JP2001170559A - Method for forming pearl coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pearl coating film giving pearl feeling, brilliance feeling and shining feeling when it is seen from any directions, by suppressing cloudiness feeling and decoloring occurring in a coating film containing an interference mica pigment when it is seen from a shade position. SOLUTION: In this forming method for the pearl coating film, the pearl coating film is formed by sequentially forming a color base coating film, a mica bade coating film, and a clear coating film by a wet-on-wet method on a base material, on which an undercoating film and an intermediate coating film have been formed. The mica base coating film contains 0.01-50% silica particles based on the pigment weight(PWC).

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 film for automobiles used for painting automobile bodies and the like, and a laminated coating film obtained by the method.

[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 Japanese Patent Application Laid-Open No. 8-164358, a white pearl-like or silver pearl-like base coat and a clear coat comprising a colored base coat and a scaly mica powder coated with titanium oxide are applied wet-on-wet. There has been proposed a method for forming a multilayer coating film, which comprises simultaneously crosslinking and curing the coating film.

Further, Japanese Patent Application Laid-Open No. 11-114489 proposes a method of sequentially forming a color base paint containing an organic amide, a base material containing a glitter material containing a glitter material, and a clear paint to form a laminated coating film. I have.

[0004] Examination of the coating films obtained from these points in terms of design shows that, when viewed from the highlight position, the interference mica pigment is prepared so as to exhibit pearl-like luster to externally incident light. However, when viewed from the shade position, there is a problem that, due to the orientation of the interference mica pigment, a feeling of white cloudiness becomes strong and the color becomes so-called colorless.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to suppress the occurrence of cloudiness and colorlessness when viewed from the shade position, which occurs in a coating film containing interference mica pigment, and to provide a pearly feeling in any direction.
An object of the present invention is to provide a pearl coating film having a glittering feeling and a glittering feeling.

[0006]

According to the present invention, there is provided a color base coating film on a substrate on which an undercoat film and an intermediate coating film are formed.
In a method for forming a pearl coating film, in which a mica base coating film and a clear coating film are sequentially formed on a wet-on-wet basis,
The mica-based coating film contains 0.01 to 5% of silica particles.
The present invention provides a method for forming a pearl coating film, characterized by containing at a pigment concentration (PWC).

[0007] The present invention further provides the above color base coating film,
A white pigment is used as a color pigment at a pigment concentration of 30 to 75% (P
WC), and a method for forming a pearl coating film.

Another object of the present invention is to provide a laminated coating film formed by the above method. Hereinafter, the present invention will be described in more detail.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Color Base Coating In the method of forming a pearl 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, an organic amide, crosslinked resin particles, 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.

A white pigment, for example, titanium dioxide or the like is mainly used as a coloring pigment of the color base paint used in the method of forming a coating film of the present invention, and its content is 30%.
It is preferably contained at a pigment concentration (PWC) of ~ 75%, more preferably 45-65%. 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. By containing the white pigment in the above range, a so-called white color base coating film having a Munsell value of N7 to N9.5 can be formed.

The film-forming resin and curing agent of the color base paint used in the method of forming a coating film of the present invention include, for example, a film-forming resin such as an acrylic resin, a polyester resin, an alkyd resin, a fluorine-based resin, and the like. A curing agent such as a resin and / or a blocked polyisocyanate compound is used. These preferred solid contents in the paint are 30 to 70% by weight at the time of production and 10% at the time of application.
５０50% by weight. The dry film thickness of the coating film formed by coating is preferably 10 to 30 μm.

As the organic amide contained in the color base paint, those generally known as viscosity control agents for imparting thixotropy can be mentioned. Specifically, fatty acid amides are mentioned, and those available as commercial products are known in the form of powder or paste. This paste is generally diluted with a solvent such as xylene or alcohol.

Examples of the above fatty acid amide include diamide and polyamide. Diamide is a compound obtained by reacting a diamine with a hydroxyl group-containing fatty acid. Polyamide is a compound obtained by reacting a polybasic carboxylic acid, a diamine and a hydroxyl group-containing fatty acid. Number average molecular weight (Mn) is 1000 to 20
Generally, about 00 is used.

