JP2883507B2 - Painted metal body and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly used for road-related products such as tunnel interior boards, bridge fences, road fences, sign posts, etc., and interior and exterior of buildings, and is used for corrosion resistance, weather resistance, and pollution resistance. The present invention relates to an excellent coated metal body and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, tunnel interior boards, bridge protective fences,
Methods for manufacturing painted metal bodies used for road-related products such as road fences and sign posts and interior and exterior of buildings include a method of applying a liquid paint such as an acrylic resin or a urethane resin to a metal body, and a method of applying an epoxy resin. There is a method of powder-coating a powder coating such as resin, acrylic resin, and polyester.

[0003]

However, in the former manufacturing method of applying a liquid paint as described above, the coating film formed on the metal body has excellent surface smoothness, but the coating is performed once. In order to improve the corrosion resistance, it was necessary to repeatedly apply the coating to increase the thickness of the coating, and the coating took a long time. Further, in the liquid paint, pinholes are easily formed in the coating film due to a solvent or the like in the paint, and when the pinholes are formed, corrosion is easily generated therefrom. Further, the liquid paints of acrylic resins and urethane resins generally used were inferior in weather resistance and stain resistance.

In the latter method of powder coating a powder coating, since the powder coating is used, the thickness of the coating film formed on the metal body by one coating is large, and the coating of the liquid coating is difficult. The coating time is shortened because it is not necessary to repeatedly apply as many times. Further, since no solvent or the like was used in the paint, no pinholes or the like were generated and the corrosion resistance was excellent. However, the coating film formed by the powder coating had poor surface smoothness as if it had a wavy appearance, and was not satisfactory in terms of weather resistance and stain resistance.

[0005] The present invention solves the above-mentioned problems of the conventional method of manufacturing a coated metal body, and provides corrosion resistance and weather resistance,
An object of the present invention is to provide a coated metal body having excellent stain resistance and a method for producing the same.

[0006]

In order to achieve the above object, the present invention has the following arrangement. That is, in the coated metal body according to the present invention, a resin coating film of a powder coating is formed on the metal body, and a silicone compound is used as a main component on the resin coating film , which contains a coloring pigment or ultrafine metal particles . The method of manufacturing a coated metal body according to the present invention is characterized in that a resin coating film by powder coating is applied to the metal body under normal baking conditions. Slightly
Formed by baking low , and forming a coating layer containing a silicone compound as a main component on the resin coating film at a temperature equal to or higher than the baking temperature of the resin coating film.
It is characterized by being formed by baking under high temperature conditions .

Hereinafter, the configuration of the present invention will be described in more detail.

As the metal body used in the present invention, generally, steel, aluminum, copper, zinc, other metals and alloys thereof are suitably used, and stainless steel, galvanized steel, and aluminum having excellent corrosion resistance are used. Etc. are particularly preferably used. Also, the shape of the metal body may be any shape such as a flat plate, a curved plate, a corrugated plate, or a column such as a prism or a cylinder. It may have an irregular cross section.

The surface of the metal body is subjected to a degreasing process in advance to remove dirt and oil in order to improve the adhesion to the paint, and the surface is roughened by sand blasting or the like together with the degreasing process, A phosphate film such as a phosphate film may be formed by the treatment, or a known primer layer may be further formed.

[0010] The powder coating for forming a resin coating on the metal body is a coating method for forming a resin coating by heating and melting a powder coating made of a synthetic resin on the surface of the metal body. An appropriate coating method such as thermal spraying, electrostatic coating or the like is used.
The powder coating is not particularly limited, but generally a powder coating of an epoxy resin, an acrylic resin, polyester, or the like is suitably used. The baking conditions for the resin coating vary depending on the type and thickness of the resin used.Generally, the resin coating is heated again when forming a coating layer mainly composed of a silicone compound on the resin coating. 150-170 which is slightly lower than the normal baking temperature
C. and a heating time of 10 to 30 minutes.

