JP3469104B2 - High brilliant painted steel sheet without directivity - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly bright coated steel sheet having excellent directivity and having no directivity, which is suitable for an exterior material, an interior material, a surface material having a metallic feeling.

[0002]

2. Description of the Related Art Painted steel sheets such as pre-coated steel sheets for exterior use are epoxy resin undercoating films containing a rust-preventive pigment excellent in adhesion and corrosion resistance on a steel sheet that has been subjected to chemical conversion treatment, polyester resin, fluorine resin, etc. A multi-layer coated steel sheet having an enamel or matte coating film based on is generally used. In order to improve the design, a metallic pigment may be added to the top coating. Metallic foils such as aluminum flakes, copper flakes, stainless steel flakes, mica, and plate-shaped iron oxide are used as the metallic pigment.

None of the conventionally used pigments have both glitter and weather resistance. The metal foil exhibits a certain degree of brilliance, but is inferior in brilliance to the metal-coated glass flakes due to the difference in the manufacturing method. That is, since the metal foil is manufactured by mechanical processing such as a ball mill and a stamp mill, fine unevenness due to the processing remains on the foil surface and causes diffuse reflection. In addition, metal foils such as aluminum flakes and copper flakes have a problem that they have poor corrosion resistance when used as exterior building materials. Metallic coated steel sheets used for exterior building materials are required to have high weather resistance in addition to design. In this respect, glass flakes produced by cooling and solidifying from a liquid are scaly substrates with excellent smoothness because their surfaces are extremely smooth. Utilizing this advantage, electroless Ni plating, electroless Ag plating, etc. A pigment coated with a metal has been developed by JP-A-4-359937.
Japanese Patent Laid-Open No. 5-17710, etc.).

[0004]

When a paint containing a scale-like pigment is applied to the surface of a steel sheet to form a metallic coating film, the scale-like pigment is easily oriented parallel to the surface of the coating film. Due to this orientation, the ratio of the reflected light from the scale-like pigment and the reflected light from the surface of the coating film increases, and the glittering sensation does not appear. Further, when a gloss adjusting agent is added to a coating film containing a scaly pigment to make the coating film matt, the reflected light is absorbed in the coating film, and the glittering feeling is lowered. Furthermore, if the ends of the scaly pigment dispersed in the coating film are projected onto the surface of the coating film, the coating film may be worn due to the friction between the coating films.

[0005]

The present invention has been devised in order to solve such a problem, and contains a scaly pigment having excellent weather resistance and high brilliance, which is randomly oriented. An object of the present invention is to provide a coated steel sheet for exterior use, in which a coating film is formed on a steel sheet, which retains a unique bright design for a long period of time and which is also excellent in wear resistance. In order to achieve the object, the non-directional high-brightness coated steel sheet of the present invention has a plurality of coating layers formed on the surface of the steel sheet, and the upper coating layer has an average particle diameter of 10 to 300 μm and an average thickness of 0. Pigment having a scale-like substrate of 1 to 20 μm coated with a metal 1 to 30% by weight
And a colored coating film containing 1 to 30% by weight of organic beads.

Specifically, an undercoat coating film is formed on a steel sheet that has been subjected to chemical conversion treatment, and a colored coating film containing 1 to 30% by weight of a high-brightness pigment in which a scale-like substrate is coated with a metal is formed thereon. To a two-layer coating film. A transparent coating film can be formed instead of the colored coating film.
A high-brightness pigment is contained in the upper coating film in an amount of wt%. Furthermore,
It is also possible to use a three-layer structure coating film in which an undercoat coating film, a colored intermediate coating film, and a transparent coating film containing a high-brightness pigment are formed on the surface of the steel sheet subjected to the chemical conversion treatment. As the high-brightness metallic pigment, glass flakes plated with electroless Ni or electroless Ag are used. Further, glass flake or pearl mica is used as a scaly substrate, and an Fe-based alloy or Ni-based alloy having an austenite structure is formed to a film thickness of 50 to 300.
Highly bright pigments sputter coated with Å are also used.

