JP2000176364A - Dual-layer film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strengthen the flip-flop properties and improve the design properties based on the light interference by applying a metallic coating material containing aluminum flakes of specified particle diameter and a color pigment and then applying a light interferential coating material containing a light interferential pigment and a color pigment. SOLUTION: A metallic coating material containing aluminum flakes of 10-20 μm particle diameter and a color pigment is applied on a material to be coated, and then a light interferential coating material containing a light interferential pigment and a color pigment is applied on a coated face. The tone of the color pigment in the metallic coating material is of similar family of the tone of the light interferential coating material. Also the metallic coating material, the light interferential coating material and a clear coating are applied successively on the material to be coated. The material to be coated is defined as outside plate sections of a car body. The flip-flop properties are strengthened by the high coloring degree and color mottles are eliminated to finish into the uniform hue by the arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a light interference multilayer coating film having excellent glitter and flip-flop properties.

[0002]

2. Description of the Related Art It is already known to apply an optical interference paint to a solid color surface to finish it as an optical interference coating. However, there is a defect that the flip-flop property is weak and the design property based on the optical interference cannot be sufficiently exhibited.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to enhance the flip-flop property of a multilayer coating film using a light interference paint and improve the design property based on light interference. The feature is that instead of the conventional solid color paint, a metallic paint containing a large particle size aluminum flake is used, and a similar color pigment is used for these metallic paint and light interference paint. It has been found that the above objects can be achieved by adding each of them, and that a vivid color tone can be achieved, and the present invention has been completed.

That is, according to the present invention, a particle having a particle size of 10
Applying a metallic paint (A) containing aluminum flakes and color pigments of .about.20 .mu.m, and then applying a light interference paint (B) containing a light interference pigment and a color pigment on the coated surface. The present invention also relates to a method for forming a multi-layer coating film characterized by the present invention, and the present invention further includes a method for forming a multi-layer coating film formed by applying a clear coating (C) on the coated surface of the light interference coating (B). are doing.

Hereinafter, the method for forming a multilayer coating film according to the present invention will be described in detail.

[0006] article to be coated: to form a multilayer coating film of the present invention, an object to be coated etc. metallic coating (A) is coated, and for example, metal or plastic body outer panel of an automobile It is preferable to apply an undercoat (for example, a cationic electrodeposition paint) or an intermediate coat (can be omitted) or the like in advance, and to cure the coating.

[0007] The electrodeposition paint is an undercoat paint applied to a conductive substrate, and any of a cationic type and an anionic type can be used, but a cationic type having excellent corrosion resistance is preferable.

As the cationic electrodeposition coating material, a known one obtained by mixing a pigment or various additives as necessary with an aqueous solution or aqueous dispersion of a salt of a cationic polymer compound can be used. For example, examples of the cationic polymer compound include those obtained by modifying an acrylic resin or an epoxy resin with an amino compound or the like to introduce a cationic group, and neutralizing this with an organic acid or an inorganic acid to form an aqueous solution or It can be made into an aqueous dispersion. Further, a block polyisocyanate compound, an alicyclic epoxy resin or the like can be suitably used as a crosslinking agent. Immerse the conductive coating material as a cathode in a cationic electrodeposition bath, apply electricity under normal conditions and apply electrodeposition coating,
The film thickness is preferably 10 to 30 μm based on the cured coating film, and the film can be crosslinked and cured by heating at 140 to 200 ° C. for 10 to 40 minutes.

[0009] The intermediate coating composition is to be applied to the undercoating surface. A liquid composition comprising a resin composition and a solvent as main components and, if necessary, a coloring pigment, an extender pigment and additives is used. Smoothness, sharpness,
Suitable for improving glossiness. Acrylic resin having a crosslinkable functional group such as a hydroxyl group as a resin composition,
A composition in which a crosslinking resin such as a melamine resin, a urea resin, or a polyisocyanate compound (including a block body) is blended with a base resin such as a polyester resin or an alkyd resin is exemplified. Organic solvents and / or water can be used as solvents. This intermediate coating is applied to the cured or uncured undercoating surface by electrostatic coating, air spraying, airless spraying or the like to form a cured coating film having a thickness of 10 to 50 μm.
Crosslinking and curing are performed by heating at 00 to 170 ° C for 10 to 40 minutes.

Metallic paint (A) : particle size of 10 to 20
A paint containing aluminum flakes and coloring pigments having a thickness of .mu.m, capable of forming a glittering glittering coating film, and is applied to an object to be coated prior to the light interference paint (B).

The metallic paint (A) contains a resin composition, aluminum flakes having a particle size of 10 to 20 μm, a coloring pigment, and a solvent as essential components. If necessary, an extender pigment, an antisettling agent, and an additive for a paint are added. A thermosetting liquid coating material containing an agent or the like is suitable.

