JPH10298458A - Brilliant pigment-containing coating composition and formation of composite coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a composite coating film for an automobile which exhibits a high brilliancy not seen before and has a noble design, by utilizing an alumina flake which tends to give prominence to some inconsistencies due to its high brilliancy as a brilliant pigment for a metallic coating material being capable of forming a film which has an excellent appearance and no inconsistencies. SOLUTION: A brilliant pigment-containing coating composition comprising an alumina flake and a viscosity-controlling agent as a coating composition for forming a coating film layer containing a brilliant pigment is coated by using a 2 coating-1 baking process, optionally by a 2 coating-2 baking or 2 coating-3 baking process to form a composite coating film, thereby providing a coating film having an excellent design not seen before.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glitter pigment-containing coating composition containing alumina flakes, and a composite using the glitter pigment-containing coating composition, which can be suitably used as a thermosetting coating, especially as a top coating for automobiles. The present invention relates to a method for forming a coating film, a composite coating film formed by the method, and an article having the composite coating film.

[0002]

2. Description of the Related Art As a top coating for automobiles, a coating containing a brilliant pigment called a metallic paint containing a brilliant pigment such as metal powder and / or mica is generally known. Among such brilliant pigments, a metallic paint containing aluminum powder or mica powder coated with a metal oxide changes the amount of reflected light depending on the viewing angle, and has high design properties.

Among the items for evaluating the design properties of metallic paints, the glitter is greatly affected by the particle size and shape of the glitter pigment itself. Therefore, in order to enhance the glitter of the metallic coating, study of the glitter pigment itself,
Various studies have been made on a coating film forming method that leads to higher design properties. Also, in the case of a conventional glitter pigment,
When used in combination with other glittering pigments or coloring pigments, the glittering feeling is buried and less noticeable.

[0004]

DISCLOSURE OF THE INVENTION The present invention uses alumina flakes, which are easy to notice unevenness due to strong glitter, as glitter pigments for metallic paints capable of forming coatings with high appearance and no unevenness. An object of the present invention is to form a composite coating film for automobiles having an unprecedented brilliant feeling and a novel design.

[0005]

Means for Solving the Problems The present inventors prepared a coating composition containing a glittering pigment containing alumina flakes and a viscosity controlling agent in two coats and one bake, and three coats in two coats if necessary.
It has been clarified that by applying a bake or a three-coat one-bake process to form a composite coating film, a coating film having an unprecedented design property can be provided, and the above problem can be solved.

That is, the present invention provides [1] a glitter-containing coating composition containing alumina flakes as a glitter pigment and a viscosity controlling agent. [2] A method for forming a composite coating film on an undercoated base material in two coats and one bake, wherein the first layer is formed from the bright pigment-containing coating composition of the present invention. Forming method. [3] a method of forming a composite coating film on the undercoated base material by 3 coats 2 bake or 3 coats 1 bake,
A method for forming a composite coating film, wherein the second layer is formed from the bright pigment-containing coating composition of the present invention. [4] a composite coating film formed by the above method. And [5] an article having the composite coating film. Is provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Alumina flake, which is a glitter pigment used in the present invention, is made of aluminum oxide (Al2O3).
3) is coated with a metal oxide such as titanium dioxide.
It has a particle size of 10 to 30 μm and a thickness of 0.3 to 0.4 μm. In addition, light scattering by fine particles is small due to high surface smoothness and sharp particle size distribution. Furthermore, since the surface of the flaky alumina crystal with a high aspect ratio is coated with a metal oxide, it becomes a pearly pigment, and when it is formed into a coating film, it can be obtained with conventional mica powder from both the highlight and shade positions. A coating film having a strong shine that could not be obtained is obtained, has a transparent appearance, and can express a three-dimensional impression.

[0008] As the above alumina flake, for example, “SD” sold by Merck Japan K.K.
A-SILVER W-3 (trade name) "and the like. These are metal oxides (Al2O3,
By changing the species and amount of TiO2, SnO2, ZrO2, Fe2O3, etc., it is possible to cover from silver color to copper color, sienna color interference color, and it is possible to obtain higher brightness by using the composite coating film forming method of the present invention. When exposed to strong light such as sunlight, a coating film having a paint color having a particularly strong glitter can be provided.

Alumina flake content (PWC%)
Is from 0.01% to 15.0%, and when the ratio exceeds the upper limit, the appearance of the coating film is reduced, and when the ratio is lower than the lower limit, the glitter is reduced. Preferably, it is 0.1% to 14.0%, more preferably 1% to 13.0%.

In the present invention, it is preferable that the above-mentioned alumina flakes are used alone as the glitter pigment in terms of design. However, when the above-mentioned alumina flakes are used as the glitter pigment, it is possible to provide a coating film having a strong shine and transparency that cannot be obtained with conventional mica powder from both the highlight and shade positions.

Depending on the coating color, other glittering pigments can be used in combination. Other glitter pigments that can be used in combination
Aluminum powder or mica powder coated with a metal oxide such as titanium dioxide or iron oxide is generally used, but other flat pigments having glitter may also be used. In addition, organic
Inorganic color pigments or extender pigments can be used in combination with the alumina flakes.

The total pigment concentration (PWC%) in the paint when a pigment other than alumina flake is used in combination is 0.1%
To 80%, preferably 0.5% to 70%, and more preferably 1.0% to 60%. If it exceeds the upper limit, the appearance of the coating film will be reduced.

