JP2829813B2 - Metallic coating composition and method for forming metallic coating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallic coating composition having a luster suitable for industrial coating of, for example, automobiles, bicycles, home electric appliances and parts thereof, and an industrially advantageous metallic coating film. It relates to the forming method.

[0002]

2. Description of the Related Art Conventionally, mica pigments have been widely used as a coating component for imparting pearly luster to a coating film, and the formation of the coating film is a color intermediate coating obtained by coloring a coating containing the mica pigment. It has been carried out by a three-coat multi-layer coating method in which a clear coat is formed on the coating film. However, this coating system has a drawback of causing color unevenness due to low hiding power and interference characteristic of mica pigment.

[0003] As a paint excellent in concealing performance to compensate for such a disadvantage of the mica pigment, a paint having a combination of a flaky aluminum pigment and a coloring pigment has been proposed. For example, JP-A-2-132171 discloses that rutile-type titanium dioxide (A) and at least 80% by weight of at least 80% by weight of flaky aluminum powder (B) having a particle diameter of 1 to 32 μm are contained in total, The pigment composition having a ratio of (A) / (B) in the range of 99/1 to 90/10 (weight ratio) is used in an amount of 10 to 20 with respect to 100 parts by weight of the resin solid content.
A coating composition contained in a range of 0 parts by weight is disclosed. However, in this composition, the mica pigment is not blended, and the blending amount of the titanium dioxide pigment is large, so that the glitteriness of the flaky aluminum powder cannot be imparted and the color tone becomes cloudy due to the gray color of the aluminum powder. Cause a phenomenon to give.

[0004] Japanese Patent Application Laid-Open No. 2-142882 discloses a glittering paint which solves the above-mentioned problems. At least one carboxylic acid obtained by thermally polymerizing one or more carboxylic acids having a double bond on the surface of a metallic pigment is disclosed. A paint having a composition containing a primary colored metallic pigment obtained by chemically adsorbing a colored pigment via a carboxylic acid having a heavy bond and two carboxyl groups is disclosed. The colored metallic paint carrying this colored pigment exhibits excellent underground concealing properties, but has a drawback in that the color tone remains black (the color tone in which the gray color of an aluminum pigment remains), and it has a pearly milky feeling. Or a feeling of iris cannot be obtained.

On the other hand, as a method of forming a metallic coating film having a brilliant feeling, a metallic paint is used as a clear coat, in which a color paint having a particle size equal to or more than that of the aluminum powder in the metallic paint is mixed. A metallic coating method has been proposed in which two coats are formed on a surface by wet-on-wet (Japanese Patent Application Laid-Open No. 52-144041).
No.). However, even when this coating means is used, it is difficult to suppress a color tone in which blackness remains.

[0006]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies on the composition of the pigment component in order to solve the above-mentioned problems in the conventional glittering metallic paint.
A paint having a composition in which a titanium dioxide pigment and other color pigments, a pigment-carrying flaky aluminum pigment and a pearl pigment are blended in a specific ratio, produces a beautiful milky-white glittering coating with suppressed blackness, and It was confirmed that the composite coating film could be efficiently formed in a two-coat one-bake coating process.

The present invention has been developed on the basis of the above-mentioned findings, and its object is to provide a beautiful pearly milky whiteness and iris with a suppressed blackness color tone and a coating excellent in base layer hiding performance. An object of the present invention is to provide a metallic coating composition capable of forming a film and an industrial coating film forming method therefor.

[0008]

In order to achieve the above object, the present invention provides a metallic coating composition comprising (A) a titanium dioxide pigment, (B) a flake-like aluminum pigment carrying a pigment, and (C) a pigment other than titanium dioxide. Coloring pigment, (D) pearl pigment and (E) coating film forming resin are used as composition components, and these components are (A) / (B) in 2/8 to 6/4 (weight ratio),
[(A) + (B)] / (C) is 99/1 to 80/20
(D) is 20 to 60 parts by weight based on 100 parts by weight of ((A) + (B) + (C)), and the pigment component [(A) is based on 100 parts by weight of the resin solid content of (E). ~ (D)] is 1
It is characterized in that it is contained in each amount ratio of 0 to 60 parts by weight.

