JPH08134385A - Top-coating composition and method for forming composite coating film - Google Patents

Abstract

PURPOSE: To obtain a coating film having high weather resistance by using a clear color coating material containing a specific dye. CONSTITUTION: This top-coating composition contains (A) 100 pts.wt. of a vehicle in terms of solid and (B) 0.05-20 pts.wt. of an azo dye containing a metal complex salt, 0.2-10 pts.wt. of an organo-nickel-based quencher, 0.2-10 pts.wt. of an ultraviolet absorber and 0.1-5 pts.wt. of a hindered amine compound in terms of solid component based on 100 pts.wt. of the solid component of the vehicle. This invention also relates to a method for forming a composite coating film. The color range of the coating film can be expanded by the improvement in the weather resistance of the clear color coating film containing the dye.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a top coating composition and a composite coating forming method, and more particularly to a top coating composition having improved weather resistance and a composite coating forming method.

[0002]

2. Description of the Related Art In recent years, in the case of coating automobiles, for example, a top coat is coated on a base coat coated surface in which a metallic powder of a usual organic or inorganic pigment or powder of aluminum or the like is mixed.

Further, since the conventional top coat transmits most of the ultraviolet rays, the pigments (especially yellow and green organic pigments) in the base coat are deteriorated by the ultraviolet rays, and the discoloration and fading are significantly reduced.

Therefore, it has been desired to prevent deterioration such as discoloration or fading of the pigment in the base coat due to exposure to ultraviolet rays outdoors.

In Japanese Patent Publication No. 53-28335, "Metallic finishing method", there is proposed a transparent clear coat containing an ultraviolet absorber which does not decompose at a heat curing temperature, while containing no coloring pigment.

[0006] Further, in Japanese Patent Publication No. 60-40905, "Metallic finishing method", by adding an ultraviolet absorber to the base coat paint or both the base coat paint and the top coat paint, the top coat is exposed to ultraviolet rays outdoors. It is disclosed to prevent deterioration such as cracks in the base coat, discoloration and fading of the pigment in the base coat. Here, the top coat is a transparent clear coat containing no coloring pigment.

However, as in the above publication, it is difficult to obtain a coating film having a deep color tone, for example, in the case of metallic finish, only by coating one layer of a transparent clear coat containing no color pigment on the coated surface of the base coat. there were.

In view of the above, according to the method for forming a four-layer metallic coating film disclosed in JP-A-61-18469, in order to obtain a coating film with a deep color tone, which is difficult to obtain by metallic finishing, the base coat surface is coated. The clear clear paint is applied on top of it by wet-on-wet and then baked, then the color clear paint containing highly transparent pigment is used as the second layer, and the clear clear paint is wet-on-wet as a top coat and baked. There is disclosed a method for forming a four-coat two-bake metallic coating film having four layers. Note that this publication also describes that each clear coating may contain an ultraviolet absorber, a light stabilizer, or the like in order to improve weather resistance.

Further, in recent years, a coating film having high designability has been demanded, and it is desired to obtain a composite color coating film having a clear color. For example, in the case of producing a purple color in automobile painting, conventionally, an enamel paint prepared by previously mixing red and blue color pigments was prepared and applied. However, such a method generally has a drawback in that the vividness of colors is impaired because subtractive color mixing is generally performed.

Therefore, in Japanese Patent Application Laid-Open No. 3-157167, "Clear Composite Color Coating Finishing Method", a color base is coated as a base, and after baking treatment, a white / black hiding film thickness of 100 μm or more is applied. -It is proposed to paint clear and bake. As a result, the colorant contained in the color base and the colorant contained in the color clear are not mixed with each other, and the base color of the color base and the color of the upper layer of the color clear are combined in a human retina shape and recognized as a composite color. Therefore, a composite color coating film having clear colors can be obtained without causing clouding of the color due to the conventional subtractive color mixing. In addition,
In the examples, the colorant contained in the color clear is a dye.

[0011]

However, the above-mentioned JP-A-61-18469 and JP-A-3-15716.
In the composite coating film disclosed in Japanese Patent Publication No. 7, even if the color clear contains an ultraviolet absorber and a light stabilizer, when the color clear coat after coating does not contain the ultraviolet absorber and the like uniformly. However, there is a possibility that a part of ultraviolet rays may pass therethrough to cause discoloration or fading of the pigment of the base coat, and that the pigment or dye contained in the color clear paint may be directly exposed to ultraviolet rays to cause discoloration or fading.

The present invention has been made in view of the above problems, and an object thereof is to obtain a composite coating film having a clear color and a deep color tone, and further having high weather resistance. Another object of the present invention is to provide a top coating composition and a method for forming a composite coating film.