The content of the organic amide in the color base paint is based on 100 parts by weight of the resin solid content in the paint.
It is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 5 parts by weight, still more preferably 0.5 to 5 parts by weight.
３3 parts by weight. If the content of the organic amide is too small, the effects of the present invention cannot be sufficiently obtained, and the appearance of the coating film such as glossiness and color may be reduced. On the other hand, if the content of the organic amide is too large, the surface of the coating film may be roughened and the performance of the coating film may be reduced.

On the other hand, as the crosslinked resin particles used in the color base paint in the present invention, those generally known as a viscosity controlling agent can be used.
Resin particles referred to as “onAqueous Dispersion” can be used. As an example of this, there can be mentioned resin particles used in NAD paints described in Coloring Materials, Vol. 48 (1975), pp. 28-34. Further, polymerizable resin particles disclosed in JP-A-53-133236 can be used as the crosslinked resin particles in the present invention.

Of these, those which do not affect the gloss and color development when formed into a coating film are preferred, and non-crosslinked or crosslinked resins or particles utilizing the interaction of polar groups are more preferred. Most preferred are those obtained by polymerizing a monomer in the presence of a polyester resin having an amphoteric ionic group.

Examples of such crosslinked resin particles include those which are insoluble in organic solvents and have an average particle size of 0.02 to 0.5 μm. If the average particle size exceeds the upper limit, the stability will decrease. Further, the crosslinked resin particles, a resin having an emulsifying ability such as an alkyd resin or a polyester resin synthesized as a polyhydric alcohol component having a monomer having a zwitterionic group in the molecule, and a polymerization initiator Those obtained by emulsion polymerization of an ethylenically unsaturated monomer in an aqueous medium in the presence are preferred.

The crosslinked resin particles obtained by this method are:
In general, a monomer which is contained in an emulsion resin, does not contain a low-molecular emulsifier or a protective colloid which lowers the performance when formed into a coating film, and has two or more radically polymerizable ethylenically unsaturated groups in the molecule. Since it is crosslinked by copolymerization, the coating film is excellent in water resistance, solvent resistance, gloss and the like.

The content of the crosslinked resin particles in the color base paint is 2 to 20 parts by weight based on 100 parts by weight of the resin solids.
Parts by weight, more preferably 4 to 17 parts by weight.
Parts by weight, and more preferably 6 to 15 parts by weight. If the content of the crosslinked resin particles is too small, the appearance of the coating film such as glossiness and color may deteriorate. On the other hand, if the content of the crosslinked resin particles is too large, the coating film may be rough and the coating film performance may be reduced.

In the present invention, when the color base paint contains crosslinked resin particles, the compounding ratio of the organic amide and the crosslinked resin particles is 1/50 to 1.5 as a ratio of the solid content of the organic amide / crosslinked resin particles. / 1, more preferably 1/20 to 1/1. If the amount of the organic amide in the compounding ratio is small, glossiness, color, and the like in the appearance of the coating film may be reduced. If the amount of the organic amide in the mixing ratio is too large, the coating film performance may be reduced.

The total content of the organic amide and the crosslinked resin particles is preferably 2 to 30 parts by weight, more preferably 4 to 20 parts by weight, based on 100 parts by weight of the resin solids in the color base paint. And more preferably 6 to 16 parts by weight. If the total content of these components is too small, the gloss and color appearance of the coating film appearance may decrease.On the other hand, if the total content is too large, the coating film becomes rough and the coating film performance deteriorates. May be.

Further, in the present invention, the color base paint may contain other additives, if desired. Such additives include, for example, surface conditioners such as silicone and organic polymers, ultraviolet absorbers,
There are hindered amines, hindered phenols and the like.

The total pigment concentration (PWC) in the paint including all the pigments is 3 to 70%, preferably 4 to 65%, and 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-based coating film In the method for forming a metallic coating film of the present invention, a mica-based coating material is used for forming a mica-based coating film. This mica-based paint contains mica pigment, film-forming resin,
It contains a curing agent and crosslinked resin particles.

