JP2001327916A - Method for forming laminated pearl coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated pearl coating film excellent in transparent appearance by controlling yellowing, which occurs in a coating film containing a mica pigment, when seen from a shade position by using silica flakes coated with titanium dioxide. SOLUTION: In a method for forming the laminated pearl coating film which includes a process in which a color base coating film is formed on a base material on which an under coat film and an intermediate coat film are formed, a process in which a mica base coating film is formed on the color base coating film, and a clear coating film is formed on the mica base coating film without curing the mica base coating film, and a process in which the mica-base coating film and the clear coating film are cured by heating, the brightness of the color base coating film is 20-60 in L-value, and the mica base coating which forms the mica base coating film contains 1-10% of pigment concentration (PWC) of the silica flakes coated with titanium dioxide.

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 pearl coating having a pearl-like appearance, and more particularly to a method for forming a laminated pearl coating comprising a plurality of laminated coatings.

[0002]

2. Description of the Related Art In order to cope with the need for a multi-color top coat and to meet the needs, pearl coating films formed by paints containing scale-like mica pigments are increasing year by year. For example, in JP-A-11-114489, a color base paint,
A method has been proposed in which a base paint and a clear paint containing an interference mica pigment are sequentially applied to form a laminated coating film.

Further, Japanese Patent Application Laid-Open No. Hei 9-508172 discloses a paint for obtaining a multicolored coating film containing a luminous agent exhibiting polychromaticity, in which a plurality of different colors are visually recognized depending on the viewing angle. Has been described.

Further, Japanese Patent Application No. 10-295980 discloses a dichroic coating composition containing a metal oxide-coated silica flake pigment. However, a violet hue is applied to a three-coat top coat. No method has been disclosed for efficiently expressing the characteristics of the titanium dioxide-coated silica flakes.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a mica pigment coated on a color base coating film having an L value of 20 to 60. It is an object of the present invention to provide a laminated pearl coating film excellent in transparency by suppressing the yellowish color of the containing coating film as viewed from the shade position by using a silica flake coated with titanium dioxide.

[0006]

According to the present invention, there is provided a step of forming a color base coating film on a substrate having an undercoat film and an intermediate coating film formed thereon; forming a mica base coating film on the color base coating film; Forming a clear coating film thereon without curing it; and curing the mica base coating film and the clear coating film by heating, wherein the color base coating film is formed. The mica-based paint forming the mica-based coating film has a titanium dioxide-coated silica flake with a pigment concentration (PWC) of 1 to 1
An object of the present invention is to provide a method for forming a laminated pearl coating film, characterized in that it is contained in a range of 0%, whereby the above object is achieved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Color Base Coating In the method of forming a mica coating of the present invention, a color base coating is used to form a color base coating.
The color base paint contains a coloring pigment, a film-forming resin, a curing agent, and the like.

Examples of the color pigment contained in the color base paint include various organic and inorganic color pigments and extender pigments. Examples of color pigments include organic azo lake pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, dioxazine pigments, quinacridone pigments, and isoindolinones. Pigments, metal complex pigments, inorganic graphite, yellow iron oxide, red iron oxide, carbon black, titanium dioxide, etc.
Calcium carbonate, barium sulfate, clay, talc and the like are used. In addition, a color base coating film having a desired hue can be formed by using one or a combination of two or more of the above color pigments.

However, the lightness of the color base coating film used in the method for forming a laminated pearl coating film of the present invention is 20 to 40 in L value.
If it exceeds the upper limit, it will be too white and the base concealing property will be reduced, and if it is below the lower limit, it will be too black. Preferably it is 30-50.

Further, as the color pigments to be contained in the color base paint, Shanin blue pigments, Shanin green pigments, perylene pigments, quinacridone pigments, dioxane pigments, inorganic pigments blue, green and yellow, iron oxide red It is preferable to use a pigment iron oxide yellow pigment or the like mainly in combination, and the content of the pigment in the color base paint is 0.01 to 5.0%.
By setting to WC), a color base coating film having good hiding properties can be obtained. If it is below the lower limit, the undercoat concealing property is reduced, and if it is above the upper limit, the appearance is reduced. Preferably 0.1
~ 3.0%. The pigment concentration refers to the weight concentration (%) of the pigment contained in the coating composition.

