JP2001314812A - Method for forming multilayer coating film with multicolor trait - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a multilayer coating film with a multicolor trait by which it is possible to obtain a coating film which is free from color irregularities and develops a multicolor trait and further, can be easily repaired. SOLUTION: This method for forming a multilayer coating film with a multicolor trait includes (1) a process to form a first coating film by applying a first coating material containing a brilliant material to the surface of an object to be coated, (2) a process to form a second coating film by applying a second coating material containing 1-7 wt.% titanium particles for the resin solid content of the coating material to the surface of first coating film without baking and curing the first coating film, and (3) a process to form a clear coating film by applying a clear coating material to the surface of the second coating film without baking and curing the second coating film.

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 multilayer coating film, and more particularly to a method for forming a multicolor multilayer coating film.

[0002]

2. Description of the Related Art In general, a coating film is formed on the surface of an automobile body, electric equipment and parts thereof from the viewpoints of aesthetic appearance and imparting various functions.

[0003] As a method of forming such a coating film, specifically, a colored paint is applied to the surface of a substrate having an electrodeposition coating film and / or an intermediate coating film formed on a substrate. After forming the colored coating film, a method of forming a multilayer coating film by further applying a clear paint to form a clear coating film, and simultaneously heating and curing the coating film, may be mentioned.

[0004] In recent years, a paint color called silver pearl has attracted attention as a paint color having high design properties. This coating color is different from the color when the coating film is viewed vertically (highlight) and the color when the coating film is viewed obliquely (shade), and is a coating color capable of expressing so-called polychromaticity. is there. Such a coating film is a multilayer coating film in which an aluminum pigment-containing coating film, an interference mica-containing coating film, and a clear coating film are sequentially provided on an object to be coated.

[0005] However, the multilayer coating film thus obtained tends to cause unevenness depending on the conditions for forming the aluminum pigment-containing coating film and the interference mica-containing coating film, making it difficult to obtain uniform polychromaticity. There was a case. In addition, it was difficult to restore the multicolor property of the multilayer coating film obtained as described above to its original state by repair.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a multicolored multi-layered coating film which can exhibit uniform polychromaticity without color unevenness in the obtained coating film and can be easily repaired. The aim is to provide a method.

[0007]

According to the present invention, there is provided (1) a step of applying a first paint containing a glittering material to a surface of an object to be coated to form a first coating film; (1) a step of applying a second paint containing titanium particles thereon without baking and curing the coating film to form a second coating film; (3) further baking and curing the second coating film A method for forming a multilayer coating film including a step of applying a clear coating material thereon to form a clear coating film, wherein the content of the titanium particles in the second coating material is reduced to the resin solid content in the coating material. The method for forming a multicolored multi-layer coating film is 1 to 7% by weight. Here, the average particle diameter of the titanium particles is 0.01 to 0.08 μm.
m is preferable. Here, the glitter material in the first paint is preferably an aluminum pigment, and its content is preferably 1 to 20% by weight based on the resin solid content in the paint. Further, it is preferable that the clear paint does not contain a coloring component and a glittering material.

Here, an electrodeposition coating film and / or an intermediate coating film is formed on the surface of the object to be coated in advance.

Further, the present invention is a polychromatic multilayer coating film obtained by the above-mentioned method for forming a polychromatic multilayer coating film.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The method for forming a multicolored multilayer coating film of the present invention comprises the steps of: (1) applying a first coating material containing a brilliant material to the surface of an object to be coated; Forming step (2)
A step of applying a second paint containing titanium particles on the first coat without baking and curing the first coat to form a second coat; (3) further forming the second coat A multilayer coating film forming method comprising a step of forming a clear coating film by applying a clear coating material containing no coloring component thereon without baking and curing, wherein the content of titanium particles in the second coating material is reduced. It is characterized in that it is 1 to 7% by weight with respect to the resin solid content in the paint.

First Paint The first paint used in the method of forming a multicolored multilayer coating film of the present invention may be any of a curable paint and a dry paint.
It contains a film-forming component and a glittering material.

Examples of the film-forming component include resin components such as acrylic resin, polyester resin, epoxy resin and urethane resin. When the first paint is a curable paint, for example, the resin component having a curing functional group and the curing of an amino resin or an optionally blocked isocyanate resin or the like corresponding to these functional groups. A combination with an agent can be exemplified.