The resin composition is preferably a thermosetting type,
For example, a base resin such as an acrylic resin, a polyester resin, an alkyd resin, and a urethane resin having a crosslinkable functional group such as a hydroxyl group, and a crosslinker such as a melamine resin, a urea resin, and a polyisocyanate compound (including a block body). These may be used in combination, and these may be used by dissolving or dispersing in a solvent such as an organic solvent and / or water. The ratio of the base resin to the crosslinking agent in the resin composition is 50 to 90% for the former and 50 for the latter based on the total weight of both components.
Within the range of 10% to 10%.

The aluminum flake is a brilliant scaly pigment containing metallic aluminum as a main component, and has a particle size of 10 to 20 μm, particularly 12 to 18 μm, and a thickness of 0.1 to 0.1 μm.
Those having a shape factor (aspect ratio) of 5 μm and an average particle diameter divided by the thickness within a range of 2 to 200 are suitable, and any of a leafing type or a non-leafing type can be used. The ratio of these aluminum flakes is 5 to 25 per 100 parts by weight (solid content) of the resin composition.
A range of parts by weight is respectively suitable. If the particle size of the aluminum flakes is smaller than 10 μm, the brilliant feeling in the highlight portion is reduced.

As the color pigment, for example, titanium oxide,
Inorganic such as zinc white, carbon black, cadmium red, molybdenum red, chrome ero, chromium oxide, prussian bull, cobalt bull, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline pigment, sulene pigment and perylene pigment And organic solid pigments. These compounding amounts may be within a range that does not decrease the glitter of the single coating film of the metallic paint (A) and that ensures the desired hiding property.

By using the aluminum flake and the coloring pigment together, the coating film of the metallic paint (A) itself can be colored other than the silver color, and the design feeling can be improved.

Examples of the solvent include an organic solvent and water.
As the organic solvent, a general coating solvent such as a hydrocarbon type, an ester type, an alcohol type, a ketone type and an ether type can be used.

The metallic paint (A) preferably has a single coating film which can completely hide the color tone of the base (coated surface, undercoated surface or intermediate coated surface). Therefore, it is preferable that the undercoat concealment film thickness of the single coating film is equal to or smaller than the coating film thickness.

The color tone of the single coating film of the metallic paint (A) is a chromatic or achromatic metallic tone.

The metallic paint (A) is used for 10 to 25 seconds /
Adjust the viscosity of FOOD CUP # 4/20 ° C and apply directly or directly to metal or plastic objects such as automobile outer panels by electrostatic coating, air spray, airless spray, etc. It is preferable to apply an undercoat (for example, a cationic electrodeposition paint) or an intermediate coat (optional) to the substrate, and apply it to a cured object to a thickness of 5 to 25 μm based on the cured coating film. . Such a metallic coating,
Crosslinking and curing can be performed by heating at a temperature of about 100 to about 200 ° C for 10 to 40 minutes.

A light interference coating (B) is applied to the cured or uncured coating surface of the metallic coating (A).

Light interference paint (B) : a light interference paint containing a light interference pigment and a color pigment, which is applied to the cured or uncured surface of the metallic paint (A). , A liquid paint obtained by dissolving and dispersing a resin composition, a light interference pigment, and a color pigment in a solvent, and the single coating film exhibits a colored light interference pattern, has a low base concealment property, and has a low undercoat layer. The metallic feeling of the coating film of the metallic paint (A) adjacent to the metallic paint can be seen through.

In the light interference paint (B), by using a color pigment together with the light interference pigment, it is possible to finish the color with high chroma.

Further, the color tone of the color pigment contained in the metallic paint (A) is made similar to the color tone of the color pigment contained in the light interference paint (B), so that the thickness of the light interference paint (B) is increased. The color appearance does not occur even if the value fluctuates, and the finished appearance is improved. Here, similar colors may be within a range included in the same hue group.

Examples of the resin composition in the light interference paint (B) include amino resins such as melamine resins and urea resins on base resins such as acrylic resins, polyester resins and alkyd resins having a crosslinkable functional group such as a hydroxyl group. (Block) A thermosetting composition containing a crosslinking agent such as polyisocyanate is included.

The light interference pigment is a scaly particle pigment having a light interference effect. Examples of the light interference pigment include mica, mica coated with a metal oxide such as titanium oxide and iron oxide, and color pigments. The average particle size in the longitudinal direction is preferably 5 to 50 μm, particularly preferably 10 to 40 μm, and the compounding amount is 100 parts by weight (solid content) of the resin composition.
The range is preferably 1 to 25 parts by weight, particularly preferably 3 to 20 parts by weight.

The light interference paint (B) is obtained by mixing the above components and dispersing them in a solvent such as an organic solvent and / or water, and has a coating film hiding power of 50 μm or Preferably, the coating is crosslinked and cured by heating at 100 to 170 ° C for 10 to 40 minutes.

