability and scratch resistance, it is important to design a resin that is excellent in both elongation and strength, and that has excellent adhesion to the metal plate (base treatment layer if there is a base treatment). However, by introducing a functional group having a specific cohesive energy into the structure, it is possible to design a resin that is excellent in both elongation and strength and excellent in adhesion. In particular, when emphasizing processability, a resin containing an ester group with moderate cohesive energy is suitable in the structure, and when emphasizing scratch resistance, a urethane group or urea group having high cohesive energy is included in the structure. The resin it contains is preferred.

  In order to achieve both high workability and scratch resistance, a resin containing an ester group and a urethane group, or a resin containing an ester group, a urethane group, and a urea group is more preferable. The resin containing at least one functional group selected from an ester group, a urethane group, and a urea group in the structure is not particularly limited. For example, a polyester resin containing an ester group, a polyurethane resin containing a urethane group, and a urethane And a polyurethane resin containing both a group and a urea group. You may use these 1 type or in mixture of 2 or more types. For example, as a resin containing all ester groups, urethane groups, and urea groups, a polyester resin containing ester groups and a polyurethane resin containing both urethane groups and urea groups may be used.

  The organic resin (a) preferably further contains a bisphenol structure in the structure. Since the bisphenol structure has high cohesive energy and excellent water resistance, it is preferable to include the bisphenol structure in order to improve scratch resistance and corrosion resistance.

(Polyester resin)
There are no particular restrictions on the type of polyester resin that can be used in the present invention. For example, a polyester resin obtained by condensation polymerization of a polyester raw material comprising a polycarboxylic acid component and a polyol component can be obtained by dispersing in water Can be preferably used.

(Polycarboxylic acid component)
Examples of the polycarboxylic acid component include phthalic acid, phthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, methyltetraphthalic acid, methyltetrahydrophthalic anhydride, and hymic anhydride. , Trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, isophthalic acid, terephthalic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, succinic acid, One or a plurality of types such as succinic anhydride, lactic acid, dodecenyl succinic acid, dodecenyl succinic anhydride, cyclohexane-1,4-dicarboxylic acid, and anhydrous endo acid can be exemplified.

(Polyol component)
The polyol component is not particularly limited. For example, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,2-propanediol, triethylene glycol, 2-methyl-1,3-propanediol, 2,2 -Dimethyl-1,3-propanediol, 2-butyl-2-ethyl 1,3-propanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 2-methyl-3-methyl- 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1, 2-cyclohexanedimethanol, hydrogenated bisphenol-A, dimer diol, trimethylol eta , Trimethylolpropane, glycerol, pentaerythritol, and the like. These may be used alone or in combination of two or more.

(Sulfonic acid group)
The method for introducing a “sulfonic acid group” which is a suitable anionic functional group in the present invention is not particularly limited. For example, when the organic resin is a polyester resin, 5-sulfoisophthalic acid, 4-sulfonaphthalene- Dicarboxylic acids such as 2,7-dicarboxylic acid, 5 (4-sulfophenoxy) isophthalic acid, or 2-sulfo-1,4-butanediol, 2,5-dimethyl-3-sulfo-2,5-hexyldiol, etc. The method of using these glycols as a polyester raw material is mentioned.

  It is preferable that the usage-amount of the dicarboxylic acid or glycol containing a sulfonic acid group contains 0.1-10 mol% with respect to all the polycarboxylic acid components or all the polyol components. When the content is less than 0.1 mol%, the dispersibility in water decreases or the dispersibility of the color pigment (b2) decreases, and the design properties (colorability, concealment) of the colored coating film (α) in the thin film. May not be obtained. If it exceeds 10 mol%, the moisture resistance and corrosion resistance may decrease. From the viewpoint of the balance between the design properties (colorability and concealability), moisture resistance, and corrosion resistance in the thin film, it is more preferably in the range of 0.5 to 7 mol%.

The anionic functional group (for example, a sulfonic acid group represented by —SO ₃ H) contained in the organic resin (a) is neutralized with an alkali metal, an amine containing ammonia, or the like. It does not matter. When neutralizing, an anionic functional group that has already been neutralized may be incorporated into the resin, or may be neutralized after the anionic functional group is incorporated into the resin. In particular, sulfonic acid metal bases neutralized with alkali metals such as Li, Na, and K exhibit higher hydrophilicity, which is suitable for improving the dispersibility of the color pigment (b2) and obtaining high designability. is there. In addition, the anionic functional group is also an anionic functional group neutralized with an alkali metal (for example, a sulfonic acid metal base, particularly a sulfonic acid Na base) in order to improve the adhesion of the colored coating film (α) to the substrate. It is more preferable that

(Carboxyl group)
The method for introducing a “carboxyl group”, which is a suitable anionic functional group in the present invention, is not particularly limited. For example, when the organic resin is a polyester resin, the polyester resin is polymerized and then subjected to normal pressure and nitrogen atmosphere. Trimellitic anhydride, phthalic anhydride, pyromellitic anhydride, succinic anhydride, 1,8-naphthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, cyclohexane-1,2,3,4-tetracarboxylic acid -3,4-anhydride, ethylene glycol bisanhydro trimellitate, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, A method of selecting one or more from naphthalene-1,4,5,8-tetracarboxylic dianhydride, etc. Le put these acid anhydrides in those previous oligomeric state of high molecular weight, then a method in which a high molecular weight by polycondensation under reduced pressure, and the like.

  The carboxyl group refers to a functional group represented by —COOH, which may be neutralized with an alkali metal, an amine containing ammonia, or the like. When neutralizing, the already neutralized carboxyl group may be incorporated into the resin, or may be neutralized after the carboxyl group is incorporated into the resin.

  The amount of the carboxyl group introduced is not particularly limited, but the acid value is preferably in the range of 0.1 to 50 mgKOH / g. If it is less than 0.1 mg KOH / g, the effect of improving adhesion may not be obtained. Moreover, when using an aqueous solvent, the solubility or dispersibility with respect to water falls, and also when using a colored pigment, the dispersibility of a colored pigment may fall and the designability may fall. If it is 50 mgKOH / g, the corrosion resistance may decrease. Considering the balance of performance, it is more preferably in the range of 0.5 to 25 mgKOH / g.

(Bisphenol structure)
The method for introducing the bisphenol structure is not particularly limited. For example, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, an ethylene oxide adduct of bisphenol F, a propylene oxide adduct of bisphenol F The method of using glycols, such as these, as a polyester raw material is mentioned.

  It is preferable that the usage-amount of the glycol containing the said bisphenol structure contains 1-40 mol% with respect to all the polyol components. If it is less than 1 mol%, the effect of improving scratch resistance and corrosion resistance may not be obtained. If it exceeds 40 mol%, the processability may deteriorate. Considering the balance of performance, it is more preferably in the range of 5 to 30 mol%.

(Polyurethane resin)
The type of polyurethane resin that can be used in the present invention is not particularly limited, and examples thereof include those obtained by reacting a polyol compound with a polyisocyanate compound and then further extending the chain with a chain extender. .

  The polyol compound is not particularly limited as long as it is a compound containing two or more hydroxy groups per molecule. For example, polycarbonate polyol, polyester polyol, polyether polyol, polyesteramide polyol, acrylic polyol, polyurethane polyol, or A mixture thereof may be mentioned. These compounds can be used alone or in a mixture of two or more.

