JP3164194B2 - Method of forming a coating with design properties - Google Patents

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 coating film having a design property such as two-tone coating or stripe coating in which the surface of a workpiece such as an automobile body is painted in two colors.

[0002]

2. Description of the Related Art Conventionally, the following method has been practiced as a two-ton coating method. First, a steel sheet for a car that has been subjected to a chemical conversion treatment is subjected to electrodeposition coating, baked, and further subjected to intermediate coating and baked. Then, the first coating film is applied to the portion to be the first color coating film of the two-tone coating and baked. Alternatively, after the top coat base coat of the first coating film is applied, a top coat clear is applied by wet-on-wet and baked. Subsequently, the boundary portion of the two-tone coating is masked, and in some cases, the portion to be the coating film of the second color of the two-ton coating is sanded, and the second coating film is applied and baked. Or after applying the top coat base coat of the second coating film, wet
Paint and bake the topcoat clear on wet.
Finally, the masking tape is removed to complete the two-tone coating.

[0003]

However, such a conventional two-tone coating method requires a lot of man-hours, and the appearance of the parting line between the first coating film and the second coating film of the two-ton coating becomes poor. Also, there is a problem that chipping resistance and peeling resistance due to stepping stones and the like are deteriorated.

An object of the present invention is to provide a two-tone coating method which solves the above-mentioned problems, that is, a coating film having a design property such as two-tone coating or stripe coating can be formed with a smaller number of baking steps than before. It is an object of the present invention to provide a method capable of forming a coating film having superior chipping resistance and peeping resistance due to a stepping stone or the like as compared with a coating film obtained by a conventional coating process.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by performing a coating process in a specific order and using a specific resin mixture as a binder. Finding that the above issues can be solved,
The present invention has been completed.

That is, the method of forming a coating having a design according to the present invention comprises the following steps: (1) a step of applying an undercoat to a metal plate to form an undercoat; and (2) a step of baking and curing the undercoat. (3) A mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin as a binder on the cured undercoat film. A step of applying an intermediate coating containing a coloring pigment to form an intermediate coating, (4) a mixed resin comprising a polyester resin and a melamine resin, at a required position on the intermediate coating without curing the intermediate coating; A mixed resin composed of acrylic resin and melamine resin, or a mixed resin composed of polyester resin, acrylic resin and melamine resin as a binder, Forming a first base top coating film by applying a first base top coating material containing a pigment, (5)
Without curing the intermediate coat and the first top coat base coat, on the first top coat base coat, a mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a polyester resin,
A step of applying a first clear top coat made of a mixed resin comprising an acrylic resin and a melamine resin to form a first clear top coat, (6) the intermediate coat, the first top coat base coat and the first top clear coat (7) a step of masking required portions on the cured first clear top coat with a masking material, (8)
On the surface to be coated other than the masked portion, a mixed resin of a polyester resin and a melamine resin, a mixed resin of an acrylic resin and a melamine resin, or a mixed resin of a polyester resin, an acrylic resin and a melamine resin as a binder. , Containing a color pigment,
Forming a second top coat by applying a second top coat of a color different from the top coat base paint, (9) baking and curing the entire coated surface, and (10) removing the masking material. It is characterized by the following.

[0007] Further, the method of forming a decorative film according to the present invention comprises: (1) a step of applying an undercoat paint on a metal plate to form an undercoat film; (2) a step of baking and curing the undercoat film. (3) On the cured undercoat, a mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin as a binder, A step of applying an intermediate coating containing a color pigment to form an intermediate coating, (4) a mixed resin comprising a polyester resin and a melamine resin, and an acrylic resin at a required position on the intermediate coating without curing the intermediate coating; Resin and melamine resin or polyester resin, acrylic resin and melamine resin mixed resin as binder, light A step of applying a first topcoat base paint containing a pigment and a color pigment to form a first topcoat basecoat; (5) the first topcoat base without curing the intermediate coat and the first topcoat basecoat; A first overcoating clear paint composed of a mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin, is applied to the first coating. Forming a clear top coat, (6) baking and curing the intermediate coat, the first top coat base coat, and the first clear top coat, and (7) a requirement on the cured first clear top coat. (8) a step of masking a portion with a masking material, and (8) a polyester resin and a melamine resin on the surface to be coated other than the masked portion. A mixed resin composed of a resin, a mixed resin composed of an acrylic resin and a melamine resin, or a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin is used as a binder, and contains a bright pigment and a colored pigment. Forming a second topcoat base film by applying a second topcoat base paint having a different color from the above, (9) a polyester resin and a polyester resin on the second topcoat base film without curing the second topcoat base film. Forming a second top clear coating by applying a second top clear coating made of a mixed resin composed of a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin; (10) a step of baking and curing the entire painted surface, and (11) a step of removing the masking material. It is characterized by comprising.