The thickness of the formed resin coating film is not particularly limited, but is generally preferably 20 to 200 μm. That is, the thickness is within the range of a thickness that can be obtained by a single electrostatic powder coating or the like, and when the thickness is 20 μm or less, the concealing power of the resin is inferior. This is because unevenness appears remarkably. However, the thickness of the resin coating film may be further increased by suppressing the occurrence of surface irregularities by performing the coating twice or more.

The coating layer formed on the resin coating film has a silicone compound as a main component, and is formed by applying a paint containing a silicone compound as a main component. As the silicone compound, generally an organic silicon compound as a main chain a white hexane bond such as silicone resins are alone or organosilicon compound and an alkyd, epoxy, acrylic, polyester, phenolic, melamine, and modified organic material such as urethane are such ones preferably used in the silicone-modified sol obtained by the reaction, the paint is a shrink with type, it is used as it can shorten the curing time by heat curing, preferably epoxy-modified silicone sol, polyester A modified silicone sol or an acrylic-modified silicone sol is used. It is also preferable that the content of the modified organic substance is lower than that of the organic silicon polymer, because it is excellent in weather resistance and adhesion and the amount of gas generated during combustion is reduced. In addition, the paint containing the silicone compound as a main component may deteriorate the resin film over time.
It is necessary Rukoto be colored to prevent.

In order to form a coating layer containing the above-mentioned silicone compound as a main component on a resin coating film, a pigment, an anti-settling agent, an ultraviolet absorber and ultrafine metal particles (zinc oxide, titanium oxide, A modifier such as iron) and a solvent may be mixed into a paint, and the paint may be applied on a resin coating film and cured . Baked with conditions it is generally baking temperature 1
60 to 200 ° C., Ru is the heating time 15 to 30 minutes. The thickness of the formed coating layer is not particularly limited, but is generally about 5 to 50 μm. In addition, in order to apply the paint on the resin coating, spray coating, brush coating,
A known method such as roller coating is applied. An adhesive such as an adhesive may be interposed between the resin coating film and the coating layer.

[0014]

The coated metal body and the method of manufacturing the same according to the present invention first form a resin coating by powder coating on the metal body, thereby forming a thick resin coating in a single coating to reduce the coating time. In addition to shortening, the occurrence of pinholes and the like is eliminated, and the corrosion resistance of the resulting coated metal body is improved. In addition, by forming a coating layer containing a silicone compound as a main component on the resin coating film, the surface smoothness is improved,
Corrosion resistance, weather resistance and stain resistance are improved by the excellent water repellency, chemical resistance and the like of the silicone compound. In particular, in the coated metal body of the present invention,
Silicone compounds contain color pigments or ultrafine metal particles
Light transmitted through the coating layer is reduced as much as possible.
To prevent aging of the underlying resin coating.
Is possible, and coating due to aging of the resin coating
Delamination from the layer can be prevented for a long period of time. or
In the manufacturing method, the baking conditions of the resin coating film are exceeded.
It is 1 more than the baking condition of normal powder paint to avoid baking.
Since the temperature was reduced to 50-170 ° C, the reactive coating
(Functional group) is left.
Baking at 60-200 ° C, baking the resin coating again
Or baking at higher temperature conditions, unreacted
The base undergoes a curing reaction when the coating layer is baked, so that both upper and lower
Strong adhesion of the layer is obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. FIG. 1 is an explanatory sectional view showing one embodiment of a coated metal body obtained by the method for producing a coated metal body of the present invention.

First, as shown in FIG. 1, a hot-dip galvanized steel sheet is used as a metal body 1, the surface of the hot-dip galvanized steel sheet is subjected to degreasing and chemical conversion treatment, and then a polyester powder paint is electrostatically powder-coated, and a temperature of 170 ° C. And baked for 20 minutes to form a resin coating film 2 having a thickness of 50 μm. Next, a liquid paint (solid content: 20%) containing a silicone-modified sol of the same color as the powder paint as a main component is spray-coated on the resin coating film 2,
Baking for 20 minutes to form a coating layer 3 having a thickness of 10 μm,
A coated metal body according to Example 1 of the present invention was obtained.