  The polyisocyanate compound is not particularly limited as long as it is a compound containing two or more isocyanate groups per molecule. For example, aliphatic isocyanate, alicyclic diisocyanate, aromatic diisocyanate, araliphatic diisocyanate, or those Of the mixture. The chain extender is not particularly limited as long as it is a compound containing one or more active hydrogens in the molecule, and ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepenta. Aliphatic polyamines such as min, aromatic polyamines such as tolylenediamine, xylylenediamine, diaminodiphenylmethane, alicyclic polyamines such as diaminocyclohexylmethane, piperazine, 2,5-dimethylpiperazine, isophoronediamine, hydrazine, Hydrazines such as succinic acid dihydrazide, adipic acid dihydrazide, phthalic acid dihydrazide, hydroxyethyldiethylenetriamine, 2-[(2-aminoethyl) amino] ethanol, 3-aminopropane Alkanolamines such as ol. These compounds can be used alone or in a mixture of two or more.

(Colored pigment aqueous dispersion (B))
The 2nd component which comprises a colored coating film ((alpha)) is the water dispersion (B) of a color pigment. The aqueous dispersion (B) of the color pigment is an aqueous dispersion of the color pigment (b2) dispersed using the water-soluble acrylic resin (b1) as a dispersant. By containing such an aqueous dispersion of the colored pigment (b2), the dispersibility of the colored pigment (b2) in the aqueous colored composition for forming the colored coating film (α) can be further improved, The designability (colorability and concealment) in the thin film can be further enhanced.

  The colored pigment (b2) is not particularly limited, and examples thereof include colored inorganic pigments such as titanium dioxide, carbon black, graphite, iron oxide, lead oxide, coal dust, talc, cadmium yellow, cadmium red, and chrome yellow; phthalocyanine Blue, Phthalocyanine Green, Quinacridone, Perylene, Anthrapyrimidine, Carbazole Violet, Anthrapyridine, Azo Orange, Flavanthrone Yellow, Isoindoline Yellow, Azo Yellow, Indanthrone Blue, Dibromoanthanthrone Red, Perylene Red, Azo Red, Anthraquinone Red, Colored organic pigments such as: aluminum powder, alumina powder, bronze powder, copper powder, tin powder, zinc powder, iron phosphide, metal-coated mica powder, titanium dioxide-coated mica powder, diacid It can be mentioned luminous material such as titanium-coated glass powder.

  When the colored coating film (α) is colored in a deep color or when an excellent design property is imparted with a thin film having a film thickness of 10 μm or less, the colored pigment (b2) contains carbon black (k). It is preferable to do.

  The type of the carbon black (k) is not particularly limited, and known carbon blacks such as furnace black, ketjen black, acetylene black, channel black and the like can be used. Further, carbon black subjected to known ozone treatment, plasma treatment, or liquid phase oxidation treatment can also be used. The particle size of the carbon black to be used is not particularly limited as long as there is no problem in dispersibility, coating film quality, and paintability in the composition. Specifically, a carbon black having a primary particle size of 10 to 120 nm may be used. Is possible. In consideration of design properties (colorability, concealability) and corrosion resistance in a thin film, it is preferable to use fine carbon black having a primary particle diameter of 10 to 50 nm. Since these carbon blacks aggregate in the process of dispersion in the composition, it is generally difficult to disperse with the primary particle size. That is, actually, it exists in the composition in the form of secondary particles having a particle diameter larger than the primary particle diameter, and also exists in the same form in the colored coating film (α) formed from the composition. In order to ensure designability (colorability, concealability) and corrosion resistance in a thin film, the particle size of the carbon black (k) dispersed in the coating film is important, and the number average particle size is 20 to 300 nm. It is preferable that it exists in. The particle size of such carbon black (k) can be suitably measured using a FIB (focused ion beam) apparatus, as will be described later in Examples.

  When the content of the carbon black (k) in the colored coating film (α) is X mass% and the thickness of the colored coating film (α) is Y μm, X × Y ≧ 20 and X ≦ 15. It is preferable to satisfy. In order to ensure designability (colorability and concealment), it is also important to secure a certain amount or more of the absolute amount of carbon black contained in the colored coating film (α). The absolute amount of carbon black can be represented by the product of the carbon black content (X mass%) contained in the coating film and the coating film thickness (Y μm). That is, if X × Y is less than 20, design properties (colorability and concealment) may be deteriorated. Moreover, when X is more than 15, the film-forming property of the coating film is lowered, and the corrosion resistance and workability may be lowered.

  When the colored coating film (α) is colored lightly, it is preferable that the colored pigment (b2) contains titanium dioxide. It is preferable that content in the said coating film ((alpha)) of the said titanium dioxide is 5-50 mass%. If it is less than 5% by mass, the designability (concealment) may be reduced, and if it exceeds 50% by mass, the workability and corrosion resistance may be reduced. Generally, when the coating film (α) contains the carbon black (k) and is colored deeply, it is more scratched than when it is not colored or lightly colored. It has the feature that it is easily noticeable when. The titanium dioxide has the effect of raising the scratch resistance, and also has the effect of making the appearance close to light and making the scratches less noticeable. Therefore, in order to improve the scratch resistance while ensuring designability (concealment), workability, and corrosion resistance when coloring with a thin film having a film thickness of 10 μm or less, the carbon film in the colored coating film (α) is improved. It is preferable to contain both black (k) and the titanium dioxide. In this case, the carbon black (k) and the titanium dioxide are preferably contained in a mass ratio of 9.5 / 0.5 to 7/3.

(Water-soluble acrylic resin (b1)) If the kind of acrylic resin used as a dispersing agent in this invention is water-soluble, there will be no restriction | limiting in particular. Examples of resins that can be used in the present invention include those obtained by radical polymerization of monomers in an aqueous solution using a polymerization initiator.

  Examples of the monomers include ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, maleic acid and itaconic acid; (meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylic Ethylenically unsaturated carboxylic acid alkyl ester monomers such as n-butyl acid and (meth) acrylic acid-2-ethylhexyl; ethylenically unsaturated dicarboxylic acids such as ethyl maleate, butyl maleate, ethyl itaconate and butyl itaconate Monoester monomer of acid; (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid-4-hydroxybutyl, (meth) acrylic acid-2-hydroxy Ethylenic unsaturated compounds containing hydroxyl groups such as the reaction product of ethyl and ε-caprolactone Carboxylic acid alkyl ester monomers; (Meth) aminoethyl acrylate, (Meth) dimethylaminoethyl acrylate, (Meth) butylaminoethyl acrylate and other ethylenically unsaturated carboxylic acid aminoalkyl ester monomers; Ethylene unsaturated carboxylic acid aminoalkylamide monomers such as (meth) acrylamide, dimethylaminomethyl (meth) acrylamide, methylaminopropyl (meth) acrylamide; acrylamide, methacrylamide, N-methylolacrylamide, methoxybutylacrylamide, di Other amide group-containing ethylenically unsaturated carboxylic acid monomers such as acetone acrylamide; Unsaturated fatty acid glycidyl ester monomers such as glycidyl acrylate and glycidyl methacrylate; Examples thereof include “acrylic monomers” such as vinyl cyanide monomers such as acrylonitrile and α-chloroacrylonitrile. These “acrylic monomers” may be those using the above monomers alone or in combination of two or more components.

