JP2001062391A - Brilliant coating film-forming method and aluminum wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give excellent coating appearance by successively forming a color clear primer coating layer, a brilliant clear coating layer, and a top clear coating layer on a substrate for a road wheel. SOLUTION: A color clear primer coating layer is formed on a substrate for a road wheel, a member to which a tier of an automobile is to be attached and which is produced by processing a metal such as iron, aluminum, magnesium, titanium, or alloy thereof, using a powder color clear coating material containing a coating film-forming resin such as an epoxy resin, a polyester resin, an acrylic resin and the like, a cross-linking agent, a coloring pigment, and the like. On the coating layer, a bright clear coating layer containing a holographic pigment-containing brilliant coating material is formed by a wet- on-wet method or a wet-on-dry method, and further a top clear coating film is formed thereon.

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 glittering coating film and a road wheel base material coated by the method.

[0002]

2. Description of the Related Art Steel wheels, aluminum wheels (alloys), and the like are used as automobile wheels as mounting members for automobile parts such as tires. In particular, aluminum wheels excellent in weight reduction, design properties, corrosion resistance, and the like are frequently used. The aluminum wheel is coated with, for example, a thermosetting acrylic resin-based coloring paint and a thermosetting acrylic resin-based clear coating in a two-coat one-bake or two-coat two-bake system in order to improve design properties. For example, Japanese Patent Application Laid-Open No. H10-157401 describes a coating film formed on the surface of a wheel made of aluminum or an alloy thereof and a coating method thereof.

In this publication, an epoxy powder primer layer is provided on a cutting surface of an aluminum wheel, an acrylic solvent color layer is provided thereon, and an acrylic clear layer is provided thereon.
They are formed in order. Here, there is no specific description about the acrylic solvent color layer. In recent years, various brighteners such as, for example, aluminum flakes and interference mica pigments have been studied for imparting design properties. By applying such a glitter material to the above-mentioned acrylic solvent color layer, it is possible to enhance the design of the wheel, but a new design is required. As such a method, a so-called skeleton finish in which the feel of the material of the base material can be visually recognized is given. On the other hand, as a material for imparting designability, Japanese Patent Application Laid-Open
JP-A-506379 discloses a hologram pigment and a coating material containing the same.

[0004]

However, when painting an aluminum wheel, it is necessary to hide the roughness of the surface roughness of the base material. It is necessary to prevent the film from protruding from the film, and a method for forming a coating film different from the application to the vehicle body described in the above publication is required.

[0005] Therefore, the problem to be solved by the present invention is:
Skeleton finishing is possible, the surface roughness of the road wheel substrate is rough, the roughness of the substrate is concealed, the appearance of the coating film without protrusion from the coating film of the hologram pigment itself is good,
On the other hand, on the design side, the hologram pigment is mixed into the clear paint, which has a large prism effect, and the hologram clear coating layer, which changes to iridescent depending on the angle at which each hologram pigment is viewed, and the color clear base layer below it An object of the present invention is to provide a glitter coating film forming method for providing a glitter coating film exhibiting a deep glitter feeling by expressing a design by a composite color with a coating layer, and an aluminum wheel coated by this method.

[0006]

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. On the base material for road wheels, the following (1) to (3)
A method for forming a glittering coating film by sequentially forming a coating film layer. (1) a color clear primer coating layer formed from a powder coating, (2) a glitter clear coating layer formed from a hologram pigment-containing glitter coating (hereinafter, referred to as a hologram clear coating layer), (3) Top clear coating layer 2. The following (1 ') ~
(3) A method for forming a brilliant coating film by sequentially forming a coating film layer. (1 ′) clear primer coating layer formed from powder coating, (1 ″) color clear base coating layer, (2) hologram clear coating layer, (3) top clear coating layer ) The top clear coating layer is composed of (3-1) a first clear coating layer and (3-2) a second clear coating layer.
1) The above-described glittering coating film forming method, wherein the first clear coating film is formed by a wet-on-wet two-coat one-bake method. 4. The above aluminum wheel obtained by the above glittering coating film forming method.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail. The first glittering coating film forming method of the present invention comprises: (1) a color clear primer coating layer formed from a powder coating, (2) a hologram clear coating layer, 3) A method of forming a glittering coating film in which a top clear coating layer is sequentially formed. The method for forming a glittering coating film according to the second aspect of the present invention comprises the steps of:
Clear primer coating layer formed from powder coating,
This is a method of forming a glittering coating film in which (1 ″) a color clear base coating layer, (2) a hologram clear coating layer, and (3) a top clear coating layer.

