JPH10330657A - Metallic coating material and formation of plural layered coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new metallic coating material without remarkable orientation unevenness of a metallic pigment and a method for forming plural layered coating films using the same. SOLUTION: This metallic coating material (A) contains metallic pigment covering the surface of aluminum flakes in black color in a degree not losing a glossy appearance. This method for forming plural layered coating films uses the metallic coating material A as a metallic coating material in forming plural layered coating films by coating metallic coating material and clear coating material. In forming plural layered coating films by coating colored coating material, metallic coating material and clear coating material in turn, the metallic coating material is used A as the metallic coating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel metallic paint in which unevenness in orientation of a metallic pigment is inconspicuous, and a method for forming a multilayer coating film using the same.

[0002]

2. Description of the Related Art Metallic paints using aluminum flakes as metallic pigments are already known and are often used for painting automotive exterior panels. In this metallic paint film, aluminum flame
The flakes are oriented almost parallel to the coating surface, and the flakes are hit by light rays and reflected to give a glittering glitter.

[0003] However, it is rare that all of the aluminum flakes are oriented parallel to the coated surface, and a portion of the same coated surface, whose orientation is disturbed, often causes uneven brightness. This causes the finished appearance to deteriorate.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel metallic paint in which, even if the orientation of aluminum flakes is partially disturbed on the same coated surface, the unevenness of glitter is not so noticeable. As a result of diligent research, the present inventors have found that the object can be achieved by using, as a metallic pigment, an aluminum flake coated with black to such an extent that the glitter does not disappear, thereby completing the present invention.

That is, the present invention provides a metallic paint characterized by containing a metallic pigment obtained by coating the surface of an aluminum flake with black to such an extent that the glitter does not disappear (hereinafter referred to as "paint of the present invention"). ).

Further, the present invention relates to a metallic paint (A)
And applying the clear paint (B) to form a multilayer paint film, wherein the paint of the present invention is used as the metallic paint (A) (hereinafter referred to as the “method of the present invention”). 1 ").

Further, the present invention relates to a method of forming a multilayer coating film by sequentially applying a colored paint (C), a metallic paint (A) and a clear paint (B) to form a multi-layer coating film. There is provided a method for forming a multilayer coating film (hereinafter, referred to as "method 2 of the present invention") using an inventive paint.

The paint of the present invention and the methods 1 and 2 of the present invention will be described in more detail.

[0009] Paint of the present invention : A metallic paint characterized by containing a metallic pigment obtained by coating the surface of an aluminum flake with black to such an extent that the glitter does not disappear.

The metallic pigment used in the paint of the present invention is an aluminum flake, and is a pigment whose surface is coated in black to such an extent that the glitter does not disappear. Specifically, aluminum flakes are non-free
The fining type is preferably flaky metal aluminum and has a thickness of 0.1 to 1.0 μm, particularly 0.2 μm.
0.5 μm, longitudinal dimension 2-50 μm, especially 10
Suitably, it is 30 μm. Then, the surface of the flake is coated with a black coloring agent such as carbon black to such an extent that the glitter does not disappear. This coating is
For example, it can be obtained by uniformly mixing a black colorant with a usual coating resin, mixing aluminum flakes into the mixture, dispersing both components, and then drying the particles in the form of aluminum flakes.

It is preferable to coat the surface of the aluminum flakes with a metal oxide such as titanium oxide before or after the aluminum flakes are coated with black, since the pearl-like or light interference effect is exhibited. .

The paint of the present invention comprises a resin component, the above-mentioned black-coated aluminum flake and a solvent as main components, and further contains a coloring pigment, an extender pigment and other paint additives as required. It is a liquid paint.

As the resin component, a thermosetting resin composition is preferable. Specifically, a base resin such as an acrylic resin, a polyester resin, an alkyd resin, or a urethane resin having a crosslinkable functional group is used as a melamine resin, a urea resin, or a polyisocyanate. And those used in combination with a crosslinking agent such as a compound (including a block compound).

In the paint of the present invention, the amount of the black-coated aluminum flake is preferably 2 to 40 parts by weight, more preferably 5 to 20 parts by weight, per 100 parts by weight of the solids of the resin composition.

The coating composition of the present invention is prepared by mixing and dispersing the resin composition and the black-coated aluminum flake in a solvent such as an organic solvent or water, and has a solid content of 20 to 60% by weight at the time of coating. , Preferably 25 to 50
By weight, the viscosity was 10 to 30 seconds / Ford cup # 4 /
It is preferable to adjust the temperature to 20 ° C.