The glitter pigment-containing coating composition of the present invention contains a viscosity controlling agent. The viscosity controlling agent is used for forming a good and uniform coating film. As the viscosity controlling agent, those having a thixotropic property can be generally used as an "anti-sagging agent". Examples of such a material include swelling dispersions of fatty acid amides, amide-based fatty acids, polyamides such as phosphates of long-chain polyaminoamides, and polyethylene-based materials such as colloidal swelling dispersions of polyethylene oxide. is there.

In addition, there are organic bentonites such as organic acid smetite clay and montmorillonite, inorganic pigments such as aluminum silicate and barium sulfate, flat pigments which exhibit viscosity depending on the shape of the pigments, and mutual interaction between polar groups. Non-crosslinked or crosslinked resins or particles utilizing the action can be cited as viscosity control agents. In the present invention, the viscosity control agent may be used alone, but may be used in combination.

However, those which do not affect the gloss and the color development when formed into a coating film are preferable, and among the above-mentioned viscosity control agents, crosslinkable resin particles are particularly preferable. Such crosslinkable resin particles are insoluble in the organic solvent used in the coating composition of the present invention and have an average particle size of 0.02 to 0.5 μm.
Is preferable. If the upper limit is exceeded, the stability will decrease. The above crosslinkable resin particles are obtained by synthesizing a monomer having a zwitterionic group in the molecule as one of the polyhydric alcohol components, a resin having an emulsifying ability such as an alkyd resin or a polyester resin, and a polymerization initiator. Those obtained by emulsion polymerization of an ethylenically unsaturated monomer in an aqueous medium in the presence are preferred.

The monomer having a zwitterionic group in the molecule includes -N (+)-R-COO (-) or -N (+)-
Those represented as R-SO3 (-) and having two or more hydroxyl groups can be used. As such a monomer, a hydroxyl group-containing aminosulfonic acid-type zwitterionic compound is preferable from the viewpoint of resin synthesis. Specific examples include bishydroxyethyl taurine.

The resin having an emulsifying zwitterionic group in the molecule, which is synthesized using the above monomer, has an acid value of 30 to 150 mgKOH / g, preferably 40 to 150 mgKOH / g.
It is preferable to use a polyester resin having a KOH / g and a number average molecular weight of 500 to 5,000, preferably 700 to 3,000. If the upper limit is exceeded, the handling properties of the resin will decrease,
If it is below the lower limit, a resin having an emulsifying ability is desorbed when a coating film is formed, or the solvent resistance is reduced.

In the synthesis of the crosslinkable resin particles, the ethylenically unsaturated monomer to be emulsion-polymerized is a monomer having two or more radically polymerizable ethylenically unsaturated groups in the molecule. Such a monomer having two or more radically polymerizable ethylenically unsaturated groups in the molecule is preferably contained in the range of 0.1 to 10% by weight of all the monomers. The amount is selected to provide sufficient crosslinking to dissolve the particulate polymer in the solvent.

The crosslinkable resin particles used in the present invention are generally contained in an emulsion resin, do not contain a low-molecular emulsifier or a protective colloid which deteriorates the performance when formed into a coating film, and have two or more particles per molecule. Since the polymer is crosslinked by copolymerizing a monomer having a radically polymerizable ethylenically unsaturated group, the coating film is excellent in water resistance, solvent resistance, gloss and the like.

The amount of the viscosity control agent to be added in the present invention is 0.01 to 15 parts by weight, preferably 0.1 to 12 parts by weight, per 100 parts by weight of the resin solid content of the coating composition of the present invention.
Parts by weight, more preferably 0.2 to 9 parts by weight. If the amount of the viscosity control agent exceeds 15 parts by weight,
If the appearance is reduced, and if the amount is less than 0.01 part by weight, the effect of controlling the viscosity cannot be obtained, which may cause adaptation or inversion between layers.

The coating composition of the present invention contains a thermosetting film-forming resin. This resin disperses a glitter pigment and a viscosity control agent to form a cured coating film, and is not particularly limited. Generally, acrylic resin,
Polyester resins, alkyd resins, thermosetting film-forming resins having at least one hydroxyl group selected from the group consisting of epoxy resins and the like can be used, and these can be used in combination with a curing agent such as an amino resin and / or a blocked isocyanate resin. Used. It is preferable to combine an acrylic resin having a hydroxyl group with an amino resin from the viewpoints of weather resistance, pigment dispersibility and coating workability.

The weight composition ratio of the thermosetting film-forming resin and the curing agent in the glitter pigment-containing coating composition of the present invention is 90.
/ 10 to 10/90, preferably 80/20 to 5
0/50. If it exceeds the upper limit, the curability will decrease, and if it falls below the lower limit, the coating will be hard and brittle.

Further, in the glitter pigment-containing coating composition of the present invention, if necessary, a curing catalyst, an ultraviolet absorber, an antioxidant, a surface preparation agent and the like can be used.

The total pigment content of the glitter pigment-containing coating composition of the present invention is from 20 to 70% by weight, preferably from 3 to 70% by weight.
0 to 50% by weight. Exceeding the upper and lower limits lowers the paint stability. At the time of application, it is 10 to 60% by weight, preferably 20 to 50% by weight. If the upper limit is exceeded, the viscosity is too high and the appearance of the coating film is reduced, and if it is lower than the lower limit, the viscosity is too low and poor appearance such as adaptability and unevenness occurs.

The method for producing the coating composition of the present invention is not particularly limited, and any method known to those skilled in the art, such as kneading and dispersing a compound such as a pigment using a kneader or a roll, can be used.

