JP2002273334A - Pearlescent coating film forming method and painted object - Google Patents

Abstract

(57) [Abstract] A color change property of an achromatic color at a hue change boundary between a highlight portion perpendicular to a light incident direction and a shade portion oblique to a light incident direction. The present invention provides a method for forming a pearlescent coating film capable of obtaining a coating film exhibiting a design ("achromatic coloring pearl luster") that appears to change slowly, and a coated article obtained by this method. After forming a color base coating layer on a substrate, an interference clear coat layer containing an interference pigment is formed on the color base coating layer, and an achromatic colored resin as a matting agent is further formed thereon. A method for forming a pearlescent coating film for forming a matt top clear coat layer containing fine particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a pearlescent coating film and a coated product obtained by the method.

[0002]

2. Description of the Related Art Brilliant coating films using glitter pigments have been conventionally used for painting automobile outer panels and the like in order to give an excellent appearance, and various coating film forming methods have been proposed. ing. On the glittering coating film, a glossy clear coating film is usually formed as a top coat layer.

[0003] Japanese Patent Application Laid-Open No. 8-38004 describes that a glittering decorative layer is formed on an article, and a translucent protective layer is formed thereon. The coating film on which the translucent protective layer is formed has a calm atmosphere compared to a glossy coating film. However, it has not yet achieved the unique design as shown below.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to form a hue change boundary portion between a highlight portion which is perpendicular to the light incident direction and a shade portion which is oblique to the light incident direction. A method for forming a pearlescent coating film capable of obtaining a coating film exhibiting a design that looks slowly changing with achromatic coloring (hereinafter, referred to as “achromatic pearl luster”), and this method The purpose is to provide the resulting coating.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned problems, and as a result, have reached the present invention. 1. After forming a color base coating layer on a substrate, an interference clear coat layer containing an interference pigment is formed on the color base coating layer, and a gloss containing achromatic colored resin fine particles as a matting agent thereon is further formed thereon. A method for forming a pearlescent glossy coating film for forming an erased top clear coat layer. 2. The method for forming a pearlescent coating film described above, wherein the color of the achromatic colored resin fine particles is white, gray or black. 3. The method for forming a pearlescent coating film, wherein the amount of the achromatic colored resin fine particles in the matte clear coat layer is 1 to 50% by mass. 4. The interference pigment is composed of a mica pigment, a metal oxide-coated alumina flake pigment, a metal oxide-coated silica flake pigment, a metal oxide-coated glass flake pigment, a titanium flake pigment, a hologram pigment, and a flake pigment composed of a cholesteric liquid crystal polymer. The above-mentioned method for forming a pearlescent coating film, which is at least one pigment selected from the group. 5. A coated article obtained by the above-described method for forming a pearlescent coating film.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail.

[0007] The method for forming a pearlescent coating film according to the present invention comprises the steps of forming a color base coating layer on a substrate, and then forming an interference clear coat layer containing an interference pigment on the color base coating layer. , And a matt top clear coat layer containing achromatic coloring resin fine particles as a matting agent is further formed thereon.

Substrates The above-mentioned substrates include metals such as iron, aluminum, copper and alloys thereof; inorganic materials such as glass, cement and concrete; polyethylene resins, polypropylene resins,
Ethylene-vinyl acetate copolymer resin, polyamide resin,
Resins such as acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin, and various plastic materials such as FRP; natural and synthetic materials such as wood and fiber materials (paper, cloth, etc.) and processed products thereof Is mentioned.

In the method for forming a pearlescent coating film of the present invention, first, a color base coating layer is formed on the substrate directly or via a base coating film. When the coated object is an automobile body or an automobile part, it is preferable that the base material is preliminarily subjected to a base treatment such as degreasing or chemical conversion treatment, or an electrodeposition coating or various primer coatings.