The paint of the present invention may be applied directly to an object to be coated such as a metal or plastic automobile outer panel, but usually, an undercoat (such as a cationic electrodeposition paint) is applied to these objects. ) Or an intermediate coating is preferably applied in advance and applied to the object to be cured. The coating can be performed using an air spray, an airless spray or an electrostatic coating machine, and the film thickness is preferably, for example, 15 μm or more and 20 to 70 μm based on the cured coating film. The coating is applied at a temperature of about 100 to
When heated for 40 minutes, crosslinking and curing can be performed.

In the metallic coating film of the paint of the present invention, the orientation of the aluminum flakes is almost the same as the conventional one, and most of the aluminum flakes are oriented parallel to the coating surface. In some cases, the portions were visually disturbed, but the unevenness of glitter between the two (metallic unevenness) was almost inconspicuous in appearance. In other words, the portions where the aluminum flakes are oriented in parallel and the portions where the aluminum flakes are not parallel are both coating films based on black tint, and the former shows a metallic tone in which glitter is suppressed by this black look, while the latter shows a metallic tone. Although the metallic feeling is even lower, it has a black tint, and as a result, both parts are based on black tint and show a suppressed glitter, so the difference is less clear than before, Up,
Almost inconspicuous as metallic unevenness.

Method 1 of the present invention : In coating a metallic paint (A) and a clear paint (B) to form a multilayer coating film, the paint of the present invention is used as the metallic paint (A). This is a multilayer coating film forming method.

The metallic paint (A) used in the method 1 of the present invention is a paint selected from the above-mentioned paints of the present invention.

The clear paint (B) is a paint which is applied to an uncured or cross-linked cured surface of the metallic paint (A), and contains a resin component and a solvent as main components, and further comprises A liquid paint which forms a colorless or colored transparent coating film containing a coloring pigment and other paint additives to such an extent that the transparency of the coating film is not impaired.

The resin component used in the clear paint (B) is preferably a thermosetting resin composition. Specifically, a base resin such as an acrylic resin, a polyester resin, an alkyd resin, or a urethane resin having a crosslinkable functional group is used. Those used in combination with a crosslinking agent such as a melamine resin, a urea resin and a polyisocyanate compound (including a block body) can be mentioned, and as the solvent, an organic solvent and / or water can be used.

In the method 1 of the present invention, the metallic paint (A) is applied directly to an object to be coated such as a metal or plastic automobile outer panel, or to an undercoat (for example, a cationic electrodeposition paint or the like). ) Or intermediate paint (can be omitted).

The metallic coating (A) has a solid content of 20 when coated with a solvent such as an organic solvent or water.
-60% by weight, preferably 25-50% by weight, and a viscosity of 1
0 to 30 seconds / Ford cup # 4/20 ° C., adjusted to 15 μm or more based on the cured coating film by using an air spray, airless spray or electrostatic coating machine.
It is preferable to apply the coating to a thickness in the range of 70 μm.
The coating is applied at a temperature of about 100 to about 170 ° C for 10 to 40.
When heated for a minute, it can be cross-linked and cured.

Further, a clear paint (B) is applied to the cured or uncured metallic painted surface. The clear paint (B) has a solids content of 20 to 60% by weight, preferably 25 to 60% by weight, when coated with a solvent such as an organic solvent or water.
50% by weight, viscosity of 10 to 30 seconds / Food cup # 4
/ 20 ° C., and it is preferable to apply a film having a thickness of 15 μm or more and 20 to 70 μm based on the cured coating film using an air spray, an airless spray or an electrostatic coating machine. . The coating is from about 100 to about 17
When heated at a temperature of 0 ° C. for 10 to 40 minutes, crosslinking and curing can be performed.

The method 1 of the present invention is a method of forming a multilayer coating film by applying the metallic coating material (A) and the clear coating material (B) as described above. This can be achieved by a coating method using a two-coat one-bake system (2C1B) or a two-coat two-bake system (2C2B) in which crosslinking and curing are performed separately.

Method 2 of the present invention : In forming a multilayer coating film by sequentially applying the colored paint (C), the metallic paint (A) and the clear paint (B), the present invention uses the metallic paint (A) as the metallic paint (A). This is a method for forming a multilayer coating film using a paint.

In the method 2 of the present invention, the above-mentioned metallic paint (A) and clear paint (B) can be used.

The coloring paint (C) contains a resin component, a coloring pigment, and a solvent as essential components, and further contains, if necessary, an extender pigment and other paint additives. A paint is suitable, and its color tone is not limited at all, and may be any of a chromatic color and an achromatic color.