Hereinafter, the present invention will be described in detail. Polyester resin used as a binder component of the paint in the present invention is a known component in combination with a polyol component and a polybasic acid or an acid anhydride thereof, which are ordinary raw materials constituting the same, and a fatty acid used as necessary. It can be produced by an esterification reaction. The method for producing the polyester resin is not particularly limited, and a known method such as a melt condensation method, an azeotropic condensation method, or a combination thereof can be used.

As the above polyol component, for example,
Ethylene glycol, diethylene glycol, neopentyl glycol, butylene glycol, hexanediol, 2,2-dimethylpentanediol-1,3, hydrogenated bisphenol A, trimethylolpropane, 1,6-hexanediol, trimethylolcyclohexane, pentaerythritol, Glycerin, tricyclodecane dimethanol and the like can be mentioned. Other than these, 2,2-dimethyl-3-hydroxypropanol, 2,2-dimethyl-3-hydroxypropionate, tris (2-hydroxyethyl) isocyanurate and the like can also be used. These polyol components may be used alone or in combination of two or more.

Further, polybasic acids and acid anhydrides thereof include:
For example, phthalic anhydride, terephthalic acid, isophthalic acid,
Tetrahydrophthalic anhydride, maleic anhydride, succinic acid, fumaric acid, glutaric acid, adipic acid, sebacic acid,
Trimellitic anhydride, dimethylolpropionic acid and the like can be mentioned. These polybasic acids and their acid anhydrides may be used alone or in combination of two or more.

Further, the fatty acids include, for example, fatty acids obtained from octylic acid, nonanoic acid, lauric acid, stearic acid and soybean oil, coconut oil, safflower oil, cottonseed oil, dehydrated castor oil, tall oil and the like. it can. These fatty acids may be used alone or in combination of two or more.

The melamine resin used as a binder component of the coating material in the present invention includes a methylolated amino compound obtained by reacting an aldehyde with an amino component such as melamine, benzoguanamine, urea, and acetoguanamine. Examples of the aldehyde include acetaldehyde, formaldehyde, paraformaldehyde and the like. Further, those obtained by etherifying the methylolated amino compound with an appropriate alcohol can also be used. Examples of the alcohol used for the etherification include methyl alcohol, ethyl alcohol, and the like.
n-propyl alcohol, n-butyl alcohol, i-
Examples thereof include propyl alcohol and i-butyl alcohol.

In the present invention, it is used as a binder component of a paint.
Examples of the acrylic resin used include, for example, a hydroxyl group-containing resin.
Copolymers of vinyl monomers and other vinyl monomers
Can be mentioned. As a hydroxyl-containing vinyl monomer
Is, for example, hydroxypropyl (meth) acrylate
G, 2-hydroxyethyl (meth) acrylate, etc.
C of (meth) acrylic acid_Two~ C_{twenty four}Hydroxyalkyl
Ester; N-methylol (meth) acrylamide, N
-Hydroxyethyl (meth) acrylamide, N, N-
Such as dihydroxyethyl (meth) acrylamide
Mono- or di-C of (meth) acrylic acid₁~ C₁₈Hydro
Xylalkylamides. Other vinyl mono
For example, methyl acrylate, ethyl alcohol
Acrylate, propyl acrylate, n-butyl acrylate
Rate, i-butyl acrylate, hexyl acrylate
G, 2-butyl acrylate, octyl acrylate,
2-ethylhexyl acrylate, 2-ethylbutyl acrylate
C of acrylic acid such as acrylate ₁~ C_{twenty four}Alkyl esthetic
And methyl methacrylate, ethyl methacrylate
G, propyl methacrylate, n-butyl methacrylate
G, i-butyl methacrylate, pentyl methacrylate
G, hexyl methacrylate, 2-ethylhexyl meth
Acrylate, lauryl methacrylate, stearyl meth
C of methacrylic acid such as acrylate₁~ C_{twenty four}Alkyl S
Carboxyl groups such as ter and acrylic acid and methacrylic acid
Vinyl monomer, styrene, vinyl toluene
And glycidyl methacrylate.

The method of copolymerizing these monomers is not particularly limited, and a known method may be used. The method may be an organic solvent solution type or a non-aqueous dispersion type by a polymerization method. be able to. The undercoat paint used in the present invention refers to a paint that is first coated on a metal plate to form a coating film, and is intended for strong coating between a metal plate and a coating film to be subsequently applied, Electrodeposition (ED) paints and the like are preferably used.

In the present invention, the mixed resin composed of the polyester resin and the melamine resin used as a binder for the intermediate coating composition is preferably 20 to 95% by weight, more preferably 30 to 90% by weight of the above polyester resin on a solid basis. Containing the above melamine resin preferably in the range of 5 to 80.
%, More preferably 10 to 70% by weight. When the blending amount of the polyester resin is less than 20% by weight, the dispersibility tends to decrease, and the gloss tends to decrease. The film tends to be soft. When the amount of the melamine resin is less than 5% by weight, the curing performance tends to be insufficient. On the other hand, when the amount is more than 80% by weight, the formed coating film is hard and brittle. Tend.