In the method for forming a glittering coating film of the present invention,
A color clear layer is formed below the hologram clear coating layer. In the first method, the color clear layer is a color clear primer coating layer formed from a powder coating, and in the second method, the color clear primer coating layer is formed on the clear primer coating layer formed from the powder coating. A clear base coating layer was formed.

[0009]Base material  As the base material, iron, aluminum, magnesium,
Automobiles processed from metals such as titanium or their alloys
For road wheels, which are members for mounting tires such as
It is a substrate. In the glitter coating film forming method of the present invention,
A primer coating layer composed of a powder coating is directly applied to the base material.
To be formed, but beforehand by degreasing, chemical conversion treatment, etc.
Ground treatment, and in the case of iron road wheels, clear
-It is preferable to form an electrodeposition coating film in advance.

[0010]Clear primer formed from powder coating
ー Formation of coating layer  Primer coating layer in glittering coating forming method of the present invention
Consists of a clear coating that does not hide the base. This chestnut
Texture of the road wheel
Are visible in the finally obtained coating film.

In the first method of the present invention, the primer coating layer is a color clear primer coating layer, and in the second method, the primer coating layer is a clear primer coating layer. Here, the clear primer coating film layer includes a color clear primer coating film layer.

The color clear primer coating layer is
It is formed by a powder color clear paint containing a color pigment. The powder color clear paint containing a color pigment for forming the color clear primer coating film layer is an epoxy resin, a polyester resin, a film-forming resin composed of an acrylic resin, a cross-linking agent, an amount in a range that does not impair transparency. It is a powder coating obtained by blending and kneading a color pigment and, if necessary, a curing catalyst, a surface conditioner, and other additives, and pulverizing and classifying.

The epoxy resin is preferably a compound having two or more oxirane groups in the molecule. Specifically, for example, glycidyl ester resins, glycidyl ether resins such as condensation products of bisphenol A and epichlorohydrin, alicyclic epoxy resins, linear aliphatic epoxy resins, brominated epoxy resins, phenol novolaks Epoxy resin, cresol novolak epoxy resin, and the like. Examples of the epoxy resin curing agent include an epoxy resin having a phenolic hydroxyl group, an amine-based curing agent, dicyandiamide, imidazoles, and imidazolines. Examples of the bisphenol type epoxy resin include, for example, Epicoat 828, Epicoat 1001, Epicoat 100
4, Epicoat 1007, Epicoat 1009 (all manufactured by Shell Chemical Co., Ltd.), and those obtained by chain-extending these with an appropriate chain extender can also be used. As the acrylic resin, polyester resin, coloring pigment and the like, those described later in the formation of the color clear base coating layer can be used.

Further, the clear primer coating layer in the second method of the present invention can be formed by either a powder color clear coating containing a coloring pigment or a powder clear coating not containing a coloring pigment. As the powder color clear paint containing the coloring pigment, the same one as described above can be used. On the other hand, the description of the powder color clear paint containing the color pigment can be applied to the powder clear paint containing no color pigment, except for the presence or absence of the color pigment. When the clear primer coating layer in the second method of the present invention is a color clear primer coating layer formed from a powder color clear coating containing a coloring pigment, it is combined with the color clear base coating layer located above. Thereby, the variation of the design can be increased.

[0015] The dry film thickness of the primer coating layer is from 30 to 2 from the viewpoint of coating smoothness, corrosion resistance and chipping resistance.
It is preferable that the coating be performed so as to be 00 μm, particularly 50 to 150 μm. By using a powder coating material for forming the primer coating film layer, it is possible to cover the roughness of the road wheel base material having a rough surface roughness and to smooth the coating film. Note that an electrostatic coating method is used for applying the powder coating, and can be performed using a known electrostatic coating machine or the like.