[0026] The coating composition of the present invention can be prepared from any substrate, such as wood, metal, glass, cloth, plastic, foam, etc.
In particular, it can be used advantageously for plastics and metal surfaces, such as steel, aluminum, their alloys and castings, but can be used particularly preferably for cationic electrodepositable metal products.

The above-mentioned 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.

In general, the thickness of a coating film at the time of coating with the glitter pigment-containing coating composition of the present invention varies depending on the desired use, but in many cases, 5 to 40 μm is useful, and more preferably 10 to 25 μm. It is about. If the upper limit is exceeded, problems such as unevenness or flow may occur during coating, and if the lower limit is not reached, the base material cannot be concealed and a film break occurs.

After coating on the base material, the coating film is cured. The cured film is cured at 100 to 180 ° C., preferably 120 to 160 ° C., and has a high degree of crosslinking. 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.
Curing at 10 ° C. for 10 to 30 minutes is suitable.

The coating composition containing a brilliant pigment in the present invention is generally preferably of a solution type, and if it is a solution type, it may be an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), a non-aqueous type. Any of a dispersion type may be used.

When the glitter pigment-containing paint is used as an aqueous paint, US Pat. No. 5,151,125 and US Pat. No. 5,151,125 may be used as a binder for the glitter pigment-containing paint composition.
183, 504 and the like can be used. In particular, US Pat.
The thermosetting film-forming resin obtained by combining the melamine resin with the acrylic resin having an acrylamide group, a hydroxyl group, and an acid group described in No. 3,504 is excellent in finish and appearance performance.

When the glitter pigment-containing coating composition of the present invention is applied to an automobile body, an electrodeposition coating film as a base coat and a cured or uncured intermediate coating film are formed on a chemically treated steel sheet. The coating is preferably performed on the base material by a coating method such as electrostatic coating or air spray. In order to suppress unevenness in glitter, it is more preferable to apply the paint in two stages than in one stage.

Further, a two-coat, one-bake coating method in which a clear coating is applied on an uncured glittering pigment-containing coating film of the present invention by wet-on-wet, and thereafter both coating films are cured, is a point of design. Is preferred.

When the glitter pigment-containing paint is used as a water-based paint, the glitter pigment-containing coating must be coated before coating the clear paint in order to obtain a good finished coating.
It is desirable to heat at １００100 ° C. for 2 to 10 minutes.

Before applying the glitter pigment-containing coating composition of the present invention, the color base layer is formed as a first layer, and the glitter pigment-containing coating layer of the present invention is formed thereon as a second layer. And further forming a clear coating layer thereon 3
The composite coating film formed by the method of forming a composite coating film of two coats or three coats and one bake provides a coating film having a strong glitter and a high designability.

However, in the above-described method for forming a composite coating film, in order to control the so-called “fit-in” between the coating films,
An excellent appearance can be obtained by sequentially controlling the paint viscosity of the clear paint, the bright pigment-containing paint and, if necessary, the color base paint, and controlling the viscosity of each formed coating film interface.

The electrodeposition paint which is applied on a substrate used in the method for forming a composite coating film of the present invention and forms an undercoat layer includes:
Cationic and anionic types can be used, but the cationic electrodeposition coating composition gives a composite coating film having excellent corrosion resistance. Cationic electrodeposition coating composition is a cathodic deposition type thermosetting electrodeposition coating material which is based on a resin having a basic amino group and is made water-soluble by neutralizing with an acid. Painted as cathode.

As the resin having a basic amino group used in the cationic electrodeposition coating composition, a secondary amine (for example, a primary amine is blocked by a ketimination of diethylene triamine or the like) to an epoxy group of a bisphenol type epoxy resin. Resins with a secondary amine) are preferred.

As the crosslinking agent, it is preferable to use a blocked polyisocyanate sealed with a blocking agent such as alcohols, phenols, oximes and lactams.

The above-mentioned cationic electrodeposition paint contains a pigment such as a coloring pigment, an extender pigment, a rust preventive pigment, a hydrophilic and / or hydrophobic solvent, an additive and the like as required. The amount of the pigment can be 5 to 150 parts by weight based on 100 parts by weight of the resin solids.

The electrodeposition coating film usually has a thickness of 10 after baking.
The thickness is preferably set to be about 40 μm, more preferably 15 to 25 μm. It is more preferable to perform a normal chemical conversion treatment before the electrodeposition coating.

The intermediate coating composition for forming an undercoat layer in the method for forming a composite coating film of the present invention hides underlying defects,
This is for ensuring surface smoothness and imparting chipping resistance after top coating, and is applied using an intermediate coating containing various organic and inorganic coloring pigments and extender pigments.

Examples of the color pigments for the intermediate coating include organic azo chelate pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, dioxane pigments, and quinacridone. Pigments, isoindolinone pigments, metal complex pigments, etc., inorganic yellow salts, yellow iron oxide, red iron oxide, carbon black, titanium dioxide, etc., and extender pigments such as calcium carbonate, barium sulfate, clay, talc, etc. Is used. As a standard, gray intermediate coatings with carbon black and titanium dioxide as main pigments are often used, but it is also possible to use so-called color intermediate coatings that combine various coloring pigments according to the concealment of the top coat. it can.

The thermosetting film-forming resin of the intermediate coating is not particularly limited, and a film-forming resin such as an acrylic resin, a polyester resin, an alkyd resin, an epoxy resin, or a urethane resin can be used. These are used in combination with a curing agent such as an amino resin and / or a blocked isocyanate resin. 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.