As the metal body 1, a stainless steel plate (SU)
S304) to degrease the surface of the stainless steel plate.
After washing with water, epoxy powder coating is applied with electrostatic powder coating, and
By baking at 0 ° C. for 20 minutes, a resin coating film 2 having a thickness of 70 μm was formed. Next, a transparent liquid paint (solid content: 30%) containing an ultraviolet absorbent and ultrafine metal particles (zinc oxide, titanium oxide, iron oxide, etc.) and containing a silicone-modified sol as a main component is spray-coated on the resin coating film 2. The coating was baked at 180 ° C. for 20 minutes to form a coating layer 3 having a thickness of 19 μm, thereby obtaining a coated metal body according to Example 2 of the present invention.

Further, an aluminum plate was used as the metal body 1, the surface of the aluminum plate was degreased and washed with water, and then a polyester powder coating was electrostatically coated with a powder of 160 ° C and 20 ° C.
After baking for a minute, a resin coating film 2 having a thickness of 100 μm was formed. Next, a brown liquid paint (solid content: 20%) containing silicone-modified sol as a main component is spray-coated on the resin coating film 2 and baked at 160 ° C. for 20 minutes to form a coating layer 3 having a thickness of 15 μm. A coated metal body according to Inventive Example 3 was obtained.

Next, as Comparative Example 1, after the surface of a hot-dip galvanized steel sheet was degreased and chemically treated, a polyester powder coating was electrostatically coated and baked at 190 ° C. for 20 minutes to form a resin coating having a thickness of 50 μm. Was obtained.

As Comparative Example 2, a stainless steel plate (S
After the surface of US304) was degreased and washed with water, an epoxy powder coating was applied by electrostatic powder coating and baked at 180 ° C. for 20 minutes to obtain a coated metal body having a resin coating film having a thickness of 70 μm.

Next, with respect to the coated metal bodies according to Examples 1 to 3 and Comparative Examples 1 and 2, a salt spray test was conducted to examine corrosion resistance, a sunshine weatherometer test, a stain resistance test, and a surface test were conducted to examine weather resistance. Was examined for smoothness, and the results are shown in Table 1.

[0022]

[Table 1]

The salt spray test conforms to JIS-K-5400
According to the prescribed method, two diagonal lines intersecting with each other by a cut that penetrates the resin coating of the test piece with a sharp blade and reaches the surface of the metal body, and draws the test piece in a test chamber where salt water mist is generated. In a water spray test to evaluate the adhesion between the resin coating and the metal body by examining the size of the blisters formed in the resin coating and the coating layer for 1000 hours. No outbreak was observed.

The sunshine weatherometer test is described in J.
According to the method specified in IS-K-5400, 1000
Observation of the state of deterioration of the surface after irradiation for a period of time shows that in Table 1, 劣化 indicates that no deterioration was observed, and X indicates that deterioration and choking occurred.

The stain resistance test conforms to JIS-K-5400.
Using the specified method , stain the painted surface of the test piece with an oil-based marking pen, wipe it off after leaving it for the specified time, visually check the degree of contamination on the painted surface, ◎ indicates that the stain has disappeared, and × indicates that the stain has not disappeared. It shows that it remains. The surface smoothness was visually inspected. A indicates that the surface was smooth, and X indicates that the surface was wavy.

As shown in Table 1, the coated metal bodies according to Examples 1 to 3 of the present invention were found to be superior in corrosion resistance, weather resistance and stain resistance as compared with Comparative Examples 1 and 2.