[0013]

The present invention is directed to (A) 100 parts by weight of a vehicle in terms of solid content and (B) 100 parts by weight of the vehicle in terms of solid content in terms of the solid content of a metal-containing complex azo salt. 0.05 to 20 parts by weight of an organic dye, 0.2 to 10 parts by weight of an organic nickel quencher, and an ultraviolet absorber of 0.
2 to 10 parts by weight and 0.1 to 0.1% of hindered amine compound
And a coating composition containing 5 parts by weight.

Further, the above-mentioned top coating composition is used as a color clear coat, and at least one layer of the color clear coat is formed on a base coat containing (A) a coloring pigment, or a bright pigment, or a bright pigment and a coloring pigment. Or (B) at least one layer of the above-mentioned color clear coat is formed on the transparent clear coat which is further formed by coating on the above-mentioned base coat, and at least one layer of the transparent clear coat is further formed on the above-mentioned color clear coat, if necessary. A method for forming a composite coating film is provided.

Topcoat Paint Composition (Color Clear Paint) First, as the vehicle, various thermosetting resins or thermoplastic resins are used. Examples of the thermosetting resin that serves as a vehicle include acrylic resin, polyester resin, alkyd resin, and epoxy resin. These resins are used together with a crosslinking agent such as an amino resin or a blocked polyisocyanate compound, if necessary. As the cross-linking agent, alkoxy groups such as n-butylated melamine resin and tributylated melamine resin are methoxy group, ethoxy group, n
Examples thereof include an alkylmethylmelamine resin having a -butoxy group and an i-butoxy group, and a benzoguanamine resin.
These resins are usually obtained by subjecting an amino compound such as melamine and benzoguanamine to an addition reaction or an addition condensation reaction of formaldehyde and paraformaldehyde,
It is produced by reacting a monohydric alcohol having 1 to 4 carbon atoms for etherification. Further, as the blocking agent for the blocked polyisocyanate compound, phenol, p
-Nitrophenol, m-cresol, acetylacetone, ethyl acetone acetate, ε-caprolactam and the like are used.

When a cross-linking agent is used, the acrylic resin or polyester resin and the melamine resin as the cross-linking agent are mixed in a weight ratio of 9: 1 to 5: 5, preferably 8.
It is set to 5:15 to 6: 4. If the blending amount of the melamine resin exceeds the above ratio, the coating film strength will be insufficient, and if it falls below the above ratio, the coating film will crack. When the polyisocyanate compound is used as the crosslinking agent, it is desirable to set the molar ratio of the polyisocyanate group to the hydroxyl group in the thermosetting resin component to be 0.3: 1 to 1.5: 1. If the compounding amount of the isocyanate compound is less than the above molar ratio, curing will be poor, and if it exceeds this ratio, the water resistance will decrease.

Epoxy resins 3 to 10 are used within a range in which compatibility with 100 parts by weight of the above resin (as solid content) is allowed.
When used in combination with parts by weight, the adhesion is improved and a preferable coating film can be produced. When using a non-blocked polyisocyanate compound to prepare a room temperature curable coating,
The curing agent components are individually blended to form a two-component paint. At that time, the amount of the isocyanate and the catalyst, the addition amount, the copolymer concentration, the content of the unit based on the hydroxyalkyl vinyl ether of the copolymer, and the like are adjusted to be 1 to 1
It is possible to obtain a coating composition having a pot life of about 0 hours and curing at room temperature for several hours to several days to form a good coating film.

On the other hand, examples of the thermoplastic resin used as the vehicle include chlorinated olefin resins such as chlorinated polyethylene and chlorinated polypropylene which are commonly used in the paint field,
Vinyl chloride resin, vinyl acetate, vinylidene chloride, and vinyl resins obtained by copolymerizing these, and further cellulosic resins,
An acetal resin, an alkyd resin, a chlorinated rubber resin, or the like can be used, and a coating composition with high designability can be obtained even by using these thermoplastic resins. In addition,
Vehicle is organic solvent type and water-based (water-soluble, water-dispersible)
Can be used as paint.