In the present invention, the mixed resin composed of an acrylic resin and a melamine resin used as a binder for the intermediate coating composition is preferably the above-mentioned acrylic resin on a solids basis,
0 to 95% by weight, more preferably 30 to 90% by weight, preferably 5 to 80% by weight of the above melamine resin,
More preferably, the content is 10 to 70% by weight.
When the amount of the acrylic resin is less than 20%, the dispersibility tends to decrease and the strength of the coating film tends to decrease, while when it exceeds 95% by weight, the curing performance is insufficient. And the coating film tends to be soft or the appearance of the coating film applied by wet-on-wet tends to be deteriorated. If the amount of the melamine resin is less than 5% by weight, the curing performance becomes insufficient,
There is a tendency that the appearance of a coating film coated by on-wet is reduced, while if it exceeds 40% by weight, the formed coating film tends to be hard and brittle.

In the present invention, the mixed resin comprising a polyester resin, an acrylic resin and a melamine resin used as a binder for the intermediate coating composition is preferably 20 to 80% by weight, more preferably 30 to 80% by weight of the above polyester resin on a solid content basis. 70% by weight, preferably not more than 70% by weight of the above acrylic resin, more preferably 5 to 40% by weight
And preferably contains 5 to 70% by weight, more preferably 10 to 50% by weight of the above melamine resin. If the blending amount of the polyester resin is less than 20% by weight, the dispersibility tends to decrease and the gloss tends to decrease. The film tends to be soft. If the blending amount of the acrylic resin exceeds 70 wt.
The appearance of the coating film by on-wet coating tends to deteriorate. On the other hand, when the amount of the melamine resin is less than 5% by weight, the curing performance becomes insufficient.
When it exceeds, the formed coating film tends to be hard and brittle.

The intermediate coating used in the present invention is a mixed resin comprising the above polyester resin and the above melamine resin, a mixed resin comprising the above acrylic resin and the above melamine resin, or a mixture of the above polyester resin, the above acrylic resin and the above melamine resin. In addition to having a mixed resin, particularly a mixed resin having a molecular weight and a composition particularly suitable for use in an intermediate coating composition, and a coloring pigment as essential components, an organic solvent, a coating surface adjusting agent, a curing catalyst, and the like as required. And additives such as a pigment and a pigment dispersant.

Examples of the above color pigments include inorganic pigments such as titanium dioxide, zinc white, lead white, carbon black, acetylene black and graphite. Examples of the organic solvent include, for example, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, alcohols, esters, ethers, ketones, and the like.Specifically, toluene, xylene, methyl Naphthalene, naphtha, mineral spirit, cyclohexane, methanol, ethanol,
Examples include isopropanol, n-butanol, ethyl acetate, butyl acetate, glycol monoethyl ether, glycol monobutyl ether, glycol monomethyl ether acetate, glycol monoethyl ether acetate, methyl ethyl ketone, methyl isobutyl ketone, and the like. Each of these solvents may be used alone.
A combination of more than one species may be used.

In the present invention, the mixed resin composed of the polyester resin and the melamine resin used as the binder of the first top coat base paint has been described as the mixed resin composed of the polyester resin and the melamine resin used as the binder of the intermediate paint. The same as the mixed resin,
The mixed resin composed of an acrylic resin and a melamine resin used as a binder of the topcoat base paint is the same as the mixed resin described as the mixed resin composed of the acrylic resin and the melamine resin used as the binder of the intermediate paint, Further, the mixed resin composed of a polyester resin, an acrylic resin and a melamine resin used as a binder of the first top coat base paint is also described as a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin used as a binder of the intermediate paint. It is the same as the mixed resin. However, when actually used, a mixed resin having a molecular weight, a composition, and the like particularly suitable for use in each of the intermediate coating and the first overcoat base coating is appropriately selected and used.

The first overcoat base paint used in the present invention is a mixed resin composed of the polyester resin and the melamine resin, a mixed resin composed of the acrylic resin and the melamine resin, or the acrylic resin, the polyester resin and the melamine resin. Mixed resin consisting of resin,
And the coloring pigment as an essential component, in the case of metallic coating, as the above-mentioned coloring pigment also having a brilliant pigment as an essential component,
For example, titanium dioxide, zinc white, lead white, carbon black, acetylene black, graphite, vermilion, cadmium red, antimony vermilion, red iron, blue blue, ultramarine, cobalt blue, chrome oxide green, guinea green, chrome green, zinc green, oxide Inorganic pigments such as iron, azo-based, phthalocyanine-based, quinacridone-based,
Organic pigments such as dioxazine type and isoindolinone type are exemplified.

Examples of the bright pigment include metal powder pigments such as aluminum powder, copper powder, bronze powder, mica powder coated with titanium dioxide, and mica-like iron oxide powder. In the present invention, the mixed resin composed of a polyester resin and a melamine resin used as a binder of the first top coat clear paint is the mixed resin described as the mixed resin composed of the polyester resin and the melamine resin used as a binder of the intermediate paint. Are the same.