Among the pigment components constituting the present invention, (A)
Average particle size 0.2-0.5μm as titanium dioxide pigment
Rutile-type titanium dioxide powder is used. However, ultrafine titanium dioxide pigment having an average particle size in the range of 0.02 to 0.05 μm has a weak coloring power and is not suitable for the purpose of the present invention in terms of hiding properties.

The pigment-bearing flaky aluminum pigment of the component (B) is a metallic pigment obtained by chemically adsorbing an organic or inorganic coloring pigment on the surface of the flaky aluminum pigment, and has a particle diameter of 1 to 50 μm, preferably Is used as a powder in the range of 5-44 .mu.m. The color pigments to be carried are those conventionally used for paints, for example, as organic type, azo lake type pigment, insoluble azo type pigment, condensed azo type pigment, phthalocyanine type pigment, indigo type pigment, perinone type pigment, perylene Pigments, phthalone pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, metal complex pigments, and the like.Inorganic pigments such as graphite, yellow iron oxide, red iron oxide, carbon black,
Titanium dioxide and the like can be mentioned.

The above-mentioned pigment-bearing flaky aluminum pigment (B) is obtained by thermally polymerizing one or more carboxylic acids having a double bond, a carboxylic acid having at least one double bond and two carboxyl groups, and a flake. A heat-polymerized carboxylic acid-treated aluminum pigment obtained by stirring an aluminum pigment in a form of an organic solvent, cooling and filtering, and then dispersing and pulverizing the pigment and then removing the organic solvent can be produced. According to the above, it can be coated with a polymer comprising a monomer having three or more radically polymerizable unsaturated carboxylic acids and radically polymerizable double bonds. These pigments are available under the trade name “Friend Color F500G”
R, F500BL, F500RG, F701BG "(manufactured by Showa Aluminum Powder Co., Ltd.) and the like.

The coloring pigments (C) other than titanium dioxide include:
Various organic and inorganic materials used for paints can be used, and there are no restrictions on the types and components. Therefore, among the above-mentioned coloring pigments exemplified as the supporting coloring pigment, those excluding titanium dioxide can be used.

The pearl pigment (D) is a pigment component having a mica surface coated with titanium dioxide and having a particle diameter of 1 to 44.
Powders in the μm range are used. Especially when the particle size is 10
White mica having a thickness of ４０40 μm and coated with a thin layer of titanium dioxide or interference mica having a relatively thick coating layer is preferably used. In addition, those coated with another metal oxide or the like in order to enhance water resistance can also be used.

Acrylic resin, polyester resin, alkyd resin, fluorine resin and the like are applied as the resin of the component (E) to be a vehicle for forming a coating film, and are usually mixed with a crosslinking agent such as an amino resin or a blocked isocyanate. Provided for use. Further, these resins are not limited to one kind, and two or more kinds can be used in combination. In addition, a two-component polyurethane resin or silicone resin that can be cured by drying at room temperature is also used.

In combination with the above-mentioned components (A) to (E), these components are converted by weight ratio of (A) / (B) to 2/8 to 6 /
4, [(A) + (B)] / (C) is 99/1 to 80/2
The ratio of (D) is 20 to 60 parts by weight per 100 parts by weight of [(A) + (B) + (C)], and the pigment component [(A) to 100 parts by weight of the resin solid content of (E)]. (D)] is an important requirement in the constitution of the invention to be contained in an amount ratio of 10 to 60 parts by weight, and when the amount ratio is out of this range, the desired blackness of the formed coating film is suppressed. It is impossible to form a coating film exhibiting a brilliant pearly milky white feeling and an iris feeling and exhibiting excellent hiding properties.