The metal-containing complex salt azo dye has a specific structure among the azo dyes and forms a metal complex salt during the production of the dye. As the metal-containing complex salt azo dye, a 1: 1 type acidic metal-containing complex salt dye, which requires a strong acid bath at the time of dyeing and structurally has a 1: 1 molecule ratio of metal to dye, and neutral or weak dyeing at the time of dyeing. There are 1: 2 type acidic metal-containing complex salt dyes in which the ratio of the metal to the dye is 1: 2 molecule because of the good structure of the acid bath. Specifically, "Acid Yellow" (existing chemical substances (public notice number of the Official Gazette) 595-1411), "Acid Orange"
(Ibid, 745-1470), "Acid Orange" (Ibid,
122 5-1484), "Acid Red" (ibid., 180)
5-4308), "Acid Blue" (same 234 5-1)
714), "Acid Brown" (ibid., 44 5-178).
2), "Acid Brown" (Id. 296 5-4419),
"Acid Black" (the same, 52 5-1887), "Acid B
lack ”(Ibid 1585-1909),“ Solvent Yell
ow ”(ibid., 825-3056),“ Solvent Orange ”
(Ibid, 54 5-3073), "Solvent Red" (Ibid,
122 5-3096), "Solvent Red" (ibid., 13
25-3097), "Solvent Blue" (the same, 70 5-
3127), "Solvent Black" (the same, 27 5-31
46), "Solvent Black" (Id., 29 5-314)
7), "Solvent Black" (Ibid, 34 5-3148)
And at least one of the above.

As the organic nickel quencher, [2.
2'-thiobis (4-tertiary octylphenolate)]-
2-ethylhexylamine-nickel (II), nickel dibutyl-dithiocarbamate, [2.2'-thiobis (4-tertiary octylphenolate)]-n-butylamine-nickel (II), nickel bis (octylphenyl) ) Sulfide, nickel complex 3,5-di-tert-butyl-4-hydroxybenzylic amid monoethylate, 2.2′-thiobis (4-tertiary octylphenolate)] triethanolamine-nickel (I
At least one kind such as I) is preferable. More preferred is [2.2′-thiobis (4-tertiary octylphenolate)]-2-ethylhexylamine-nickel (II). The quencher is a substance that hardly absorbs ultraviolet rays but efficiently traps active free radicals generated in the polymer material by the ultraviolet rays.

As the ultraviolet absorber, benzophenone,
2,4-dihydroxybenzophenone, 2,2 ', 4
4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 '
-Dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 5-chloro-
Benzophenone compounds such as 2-hydroxybenzophenone, 2- (2'-hydroxy-5'-methyl-phenyl) benzotriazole, 2- (2'-hydroxy-).
3 '-, 5'-ditert-butyl-phenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methyl-phenyl) benzotriazole, 2- (2'-hydroxy -3 '-, 5'
-Ditertiary-butyl-phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-,
5'-ditertiary-isoamyl, phenyl) benzotriazole, 2- (hydroxy-5-tertiary-
Butyl-phenyl) benzotriazole and other benzotriazoles, phenyl salicylate, 4-tachary-butyl-phenyl salicylate, p-octyl-phenyl salicylate and other salicylates, and ethyl-2-
Acrylic derivatives such as cyano-3,3'-diphenyl acrylate and 2-ethylhexyl-2-cyano-3,3'-diphenyl-acrylate, and N- (2-ethoxyphenyl) -N '-(4-isododecylphenyl ) -Ethanediamine, N- (p-ethoxycarbonylphenyl)
-N'-ethyl-N'-phenylformamidine, 1,
6-hexamethylenebis (N, N dimethylsemicarbazide), 1,1,1 ', 1'-tetramethyl-4,4'
(Methylene-di-p-phenylene) disemicarbazide,
Is at least one kind.

The hindered amine compound is used as a light stabilizer and is at least one of (I) shown in the following chemical formula 1 and (II) shown in the chemical formula 2 below.

[0023]

Embedded image

Embedded image Further, in the top coating composition, the content of the metal-containing complex salt azo dye is 0.05 to 20 parts by weight in terms of solid content based on 100 parts by weight in terms of solid content of the vehicle, and the solid content is It is preferably 0.1 to 10 parts by weight in terms of conversion, and more preferably 1 to 5 parts by weight in terms of solid content. When the content of the metal-containing complex salt azo dye is less than 0.05 parts by weight, the colorability is poor and a good color clear coating film cannot be obtained. On the other hand, when the content of the metal-containing complex salt azo dye exceeds 20 parts by weight, there is too much difference in brightness from the base coat, and color unevenness and darkening occur at the edges, resulting in a good color clear coating film. Absent.

Further, in the top coating composition, the content of the organic nickel quencher is 0.2 to 10 parts by weight in terms of solid content with respect to 100 parts by weight in terms of solid content of the vehicle. Is preferred, and 0.5 to 0.5 in terms of solid content.
It is more preferably 2 parts by weight. When the content of the organic nickel-based quencher is less than 0.2 parts by weight, the quenching effect is insufficient and the weather resistance becomes poor. For example, the pigment in the base coat undergoes discoloration, fading, etc. upon exposure to ultraviolet light.
On the other hand, when the content of the organic nickel quencher exceeds 10 parts by weight, the water resistance becomes poor and there is no cost merit.