Color Base Coating Layer In the pearlescent coating forming method of the present invention, a color base coating layer is first formed on a substrate. This color base coating layer,
Preferably, the layer has a high lightness color gamut having an L value of 65 to 100, and more preferably an L value of 80 to 100. When the content is within this range, the pearl luster is more clearly expressed, so that the L value is 6
If it is less than 5, pearl luster may not be sufficiently exhibited. The L value 100 is an upper limit value as a lightness display. Here, the L value means a lightness index in the Hunter's color difference equation obtained from the tristimulus values X, Y, Z specified in JIS Z8722. The color difference is measured by a spectrophotometer (for example, trade name "SM Computer", manufactured by Suga Test Instruments Co., Ltd.)
Can be measured by

The dry film thickness of the color base coating layer is 1
0-100 μm is preferred. If it is less than 10 μm, it is difficult to hide the underlayer, and if it is more than 100 μm, the appearance of the coating film may be poor. More preferably, it is 20 to 50 μm.

The formation of the color base coating layer is carried out by applying a color base paint to the substrate.
The method for forming the coating film is not particularly limited. However, when the color base paint is a liquid, a spray method, a roll coater method or the like is used, and when the color base paint is a powder, electrostatic coating is preferable. After formation of the color base coating layer, baking may or may not be performed. In this case, a coating film can be obtained by baking at 80 to 160 ° C. for a predetermined time.

The color base paint used for forming the color base coating layer is obtained by dispersing a coloring pigment and / or a brilliant pigment in a vehicle. The type and amount of the color pigment and / or the glitter pigment are selected such that the L value of the coating layer obtained using this color base paint is preferably 65 to 100.

The above-mentioned coloring pigments include organic pigments and inorganic pigments conventionally used for paints.
For example, examples of the organic pigment include azo lake pigments, phthalocyanine pigments, indigo pigments, perylene pigments, quinophthalone pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, metal complex pigments, and the like. Examples of the inorganic pigment include yellow iron oxide, red iron oxide, titanium dioxide, carbon black and the like.
On the other hand, examples of the glitter pigment include various flake pigments, metallic pigments, and the like that have been conventionally used for paints.

The total content of the coloring pigment and the glitter pigment in the paint (mass ratio of the solid content of the pigment to 100 parts by mass of the paint solid content: PWC) is preferably less than 70%.
Less than 50% is more preferred. If it exceeds 70%, the appearance of the coating film deteriorates. Various extender pigments such as talc, calcium carbonate, precipitated barium sulfate, and silica can be used in combination.

The resin for forming a coating film constituting the vehicle contained in the color base paint includes (a) an acrylic resin, (b) a polyester resin, (c) an alkyd resin,
(D) a fluorine resin, (e) an epoxy resin, (f) a polyurethane resin, (g) a polyether resin, and the like, and these can be used alone or in combination of two or more kinds, and preferably an acrylic resin Or it is a polyester resin.

The acrylic resin (a) includes a copolymer of an acrylic monomer and another ethylenically unsaturated monomer. Examples of the acrylic monomer that can be used for the copolymerization include methyl, ethyl, propyl, n-butyl, i-butyl and t-acrylate of acrylic acid or methacrylic acid.
-Butyl, 2-ethylhexyl, lauryl, phenyl,
Esterified products such as benzyl, 2-hydroxyethyl and 2-hydroxypropyl; ring-opened adducts of caprolactone of acrylic acid or 2-hydroxyethyl methacrylate; glycidyl acrylate; glycidyl methacrylate;
Acrylamide, methacrylamide, N-methylolacrylamide, (meth) acrylic esters of polyhydric alcohols and the like can be mentioned. Other ethylenically unsaturated monomers copolymerizable therewith include styrene,
α-methylstyrene, itaconic acid, maleic acid, vinyl acetate and the like.