In the present invention, the mixed resin comprising an acrylic resin and a melamine resin used as a binder of the first clear top coating composition is preferably 50 to 90% by weight, more preferably 60 to 90% by weight of the above acrylic resin on a solid basis. 8
0% by weight, and preferably contains 10% of the above melamine resin.
To 50% by weight, more preferably 20 to 40% by weight. When the blending amount of the acrylic resin is less than 50% by weight, the strength of the coating film tends to be weak or the chemical resistance tends to decrease. Tends to be insufficient. When the amount of the melamine resin is less than 10% by weight, the curing performance becomes insufficient or the wet-on
There is a tendency that the appearance of the coating film by wet coating tends to be deteriorated, while if it exceeds 50% by weight, the formed coating film tends to be hard and brittle.

In the present invention, the polyester resin, the acrylic resin and the melamine resin used as a binder for the first clear top coating composition are preferably mixed with the above polyester resin in an amount of 40 to 90% by weight on a solid basis.
More preferably, the content is 60 to 80% by weight, and the acrylic resin is preferably 40% by weight or less, more preferably 5 to 50% by weight.
30% by weight, preferably containing 10% of the above melamine resin.
To 50% by weight, more preferably 20 to 40% by weight. 40% by weight of polyester resin
If it is less than 90% by weight, the coating strength tends to be low. On the other hand, if it exceeds 90% by weight, the curing performance tends to be insufficient. If the amount of the acrylic resin exceeds 40% by weight, the appearance of the coating film by wet-on-wet coating tends to be deteriorated. When the amount of the melamine resin is less than 10% by weight, the curing performance becomes insufficient or the wet-on-
There is a tendency that the appearance of the coating film by wet coating tends to be deteriorated, while if it exceeds 50% by weight, the formed coating film tends to be hard and brittle.

In the present invention, the first top clear paint is
When a second topcoat or a second basecoat is applied thereon, a mixed resin based on polyester resin, acrylic resin and melamine resin in terms of adhesion (adhesion) with the second topcoat. Is preferred.

The second top coat used in the present invention contains the mixed resin and the color pigment described as the first top coat base paint, but has a different color from the first top coat base paint. . This difference in color may be due to the inclusion of a differently colored coloring pigment, and may be due to the first topcoat containing a bright pigment but the second topcoat not containing a bright pigment. . The second top coat used in the present invention is preferably one coat and excellent in durability, and among them, a mixed resin-based resin composed of a polyester resin and a melamine resin is suitably used.

The second topcoat base paint used in the present invention contains the mixed resin, bright pigment and color pigment described as the first topcoat base paint.
The first overcoat base paint is different from the first overcoat base paint in that it contains a different color pigment and / or a different kind of bright pigment, and among them, a mixed resin based paint composed of an acrylic resin and a melamine resin is preferably used.

The second top clear coating used in the present invention is a coating composed of the mixed resin described as the first top clear coating. In the present invention, both the first top clear coating and the second top clear coating are used. Is used, a masking operation is performed between the first clear top coating and the second clear clear coating, and the masking is provided on the first clear clear coating. In this case, the first clear clear coating and the first clear clear coating are used. The components and compositions are usually different from the second clear top coating.

In the method of forming a film according to the present invention, when the first overcoat base film and the second overcoat base film contain a bright pigment, the first overcoat clear paint and the second overcoat clear paint contain a bright pigment. As it protects the coating, the first top clear coating and the second top clear coating can be used as long as they have excellent durability and are transparent, and among them, a mixed resin composed of an acrylic resin and a melamine resin. The system type is preferably used.

[0030]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In Examples and Comparative Examples, “parts”, “%”, and “ratio” are based on weight. The coating materials used in the examples and comparative examples are as follows.

[Intermediate coating] Polyester resin "Beccolite M6012-60" (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) and melamine resin "Super Beckamine L-117"
-60 "(Dai Nippon Ink Chemical Industry Co., Ltd.) with a solid content ratio of 75/25: 35 parts, titanium oxide" R-36N "(Sakai Chemical Co., Ltd.) and carbon black" MA-100 "(trade name, manufactured by Mitsubishi Carbon Co.) at a ratio of 95/5: 25 parts, a leveling agent" Modaflow "(trade name, manufactured by Monsanto): 0.2 part,
And xylene, butyl cellosolve acetate, 1-butanol and aromatic petroleum derivative "Swazol 1000"
A mixed solvent composed of (trade name of Idemitsu Petrochemical Co., Ltd.): 40 parts of a mixed solvent was used as an intermediate coating material.

