JPS6044028B2 - How to apply metallic powder paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for applying a metallic powder coating characterized by using a thermal spraying device (hereinafter referred to as a thermal spray gun).

More specifically, metallic powder coating is applied by using a thermal spray gun to undercoat a thermosetting powder coating containing a foil pigment or a foil pigment and a coloring agent, and then topcoating and baking a thermosetting transparent coating. Regarding the method. Unlike conventional solvent-based paints and water-based paints, powder paints do not pollute the air or water due to solvents, so their use is rapidly increasing as they are the most effective anti-pollution measure in painting.

There are various methods for applying powder coatings, such as fluidized dipping, electrostatic dynamic dipping, and electrostatic spraying, but electrostatic spraying has the best coating performance and is the most efficient, so it is widely adopted. . However, when a metallic powder paint containing a foil-like pigment is electrostatically sprayed, since the pigment is foil-like, an electric charge accumulates at the tip of the foil piece, and due to the electrostatic effect, the thin foil as shown in Figure 1 is applied. The pieces will be oriented perpendicularly to the surface to be coated, and the coating will not have a metallic feel.

This phenomenon is not improved even if the foil-like pigment is melt-mixed with the resin component to form a powder coating; rather, the foil-like pigment is destroyed by the melt-mixing, resulting in a gray and cloudy coating. In any case, only a painted surface with no metallic appearance was obtained, which was completely different from the beautiful metallic paint film obtained with conventional solvent-based paints. From this point of view, for undercoating containing foil pigments or foil pigments and colorants, conventionally used solvent-based paints, non-aqueous dispersion paints, water-soluble paints, etc. are used, and only for topcoating. A method of electrostatic spraying of transparent powder paint has been proposed, but when considered from the standpoint of pollution-free painting using powder paint, the above proposal deviates from the essence. The present invention has been made as a result of intensive research into the above-mentioned problems and has solved the conventional drawbacks, and provides a method for obtaining a coating film having an extremely good metallic appearance using a powder coating.

That is, in the present invention, a metallic powder coating obtained by dry mixing a thermosetting resin powder or a thermosetting resin powder containing a colorant with a foil-like pigment is used as an undercoat using a thermal spray gun, and then a transparent coating is applied. This method involves applying a top coat of paint and then baking and baking.

As a top coat, transparent powder paints are preferable from the standpoint of pollution control, but conventional solvent-based, non-aqueous dispersion,
Thermosetting clear paints such as water-soluble alkyd resins, acrylic resins, and polyester resins can also be used. In the present invention, as shown in FIG. 2, since the foil-like pigments are arranged parallel to the surface to be coated and are not disordered, a uniform coated film with a beautiful metallic feel can be obtained.

Furthermore, since it is applied in a molten state and there is no electrostatic repulsion, it has the best application efficiency. Furthermore, if the use of paint solvents is regulated as part of pollution control measures, a high quality level can be ensured as a metallic paint, which is extremely advantageous in terms of product planning. The powder coating used in the present invention includes:
All paints whose vehicles are thermosetting resins such as acrylic resins, epoxy resins, and polyester resins can be used, and examples of the acrylic resins include Aromatex PD-2300, PD-2310, and PD-12.
7, PD1286, (all product names, manufactured by Mitsui Toatsu Co., Ltd.)
, Fine Index A-243, A-534, (manufactured by Dainippon Ink Co., Ltd.), etc. Polyester resins include Fine Index M-6100, M-6102, (
The above product names are manufactured by Dainippon Ink Co., Ltd.), Kleran U-15
02, product name, manufactured by Bayer Co., Ltd.), ER-6600,
ER-6610, (trade names manufactured by Nippon Ester Co., Ltd.), GV-100, GV-7001 (trade names manufactured by Toyobo Co., Ltd.), etc., and epoxy resins such as Epicote 1002, 1004, 10007, (The above product names,
manufactured by Shell Co., Ltd.), Araldite 6084, 6071,
(The above product names are manufactured by Ciba Geigy Co., Ltd.), etc., and the resin can be selected as appropriate depending on the application.