That is, when the ratio of (B) to (A) exceeds 2/8 (80% by weight), the metallic feeling is overemphasized and the pearly milky feeling disappears, and the ratio of (B) is 6%. If the ratio is less than / 4 (40% by weight), the opacity of titanium dioxide becomes strong, and the iris and glitter are lost. [(A)
When the ratio of (C) to + (B)] is less than 99/1 (1% by weight), only a light color can be obtained, so that selection of color tone is limited, and when it exceeds 80/20 (20% by weight), dark color It becomes too pearly milky white color.
If the proportion of the pearl pigment of (D) is less than 20 parts by weight with respect to 100 parts by weight of the ((A) + (B) + (C)) component, the iris is reduced and exceeds 60 parts by weight. Then, the underlying layer concealing performance is lowered, and it is necessary to adopt a multilayer coating process. Also,
[(A) + (B) + (C)]
+ (D)] if the blending amount of all the pigment components is less than 10 parts by weight, the hiding power is insufficient, and if it exceeds 60 parts by weight, it approaches the critical PWC and the smoothness of the coating film is impaired, leading to poor appearance.

A more preferable compounding ratio is (A) /
(B) is 2/8 to 4/6 (weight ratio), [(A) +
(B)] / (C) is 95/5 to 85/15 (weight ratio),
[(A) + (B) + (C)] per 100 parts by weight (D)
The total amount of the pigment components [(A) to (D)] is in the range of 15 to 40 parts by weight per 40 to 50 parts by weight and 100 parts by weight of the resin solid content of (E).

Although the metallic coating composition of the present invention is mainly composed of the above-mentioned components, various additives commonly used in conventional coating compositions can be arbitrarily compounded.
Examples of the additive include a curing catalyst such as dodecylbenzenesulfonic acid, a benzotriazole-based ultraviolet absorber, a benzophenol-based antioxidant, a surface conditioner such as silicone and an organic polymer, a sagging agent, and a thickener. Is used as appropriate. These components are usually contained in the film-forming resin 10.
The performance of paints and coatings can be improved with a blending amount of 5 parts by weight or less with respect to 0 parts by weight.

The metallic coating system of the present invention having the above-mentioned component composition is generally of the organic solvent type, but is not limited thereto, and may be of various types such as non-aqueous dispersion type, aqueous solution type and dispersion type. Can be composed as a paint. At the time of coating, the mixture is diluted with a solvent such as an organic solvent or water to a viscosity suitable for coating, and the solid content at the time of coating is preferably 10 to 50% by weight.

The method for forming a metallic coating film according to the present invention comprises:
(A) titanium dioxide pigment, (B) pigment-bearing flaky aluminum pigment, (C) coloring pigment other than titanium dioxide,
(D) Pearl pigment and (E) a film-forming resin are used as composition components, and these components are (A) / (B) in a ratio of 2/8 to 6/4 (weight ratio), [(A) + (B)]. / (C) is 99/1 to 80
/ 20 (weight ratio), [(A) + (B) + (C)] 100
(D) is 20 to 60 parts by weight with respect to 100 parts by weight of the resin solid content of (E), and the total amount of the pigment components [(A) to (D)] is 10 to 60 parts by weight. After a base coat is applied to the surface of the base material to be coated, the clear paint is top-coated, and the base coat and the top coat are simultaneously cured.

The substrate to be coated includes inorganic materials such as metals such as iron, aluminum, copper and their alloys, glass, cement, concrete, and the like.
Polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyacryl, polyester,
Resin molded products such as ethylene-polyvinyl alcohol copolymer, vinyl chloride resin, vinylidene chloride resin, polycarbonate, and polyurethane, and plastic materials such as various FRPs, wood, and fiber materials are applicable. It is optional to apply an appropriate undercoat or precoat treatment to these substrates in advance.

The coating can be carried out directly on the substrate to be coated. For example, in the case of coating an automobile, for example, undercoating and intermediate coating with an electrodeposition paint or the like after a surface chemical conversion treatment, and coating after the coating film is cured I do. The coating operation is performed by air spray coating, electrostatic coating or the like using an atomizing type coating machine. Base coat film is 10-25 μm
It is preferable to form the film in the range of the dry film thickness. If the film thickness is less than 10 μm, the base concealing property is reduced, causing color unevenness.

