JP2002121488A - Coating composition and method for forming laminated coating film and the resultant laminated coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition favorably usable as an automotive coating, causing no color chippings even after long-term use outdoors, and capable of giving coating film of high chroma. SOLUTION: This coating composition contains, as color pigment components, a colored aluminum pigment and an auxiliary color pigment; wherein the two kinds of pigments are characterized by that their hues of the 10 hue circles of the Munsell color system are akin to each other, the chroma difference in the Munsell color system is <=5 and the lightness difference is <=3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition containing a colored aluminum pigment, and more particularly to a coating composition which can be suitably used as a coating composition for automobiles and has high color saturation. The present invention relates to a coating composition which can be used, a method for forming a multilayer coating film using the same, and a multilayer coating film.

[0002]

2. Description of the Related Art In the case of overcoating of automobile bodies and the like,
Painting using a glittering material such as aluminum flake and mica powder is known. In the case of such a top coat containing a glittering material, a method of forming a base coating film containing a glittering material and a coloring pigment and then forming a clear coating film thereon is employed.

JP-A-11-114489 discloses a color base paint containing a coloring pigment, a glitter-containing base paint containing a glitter material, and a clear paint for the purpose of sufficiently exhibiting the glitter of the glitter material. There is disclosed a method of forming a laminated coating film in which a coating material is applied by wet-on-wet and then baked to cure the coating film.

[0004] Among the brilliant materials, colored aluminum pigments are used in paints for various applications because they have high chroma and lightness and are excellent in design. However, a coating film containing a colored aluminum pigment has poor weather resistance, and can show color skipping when used outdoors for a long period of time.

Japanese Patent Application Laid-Open No. Hei 5-70719 discloses a metallic paint containing a flaky colored aluminum pigment and mica powder, which uses the above-mentioned colored aluminum pigment. It was not enough in terms of saturation.

[0006]

DISCLOSURE OF THE INVENTION The present invention is suitable for use as a coating material for automobiles, and provides a high-colored coating film which does not show color skipping due to long-term outdoor use. To provide a coating composition that can be used.

[0007]

According to the present invention, there is provided a coating composition containing a coloring aluminum pigment and an auxiliary coloring pigment as a coloring pigment component, wherein the coloring aluminum pigment and the auxiliary coloring pigment each have a Munsell-displayed 10 hue. A paint composition characterized in that the hues of the rings are similar colors, the difference in saturation in Munsell display is 5 or less, and the difference in lightness is 3 or less.

The present invention also provides a step of forming a color base coating film on a substrate; forming a metallic base coating film on the color base coating film, and forming a clear coating film thereon without curing the metallic base coating film. A step of curing the metallic base coating film and the clear coating film by heating; and
The metallic base coating film is obtained by applying a coating composed of the coating composition, and the colored aluminum pigment in the metallic base coating film and the color base coating film have a difference of 3 or less in Munsell hue. A method for forming a laminated coating film. The present invention is also a laminated coating film formed by the above-described method for forming a laminated coating film. Hereinafter, the present invention will be described in more detail.

[0009]Paint composition  The coating composition of the present invention comprises a coloring pigment component as a coloring pigment component.
It contains a minium pigment and an auxiliary coloring pigment. Coloring
Used in combination with aluminum pigment and auxiliary coloring pigment
The resulting coating is colored aluminum
Superior design properties while maintaining the high chroma and lightness of pigments
Color jumps even after long-term outdoor use
Does not occur. Therefore, suitable as an automotive coating composition
Can be used for

In the present invention, as the above-mentioned colored aluminum pigment and the above-mentioned auxiliary colored pigment, those having the same hue in the 10-color hue circle of Munsell display are used. The hue of the 10 hue ring in the Munsell display is similar to the hue of the colored aluminum pigment itself and the hue of the auxiliary coloring pigment itself when the hue of the auxiliary color pigment itself is the same in the Munsell display. Means For example, when the hue of the colored aluminum pigment itself is represented by Munsell notation composed of 10 hue rings and is 5R, the auxiliary color pigments having the same hue in the range of 1R to 10R are used. If the colors are not the same, the saturation of the resulting coating film is reduced, and the high hue and saturation of the colored aluminum pigment cannot be exhibited.