In the upper coating film, organic beads such as polyacrylonitrile (PAN), acrylic resin, nylon, polyolefin, and silicone resin are blended together with the bright pigment. As the organic beads, beads having a particle diameter R having a relationship of 1 ≦ R / T ≦ 3 are preferable, where T is the thickness of the upper coating film, and the beads are blended in the upper coating film at a ratio of 1 to 30% by weight. It Furthermore, when a fluororesin powder such as polytetrafluoroethylene (PTFE) is preferably added in an amount of 0.5 to 10% by weight, the lubricity of the coating film is improved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The coated original plate used in the present invention includes a galvanized steel plate, a zinc-aluminum alloy plated steel plate, an aluminum plated steel plate, a stainless steel plate and the like. The coated original plate is subjected to chemical treatment such as cleaning, surface adjustment, and chromate,
Apply undercoat paint containing anticorrosive pigment. As the undercoating material, an epoxy resin type, a polyester resin type, or the like is used, although it does not restrict the present invention. On the undercoat film, average particle size 10 to 300 μm, average thickness 0.1 to 2
1 to 30% by weight of scaly high-brightness pigment of 0 μm and PAN
An upper coating composition containing 1 to 30% by weight of organic resin beads such as the above is applied to form an upper coating film. For top coating,
Enamel paints such as polyester, fluorine, acrylic, urethane, etc. and polyester-based wrinkle pattern forming paints are used. As a result, a coated steel sheet having a two-layer structure coating film having excellent glitter and abrasion resistance can be obtained.

When a bright pigment is blended with a top coat which forms a transparent upper coating film, a coating film having an improved bright feeling can be obtained with a smaller amount of pigment added. The coating film formed on the coated original plate may have a two-layer structure or a three-layer structure. Two
In the case of a coating film having a layered structure, an undercoat paint containing a rust preventive pigment and a coloring pigment is applied, and then a transparent paint containing a scaly high-brightness pigment and organic beads or a transparent wrinkle pattern forming paint is applied. In the case of a three-layer coating film, an enamel paint containing a color pigment is applied as an intermediate coating on an undercoat film containing an anticorrosive pigment, and a transparent paint or a wrinkle pattern forming paint is applied to the uppermost layer. Roll coating, spraying, curtain flow, die coating, etc., which are used in the manufacture of precoated steel sheets, are adopted for the application of paint.

The scaly substrate of the scaly high-brightness pigment compounded in the overcoat paint has an average particle size of 10 to 300 μm,
Pearl mica and glass flakes having an average thickness of 0.1 to 20 μm are suitable. In the case of a scaly substrate having an average particle size of less than 10 μm, the reflected light intensity is low and a sufficient glittering feeling is not exhibited.
Considering the reflected light intensity and manufacturability, the average particle size is 20 to 20.
A 0 μm scale substrate is desirable. Pearl mica having a thickness of 0.1 to 1 μm is commercially available as a paint pigment, but a scaly substrate thicker than the commercially available pearl mica can also be used. The scaly substrate is coated with a Fe-based alloy or a Ni-based alloy having an austenite structure. The Fe-based alloy or Ni-based alloy coating layer has the outermost layer covered with a thin passivation film of several tens of atomic layers that naturally occurs upon contact with air. As a result, corrosion resistance and weather resistance are remarkably improved while maintaining high gloss.

The Fe-based alloy or Ni-based alloy coating is preferably applied to the scaly substrate by the powder sputtering method. In the powder sputtering method, a phenomenon in which a plurality of metal atoms forming an alloy excited to a plasma state collide with the surface of the scaly substrate at high speed is repeated. Due to this collision energy, oxides such as SiO ₂ , Al ₂ O ₃ , and TiO ₂ that compose glass flakes and pearl mica react with the Fe-based alloy or the Ni-based alloy, and Fe-T is formed at the interface.
Compounds such as i-O, Ni-Si-O, Cr-Al-O are formed. The compound layer improves the adhesion of the Fe-based or Ni-based coating layer to the scaly substrate, and improves the dispersibility in the coating material and the interlayer adhesion with the coating film-constituting resin. Further, the compound layer serves as nuclei that act as a starting point for forming the coating layer, and a large number of nuclei are formed at an extremely high density. Therefore, the surface of the scaly substrate is uniformly coated with a small amount of Fe-based alloy or Ni-based alloy, and the formed coating layer also has a defect-free and dense structure.