  As the “acrylic monomer”, if necessary, another monomer copolymerizable with the monomer may be copolymerized with the “acrylic monomer”. Examples of such “other monomers” include saturated aliphatic carboxylic acid vinyl ester monomers such as vinyl acetate and vinyl propionate; styrene monomers such as styrene, α-methylstyrene and vinyltoluene; These vinyl monomers can be preferably used. These “other monomers” may be used alone or in combination of two or more components. In the present invention, when the copolymer is used as “water-soluble acrylic resin (b1)”, the amount of “other monomer” used is 100 parts by mass of “acrylic monomer”. It is preferably 300 parts by mass or less, and more preferably 20 to 200 parts by mass.

(Polymerization initiator)
The polymerization initiator is not particularly limited, and for example, persulfates such as potassium persulfate and ammonium persulfate, and azo compounds such as azobiscyanovaleric acid and azobisisobutyronitrile can be used. The acrylic monomer mixture having an ethylenically unsaturated double bond may be one that uses the monomer alone or may be one that uses two or more components in combination.

(Hydroxyl group)
When the aqueous coloring composition (X) of the present invention further contains a curing agent (D) described later, the water-soluble acrylic resin (b1) preferably contains a hydroxyl group in the structure. Since the acrylic resin (b1) is water-soluble, if it is contained as it is in the coating film, the water resistance and corrosion resistance may be lowered. By including a hydroxyl group in the structure, it becomes a starting point for crosslinking with the curing agent, and is taken into the coating film as a crosslinked body via the curing agent, so that water resistance and corrosion resistance can be greatly improved. The method for introducing a hydroxyl group into the structure of the water-soluble acrylic resin (b1) is not particularly limited. For example, an acrylic monomer (and / or “other monomer” to be copolymerized) is copolymerized if necessary. A method of using an acrylic monomer containing a hydroxyl group as a part of the acrylic monomer when polymerizing an acrylic resin by polymerization.

  The introduction amount of the hydroxyl group is not particularly limited, but the hydroxyl value is preferably in the range of 30 to 150 mgKOH / g. Considering the balance of performance, it is more preferably in the range of 50-100.

(Carboxyl group)
The acrylic resin (b1) preferably contains a carboxyl group neutralized with an amine compound in the structure. The amine compound is not particularly limited, and examples thereof include tertiary amines such as ammonia and trimethylamine, triethylamine, diethanolamine, triethanolamine, triisopropanolamine, and dimethylethanolamine. Since the carboxyl group is excellent in hydrophilicity, the affinity with water as the main component of the solvent can be increased, and the dispersibility of the colored pigment (b2) can be increased. Furthermore, neutralization of the carboxyl group with an amine compound can further increase the hydrophilicity, and the dispersibility of the colored pigment (b2) can be further increased. Examples of basic substances that neutralize carboxyl groups include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, and calcium hydroxide in addition to amine compounds. This is not preferable because it may remain in the colored coating film and may reduce water resistance and corrosion resistance.

  The amount of the carboxyl group introduced is not particularly limited, but the acid value is preferably in the range of 0.1 to 50 mgKOH / g. If it is less than 0.1 mg KOH / g, the effect of improving adhesion may not be obtained. Moreover, when using an aqueous solvent, the solubility or dispersibility with respect to water falls, and also when using a colored pigment, the dispersibility of a colored pigment may fall and the designability may fall. If it exceeds 50 mgKOH / g, the corrosion resistance may decrease. Considering the balance of performance, it is more preferably in the range of 0.5 to 25 mgKOH / g.

(Solid content)
It is preferable that content of the said water-soluble acrylic resin (b2) solid content in the said water dispersion (B) is 5-30 mass% with respect to 100 mass% of solid content of the said color pigment (b2). If it is less than 5% by mass, the dispersion stability of the color pigment (b2) may be lowered, and the designability (colorability and concealing property) may be lowered. If it exceeds 30% by mass, corrosion resistance and workability may deteriorate. When the color pigment (b2) contains carbon black (k), it is more preferably 15 to 30% by mass.

(Colloidal silica aqueous dispersion (C))
The 3rd component which comprises a colored coating film ((alpha)) is the water dispersion (C) of colloidal silica particle (c). By including such an aqueous dispersion (C) of colloidal silica, corrosion resistance and scratch resistance are improved. Although it does not restrict | limit especially as an aqueous dispersion (C) of colloidal silica, It is preferable that it is a colloidal silica fine particle with a primary particle diameter of 5-50 nm. Examples of commercially available products include Snowtex O, Snowtex N, Snowtex C, Snowtex IPA-ST (Nissan Chemical Industry), Adelite AT-20N, AT-20A (Asahi Denka Kogyo) and the like. It is preferable from the viewpoint of corrosion resistance and workability that these colloidal silica particles are dispersed in the colored coating film (α) while maintaining the primary particle diameter (average particle diameter) of 5 to 50 nm.

  The primary particle diameter of the colloidal silica particles (c) can be measured by a dynamic light scattering method (nanotrack method). According to the dynamic scattering method, the diameter of fine particles in a dispersion medium having a known temperature, viscosity, and refractive index can be easily obtained.

  The particulate component used in the present invention is selected so that it does not significantly dissolve in the aqueous solvent of the paint and does not react with the solvent or other coating film components. It can be employed as the particle size of the particulate component in the dispersion. In the dynamic light scattering method, laser light is irradiated to fine particles that are dispersed in a dispersion medium and moving in brown, the scattered light from the particles is observed, the autocorrelation function is obtained by the photon correlation method, and the cumulant method is used. Measure the particle size.

  As a particle size measuring device by the dynamic light scattering method, for example, FPAR-1000 manufactured by Otsuka Electronics Co., Ltd. can be used. In the present invention, a dispersion sample containing the particles to be measured is measured at 25 ° C. to determine the cumulant average particle size, and the average value of five measurements in total is taken as the average particle size of the particles. The measurement of the average particle diameter by the dynamic light scattering method is described in, for example, Journal of Chemical Physics, Vol. 57, No. 11 (December, 1972), page 4814.

  The colloidal silica particles (C) are preferably stabilized with an amine compound. The amine compound is not particularly limited, and examples thereof include tertiary amines such as ammonia and trimethylamine, triethylamine, diethanolamine, triethanolamine, triisopropanolamine, and dimethylethanolamine. Examples of commercially available products include Snowtex N (Nissan Chemical Industries) and Adelite AT-20A (Asahi Denka Kogyo). When the colloidal silica particles (C) are stabilized with an amine compound, the stability of the acrylic resin (b1), which is a dispersant for the colored pigment (b2), can be increased, Since the dispersibility of a color pigment (b2) can be improved, it is preferable.

  The content of the colloidal silica aqueous dispersion (C) is preferably 5 to 30% by mass in the colored coating film (α). If it is less than 5% by mass, the corrosion resistance and scratch resistance may be reduced, and if it exceeds 30% by mass, the moisture resistance, corrosion resistance, and workability may be reduced.