In the top coating composition, the content of the ultraviolet absorber is 100 in terms of the solid content of the above-mentioned vehicle.
It is preferably 0.2 to 10 parts by weight in terms of solid content, and more preferably 0.5 to 2 parts by weight in terms of solid content, relative to parts by weight. When the content of the ultraviolet absorber is less than 0.2 parts by weight, the ultraviolet absorbing effect is insufficient and the weather resistance becomes poor. That is, the pigment in the base coat undergoes discoloration, fading, etc. upon exposure to ultraviolet light. On the other hand, when the content of the ultraviolet absorber exceeds 10 parts by weight, the water resistance becomes poor and there is no cost advantage.

Further, in the top coating composition, the content of the hindered amine compound is preferably 0.1 to 5 parts by weight in terms of solid content, relative to 100 parts by weight in terms of solid content of the above vehicle, Furthermore, it is 0.2 to in terms of solid content.
It is more preferably 1 part by weight. When the content of the hindered amine compound is less than 0.1 part by weight, the light stabilizing effect is insufficient and the weather resistance becomes poor. That is, the pigment in the base coat undergoes discoloration, fading, etc. upon exposure to ultraviolet light. On the other hand, when the content of the hindered amine compound exceeds 5 parts by weight, water resistance becomes poor and there is no cost advantage.

In addition to these components, the top coating composition of the present invention may optionally contain the following solvents and additives within a range that does not impair the effects of the present invention.

Examples of the solvent include various aromatic hydrocarbons such as toluene and xyleneno, aliphatic hydrocarbons such as n-hexane and heptane, and various aromatic hydrocarbons mainly consisting of aliphatic hydrocarbons and containing some aromatic hydrocarbons. Petroleum fraction having, butyl acetate, ethylene glycol diacetate, 2
Esters such as ethoxyethylene acetate, ketones such as acetate and methyl isobutyl ketone, alcohols such as butyl alcohol, and water have been used. However, when a polyisocyanate compound is used as the crosslinking agent, a solvent having an active hydrogen group that reacts with the polyisocyanate compound cannot be used. These solvents are used in an amount of 5 parts by weight based on 100 parts by weight of the solid content of the vehicle resin component.
50 parts by weight of the solvent blended in the range of 0 to 200 parts by weight.
If the amount is less than 100 parts by weight, it becomes difficult to produce the coating composition, and if the amount exceeds 200 parts by weight, the viscosity becomes too low, resulting in sagging during coating film formation.

As the additive, various additives commonly used in conventional coating compositions can be arbitrarily mixed. For example, a curing catalyst such as dodecylbenzene sulfonic acid, a benzophenol-based antioxidant, a surface conditioner such as silicone or an organic polymer, an anti-sagging agent, and a thickener are appropriately used. These components are usually used in the coating film forming resin 10
The amount of 0.1 to 5 parts by weight relative to 0 parts by weight (solid content) can improve the performance of paints and coating films, but if the amount is too large, cissing occurs during film formation. Enough
It is not preferable because it causes deterioration of interlayer adhesion.

Even when the composition obtained by removing the metal-containing complex salt azo dye from the top coating composition of the present invention is used as a transparent clear coating, the weather resistance of the composite coating film formed in the same manner as the above-mentioned top coating composition is improved. Be improved.

Production Method The production method of the top coating composition of the present invention is not particularly limited,
Any method known to one of ordinary skill in the art can be used. For example, a desired topcoat coating composition can be obtained by dissolving a compound such as a dye using a dissolver or the like according to a conventional method. The solid content of the top coating composition according to the present invention is 30 to 70 parts by weight at the time of production and 10 to 50 at the time of coating.
It is preferably in the range of parts by weight.

The top coating composition is diluted with a solvent so as to have an appropriate viscosity, and then applied by a method such as spraying or coating. The viscosity of the top coating composition is measured by Four Cup # 4. The viscosity of the composition such as spray coating is adjusted to 10 to 30 seconds / 20 ° C. with Four Cup # 4.

As the coating machine, an atomizing type coating machine is preferably used, and examples thereof include an air sprayer, an airless sprayer, and various electrostatic coating machines.

The composite coating film forming method of the composite coating film forming method of the present invention is as follows.

First, a coloring pigment, or directly on the base coat, or on the undercoat coat, or on the intermediate coat coat overlaid on the base coat, or
A base coat containing a bright pigment or a bright pigment and a coloring pigment is applied. In the case of a metallic base (brightening pigment or a coating containing a brightening pigment and a coloring pigment), the coating is preferably a solution type from the viewpoint of the metallic feel of the resulting coating film. In addition to normal solution type, high solid, non-aqueous dispersion type, water-soluble,
Any metallic base paint such as emulsion, slurry, etc. can be used. In order to prevent the base coat and the top coat from being mixed with each other, it is preferable to select the resin for the base coat by paying particular attention to the following points (a) to (c). Especially wet topcoat over basecoat
Care should be taken when painting on-wet. That is, when the base coat and the top coat are mixed with each other, the orientation of the pigment particles in the base coat, particularly the glitter metallic pigment particles, becomes poor, and the gloss is lowered to deteriorate the finish. Here, the top coat means a color clear coat or a combination of a color clear coat and a transparent clear coat.