The Fe-based or Ni-based coating layer formed on the surface of the scaly substrate is, if necessary, a chromic acid-based, phosphoric-acid-based,
The surface treatment is performed using an inorganic surface treatment agent such as an alumina-based or zirconia sol-based agent, various silane coupling agents, and a titanate coupling agent. By this surface treatment, F
The dispersibility of the e-based or Ni-based coating layer with respect to the resin constituting the coating film and the interlayer adhesion are improved.

[0013]

The coated steel sheet of the present invention has an upper coating film in which a bright pigment and organic beads are dispersed. Organic beads
It acts as a steric hindrance in the upper coating film and randomizes the orientation direction of the scaly bright pigment. That is, since the surface of the scaly substrate is oriented in multiple directions, the light reflected by the pigment surface is observed regardless of the observation angle, and a glittering feeling is obtained. In this respect, in a coating film containing no organic beads, the scaly substrate is likely to be oriented in a direction parallel to the surface of the coating film, and as a result, the glitter feeling is directional. The organic beads dispersed in the upper coating film have a function of roughening the coating film surface and promoting irregular reflection. Therefore, the amount of the gloss adjusting agent such as silica used can be reduced, and absorption of light reflected by the high-brightness pigment due to the addition of the gloss adjusting agent in the coating film is suppressed. This also makes it easier to produce a glittering feeling.

The organic beads also have a physical buffering effect of reducing the abrasion of the coating film due to the cueing of the high-brightness pigment. In a metallic coating film without organic beads, the end portions of the pigment project from the coating film surface, so that when the coating films rub against each other, the coating film is scraped by the corners of the pigment and abraded. On the other hand, in the coating film according to the present invention, since the organic beads are dispersed, the organic beads are preferentially contacted with each other when the coating films are rubbed with each other, and the chances of contact of the pigment are reduced. Therefore, the coating film surface is not scraped by the protrusions of the pigment, and the abrasion resistance is improved. Such a physical buffering effect becomes remarkable when using organic beads having a particle size R which is equal to or larger than the thickness T of the upper coating film. However, organic beads having a particle size of R ≧ T × 3 are not preferable because they easily fall off the coating film and cause defects in the coating film.

[0015]

Examples Example 1: Hot-dip galvanized steel sheet having a plate thickness of 0.5 mm and a zinc deposition amount on one side of 120 g / m ^{2 on} one side was subjected to surface conditioning (NPC500, made by Nippon Paint), coating type chromate (NRC300NS, After being subjected to a treatment (made by Nippon Paint Co., Ltd.) and dried, an epoxy-based undercoat paint containing a chromic acid-based rust preventive pigment was applied so that the dry coating film thickness would be 5 μm. Next, a colored polyester-based paint, a colored fluorine-based paint or a Chijimi paint (Kansai Paint Neomat) was applied as a top coat paint. In each top coat, a high-brightness pigment obtained by coating glass flakes having an average particle size of 130 μm and an average thickness of 4 μm with a Hastelloy Ni-based alloy, or a Hastelloy-coated pearl mica having an average particle size of 22 μm and an average thickness of 0.2 μm. 10% by weight and average particle size 25 μm
A paint containing 10% by weight of PAN beads was prepared. The top coat is a polyester-based paint with a dry film thickness of 15μ.
m, Fluorine-based paint and Chijimi-based paint with a dry film thickness of 22μ
It was provided so as to be m. Test pieces were taken from each coated steel sheet and subjected to a wear resistance test, a glitter test and a weather resistance test.