(Curing agent (D))
In the present invention, it is preferable to use a curing agent (D). Such a curing agent (D) is not particularly limited as long as it cures the organic resin (a), and examples thereof include a melamine resin, a polyisocyanate compound, and an epoxy compound. The melamine resin is a resin obtained by etherifying a part or all of the methylol group of a product obtained by condensing melamine and formaldehyde with a lower alcohol such as methanol, ethanol, or butanol. It does not specifically limit as a polyisocyanate compound, For example, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate etc. can be mentioned. Examples of the blocked product include a blocked product of hexamethylene diisocyanate, a blocked product of isophorone diisocyanate, a blocked product of xylylene diisocyanate, and a blocked product of tolylene diisocyanate, which are blocked products of the polyisocyanate compound. These curing agents may be used alone or in combination of two or more.

  Content of the said hardening | curing agent (D) points out all organic resins (when the said colored coating film ((alpha)) contains organic resins other than the said organic resin (a), including all the organic resins. However, the lubricant (E) described later is not included.) It is preferably 5 to 35% by mass with respect to 100% by mass. If it is less than 5% by mass, the bake-curing may be insufficient, and the moisture resistance, corrosion resistance, scratch resistance, and chemical resistance may decrease. If it exceeds 35% by mass, the bake-curing will be excessive and the corrosion resistance will be reduced. , Workability may be reduced.

  From the viewpoint of scratch resistance and chemical resistance, the curing agent (D) preferably contains a melamine resin. It is preferable that content of a melamine resin is 30-100 mass% in the said hardening | curing agent (D). If it is less than 30% by mass, scratch resistance and chemical resistance may deteriorate.

(Lubricant (E))
The colored coating film (α) preferably further contains a lubricant (E). By including the lubricant (E), the scratch resistance is improved. The lubricant (E) is not particularly limited, and a known lubricant can be used, but it is preferable to use at least one selected from a fluororesin system and a polyolefin resin system.

(Fluorine resin)
Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polychlorotrifluoroethylene (PCTFE). ), Polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and the like can be used. Of these, one type may be used alone, or two or more types may be used in combination.

(Polyolefin resin)
The polyolefin resin system is not particularly limited, and examples thereof include hydrocarbon waxes such as paraffin, microcrystalline, and polyethylene, and derivatives thereof, but a polyethylene resin is preferable. The derivative is not particularly limited, and examples thereof include carboxylated polyolefin and chlorinated polyolefin. Of these, one type may be used alone, or two or more types may be used in combination. When using the said polyethylene resin, it is preferable from a viewpoint of corrosion resistance or damage resistance that it is disperse | distributed by the particle | grains with an average particle diameter of 0.5-2 micrometers in the said colored coating film ((alpha)).

  The average particle diameter of the polyethylene resin particles refers to a particle diameter at an integrated value of 50% in a particle size distribution measured by a laser diffraction / scattering method (microtrack method). For the measurement by the laser diffraction / scattering method, for example, it can be measured by a microtrack particle size analyzer manufactured by Nikkiso Co., Ltd. In this invention, let the average value of a total of 5 measurements be the average particle diameter of the said polyethylene resin particle.

  The content of the lubricant (E) is preferably 0.5 to 10% by mass in the colored coating film (α). If it is less than 0.5% by mass, the scratch resistance may be lowered, and if it exceeds 10% by mass, the corrosion resistance and workability may be lowered.

(Colored coating film (α))
The colored coating (α) of the chromate-free colored coated metal plate of the present invention uses an aqueous dispersion (A) of an organic resin (a) containing an anionic functional group and a water-soluble acrylic resin (b1) as a dispersant. An aqueous coloring composition (X) containing an aqueous dispersion (B) of the colored pigment (b2) dispersed in water and an aqueous dispersion (C) of colloidal silica particles (c) is applied to at least one surface of the metal plate. It can be formed by baking and drying. Although there is no restriction | limiting in particular in the coating method of the said aqueous coloring composition, Well-known roll coat, curtain coating, spray coating, bar coating, immersion, electrostatic coating etc. can be used suitably.

(Aqueous coloring composition)
Although the manufacturing method of the said aqueous coloring composition (X) is not specifically limited, For example, the method of adding each coloring coating film ((alpha)) formation component in water, stirring with a disper, and melt | dissolving or disperse | distributing is mentioned. In order to improve the solubility or dispersibility of each colored coating film (α) forming component, a known hydrophilic solvent or the like may be added as necessary.

  The pH of the aqueous coloring composition (X) at 25 ° C. is preferably in the range of 8 to 10, and more preferably in the range of 8.5 to 9.5. If the pH is less than 8, the storage stability of the aqueous coloring composition (X) may be reduced (thickening or gelation occurs), or the dispersion stability of the colored pigment (b2) may be reduced. If the pH is higher than 10, water resistance, corrosion resistance, and chemical resistance may decrease. Although there is no restriction | limiting in particular in the control method of pH of the said aqueous coloring composition (X), The method etc. which add and adjust amine compounds, such as organic acids, such as acetic acid, and ammonia, etc. are mentioned.

(Heat drying method)
The heating (or baking) drying method is not particularly limited, and the metal plate may be heated in advance, the metal plate may be heated after application, or a combination thereof may be used for drying. There is no restriction | limiting in particular in a heating method, A hot air, induction heating, near infrared rays, a direct fire, etc. can be used individually or in combination. The baking drying temperature is preferably 150 ° C. to 250 ° C., more preferably 160 ° C. to 230 ° C., and most preferably 180 ° C. to 220 ° C. at the ultimate temperature. If the ultimate temperature is less than 150 ° C., the bake hardening is insufficient, and the moisture resistance, corrosion resistance, scratch resistance, and chemical resistance may decrease. If it exceeds 250 ° C., the bake hardening will be excessive. Corrosion resistance and workability may decrease. The baking and drying time is preferably 1 to 60 seconds, and more preferably 3 to 20 seconds. If it is less than 1 second, the bake hardening is insufficient, and the moisture resistance, corrosion resistance, scratch resistance, and chemical resistance may decrease, and if it exceeds 60 seconds, the productivity may decrease.

(Base treatment layer (β))
In the present invention, from the viewpoint that the adhesion between the colored coating film (α) and the base metal plate can be improved or the corrosion resistance can be improved, a base treatment layer ( β) is preferably arranged. Although the said base treatment layer ((beta)) is not specifically limited, By providing the base treatment layer ((beta)) containing at least 1 sort (s) chosen from a silane coupling agent, organic resin, and a polyphenol compound, a base metal plate and The adhesion can be further improved, and the corrosion resistance can be further improved. Moreover, by providing the base treatment layer (β) containing all of the silane coupling agent, the organic resin, and the polyphenol compound, the adhesion with the base metal plate can be maximized and the corrosion resistance can be enhanced most.

(Silane coupling agent)
The silane coupling agent that can be contained in the base coating layer (β) is not particularly limited, and examples thereof include vinyltrimethoxysilane and vinyltril sold by Shin-Etsu Chemical, Nippon Unicar, Chisso, Toshiba Silicone and the like. Ethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylethoxysilane, N- [2- (vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ- Methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycyl Sidoxypropyl Methoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and the like can be mentioned. The said silane coupling agent may be used independently and may use 2 or more types together.