The above mica pigments 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, scaly ones are preferable, and those having an average particle diameter (D ₅₀ ) of 2 to ₅₀ μm 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
Cover metal oxides such as titanium dioxide and iron oxide uniformly
What was done is used suitably.

For example, as an interference mica pigment having a white interference color, "Silalic T" manufactured by Merck Japan Ltd. is used.
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 a white color base coating film having the above-mentioned Munsell value of N7 to N9.5 is used as the color base coating film, "Silalic T60-10 W3" manufactured by Merck Japan Ltd. is used as a glitter material of the mica base coating material.
(Trade name), "Pearl Grace SME 9" manufactured by Nippon Koken
An interference mica pigment such as "0-9" (trade name) is used.
It is suitable for producing a white pearly feeling.

The concentration of the above mica pigment in the paint (PW
C) is generally at most 18.0%. Exceeding the upper limit lowers the appearance of the coating. Preferably, 0.01% to 1%
7.0%, and more preferably 0.01% to 16%.
0%.

In the method for forming a coating film of the present invention, hydrophilic silica particles are preferred as the silica particles contained in the mica-based coating. Here, “hydrophilic” means that the surface is the surface of the silica particles themselves or the surface of other inorganic substances, and is made lipophilic by a treating agent such as a silane coupling agent or an organic titanate. Has not been processed.

The silica particles may be granular particles containing SiO ₂ as a main component. For example, silica particles produced by a spray-drying method or a method such as pulverization and classification can be used.

The particle diameter of the silica particles is generally preferably about 2 to 100 μm, more preferably 3 to 100 μm.
It is 50 μm, more preferably 4 to 15 μm. For example, the colloidal silica “SIPENART” manufactured by Degussa, Inc.
22LS "and the like.

The preferable content of the silica particles is generally selected within the range of 0.5 to 7.0% by weight based on 100 parts by weight of the resin solid content of the mica-based coating. More preferably, it is 0.75 to 5.0% by weight. Below the lower limit, there is no effect, and above the upper limit, the appearance from the shade becomes too white and the appearance from the highlight becomes black.

When the silica particles are contained in the mica-based coating within the above range, the silica particles are substantially uniformly dispersed on the surface of the mica pigment, and irregular reflection of light by the silica particles occurs on the surface of the mica pigment, and It is thought that the light reflection angle or light reflection intensity when viewed as a coating film is irregularly reflected and changed.

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.

Further, the mica-based paint contains crosslinked resin particles in order to ensure the workability of coating.
As the crosslinked resin particles, those described in the description of the color base coating film described above can be used.

The amount of the crosslinked resin particles to be added to the above mica base paint is 0.01 to 10 parts by weight, preferably 0.02 to 10 parts by weight, based on 100 parts by weight of the resin solid content of the coating composition.
It is added in an amount of 8 parts by weight, more preferably 0.03 to 6 parts by weight. When the amount of the crosslinked resin particles exceeds 10 parts by weight, the appearance is deteriorated. When the amount is less than 0.1 part by weight, the effect of controlling the viscosity cannot be obtained, which causes a break-in or inversion between layers.

The total solid content of the above mica base 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 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, acrylic resin, polyester resin, epoxy resin,
A film-forming resin such as a urethane resin can be used, and these are used in combination with a curing agent such as an amino resin and / or a blocked 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 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-based paint is applied, so that the paint film is formed by a so-called wet-on-wet method. It is preferred to contain the above-mentioned crosslinked resin particles in order to prevent the above. The content of the crosslinked resin particles is 0.01 to 10 parts by weight based on 100 parts by weight of the resin solid content of the top clear coating composition,
Preferably 0.02 to 8 parts by weight, more preferably 0.02 parts by weight
It is added in an amount of 3 to 6 parts by weight. When the amount of the crosslinked resin particles is
If the amount is more than 10 parts by weight, the external appearance is deteriorated. If the amount is less than 0.1 part by weight, the effect of controlling the viscosity cannot be obtained, which causes 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 advantageously used for various substrates, for example, wood, metal, glass, cloth, plastic, foam, etc., particularly metal surfaces and castings. It can be used particularly preferably for metal products that can be coated.

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.