Further, it is preferable to use, as the colored aluminum pigment and the auxiliary colored pigment, those having a Munsell display hue difference of 3 or less. For example, when the hue of the colored aluminum pigment itself is represented by Munsell notation consisting of 10 hue rings and is 5R, the auxiliary color pigments have the same hue and the difference in hue is 3 or less. Use those in the range of 2R to 8R.

In the present invention, as the colored aluminum pigment and the auxiliary colored pigment, those having a difference in chroma in Munsell display of 5 or less and a difference in lightness of 3 or less are used. If the difference in saturation exceeds 5, or the difference in lightness exceeds 3,
The saturation and lightness of the resulting coating film decrease, and a coating film with a vivid color tone cannot be obtained.

In the present invention, the auxiliary color pigment is defined as having a similar color to the hue of the 10 hue circle in Munsell display with a difference of 5 or less and a difference in brightness of 3 or less in Munsell display, based on the colored aluminum pigment. Satisfy the following conditions, and
It means a coloring pigment not containing an aluminum pigment.

The amount of the auxiliary coloring pigment is 100 parts by weight of the coloring aluminum pigment in terms of solid content.
It is preferable to mix in 20 to 800 parts by weight. When the amount is less than 20 parts by weight, the obtained coating film is inferior in weather resistance, and color flying may occur due to long-term outdoor use. 8
If the amount is more than 00 parts by weight, the saturation of the obtained coating film is lowered.
More preferably, it is 50 to 700 parts by weight, and still more preferably 70 to 600 parts by weight.

Examples of the auxiliary coloring pigments include various organic and inorganic coloring pigments, such as organic azo lake pigments, insoluble azo pigments, condensed azo pigments, diketopyrrolopyrrole pigments, and benzene pigments. Imidazolone pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, metal complex pigments;
Examples include inorganic graphite, yellow iron oxide, red iron oxide, carbon black, titanium dioxide and the like. These may be used alone or in combination of two or more.

The above-mentioned colored aluminum pigment is obtained by coating the above-mentioned pigment as an auxiliary colored pigment on an aluminum pigment by a wet method. The aluminum pigment has an average particle size (D ₅₀ ) of about 3 to 50 μm, preferably about 5 to 45 μm, and has a thickness of about 0.1 to 50 μm.
Those having a thickness of 1 to 2 μm are preferred. The coating layer of the color pigment has a thickness of about 80 to about 600 nm. The coating of the coloring pigment is, for example, one in which the polymer is dispersed in water at the same time as the polymer substance and is deposited on the surface of the aluminum pigment to form a coloring layer continuously, with good adhesion, and smoothly.

As the colored aluminum pigment, a colored metallic pigment described in JP-A-1-315470 can be used. The colored metallic pigment is obtained by thermally polymerizing one or more carboxylic acids having a double bond on the surface of an aluminum pigment via a carboxylic acid having one or more double bonds and two or more carboxyl groups. A primary color pigment obtained by chemically adsorbing a color pigment, or a secondary color pigment obtained by coating the primary color pigment with a polymer comprising a radical polymerizable unsaturated carboxylic acid and a monomer having three or more radical polymerizable double bonds. Next is a coloring pigment.

Specifically, as a red-colored aluminum pigment, "98-4008R" manufactured by Toyo Aluminum Co., Ltd.
E "," 99-4048RE "," 97-4084R "
E "and the like, and" D-
554RE ". In addition, as a colored aluminum pigment that can exert the same effect, for example, in the case of a blue-based colored aluminum pigment, “98-4012BL” and “96-4072” manufactured by Toyo Aluminum Co., Ltd.
BL ”and the like.
-551BL "," F-500BL "," F-701B "
L "and the like. Further, among yellow-colored aluminum pigments, “96-4017” manufactured by Toyo Aluminum Co., Ltd.
YE ”and the like.
-529YE "and the like.

In the coating composition of the present invention, the pigment concentration (P
(WC) in the range of 1 to 10% by weight. If it exceeds 10% by weight, the appearance of the coating film will be reduced, and if it is less than 1% by weight, the saturation will not be improved. Preferably, 1 to
7% by weight.

The coating composition of the present invention may contain a coloring pigment and a mica pigment in order to adjust the obtained coating composition to a desired color tone, in addition to the coloring aluminum pigment and the auxiliary coloring pigment. it can. Further, a non-colored aluminum pigment can be used in combination. The color pigment is not particularly limited, and examples thereof include those exemplified for the auxiliary color pigment.