[0016]Formation of color clear base coating layer  Color clear base coating film in the second method of the present invention
The layer consists of a clear coating that does not mask the substrate. This
By using the rear coating film, the base material of the road wheel
Texture is visible in the final coating film
You. The color clear base coating layer is a coating forming resin
Vehicle and hologram, and optionally a crosslinker
Used for middle coat or top coat other than ram pigment
Glitter pigments (hereinafter, glitter pigments) and / or
Disperse the color pigment in an amount that does not impair transparency.
It may be formed by the obtained solvent type clear paint,
Or powder type clear obtained by kneading, grinding and classifying
It may be formed by a paint. As solvent type clear paint
May use a one-pack type paint or a two-pack type urethane resin
A two-pack type resin such as a paint may be used. Of the above components
In addition, a curing catalyst, a surface conditioner, and other additives
Is also good.

In the color clear base paint used for forming the color clear base coating layer in the present invention, (a) an acrylic resin and (b)
Polyester resin, (c) alkyd resin, (d) fluororesin, (e) epoxy resin, (f) polyurethane resin,
(G) Polyether resins and the like can be mentioned, and these can be used alone or in combination of two or more, and are preferably acrylic resins and polyester resins.
(A) Examples of the acrylic resin include a copolymer of an acrylic monomer and another ethylenically unsaturated monomer. Examples of the acrylic monomer that can be used in the above copolymerization include methyl, ethyl, propyl, n-butyl, i-butyl, and t-acrylate of acrylic acid or methacrylic acid.
Esterified products such as butyl, 2-ethylhexyl, lauryl, phenyl, benzyl, 2-hydroxyethyl and 2-hydroxypropyl, acrylic acid or methacrylic acid 2
-Ring-opened adducts of caprolactone of hydroxyethyl, glycidyl acrylate, glycidyl methacrylate, acrylamide, methacrylamide and N-methylolacrylamide, (meth) acrylic esters of polyhydric alcohols and the like. Other ethylenically unsaturated monomers copolymerizable therewith include styrene, α-methylstyrene, itaconic acid, maleic acid, vinyl acetate and the like. (B) Examples of the polyester resin include a saturated polyester resin and an unsaturated polyester resin, and examples thereof include a condensate obtained by heating and condensing a polybasic acid and a polyhydric alcohol. Examples of the polybasic acids include saturated polybasic acids and unsaturated polybasic acids. Examples of the saturated polybasic acids include phthalic anhydride, terephthalic acid, and succinic acid. Examples of the acid include maleic acid, maleic anhydride, fumaric acid and the like. Examples of the polyhydric alcohol include dihydric alcohols and trihydric alcohols, and examples of the dihydric alcohol include ethylene glycol and diethylene glycol. Examples of the trihydric alcohol include:
Glycerin, trimethylolpropane and the like can be mentioned.
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.

In the case of a type having curability, amino resins, (block) polyisocyanate compounds, amines, polyamides, imidazoles, imidazolines,
It is used by mixing with a crosslinking agent such as a polyvalent carboxylic acid, and the curing reaction can proceed at heating or at room temperature. Also,
It is also possible to use a non-curable type coating film forming resin in combination with a curable type.

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 weight and the content of the cross-linking agent is 10 to 50% by weight in terms of solid content. Preferably, the coating film forming resin is 85 to 60% by weight, and the crosslinking agent is 15 to 40% by weight. If the crosslinking agent is less than 10% by weight (the resin for forming a coating film exceeds 90% by weight), the crosslinking in the coating film is not sufficient. On the other hand, when the cross-linking agent exceeds 50% by weight (the resin for forming a coating film is 50% by weight)
), The storage stability of the coating composition is reduced and the curing speed is increased, so that the appearance of the coating film is deteriorated.

The above-mentioned color clear base paint is conventionally used as a brilliant pigment for paints, for example, aluminum flake pigment, colored aluminum flake pigment, alumina flake pigment, graphite pigment, mica pigment, metal titanium flake, It can contain stainless flake, plate-like iron oxide, phthalocyanine flake, metal-plated glass flake, and the like.

The above-mentioned color clear base paint can also contain a color pigment. As such pigments, conventionally used for paints, for example, as organic pigments, azo lake pigments, phthalocyanine pigments, indigo pigments, perylene pigments, quinophthalone pigments, dioxazine pigments, quinacridone pigments , Isoindolinone pigments, metal complex pigments and the like, and as the inorganic pigments, graphite, yellow iron oxide, red iron oxide,
Examples include titanium dioxide and carbon black. Various extender pigments such as talc, calcium carbonate, precipitated barium sulfate, and silica can be used in combination. The content of the brilliant pigment, the coloring pigment, and the extender is an amount that does not hide the base.