Examples of the foil-like pigment used in the present invention include aluminum powder or foil, copper powder or foil, tin foil, mica. There are metallic and non-metallic pigments such as powder and vapor-deposited foil.For example, Alpaste 1109MB11100 is an aluminum pigment.
Processed mica such as MA11100N1 and high sparkle aluminum (trade name, manufactured by Toyo Aluminum Co., Ltd.) include Iriodin (trade name, manufactured by West German Merck Co., Ltd.), Pearl Afflair NFLO4 (trade name, manufactured by DuPont Co., Ltd., USA), etc. ), Pearl Grace (product name, Nihon Koken Co., Ltd.)
As the vapor-deposited aluminum foil, Elg Silver (trade name, manufactured by Oike Kogyo Co., Ltd.) is used.

Examples of the thermal spraying apparatus used in the present invention include a plasma spraying apparatus manufactured by Sealectro (USA) and an SNM thermal spraying apparatus for plastics manufactured by SNM (France).

Further, the coating equipment used for the top coating of the present invention includes an electrostatic spraying equipment conventionally used for powder coatings, and various equipments conventionally used for conventional type paints as well.

In the present invention, the undercoat is applied by welding to a film thickness of 40 to 100 μm, and the top coat is applied to a film thickness of 20 to 150 μm.

For powder coatings, it is possible to electrostatically spray the semi-melted surface immediately after thermal spraying the basecoat, but with conventional topcoats, after the basecoat is baked, the coated surface has to reach room temperature. Paint later. Baking of powder paint is 150℃~22℃
Baking is completed at a temperature of 0° C. for 15 to 45 minutes, but for conventional top coats, the baking conditions for each top coat may be used.
Hereinafter, the present invention will be specifically explained using examples.

However, all parts in the examples are parts by weight. Example 1 A: Preparation of undercoat powder coating (thermosetting polyester containing aluminum powder) Relan U-502: 7 parts, Clelan U-1 (curing agent, trade name, manufactured by Bayer Co., Ltd.): 25 parts, Araldite 6084: 3 parts, Modaflow (surface conditioner, trade name, manufactured by Monsanto): 1 part, Cyanine Blue Master Color (colorant, 30% pigment dispersion of Araldite 6084): 1 part, in a Henschel mixer. The mixture was dry mixed for 1 minute, and then melt-kneaded using a Busco Kneader PR-46 at a barrel temperature of 70°C and a screw temperature of 65°C.

The obtained pellets were finely pulverized in a hammer mill and
It was sieved through a wire mesh screen. Parts of Pearl Afflare NF-104 were added to 10 parts of the product that had passed through the wire mesh, and dry mixing was performed again for 1 minute using a Henschel mixer, and coarse particles were sieved through a 150-mesh wire mesh to prepare an undercoat powder paint. Preparation of clear top coat powder paint (thermosetting polyester) Relan U-502:7 (2), Clelan U
-1: 25 parts, Araldite 6071: 3 parts, EAB-
551-02 (cellulose resin, trade name, manufactured by Eastman Kodatsu). 1 part of Modaflori and 1 part of Modaflori were dry mixed, melt-kneaded, crushed, and sieved according to the above procedure to prepare a top coat powder transparent paint.

C. A steel plate (a) on which the undercoat powder paint was treated with zinc phosphate using Bonderite #137 (trade name, manufactured by Nippon Parkerizing Co., Ltd.). 8 x 70 x 1507 wt) using a plasma spray gun manufactured by Sealectro (USA) to obtain a semi-cured coating film with a film thickness of 60 μm.

Subsequently, a clear top coat powder was sprayed using a 720 type electrostatic coating machine manufactured by Gema Co., Ltd. at a charging voltage of -60 KV to obtain a film thickness of 60 μm, and immediately baked at 200 C for 2 gin. . The resulting coating film had excellent clarity and a metallic feel.

The performance of the coating film is shown in Table 1. Example 2 A. Preparation of undercoat powder coating (thermosetting polyester containing aluminum powder) ER-6600: 75 parts, B-106
5 (hardening agent, trade name, manufactured by VEBA): nod part, 3 parts of Epicoat 1002, 1 part of Modafroni, 1 part of Shinin Green Master Color (30% pigment dispersion of Epicoat 1002), in a Henschel mixer. Dry mixing for 1 minute, then using an RCl beating type twin screw extruder manufactured by Ikegai Tekko Co., Ltd., barrel temperature: 100°C, screw temperature: 70°C.
The mixture was melt-kneaded at ℃.