Examples of the polyester resin (b) include saturated polyester resins and unsaturated polyester resins. Examples thereof include condensates obtained by heating and condensing a polybasic acid and a polyhydric alcohol. Examples of the polybasic acid include saturated polybasic acids such as phthalic anhydride, terephthalic acid and succinic acid, and unsaturated polybasic acids such as maleic acid, maleic anhydride and fumaric acid. As polyhydric alcohol,
Examples include dihydric alcohols such as ethylene glycol and diethylene glycol, and trihydric alcohols such as glycerin and trimethylolpropane. The resin for forming a coating film includes a curable type and a lacquer type, but a type having a curable type is usually used.

When the above-mentioned resin for forming a coating film is of a type having curability, a crosslinking agent such as an amino resin, a (block) polyisocyanate compound, an amine type, a polyamide type, imidazoles, imidazolines, and polycarboxylic acids. And a curing reaction can be carried out at heating or at room temperature. Further, a lacquer type coating film forming resin having no curability can be used in combination with a type having curability.

When the vehicle contains a cross-linking agent, the ratio of the resin for forming a film to the cross-linking agent is 90 to 50% by mass and the content of the cross-linking agent is 10 to 50% by mass in terms of solid content. Preferably, the coating film forming resin is 85 to 60% by mass, and the crosslinking agent is 15 to 40% by mass. If the amount of the crosslinking agent is less than 10% by mass (the amount of the resin for forming a coating film exceeds 90% by mass), the crosslinking in the coating film is insufficient. On the other hand, if the crosslinking agent exceeds 50% by mass (the
), The storage stability of the coating material is reduced and the curing speed is increased, so that the appearance of the coating film is deteriorated.

In addition to the above-mentioned components, the color base coating material comprises a polyamide wax which is a lubricating dispersion of an aliphatic amide, a polyethylene wax which is a colloidal dispersion mainly composed of polyethylene oxide, an anti-settling agent, a curing catalyst, an ultraviolet absorbing agent. Agents, antioxidants, leveling agents, surface conditioners such as silicone and organic polymers, anti-sagging agents, thickeners, defoamers, lubricants, cross-linkable polymer particles (microgels), etc., appropriately added and contained. be able to. These additives can improve the performance of paints and coatings by blending, for example, at a ratio of 15 parts by mass or less, respectively, to 100 parts by mass of the vehicle (based on solid content).

The color base paint may be in any form of organic solvent type, aqueous type or powder type. When the color base paint is an organic solvent-based or water-based paint, the above components are usually provided in a form dissolved or dispersed in a solvent component. The solvent component may be any one that dissolves or disperses the vehicle, and may use an organic solvent and / or water. Organic solvents include those commonly used in the field of coatings. Examples thereof include hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate, cellosolve acetate and butyl cellosolve, and alcohols. When the use of an organic solvent is regulated from the viewpoint of the environment, it is preferable to use water. In this case, an appropriate amount of a hydrophilic organic solvent may be contained.

Interference Clear Coat Layer In the method for forming a pearlescent coating film of the present invention, after forming the above color base coating layer, a wet-on-wet method is used when baking is not performed, or a wet-on method is performed when baking is performed. An interference clear coat layer containing an interference pigment is formed by a dry method. The interference clear coat layer is formed of an interference clear coating containing an interference pigment and a vehicle. The method for forming this coating film and baking are not particularly limited, and the contents described above for the color base coating layer are applied.

The dry thickness of the interference clear coat layer is as follows:
10 to 50 μm is preferred. If it is less than 10 μm, it is difficult to develop pearl luster. More preferably, it is 10 to 30 μm.

Examples of the interference pigment contained in the interference clear paint include mica pigment, metal oxide-coated alumina flake pigment, metal oxide-coated silica flake pigment, metal oxide-coated glass flake pigment, titanium flake pigment,
At least one kind of pigment selected from hologram pigments and flake pigments composed of cholesteric liquid crystal polymers can be used. Preferably, mica pigments are used. Such mica pigments include titanium dioxide, iron oxide and other chromium, on the surface of natural muscovite and synthetic mica.
A pearl mica pigment coated with a thin film of a metal oxide such as cobalt, tin or zirconium to impart a coloring effect, and has a particle size range of 1 to 60 μm, preferably 1 to 40 μm.
and scaly particles having an average particle size of 15 to 25 μm. The interference color of the mica pigment can be adjusted by changing the type and amount (coating thickness) of the metal oxide to be coated.