The above-mentioned film-forming resin and curing agent include, for example, 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. These preferred solid contents in the paint are 30 to 70% by weight at the time of production and 10 to 5% at the time of application.
The range is 0% by weight. The dry film thickness of the coating film formed by coating is preferably 10 to 30 μm.

Further, a viscosity control agent can be added to the color base paint in order to ensure the workability of the coating. As the viscosity control agent, those which generally exhibit thixotropic properties can be used, for example, swelling dispersions of fatty acid amides, amide-based fatty acids, polyamide-based ones such as long-chain polyaminoamide phosphates, and colloidal swelling dispersions of polyethylene oxide Body, such as polyethylene-based, organic acid smectite clay, organic bentonite-based, such as montmorillonite, inorganic pigments such as aluminum silicate and barium sulfate, flat pigments that exhibit viscosity depending on the shape of the pigment, crosslinked or non-crosslinked Resin particles and the like can be mentioned as viscosity control agents.

Further, the color base paint may contain other additives, if desired. Such additives include, for example, surface conditioners such as silicones and organic polymers, UV absorbers, hindered amines, hindered phenols, and the like. These amounts are within the range known to those skilled in the art.

The total amount of the pigment contained in the color base paint is 3 to 70% as a pigment concentration (PWC), preferably 4 to 65%, more preferably 5 to 60%.
%. If it exceeds the upper limit, the appearance of the coating film will be reduced.

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.

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.

Mica Base Coating In the method for forming a metallic coating of the present invention, a mica base coating is used for forming a mica base coating. The mica-based paint contains titanium dioxide-coated silica flakes, a film-forming resin, a curing agent, and if necessary, a mica pigment.

The above-mentioned titanium dioxide-coated silica flake pigment is obtained by coating silica flake pigment with titanium dioxide. This coating layer is coated with metal oxides such as titanium dioxide and their hydrates, thereby having a pearl-like, metal-like and iridescent effect, and the thickness of the coating layer gives a violet color feeling Things. This silica flake pigment coated with titanium dioxide has an average particle size (D ₅₀ ) of about 3 to ₅₀ μm.
m, preferably about 5 to 45 μm, and a thickness of about 0.1 to
Those having a thickness of 2 μm are preferred.

The above mica-based paint contains a titanium dioxide-coated silica flake pigment. The content of the titanium dioxide coated silica flake pigment is determined by the pigment concentration (PW
C) The range is 1 to 10%. When the ratio exceeds the upper limit, the appearance of the coating film decreases, and when the ratio is lower than the lower limit, the saturation does not improve. Preferably, it is 1% to 7.0%.

Specific examples of the titanium dioxide-coated silica flake pigment include “Silica flake E” manufactured by Merck Japan.
M-325514 "and the like.

The mica pigments used as required are those usually used in metallic 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, a scale-like shape is preferable, and the average particle size (D ₅₀ ) is 2 to ₅₀ μm.
m and a thickness of 0.1 to 3 μm are suitable.

The above interference mica pigment, colored mica pigment and
And white mica pigment, Ti
O_Two, SnO_Two, ZrO_Two, Fe_TwoO_Three, ZnO_Two, Cr
_TwoO_Three, V _TwoO_FiveAnd metal oxides such as their hydrates
The coated mica pigment, pearl foil, metal-like and
In addition to having an iridescent effect, the metal oxide species and its coating
The thickness of the ring layer provides the color sensation played. this
TiO inside_Two, Fe_TwoO_ThreeUniformly coated with metal oxides such as
These 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, alumina flake having the interference light can be used.