The obtained pellets were finely pulverized in a hammer mill and
It was sieved through a wire mesh screen. 8 parts of high sparkle aluminum was added to 100 parts of the product that passed through the wire mesh, and dry mixing was performed again for 1 minute using a Henschel mixer, and coarse particles were sieved through a 150-mesh wire mesh to prepare an undercoat powder paint. Preparation of transparent top coat powder (thermosetting acrylic) 84 parts of Romatex PD-2310, 15 parts of decanedica, 15 parts of carboxylic acid, and 1 part of Modaflori were prepared according to the procedure in Example 1, and a transparent top coat powder was prepared. Created paint.

C. Apply the undercoating powder paint to Bonderite #1000 (product name,
Steel plate treated with iron phosphate (manufactured by Nippon Parkerizing Co., Ltd.) (4). 8×70×150Tr0fL), SNM
Painted using a plastic spray gun manufactured by France.
A semi-cured coating film having a thickness of 70 μm was obtained.

Next, a clear top coat powder was sprayed using a Sames Star Jet Gun JR-(4) type electrostatic coating machine at a charging voltage of -90 KV to obtain a film thickness of 50 μm, and immediately coated at 175°C with 13 powder. I did the baking. The resulting coating film had a metallic feel and a fleshy feel. The performance of the coating film comes first.
Shown in the table. Example 3 A: Preparation of undercoating powder paint (thermosetting acrylic containing aluminum powder) Aromatex PD-
2310: 80 parts, decanedicarboxylic acid: 14 parts, Modaflori: 5 parts, and Modaflori 1 part were dry mixed, melt-kneaded, pulverized, and sieved according to A of Example 1, and the sieved product 1 ( 15 parts of high sparkle aluminum were added to part 1), mixed again in the same manner as in Example 1, and sieved to prepare an undercoat powder paint.

Preparation of top coat clear paint (solvent type thermosetting acrylic) Bellcoat NO. llOO Clear (trade name, manufactured by NOF Corporation) was diluted with xylene to a spray viscosity and prepared.

C. Steel plate (4) treated with zinc phosphate for paint primer powder paint. 8
x 70 x 150 TIrIn) using a plastic spray gun manufactured by SNM (France) to a coating thickness of 70 μm, and baked at 180° C. for 20 minutes.

Subsequently, when the coating film temperature has fallen to room temperature, the above-mentioned clear topcoat paint is spray-painted to a dry coating thickness of 40μ, set at room temperature for 1 coat, and baked at 170°C for 2 coats. The coating was cured. The resulting coating film had a metallic feel and had good leveling properties.

The performance of the coating film is shown in Table 1. Comparative Example 1 Painting was carried out in the same manner as in Example 1, except that the paint of Example 1 was used and electrostatic spraying was performed in the same manner as the undercoat and topcoat.

The performance of the coating film is shown in Table 1. Comparative Example 2 Painting was carried out in the same manner as in Example 2, except that the paint of Example 2 was used and the undercoat was electrostatically sprayed in the same manner as the topcoat.

The performance of the coating film is shown in Table 1. Comparative Example 3 Using the paint of Example 3, coating was carried out in the same manner as in Example 3, except that the undercoat was electrostatically sprayed under the same conditions as the topcoat of Example 1 to a film thickness of 70 μm.

The performance of the coating film is shown in Table 1. From the results shown in Table 1, in Comparative Examples 1 to 3, which were electrostatically applied with an undercoat paint made by dry mixing aluminum powder with resin powder, the appearance of the paint film was poor in all cases, and the whiteness of the aluminum was abnormal and unevenness was noticeable. However, according to Examples 1 to 3 of the present invention, it is clear that there is no abnormality in the appearance of the coating film, and the finish is beautiful, and the coating film performance is also excellent.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a paint film when a metallic powder coating is electrostatically sprayed, and FIG. 2 is a cross-sectional view when the coating is similarly applied using a thermal spray gun. In Figures 1 and 2, 1 is a foil pigment, 2 is a coating film, and 3
represents the surface to be coated.

Claims (1)

[Claims] 1 After applying a thermosetting powder coating containing a foil pigment or a foil pigment and a coloring agent to the object to be coated using a thermal spraying device,
A method for applying a metallic powder coating, which is characterized in that a thermosetting transparent coating is then topcoated and cured by baking.