The above mica pigments are those usually used in metallic base paints, and include, for example, interference mica pigments, colored mica pigments, white mica pigments and the like. Although the shape is not particularly limited, for example, scaly ones are preferable, and the average particle size (D ₅₀ ) is 2 to ₅₀ μm,
Further, those having a thickness of 0.1 to 3 μm are suitable.

The above-mentioned interference mica pigment, colored mica pigment and white mica pigment are prepared by adding TiO 2 on the surface of the mica pigment.
₂ , SnO ₂ , ZrO ₂ , Fe ₂ O ₃ , ZnO ₂ , Cr
A mica pigment coated with a metal oxide such as ₂ O ₃ , V ₂ O _5, etc. and their hydrates, which has a pearl foil-like, metal-like and iridescent effect. It gives the color feeling that the thickness plays. Among them, those uniformly coated with metal oxides such as TiO ₂ and Fe ₂ O ₃ are preferably used.

For example, as an interference mica pigment having a white interference color, "Silalic T" manufactured by Merck Japan Ltd.
60-10 W3 "(trade name)," Pearl Grace SME 90-9 "(trade name) manufactured by Nippon Koken Co., Ltd. As an interference mica pigment having a green interference color," Iriodin Ultra 7235 W2 "manufactured by Merck Japan Ltd. (Trade name), "Iriodin Ultra 7225 W" manufactured by Merck Japan Ltd. as interference mica having a blue interference color
2 (trade name), "Iriodin Ultra 7" manufactured by Merck Japan Ltd. as an interference mica having an interference color of yellow
205 W2 "(product name). Further, as the mica pigment having the interference light, an alumina flake pigment (alumina white, blue, red, green, gold) having the interference light can be used.

The coating composition of the present invention preferably contains the above mica pigment. By including the mica pigment, a coating film having excellent glitter and flip-flop properties and having an excellent metallic feeling even in a region having high brightness and saturation can be obtained. The pigment concentration (PWC) of the mica pigment in the coating composition is generally 18% by weight or less. If it exceeds 18% by weight, the appearance of the coating film is reduced. Preferably, it is 0.01 to 17% by weight, more preferably 0.01 to 16% by weight.

[0025] The coating composition of the present invention further comprises an extender pigment,
It may contain a film-forming resin, a curing agent and the like. The extender is not particularly limited, and examples thereof include calcium carbonate, barium sulfate, clay, and talc. In the present invention, the total pigment concentration (PWC) in the paint including all the pigments such as the coloring pigment and the extender is 3 to 70% by weight, preferably 4 to 65% by weight.
%, More preferably 5 to 60% by weight. If the content exceeds 70% by weight, the appearance of the obtained coating film is deteriorated.

Examples of the film-forming resin and the curing agent include a film-forming resin such as an acrylic resin, a polyester resin, an alkyd resin, and a fluorine-based resin, and a curing agent such as an amino resin and / or a block polyisocyanate compound. Used. When the coating composition of the present invention is used as an aqueous type, US Pat.
No. 504 or the like can be used. The preferred solid content of the coating film forming resin and the curing agent in the coating composition is 30 to 7 at the time of production.
0% by weight and 10 to 50% by weight at the time of application.

A viscosity controlling agent can be added to the above coating composition in order to ensure coating workability. As the viscosity controlling agent, those which generally exhibit thixotropic properties can be used, for example, amide-based swelling dispersions of fatty acid amides, amide-based fatty acids, and long-chain polyaminoamide phosphates; colloidal swelling of polyethylene oxide Dispersion and other polyethylene-based materials; organic acid smectite clay and organic bentonite such as montmorillonite; inorganic pigments such as aluminum silicate and barium sulfate; flat pigments that exhibit viscosity depending on the shape of the pigment; cross-linked or non-cross-linked And the like.

The amount of the viscosity control agent to be added to the above coating composition is 0.1 to 100 parts by weight of the resin solid content of the coating composition.
0.01 to 10 parts by weight, preferably 0.02 to 8 parts by weight, more preferably 0.03 to 6 parts by weight. If the amount exceeds 10 parts by weight, the appearance of the obtained coating film is reduced, and if the amount is less than 0.1 part by weight, the effect of controlling the viscosity cannot be obtained, which may cause break-in or inversion between layers.