[First overcoat base paint a] 39 parts by weight of a mixed resin of a polyester resin "Beccolite M6012- 60" and a melamine resin "Super Beckamine L-117-60" having a solid content ratio of 70/30, Aluminum powder "Aluminum paste 7680N" (trade name, manufactured by Toyo Aluminum): 10 parts, light stabilizer "Tinuvin 328" (trade name, manufactured by Ciba Geigy): 1 part, leveling agent "Modaflow": 0.3 part, settling prevention Agent "Disparon 6900-
20X "(trade name, manufactured by Kusumoto Kasei Co., Ltd.): 0.3 parts, cellulose acetate butyrate" cellulose ester CAB-
551-0.2 "(Eastman product name): 1 part,
And a mixed solvent of toluene, ethyl acetate and 1-butanol: 48 parts, and the resulting mixture was used as a first topcoat base paint a.

[First overcoat base paint b] Acrylic resin "Hitaloid 2464" (trade name, manufactured by Hitachi Chemical Co., Ltd.) and melamine resin "Super Beckamine L-117-60"
Mixed resin having a solid content ratio of 75/25 with: 40 parts,
Aluminum powder “Aluminum paste 7680N”: 10 parts, light stabilizer “Tinuvin 328”: 1 part, leveling agent “Modaflow”: 0.3 parts, sedimentation inhibitor “Dispalon 690”
0-20X ": 0.3 part and a mixed solvent consisting of toluene, ethyl acetate and 1-butanol: 48 parts were mixed to prepare a first base coat b.

[First overcoat base paint c] The solid content ratio of the polyester resin "Beccolite M6012- 60", the acrylic resin "Hitaloid 2464" and the melamine resin "Super-Beckamine L-117-60" was 40/30.
/ 30 mixed resin: 40 parts, aluminum powder "Aluminum paste 7680N": 10 parts, light stabilizer "Tinuvin 32"
8 ": 1 part, leveling agent" Modaflow ": 0.3 part,
Precipitation inhibitor "DISPARON 6900-20X": 0.3
And a mixed solvent of toluene, ethyl acetate and 1-butanol: 48 parts to prepare a first topcoat base coating c.

[First Overcoat Clear Coating a] Polyester resin "Beccolite M6012- 60", melamine resin "Super Beckamine L-117-60", and melamine resin "Cymel 202" (trade name of Mitsui Cyanamid Co.)
Mixed resin with a solid content ratio of 60/20/20 to: 5
0 parts, ultraviolet absorber "Tinuvin 900" (trade name, manufactured by Ciba Geigy): 2 parts, light stabilizer "Tinuvin 328": 1
The first overcoating clear paint a was prepared by mixing 0.3 parts by weight, a leveling agent “Modaflow”: 0.3 part, and a mixed solvent of xylene, 1-butanol and glycol monobutyl ether: 47 parts.

[First overcoat clear paint b] Acrylic resin "Dianal HR584" (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) and melamine resin "Super Beckamine L-117-"
60 "and a melamine resin" CYMEL 202 "having a solid content ratio of 65/25/10: 50 parts, a UV absorber" Tinuvin 900 ": 2 parts, a light stabilizer" Tinuvin 328 ": 1 part, Leveling agent "Modaflow": 0.3
And a mixed solvent composed of xylene, 1-butanol and glycol monobutyl ether: 47 parts, and the mixture was prepared as a first top clear paint b.

[First Overcoat Clear Coating c] A mixture of a polyester resin "Beccolite M6012- 60", an acrylic resin "Dianal HR584", a melamine resin "Super Beckamine L-117-60" and a melamine resin "Symel 202". A mixed resin having a solid content ratio of 35/30/25/10: 50 parts, an ultraviolet absorber "Tinuvin 90
0 ": 2 parts, light stabilizer" Tinuvin 328 ": 1 part, leveling agent" Modaflow ": 0.3 part, and xylene, 1 part
A mixed solvent consisting of butanol and glycol monobutyl ether: 47 parts was prepared and mixed to prepare a first clear coating material c.

[Second Topcoat] Polyester resin "Beccosol 57-1362" (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) and melamine resin "Super Beckamine L-11"
7-60 ": 45 parts, a mixed resin having a solid content ratio of 70/30: 45 parts, carbon black" FW-200 "(trade name, manufactured by Degussa): 2 parts, and a leveling agent" Modaflow ":
0.2 part and mixed solvent consisting of xylene, 1-butanol and aromatic petroleum derivative "Swazol 1000": 5
A paint prepared by mixing three parts was used as a second top coat.

[Second top coat base paint a] Acrylic resin "Acrydic 47-712" (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) and melamine resin "Super Beckamine L"
-117-60 "with a solid content ratio of 80/20: 44 parts, green pigment" Fast Gen Green S "(trade name, manufactured by Dainippon Ink and Chemicals, Inc.): 4 parts, aluminum powder" Aluminum paste " 1109MA "(trade name, manufactured by Toyo Aluminum Co., Ltd.): 2 parts, leveling agent" Modaflow ": 0.1 part.
3 parts and a mixed solvent consisting of xylene, butyl acetate and 1-butanol: 50 parts were mixed to prepare a second paint.
This was a top coat base paint a.