(Organic resin for the ground treatment layer (β))
The organic resin that can be included in the base treatment layer (β) is not particularly limited. For example, a known organic resin such as a polyester resin, a polyurethane resin, an epoxy resin, a phenol resin, an acrylic resin, or a polyolefin resin can be used. . In order to further improve the adhesion to the base metal plate, it is preferable to use at least one of a polyester resin, a polyurethane resin, an epoxy resin, and a phenol resin, and the polyester resin contained in the colored coating film (α) It is particularly preferable to contain a polyester resin in the base treatment layer (β) in the sense of enhancing the compatibility with the base material.

(Polyphenol compound)
The polyphenol compound that can be contained in the base treatment layer (β) refers to a compound having two or more phenolic hydroxyl groups bonded to a benzene ring, or a condensate thereof. Examples of the compound having two or more phenolic hydroxyl groups bonded to the benzene ring include gallic acid, pyrogallol, catechol and the like. The condensate of the compound having two or more phenolic hydroxyl groups bonded to the benzene ring is not particularly limited, and examples thereof include polyphenol compounds that are widely distributed in the plant kingdom, usually called tannic acid.

(Tannic acid)
Tannic acid is a general term for aromatic compounds having a complex structure having a large number of phenolic hydroxyl groups widely distributed in the plant kingdom. The tannic acid may be hydrolyzable tannic acid or condensed tannic acid. The tannic acid is not particularly limited, and examples thereof include hameli tannin, oyster tannin, chatannin, pentaploid tannin, gallic tannin, mylobarantannin, dibidi tannin, algarobilatannin, valonia tannin, catechin tannin, and the like. . Examples of the tannic acid include commercially available ones such as “tannic acid extract A”, “B tannic acid”, “N tannic acid”, “industrial tannic acid”, “purified tannic acid”, “Hi tannic acid”, "F tannic acid", "local tannic acid" (all manufactured by Dainippon Pharmaceutical Co., Ltd.), "tannic acid: AL" (manufactured by Fuji Chemical Industry Co., Ltd.) and the like can also be used.

  The said polyphenol compound may be used by 1 type, and may use 2 or more types together.

(Content)
Although content of at least 1 sort (s) chosen from the silane coupling agent, organic resin, and polyphenol compound contained in the said base treatment layer ((beta)) is not specifically limited, It contains 10 mass% or more in 100 mass% of base treatment layers. Is preferred. If it is less than 10% by mass, the content may be small and the effect of improving adhesion and corrosion resistance may not be obtained.

(Amount of adhesion)
Although the adhesion amount of the said base treatment layer ((beta)) is not specifically limited, It is preferable to exist in the range of 10-1000 mg / m < ² >. When the amount is 10 mg / m ² or less, sufficient effect of the base treatment layer (β) cannot be obtained, and when it exceeds 1000 mg / m ² , the base treatment layer (β) tends to cohesively break down and adhesion may be lowered. From the stable effect and economical efficiency, a more preferable adhesion amount range is 50 to 500 mg / m ² .

(Formation method)
Although there is no restriction | limiting in particular in the formation method of the said base treatment layer ((beta)), The coating agent for forming a base treatment layer ((beta)) is apply | coated to at least one side of a metal plate, and it heat-drys and forms. Although there is no restriction | limiting in particular in the coating method of the said coating agent, Well-known roll coat, spray coating, bar coating, immersion, electrostatic coating etc. can be used suitably. There is no restriction | limiting in particular in the baking drying method, A metal plate may be heated previously, a metal plate may be heated after application | coating, or you may dry combining these. There is no restriction | limiting in particular in a heating method, A hot air, induction heating, near infrared rays, a direct fire, etc. can be used individually or in combination. About baking baking temperature, it is preferable that it is 60 to 150 degreeC by the ultimate temperature, and it is still more preferable that it is 70 to 130 degreeC. If the ultimate temperature is less than 60 ° C., drying may be insufficient, and adhesion and corrosion resistance with the substrate may decrease, and if it exceeds 150 ° C., adhesion with the substrate may decrease. .

(Metal plate)
The metal plate applicable in the present invention is not particularly limited, and examples thereof include iron, iron-base alloy, aluminum, aluminum-base alloy, copper, copper-base alloy, and the like, and optionally plated on the metal plate. A plated metal plate can also be used. Among them, the most preferable ones in the application of the present invention are zinc-based plated steel sheets and aluminum-based plated steel sheets.

  Zinc-coated steel sheets include galvanized steel sheets, zinc-nickel plated steel sheets, zinc-iron plated steel sheets, zinc-chromium plated steel sheets, zinc-aluminum plated steel sheets, zinc-titanium plated steel sheets, zinc-magnesium plated steel sheets, zinc-manganese. Galvanized steel sheets such as plated steel sheets, zinc-aluminum-magnesium plated steel sheets, zinc-aluminum-magnesium-silicon-plated steel sheets, and cobalt, molybdenum, tungsten, nickel as a small amount of different metal elements or impurities in these plated layers Examples include those containing titanium, chromium, aluminum, manganese, iron, magnesium, lead, bismuth, antimony, tin, copper, cadmium, arsenic, and the like, and those in which inorganic substances such as silica, alumina, and titania are dispersed.

  Examples of the aluminum-based plated steel sheet include aluminum or an alloy composed of aluminum and at least one of silicon, zinc, and magnesium, such as an aluminum-silicon plated steel sheet, an aluminum-zinc plated steel sheet, and an aluminum-silicon-magnesium plated steel sheet. .

  Furthermore, the present invention can also be applied to multilayer plating in combination with the above plating and other types of plating such as iron plating, iron-phosphorus plating, nickel plating, cobalt plating and the like. The plating method is not particularly limited, and any known method such as an electroplating method, a hot dipping method, a vapor deposition plating method, a dispersion plating method, and a vacuum plating method may be used.

  Examples of the present invention will be described below. However, the present invention is not limited to these examples. In the examples, “parts” means “parts by mass” unless otherwise specified.

(1) Metal plate Table 1 shows the types of metal plates used. A mild steel plate having a thickness of 0.5 mm was used as the base material of the plated metal plate. For SUS plate, ferritic stainless steel plate (steel component: C; 0.008 mass%, Si; 0.07 mass%, Mn; 0.15 mass%, P; 0.011 mass%, S; 0.009 mass) %, Al; 0.067% by mass, Cr; 17.3% by mass, Mo; 1.51% by mass, N; 0.0051% by mass, Ti; 0.22% by mass, balance Fe and inevitable impurities) used. The metal plate was used after subjecting the surface to alkaline degreasing treatment, washing with water and drying.

(2) Ground treatment layer The coating agent for forming the ground treatment layer is composed of an organic resin (Table 2), a silane coupling agent (Table 3), and a polyphenol compound (Table 4) in the blending amounts shown in Table 5. It was adjusted by stirring using a paint disperser. The coating agent is applied to the surface of the metal plate prepared in (1) above with a roll coater so as to have an adhesion amount of 100 mg / m ² , and dried under the condition of a reaching plate temperature of 70 ° C. A ground treatment layer was formed.