The color clear base coating material may further comprise, in addition to the above components, polyamide wax as a lubricating dispersion of an aliphatic amide, polyethylene wax as a colloidal dispersion mainly composed of polyethylene oxide, an anti-settling agent, a curing catalyst, UV absorbers, antioxidants, leveling agents, surface conditioners such as silicone and organic polymers, anti-sagging agents, thickeners, defoamers, lubricants, cross-linkable polymer particles (microgels), etc. Can be contained. The performance of paints and coatings can be improved by blending these additives in a proportion of, for example, 15 parts by weight or less with respect to 100 parts by weight of the vehicle (based on solid content).

When the color clear base coating composition is a solvent type, the above components are usually provided in a form dissolved or dispersed in a solvent. Any solvent may be used as long as it dissolves or disperses the vehicle, and an organic solvent and / or water may be used. Examples of the organic solvent include those commonly used in the field of coatings. For example,
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.

The dry thickness of the color clear base coating layer is preferably from 10 to 100 μm. 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, 20-50μ
m.

[0025]Formation of hologram clear coating layer  Hologram clear in the glittering coating film forming method of the present invention
In the first method, the coating layer is formed by the above-mentioned color clear plug.
On the immersion coating layer, and in the second method, the color
-On the clear base coating layer, a hologram pigment and
Contains brilliant pigment and / or coloring pigment as required
Hologram pigment-containing glitter paint (hereinafter referred to as hologram)
Clear paint).

The hologram clear coating layer may be formed by a solvent type paint or a powder type paint. As the solvent-type paint, a one-pack paint may be used, or a two-pack paint such as a two-pack urethane resin paint may be used. The vehicle, the brilliant pigment other than the hologram pigment, the coloring pigment, and other components contained in the hologram clear paint are the same as those described in the color clear base coating layer.

The dry film thickness of the hologram clear coating layer is preferably from 10 to 100 μm. If it is less than 10 μm, a hologram feeling cannot be sufficiently exhibited, and if it exceeds 100 μm, the appearance of the coating film may be insufficient. More preferably, it is 20 to 50 μm.

The hologram pigment has the property that interference fringes corresponding to the wavefront of light from an object are formed as a hologram image. These hologram pigments can be formed by forming a thermoplastic resin layer on the surface of a support film serving as a substrate, forming a hologram layer having irregularities of about 2500 ° on the surface, laminating a thin film, A hologram base plate having a relief hologram formed thereon is pressed against an ultraviolet or electron beam-curable resin layer on the surface of the substrate, and the ultraviolet or electron beam-curable resin layer is cured after pressing. Furthermore, on the hologram surface, if necessary, various metals are deposited and used,
A protective film may be laminated on the surface and used. The hologram layer and the support film may be colored by a known method.

The hologram pigment consists of a hologram layer formed on the support film.
Flakes of any size obtained by glittering or the like are used. The size is processed to about 10 to 1000 μm according to the application. From the appearance of the coating,
10 to 500 μm is preferred. As the flake shape, a circular shape, an elliptical shape, a square shape, or the like can be used according to the purpose.

As these commercially available hologram pigments, diamond holograms HG-type, HG-S type, HG-E
P type, diamond crystal color (all manufactured by Dia Kogyo Co., Ltd.), GEOMETRIC PIGMENTS (manufactured by Spectratech) and the like.

The content (PWC) of the hologram pigment in the hologram clear coating composition is from 0.01 to 3
0% is preferable, and 1 to 15% is more preferable. 0.01
%, The hologram feeling is reduced, and if it exceeds 30%, the appearance of the coating film may be reduced.

[0032]Formation of top clear coating layer  In the first and second methods of the present invention, a hologram
After forming the clear coating layer, top clear
Form a coating layer. Top clear coating layer in this case
Is a clear colorless clear
Iwayu, which has a semi-transparent
It may be a turbid clear coating film. Hologram clear
-To form a top clear coating layer on the coating layer
Better gloss and prevent hologram pigment protrusion
be able to. Is the top clear layer a clear paint?
The clear paint is used for top coat
Can be cited as those commonly used as described above,
It is possible to use a mixture of a thermosetting resin and a crosslinking agent.
it can.