Further, in the case where the metallic base paint is of a solution type and solid color or mica color is used, when the resin for the base coat is selected by paying attention to the following points (a) to (c), the gloss is deteriorated. effective.

That is, (a) the molecular weight of the base coat resin is made larger than that of the top coat resin. When an acrylic resin is used as the resin in the top coat paint, the weight average molecular weight of the acrylic resin is 8000 to 200.
Since it is about 00, the weight average molecular weight of the base coat resin is preferably about 30,000 to 50,000.

(B) Different resins are used for the base coat and the top coat. When an acrylic resin is used as the top coat resin, for example, polyester or cellulose acetate butyrate is used together as the base coat resin.

(C) The solubility parameter (δsp) of the base coat resin is made larger than the solubility parameter of the top coat resin. Since the solubility parameter of the resin for topcoat is generally about 9.8 to 11.2, the solubility parameter of the resin for basecoat is set to 10.5 in order to prevent dissolution by the organic solvent in the topcoat paint.
It is preferably about 11.5. If the solubility parameter of the base coat resin is less than 10.5, mixing with the top coat paint occurs and the finished appearance of the coating film deteriorates. Also, the solubility parameter of the base coat resin is 1
If it exceeds 1.5, the water resistance of the coating film deteriorates and the weather resistance is impaired.

By selecting the resin for the base coat while paying attention to the above points, the miscibility between the base coat and the top coat is reduced, and it is possible to prevent deterioration of gloss and metallic unevenness.

The top coat is composed of 2 coats and 1 bake (2c-
1b) method, 3 coat 1 bake (3c-1b) method, 4
Coat 3 bake (4c-3b) method is standard, but 2
Coat 2 bake (2c-2b) method, 3 coat 2 bake (3c-2b) method, 3 coat 3 bake (3c-3b)
Method, 4 coat 1 bake (4c-1b) method, 4 coat 2 bake (4c-2b) method, 4 coat 4 bake (4c)
-4b) method may be used.

The base material to be applied includes metals such as iron, aluminum, copper or alloys thereof, inorganic materials such as glass, cement and concrete,
Polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyamide, polyacryl, polyester,
The plastic materials such as ethylene-polyvinyl alcohol copolymer, vinyl chloride resin, vinylidene chloride resin, polycarbonate, polourethane and various FRPs, wood and fiber materials are applicable. It is optional to apply an appropriate undercoat or press coat material to these base materials in advance.

The coating film can be formed directly on the above-mentioned base material or undercoat, but when it is used as an overcoating material for an automobile body, the following step is applied to a material which has been subjected to a surface treatment such as chemical conversion treatment. After applying the undercoat and the intermediate coat according to the above, apply the top coat.

First, as an undercoat paint, an electrodeposition paint is electrodeposited and baked. As the electrodeposition coating, either a cation type electrodeposition coating or an anion type electrodeposition coating can be used, but a cation type electrodeposition coating is preferable from the viewpoint of durability. Electrodeposition coating by a general method, alkyd resin-based or polyester resin as a coating film of a cationic electrodeposition coating obtained by baking, acrylic resin-based coating by a general method, for example, electrostatic spray coating, By baking according to the method, an intermediate coating film having a dry film thickness of 20 to 60 μm is formed. 1 to 3 on the intermediate coating film, on the color pigment, or on the bright pigment, or on the base coat containing the bright pigment and the color pigment.
Apply a paint type color clear as a top coat with the combination shown in. At this time, a dry film thickness of the base coat is 10 to 40 μm, and a dry film thickness of each top coat is 20 to 60 μm.

Further, the composite coating film forming method of the present invention can be modified in the following three coating systems.

(1) First, as shown in FIG. 1, the above-mentioned top coating composition was used as a color clear coat, and a coloring pigment,
Alternatively, it is a method for forming a composite coating film in which at least one layer of the color clear coat is formed on a base coat containing a bright pigment or a bright pigment and a coloring pigment.

In FIG. 1, the solid line indicates baking.
And the dashed-dotted line indicates wet-on-wet. However, the coating conditions are not limited to these, and baking and wet-on-wet may be appropriately performed. In addition, color clear A, color clear B and color clear C
The dyes contained in each are different. Further, “M” means a metallic base coat, and means an overcoat containing a bright pigment or a topcoat containing a bright pigment and a coloring pigment. On the other hand, "S" means a solid base coat and means a color pigment-containing top coat.