The solid content in the intermediate coating is 30 to 7
0% by weight, preferably 35 to 55% by weight.
At the time of application, it is 10 to 60% by weight, preferably 20
５０50% by weight. The intermediate coating is preferably applied on a heat-cured or uncured electrodeposition coating film by a method such as electrostatic coating, air spray, or airless spray. , Generally 10-60
It is preferably about μm, more preferably about 20 to 50 μm. If the upper limit is exceeded, problems such as wrinkles and sagging may occur during coating. If the lower limit is not reached, the base cannot be concealed.

The intermediate coating film itself can be cured by heating at a temperature of about 100 to 180 ° C. In the present invention, the composite coating film is formed by combining the glitter pigment-containing coating film and the clear coating film to form a composite coating film. Excellent appearance and coating film performance can be exhibited.

It is preferable to form a color base coating film on the intermediate coating film according to the saturation of the top coating color. By forming a cured or uncured color base coating film as the first layer of the top coat, forming the second layer with the bright pigment-containing coating composition of the present invention, and further forming a clear coating film on a wet-on-wet basis, 3 with excellent design
A composite coating film of two coats of bake or three coats of one bake can be formed.

Examples of the color pigment of the color base paint used in the method for forming a composite coating film of the present invention include organic azo chelate pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, perinone pigments,
Perylene pigments, dioxane pigments, quinacridone pigments, isoindolinone pigments, metal complex pigments, etc., inorganic yellow salts, yellow iron oxide, red iron oxide, carbon black,
Calcium carbonate, barium sulfate, clay, talc, and the like are used as the extender, such as titanium dioxide.

The thermosetting film-forming resin of the color base paint is not particularly limited, and a film-forming resin such as an acrylic resin, a polyester resin, an alkyd resin, an epoxy resin, or a urethane resin can be used. These are used in combination with a curing agent such as an amino resin and / or a blocked isocyanate resin. From the viewpoint of pigment dispersibility or workability, a combination of an acrylic resin and / or a polyester resin with an amino resin is preferred.

When a composite coating film is formed by a three-coat, one-bake coating method, the bright pigment-containing coating film of the present invention and the color base coating film are applied on a wet-on-wet basis. It is preferable to control the viscosity of the coating film.

The addition amount of the viscosity control agent to the color base paint used for controlling the viscosity of the color base coating film is as follows.
0.1 to 100 parts by weight of resin solid content of the coating composition
20 parts by weight, preferably 0.2 to 15 parts by weight, more preferably 0.3 to 10 parts by weight. When the amount of the crosslinkable resin particles is more than 20 parts by weight, the appearance is deteriorated. When the amount is less than 0.1 parts by weight, the effect of controlling the viscosity is not obtained, which causes a break-in or inversion between layers.

The solid content in the color base paint is 1
It is 5 to 60% by weight, preferably 20 to 55% by weight. The solid content at the time of coating is 10 to 50% by weight, preferably 20 to 45% by weight. Color base paint is applied on the middle coat or electrodeposition coat by electrostatic coating,
It is preferable to apply by a method such as air spraying, and the dry film thickness of the formed coating film is generally preferably about 10 to 60 μm, more preferably about 20 to 50 μm. If the upper limit is exceeded, problems such as wrinkles and sagging may occur during coating. If the lower limit is not reached, the base cannot be concealed.

The color base coating film itself is about 100 to 1
It can be cured by heating at a temperature of 80 ° C. When heat-cured alone, the glitter pigment-containing coating composition of the present invention is applied thereon, and a clear coating is further applied thereon by wet-on-wet to form a 3-coat 2-bake composite. A coating can be formed. In addition, a color base coating film, a bright pigment-containing coating film and a clear coating film are combined on a wet-on-wet basis, and a composite coating film is formed and then heat-cured to form a three-coat one-bake composite coating film. And further excellent design properties can be exhibited.

As the form of the intermediate coating and the color base coating used in the present invention, a solution type is preferably used. If the solution type is used, an organic solvent type and an aqueous type (water soluble,
(Aqueous dispersibility, emulsion) and non-aqueous dispersion type. If necessary, a curing catalyst, a surface preparation agent and the like can be used.

The clear paint used in the method for forming a composite coating film of the present invention is formed to ensure surface smoothness and to provide other properties required for the coating film, and impairs the transparency of the coating film. To a lesser extent, a coloring pigment may be included.

The thermosetting film-forming resin of the clear paint is not particularly limited.
A film-forming resin such as a polyester resin, an epoxy resin, or 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. In terms of transparency or acid etching resistance, etc., a combination of an acrylic resin and / or a polyester resin and an amino resin,
An acrylic resin and / or a polyester resin having an epoxy curing system may be used.

The solid content in the clear paint 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, preferably 20 to 50% by weight. The clear coating, on the uncured bright pigment-containing coating film, electrostatic coating,
It is preferable to apply by a method such as air spraying, and the dry film thickness of the formed coating film is generally preferably about 10 to 60 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.

The clear coating film itself can be cured by heating at a temperature of about 100 to 180 ° C. In the present invention, the clear coating film and the glitter pigment-containing coating film, or the color base coating film and the glitter pigment-containing coating film are used. By forming a composite coating film by combining with the film and curing by heating, excellent appearance and coating film performance can be exhibited.