As a preferred embodiment of the present invention, the above (3)
Comprises a (3-1) first clear coating film and (3-2) a second clear coating film, wherein the (2) hologram clear coating layer and the (3-1) The first clear coating film may be formed by a wet-on-wet two-coat one-bake method. This makes it possible to obtain a glittering coating film having a high smoothness and a sense of depth. In this case, it is more preferable to apply the resin system used for the hologram clear coating film layer as the clear coating material for the first clear coating film layer formed wet-on-wet in order to improve the appearance of the coating film. The paint used for forming the second clear coating layer is not particularly limited.

[0034] These clear paints may be used, if necessary,
As long as the transparency is not impaired, coloring pigments, extender pigments,
Additives such as a modifying agent, an ultraviolet absorber, a leveling agent, a dispersant, and an antifoaming agent can be blended. Further, the top clear coating layer may be formed from a solvent type paint,
It may be formed from a powder type paint. As solvent type paint,
One-pack type paint may be used, or two-pack type paint such as two-pack type urethane resin paint may be used.

The dry film thickness of the top clear coating film layer of the present invention is preferably from 30 to 400 μm, and if it is outside this range, the appearance of the coating film may be insufficient. More preferably 5
0 to 200 μm. In the second method of the present invention, when the hologram clear coating layer and the first clear coating layer are formed by wet-on-wet, the dry film thickness of the first clear coating layer is preferably 20 to 100 μm. ,
The dry film thickness of the second clear coating layer is preferably from 30 to 400 μm, and if it is outside this range, the appearance of the coating film may be insufficient.

[0036]Bright coating film forming method  In the glitter coating film forming method of the present invention, the base material,
Form a clear primer coating layer consisting of powder coating,
Wet on wet (W
/ W) method or wet-on-dry (W / D) method
Color clear base coating layer or hologram
A rear coating layer can be formed. The above W / W
After coating the base, dry by air drying etc., not cured
This is a method of applying to the undercoated film in a state or semi-cured state.
On the other hand, the above-mentioned W / D method means that a base coat is baked.
This is a method of applying to a cured undercoat film. like this
After forming the color clear base coating layer,
Color clear by the W / W method or W / D method
The color clear base coating layer or
A hologram clear coating layer is formed.

On the hologram clear coating layer thus formed, at least one top clear coating layer is formed as a top coat layer. The method of forming each coating layer is not particularly limited, but when applying a solvent type paint, a spray method, a roll coater method or the like is used, and when applying a powder type paint, electrostatic coating is preferable. It is also possible to paint. Drying conditions are 80-16
It is baked at 0 ° C. for a predetermined time to obtain a coating film.

[0038]aluminum foil  The coated aluminum wheel of the present invention is provided with
It is obtained by a film forming method, and (1) powder coating
A color clear primer coating layer formed from
(2) Hologram clear coating layer, (3) Top clear
-A multilayer coating film composed of a coating film layer is formed. Also on
The multi-layer coating film layer is formed of a (1 ') powder coating
Year primer coating layer, (1 ") color clear base
Coating layer, (2) hologram clear coating layer, (3) top
It may consist of a clear coating layer. these
Aluminum wheels with multi-layer coatings of
Is a smooth coating film that conceals the
Rear coating layer and lower color clear primer coating layer
Or the composite color with the color clear base coating layer
In addition to expressing the craftsmanship, the texture of the aluminum wheel is visible
Unprecedented skeleton finish
It has a brilliant feeling.

[0039]

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 weight part unless there is particular notice.