The coating composition of the present invention may contain other additives, if desired. Examples of the additive include a surface conditioner such as silicone and an organic polymer, an ultraviolet absorber, a hindered amine, and a hindered phenol. These amounts are within the range known to those skilled in the art.

The total solid content of the coating composition of the present invention is 10
６０60% by weight, preferably 15-55% by weight. The coating form of the coating composition of the present invention may be any of an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion) and a non-aqueous-dispersed type.
An ultraviolet absorber, an antioxidant, a surface preparation agent and the like can be used.

The method for producing the coating composition used in the present invention is not particularly limited, including those described below, and those skilled in the art such as kneading and dispersing a compound such as a pigment using a kneader or a roll. Well-known methods can be used.

[0032]Method of forming laminated coating film  The method for forming a laminated coating film of the present invention comprises the steps of:
Forming a coating film on the color base coating film
Lick-based coating, and without curing it,
Forming a clear coating on the substrate; and heating
The above-mentioned metallic base coating film and clear coating film
Curing step. Lamination of the present invention
In the method for forming a coating film, the metallic base coating film
Is obtained by applying a paint comprising the above-described paint composition.
Things.

In the present invention, the colored aluminum pigment in the metallic base coating film and the color base coating film have a Munsell hue difference of 3 or less. In the present specification, the difference between the hue of the colored aluminum pigment in the metallic base coating film and the hue of the color base coating film in the Munsell display of 3 or less is defined as the hue of the colored aluminum pigment itself contained in the metallic base coating film. And the hue indicated by the color base coating film are colors adjacent to each other, adjacent colors, or adjacent colors in the color arrangement of the Munsell color system hue circle (10 hues). It means that they are in a relationship. For example, when the hue of the colored aluminum pigment itself contained in the metallic base coating film is represented by Munsell notation of 10 hue rings, 5R
In the case of, the hue of the color base coating film is 2R
Ｒ8R.

When the ratio is out of the above range, the coating color cannot be stably designed as the laminated coating film, and the hue may be uneven or the color tone may be changed due to a slight fluctuation of the coating film thickness. Therefore, it is preferable that the above-mentioned hue difference is adjacent colors or adjacent colors, and more preferably, adjacent hues. For example, when the hue of the colored aluminum pigment itself contained in the metallic base coating film is 5R, the hue of the color base coating film is more preferably 3R to 7R, and still more preferably 4R to 7R.
6R. In the present invention, it is most preferable that a substantial difference in hue does not occur.

[0035]Color base coating  In the method for forming a laminated coating film of the present invention, the color base coating
A color base paint is used to form the film. Up
Color base paints include color pigments, extender pigments,
It contains a forming resin, a curing agent and the like.

The color pigments contained in the color base paints include those mentioned as the auxiliary color pigments, and the extenders described above can be mentioned. These may be used alone or in combination of two or more.

For example, as a coloring pigment to be contained in the color base paint, for example, in the case of a red pigment, a quinacridone pigment, an iron oxide pigment, a perylene pigment or the like is mainly used, and the content in the color base paint is 0.01%. ~ 50
By adjusting the pigment concentration (PWC) to a percentage by weight, a color base coating film having good hiding properties can be obtained. If the amount is less than 0.01% by weight, the underlying layer concealing property is reduced, and if it is more than 50% by weight, the appearance of the obtained coating film is reduced. Preferably it is 0.1 to 20% by weight. By containing the red pigment in the above range, a red color base coating film having a Munsell value hue (H) of 2.5R to 10R can be formed.

The total pigment concentration (PWC) in the above color base paint is 3 to 70% by weight, preferably 4 to 65% by weight, more preferably 5 to 60% by weight.
% By weight. When the content exceeds 70% by weight, the appearance of the coating film deteriorates.

As the coating film forming resin and the curing agent, for example, those described above can be used. Furthermore, the above color base paint, in order to ensure the workability of painting,
The above-mentioned viscosity controlling agent can be added, and the above-mentioned additive can be contained.

The color base paint used in the present invention is:
In general, a solution type is preferably used. If the solution type is used, any of an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion) and a non-aqueous type may be used. These preferred solids contents in the coating material are in the range of 30 to 70% by weight at the time of production and 10 to 50% by weight at the time of application.