(2) As shown in FIG. 2, it is a method for forming a composite coating film in which at least one transparent clear coat is further formed on the color clear coat as in the above (1). Here, the transparent clear contains a vehicle, a solvent, and an additive. Note that FIG. 2 is described according to FIG.

(3) As shown in FIG. 3, a transparent clear coat formed by further coating is formed on a base coat containing a coloring pigment, a bright pigment, or a bright pigment and a coloring pigment. A method for forming a composite coating film in which at least one layer of color clear coat is formed by coating the above-mentioned overcoating coating composition on a transparent clear coat, and at least one layer of transparent clear coat is further formed on the above color clear coat, if necessary. Is. Note that FIG. 3 corresponds to FIG.
It was described in accordance with.

Here, the base coat is formed of a base paint, and the base paint contains a vehicle, a pigment, a solvent, and an additive. The vehicle, the solvent and the additives are the same as those explained in the above-mentioned top coating composition,
The description is omitted. The amount of the solvent blended is 10 to 100 parts by weight in terms of the solid content of the vehicle resin component.
When the amount of the solvent material blended in the range of 1000 parts by weight, preferably 50 to 500 parts by weight, is less than 10 parts by weight, it becomes difficult to produce a coating material, and when it exceeds 1000 parts by weight, the viscosity becomes too low and a coating film is formed. Sagging occurs. Further, the amount of the additive is usually 5 parts by weight or less with respect to 100 parts by weight of the coating film-forming resin (solid content), but the performance of the paint and the coating film can be improved. If the amount is too large, cissing is sufficient at the time of forming the coating film, which causes deterioration of interlayer adhesion, which is not preferable.

As the pigment contained in the base paint, various organic and inorganic color pigments and luster pigments that are commonly used for paints can be used. Examples of the color pigments include organic azo lake pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, verinone pigments, berylylene pigments, phthalone pigments, dioxazine pigments, quinacridone pigments. Inorganic yellow lead, yellow iron oxide, red iron oxide, carbon black, titanium dioxide, etc., such as isoindolinone pigments and metal complex pigments are used.

Examples of the bright pigments include aluminum foil, bronze foil, tin foil, gold foil, silver foil, copper foil, metallic titanium foil, stainless steel foil, nickel foil, chrome foil, cobalt sulfide, manganese sulfide and titanium sulfide. Alloy foils such as, metal-based foils coated with plastic, foil-shaped phthalocyanine blue, and mica particles coated with metal oxides such as titanium oxide and iron oxide.

In the present invention, the pigment is generally a white, black, or colored inorganic compound and an organic compound which are insoluble in water or a medium such as oil or solvent, and is composed of a powder in a fine particle state. In the state, it does not have the ability to dye an object. However, it refers to a substance that adheres to an object with the aid of a vehicle (a color-developing agent) or is dispersed in an object and colored. On the other hand, a dye is generally a colored organic compound that dissolves in water, a medium such as oil or solvent, and has the ability to dye and color objects by themselves in the state of solution or dispersion. Say.

[0054]

According to the present invention, in the topcoat coating composition, the non-covalent (isolated) electron pair present in the nitrogen atom or oxygen atom in the ultraviolet absorber or the hindered amine compound is contained in the metal-containing complex azo dye. It is presumed that it is coordinated with nickel contained in the organic nickel-based quencher and forms an atomic group, that is, a coordination compound or a metal complex. Since this coordination compound has a unique structure, it is considered that when the top coating composition of the present invention is applied on the base coat, the coordination compound is present in a constant sequence in the coating film.

Therefore, when the top coating composition of the present invention is applied as a top coat, the metal-containing complex salt azo dye is uniformly dissolved in the coating film, and the transparency of the top coat is maintained.
A composite coating film having a clear color and a deep color tone is obtained. In addition, an ultraviolet absorber in the coating film of the top coat,
Since the organic nickel-based quencher and the hindered amine compound, which is a light stabilizer, are uniformly dispersed, there is no risk of ultraviolet rays penetrating the top coat and discoloring or fading the pigment of the base coat, and the metal-containing metal in the top coat. The complex salt azo dye can be exposed to ultraviolet rays to form a composite coating film with little risk of discoloration or fading.

[0056]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to these examples.

Examples 1 to 15 and Comparative Examples 1 to 14 (1) Pretreatment: length 90 mm, width 200 mm, thickness 0.8
mm steel plate was subjected to chemical conversion treatment using a zinc phosphate-based metal surface treatment material (“Surfdyne SD2500”, manufactured by Nippon Paint Co., Ltd.) as the coating target city.