The content (PWC) of the interference pigment in the interference clear paint is preferably 0.1 to 30%, more preferably 0.5 to 15%. If it is less than 0.1%, pearl luster may not be sufficiently developed, and if it exceeds 30%, the appearance of the coating film may be deteriorated.

As the vehicle contained in the interference clear coating, those described in the color base coating can be used.

The above-mentioned interference clear paint can contain the above-mentioned coloring pigment within a range not to impair the transparency.

The above-mentioned interference clear coating is an organic solvent type,
It may be in aqueous or powder form. The organic solvent type and water-based paint may be of a one-pack type or of a two-pack type such as a two-pack type urethane resin paint.

Matte Top Clear Coat Layer In the method for forming a pearlescent coating film of the present invention, after forming the above interference clear coat layer, if no baking is performed thereon, a wet-on-wet method or baking is performed. In this case, at least one mat top clear coat layer containing achromatic colored resin fine particles as a matting agent is formed by a wet-on-dry method.

The mat clear top clear coat layer is formed of a mat clear top clear coat paint containing achromatic colored resin fine particles as a matting agent. The method for forming this coating film and baking are not particularly limited, and the contents described above for the color base coating layer are applied.

The dry film thickness of the matte clear coat layer is preferably 20 to 50 μm. If it is less than 20 μm, it is difficult to develop pearl luster. More preferably 25 to 45
μm.

As the matting agent used in the mat top clear coat paint, achromatic colored resin fine particles are used.

The achromatic colored resin fine particles are white,
Gray or black colored acrylic resin, polyacrylonitrile resin, polyurethane resin, polyamide resin,
Polyimide resin and the like can be mentioned. The average particle size of the achromatic colored resin fine particles is preferably 10 to 25 μm. If it is less than 10 μm, the effect of developing achromatic pearlescent luster is insufficient, and the feel is too smooth. On the other hand, when it exceeds 25 μm, the surface of the mat top clear coat layer becomes rough, giving a rough texture.

The inorganic fine particles may be used in an amount which does not impair the effect of the achromatic colored resin fine particles. Examples of the inorganic fine particles include fine silica powder, clay, talc, and mica. The average particle size of the inorganic fine particles is preferably from 1 to 5 μm. When the achromatic colored resin fine particles and the inorganic fine particles are used in combination, it is possible to form a composite coating film exhibiting achromatic colored pearl luster in a soft atmosphere. The mass mixing ratio at that time was such that the inorganic particles 0.0
01 to 1 are preferred.

The content of the achromatic colored resin fine particles is preferably 1 to 50% by mass in the matte top clear coat layer. If the amount is less than 1% by mass, the effect of exhibiting achromatic coloring pearl luster may not be obtained, and if it exceeds 50% by mass, the strength of the coating film may be insufficient. More preferably, it is 2 to 40% by mass.

The mat clear top clear paint containing the achromatic colored resin fine particles contains a vehicle. As the vehicle, the vehicle described for the color base paint can be used. In addition, Tokuhei 8-193
No. 15, the combination of the carboxyl group-containing polymer and the epoxy group-containing polymer described in JP-A No. 15-282, disturbed the orientation of the coherent pigment in the lower coating layer when coated by acid rain resistance and wet-on-wet methods. It is preferably used from the viewpoint that it does not exist.

The above matte top clear paint may contain the above-mentioned coloring pigment, extender, modifier,
Additives such as an ultraviolet absorber, a leveling agent, a dispersant, and an antifoaming agent can be blended.