Next, a clear top coating is applied as a top coat on the base coat. As the clear paint, a transparent resin generally used is generally used, but if necessary, a coloring pigment or various additive components may be blended as long as the transparency is not impaired. Base coat and top coat are 2
The coating is simultaneously cured by a coat 1 baking method to form a composite coating film. The preferred dry film thickness of the formed top coat is 30 to 60 μm.

[0024]

According to the metallic coating composition of the present invention, the pigment components (A) to (D) blended in a specific ratio have an effect of giving the formed coating film a unique glitter. In other words, the coloring pigment interposed on the surface of the pigment-carrying flake-like aluminum pigment (B) reduces the turbid color due to the flip-flop inherent to the aluminum pigment, exhibits excellent brilliant color tone, and has sufficient concealment performance against the base. Demonstrate. At the same time, the titanium dioxide pigment (A) creates a pearly milky feeling by being used in combination with the pearl pigment while imparting a high hiding power, and the pearl pigment (D) is an iris that cannot be exhibited by the pigment-carrying flaky aluminum pigment (B). It works to create a feeling. The function of each of these components is combined to give a unique pearly milky whiteness and iris along the hue of the coloring pigment (C) other than the titanium dioxide pigment while suppressing the blackness, and an extremely beautiful brilliant metallic. A system coating is formed. Further, by changing the color pigment of the pigment-supporting flaky aluminum pigment in this component composition, various color sensations can be created, so that the effect of remarkably expanding the color tone selection range can be obtained.

Further, according to the method for forming a metallic coating film according to the present invention, the base coat and the top coat are always subjected to two-coat one-bake coating on the basis of the functions of the brilliancy and the base concealing performance by the component composition of the metallic paint described above. Since a normal glittering metallic coating film without color unevenness can be formed, the coating process can be simplified.

[0026]

Hereinafter, examples of the present invention will be described in comparison with comparative examples. The specific components (A) to (E) constituting the applied metallic coating composition are as follows. The components shown in Tables 1 to 3 are indicated by the following symbols. Also,
The amount is shown in parts by weight of the solid content, and (A), (B),
The amounts of (C) and (D) were expressed as parts by weight of each pigment component alone.

(A) Titanium dioxide pigment: A titanium dioxide paste prepared as follows was used. (A-1) 40.0 parts by weight of trade name “Taipaek CR-95” (manufactured by Ishihara Sangyo Co., Ltd.) and acrylic resin varnish
3 parts by weight were premixed with a dissolver and dispersed by a sand grind mill until the particle size became 10 μm or less. Then, 7.8 parts by weight of the melamine resin varnish, 0.3 parts by weight of triethylamine and 14.6 parts by weight of the solvent (F-1) were added and mixed with a dissolver for 20 minutes. (A-2) 40.0 parts by weight of trade name "Taipaek CR-95" (manufactured by Ishihara Sangyo Co., Ltd.), polyester resin (E-
3) Using 37.3 parts by weight of varnish, 16.0 parts by weight of melamine resin (E-4) varnish, 0.3 parts by weight of triethylamine and 6.4 parts by weight of solvent (F-2), (A-1) Similarly, they were dispersed and mixed.

(B) Pigment-supporting flaky aluminum pigment; (B-1) Trade name "Friend Color F500GR" [manufactured by Showa Aluminum Powder Co., Ltd., solid content 48%] (B-2) Trade name "Friend Color F500BL" (Showa Aluminum Powder Co., Ltd., solid content 48%) (B-3) Trade name "Friend Color F500RG" [Showa Aluminum Powder Co., Ltd., solid content 51%] (B-4) Trade name "AL Paste 7160N "[Toyo Aluminum Co., Ltd., solid content 65%]. Aluminum pigment not carrying pigment used for comparative example