(3) Water-soluble acrylic resin Production examples of a water-soluble acrylic resin used as a dispersant for the color pigment (b2) are shown in the following Production Examples 1 to 3 and Table 6.
<Water-soluble acrylic resin production example 1>
40.0 parts of dipropylene glycol methyl ether was added to the reaction vessel, and the temperature was raised to 120 ° C. while mixing and stirring in a nitrogen stream. Next, a monomer mixture comprising 8.5 parts of methacrylic acid, 54.5 parts of ethyl acrylate, 14.5 parts of 2-hydroxyethyl acrylate, 12.5 parts of methyl methacrylate, 10.0 parts of styrene, and dipropylene An initiator solution consisting of 10.0 parts of glycol methyl ether and 5 parts of tertiary butyl peroxy-2-ethylhexanoate was dropped into the reaction vessel in parallel over 3 hours.

  After completion of the dropping, aging was performed at the same temperature for 0.5 hours. Further, an initiator solution consisting of 5.0 parts of dipropylene glycol methyl ether and 0.3 part of tert-butyl peroxy-2-ethylhexanoate was added dropwise to the reaction vessel over 0.5 hours. After completion of the dropping, aging was performed at the same temperature for 2 hours. After removing 11.11 parts of the solvent at 120 ° C. under reduced pressure (9.3 kPa (70 torr)) using a solvent removal apparatus, 194.24 parts of deionized water and 8.82 parts of dimethylaminoethanol were added to obtain a nonvolatile content. An acrylic resin aqueous solution containing 30.0% of a carboxyl group and a hydroxyl group neutralized with an amine compound was obtained.

<Water-soluble acrylic resin production example 2>
40.0 parts of dipropylene glycol methyl ether was added to the reaction vessel, and the temperature was raised to 120 ° C. while mixing and stirring in a nitrogen stream. Next, a monomer mixture comprising 8.5 parts of methacrylic acid, 69.0 parts of ethyl acrylate, 12.5 parts of methyl methacrylate, 10.0 parts of styrene, 10.0 parts of dipropylene glycol methyl ether, and tertiary butyl par An initiator solution consisting of 5 parts of oxy-2-ethylhexanoate was added dropwise to the reaction vessel in parallel over 3 hours. After completion of the dropping, aging was performed at the same temperature for 0.5 hours. Further, an initiator solution consisting of 5.0 parts of dipropylene glycol methyl ether and 0.3 part of tertiary butyl peroxy-2-ethylhexanoate was added dropwise to the reaction vessel over 0.5 hours.

  After completion of the dropping, aging was performed at the same temperature for 2 hours. After removing 11.11 parts of the solvent at 120 ° C. under reduced pressure (9.3 kPa (70 torr)) using a solvent removal apparatus, 194.24 parts of deionized water and 8.82 parts of dimethylaminoethanol were added to obtain a nonvolatile content. An aqueous solution of 30.0% acrylic resin (containing no hydroxyl group) containing a carboxyl group neutralized with an amine compound was obtained.

<Water-soluble acrylic resin production example 3>
40.0 parts of dipropylene glycol methyl ether was added to the reaction vessel, and the temperature was raised to 120 ° C. while mixing and stirring in a nitrogen stream. Next, a monomer mixture comprising 8.5 parts of methacrylic acid, 54.5 parts of ethyl acrylate, 14.5 parts of 2-hydroxyethyl acrylate, 12.5 parts of methyl methacrylate, 10.0 parts of styrene, and dipropylene An initiator solution consisting of 10.0 parts of glycol methyl ether and 5 parts of tertiary butyl peroxy-2-ethylhexanoate was dropped into the reaction vessel in parallel over 3 hours.

  After completion of the dropping, aging was performed at the same temperature for 0.5 hours. Further, an initiator solution consisting of 5.0 parts of dipropylene glycol methyl ether and 0.3 part of tertiary butyl peroxy-2-ethylhexanoate was added dropwise to the reaction vessel over 0.5 hours. After completion of the dropping, aging was performed at the same temperature for 2 hours. After removing 11.11 parts of the solvent at 120 ° C. under reduced pressure (9.3 kPa (70 torr)) using a desolventizer, 194.24 parts of deionized water and 2.38 parts of sodium hydroxide were added to obtain a nonvolatile content. 30.0% of an aqueous solution of an acrylic resin containing a carboxyl group and a hydroxyl group neutralized with sodium hydroxide was obtained.

(4) Color pigment Table 7 shows the color pigments used.

(4) Aqueous dispersion of colored pigment The acrylic resin shown in Table 6 and the colored pigment shown in Table 7 were mixed and dispersed at room temperature for 1 hour by adding glass bead medium in a paint conditioner to obtain an aqueous dispersion of colored pigment. It was. Table 8 shows the contents (including the acrylic resin solid content with respect to the solid content of 100% by mass of the color pigment) and other commercially available products and their contents.

(5) Colored coating film The aqueous coloring composition (X) for forming a colored coating film contains an aqueous dispersion (A) of the organic resin (a) (the following Production Examples 1 to 5, Table 9), a curing agent ( D) (Table 10), water dispersion (B) (Table 8) of the color pigment (b2), water dispersion (C) (Table 11) of the colloidal silica particles (c), lubricant (F) (Table 12) ) Was blended in the blending amounts shown in Table 13 (described in terms of solid content ratio), and the mixture was stirred using a paint disperser.

  The aqueous coloring composition (X) is applied to the upper layer of the base treatment layer (a metal plate when there is no base treatment layer) formed in the above "Item (2)" with a roll coater, Heating and drying were performed at a predetermined reaching plate baking temperature to form a colored coating film.

<Organic resin production example 1>
In a reaction vessel equipped with a stirrer, condenser and thermometer, 199 parts of terephthalic acid, 232 parts of isophthalic acid, 199 parts of adipic acid, 33 parts of 5-sodium sulfoisophthalic acid, 312 parts of ethylene glycol, 2,2-dimethyl-1,3 -125 parts of propanediol, 187 parts of 1,5-pentanediol and 0.41 part of tetrabutyl titanate were charged, and the esterification reaction was performed from 160 ° C to 230 ° C over 4 hours. Next, the pressure in the system was gradually reduced, the pressure was reduced to 5 mmHg over 20 minutes, and a polycondensation reaction was performed at 260 ° C. for 40 minutes under a vacuum of 0.3 mmHg or less. After adding 20 parts of butyl cellosolve and 42 parts of methyl ethyl ketone to 100 parts of the obtained copolyester resin, the mixture was stirred and dissolved at 80 ° C. for 2 hours, and further 213 g of ion-exchanged water was added to perform water dispersion. Thereafter, the solvent was distilled off while heating, followed by filtration through a 200 mesh nylon mesh to obtain a polyester resin aqueous dispersion (J1) having a solid content concentration of 30%.

<Organic resin production example 2>
In a reaction vessel equipped with a stirrer, condenser and thermometer, 199 parts terephthalic acid, 266 parts isophthalic acid, 199 parts adipic acid, 312 parts ethylene glycol, 125 parts 2,2-dimethyl-1,3-propanediol, 1,5 -187 parts of pentanediol and 0.41 part of tetrabutyl titanate were charged, and the esterification reaction was carried out from 160 ° C to 230 ° C over 4 hours. Next, the pressure in the system was gradually reduced, the pressure was reduced to 5 mmHg over 20 minutes, and a polycondensation reaction was performed at 260 ° C. for 40 minutes under a vacuum of 0.3 mmHg or less. The mixture was cooled to 220 ° C. in a nitrogen stream, and 23 parts of trimellitic anhydride and 16 parts of ethylene glycol bisanhydrotrimellitate were added and reacted for 30 minutes. 100 parts of the obtained copolyester resin, 20 parts of butyl cellosolve and 42 parts of methyl ethyl ketone were added, and then stirred and dissolved at 80 ° C. for 2 hours. Then, 23 parts of isopropyl alcohol and 3.5 parts of triethylamine were added, and 213 parts of ions Water dispersion was performed with exchange water. Thereafter, the solvent was distilled off while heating, followed by filtration with a 200 mesh nylon mesh to obtain a polyester resin aqueous dispersion (J2) having a solid content concentration of 30%.