[0041]Clear coating  In the method for forming a laminated coating film of the present invention, the clear coating film
A clear paint is used for the formation. Clear coating above
The material contains a film-forming resin, a curing agent, and the like. The above coating
The forming resin is not particularly limited.
Kuril resin, polyester resin, epoxy resin, urethane
Film-forming resins such as
Are amino resins and / or blocked isocyanate resins
Used in combination with a curing agent such as Transparency or
In terms of acid etching resistance and the like, acrylic resin and / or
Combination of polyester resin and amino resin, or
Acrylic resin having rubonic acid / epoxy curing system and / or
Alternatively, a polyester resin or the like can be used.

The solid content in the clear coating is 2
It is 0 to 60% by weight, preferably 35 to 55% by weight. The solid content at the time of application is 10 to 50% by weight, preferably 20 to 50% by weight.

The above-mentioned clear coating is applied in an uncured state after application of the mica-based coating, so that the coating is formed by a so-called wet-on-wet method. Therefore, it is preferable to contain the viscosity control agent described above. The content is 0.01 to 10 parts by weight, preferably 0.02 to 8 parts by weight, per 100 parts by weight of the resin solid content of the top clear coating composition.
Parts by weight, more preferably from 0.03 to 6 parts by weight. If the amount exceeds 10 parts by weight, the appearance is deteriorated, and
If the amount is less than the weight part, the effect of controlling the viscosity cannot be obtained, which may cause problems such as sagging.

The form of the clear paint used in the present invention may be any of an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), a non-aqueous dispersion type, and a powder type. A catalyst, a surface preparation agent and the like can be used.

[0045]Base material  The method for forming a laminated coating film of the present invention includes various substrates, for example,
Metal, glass, cloth, plastic, foam, etc., especially metal
Cationic electrodeposition, which can be used advantageously for surfaces and castings
It can be used particularly preferably for paintable metal products.

The metal products include, for example, iron, copper,
Aluminum, tin, zinc, and the like, and alloys containing these metals are included. Specific examples include automobile bodies and parts such as passenger cars, trucks, motorcycles, and buses. It is particularly preferable that these metals have been previously subjected to a chemical conversion treatment with a phosphate, a chromate or the like.

Further, it is preferable that an undercoating film and an intermediate coating film are formed as the substrate. As the electrodeposition paint for forming the undercoat film, a cationic type or an anion type can be used, but the cationic electrodeposition paint composition gives a laminated coating film having excellent corrosion resistance.

The above-mentioned intermediate coating film is used for concealing base defects, ensuring surface smoothness after top coating (improving appearance), and imparting coating film properties (impact resistance, chipping resistance, etc.). It is. To form the intermediate coating film, an intermediate coating material is used. The intermediate coating material contains various organic or inorganic coloring pigments, extender pigments, a film-forming resin, a curing agent, and the like.

Examples of the color pigment used in the intermediate coating composition include those described above. Further, flat pigments such as aluminum powder and graphite powder may be added. As a standard, a gray intermediate paint containing carbon black and titanium dioxide as main pigments is used. Further, a so-called color intermediate coating which is a combination of set gray and various color pigments may be used.

Examples of the film-forming resin used in the intermediate coating composition include those described above. From the viewpoint of pigment dispersibility and workability, a combination of an alkyd resin and / or a polyester resin and an amino resin is preferable.

The above-mentioned intermediate coating can be used in an uncured state after being applied onto a substrate on which an undercoat is formed. By setting the temperature to 180 ° C, preferably 120 ° C to 160 ° C, a cured coating film having a high degree of crosslinking can be obtained. 180 ° C
If it exceeds, the coating film becomes hard and brittle, and if it is less than 100 ° C.,
Insufficient curing. The curing time varies depending on the curing temperature, but is suitably from 120 ° C to 160 ° C for 10 to 30 minutes.

[0052]

FIG. 1 is a sectional view showing an example of a laminated coating film formed by the method of the present invention. An undercoating film 5 and an intermediate coating film 4 are formed on a substrate 6, and a color base coating film 3, a metallic base coating film 2, and a clear coating film 1 are formed thereon. The method for forming the undercoat 5 and the intermediate coat 4 on the substrate 6 may be any method known to those skilled in the art.

Next, on the base material 6 on which the undercoating film 5 and the intermediate coating film 4 are formed, first, a color base coating material is applied to form the color base coating film 3. When the above-mentioned color base paint is applied to an automobile body, in order to enhance the design, multi-stage painting by air electrostatic spray painting, preferably two-stage painting, or air electrostatic spray painting, commonly referred to as "electrostatic spray painting" The coating film can be formed by a coating method using a combination of a rotary atomization type electrostatic coating machine called “μμ (micro micro) bell”, “μ (micro) bell” or “metabell”.