It should be noted that the clear coating preferably contains a viscosity controlling agent in order to apply the bright pigment-containing coating composition of the present invention wet-on-wet. The amount of the viscosity control agent to be added to the clear coating composition is 0.01 to 10 parts by weight, preferably 0.02 to 8 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the resin solid content of the coating composition. 03
It is added in an amount of up to 6 parts by weight. When the amount of the viscosity control agent is 10
If the amount is more than 0.1 parts by weight, the appearance deteriorates. If the amount is less than 0.1 part by weight, the effect of controlling the viscosity cannot be obtained, which may cause infiltration or inversion between layers.

As the coating form of the clear coating used in the present invention, a solution type is preferably used. If the solution type is a solution type, an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), a non-aqueous type can be used. Any of them. If necessary, a curing catalyst, a surface preparation agent and the like can be used.

In many cases, the composite coating film containing the glitter pigment-containing coating film as at least one layer is 30 to 3 times.
00 μm. Preferably it is 50 to 250 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.

[0062]

The present invention will be described below in detail with reference to examples. Parts mean parts by weight unless otherwise specified.

Preparation Example Preparation of Crosslinkable Resin Particles In a reaction vessel equipped with a stirring and heating device, a thermometer, a nitrogen inlet tube, a cooling tube and a decanter, 213 parts of bishydroxyethyl taurine, 208 parts of neopentyl glycol, 296 parts of phthalic anhydride were added. , 376 parts of azelaic acid and 30 parts of xylene were charged and heated. Water generated by the reaction was removed by azeotropic distillation with xylene. The temperature of the reaction solution was set to 210 ° C. over about 3 hours from the start of reflux, and stirring and dehydration were continued until the acid value equivalent to carboxylic acid reached 135 mgKOH / g (solid content).

After the temperature of the solution was cooled to 140 ° C., 500 parts of “Kajura E10 (trade name; glycidyl ester of versatic acid manufactured by Shell)” was dropped in 30 minutes, and then stirring was continued for about 2 hours. The reaction was completed. An amphoteric ionic group-containing polyester resin having an acid value of 55 mgKOH / g, a hydroxyl value of 91 mgKOH / g, and a number average molecular weight of 1250 was obtained.

The amphoteric ion-containing polyester resin 10
Parts, 140 parts of deionized water, dimethylethanolamine 1
, 50 parts of styrene and 50 parts of ethylene glycol dimethacrylate were vigorously stirred in a stainless steel beaker to prepare a monomer suspension. Also, an aqueous initiator solution was prepared by mixing 0.5 parts of azobiscyanovaleric acid, 40 parts of deionized water and 0.32 parts of dimethylethanolamine.

A reaction vessel equipped with a stirring and heating device, a thermometer, a nitrogen introducing tube and a cooling tube was charged with 5 parts of the amphoteric group-containing polyester resin, 280 parts of deionized water and 0.5 part of dimethylethanolamine. The temperature rose.
Here, 251 parts of the monomer suspension and 40.
82 parts were simultaneously added dropwise over 60 minutes, and the reaction was further continued for 60 minutes, and then the reaction was terminated.

A crosslinkable resin particle emulsion having a particle diameter of 55 nm as measured by a dynamic light scattering method was obtained. Xylene was added to this crosslinkable resin particle emulsion, water was removed by azeotropic distillation under reduced pressure, and the medium was replaced with xylene to obtain a xylene solution of crosslinkable resin particles having a solid content of 20% by weight.

Example 1 Preparation of a Bright Pigment-Containing Coating Composition A part of the thermosetting acrylic resin and the coloring pigment in the following formulation were mixed in advance with a tabletop disperser using glass beads as a dispersion medium. It was dispersed until it became 5 μm or less to prepare a pigment paste. In addition, the crosslinkable resin particles were gradually added during the stirring of the mixture of the resin and the solvent, and were uniformly dispersed in the solution. Thereafter, a pigment paste and the remaining components were sequentially added to prepare a glittering pigment-containing coating composition.

[0069] effect pigment-containing coating compositions formulated SDA-SILVER W-3 (Merck alumina flakes) 5.8 Degussa carbon FW-200 (manufactured by Degussa black pigment) 2.4 Cyanine Blue 5206 (Dainichi Seikasha 1.3 Thermosetting acrylic resin (Nippon Paint Co., Ltd. resin, hydroxyl value 45, 76.7 acid value 15, number average molecular weight 21000, solid content 55%) DIANAL HR2048 35.2 (Mitsubishi Rayon Co., Ltd.) Thermosetting acrylic resin, solid content 60%) Uban 20N60 45.3 (Butylized melamine resin, Mitsui Cytec, solid content 60%) Crosslinkable resin particles in the production example (Nippon Paint Co., solid content 20%) 4.5 Disparon KS273N (manufactured by Kusumoto Chemicals, Ltd., surface preparation agent) 0.2 n-butanol 4.0 xylene 10.7 torr Down 13.9 Total 200.0 resin solids / curing agent solid content ratio = 7/3 PWC = 9.5% crosslinked resin particle content (to resin solid content ratio) = 1.0%

Preparation Method of Composite Coating Film for Evaluation of Appearance Epoxy resin / block isocyanate curable cationic electrodeposition paint (Nippon Paint Co., Ltd., “Power Top U-50 (trade name) ") was electrodeposited such that the dry film thickness was about 20 μm, and baked at 160 ° C. for 30 minutes.
Next, a polyester / melamine-curable gray intermediate paint (Nippon Paint Co., Ltd., “Olga TO-H850 Gray (trade name)”) was applied on the obtained electrodeposition coating film to a dry film thickness of about 30.
The composition was spray-coated to a thickness of μm and baked at 140 ° C. for 20 minutes.