<Organic resin production example 3>
In a reaction vessel equipped with a stirrer, condenser and thermometer, 199 parts terephthalic acid, 232 parts isophthalic acid, 199 parts adipic acid, 33 parts 5-sodium sulfoisophthalic acid, 250 parts ethylene glycol, 2,2-dimethyl-1,3 -Propanediol 125 parts, 1,5-pentanediol 187 parts, bisphenol A ethylene oxide adduct 62 parts, tetrabutyl titanate 0.41 part were charged, and esterification was performed from 160 ° C to 230 ° C over 4 hours. . Next, the pressure in the system was gradually reduced, the pressure was reduced to 5 mmHg over 20 minutes, and a polycondensation reaction was performed at 260 ° C. for 40 minutes under a vacuum of 0.3 mmHg or less. After adding 20 parts of butyl cellosolve and 42 parts of methyl ethyl ketone to 100 parts of the obtained copolyester resin, the mixture was stirred and dissolved at 80 ° C. for 2 hours, and further 213 g of ion-exchanged water was added to perform water dispersion. Thereafter, the solvent was distilled off while heating, followed by filtration through a 200 mesh nylon mesh to obtain a polyester resin aqueous dispersion (J3) having a solid content concentration of 30%.

<Organic resin production example 4>
230 parts of an average molecular weight 900 polyester polyol synthesized from adipic acid having a hydroxyl group at the terminal and 1,4-butylene glycol, 15 parts of 2,2-bis (hydroxymethyl) propionic acid and 100 parts of N-methyl 2-pyrrolidone And dissolved by heating to 80 ° C. Thereafter, 100 parts of hexamethylene diisocyanate was added, heated to 110 ° C. and reacted for 2 hours, and 11 parts of triethylamine was added for neutralization. This solution was dropped into an aqueous solution obtained by mixing 5 parts of ethylenediamine and 570 parts of ion-exchanged water under strong stirring to obtain a polyurethane resin aqueous dispersion (J4) having a solid content concentration of 30%.

<Organic resin production example 5>
80 parts of a polyester polyol having an average molecular weight of 900 synthesized from adipic acid having a hydroxyl group at the terminal and 1,4-butylene glycol, 120 parts of a 3-mol adduct of bisphenol A propylene oxide having an average molecular weight of 700, and 2,2-bis ( 12 parts of hydroxymethyl) propionic acid was added to 100 parts of N-methyl 2-pyrrolidone and heated to 80 ° C. to dissolve. Thereafter, 100 parts of hexamethylene diisocyanate was added, heated to 110 ° C. and reacted for 2 hours, and 11 parts of triethylamine was added for neutralization. This solution was dropped into an aqueous solution obtained by mixing 5 parts of ethylenediamine and 570 parts of ion-exchanged water under strong stirring to obtain a polyurethane resin aqueous dispersion (J5) having a solid content concentration of 30%.

  <Organic Resin Production Example 6> 100 g of a polyolefin resin (ethylene-methacrylic acid copolymer) copolymerized with a methacrylic acid content of 20% by mass, 5.6 g of sodium hydroxide, and 500 g of water were added to a reaction vessel at 95 ° C. By stirring for 2 hours, an aqueous polyolefin resin dispersion (J6) was obtained.

(6) Colored coated metal plate Tables 13 to 16 show the coating film configuration of the colored coated metal plate prepared in (5) above, the film thickness of the colored coated film, and the ultimate plate baking temperature. In addition, when carbon black is used for the color pigment (B), the particle size of the carbon black dispersed in the coating film is also shown in Table 13. The particle size of the carbon black dispersed in the colored coating film is such that a vertical cross section of the coating film can be seen from the coated metal plate prepared in (1) to (3) above using a FIB (focused ion beam) apparatus. A sample for observation having a thickness of 50 to 100 nm was cut out, and a cross section entering 20 μm in width at any 10 positions of the coating film was observed with a TEM (transmission electron microscope), and the particle diameters at 20 positions were measured arbitrarily. It calculated | required from the average value. Table 13 also shows Y × Z values obtained from the carbon black content (Y mass%) and the thickness (Z μm) of the colored coating film.

(7) Evaluation test About the black coated metal plate (test plate) obtained in (6) above, the designability, moisture resistance, corrosion resistance, workability (designability of the processing portion, processing adhesion) of the flat plate portion, and scratch resistance And chemical resistance were evaluated by the following evaluation methods and evaluation criteria. The evaluation results are shown in Tables 17-20.

(Design of flat plate part)
The appearance of the test plate was evaluated according to the following evaluation criteria.
5: Both coloring and surface gloss are uniform. The groundwork cannot be seen through at all.
4: Although the coloring is uniform, the surface gloss is slightly non-uniform (a level that can be confirmed by looking closely). The groundwork cannot be seen through at all.
3: Coloring and surface gloss are slightly non-uniform (levels that can be confirmed by looking closely). The groundwork cannot be seen through at all.
2: Both coloring and surface gloss are non-uniform (a level that can be easily confirmed). The groundwork cannot be seen through at all.
1: Both coloring and surface gloss are non-uniform (a level that can be easily confirmed). The groundwork is slightly transparent.

(Moisture resistance)
The appearance after the test plate was allowed to stand for 500 hours under conditions of a temperature of 40 ° C. and a humidity of 90% was evaluated according to the following evaluation criteria.
5: No change in appearance is observed.
4: The gloss of the surface slightly decreased (a level at which the test plates before the test were arranged side by side).
3: The gloss of the surface slightly decreased (a level that can be easily understood by arranging the test plates before the test side by side).
2: The gloss of the surface was lowered (a level that can be understood by looking at only the test plate).
1: The gloss of the surface was remarkably lowered (a level that can be easily seen by looking at only the test plate).

(Corrosion resistance)
After tape-sealing the end face of the test plate, a salt spray test (SST) based on JIS Z2371 was performed for 72 hours, and the rust generation state was observed and evaluated according to the following evaluation criteria.
5: No rust generation.
4: Rust generation area is less than 1%.
3: Rust generation area is 1% or more and less than 3%.
2: Rust generation area is 3% or more and less than 5%.
1: Rust generation area is 5% or more.

(Machinability (designability of machined parts))
The test plate was subjected to 180 ° bending, and the outer appearance of the bent portion was evaluated according to the following evaluation criteria. The bending process was performed in an atmosphere of 20 ° C. with a 0.5 mm spacer in between (generally referred to as 1T bending).
5: The coating has no defects such as cracks and has a uniform colored appearance. No discoloration is observed.
4: Since a slight crack is observed in the coating film, a slight color fading is observed, but the appearance is almost uniform. (The level that you can manage by arranging the test plates before the test side by side).
3: Since slight cracks are observed in the coating film, a slight color fading is observed, but the appearance is almost uniform. (The level that can be easily understood by arranging the test plates before the test side by side).
2: Cracks are observed in the coating film, and color fading is observed (a level that can be understood by looking at only the test plate).
1: Cracks were observed in the coating film, and color fading was remarkable (a level that can be easily seen by looking at only the test plate).