Next, the metal body and resin coating shown in Table 2 were applied.
Combination of film and coating layer, film thickness, coating color, manufacturing conditions
In this case, a painted metal body according to Examples 4 to 10 of the present invention was prepared.
Then, for Examples 4 to 10, the same conditions as described above were used.
The salt spray test to check corrosion resistance and weather resistance
Sunshine weatherometer test, contamination resistance
And the surface smoothness were examined.
3 is shown.

[0028]

[Table 2]

[0029]

[Table 3]

As is clear from Table 3, the metal body is
Stainless steel, galvanized steel, or aluminum
Resin coatings, epoxy powder coatings, acrylic powders
Paint or polyester powder paint,
The covering layer is made of epoxy-modified silicone sol or polyester
Silicone sol or acrylic-modified silicone sol
The coated metal bodies according to Examples 4 to 10 of the present invention
It turns out that it is excellent in corrosion resistance, weather resistance, and stain resistance.

[0031]

As described in detail above, the coated metal body of the present invention and
And a method of manufacturing the same, since a resin coating is formed on a metal body by powder coating, a single coating can form a thick resin coating, thereby shortening the coating time and forming the resin coating. Since the resin coating film does not have pinholes and the like as compared with a conventional coating film made of a liquid paint, the resulting coated metal body is extremely excellent in corrosion resistance.

Further, in the coated metal body of the present invention and the method for producing the same, since the coating layer containing a silicone compound as a main component is formed on the resin coating film, compared with the conventional one consisting only of powder coating. , With excellent surface smoothness,
It has excellent corrosion resistance, weather resistance and stain resistance due to the excellent water repellency and chemical resistance of the silicone compound. On the other hand, in the coated metal body of the present invention, the coating
Contains color pigments or ultrafine metal particles in the silicone compound
The resin coating is exposed to ultraviolet light by the coating layer.
Aging deterioration is reduced, delamination of both layers due to aging
Is prevented for a long time. In the production method of the present invention,
Will not overbake the baking conditions of the resin coating
150 to 170 ° C, slightly lower than normal baking temperature
Therefore, the resin coating will be in a semi-cured state and unreacted groups will remain
ゝOn the other hand, the upper coating layer has a temperature of 160 to 200 ° C.
Or heated at a higher temperature
As a result, unreacted groups in the resin coating undergo a curing reaction during baking of the coating layer
In other words, a strong adhesion between the upper and lower layers can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing one embodiment of a coated metal body obtained by a method for manufacturing a coated metal body of the present invention.

[Explanation of symbols]

 1 metal body 2 resin coating 3 coating layer

Continuation of the front page (56) References JP-A-4-318088 (JP, A) JP-A-63-143976 (JP, A) JP-A-4-28540 (JP, A) JP-A 64-38178 (JP , A) "Silicone Handbook," Nikkan Kogyo Shimbun, August 31, 1990, Chapter 13, Modified Silicone Resin (P.492-514)

Claims (4)

(57) [Claims] A resin coating of a thermosetting powder coating is formed on a metal body, and one or more silicone compounds of an epoxy-modified silicone sol, a polyester-modified silicone sol or an acrylic-modified silicone sol are formed on the resin coating. A coated metal body having a coating layer containing a coloring pigment or ultrafine metal particles as a main component. 2. The metal body is made of stainless steel, galvanized steel,
2. The coated metal body according to claim 1, comprising aluminum. 3. The resin coating film according to claim 1, wherein said resin coating film comprises an epoxy powder coating, an acrylic powder coating or a polyester powder coating.
Or the coated metal body according to 2. 4. A resin coating is formed by applying a thermosetting powder coating to a metal body and baking at 150 to 170 ° C. slightly lower than a normal baking temperature to form an epoxy-modified silicone sol on the resin coating. Equivalent to a baking temperature of 160 to 200 ° C by applying a coating containing a color pigment or ultrafine metal particles to one or more silicone compounds of a polyester-modified silicone sol or an acrylic-modified silicone sol as a main component. A method for producing a coated metal body, comprising completely curing the resin coating under the above high temperature conditions and forming a coating layer firmly adhered to the resin coating.