Undercoat Films As the electrodeposition paint which is applied on the chemical conversion-treated steel sheet and which forms the undercoat film used in the method for forming a metallic coating film of the present invention, cationic and anionic types can be used.
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 top coating (improves appearance), and provides physical properties of the 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 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.

The film-forming resin used in the intermediate coating is not particularly limited, and for example, those described in the above color base coating are 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 may 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.

Method for Forming Pearl Coating Film The method for forming a pearl coating film of the present invention is, as shown in FIG.
On the base material 6 on which the undercoat film 5 and the intermediate coat film 4 are formed,
This is a three-coat, one-baked lamination coating forming method in which a color base coating film 3, a mica base coating film 2, and a clear coating film 1 are sequentially formed by wet-on-wet, and then each coating film is simultaneously cured.

That is, in the method of the present invention, first, a color base paint is applied on the base material 6 on which the undercoat film 5 and the intermediate coat film 4 are formed to form the color base paint 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, Known as “μμ (micro micro) bell”, “μ (micro)
The coating film can be formed by a coating method in combination with a rotary atomization type electrostatic coating machine called "bell" or "metabell".

The thickness of the coating film when coated with the color base coating in the present invention varies depending on the desired application, 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.

In the pearl coating film forming method of the present invention, a mica base coating material and a clear coating material are further applied on the uncured color base coating film 3 by wet-on-wet coating as shown in FIG. A base coating film 2 and a clear coating film 1 are formed.

The mica base paint used to form the mica base coating film 2 in the present invention can be applied by a rotary atomizing type electrostatic coating machine such as μμ bell, μ bell, etc., similarly to the above color base paint. The dried film thickness of the coating film is set at 10 to 30 μm.

In the method for forming a coating film of the present invention, the clear coating film 1 applied after the formation of the mica base coating film 2 has irregularities, flickers and the like caused by the brilliant pigment contained in the mica base coating film 2. Formed to smooth and protect Specifically, as the coating method, μ
It is preferable to form a coating film by using a rotary atomizing type electrostatic coating machine such as a μ bell and a μ bell.

The dry film thickness of the clear coating film formed by the above clear paint 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, a three-coat, one-bake coating film is formed to cure the coating film thus laminated. However,
When using the above color base paint, mica base paint as an aqueous paint, in order to obtain a good finished coating film,
After each formation, the coating is applied at 60-100 ° C for 2-10
It is desirable to heat for minutes.

After the application of the clear coating film, the curing temperature for curing the coating film is 100 to 180 ° C., preferably 120 to 180 ° C.
By setting the temperature at 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.

[0065]

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 Production of color base paint A white color base paint was produced with the following composition (PWC = 60%, containing 1.4 parts of organic amide and 15 parts of crosslinked resin particles with respect to 100 resin solids). did. 33.00 parts of Typek CR-97 (titanium dioxide pigment manufactured by Ishihara Sangyo) 30.30 parts of thermosetting acrylic resin (manufactured by Nippon Paint Co., Ltd., hydroxyl value 45, acid value 15, number average molecular weight 21,000, solid content 50%) Uban 20N60 10.80 parts (Butylated melamine resin, Mitsui Toatsu Co., solid content 60%) FLOWON HR-2 3.00 parts (Kyoeisha Chemical Co., Ltd., organic amide, solid content 10%) Acrylic surface conditioner 0. 20 parts Crosslinked resin particles 16.00 parts (Nippon Paint Co., Ltd. structural viscosity imparting agent, solid content 20%) n-butanol 2.70 parts Xylol 4.00 parts Total 100.00 parts

Preparation of Mica Base Paint A mica base 1 paint was prepared with the following composition (PWC = 8%, containing 1 part of silica particles with respect to resin solid content of 100). Silaric T60-10 W3 2.70 parts (Merck Japan Co., Ltd. white interference mica pigment, average particle size 19 μm) Thermosetting acrylic resin 43.00 parts (Nippon Paint Co., Ltd., hydroxyl value 45, acid value 15, number average molecular weight) 21,000, solid content 50%) Uban 20N60 15.40 parts (Mitsui Toatsu Co., Butylated melamine resin, solid content 60%) SIPERNAT 22LS 1.54 parts (Degussa Co., Ltd., colloidal silica, solid content 20%) Acrylic Surface control agent 0.20 parts Crosslinked resin particles 16.00 parts (Nippon Paint Co., Ltd. structural viscosity imparting agent, solid content 20%) n-butanol 4.20 parts Xylol 4.13 parts Toluene 12.83 parts Total 100.00 Department