(2) Undercoat: Cationic electrodeposition paint ("Power Top U-600", manufactured by Nippon Paint Co., Ltd.) was used for electrodeposition coating to form an undercoat film having a dry film thickness of about 20 μm.

(3) Intermediate coating: Polyester / melamine resin-based baking coating ("Olga P-5", Nippon Paint Co., Ltd.)
Made by spray coating under the following conditions,
Bake cure at 140 ° C / 20 minutes to dry film thickness 35
An intermediate coating film of -40 μm was formed.

Spray gun: REA (manufactured by Randsburg Gemma) Coating viscosity: 25 seconds / # 4 Ford cup / 20 ° C. (4) Topcoat: Acrylic / melamine resin-based paint containing aluminum foil ("Superlac M-120""Silver" manufactured by Nippon Paint Co., Ltd. was used for electrostatic coating by the air atomization method. A metallic topcoat film having a dry film thickness of about 15 to 20 μm was formed. Coating viscosity: 1
2.5 seconds / # 4 Ford Cup Paint stage: 1st → 1 minute flash off → 2nd (5) Color clear coating and clear coating: wet on top of top coating film Table 1, Table 2 by wet method
The color clear paint shown in Table 3 was applied and then baked to obtain a test plate on which a composite paint film having a dry film thickness of the color clear paint film of 35 to 40 μm was formed (coating system A).
For coating system B, a thermosetting acrylic clear melamine resin clear clear coating (“Superlac O-130 clear”, Nippon Paint Co., Ltd.) on the color clear coating film of coating system A.
Manufactured) and baked to obtain a test plate on which a composite coating film having a dry film thickness of the transparent clear coating film of 35 to 40 μm was formed. In the coating system C, a test plate having a composite coating film in which the coating order of the color clear coating and the transparent clear coating in the coating system B was reversed was obtained.

(6) Evaluation of coating film: For each test plate on which a coating film was formed as described above, one year after exposure in Okinawa, the color difference, visual appearance and comprehensive evaluation were made according to the following evaluation methods and evaluation criteria. went. The results are shown in Tables 1, 2 and 3.

(A) Color difference: Color difference system ("CM-2002", Minolta Co., Ltd.) based on the unexposed plate of each test plate.
Manufactured) was used to evaluate ΔE.

(B) Visual observation: Evaluation was carried out with JIS L 0804 gray scale for discoloration (for JIS dye fastness test). It should be noted that the following scores “4” and “5” are levels at which there is no practical problem.

(Evaluation) (Evaluation) 5: No discoloration 4: Slightly discolored 3: Discolored 2: Very discolored 1: Remarkably discolored (c) Overall evaluation: Color difference and appearance were evaluated comprehensively.

(Score) (Evaluation) ○: Practical use ×: Impractical use

[Table 1]

[Table 2]

[Table 3] In Table 1, the coating system, dye type, organic quencher, ultraviolet absorber, and light stabilizer are as follows.

Coating system : Three types shown in FIG. The coating was performed according to the above (1) to (5).

Dye type : D-1; 1: 1 acidic metal-containing complex salt azo dye, yellow dye D-2; 1: 2 acidic metal-containing complex salt azo dye, red dye D-3; non-metal acetic acid salt azo dye Yellow dye (for comparative example) D-4; Phthalocyanine-based blue dye (for comparative example) D-5; Anthraquinone-based blue dye (for comparative example) Organic quencher : Q-1; [2.2'-thiobis ( 4-tertiary octylphenolate)]-2-ethylhexylamine-nickel (II) Q-2; [2.2′-thiobis (4-tertiary octylphenolate)]-n-butylamine-nickel (II) Q -3; 2,4-di-tertiary-butylphenyl-3,5-
Di-tertiary-butyl-4-hydroxybenzoate (for comparative example) UV absorber : U-1; 2- (2'-hydroxy-3 '-, 5'-ditertiary-butyl-phenyl) benzotriazole U- 2; 2,2 ', 4,4'-Tetrahydroxybenzophenone light stabilizer : L-1 is the following chemical formula 3, and L-2 is the following chemical formula 4.

[0068]

Embedded image

[Chemical 4] Incidentally, in the present invention, the color clear coating composition by the top coating composition containing the specific dye is described, but also in the transparent clear coating composition having the composition excluding the specific dye, the ultraviolet rays are generated by the transparent clear coating composition in the same manner as above. There is almost no risk of discoloring or fading the pigment of the base coat through the top coat.

The following embodiments can be mentioned as preferred embodiments of the present invention.