Examples of the brilliant include the above-mentioned aluminum powder, alumina powder, bronze powder, copper powder, tin powder, zinc powder, iron phosphide, metal-coated mica powder, and titanium dioxide-coated mica powder. be able to. The content of the glitter material in the first paint is preferably 1 to 20% by weight based on the resin solid content in the paint. If the content is less than 1% by weight, the resulting multi-layer coating film may have insufficient polychromaticity. If the content is more than 20% by weight, the corresponding effect may not be obtained, which may not be economical. is there. Here, the resin solid content in the coating material in the present invention refers to the solid content weight of the film-forming component.

The first paint used in the method for forming a multicolored multilayer coating film of the present invention may contain a coloring component in addition to the above components. Examples of the coloring component include, for example, inorganic coloring pigments such as titanium dioxide, carbon black, iron oxide, and yellow iron oxide, phthalocyanine blue, phthalocyanine green, carbazole violet, anthrapyridine, azo orange, flavanthrone yellow, isoindoline yellow, and azo. Yellow, Indathrone Blue, Dibromo Anzathrone Red, Perylene Red, Azo Red,
Dyes such as 1: 2 chromium complex black, 1: 2 chromium complex yellow, and 1: 2 cobalt complex yellow such as organic color pigments such as anthraquinone red and quinacridone red can be exemplified.

When the first paint contains a coloring component, the content of the brilliant material and the coloring component is determined from the viewpoint of design.
The content is preferably 1 to 60% by weight based on the resin solid content in the paint.

The first paint may further contain resin particles. By including the resin particles, the viscosity of the coating film at the time of coating and after the coating can be controlled. For example, in step (2) described below, adaptation or inversion between the first coating film and the second coating film is performed. Can be suppressed. The resin particles are not particularly limited, and are obtained, for example, by polymerizing an ethylenically unsaturated monomer in the presence of a polyester resin or an alkyd resin having a portion insoluble in an organic solvent and an insoluble portion in an organic medium. Examples thereof include acrylic resin particles called NAD particles and acrylic resin particles obtained by emulsion-polymerizing an ethylenically unsaturated monomer in an aqueous medium in the presence of a surfactant. These resin particles may be crosslinked resin particles or non-crosslinked resin particles. The average particle size of the resin particles is preferably from 20 to 500 nm from the viewpoint of storage stability. The content of the resin particles in the first paint is usually 1 to 20% by weight based on the resin solid content in the paint.

The first coating material may contain, if necessary, those well known to those skilled in the art, such as extenders, curing catalysts, surface preparation agents, ultraviolet absorbers, antioxidants, and the like.

The form of the first coating material is not particularly limited, and may be any of a solvent type, a water dispersion type and a water type.

Second paint The second paint used in the method for forming a multicolored multilayer coating film of the present invention may be either a curable paint or a dry paint.
It contains a film-forming component and titanium particles. Specific examples of the film-forming component include those described for the first paint.

From the viewpoint of the appearance of the obtained multilayer coating film, the titanium particles have an average particle diameter of 0.01 to 0.08.
μm, more preferably 0.03 to 0.05 μm. Such titanium particles,
Examples of commercially available titanium dioxide used as a pigment include Typek TTO-55 (titanium particles, average particle diameter 0.04 μm, manufactured by Ishihara Sangyo Co., Ltd.).

The content of the titanium particles in the second paint is 1 to 7% by weight based on the solid content of the resin in the paint.
Preferably it is 2 to 5% by weight. When the content is less than 1% by weight, the obtained multilayer coating film has insufficient polychromaticity, and when it exceeds 7% by weight, the resulting multilayer coating film cannot have a clear feeling, It is not economical because there is no corresponding effect.

The second paint may further contain a coloring component. Specific examples of the coloring component include those described for the first coating material other than the titanium particles. The content of the coloring component in the second paint is preferably 1% by weight or less based on the resin solid content in the paint. If the content exceeds 1% by weight, the resulting multilayer coating may have insufficient polychromaticity.

The second paint used in the method for forming a multicolored multilayer coating film of the present invention preferably does not contain a glittering material from the viewpoint of preventing color unevenness of the obtained coating film and repairability.

The second paint can further contain resin particles. Specific examples of the content of the resin particles in the resin particles and the content of the resin particles in the second coating material include those described in the first coating material.

The second coating material may include, if necessary, those well known by those skilled in the art, such as an extender pigment, a curing catalyst, a surface preparation agent, an ultraviolet absorber, and an antioxidant.

The form of the second paint is not particularly limited, and may be any of a solvent type, a water dispersion type and a water type.