[0040]Examples 1 to 17, Comparative Examples 1 to 3 Preparation of hologram clear coating composition  Acrylic resin (styrene / methyl methacrylate / ethyl
Methacrylate / hydroxyethyl methacrylate /
Methacrylic acid copolymer, number average molecular weight about 20,000,
(Hydroxyl value 45, acid value 15, solid content 50% by weight)
Min resin (trade name: "Uban 20SE", Mitsui Chemicals, Inc.)
(Manufactured by Corporation, solid content 60% by weight)
The hologram pigment is added to the vehicle obtained by blending at a weight ratio.
A (average particle diameter 100 μm, trade name: “Diamond hologram”
HG-S5EP ", manufactured by Diamond Industry Co., Ltd.), hologram pigment
B (average particle size 50 μm, trade name: “375 GEOMET”
RICPIGMENTS ”, manufactured by Spectratech)
It was blended in the ratio shown in Table 1. Then, the organic solvent (tolue
Weight ratio of ethylene / xylene / ethyl acetate / butyl acetate = 70
/ 15/10/5) and the appropriate viscosity of the coating with a stirrer
Stir and mix so that the hologram clear paint composition
Was prepared. However, in the comparative example, the hologram pigment was used instead of the hologram pigment.
In addition, in Table 1, white mica pigment indicated by C
(Iriodin 103WII, manufactured by Merck) was used.

[0041]Base material  Chromate treatment for aluminum alloy (AC4C) wheels
(Product name: "Al Surf 1000", Nippon Paint Co., Ltd.
The product was processed using

[0042]Formation of clear primer coating layer  Form the following clear primer coating layer on the above substrate
You. Powder color clear paint as clear primer
(Product name: "Powdax A-400 Green Clear"
-", Manufactured by Nippon Paint Co., Ltd.)
Paint and bake at 160 ° C for 20 minutes
-A primer coating layer was formed, and this was used as a substrate 1. Up
A colorless and transparent powder paint
Rear paint (trade name: "PAUDAX A-400 Clear"
-", Manufactured by Nippon Paint Co., Ltd.)
A coating layer was formed, and this was used as a substrate 2. Also for the comparative example
Solvent type clear paint (trade name: "Super Rack"
M-90 Clear ", manufactured by Nippon Paint Co., Ltd.)
Is painted to a thickness of 50 µm and baked at 140 ° C for 20 minutes.
Form a clear primer coating layer and apply it to the substrate
It was set to 3.

[0043]Formation of color clear base coating layer  Color clear base paint B1 (trade name: "Super La
M-90 Green Clear ", manufactured by Nippon Paint Co., Ltd.)
Or color clear base paint B2 (trade name: "Sue
Parrack M-90 Silver Metallic Clear ", Sun
(Made by Hon Paint Co.) so that the dry film thickness becomes 30 μm.
Spray coating on the substrate 1, 2 or 3
Bake for 0 minutes to form a color clear base coating layer
Was. However, in Examples 1 to 3, the color clear base coating was performed.
No film layer was formed.

[0044]Hologram clear coating layer and topcoat
Formation of rear coating layer  The base material on which the color clear base coating layer was formed,
A coating film was formed using the combination of paints shown in Table 1 below. Example 1
~ 7, 11, 12, 14, 15, 17 and Comparative Examples
Apply the previously prepared hologram clear paint to a dry film thickness of 30μ.
m. Then wet on wet
(In Table 1, described as W / W) or baked at 140 ° C for 20 minutes
After the application, use the following clear paint and solvent-based paint.
Has a dry film thickness of 50 μm, and the powder film paint has a dry film thickness of 50 μm.
Form a top clear coating layer to 100 μm
did. Table 1 shows the baking conditions for the top clear coating layer.
Performed at the indicated temperature for 20 minutes. However, Examples 8 to 10 and 1
3 and 16 form a hologram clear coating layer,
Wet-on-wet and first paint with clear paint 3C
Forming a rear coating layer to a dry film thickness of 50 μm,
Dry coating film thickness of second clear coating layer with clear coating material 3A
It was formed to have a thickness of 50 μm. The baking condition is 2 hours.
At 0 minutes, the temperatures are shown in Table 1. The brilliancy of the resulting coating film
And the appearance of the coating film were evaluated by the following evaluation methods, and the results are shown in Table 1.
You. 3A: Solvent type acrylic resin clear paint (trade name:
"Super Rack 5000AW-10 Clear", Japan
Paint Co., Ltd.) 3B: Powder type clear paint acrylic resin
Fat-based clear paint (trade name: "Powax A-400
Clear ", manufactured by Nippon Paint Co., Ltd.) 3C: Solvent type acrylic
Resin-based clear paint (trade name: "Super Rack 50
00AW-2 Clear ", manufactured by Nippon Paint Co., Ltd.
(The same resin-based paint as the resin of the clear paint)
You.