In the abrasion resistance test, a test piece having a width of 65 mm and a length of 100 mm was bent with a radius of 8 mm with the coating surface facing outward. The convex portion of the bent test piece is rubbed against the surface of the same type of flat-plate coated test piece, and the coating film is abraded and the base is exposed under the abrasion conditions of a sliding distance of 70 mm, a load of 5 kg and a speed of 300 mm / min. The number of times of friction (reciprocation) was counted, and the abrasion resistance was evaluated by the number of times of abrasion. The number of times was determined to be 50 or more, ◯, 40 to less than 50, O, 20 to less than 40, and less than 20 to x. 3 in the glitter test
Using a 00 x 200 mm test piece, visually observing it under sunlight, the one with a very excellent glittering feeling is ◎, the one with a excellent glittering feeling is ○, the one with little glittering feeling is △, a glittering feeling The case where no feeling was seen was judged as x. In the weather resistance test, a 150 x 60 mm coating test piece was used as a sunshine weather meter (JIS K2246).
And continuous ultraviolet irradiation and pure water spraying for 12 minutes / 60 minutes were performed, and the color difference ΔE and gloss retention rate (GR) after 1000 hours were measured.

[0017]

No. In each of 1 to 6, a surface having an excellent glittering feeling was exhibited. In addition, although the appearance of each coating system was different, as shown in the test results of Table 1, all the coated steel sheets were excellent in wear resistance and weather resistance (Nos. 1 to 3). Further, the same effect as Hastelloy-coated glass flakes was obtained even with the top coat film containing 10% by weight of Hastelloy-coated pearl mica having an average particle size of 22 μm and an average thickness of 0.2 μm (Nos. 4 to 6).

Example 2 After pickling a hot-dip galvanized steel sheet having a plate thickness of 0.5 mm and an amount of zinc deposited on one side of 120 g / m ^{2 on} one side, surface adjustment (NPC500, manufactured by Nippon Paint),
After applying a coating type chromate (NRC300NS, manufactured by Nippon Paint Co., Ltd.) and drying, a polyester-based colored undercoat paint containing a chromic acid-based anticorrosive pigment and a coloring pigment was applied so as to have a dry coating film thickness of 15 μm. Then, a polyester transparent paint, a fluorine-based transparent paint or a transparent shredded paint (Neomat manufactured by Kansai Paint) was applied as a top coat paint. In addition, the average particle size of each top coat is 130
High-brightness pigment in which glass flakes having an average thickness of 4 μm and an average thickness of 4 μm are coated with a Ni-based alloy Hastelloy, or an average particle size of 22 μ
m, 0.5 wt% of Hastelloy-coated pearl mica having an average thickness of 0.2 μm, and 2 wt% of PAN beads having an average particle size of 25 μm were prepared. The top coating film was formed by using a polyester-based paint so as to have a dry film thickness of 15 μm, and a fluorine-based paint and a shredded paint so as to have a dry film thickness of 22 μm.

With respect to each coated steel sheet, abrasion resistance, glitter and weather resistance were investigated in the same manner as in Example 1. No. 7-12
Each of the coated steel sheets had a coated surface with an excellent luster. Further, although the respective coating systems have different appearances, as shown in the examination results in Table 2, they were excellent in wear resistance and weather resistance (Nos. 7 to 9). Even if 0.5% by weight of Hastelloy-coated pearl mica having an average particle size of 22 μm and an average thickness of 0.2 μm was added to the top coat as a high-brightness pigment, the same effect as Hastelloy-coated glass flakes was obtained (N
o. 10-12).

[0021]

Example 3: After pickling a hot-dip galvanized steel sheet having a plate thickness of 0.5 mm and an amount of zinc deposited on one side of 120 g / m ^{2 on} one side, surface adjustment (NPC500, made by Nippon Paint),
After applying a coating type chromate (NRC300NS, manufactured by Nippon Paint Co., Ltd.) and drying, an epoxy undercoat paint containing a chromic acid anticorrosive pigment is applied so that the dry film thickness becomes 5 μm, and a colored polyester paint or An intermediate coating was performed using a colored fluorine-based paint. The intermediate coating film was set to a dry film thickness of 10 μm with a colored polyester paint and a dry film thickness of 12 μm with a colored fluorine-based paint. Then, a polyester transparent paint, a fluorine-based transparent paint or a transparent shredded paint (Neomat manufactured by Kansai Paint) was applied as a top coat paint. In addition, each top coat has an average particle size of 130 μm,
High-brightness pigment obtained by coating glass flakes having an average thickness of 4 μm with Hastelloy of Ni-based alloy or Hastelloy-coated pearl mica 0.5 having an average particle size of 22 μm and an average thickness of 0.2 μm
A coating material containing 2% by weight and 2% by weight of PAN beads having an average particle size of 25 μm was prepared. The top coating film was formed by using a polyester-based paint so as to have a dry film thickness of 15 μm, and a fluorine-based paint and a shredded paint so as to have a dry film thickness of 22 μm.