The thickness of the coating film when applied with the color base coating in the present invention varies depending on the desired use, but in most cases, 10 to 40 μm is useful. If it exceeds 40 μm, the sharpness may deteriorate, or problems such as unevenness or flow may occur at the time of coating, and if it is less than 10 μm,
The base cannot be concealed and the film breaks. The color base coating may or may not be cured. When the color base coating film is cured after the application, the curing conditions may be the same as those described for the intermediate coating.

A metallic base paint and a clear paint are applied on the color base paint film to form a metallic base paint film 2 and a clear paint film 1. At this time, it is preferable to apply a clear coating on the metallic base coating film 2 without curing the coating.

The metallic base paint used for forming the metallic base coating film 2 can be applied by a rotary atomizing electrostatic coating machine such as a μμ bell, μ bell, etc. in the same manner as the color base paint. The dried film thickness of the coating film is set at 10 to 30 μm.

The clear coating film 1 applied after the formation of the metallic base coating film 2 is formed for smoothing and protecting unevenness and glare caused by the brilliant pigment contained in the metallic base coating film 2. Is done. Specifically, as a coating method, it is preferable to form a coating film by using a rotary atomizing electrostatic coating machine such as a μμ bell or μ bell described above.

The dry film thickness of the clear coating film formed by the clear coating is generally preferably about 10 to 70 μm, more preferably about 20 to 50 μm. 70
If it exceeds μm, inconveniences such as splashes and sagging may occur at the time of coating, and if it is less than 10 μm, the unevenness of the base cannot be hidden.

Thereafter, the coating film thus laminated is cured. The curing conditions include those described above. When the above-mentioned color base paint and metallic base paint are used as water-based paints, in order to obtain a good finished paint film, the paint film is formed after each formation.
It is desirable to preheat at 0 to 80 ° C for 2 to 10 minutes.

The film thickness of the multilayer coating film formed by the method of forming a multilayer coating film of the present invention plus the thicknesses of the undercoat film and the intermediate coating film is 30 to 300 μm in many cases. Preferably it is 50 to 250 μm. If it exceeds 300 μm, the film properties such as cooling and heating cycle will decrease,
If it is less than the above, the strength of the film itself is reduced.

[0061]

EXAMPLES The present invention will be described in detail with reference to specific examples, but the present invention is not limited to the following examples. In the following, “parts” means “parts by weight”.

Production Example 1 Production of Color Base Paint 1 Color base paint 1 was produced with the composition shown in Table 1 (parts by weight). Incidentally, the Munsell value of the color base coating film formed with this coating material was 5.0R2.7 / 7.0.

[0063]

[Table 1]

Production Example 2 Production of Metallic Base Paint 1 Red metallic base paint 1 was produced according to the formulation shown in Table 2. RT-355D and Raven 5000W3 were added to adjust the color tone of the paint. Those used in Table 2 are shown below. 98-4008RE: Red aluminum pigment manufactured by Toyo Aluminum Co., Ltd., average particle size 19 μm, solid content 51% by weight, Munsell value 4.5R5.0 / 12.0 Shinkasha Red Y-RT-759D: Red pigment manufactured by Ciba Specialty Chemicals , Munsell value 3R3.5 /
10.0 Perylene Maroon R-6436: Red pigment manufactured by Miles, Munsell value 5R2.5 / 7.5 RT-355D: Red pigment manufactured by Ciba Specialty Chemicals, Munsell value 7.5RP3.5 / 11.5 Alumina sienna: Merck mica, average particle size 18μ
m Iridion 7215WII: Mica manufactured by Merck, average particle size 19 μm Raven 5000W3: Black pigment manufactured by Columbia Thermosetting acrylic resin 1: Nippon Paint Co., Ltd., hydroxyl value 45, acid value 15, number average molecular weight 21000, solid content 50
% By weight Thermosetting acrylic resin 2: Nippon Paint Co., Ltd., hydroxyl value 95, acid value 20, number average molecular weight 4000, solid content 60% by weight Thermosetting polyester resin: Nippon Paint Co., Ltd., hydroxyl value 110, acid value 8 Melamine resin: Uban 20N60, butylated melamine resin manufactured by Mitsui Toatsu Co., solid content 60% by weight Crosslinked acrylic resin particles prepared by the following method were used. Using.