As a resin component in the coating material, a thermosetting resin composition is preferable. Specifically, a base resin such as an acrylic resin, a polyester resin, an alkyd resin or a urethane resin having a crosslinkable functional group is used as a resin component. Examples thereof include those used in combination with a crosslinking agent such as a resin and a polyisocyanate compound (including a block body). These are dissolved or dispersed in a solvent such as an organic solvent and / or water.

Examples of coloring pigments include titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chrome ero, chromium oxide, prussian blue, cobalt blue, azo pigments, phthalocyanine pigments,
Solid pigments such as quinacridone pigments, isoindoline pigments, sullen pigments and perylene pigments; metallic pigments such as flaky aluminum, mica, mica coated with metal oxide, and mica iron oxide; You.

In the method 2 of the present invention, the colored paint (C)
Can be applied directly to the object to be coated, such as a metal or plastic automobile outer panel, but usually, such an object is coated with an undercoat (for example, a cationic electrodeposition paint) or an intermediate coat (omitted). It is preferable to apply the composition to an object to be coated which is previously coated and cured.

The colored paint (C) is coated with a solvent such as an organic solvent or water to have a solid content of 20 to 60% by weight, preferably 25 to 50% by weight, and a viscosity of 10 to 30 seconds / form. Cup # 4/20 ° C., and apply to these objects using an air spray, an airless spray or an electrostatic coating machine or the like, based on the cured coating film, in a range of 15 μm or more and 20 to 70 μm. It is preferable to apply the coating to the inside thickness. The coating is applied at a temperature of about 100 to about 170 ° C.
When heated for 0 to 40 minutes, crosslinking and curing can be performed.

Next, the coating of the colored coating (C) is heated and cured, or in an uncured state, the metallic coating (A) is applied to the coated surface.

The metallic paint (A) has an organic solvent or a solvent such as water, and has a solid content of 20 to 6 at the time of coating.
0% by weight, preferably 25 to 50% by weight, and a viscosity of 10 to 10% by weight.
Adjust to 30 seconds / Ford cup # 4/20 ° C,
Using an air spray, an airless spray, or an electrostatic coating machine, based on the cured coating film, 15 μm or more, 20 to 7
It is preferable to apply the film on the coating surface of the heat-cured or uncured colored paint (C) so as to have a film thickness in the range of 0 μm. The coating can be cross-linked and cured by heating at a temperature of about 100 to about 170C for 10 to 40 minutes.

Further, a clear paint (B) is applied to the cured or uncured metallic painted surface. The clear paint (B) has a solids content of 20 to 60% by weight, preferably 25 to 60% by weight, when coated with a solvent such as an organic solvent or water.
50% by weight, viscosity of 10 to 30 seconds / Food cup # 4
/ 20 ° C., and it is preferable to apply a film having a thickness of 15 μm or more and 20 to 70 μm based on the cured coating film using an air spray, an airless spray or an electrostatic coating machine. . The coating is from about 100 to about 17
When heated at a temperature of 0 ° C. for 10 to 40 minutes, crosslinking and curing can be performed.

As described above, the method 2 of the present invention comprises a colored paint (C), a metallic paint (A) and a clear paint (B).
Is applied to form a multi-layer coating film, a three-coat one-bake system (2C1B) in which these coating films are simultaneously cross-linked and cured by heating, and a three-coat two-bake system in which they are separately cross-linked and cured. (3C2B) or 3-coat 3-bake method (3C3B)
This can be achieved by the coating method according to B).

In the methods 1 and 2 of the present invention, any one or all of the above-mentioned leaving at room temperature in the coating step is performed for about 5 hours.
Pre-drying at a temperature of 0 to about 100 ° C can be substituted. This preliminary drying is performed when the gel fraction of each coating film is 60% by weight.
It is preferable to carry out the procedure to the extent that the following is achieved.

[0038]

[Effects of the present invention]

1) Aluminum flame of the metallic coating film of the paint of the present invention
There is almost no difference in the orientation of the metal compared to the conventional one, and even if metallic unevenness occurs, it is possible to finish it almost inconspicuously.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. Parts and percentages are by weight unless otherwise specified.

1. Sample 1) Coated object Degreasing and zinc phosphate treated steel sheet (JIS G31
41, a 400 × 300 × 0.8 mm cationic electrodeposition paint (“Electron 9400HB”, manufactured by Kansai Paint Co., Ltd.), a block polyisocyanate compound as a curing agent for epoxy resin polyamine-based cationic resin Is applied by a conventional method so as to have a film thickness of 20 μm (as a cured coating film), and is heated at 170 ° C. for 20 minutes for crosslinking and curing. ("LuGabeque middle coating gray", Kansai Paint Co., Ltd.)
(Trade name, polyester resin / melamine resin type, organic solvent type) was applied so as to have a thickness of 30 μm (as a cured coating film), and was heated at 140 ° C. for 30 minutes to be crosslinked and cured.