Further, the mat clear top clear coating may be in any form of organic solvent type, aqueous type or powder type. The organic solvent type and water-based paint may be one-pack type or two-pack type such as two-pack type urethane resin paint.

If the interference clear coat layer contains a large amount of interference pigment or a large particle size interference pigment, the matte top clear coat layer may be formed in two or more layers. The pearl luster effect can be improved. When two or more matte top clear coat layers are formed, a matte top clear coat layer is formed on the outermost layer by the matte clear paint containing the carboxyl group-containing polymer and the epoxy group-containing polymer. Is preferred for the same reasons as above.

Coated product The coated product of the present invention is obtained by the above-mentioned method for forming a pearlescent coating film. In this coating, a color base coating layer on a substrate, an interference clear coat layer containing an interference pigment thereon, and a matte top clear coat layer containing the achromatic colored resin fine particles thereon are further formed thereon. I have.

The dry film thickness of the color base coating layer is 1
0-100 μm is preferred, and 20-50 μm is more preferred. The dry film thickness of the interference clear coat layer is 10 to
50 μm is preferable, and 10 to 30 μm is more preferable.
The dry film thickness of the matte top clear coat layer is 20
-50 μm is preferable, and 25-45 μm is more preferable.

A multilayer coating film is formed on the coating. Here, the matte top clear coat layer containing the achromatic colored resin fine particles is a layer that does not hide the lower coating layer, and as a composite effect with the color base coating layer and the interference clear coat layer, these three layers A multi-layer coating film comprising achromatic pearlescent luster.

[0044]

EXAMPLES Next, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, the compounding amount represents a mass part unless there is particular notice. The names of raw materials, paints, and equipment represent trade names unless otherwise specified.

Preparation of base materials in Examples 1 to 13 and Comparative Examples 1 to 2 Dull steel plates (length 300 mm, width 100 mm and thickness 0.8 mm) were treated with a zinc phosphate treating agent ("Surfdyne SD2
000 "(manufactured by Nippon Paint Co., Ltd.), and then a cationic electrodeposition paint (" Power Top U-50 ", manufactured by Nippon Paint Co., Ltd.) was electrodeposited so that the dry film thickness became 25 [mu] m. Next, it was baked at 160 ° C. for 30 minutes to obtain a substrate.

Method of forming a coating film The above-mentioned base material is air-sprayed with the combination shown in Table 1 so as to have a dry film thickness of 30 μm, and baked at 140 ° C. for 30 minutes to form a color base coating film layer. Formed. Coating is performed using an electrostatic coating machine (“Auto
REA ", manufactured by ABB Industry Co., Ltd.) at an atomization pressure of 2.8 kg / cm ² . Then, the interference clear paint A (interference mica pigment: "Iriodin 7225WI"
I (blue), manufactured by Merck Ltd. "
Containing acrylic melamine resin-based clear coating) or interference clear coating B (titanium oxide-coated alumina flake pigment: "Xirallic T-60-23WIII")
(Blue), manufactured by Merck & Co., Ltd.), and spray-coated with an acrylic melamine resin-based clear paint containing 10% by mass in a dry coating film) to a dry film thickness of 15 μm, and set for 3 minutes after coating. The matte top clear paint obtained by adding the achromatic colored resin fine particles of the type and amount shown in Table 1 to the clear paint shown in Table 1 was dried to a film thickness of 35.
It was coated to a thickness of μm, set at room temperature for 10 minutes, and baked at a temperature of 140 ° C. for 30 minutes. The resulting coating film was evaluated for the effect of developing achromatic coloring pearl luster by the following evaluation method, and the results are shown in Table 1.