On the obtained intermediate coating film, the bright pigment-containing coating composition prepared in Example 1 was mixed with ethyl acetate / toluene / solvesso 100 / solvesso 150 = 20/50 /
Using a 20/10 dilution thinner, diluted with a No. 4 Ford cup at 20 ° C. for 13 seconds and adjusting the viscosity, an electrostatic coating machine (“A
uto REA (brand name) ", manufactured by Ransberg Gema Co., Ltd.)
Spray coating with 2 stage coating at an atomizing pressure of 4 kg / cm2, and the setting was left for 3 minutes.

Next, "Olga TO-563 Clear (trade name)" shown below was applied by wet-on-wet coating.
Paint A was diluted with a No. 4 Ford cup for 20 seconds using a diluted thinner of Solvesso 100 / xylene = 60/40 and applied so that the dry film thickness became about 30 μm, and the setting was carried out for about 7 minutes. After that, baking was performed at 140 ° C. for 20 minutes to prepare a coated plate for evaluation and used for evaluation.

Top coat clear paint A used for forming the composite coating film “Olga TO-563 Clear (trade name)” Nippon Paint Co., Ltd., acrylic / melamine-curable clear paint Resin solids / hardener solids Ratio = 65/35 PWC = 0%

Coating Appearance Evaluation Criteria A visual evaluation was performed indoors by 10 persons who could evaluate the finish of the coating film, and the results were comprehensively summarized according to the following criteria. ；: Excellent △; normal ×; inferior

Criteria for Design Evaluation Ten persons who can evaluate the finish of the paint film are visually evaluated in a room where sunlight shines on a part of the coated plate while the sunlight is applied, and the glitter (particles are shining) The results for the shining sensation and the feeling of depth (the sensation of light coming from inside the coating film) were comprehensively summarized according to the following criteria. 5; fairly good 4; excellent 3; normal feeling 2; slightly poor 1; fairly poor

Table 1 below shows the evaluation results of the above items.

Examples 2 to 5 Example 1 was repeated except that the addition amount of the crosslinkable resin particles and the addition amount of the alumina flake were changed as shown in Table 1 below.
According to the same procedure as described above, a glittering pigment-containing coating composition was produced, and a coated plate for appearance evaluation was prepared and evaluated. Table 1 shows the results.

Comparative Examples 1 to 4 The same procedure as in Example 1 was carried out except that the addition amount of the crosslinkable resin particles, the addition amount of the alumina flake, and the type of the brilliant pigment were changed as shown in Table 1. The pigment-containing coating composition was manufactured and a coated plate for evaluating appearance was prepared and evaluated. Table 1 shows the results.

[0079]

[Table 1]

Example 6 A method for forming a composite coating film by two coats and one bake Preparation of a coating composition containing a brilliant pigment In advance, a part of a thermosetting acrylic resin and a coloring pigment in the following composition were mixed with a glass bead. The particles were dispersed using a tabletop disper as a dispersion medium until the particle size became 5 μm or less, to prepare a pigment paste. In addition, the crosslinkable resin particles were gradually added during the stirring of the mixture of the resin and the solvent, and were uniformly dispersed in the solution. Thereafter, the pigment paste and the remaining components were sequentially added to prepare a glittering pigment-containing coating composition.

Formulation of glittering pigment-containing coating composition SDA-SILVER W-3 (alumina flake manufactured by Merck) 5.8 Degussa Carbon FW-200 (black pigment manufactured by Degussa) 2.4 Cyanine Blue 5206 (Dainichi Seika) 1.3 Thermosetting acrylic resin (Nippon Paint Co., Ltd. resin, hydroxyl value 45, 76.7 acid value 15, number average molecular weight 21000, solid content 55%) DIANAL HR2048 35.2 (Mitsubishi Rayon Thermosetting acrylic resin, solid content 60%) Uban 20N60 45.3 (butylated melamine resin, Mitsui Cytec, solid content 60%) Crosslinkable resin particles of the production example (Nippon Paint Co., solid content 20%) ) 9.1 Disparon KS273N (manufactured by Kusumoto Chemicals, Ltd., surface preparation agent) 0.2 n-butanol 4.0 xylene 6.1 torr Down 13.9 Total 200.0 resin solids / curing agent solid content ratio = 7/3 PWC = 9.5%

A method of forming a composite coating film A cationic electrodeposition paint (“Nippon Paint Co., Ltd.,“ Power Top U-50 (trade name) ”) was applied to a zinc phosphate-treated 0.8 mm thick, 10 cm × 30 cm dull steel plate. The dry film thickness is about 20
Electrodeposition coating was performed so as to have a thickness of μm, and baking was performed at 160 ° C. for 30 minutes. Next, a gray intermediate paint (“Olga TO-H850 Gray (trade name)” manufactured by Nippon Paint Co., Ltd.) is spray-coated on the obtained electrodeposition coating film so as to have a dry film thickness of about 30 μm, and is subjected to 140 ° C. For 20 minutes.

On the resulting intermediate coating film, the bright pigment-containing paint prepared in Example 6 was coated with ethyl acetate / toluene / solvesso 100 / solvesso 150 = 20/50/20 /
Using a dilution thinner of No. 10 and diluting the viscosity at 20 ° C. for 13 seconds using a No. 4 Ford cup and adjusting the viscosity, an electrostatic coating machine (“Auto”) was used to obtain a dry film thickness of about 18 μm.
REA (trade name), manufactured by Ransberg Gemma Co., Ltd.) Spray painting with 2 stage painting with atomization pressure of 4 kg / cm2
The setting was left for minutes.