Example 1 Formation of pearl 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 15 μm.
The coating was performed by “Auto REA” (air electrostatic coating machine manufactured by Ransburg) on two stages at intervals of 2 minutes. After an interval of 4 minutes, the mica base 1 paint of the above production example was electrostatically coated in a wet-on-wet manner 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) was further wet-on-wet.
Rotary atomization type electrostatic coating was performed 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 metallic coating film was visually judged from the viewpoint of highlight and shade from the viewpoints of transparency and brilliancy according to the following criteria. <Judgment criteria>5; fairly good 4; fairly good 3; excellent 2; fairly poor 1; fairly poor

Further, the reflection intensity (L ^*
Value intensity) by using a gonio colorimeter “gono spectrophotometer GS” manufactured by Murakami Company.
Using the "P-1 type", measurement was performed at each measurement angle from -20 degrees to 70 degrees, and the results are summarized in Table 1. Further, the obtained reflection intensity (L ^* value intensity) is plotted in FIG. 2 with the measurement angle as the horizontal axis. Table 1 shows the evaluation results.

Example 2 SIP contained in the mica base 1 paint used in Example 1
A mica base 2 paint containing 4.62 parts of ERANT 22LS (colloidal silica manufactured by Degussa, solid content: 20%) was prepared in advance, and this paint was used to prepare Example 1.
A laminated coating film was prepared in the same manner as described above and evaluated.

Comparative Example 1 Evaluation was made in the same manner as in Example 1 except that a coating film was formed using a mica base 3 paint prepared in advance, except for the silica particles used in Example 1. Table 1 shows the evaluation results.

[0074]

[Table 1]

The laminated coating films of Examples 1 and 2 according to the present invention have a colorimetric angle of 30 from the results of Table 1 and the graph of FIG.
In the highlight position corresponding to ６０60 degrees, the pearly sensation of the interference mica pigment is shown with a high reflection intensity, and in the shade position where the colorimetric angle is −20 to 10 degrees, the reflection intensity is reduced and the color is colorless. , As shown in the graph, the reflection angle changes.
That is, the reflection intensity could be improved.

[0076]

According to the method of the present invention, the light reflection angle or the light reflection intensity of the conventional mica pigment-containing coating film can be changed, and in practice, there is no uneven mica at the highlight position. And the opacity at the shade position is eliminated, and the glitter and the original hue can be developed. As a result, a laminated coating film could be formed so as to maximize the characteristics of the individual pigment components. Therefore, by using the method of the present invention for an automobile or the like having a curved surface, the appearance can be improved more than ever.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure of a laminated coating film of the present invention.

FIG. 2 is a graph showing a relationship between a measurement angle and a reflection intensity (L ^* value intensity) of a laminated coating film obtained by the method of the present invention.

[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 Z 201/00 201/00 F term (reference) 4D075 AE06 CA47 CB15 DA06 DB02 DC12 EA02 EA43 EC03 EC04 EC11 EC54 4J038 CD091 CG141 DA112 DD001 DD121 DG111 DG191 EA011 HA216 HA446 HA556 JB12 KA03 KA08 KA20 NA01

Claims (3)

[Claims] 1. A method for forming a pearl coating film in which a color base coating film, a mica base coating film and a clear coating film are sequentially formed on a substrate on which an undercoat coating film and an intermediate coating film are formed by wet-on-wet. A method for forming a pearl coating film, wherein the mica-based coating film contains silica particles at a pigment concentration (PWC) of 0.01 to 5%. 2. The method for forming a pearl coating film according to claim 1, wherein the color base coating film contains a white pigment as a coloring pigment at a pigment concentration (PWC) of 30 to 75%. 3. A laminated coating film formed by the method according to claim 1.