Clear Paint The clear paint used in the method for forming a multicolored multilayer coating film of the present invention is preferably a curable clear paint from the viewpoint of the performance of the obtained coating film. The curable clear coating composition contains a cured film-forming component. Examples of the cured coating film-forming component include a combination of a resin component and a curing agent described in the case where the first coating material is a curable coating material. From the viewpoint of acid resistance, active hydrogen such as a hydroxyl group can be used. A combination of an acrylic resin and / or a polyester resin having a functional group containing a polyisocyanate resin and a curing agent for a blocked polyisocyanate resin, if necessary, or a carboxylic acid group-containing acrylic resin and / or a polyester resin and an epoxy group-containing acrylic The combination with a resin is preferable.

It is preferable that the clear paint does not contain a coloring component and a brilliant material from the viewpoints of color fading, weather resistance and color depth of the obtained coating film, and color unevenness and repairability. Examples of the coloring component and the glittering material include those described for the first paint.

Further, the clear paint used in the method for forming a multicolored multilayer coating film of the present invention comprises a surface conditioner, a viscosity control agent,
Various additives well known by those skilled in the art, such as ultraviolet absorbers and light stabilizers, can be included.

The form of the clear paint is not particularly limited, and may be any of a solvent type, an aqueous dispersion type, an aqueous type and a powder.

The method for forming a multicolored multi-layer coating film The method for forming a multicolor multi-layer coating film of the present invention is for forming on a surface of an object to be coated.

Examples of the object to be coated include iron, steel,
Examples thereof include metals such as aluminum, tin, and zinc, alloys containing these metals, molded products obtained by plating or depositing these metals, and molded products made of glass, plastic, or foam. These objects to be coated are preferably subjected to a degreasing treatment or a surface treatment. Further, an undercoating film or an intermediate coating film may be formed on the surface of the object to be coated. For example, when the object to be coated is an automobile body or a part, an undercoating film or an intermediate coating film is formed on the surface thereof.

The undercoat film is formed to impart concealing properties, anticorrosion properties and rust prevention properties on the surface of the material, and can be obtained by applying the undercoat paint and baking and curing. The thickness of the undercoat film, for example,
10 to 50 μm. The undercoat paint used to form such an undercoat film is not particularly limited, and specific examples thereof include a cationic electrodeposition paint and an anion electrodeposition paint, and specifically, a hydroxyl group-containing paint. Those well-known by those skilled in the art, such as those containing a resin and a blocked polyisocyanate, those containing a resin containing a sulfonium group and a propargyl group, and the like can be exemplified. These are subjected to electrodeposition coating and then baked and cured according to the type of paint used.

The intermediate coating film is formed to impart concealing properties and adhesion to the surface of the object to be coated and the undercoat film, and further to provide chipping resistance. It is formed on a coating film and can be obtained by applying an intermediate coating. The thickness of the intermediate coating film is, for example, 10 to 50 μm. The intermediate coating used to form the intermediate coating contains a film-forming component, for example, a hydroxyl-containing polyester resin and / or a hydroxyl-containing acrylic resin, a melamine resin and / or a blocked polyisocyanate. And those well-known by those skilled in the art, such as those containing These are dried or cured at room temperature or by baking after being applied, depending on the form of the paint used.

<Step (1)> In the step (1) in the method for forming a multicolored multilayer coating film of the present invention, the first paint containing a glittering material is applied to the surface of the object to be coated. First
It forms a coating film. With this first coating film, the color of the surface of the object to be coated is concealed, and in combination with the second coating film and the clear coating film described later, it is possible to express high chroma and a transparent design.

The solid content concentration and viscosity of the applied first paint can be appropriately adjusted by diluting with an organic solvent and / or water. Examples of the method of applying the first paint in the step (1) include air spray coating, airless spray coating, and electrostatic spray coating. From the viewpoint of coating efficiency,
Preference is given to electrostatic spray painting. The coating thickness is not particularly limited, but is usually 5 to 20 μm.

Further, in order to suppress the adaptation and inversion between the layers of the first coating film obtained in the above-mentioned step (1) and the second coating film obtained in the below-mentioned step (2), the above-mentioned step (1) )
After that, before proceeding to the subsequent step (2), it is preferable to perform an operation of opening a time interval called an interval. By this interval, the organic solvent and / or water contained in the first coating film can be sufficiently volatilized,
The appearance of the resulting multilayer coating is improved. The interval is, for example, 15 seconds to 15 minutes. In addition, the first
When the form of the coating material is a water-dispersion type or a water-soluble type, a heating operation called preheating may be performed on the object on which the first coating film is formed during the above interval. By this preheating, the organic solvent and / or water contained in the first coating film can be volatilized efficiently in a short time. This heating operation does not actively cure the first coating film.
2 to 10 minutes at 0 to 80 ° C. The preheat is
For example, it can be performed using a warm air heater or an infrared heater.