2) Clear paint (B) "Lugagabe clear", manufactured by Kansai Paint Co., Ltd., trade name, acrylic resin / amino resin type, organic solvent type. Solid content at coating: 42%, viscosity at coating: 21 seconds / Ford cup # 4/20 ° C.

3) Colored paint (C) "Magiclon TB300", manufactured by Kansai Paint Co., Ltd., trade name, acrylic resin / amino resin type, organic solvent type. Solid content 20% at coating, viscosity 13 sec at coating / Food cup # 4/20 ° C.

2. Examples and Comparative Examples (Paints of the Present Invention) The components shown in Table 1 were combined (solid content) in the same table.
The paint of the present invention (metallic paint A) was prepared by mixing according to the procedure described in Example 1. As a solvent, a mixed solvent of ethyl acetate / toluene / solvesso 150 = 50/30/20 (weight ratio) was used.

[0044]

[Table 1]

* 1) Acrylic resin: hydroxyl value 100, number average molecular weight 20,000 * 2) Melamine resin: methyl / butyl mixed etherified melamine resin * 3) Coated aluminum flake: 100 parts of aluminum flake having a particle size of 18 μm Per 10 parts of carbon black. * 4) Aluminum flake: manufactured by Toyo Aluminum Co., Ltd., trade name "AL7620NS".

3. Examples and Comparative Examples Method 1 of the Invention: Metallic paints (A1) to (A4) were applied to the intermediate coating surface of the article to be coated using a REA gun at a temperature in the booth of 20 ° C. and a humidity of 75%. The film thickness is 10 μm (as a cured coating). Then, this metallic paint (A
The clear coating (B) was applied to the uncured coating surface of (1) to (A4) using a mini-bell type rotary electrostatic coating machine at a bus temperature of 20
It painted at 75 degreeC and 75% of humidity. The coating thickness is 25 μm (as a cured coating). Leave it indoors for 3 minutes, then 140
By heating at 30 ° C. for 30 minutes, the multilayer coating film composed of the metallic coating film and the clear coating film was simultaneously cross-linked and cured.

Method 2 of the present invention: The colored coating (C) was applied to the intermediate coating surface of the article to be coated by using a mini-bell type rotary electrostatic coating machine.
The coating was carried out at a temperature of 20 ° C. and a humidity of 75%. The coating thickness is 1
5 μm (as a cured coating). Metallic paints (A1) to (A4) are applied to the uncured coating surface of the colored base paint.
Was coated at a temperature in the booth of 20 ° C. and a humidity of 75%. The film thickness is 4-5 μm (as a cured coating). Thereafter, the clear paint (B) was applied to the uncured coating surface of the metallic paint by using a mini-bell type rotary electrostatic coater at a temperature within the booth of 20 mm.
It painted at 75 degreeC and 75% of humidity. The coating thickness is 25 μm (as a cured coating). After leaving it indoors for 3 minutes, it was heated at 140 ° C. for 30 minutes in a hot air circulating drying oven to simultaneously cross-link and cure the multilayer coating film composed of the colored coating film, the metallic coating film, and the clear coating film.

4. Performance Test Results Table 2 shows the coating process of the paint and the performance test results of the obtained multilayer coating film.

[0049]

[Table 2]

The metallic feeling is a result of visually determining the degree of metallic unevenness of the obtained multilayer coating film. ○ indicates that metallic unevenness is hardly visible, Δ indicates that metallic unevenness is visible, and X indicates that metallic unevenness is clearly visible.

Claims (4)

[Claims] (1) A metallic paint characterized by containing a metallic pigment obtained by coating the surface of an aluminum flake with black to such an extent that the glitter does not disappear. 2. The method according to claim 1, wherein the metallic paint (A) and the clear paint (B) are applied to form a multilayer coating film, wherein the metallic paint according to claim 1 is used as the metallic paint (A). Multi-layer coating film forming method. 3. The metallic paint (A) according to claim 1, wherein the colored paint (C), the metallic paint (A) and the clear paint (B) are sequentially applied to form a multilayer paint film. A method for forming a multilayer coating film, comprising using a metallic paint. 4. The method according to claim 1, wherein the object to be coated is an automobile body.