(C) Color pigment: A primary color paste prepared as follows was used. (C-1) Trade name "Palio Thor Yellow 2140HD" [B
ASF] 7.8 parts by weight, acrylic resin (E-1) varnish 46.7 parts by weight, melamine resin (E-2) varnish 9.7 parts by weight, triethylamine 0.4 parts by weight, solvent (F-1) Using 34.4 parts by weight, the mixture was dispersed and mixed in the same manner as in (A-1). (C-2) Product name “Shinkasha Magenta RT-343D”
[CIBAGEIGY] 13.4 parts by weight, acrylic resin (E-1) varnish 40.2 parts by weight, melamine resin (E-2) varnish 8.4 parts by weight, triethylamine 0.
Using 4 parts by weight and 37.6 parts by weight of the solvent (F-1),
It was dispersed and mixed in the same manner as (A-1). (C-3) Trade name "Shanin Blue G-500N" (manufactured by Sanyo Dyeing Co., Ltd.) 9.0 parts by weight, acrylic resin (E-1) varnish 65.6 parts by weight, melamine resin (E-2) varnish 1
3.6 parts by weight, 0.5 parts by weight of triethylamine and 11.3 parts by weight of the solvent (F-1) were dispersed and mixed in the same manner as in (A-1). (C-4) Trade name “Shanin Blue G-500N” [manufactured by Sanyo Dyeing Co., Ltd.] 8.0 parts by weight, polyester resin (E-
3) Using 57.5 parts by weight of varnish, 19.2 parts by weight of melamine resin (E-4) varnish, 0.5 parts by weight of triethylamine and 14.8 parts by weight of solvent (F-2), (A-1) Similarly, they were dispersed and mixed.

(D) Pearl pigment; (D-1) Trade name “Iriodin 103WII” (manufactured by Merck) (D-2) Trade name “Exterior Marlin Russet” (manufactured by Marl) (D-3) Trade name “ Exterior Marlin Super Blue (Mal)

(E) Coating resin; (E-1) Acrylic resin (styrene / methyl methacrylate / ethyl acrylate / hydroxyethyl methacrylate / methacrylic acid copolymer, number average molecular weight 2000)
0, hydroxyl value 45, acid value 15, solid content 50%) (E-2) Melamine resin [trade name "Uban 20SE" manufactured by Mitsui Toatsu Chemicals, Inc., solid content 60%] (E-3) Polyester resin [Product name "Beccosol EZ
3520-60 "manufactured by Dainippon Ink and Chemicals, Inc., solid content 60%] (E-4) Melamine resin [trade name" Super Beckamine L- "
117-60 "manufactured by Dainippon Ink and Chemicals, Inc., solid content 60%]

Examples 1 to 10 and Comparative Examples 1 to 11 The components (A) to (E) were mixed with the organic solvent F-1 (toluene / xylene / ethyl acetate / butyl acetate) at the composition ratios shown in Tables 1 to 3. 70/15/10/5) Or organic solvent F-2 (Solvesso 150 / xylene / butyl acetate = 60/30/10; Solvesso 150 is an aromatic hydrocarbon solvent manufactured by Exxon) and dispersing for 15 minutes to suitability for coating A metallic coating was prepared by stirring and mixing to obtain a viscosity.

Using the obtained metallic paint of each composition,
A coating film was formed by the following coating process. A cationic electrodeposition coating [Nippon Paint Co., Ltd., "Power Top U-5"
0 "] was applied so that the dry coating film became 25 μm, and baked at 160 ° C. for 30 minutes. An intermediate coating material (“ Olga S-90 Sealer ”manufactured by Nippon Paint Co., Ltd.) was applied to the surface of the electrodeposited coating film. Was air-sprayed so that the dry film thickness was 40 μm, and baked at 140 ° C. for 30 minutes to produce a test plate, and a metallic paint was applied on the surface of the test plate so that the dry film thickness was 16 to 20 μm. Coating was performed using an electrostatic coating machine (Auto REA, manufactured by Landsberg Gemma Co., Ltd.) at an atomization pressure of 2.8 kg / cm ² , and the atmosphere in the booth during coating was maintained at a temperature of 25 ° C. and a humidity of 75%. After setting for 3 minutes after painting, clear acrylic resin [Nippon Paint Co., Ltd., "Super Rack 0-10"
0 ″] was applied to a dry film thickness of about 35 μm. After setting at room temperature for about 10 minutes,
Bake at 300C for 30 minutes.