<Step (2)> In the step (2) of the method for forming a multicolored multilayer coating film of the present invention, the first coating film obtained in the above step (1) is applied without baking and curing. And the second coating containing titanium particles is applied to form a second coating film. With this second coating film, polychrome can be imparted to the obtained multilayer coating film.

The solid content concentration and the viscosity of the second paint can be appropriately adjusted by diluting the second paint with an organic solvent and / or water.

The coating method and the coating thickness in the step (2) are the same as those described in the step (1).

Further, in order to suppress the adaptation and inversion between the second coating film obtained in the step (2) and the clear coating film obtained in the step (3) described below, the step (2) )
After that, before proceeding to the subsequent step (3), an operation of opening a time interval called an interval, and the coating on which the second coating film is formed during the interval, as in the above step (1). A heating operation called preheating may be performed on the object. The above interval and preheating can be performed in the same manner as in the above step (1).

<Step (3)> In the step (3) in the method for forming a multicolored multilayer coating film of the present invention, the above-mentioned second coating film is further applied without baking and hardening the second coating film. To form a clear coating film. The clear coating prevents color fading of the first coating and the second coating, and can impart high transparency and color depth to the obtained multilayer coating.

In the above step (3), when the clear paint to be applied is a solvent type, a water dispersion type or a water type, the solid content concentration and the viscosity thereof are diluted with an organic solvent and / or water. This can be adjusted as appropriate.

The application method in the above step (3) is not particularly limited, and can be appropriately selected depending on the type and form of the clear coating. Specifically, in the case of a solvent type, an aqueous dispersion type or a water type, , Air spray coating, airless spray coating, electrostatic spray coating and the like, and in the case of powder, powder coating. The coating thickness is not particularly limited, but is usually 30 to 50 μm.

After the above-mentioned steps (1), (2) and (3), for example, by drying or curing at a predetermined temperature for a predetermined time, a high-design multi-layer coating film can be obtained on the surface of the object to be coated. it can. The predetermined temperature and the predetermined time are as follows:
It can be set appropriately according to the type of the clear paint.

Multicolored Multilayer Coating The multicolored multilayer coating of the present invention is obtained by the above-mentioned method for forming a multicolored multilayer coating, has different colors for highlight and shade, and , Having a transparent feeling. The above-mentioned multicolor coating film contains a first material containing a glittering material.
It comprises a coating film, a second coating film containing titanium particles, and a clear coating film. The first coating film, the second coating film, and the clear coating film are obtained by using the first coating material, the second coating material, and the clear coating material described in the multicolor multilayer coating film forming method.

[0047]

EXAMPLES Production Examples 1-4 First paints A-C and second paint
Based on the formulation of the preparation Table 1 fee, raw material uniformly dispersed mixed, first paint A~C of metallic paint colors, and to obtain a second coating material containing titanium particles.

Production Example 5 Preparation of clear paint 100.00 parts by weight of a carboxylic acid group-containing thermosetting acrylic resin (acid value: 137, number average molecular weight: 3000, styrene / cyclohexyl methacrylate / isobutyl acrylate / maleic anhydride = 30 / 23/23/24, acrylic resin obtained by half-esterifying maleic anhydride with methanol after copolymerization, solid content 50% by weight) Epoxy and hydroxyl group-containing thermosetting acrylic resin 82.00 parts by weight (hydroxyl value 46, Epoxy equivalent 420, number average molecular weight 3400, solid content 61% by weight) Tetrabutylammonium bromide 0.30 part by weight Silicon-based surface conditioner 0.10 part by weight Crosslinked acrylic resin particles 10.00 part by weight (average particle diameter 55 nm, solid 25% by weight) The above-mentioned raw materials are converted into carboxylic acid groups and epoxy groups. Is 1
/ 1 and uniformly dispersed to obtain a clear paint having a paint solid content of 53% by weight.

Production Example 6 Preparation of an object to be coated A Powertop U-50 (cationic electrodeposition paint manufactured by Nippon Paint Co., Ltd.) was applied to a 300 × 400 × 0.8 mm dull steel plate treated with zinc phosphate and dried. Electrodeposition was applied so as to have a thickness of 20 μm, and baked and cured at 160 ° C. for 30 minutes.
Next, Olga P-2 gray (melamine curable polyester resin intermediate coating paint, gray color, manufactured by Nippon Paint Co., Ltd.) was spray-coated on the obtained electrodeposition coating film so as to have a dry film thickness of 30 μm. After setting for 10 minutes, 14
The coating was baked and cured at 0 ° C. for 20 minutes to form an intermediate coating film on the surface of the object to be coated.