[Second top coat base paint b] Acrylic resin "Acrydic 47-712" (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) and melamine resin "Super Beckamine L"
-117-60 "and a mixed resin having a solid content ratio of 80/20: 40 parts, aluminum powder" Aluminum paste 7680 "
N ": 10 parts, leveling agent" Modaflow ": 0.3
Part, suspending agent "DISPARON 6900-20X":
A second top coat base paint b was prepared by mixing 0.3 part and 50 parts of a mixed solvent consisting of xylene, butyl acetate and 1-butanol.

[Second top clear coating composition] A mixed resin having a solid content ratio of acrylic resin "Dianal HR584" and melamine resin "Uban 20SE-60" (trade name of Mitsui Toatsu Chemicals Co., Ltd.) of 70/30: 50 parts, ultraviolet absorber "Tinuvin 900": 2 parts, light stabilizer "Tinuvin 3"
28 ": 1 part, leveling agent" Modaflow ": 0.3
And a mixed solvent of glycol monobutyl ether, 1-butanol and an aromatic petroleum derivative “Swazol 1000”: 47 parts, and the resulting mixture was used as a second top clear paint.

The method for adjusting the viscosity of the paint used in the examples and comparative examples is as follows. (Intermediate coating) The above intermediate coating was treated with a mixed solvent of xylene and methyl ethyl ketone for 25 seconds (Ford Cup N
o.4, 20 ° C). (First overcoat base paint) The first overcoat base paint a, b
Alternatively, c was adjusted to 25 seconds (Ford Cup No. 3, 20 ° C.) with a mixed solvent consisting of toluene and ethyl acetate. (First Overcoat Clear Coating) The first overcoat clear coating a, b or c was adjusted with a mixed solvent consisting of butyl acetate and an aromatic petroleum derivative “Swazol 1000” for 20 seconds (Ford Cup No. 3, 20 ° C.). did. (Second Topcoat) The second topcoat was adjusted to 26 seconds (Ford Cup No. 4, 20 ° C.) with a mixed solvent comprising xylene and an aromatic petroleum derivative “Swazol 1000”. (Second topcoat base paint) The second topcoat base paint a or b is mixed with a mixed solvent consisting of toluene and ethyl acetate.
Seconds (Ford Cup No. 3, 20 ° C.). (Second top clear coating) The second top clear coating was prepared by adding 1-butanol and an aromatic petroleum derivative "Swazol 10".
00 ”for 25 seconds (Ford Cup N
o.4, 20 ° C).

Example 1 The intermediate coating composition adjusted as described above was applied to the electrodeposited coating film of kaotin with a “micro mini-bell type coating gun” (trade name, manufactured by Ransburg Japan) to form an intermediate coating film of 10 to 30 μm. After painting and leaving the flash time for 5 minutes, the first top coat base paint a adjusted as described above is applied to a necessary part of the intermediate coat film on the design in the "REA Auto Gun" or the hand spray gun "Wider 71" (Iwata). Painted to a first overcoat base coat of 15 to 20 μm by the trade name of Coating Machine Co., Ltd. (except for the above-mentioned necessary parts, the first overcoat base paint adhered in the form of dust and did not become a coating film. After a flash time of 3 minutes, the first overcoat clear coating a adjusted as described above is coated on the first overcoat base coating film using a “micro minibell type coating gun”. After the painting as to become the first clear top coating of 20~30μm, placed for 7 minutes setting time by, 150
Baking drying was performed at 20 ° C. for 20 minutes. Then the first
Masking is performed on a design-required portion on the top coat clear film, and a second top coat prepared as described above is coated on the surface to be coated other than the masked portion with a "micro mini bell type coating gun" of 35 to 40 μm. After applying the coating so as to become the second top coat and leaving a setting time of 7 minutes,
Baking and drying were performed at 150 ° C. for 20 minutes. Thereafter, the masking was peeled off to obtain a two-tone design film.
This coating process is as shown in FIG.

Example 2 The intermediate coat, the first base coat base coat a, and the first clear top coat c, which were adjusted as described above, were applied in the same manner as in Example 1, dried by baking, and then subjected to the first clear top coat. Masking is performed on a design-required portion of the coating, and the second top-coating base paint a adjusted as described above is applied to the surface to be coated other than the masked portion by a “REA auto gun”.
Paint to a second topcoat base coat of 5-20 μm,
After a flash time of 5 minutes, the second topcoat clear coating prepared as described above was applied to the second topcoat base coat by a "micro minibell type coating gun" for 25 to 30 µm.
m and a setting time of 7 minutes, followed by baking and drying at 150 ° C. for 20 minutes. Thereafter, the masking was peeled off to form a two-tone design film. This coating process is as shown in FIG.

Example 3 The same coating as in Example 1 was carried out using the first topcoat base paint b in place of the first topcoat base paint a to form a two-tone design film. This coating process is as shown in FIG. Example 4 The same coating as in Example 2 was performed using the first topcoat base paint b in place of the first topcoat basecoat a, and using the first topcoat clearcoat a instead of the first topcoat clearcoat c. , A two-tone design film was formed. This coating process is as shown in FIG.