(Processability (work adhesion))
After subjecting the test plate to 180 ° bending, a tape peeling test was performed on the outside of the bent portion. The appearance of the tape peeling part was evaluated according to the following evaluation criteria. The bending process was performed in an atmosphere of 20 ° C. with a 0.5 mm spacer sandwiched therebetween (generally called 1T bending).
5: Peeling is not recognized in the coating film.
4: Peeling is observed in a very small part of the coating film (appropriately understood by observation with a magnifying glass).
3: Peeling is observed in a part of the coating film (approximated by observation with a magnifying glass).
2: Peeling is observed in the partial coating film (to the extent that it can be easily seen by visual inspection).
1: Peeling is recognized in most coating films (to the extent that it can be easily seen by visual inspection).

(Scratch resistance)
Five lines were drawn with a pencil lead at an angle of 45 ° on the test plate, and the pencil hardness was evaluated so as not to be damaged more than twice. As the pencil, a uni-pencil manufactured by Mitsubishi Pencil Co., Ltd. was used, tested under a load condition of 20 ° C. and 4.903 N (500 gf), and evaluated according to the following evaluation criteria.
5: Pencil hardness is 3H or more 4: Pencil hardness is 2H
3: Pencil hardness is H
2: Pencil hardness is F
1: Pencil hardness is HB or less

(chemical resistance)
After the test plate was set on a rubbing tester, the state of the film after rubbing the absorbent cotton impregnated with ethanol 10 times with a load of 49.03 kPa (0.5 kgf / cm 2) was evaluated according to the following evaluation criteria.
5: There is no trace on the rubbing surface.
4: A trace is left on the rubbing surface (a level at which the rubbing trace can be discriminated with some attention).
3: Slight marks are left on the rubbing surface (a level at which the rubbing marks can be easily discerned when the eyes are closed).
2: A clear mark is made on the rubbing surface (a level at which the rubbing mark can be identified instantaneously).
1: The coating film dissolves on the rubbing surface, and the base is exposed.

  The examples of the present invention exhibited excellent flat surface designability, moisture resistance, corrosion resistance, workability, scratch resistance, and chemical resistance with a score of 3 or more in any evaluation test. In addition, when the black coating material used for the Example of this invention was left still at 40 degreeC for 1 month, and the storage stability was investigated, the aqueous | water-based coloring composition used in Example 5 and Example 23 was gelatinized. That is, the storage stability of the polyester resin J2 that does not contain a sulfonic acid group is slightly unstable as compared with other colored paints.

  On the other hand, Comparative Examples 1 to 3, which do not contain colloidal silica particles, which are comparative examples outside the scope of the present invention, were inferior in corrosion resistance, work adhesion, and scratch resistance. Comparative Example 4 using a polyurethane resin containing a cationic functional group instead of an anionic functional group as the organic resin was inferior in the planar part designability, the processed part designability, the corrosion resistance, and the chemical resistance. In Comparative Example 5 in which the water-soluble acrylic resin was not used as a dispersant and the carbon black was not previously dispersed with a dispersant, the planar portion designability and the processed portion designability were inferior. In Comparative Example 6 in which the water-soluble acrylic resin was not used as a dispersant and the hydrophilized carbon black was used without being previously dispersed with a dispersant, the corrosion resistance, the processed part designability, and the chemical resistance were inferior. Comparative Example 7 using a water dispersion of carbon black previously dispersed using an anionic surfactant without using a water-soluble acrylic resin as a dispersant was inferior in moisture resistance and corrosion resistance. Comparative Example 7 using a water dispersion of carbon black dispersed in advance using a nonionic surfactant without using a water-soluble acrylic resin as a dispersant has moisture resistance, corrosion resistance, work adhesion, and chemical resistance. It was inferior. Moreover, when the black paint used for the comparative example of this invention was left still at 40 degreeC for 1 month, and the storage stability was investigated, the aqueous | water-based coloring composition used by comparative examples 4-6 was gelatinized.

  As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be envisaged within the scope of the claims, and these are naturally within the technical scope of the invention. Is done.

Claims (15)

  An aqueous dispersion (A) of an organic resin (a) containing an anionic functional group, an aqueous dispersion (B) of a color pigment (b2) dispersed using a water-soluble acrylic resin (b1) as a dispersant, and A colored coating film (α) formed by applying an aqueous coloring composition (X) containing an aqueous dispersion (C) of colloidal silica particles (c) to at least one surface of a metal plate and drying by heating. A chromate-free colored painted metal plate, characterized by comprising:   The chromate-free colored coated metal sheet according to claim 1, wherein the aqueous coloring composition (X) further contains a curing agent (D).   The chromate-free according to claim 1 or 2, wherein the colored pigment (b2) contains carbon black (k), and the thickness of the colored coating film (α) is 2 to 10 µm. Colored painted metal plate.   When the content of the carbon black (k) in the colored coating film (α) is Y mass% and the thickness of the colored coating film (α) is Z μm, Y × Z ≧ 20 and Y ≦ 15. The chromate-free colored painted metal plate according to claim 3, which is satisfied.   Content of the said water-soluble acrylic resin (b1) solid content in the said water dispersion (B) is 5-30 mass% with respect to 100 mass% of solid content of the said carbon black (k), It is characterized by the above-mentioned. The chromate-free colored painted metal plate according to claim 3 or 4.   The chromate according to any one of claims 3 to 5, wherein the carbon black (k) is dispersed in the colored coating film (α) with particles having a number average particle diameter of 20 to 300 nm. Free colored painted metal plate.   The chromate-free colored coated metal plate according to any one of claims 2 to 6, wherein the water-soluble acrylic resin (b1) contains a hydroxyl group in the structure.   The chromate-free colored painted metal plate according to any one of claims 1 to 7, wherein the water-soluble acrylic resin (b1) contains a carboxyl group neutralized with an amine compound in the structure.   The chromate-free colored coated metal plate according to any one of claims 1 to 8, wherein the colloidal silica particles (c) are stabilized with an amine compound.   The organic resin (a) containing the anionic functional group contains at least one functional group selected from an ester group, a urethane group, and a urea group in the structure. The chromate-free colored painted metal plate according to claim 1.   The chromate-free painted metal sheet according to claim 10, wherein at least a part of the anionic functional group is a sulfonic acid metal base.   The chromate-free painted metal sheet according to claim 10 or 11, wherein the organic resin (a) containing an anionic functional group further contains a bisphenol structure in the structure.   The chromate-free colored coated metal sheet according to any one of claims 1 to 12, wherein the aqueous coloring composition (X) further contains a lubricant (E).   The chromate-free colored coated metal sheet according to any one of claims 1 to 13, further comprising a base treatment layer (β) below the colored coating film (α).   An aqueous dispersion (A) of an organic resin (a) containing an anionic functional group, an aqueous dispersion (B) of a color pigment (b2) dispersed using a water-soluble acrylic resin (b1) as a dispersant, and An aqueous coloring composition (X) comprising: an aqueous dispersion (C) of colloidal silica particles (c).