Next, "Olga TO-563 Clear (trade name)" described above was applied by wet-on-wet coating.
Paint A was diluted with a No. 4 Ford cup for 20 seconds using a diluted thinner of Solvesso 100 / xylene = 60/40 and applied so that the dry film thickness became about 30 μm, and the setting was carried out for about 7 minutes. After that, baking was performed at 140 ° C. for 20 minutes to prepare a coated plate for evaluation and used for evaluation.

Top coat clear paint A used for forming the composite coating film “Olga TO-563 Clear (trade name)” Nippon Paint Co., Ltd., acrylic / melamine curable clear paint Resin solids / hardener solids Ratio = 65/35 PWC = 0%

[0086] Design evaluation evaluation criteria A visual evaluation was carried out by 10 persons who can evaluate the finish of the coating film in a room where sunlight shines and in a state where sunlight was applied to a part of the coated plate, and the shininess (particles were shining) Feeling of feeling) and feeling of depth (feeling of light coming from inside the coating film)
The results for each were comprehensively summarized according to the following criteria.
Table 2 shows the evaluation results. 5; fairly good 4; excellent 3; normal feeling 2; slightly poor 1; fairly poor

Examples 7 and 8 The same procedure as in Example 6 was repeated except that the type of alumina flake was changed as shown in Table 2 below to produce a brilliant pigment-containing coating composition and prepare a coated plate for appearance evaluation. make,
An evaluation was performed. Table 2 shows the results.

Comparative Examples 5 and 6 The same procedure as in Example 6 was carried out except that mica powder was used instead of alumina flakes as shown in Table 2, to produce a brilliant pigment-containing coating composition and to prepare a coated plate for appearance evaluation. And evaluated. Table 2 shows the results.

Example 9 Method of forming a composite coating film by three coats and two baking Preparation of a coating composition containing a brilliant pigment A desktop disperser in which a part of a thermosetting acrylic resin and a coloring pigment were previously used and glass beads were used as a dispersion medium. With a particle size of 5
It was dispersed until it became not more than μm and was prepared as a pigment paste. In addition, the crosslinkable resin particles were gradually added during the stirring of the mixture of the resin and the solvent, and were uniformly dispersed in the solution. Thereafter, the pigment paste and the remaining compounding components were sequentially added to prepare a bright pigment-containing coating composition.

Method of forming a composite coating film A cationic electrodeposition paint (Nippon Paint Co., Ltd., “Power Top U-50 (trade name)”) was applied to a zinc phosphate-treated 0.8 mm thick, 10 cm × 30 cm dull steel plate. The dry film thickness is about 20
Electrodeposition coating was performed so as to have a thickness of μm, and baking was performed at 160 ° C. for 30 minutes. Next, a white intermediate coating B (Nippon Paint Co., Ltd., “Olga TO-H860 White Intercoat (trade name))” was spray-coated on the obtained electrodeposition coating film so as to have a dry film thickness of about 30 μm. At 140.degree. C. for 20 minutes.

On the obtained white intermediate coating film, a color base paint C (“OLGA TO-646” manufactured by Nippon Paint Co., Ltd.) was applied.
White-collar base (brand name) ")
It was spray-coated to a thickness of μm, baked at 140 ° C. for 20 minutes after setting for about 7 minutes.

Next, the bright pigment-containing coating composition containing the coloring pigment prepared above was used together with ethyl acetate / toluene / solvesso 100 / solvesso 150 = 20/50/20 /
Using a No. 10 dilution thinner and a No. 4 Ford cup, diluted and viscosity adjusted at 20 ° C. for 13 seconds, an electrostatic coating machine (“Aut” was used to adjust the dry film thickness to about 18 μm.
o REA (trade name), manufactured by Ransberg Gema Co., Ltd.) at a spray pressure of 4 kg / cm2 and set for about 3 minutes.

Further, the above-mentioned "Olga TO-563 Clear (trade name)" was applied by wet-on-wet coating.
Paint A was diluted with a No. 4 Ford cup for 20 seconds using a diluted thinner of Solvesso 100 / xylene = 60/40 and applied so that the dry film thickness became about 30 μm, and the setting was carried out for about 7 minutes. After that, baking was performed at 140 ° C. for 20 minutes to prepare a coated plate for evaluation and used for evaluation. Table 2 shows the evaluation results.

Top coat clear paint A used for forming the composite coating film "Orga TO-563 Clear (trade name)" Nippon Paint Co., Ltd., acrylic / melamine-curable clear paint Resin solids / hardener solids Ratio = 65/35 PWC = 0%

White intermediate coating B "Olga TO-H860 White intermediate coating (trade name)" manufactured by Nippon Paint Co., Ltd., polyester / melamine curable coating Resin solid content / hardening agent solid content ratio = 70/30 PWC = 44%

Color base paint C "Olga TO-646 white color base paint (trade name)" Nippon Paint Co., Ltd. polyester / melamine curable paint resin solids / hardener solids ratio = 65/35 PWC = 45%

Comparative Example 7 A glittering pigment-containing coating composition was prepared and a coated plate for evaluation of appearance was prepared in the same procedure as in Example 9 except that mica powder was used instead of alumina flakes as shown in Table 2. An evaluation was performed. Table 2 shows the results.