1. Organic nickel-based quenchers are [2.2 '
-Thiobis (4-tertiary octylphenolate)]-2-
Ethylhexylamine-nickel (II), or [2.
2'-thiobis (4-tertiary octylphenolate)]-
A topcoat coating composition and a composite coating film forming method which are at least one of n-butylamine-nickel (II).

2. Organic nickel-based quenchers are [2.2 '
-Thiobis (4-tertiary octylphenolate)]-2-
Ethylhexylamine-nickel (II) top coat composition and composite coating forming method.

3. UV absorber is benzophenone type,
A top coating composition and a composite coating forming method, which are at least one of benzotriazole-based, salicylate-based, acrylic derivative, amide-based, amidine-based, and carbazide-based.

4. A top coating composition and a method for forming a composite coating film, wherein the hindered amine compound is the above formula (I) or formula (II).

5. A top coating composition and a composite coating film forming method, wherein a vehicle is an acrylic resin and / or a polyester resin and an amino resin and / or a blocked isocyanate compound as a cross-linking agent.

6. A top coating composition and a composite coating film forming method, wherein the metal-containing complex salt azo dye is at least one of a 1: 1 type acidic metal-containing complex salt dye or a 1: 2 type acidic metal-containing complex salt dye. 7. The topcoat coating composition is a topcoat coating composition including the following, and a method for forming a composite coating film: (A) 100 parts by weight of vehicle in terms of solid content, (B) solid content relative to 100 parts by weight of vehicle solid content In terms of minutes, 0.1 to 10 parts by weight of a metal-containing complex salt azo dye, 0.5 to 2 parts by weight of an organic nickel quencher, 0.5 to 2 parts by weight of an ultraviolet absorber, and a hindered amine compound. 0.2 to 1 part by weight.

8. The top coating composition and the composite coating forming method, wherein the composite coating forming method is one of the coating systems shown in FIGS.

9. In the top coating composition, the organic nickel quencher is “2.”, the ultraviolet absorber is “3.”, the hindered amine compound is “4.”, and the vehicle is “5.”. And the metal-containing complex salt azo dye is “6.” above, and a method for forming a composite coating film.

[0078]

As described above, in the top coating composition and the composite coating forming method according to the present invention, the non-covalent (isolated) electron pair present in the nitrogen atom or oxygen atom in the ultraviolet absorber or the hindered amine compound is eliminated. It is presumed that the metal-containing complex salt is coordinated with the metal contained in the azo dye and the nickel contained in the organonickel quencher to form an atomic group, that is, a coordination compound or a metal complex. Since this coordination compound has a unique structure, it is considered that when the top coating composition of the present invention is applied on the base coat, the coordination compound is present in a constant sequence in the coating film.

Accordingly, when the top coating composition of the present invention is applied as a top coat, the metal-containing complex salt azo dye is uniformly dispersed in the coating film, and the top coat has transparency and a clear color. A composite coating film having a deep color tone is obtained. Further, since the ultraviolet absorber, the organic nickel-based quencher, and the hindered amine compound that is a light stabilizer are uniformly dispersed in the coating film of the topcoat, ultraviolet rays penetrate the topcoat and discolor the base coat pigment, It is possible to form a composite coating film that has no risk of fading, and that the metal-containing complex salt azo dye in the top coat is exposed to ultraviolet rays and has little risk of discoloration or fading.

Further, by improving the weather resistance of the dye-containing color clear coating film, the color gamut can be expanded.

[Brief description of drawings]

FIG. 1 is a diagram showing a first coating system variation according to the composite coating film forming method of the present invention.

FIG. 2 is a diagram showing a second coating system variation according to the composite coating film forming method of the present invention.

FIG. 3 is a diagram showing a third coating system variation according to the composite coating film forming method of the present invention.

FIG. 4 is a diagram showing a configuration of topcoat coating in the composite coating film forming method of the present invention.

Claims (2)

[Claims] 1. (A) 100 of vehicle in terms of solid content
Parts by weight, and (B) 0.05 to 20 parts by weight of a metal-containing complex salt azo dye and 0.2 to 10 parts by weight of an organic nickel quencher in terms of solid content based on 100 parts by weight of the vehicle solid content. Parts, 0.2 to 10 parts by weight of the ultraviolet absorber, and 0.1 to 5 parts by weight of the hindered amine compound. 2. A color clear coat comprising the topcoat coating composition according to claim 1, wherein the color clear coat is formed on a base coat containing (A) a coloring pigment, a bright pigment, or a bright pigment and a coloring pigment. Or (B) at least one layer of the above-mentioned color clear coat is formed on the transparent clear coat formed by further coating on the above base coat, and further, if necessary, a transparent clear coat is formed on the above color clear coat. A method for forming a composite coating film, which comprises forming at least one coat.