The light interference coating (B) is formed by applying an electrostatic coating to the cured or cured coating surface of the metallic coating (A).
It is applied by an air spray or an airless spray so as to be thinner than the concealing film thickness.
Crosslink and cure by heating at 10 ° C for 10 to 40 minutes. Even when the light interference paint (B) is applied to the cured surface of the metallic paint (A), the two paint films do not mix.

The multi-layer coating film of the present invention comprises the metallic coating (A) and the light interference coating (B) in two coats as described above.
Bake method (2C1B) or 2-coat 2-bake method (2
This can be achieved by coating with C2B), and further includes a multilayer coating film obtained by coating the cured or uncured coating surface of the light interference coating (B) with the clear coating (C).

Clear paint (C) : A liquid composition which is applied to the coated surface of the light interference paint (B) and forms a colorless or colored transparent coating film obtained by mixing a resin composition and a solvent. .

The resin composition includes, for example, an acrylic resin having a crosslinkable functional group such as a hydroxyl group, a polyester resin,
Examples of the composition include a base resin such as an alkyd resin and a crosslinking resin such as an amino resin such as a melamine resin and a urea resin and a polyisocyanate. Further, JP-A-62-84137, JP-A-62-87288, JP-A-1-39653, and JP-A-2-4577.
JP, JP-A-1-39653, JP-A-2-4
577, JP-A-1-39653, JP-A-2
Thermosetting resin compositions which do not require the use of the amino resin as a crosslinking agent described in JP-A-4457, JP-A-1-39653, JP-A-2-4577) and the like are also preferably used. it can. As the solvent, an organic solvent and / or water can be used. The solvent is prepared by dissolving or dispersing the resin composition in the solvent. The clear paint (C) may contain a coloring pigment, a metallic pigment, a light interference pigment, an ultraviolet absorber and the like to such an extent that transparency is not impaired.

The clear coating (C) is applied to the cured or uncured coating surface of the light interference coating (B) by electrostatic coating, air spraying, airless spraying, or the like, based on the cured coating film. It is preferable to apply the coating so as to have a thickness of 50 μm.

The multilayer coating film according to the present invention comprises a metallic coating (A), a light interference coating (B) and a clear coating (C).
It can also be obtained by painting using a coat 1 bake method (3C1B), a 3 coat 2 bake method (3C2B), and a 3 coat 3 bake method (3C3B). The cross-linking and curing of a single-layer or multi-layer coating in these coating methods is 10
It is performed by heating at 0 to 180 ° C. for 10 to 40 minutes.

[0033]

The multilayer coating film of the present invention is composed of a metallic coating film containing a color pigment in the lower layer and a light interference coating film containing the color pigment in the upper layer. As it reaches the metallic coating and is reflected from it and passes through the light interference coating again, the flip-flop property becomes stronger, and since both coatings contain coloring pigments, the color is finished to a high chroma hue. In addition, by making the two paints have similar colors, it is possible to obtain an effect such that color blemishes are eliminated and a uniform hue can be obtained.

[0034]

Embodiments of the present invention will be described below. All parts and percentages are based on weight, and the thickness of the coating film is for the cured coating film.

1. Sample 1) Coated object Degreasing and zinc phosphate treated steel sheet (JIS G314
1, a size of 400 × 300 × 0.8 mm, a cationic electrodeposition paint (“ELECRON 9400HB”, manufactured by Kansai Paint Co., Ltd., trade name, epoxy resin polyamine-based cationic resin, block polyisocyanate as a curing agent The compound containing the compound is electrodeposited by a conventional method so as to have a film thickness of 20 μm, cured by heating at 170 ° C. for 20 minutes, and then coated on the coated surface with an intermediate coating (“Lugagabe middle coating”). White ”, manufactured by Kansai Paint Co., Ltd., trade name, polyester resin / melamine resin type, organic solvent type), coated to a thickness of 30μ, and cured by heating at 140 ° C for 30 minutes.
It was an object to be coated.

2) Metallic paint (A) (A-1): 100 parts (solid content) of a resin composition comprising a hydroxyl group-containing acrylic resin (Note 1) and a melamine resin (Note 2), aluminum flake (Note) 3) An organic solvent-type coating composition comprising 10 parts of phthalocyanine screen (trade name of "Green S" manufactured by Dainippon Ink and Chemicals, Inc.). Base concealment film thickness 15 μm.

Note 1) Acrylic resin: hydroxyl value 110, number average molecular weight 25000 Note 2) Melamine resin: Butyl etherified melamine resin Note 3) Aluminum flake: Toyo Aluminum Co., non-leafing aluminum flake, granules Diameter 12-18μ
m, thickness 1-2 μm, aspect ratio 100.