Example 10 Method for forming a three-coat, one-bake composite coating film Preparation of glittering pigment-containing coating composition As shown in Table 2, Example 9 was repeated except that the amounts of the coloring pigment and the crosslinkable resin particles were changed. In the same manner as in the above, a bright pigment-containing coating composition was prepared.

Method of forming composite coating film A cationic electrodeposition paint (“Nippon Paint Co., Ltd.,“ Power Top U-50 (trade name) ”) was applied to a 0.8 mm thick, 10 cm × 30 cm dull steel plate treated with zinc phosphate. The dry film thickness is about 20
Electrodeposition coating was performed so as to have a thickness of μm, and baking was performed at 160 ° C. for 30 minutes. Then, a color intermediate coating D (Nippon Paint Co., Ltd., “Olga TO-H840 White Color Base (trade name))” was applied on the obtained electrodeposition coating film to a dry film thickness of about 30 μm.
Spray coating was performed so as to obtain a baked coating film at 140 ° C. for 20 minutes.

On the obtained color intermediate coating film, a color base paint E (Nippon Paint Co., Ltd., “Orga TO-H30
0 white base color (brand name) ") with ethyl acetate /
Toluene / solvesso 100 / solvesso 150 = 20
/ 50/20/10 diluted thinner, No. 4 Ford cup diluted and viscosity adjusted to 13 seconds at 20 ° C using a No. 4 Ford cup, electrostatic coating machine so that dry film thickness is about 8 to 10 µm ("AutoREA (trade name)", manufactured by Randsburgh Gemma Co., Ltd.) was spray-coated with one stage at an atomizing pressure of 4 kg / cm2, and the setting was left for about 3 minutes.

Next, the bright pigment-containing coating composition obtained by using the coloring pigment obtained above in combination with the previously obtained coloring pigment was diluted and adjusted for the viscosity in 13 seconds by wet-on-wet, and the dry film thickness was about 8 to 10 μm. So that the electrostatic coating machine (“Auto R
EA (trade name), manufactured by Landsberg Gema Co., Ltd.), and spray-coated at an atomizing pressure of 4 kg / cm2, and set again for about 3 minutes.

Further, the above-mentioned "Olga TO-563 Clear (trade name)" was applied by wet-on-wet coating.
Paint A was diluted with a No. 4 Ford cup for 20 seconds using a diluted thinner of Solvesso 100 / xylene = 60/40 and applied so that the dry film thickness became about 30 μm, and the setting was carried out for about 7 minutes. After that, baking was performed at 140 ° C. for 20 minutes to prepare a coated plate for evaluation and used for evaluation. Table 2 shows the evaluation results.

Top coat clear paint A used for forming the composite coating film "Olga TO-563 Clear (trade name)" Nippon Paint Co., Ltd. acrylic / melamine curable clear paint Resin solids / hardener solids Ratio = 65/35 PWC = 0%

Color intermediate paint D "OLGA TO-H840 White Color Base (trade name)" Nippon Paint Co., Ltd., polyester / melamine curable paint Resin solids / hardener solids ratio = 70/30 PWC = 45 %

Color base paint E "Olga TO-H300 White base color paint (trade name)" Nippon Paint Co., Ltd., acrylic / melamine curable paint Resin solids / hardener solids ratio = 65/35 PWC = 45 %

Comparative Example 8 A glittering pigment-containing coating composition was prepared and a coated plate for appearance evaluation was prepared in the same procedure as in Example 10 except that mica powder was used instead of alumina flakes as shown in Table 2. An evaluation was performed. Table 2 shows the results.

[0107]

[Table 2]

[0108]

According to the present invention, a layer formed by the glittering pigment-containing coating composition of the present invention is formed on a base material undercoated with an electrodeposition coating and an intermediate coating, and a layer formed by the clear coating composition is further formed thereon. By using the method for forming a composite coating film, a composite coating film having an unprecedented brilliant feeling and a novel design can be formed without lowering the finished appearance and the like.

In particular, although the degree of gloss (gloss intensity) of the glitter pigment changes depending on the viewing angle, the coating film containing the alumina flakes becomes more conspicuous than before. In addition, a slight change in gloss according to the degree of inclination of the coating film surface can be recognized, and the color tone changes variously according to the viewing angle. On the other hand, when the glossiness of the glittering pigment is slightly weak, the color of the non-brilliant pigment is superior on the coating film surface. Therefore, for example, the viewing angle is different between the lower part and the upper part of a large area, and the lower part has a strong gloss effect,
In the upper part, the luster effect is weak, and the color of the non-brilliant colored pigment may be superior. In this case, different color tones coexist at the same time on one coating film surface, and express an unprecedentedly high design effect.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09D 5/36 C09D 5/36 7/12 7/12 Z

Claims (6)

[Claims] 1. A glitter pigment-containing coating composition comprising a glitter pigment and alumina flakes and a viscosity controlling agent. 2. The bright pigment-containing coating composition according to claim 1, which contains crosslinked resin particles as a viscosity controlling agent. 3. A method for forming a composite coating film on an undercoated substrate by two coats and one bake, wherein the first layer is formed by the glitter pigment-containing coating composition according to claim 1 or 2. The method for forming a composite coating film. 4. A method for forming a composite coating film on an undercoated substrate by 3 coats 2 bake or 3 coats 1 bake, wherein the second layer is formed by the glitter pigment-containing coating composition according to claim 1 or 2. Forming a composite coating film. 5. A composite coating film formed by the method for forming a composite coating film according to claim 3. 6. An article having the composite coating according to claim 5.