With respect to the formed coating film, pearly milky feeling, iris feeling and concealing property were judged and evaluated by visual observation according to the following criteria, and the concealing film thickness was measured at the same time. (1) Milky feeling; ○… Milky feeling △… Blackish milky feeling ×… No milky feeling (2) Iris feeling; ○… Clear iris feeling △… Weak iris feeling, strong metallic feeling ×… Iris feeling None (3) Opacity; ○… No undercoat is transparent ×… Undercoat is transparent (4) Concealed film thickness: Painted on opacity test paper specified in 7.2 of JIS K5400 7.2, and discrimination of boundary between black and white ground The film thickness at which no film could be formed was measured.

The obtained evaluation results are shown in Tables 1 to 3 in comparison with the component compositions of the used metallic paints.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

As is apparent from a consideration of Tables 1 to 3, each coating film formed by two coats and one bake coating using the metallic paint having the component composition of the present invention has a pearly milky white having no blackish feeling. It had excellent glittering properties, giving a sense of sensation and iris, and had a sufficient background hiding power. On the other hand, the formed coating film of the comparative example which did not satisfy any of the specific requirements of the present invention could not satisfy all of the opalescent feeling, the iris feeling or the hiding property. In Comparative Example 11, the evaluation of the glitter was good because the amount of all the pigment components was too large, but it was recognized that the smoothness of the coating film was significantly reduced.

[0040]

As described above, according to the present invention, four types of (A) titanium dioxide pigment, (B) flake aluminum pigment carrying pigment, (C) coloring pigment other than titanium dioxide, and (D) pearl pigment. (E) By adding the pigment component of (A) to the film-forming resin in a specified quantitative ratio, a glittering coating film exhibiting a unique beautiful pearl milky whiteness and iris feeling which could not be obtained by the prior art is formed. A metallic coating composition that can be used. Further, according to the method for forming a metallic coating film according to the present invention, it is possible to perform a coating operation in an efficient process using a two-coat, one-bake coating system using a coating material having the above-described composition. Therefore, it is extremely useful for the purpose of forming a high-quality brilliant coating film on various substrates to be coated, including the exterior coating of an automobile body requiring a high-grade coating color.

Claims (2)

(57) [Claims] 1. A composition comprising (A) a titanium dioxide pigment, (B) a flake-like aluminum pigment carrying a pigment, (C) a coloring pigment other than titanium dioxide, (D) a pearl pigment, and (E) a film-forming resin. And (A) / (B) are 2 /
8 to 6/4 (weight ratio), [(A) + (B)] / (C) is 99/1 to 80/20 (weight ratio), [(A) + (B) +
(C)] 20 to 60 parts by weight of (D) based on 100 parts by weight, and pigment component based on 100 parts by weight of resin solid content of (E).
A metallic coating composition, wherein the total amount of [(A) to (D)] is 10 to 60 parts by weight. 2. On the surface of a substrate to be coated, (A) a titanium dioxide pigment, (B) a flaky aluminum pigment carrying a pigment, (C) a coloring pigment other than titanium dioxide, (D) a pearl pigment, and (E) a coating. The film forming resin is used as a composition component, and (A) / (B) is 2/8 to 6/4 (weight ratio), [(A)
+ (B)] / (C) is 99/1 to 80/20 (weight ratio), (D) is 20 to 60 parts by weight with respect to [(A) + (B) + (C)] 100 parts by weight, (E) 100 resin solids
The total amount of the pigment components [(A) to (D)] is 10 to 6 parts by weight.
A method for forming a metallic coating film, comprising: after a base coat of a metallic paint containing 0 parts by weight, a top coat of a clear paint, and simultaneously curing the base coat and the top coat.