When the above mica pigment is used, the mixing ratio between the silica flake pigment and the mica pigment is preferably in the range of 9/1 to 5/5, and when the mixing ratio of the mica pigment exceeds the upper limit, the silica flake pigment is used. The effect of using is reduced. More preferably, it is 8/1 to 6/5. Specifically, since the hue of the silica flake pigment is a violet color, it is preferable to use a mica pigment having a similar color or at least an adjacent color. For example, “Exterior Marine Highlight Violet” having a violet interference color manufactured by Engelhard Co., Ltd., or “Iriodin Ultra 7215W2” having a red interference color manufactured by Merck Japan Co., Ltd. or “Iriodin having a blue interference color” Ultra
7225W2 ". By using these, excellent effects can be obtained.

The film-forming resin contained in the mica base paint is not particularly limited, and those mentioned in the description of the color base paint can be used.
When the mica-based paint is used as a water-based paint, US Pat.
A film-forming resin specifically described in JP-A No. 04 or the like can be used.

The above mica-based paint can contain a viscosity controlling agent in order to ensure the workability of the coating. Specifically, those described in the description of the color base coating film can be used.

The amount of the viscosity control agent to be added to the above mica-based paint 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 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 deteriorates, and
If the amount is less than the weight part, the effect of controlling the viscosity cannot be obtained, which may cause the layer to adapt or reverse.

The total solid content of the mica-based paint is 1
It is 0 to 60% by weight, preferably 15 to 55% by weight.

The form of the mica-based paint used in the present invention includes an organic solvent type and an aqueous type (water-soluble, water-dispersible,
Emulsion) or non-aqueous dispersion type, and if necessary, a curing catalyst, an ultraviolet absorber, an antioxidant, a surface preparation agent and the like can be used.

Clear Coating In the method for forming a laminated pearl coating of the present invention, a clear coating is used for forming the clear coating. The clear paint contains a film-forming resin, a curing agent, and the like. The film-forming resin is not particularly limited, and a film-forming resin such as an acrylic resin, a polyester resin, an epoxy resin, or a urethane resin can be used, and these are an amino resin and / or a block resin. Used in combination with a curing agent such as an isocyanate resin. From the viewpoints of transparency and acid etching resistance, a combination of an acrylic resin and / or a polyester resin and an amino resin, or an acrylic resin and / or a polyester resin having a carboxylic acid / epoxy curing system is exemplified.

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

The clear paint is applied in an uncured state after the mica base paint is applied, so that the paint film is formed by a so-called wet-on-wet method. It is preferable to contain the above-mentioned viscosity controlling agent in order to prevent the above. The content is
0.01 to 10 parts by weight, preferably 0.00 parts by weight, based on 100 parts by weight of the resin solid content of the top clear coating composition.
It is added in an amount of 2 to 8 parts by weight, more preferably 0.03 to 6 parts by weight. If the amount exceeds 10 parts by weight, the appearance deteriorates,
If the amount is less than 0.1 parts by weight, the effect of controlling the viscosity cannot be obtained, which may cause a problem 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 type and a powder type. A catalyst, a surface preparation agent and the like can be used.

Substrates The coating film forming method of the present invention can be applied to various substrates, for example, metals,
Glass, cloth, plastic, foam, etc., especially metal surface,
And can be advantageously used for castings, but is particularly preferably used for metal products that can be subjected to cationic electrodeposition coating.

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.

Undercoating The cationic coating and anion coating can be used as the electrodeposition paint which is applied on the chemical conversion-treated steel sheet and which forms the undercoating used in the metallic coating forming method of the present invention.
The cationic electrodeposition coating composition gives a laminated coating film having excellent corrosion protection.

Intermediate coating film In the method for forming a metallic coating film of the present invention, the intermediate coating film conceals underlying defects, ensures surface smoothness after overcoating (improves appearance), and provides physical properties of coating film (impact resistance). , Chipping resistance, etc.). To form the intermediate coating film, an intermediate coating material is used, and the intermediate coating material includes various organic and inorganic color pigments, extender pigments, a film-forming resin, a curing agent, and the like.

As the coloring pigment used in the intermediate coating, for example, those described in the above color base coating are used. Further, flat pigments such as aluminum powder and graphite powder may be added.