[0045]Evaluation method  Coating appearance: Visual evaluation of the appearance of the aluminum coating
Valued. 5 ... The texture of aluminum can be visually recognized, skeleton finish and light
Recognized 4 ... The texture of aluminum can be visually recognized, and the skeleton finish
It is possible 3… Slightly visible aluminum texture, skeleton finish
Slight unevenness 2 Skeleton with almost no visible aluminum texture
Non-uniform finish 1. Skeleton finish with no visible aluminum texture
Not recognized Glitter: The prism effect of the coating film is large, and hologram pigment
Each one of them has a radiance that changes into a rainbow color depending on the viewing angle
It was evaluated visually. 5: The above-mentioned glitter is remarkably recognized and there is also a sense of depth. 4 ... The above-mentioned glitter is noticeably recognized. 3 .... The above-mentioned glitter is recognized. 2 .... The above-mentioned glitter is somewhat recognized. Absent

[0046]

[Table 1]

As is evident from the results in Table 1, Examples 1 to 17 are aluminum wheels obtained by the coating film forming method of the present invention, which have a skeleton finish, a good coating appearance and a holographic feeling. Bright feeling was expressed. On the other hand, Comparative Example 1
In Examples 2 and 3, a white mica pigment was used in place of the hologram pigment, so that a brilliant feeling having a hologram feeling was not exhibited. Further, in Comparative Example 3, since the solvent type paint was used as the primer, the roughness of the base material of the aluminum wheel was not concealed, and the result that the coating film appearance was not good was obtained.

[0048]

According to the present invention, since the entire coating layer is composed of a clear coating layer, the appearance of the skeleton finish can be visually recognized so that the texture of the base material can be visually recognized, and the hologram pigment is further incorporated into the clear coating. By doing so, a prism effect of the obtained coating film is large, and a brilliant coating film forming method in which each of the hologram pigments has a brilliant color that changes to iridescent depending on the viewing angle, and an aluminum wheel coated by the method. Made available. In the glittering coating film forming method of the present invention, further, by forming the hologram clear coating layer and the clear coating layer in a wet-on-wet manner, a multi-layer coating exhibiting a higher smoothness and a glittering property with a deeper feeling. A membrane can be obtained. Note that the coating film obtained by the present invention exhibits the above-mentioned brilliant feeling, and thus is preferably used for aluminum wheels for vehicles and the like.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsumi Nugu, Inventor 4-1-1-15 Minamishinagawa, Shinagawa-ku, Tokyo Japan Paint Co., Ltd. (72) Toru Shimizu 5-9-1, Yobancho, Chiyoda-ku, Tokyo Topy Corporation (72) Inventor Takayuki Sato 5-9, Yonbancho, Chiyoda-ku, Tokyo Topy Industries, Ltd. (72) Tatsuya Oguri 5-9, Yonbancho, Chiyoda-ku, Tokyo Topy Industries, Ltd. F-term (reference) 4D075 AE03 AE06 CB04 DB07 DC13 EA02 EA41 EA43

Claims (4)

[Claims] (1) On a road wheel substrate, the following (1)
A glittering coating film forming method of sequentially forming the coating layers of (1) to (3). (1) a color clear primer coating layer formed from a powder coating, (2) a glitter clear coating layer formed from a hologram pigment-containing glitter coating, and (3) a top clear coating layer. 2. A method for forming a glittering coating film, comprising sequentially forming the following coating layers (1 ') to (3) on a base material for a road wheel. (1 ′) a clear primer coating layer formed from a powder coating, (1 ″) a color clear base coating layer, (2) a brilliant clear coating layer formed from a hologram pigment-containing brilliant coating, (3) ) Top clear coating layer 3. The method according to claim 2, wherein (3) the top clear coating layer is (3)
-1) a first clear coating film and (3-2) a second clear coating film, and the formation of the (2) bright clear coating film layer and the (3-1) first clear coating film is wet. The glittering coating film forming method according to claim 1, wherein the glittering coating film is formed by an on-wet two-coat one-bake method. 4. An aluminum wheel obtained by the method for forming a glittering coating film according to claim 1.