Example 1 Ethyl acetate: butyl acetate: xylene: sorbets # 100 (aromatic solvent manufactured by Esso): cellosolve acetate = 30 in advance on the surface of the object to be coated obtained in Production Example 6.
Using a diluting solvent obtained by mixing at a ratio of 10: 30: 20: 10 (weight ratio), a # 3 Ford cup was used for 18 seconds (20%).
° C) and the first coating material A obtained in Production Example 1 was sprayed with air so as to have a dry film thickness of 9 µm to obtain a first coating film. After setting for 90 seconds, the second paint obtained in Production Example 4, which was similarly diluted, was
The second coating film was obtained by air spray coating on the first coating film so that the dry film thickness became 9 μm. After setting for 4 minutes, Solvents # 100 (aromatic solvent manufactured by Esso): Solvets # 150 (aromatic solvent manufactured by Esso): diethylene glycol monobutyl ether = 3
Using the diluting solvent obtained by mixing at a ratio of 6: 55: 9 (weight ratio), the clear paint of Production Example 5 diluted to 20 seconds (20 ° C.) with a # 4 Ford cup was dried. Spray coating on the second coating so that the thickness becomes 35 μm,
After further setting for 7 minutes, the film was baked and cured at 140 ° C. for 20 minutes to obtain a polychromatic multilayer coating film 1.

Examples 2 and 3 Except that the first paint A of Production Example 1 was replaced with the first paint B of Production Example 2 and the first paint C of Production Example 1, respectively. In the same manner as in Example 1, polychromatic multilayer coating films 2 and 3 were obtained.

Evaluation Tests The following items were tested for the multicolored multilayer coating films 1 to 3 obtained in Examples 1 to 3. The results are shown in Table 2.

<Chromaticity Measurement> For each coating film, a goniospectroscopic colorimetric system GCMS-WIN Rel. 1.00.04
The chromaticity was measured at 40 degrees and -80 degrees with respect to 45 degrees of incident light using a (variable color difference meter manufactured by Murakami Color Research Laboratory).

<Color and Transparency> Each coating film was visually evaluated for highlight and shade colors and highlight transparency.

[0055]

[Table 1]

[0056]

[Table 2]

As is clear from Table 2, the multilayer coating film obtained by the method of forming a multicolor multilayer coating film of the present invention exhibited different colors between highlight and shade. Also, the transparency was excellent.

[0058]

According to the multilayer coating film obtained by the method for forming a multicolor multilayer coating film of the present invention, the first coating material contains a glittering material, the second coating material contains titanium particles, and the content is reduced. Since it is defined, a so-called polychromaticity in which the paint color differs depending on the viewing angle can be exhibited. Further, according to the method of forming a multicolored multi-layer coating film of the present invention, since the second paint does not need to contain a glitter, the occurrence of color unevenness due to the glitter contained in the second paint is suppressed. be able to.

Further, repair of the multilayer coating film, which has been difficult until now, can be easily performed because the second paint does not contain a glittering material.

Claims (7)

[Claims] 1. A step of (1) applying a first paint containing a glitter material to a surface of an object to be coated to form a first coating film, and (2) baking and curing the first coating film. Instead, a second paint containing titanium particles is applied thereon to form a second paint.
A step of forming a coating film, and (3) further comprising a step of applying a clear paint on the second coating film without baking and curing the second coating film to form a clear coating film. A method for forming a multicolor multilayer coating film, wherein the content of titanium particles in the second coating material is 1 to 7% by weight based on the resin solid content in the coating material. 2. The titanium particles have an average particle diameter of 0.01 to 0.01.
The method according to claim 1, wherein the thickness is 0.08 µm. 3. The method according to claim 1, wherein the glitter material in the first paint is an aluminum pigment. 4. The method according to claim 1, wherein the content of the brilliant material in the first paint is
The method for forming a multicolored multilayer coating film according to any one of claims 1 to 3, wherein the amount is 1 to 20% by weight based on a resin solid content in the coating material. 5. The method according to claim 1, wherein the clear coating material does not contain a coloring component and a glittering material. 6. The method according to claim 1, wherein the surface of the object to be coated has an electrodeposition coating
The method for forming a multicolored multilayer coating film according to any one of claims 1 to 5, wherein an intermediate coating film is formed. 7. A multicolored multilayer coating film obtained by the method for forming a multicolored multilayer coating film according to any one of claims 1 to 6.