Production Example 3 Production of Crosslinkable Resin Particles In a reaction vessel equipped with a stirring and heating device, a thermometer, a nitrogen inlet tube, a cooling tube and a decanter, 213 parts by weight of bishydroxyethyltaurine, 208 parts by weight of neopentyl glycol, anhydrous 296 parts by weight of phthalic acid, 376 parts by weight of azelaic acid and 30 parts by weight of xylene were charged and heated to the reflux temperature. Here, water generated by the reaction was removed by azeotropic distillation with xylene. The temperature in the reaction system was raised to 210 over about 3 hours from the start of reflux, and the reaction was carried out with stirring and dehydration until the acid value corresponding to carboxylic acid in the resin solids reached 135 mgKOH / g.

After the temperature in the reaction system was cooled to 140 ° C., 500 parts by weight of “Kajura E10” (trade name, glycidyl versatate) manufactured by Shell Co., Ltd. were added to 30 parts by weight.
Dropped over minutes. Then, after stirring for about 2 hours, the reaction was terminated. Thereby, the acid value of the resin solid content is 55 m
gKOH / g and hydroxyl value of 91 mgKOH / g
And a zwitterionic group-containing polyester resin having a number average molecular weight of 1250 was obtained. 10 parts by weight of the obtained amphoteric group-containing polyester resin, 140 parts by weight of deionized water, 1 part by weight of dimethylethanolamine, 50 parts by weight of styrene and 50 parts by weight of ethylene glycol dimethacrylate are vigorously stirred in a stainless steel beaker. Thereby, a monomer suspension was prepared. Also, an initiator aqueous solution was separately prepared by mixing 0.5 parts by weight of azobiscyanovaleric acid, 40 parts by weight of deionized water, and 0.32 parts by weight of dimethylethanolamine.

A reaction vessel equipped with a stirring and heating device, a thermometer, a nitrogen inlet tube and a cooling tube was charged with 5 parts by weight of a zwitterionic group-containing polyester resin, 280 parts by weight of deionized water and 0.5 part by weight of dimethylethanolamine. To 80 ° C. Here, the previously prepared monomer suspension 251
Parts by weight and 40.82 parts by weight of the aqueous initiator solution at the same time
After the reaction was continued for 60 minutes, the reaction was terminated to obtain a crosslinkable resin particle emulsion.

The average particle size of the crosslinked resin particle emulsion was 55 nm as measured by a dynamic light scattering method. Xylene was added to this crosslinkable resin particle emulsion, and azeotropic distillation was performed under reduced pressure to remove water and replace the medium with xylene. Thus, a xylene solution of crosslinkable resin particles having a resin solid content of 25% by weight, which can function as a structural viscosity imparting agent, was obtained.

Production Example 4, Comparative Production Examples 1 and 2 Production of Metallic Base Coatings 2 to 4 Red metallic base coatings 2 to 4 were produced in the same manner as in Production Example 2 with the composition shown in Table 2.

[0070]

[Table 2]

Examples 1 and 2, Comparative Examples 1 and 2 Formation of Laminated Coating Film Thickness 0.8 cm, 20 cm × 30 c treated with zinc phosphate
m Dal steel sheet, cationic electrodeposition paint "Power Top U-
50 "(manufactured by Nippon Paint Co., Ltd.) was electrodeposited such that the dry film thickness became 20 μm, and baked at 160 ° C. for 30 minutes. Next, on the obtained electrodeposition coating film, a gray intermediate coating material “Olga P-2 Gray” (a polyester / melamine resin-based coating material manufactured by Nippon Paint Co., Ltd.) was applied with a dry film thickness of 30 μm.
And baked at 140 ° C. for 20 minutes to form a base coat.

On the obtained intermediate coating film, the color base paint of the above-mentioned production example was applied so that the dry film thickness became 30 μm.
The coating was performed by "Auto REA" (air electrostatic coating machine manufactured by Ransburg) on two stages at intervals of 2 minutes. After a 10 minute interval, baking was performed at 140 ° C. for 20 minutes. Further, the metallic base paints of the above-mentioned production examples shown in Table 3 were similarly electrostatically coated so that the dry film thickness became 15 μm. Next, after setting for 7 minutes, the clear coating material “Macflow O-13” was further wet-on-wet.
31 Clear "(acid / epoxy-curable acrylic resin-based paint manufactured by Nippon Paint Co., Ltd.) was subjected to rotary atomization electrostatic coating using a μμ bell so that the dry film thickness became 30 μm. 140
The coating was baked at 20 ° C. for 20 minutes to form a coating film for evaluation.