As a standard, a gray intermediate coating material 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.

The film-forming resin used in the intermediate coating composition is not particularly limited, and for example, those described in the above color base coating composition can be used. A combination of an alkyd resin and / or a polyester resin and an amino resin is preferred from the viewpoint of pigment dispersibility or workability.

After being applied onto the undercoated base material, it can be used in an uncured state. However, when the intermediate coating film is cured, the curing temperature is 100 to 180 ° C., preferably 1 to 180 ° C.
By setting the temperature to 20 to 160 ° C., a cured coating film having a high degree of crosslinking can be obtained. When the amount exceeds the upper limit, the coating film becomes hard and brittle, and when the amount is less than the lower limit, curing is not sufficient. The curing time varies depending on the curing temperature, but is suitably from 120 ° C to 160 ° C for 10 to 30 minutes.

The forming method Figure 1 of the laminated pearl paint film is a cross-sectional view showing an example of a laminated pearl paint film formed by the method of the present invention. On the base material 6, an undercoating film 5, an intermediate coating film 4, a color base coating film 3, a mica base coating film 2,
And a clear coating film 1 are formed.

When forming the laminated pearl coating film, first, an undercoating film 5 and an intermediate coating film 4 are formed on a substrate 6. The formation method may be any method known to those skilled in the art.

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

The thickness of the coating film at the time of coating with the color base coating material in the present invention varies depending on the desired use, but in most cases, 10 to 30 μm is useful. When the limit is exceeded,
In some cases, the sharpness is deteriorated, and problems such as unevenness or flow during coating occur. If the lower limit is not reached, the base cannot be concealed and the film is cut.

The color base coating may or may not be cured. When the color base coating film is cured after coating, the curing temperature should be 100 to 180 ° C, preferably 12 to 180 ° C.
By setting the temperature to 0 to 160 ° C, a cured coating film having a high degree of crosslinking can be obtained. When the amount exceeds the upper limit, the coating film becomes hard and brittle, and when the amount is less than the lower limit, curing is not sufficient. The curing time varies depending on the curing temperature, but is suitably from 120 ° C to 160 ° C for 10 to 30 minutes.

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

The mica base paint used for forming the mica base coating film 2 is similar to the above color base paint.
It can be applied by a rotary atomizing electrostatic coating machine such as μμ bell, μ bell, etc., and the dry film thickness of the coating film is 10 to 30 μm.
Used in the m setting.

The clear coating film 1 applied after the formation of the mica base coating film 2 is formed in order to smooth and protect irregularities, flickers and the like caused by the brilliant pigment contained in the mica base coating film 2. You. 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 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. If the upper limit is exceeded, problems such as splashes or sagging may occur during coating. If the lower limit is not reached, irregularities on the base cannot be concealed.

Thereafter, the coating film thus laminated is cured. However, when the color base paint and the mica base paint are used as aqueous paints, in order to obtain a good finished paint film, the paint film is formed after each formation.
It is desirable to heat at 80 ° C. for 2 to 10 minutes.

After the application of the clear coating film, the coating film is cured. Curing temperature of 100-180 ° C, preferably 120
By setting the temperature to 160 ° C., a cured coating film having a high degree of crosslinking can be obtained. When the amount exceeds the upper limit, the coating film becomes hard and brittle, and when the amount is less than the lower limit, curing is not sufficient. The curing time varies depending on the curing temperature, but is suitably from 120 ° C to 160 ° C for 10 to 30 minutes.

The film thickness of the laminated coating film formed in the present invention is usually 30 to 300 μm, preferably 50 to 2 μm.
50 μm. If it exceeds the upper limit, the physical properties of the film such as a thermal cycle decrease, and if it falls below the lower limit, the strength of the film itself decreases.

[0054]

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 A color base paint was produced with the following composition (PWC = 17%). The L value of the coating film formed from this color base paint was 40 when measured with a Minolta CR-200 (a color difference meter manufactured by Minolta).

[0056]

[Table 1]

Production Example 2 Production of mica-based paint A mica-based paint was produced with the following composition (PWC = 6%).