Example 5 A coating having a two-tone design was formed in the same manner as in Example 4 except that the first clear top paint a was used in place of the first clear clear paint a. This coating process is as shown in FIG. Example 6 The same coating as in Example 1 was performed using the first topcoat base paint c in place of the first topcoat base paint a, to form a two-tone design film. This coating process is as shown in FIG.

Example 7 The same coating as in Example 5 was carried out using the first top coat base paint c instead of the first top coat base paint b, to form a two-tone design film. This step is as shown in FIG. Example 8 The same coating as in Example 4 was carried out using the first topcoat base paint c in place of the first topcoat base paint b to form a two-tone design film. This step is as shown in FIG.

Example 9 The same coating as in Example 6 was carried out using the first top clear coating material c in place of the first top clear coating material a, to form a two-tone coating having a design. This step is as shown in FIG. Example 10 The same coating as in Example 2 was carried out using the first topcoat base paint c in place of the first topcoat base paint a to form a two-tone design film. This step is as shown in FIG.

COMPARATIVE EXAMPLE 1 The intermediate coating composition prepared as described above was coated on the cationic electrodeposition coating film by a "micro mini bell type coating gun" to a thickness of 25 to 35 μm.
After a setting time of 7 minutes, the film was baked and dried at 150 ° C. for 20 minutes. Thereafter, the second topcoat base paint a adjusted as described above was applied by a “REA auto gun” so as to form a coating film of 15 to 20 μm, and after a flash time of 5 minutes, the second topcoat clear paint was applied to “Micro Mini Bell Type Paint Gun "
Was applied to form a coating film having a thickness of 25 to 30 μm, and after a setting time of 7 minutes, baking and drying were performed at 150 ° C. for 20 minutes. Thereafter, masking is applied to portions other than the necessary portions on the design, and the second topcoat base paint b adjusted as described above is applied to the necessary portions on the design using a “REA auto gun” to form a 15 to 20 μm coating film. After a flash time of 5 minutes, the second clear top paint adjusted as described above was applied using a "micro mini bell type coating gun" to a coating thickness of 25 to 30 [mu] m.
After a setting time of 150 minutes, baking and drying were performed at 150 ° C. for 20 minutes. Thereafter, the masking was peeled off to form a two-tone design film. This coating process is as shown in FIG.

COMPARATIVE EXAMPLE 2 The intermediate coating composition prepared as described above was coated on a cationic electrodeposition coating film with a "micro mini bell type coating gun" at 25 to 35 μm.
After a setting time of 7 minutes, the film was baked and dried at 150 ° C. for 20 minutes. Thereafter, the second topcoat base paint b adjusted as described above was applied by a “REA auto gun” so as to form a coating film of 15 to 20 μm, and after a flash time of 5 minutes, the second topcoat clear paint was applied to “Micro Mini Bell Type Paint Gun "
Was applied to form a coating film having a thickness of 25 to 30 μm, and after a setting time of 7 minutes, baking and drying were performed at 150 ° C. for 20 minutes. Thereafter, masking is performed on a necessary portion on the design, and the second top coating material adjusted as described above is applied to a portion other than the masked portion into a coating film of 35 to 40 μm using a “micro mini bell type coating gun”. After 7 minutes setting time,
Baking and drying were performed at 20 ° C. for 20 minutes. Thereafter, the masking was peeled off to form a two-tone design film.
This coating process is as shown in FIG.

Coating Test The appearance, chipping resistance and interlayer adhesion of the coatings obtained in Examples 1 to 10 and Comparative Examples 1 and 2 were evaluated according to the following methods. The results were as shown in Table 1. <Test method> Appearance: Visual judgment ◎: Good ：: Almost good ：: Good, but slightly round skin ：: Large round skin ×: Poor

Chipping resistance: 1 k using a gravelometer (manufactured by Q Panel Co., Ltd.) and 1 k roto finish (Nippon Roto Finish Co., Ltd .: Chips CAT-10 × 8)
g is sprayed at an air pressure of 400 KPa and evaluated by the size and number of the peeled area of the coating film of the test piece after the spraying: ：: no peeling ：: slight peeling △: partial peeling (1-2 mm per spot) ² within) ▲: peeling in places (1 2 to 3 mm ² within per places) ×: noticeable peeling

Interlayer adhesion: A test piece was cut into a grid at intervals of 2 mm, a cellophane adhesive tape was stuck on the grid, and the state of peeling of the coating film when completely peeled off was visually judged: ◎: completely No peeling occurs. ○: Chipping is found at the corner but no peeling along the straight line. ◇: Chipping at the corner is seen as a whole but no peeling along the straight line. △: Peeling is slightly seen along the straight line. ▲ : Peeling area within 20% ×: Peeling occurs on the entire surface

[0054]

[Table 1]

As is clear from FIGS. 1 to 3, the number of baking steps in the present invention (Examples 1 to 10) is smaller than that in the conventional two-ton coating step (Comparative Examples 1 and 2). Nevertheless, as is clear from Table 1, a two-tone design film superior to the conventional one could be formed.