The Munsell value of the obtained laminated coating film was measured using a colorimeter “SM Color Computer SM-6- 6” manufactured by Suga Test Instruments Co., Ltd.
H (hue), V (lightness), and C (saturation) were measured using "1S-2B". The results are shown in Table 3.

The obtained coated plate was subjected to a weather resistance test using a sunshine weatherometer (manufactured by Suga Test Instruments; WEL-SUN-HC type) under the following conditions. Test conditions: voltage 50V, current 60A, humidity 50-60
% During irradiation for 60 minutes at a temperature of 45-47 ° C.
Water spray was repeated for 2,000 minutes for 2000 hours. The above-mentioned water is deionized water having a pH of 6-8 at 2000 ± 1.
It was used at a rate of 00 ml / min.

With respect to the coating film after the test, the gonio color difference was measured using a gonio color difference meter “512m-3” manufactured by Minolta. The gloss was measured using a gloss meter GM-26D (manufactured by Murakami Color Co., Ltd.). The results are shown in Table 3.

[0076]

[Table 3]

From the results shown in Table 3, the laminated coating film of Comparative Example 1 using the metallic base paint containing no colored aluminum pigment did not have a vivid color tone in Munsell display. The laminated coating film of Comparative Example 2 using the metallic base paint containing the colored aluminum pigment but not the auxiliary coloring pigment was a coating film of a vivid color immediately after the coating, but after the weather resistance test, both the gloss and the color difference were observed. Was inferior. On the other hand, the laminated coating films of Examples 1 and 2 using the metallic base paint containing the colored aluminum pigment and the auxiliary colored pigment maintained a vivid color tone in both gloss and color difference even after the weather resistance test.

[0078]

As described above, the coating composition of the present invention has the above-mentioned composition. Therefore, the laminated coating film obtained by using the coating composition as a metallic base coating does not show color jumps due to long-term outdoor use. It is a high degree.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a laminated coating film formed by a method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Clear coating film 2 Metallic coating film 3 Color base coating film 4 Intermediate coating film 5 Undercoat coating film 6 Substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 5/29 C09D 5/29 F-term (Reference) 4D075 AE12 BB26Z CA32 CB04 CB06 CB13 DA06 DA23 DA25 DB02 DB05 DB06 DB07 DB08 DB13 DB31 DC12 DC13 EA06 EA07 EA10 EA43 EB16 EB22 EB32 EB33 EB35 EB36 EB38 EB45 EC10 EC11 EC54 4F100 AA19A AB01B AB10A AK01A AK01C09 AK25 AK36 AK41 AT00B BA03 BA07 BA10 BA00ACA20A10A00 DD001 DG302 HA066 KA08 KA20 NA01 PB03 PB07 PC02

Claims (6)

[Claims] 1. A coating composition comprising, as a color pigment component, a colored aluminum pigment and an auxiliary color pigment, wherein the color aluminum pigment and the auxiliary color pigment have the same hue in a 10-color hue circle in Munsell display. A paint composition characterized in that the difference in chroma in Munsell display is 5 or less and the difference in lightness is 3 or less. 2. The coating composition according to claim 1, wherein the color aluminum pigment and the auxiliary color pigment have a difference of 3 or less in Munsell hue. 3. The coating composition according to claim 1, wherein the auxiliary coloring pigment is blended in an amount of 20 to 800 parts by weight, based on 100 parts by weight of the colored aluminum pigment in terms of solid content. Forming a color base coating film on the substrate; forming a metallic base coating film on the color base coating film, and forming a clear coating film thereon without curing the metallic base coating film; A step of curing the metallic base coating and the clear coating by heating, wherein the metallic base coating is a coating composition according to claim 1, 2 or 3. And a colored aluminum pigment in the metallic base coating film and the color base coating film, wherein the difference in the hue of the Munsell display is 3 or less. Forming method. 5. The method according to claim 4, wherein the color base coating film has a Munsell hue (H) of 2.5R to 10R. 6. A laminated coating film formed by the method according to claim 4 or 5.