(A-2): A resin composition 10 comprising a hydroxyl group-containing acrylic resin (Note 1) and a melamine resin (Note 2)
Aluminum flake per 0 parts (solid content) (Note 3)
15 parts, phthalocyanine lean (“Green S”) 5
Organic solvent-type paint with blended parts. Base concealment film thickness 15μ
m.

3) Light interference coating (B) (B-1): 70 parts of hydroxyl-containing acrylic resin (Note 6),
30 parts of butylated melamine resin (Note 7), titanium oxide-coated scaly mica (optical interference pigment, 15 to 20 μm in longitudinal direction, trade name “Iliodin 103R”, trade name, manufactured by Merck Ltd.) 1
Organic solvent-type paint containing 0 parts and 2 parts of phthalocyanine line ("Green S"). Underlayer concealed film thickness 100μ
m or more.

Note 6) Hydroxyl group-containing acrylic resin: hydroxyl value 100, number average molecular weight 20,000.

Note 7) Butylated melamine resin: A mixed methyl / butyl etherified melamine resin.

(B-2): The resin solid content of an aqueous emulsion of a resin composition comprising 65 parts of a hydroxyl group-containing acrylic resin (Note 8), 15 parts of a urethane resin (Note 9) and 20 parts of a melamine resin (Note 10) is 100. Per part by weight (solid content)
Titanium oxide-coated scaly mica (above “Iriodin 103
R ") and 15 parts of phthalocyanine lean (" Green S "). Underlayer concealed film thickness of 100 μm or more.

Note 8) Hydroxyl-containing acrylic resin: An emulsion having an average particle size of 0.1 μm and a hydroxyl value of 35. Neutralized with dimethylethanolamine.

Note 9) Urethane resin: water-extended emulsion. Neutralized with triethylamine.

Note 10) Melamine resin: "U-Van 28S
E "(manufactured by Mitsui Toatsu Chemicals, Inc., trade name, hydrophobic melamine resin).

4) Clear paint (C) (C-1): "Lugabek clear", manufactured by Kansai Paint Co., Ltd., trade name, acrylic resin / amino resin type, organic solvent type.

2. Example The metallic coating material (A) was applied to the intermediate coating cured surface of the object to be coated using a mini-bell type rotary electrostatic coating machine at a temperature of 20 ° C and a humidity of 7 ° C.
It was painted at 5% and left at room temperature for 3 minutes. The coating thickness is 15
μm. Then, on this uncured metallic coating surface,
The light interference paint (B) was prepared using a REA gun at a temperature of 20 ° C.
It was painted at a humidity of 75% and left at room temperature for 3 minutes. The film thickness is 1
5 to 18 μm. Thereafter, the coating was heated at 140 ° C. for 30 minutes to crosslink and cure both the metallic coating and the light interference coating at the same time.

Further, the metallic paint (A) and the light interference paint (B) were applied as described above, and the system coated with (B-1) was allowed to stand at room temperature for 3 minutes, and then (B-2) After preheating at 80 ° C. for 10 minutes, the uncured coating surface of the light interference coating (B) is coated with the clear coating (C) using a mini-bell type rotary electrostatic coating machine at a temperature of 20 ° C. , Humidity 75
% Painted. The coating thickness is 40 μm. 10 indoors
Then, the mixture was heated at 140 ° C. for 30 minutes to simultaneously crosslink and cure the three-layer coating film composed of the metallic coating film, the light interference coating film and the clear coating material.

Table 1 shows the coating process of the metallic paint (A), the light interference paint (B) and the clear paint (C), and the performance test results of the obtained multilayer coating film.

[0050]

[Table 1]

The test method is as follows.

F / F property: The result of visual observation of flip-flop property. ○ indicates that the color tone is clearly changed depending on the observation angle, and the design is excellent. △ indicates that the color tone is little changed depending on the observation angle. Poor, × indicates no change in color tone depending on the viewing angle, indicating poor design.

Glossiness: This is a result of visually evaluating the glossiness of the coated surface. ○ indicates good glossiness, Δ indicates slightly poor glossiness, and X indicates slightly poor glossiness.

Claims (4)

[Claims] 1. An object to be coated is coated with a metallic paint (A) containing an aluminum flake having a particle size of 10 to 20 .mu.m and a coloring pigment, and then containing a light interference pigment and a coloring pigment on the coated surface. A multi-layer coating film forming method, which comprises applying a light interference paint (B). 2. The method according to claim 1, wherein the color tone of the color pigment of the metallic paint (A) is the same as the color tone of the color pigment of the light interference paint (B). 3. A method for forming a multilayer coating film, comprising sequentially applying the metallic paint (A), the light interference paint (B) and the clear paint (C) on an object to be coated. 4. The method according to claim 1, wherein the object to be coated is an outer plate of an automobile body.