[0058]

[Table 2]

Example 1 Formation of laminated pearl coating film 0.8 cm thick, 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.
Painted by "Auto REA" (Ransburg air electrostatic coating machine) on two stages at 2-minute intervals.
A color base coating was baked for 0 minutes. Next, the mica base paint of the above production example was similarly electrostatically coated so that the dry film thickness became 15 μm. Next, after setting for 7 minutes, the clear paint "Super Rack O-380 Clear" (Nippon Paint Co., Ltd., acid / epoxy curable acrylic resin paint) is further wet-on-wet.
Was subjected to a rotary atomization type electrostatic coating with a μμ bell so that the dry film thickness became 30 μm. It was baked at 140 ° C. for 20 minutes to form a coating film for evaluation.

The appearance of the obtained laminated pearl coating film was visually judged from the viewpoint of highlight and shade, from the viewpoint of transparency and hue, according to the following judgment rank.

Judgment criteria:

[Table 3]

Further, the reflection intensity (b
Value) with a gonio colorimeter “Gnome Spectrophotometer GSP-
Using "Type 1", the measurement was performed at every 10 degrees in the colorimetric range from -80 degrees to 80 degrees, and summarized in Table 4. Further, the obtained reflection intensity (b value) is plotted in FIG. 2 with the measurement angle as the horizontal axis.

Table 4 shows the above evaluation results.

COMPARATIVE EXAMPLE 1 Instead of the silica flake pigment used in Example 1, a mica-based paint prepared in advance using the same amount of Exterior Marine Highlight Violet (an interference mica pigment manufactured by Engelhard Co.) having the same hue was used. Coating and evaluation were performed in the same manner as in Example 1 except that a coating film was formed by using the same.

Table 4 shows the evaluation results.

[0067]

[Table 4]

The laminated pearl coating of the example according to the present invention
From the results of Table 4 and the graph of FIG.
At the position of the highlight of 0 degree, an unspecified value (blue tint) is shown, and the colorimetric angle is -80 to
At the position of the shade corresponding to 10 degrees, a positive value (yellow), which is a complementary color, was suppressed, and the hue of violet was able to be improved as a whole.

[0069]

According to the method of the present invention, at the highlight position, a pearly feeling like interference violet mica without unevenness is exhibited, and a complementary color (yellow tint) at the shade position of the conventional mica pigment-containing coating film is obtained. Sensation) and blurred feeling could be eliminated, and the faded image could be wiped out. As a result, a laminated coating film could be formed so as to maximize the characteristics of the pigment component.

[Brief description of the drawings]

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

FIG. 2 Reflection intensity (b value) of the laminated pearl coating film of the present invention
Is a graph in which the measurement angle is plotted on the horizontal axis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Clear coating film, 2 ... Mica base coating film, 3 ... Color base coating film, 4 ... Intermediate coating film, 5 ... Undercoat coating film, 6 ... Base material.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 7/12 C09D 7/12 201/00 201/00 F term (Reference) 4D075 AE03 AE06 CB15 EA02 EA43 EC04 EC54 4F100 AA20D AB03A AC05D AK25E AK36B AK41B AK53E AT00A BA05 BA07 BA10A BA10E CA13D CC00B CC00C CC00D CC00E CC03E EH662 EJ082 EJ422 EJ68A JN22 4J038 CD091 CG001 DD001 PC121 HA446 HA08 KA03 PC07

Claims (2)

[Claims] 1. A step of forming a color base coating film on a substrate on which an undercoat coating film and an intermediate coating film are formed; forming a mica base coating film on the color base coating film, and A method for forming a laminated pearl coating film, comprising: a step of forming a clear coating film; and a step of curing the mica-based coating film and the clear coating film by heating. 60,
Further, the mica-based coating material for forming the mica-based coating film has a titanium dioxide-coated silica flake having a pigment concentration (PW
C) A method for forming a laminated pearl coating film, which is contained in the range of 1 to 10%. 2. A laminated pearl coating film formed by the method according to claim 1.