Color base paint Color base paint 1: Acrylic / melamine resin color base paint (“Olga S-90 Sealer White”, Nippon Paint Co., Ltd., L value: 95) Color base paint 2: Acrylic / melamine resin color base paint (“Olga S-90 light gray ", Nippon Paint Co., Ltd., L value: 85) Color base paint 3: acrylic / melamine resin color base paint (" Olga S-90 Sealer Gray ", Nippon Paint Co., L value: 70) Color base paint 4: Acrylic / melamine resin color base paint (“Olga S-90 Sealer Dark Gray”, manufactured by Nippon Paint Co., Ltd., L value: 40) L value: tristimulus value X specified in JIS Z 8722,
It is a lightness index in the Hunter's color difference formula obtained from Y and Z.

Clear paint Clear paint 1: acrylic / melamine resin (trade name:
"Super Lac O-130 Clear", manufactured by Nippon Paint Co., Ltd., Clear paint 2: carboxyl group-containing polymer and epoxy group-containing polymer ("Macflow O-520 Clear", manufactured by Nippon Paint Co., Ltd.)

Matting agent Matting agent 1: Black coloring acrylic resin, Matting agent 2: Gray coloring acrylic resin, Matting agent 3: White coloring acrylic resin, Matting agent 4: Black coloring polyurethane

Evaluation method Achromatic coloring pearl luster: The film obtained above was viewed from almost directly above (A) and the film was viewed at a bird's-eye angle of about 15 degrees with respect to the test piece (B). The appearance of the hue change at the boundary was visually evaluated. 3 ... A hue change at the boundary between (A) and (B) gradually changes with achromatic coloring. 2 ... A hue change at the boundary between (A) and (B) is achromatic. Those that change slightly slowly with coloring property 1... Those in which the hue change at the boundary between (A) and (B) changes rapidly or does not involve achromatic coloring

[0051]

[Table 1]

As is evident from the results shown in Table 1, in this example, a coating film was formed by the method for forming a pearlescent coating film of the present invention, and a coated product exhibiting achromatic pearlescent luster was obtained. Was. On the other hand, in the comparative example, an achromatic coloring pearl luster was not obtained.

[0053]

As described above, after forming a color base coat layer on a substrate, an interference clear coat layer containing an interference pigment is formed, and then a matte top clear coat layer containing achromatic colored resin fine particles. By forming
It has made it possible to provide a glittering coating film exhibiting an achromatic pearlescent design.

Further, since the coating film obtained by the present invention has an achromatic coloring pearl luster, it is required to have a design property of a vehicle outer plate, a container outer surface, a coil coating, a home appliance, a communication product and the like of automobiles and motorcycles. It is preferably used in painted products.

Continued on the front page F term (reference) 4D075 AE03 CB02 CB06 CB15 DA06 DB02 DB06 DB07 DB12 DB13 DB18 DB20 DB21 DB36 DB38 DB40 DB43 DB47 DB48 DB50 DB53 DB61 DC12 DC13 DC18 DC41 EA07 EA10 EA43 EB16 EB22 EB32 EB33 EB35 EB33 EB35 EB33 EB35 EB35 EC04 EC05 EC07 EC11 EC23 EC54

Claims (5)

[Claims] 1. After forming a color base coating layer on a substrate, an interference clear coating layer containing an interference pigment is formed on the color base coating layer, and achromatic coloring is performed thereon as a matting agent. A method for forming a pearlescent glossy coating film for forming a matt top clear coat layer containing resin fine particles. 2. The coloring of the achromatic colored resin fine particles is white,
The method for forming a pearlescent coating film according to claim 1, which is gray or black. 3. The method for forming a pearlescent coating film according to claim 1, wherein the amount of the achromatic colored resin fine particles in the matte clear coat layer is 1 to 50% by mass. 4. The interference pigment comprises a mica pigment, a metal oxide-coated alumina flake pigment, a metal oxide-coated silica flake pigment, a metal oxide-coated glass flake pigment, a titanium flake pigment, a hologram pigment, and a cholesteric liquid crystal polymer. The method for forming a pearlescent coating film according to any one of claims 1 to 3, wherein the method is at least one pigment selected from the group consisting of flake pigments. 5. A coated article obtained by the method for forming a pearlescent coating film according to any one of claims 1 to 4.