If the number of baking steps is large, the coatings of the undercoat, the intermediate coating and the top coating applied first time are hard,
Although it becomes brittle, chipping resistance, interlayer adhesion etc. are inferior,
In the coating step in the present invention (Examples 1 to 4), favorable results were obtained in chipping resistance and interlayer adhesion.

[0057]

The coating film formed by the method for forming a coating film of the present invention can have a design property such as two-tone coating or stripe coating even though the number of baking steps is smaller than in the prior art. The chipping resistance and peeping resistance are superior to those of the conventional coating process.

[Brief description of the drawings]

FIG. 1 is a drawing showing a coating process according to an embodiment of the present invention.

FIG. 2 is a drawing showing a coating process according to an embodiment of the present invention.

FIG. 3 is a drawing showing a coating process according to an embodiment of the prior art.

FIG. 4 is a coating process diagram showing one embodiment of the prior art.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI B05D 7/24 302 B05D 7/24 302P 302S 302V (56) References JP-A-60-48171 (JP, A) JP-A-61 -129068 (JP, A) JP-A-61-153176 (JP, A) JP-A-61-230770 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) B05D 1/00- 7/26

Claims (2)

(57) [Claims] (1) a step of applying an undercoat on a metal plate to form an undercoat; (2) a step of baking and curing the undercoat; and (3) a step of applying the undercoat on the cured undercoat. A mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin as a binder, and applying an intermediate coating containing a coloring pigment to apply the intermediate coating. A step of forming a coating, (4) a mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a polyester resin at a required position on the intermediate coating film without curing the intermediate coating film A mixed resin comprising an acrylic resin and a melamine resin as a binder, and applying a first overcoat base paint containing a color pigment; A step of forming a first overcoat base film, (5) a mixed resin of a polyester resin and a melamine resin, and an acrylic resin on the first overcoat base film without curing the intermediate coat and the first overcoat base film Forming a first clear top coat by applying a first clear clear coat made of a mixed resin of melamine resin and a mixed resin of polyester resin, acrylic resin and melamine resin, (6) the intermediate coat, Baking and curing the first topcoat base film and the first clearcoat film; (7) masking a required portion on the cured first topcoat clear film with a masking material; and (8) masking the masked material. On the surface to be coated other than the part where the resin is present, mixed resin consisting of polyester resin and melamine resin, acrylic resin and melamine resin. A mixed resin consisting of a polyester resin, an acrylic resin and a melamine resin is used as a binder and contains a coloring pigment, but a second top coat of a color different from the first top coat base paint is applied to form a second top coat. A method of forming a coating, (9) a step of baking and curing the entire painted surface, and (10) a step of removing the masking material. (2) a step of applying an undercoat paint on a metal plate to form an undercoat film, (2) a step of baking and curing the undercoat film, and (3) a step of: A mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a mixed resin composed of a polyester resin, an acrylic resin and a melamine resin as a binder, and applying an intermediate coating containing a coloring pigment to apply the intermediate coating. A step of forming a coating, (4) a mixed resin composed of a polyester resin and a melamine resin, a mixed resin composed of an acrylic resin and a melamine resin, or a polyester resin at a required position on the intermediate coating film without curing the intermediate coating film First overcoat base paint containing a brilliant pigment and a coloring pigment using a mixed resin composed of acrylic resin and melamine resin as a binder Forming a first overcoat base film by applying the first overcoat base film without curing the intermediate coat film and the first overcoat base film.
A mixed resin comprising a polyester resin and a melamine resin,
A step of applying a first overcoat clear coating made of a mixed resin of an acrylic resin and a melamine resin or a mixed resin of a polyester resin, an acrylic resin and a melamine resin to form a first overcoat clear coating; (6) the intermediate coating Baking the first overcoat base film and the first overcoat clear film and curing them; (7) masking a required portion on the cured first overcoat clear film with a masking material; and (8) the masking. On the surface to be coated other than the part to be coated, a mixed resin composed of polyester resin and melamine resin, a mixed resin composed of acrylic resin and melamine resin, or a mixed resin composed of polyester resin, acrylic resin and melamine resin as a binder, Pigments,
A step of forming a second topcoat base coat by applying a second topcoat basecoat having a color different from that of the first topcoat basecoat, containing a color pigment, (9) without curing the second topcoat basecoat A second overcoat clear coating comprising a mixed resin comprising a polyester resin and a melamine resin, a mixed resin comprising an acrylic resin and a melamine resin, or a mixed resin comprising a polyester resin, an acrylic resin and a melamine resin on the second topcoat base film Coating to form a second overcoat clear coating, (10) a step of baking and curing the entire coated surface, and (11) a step of removing the masking material. Method of forming.