With respect to each coated steel sheet, abrasion resistance, glitter and weather resistance were investigated in the same manner as in Example 1. No. 13-1
Each of the coated steel sheets of No. 8 had a coating surface having a high glittering feeling and excellent wear resistance. Further, although the respective coating systems have different appearances, as shown in the survey results in Table 3, they have excellent weather resistance and a small color difference ΔE (No.
13-15). Average particle size of 22 μm as a high luster pigment,
Even when Hastelloy-coated pearl mica having an average thickness of 0.2 μm was added to the top coating film in an amount of 0.5% by weight, the same effect as that of Hastelloy-coated glass flakes was obtained (No.
16-18).

[0024]

Comparative Example 1: A two-layer structure coating of a colored coating system similar to that of Example 1 except that a high-brightness pigment having an average particle diameter and an addition amount outside the ranges specified in the present invention was dispersed in the top coating film. Coated steel sheet (No. 19 to 20) with a film, average particle size,
A coated steel sheet in which a transparent topcoat film was formed on a colored undercoat film similar to that of Example 2 except that a high-brightness pigment whose addition amount was outside the range specified in the present invention was dispersed in the topcoat film (N
o. Nos. 21 to 23) were produced, and abrasion resistance, glitter and weather resistance were similarly investigated. As can be seen from the survey results in Table 4, the average particle size of the high-brightness pigment dispersed in the overcoat film was too small. 19-1, too small amount of high-brightness pigment added No. 19-1. In No. 19-2, it was a coating film surface which cannot obtain sufficient glitter. The average particle size is too large. 20
-1, No. 1 in which the high-brightness pigment was excessively added. In 20-2, there was a problem in painting.

No. Nos. 21 to 23 are coating films having a three-layer structure similar to Example 3 when an epoxy-based primer is applied prior to the undercoat coating film shown in Table 4, but in the coating film structure without a primer layer, The average particle size of the high-brightness pigment is less than 10 μm. No. 21-1 and the addition amount of the high-brightness pigment are less than 0.1%. As shown in No. 21-2, almost no glitter was exhibited, and the coating surface was inferior in design. The average particle size of the high-brightness pigment is 300 μm.
No. In No. 22, coating was difficult regardless of the amount of addition. From this, No. 19-2
In No. 3, no test piece that could be used for the glitter test and the weather resistance test was obtained. Further, even when a fluorine-based resin was used as the base resin instead of the polyester-based resin, the same tendency was shown.

[0027]

COMPARATIVE EXAMPLE 2 A coated steel sheet having a two-layer coating film of the same coloring paint system as in Example 1 but containing no PAN beads (N
o. 24 to 29), and PAN on the same transparent coating film as in Example 2.
Painted steel sheets (No. 30 to 35) containing no beads were manufactured, and the effects of the presence or absence of PAN beads on the wear resistance, glitter, and weather resistance were investigated. Regarding the weather resistance, although there is not much difference from the examples of the present invention as seen in the examination results in Table 5, the abrasion resistance of the coating film was extremely poor. Further, there was a difference in metallic feeling depending on the viewing direction. The results are shown in Examples 1 to 1.
When compared to 3, the high-brightness pigment prevents scratches on the surface of the coating film due to the physical buffering effect of the PAN beads dispersed in the coating film, and the orientation direction of the high-brightness pigment is made nonuniform. It is revealed.

[0029]

[0030]

As described above, the high-brilliance coated steel sheet of the present invention forms the upper coating film containing the flat bright pigment and the organic beads, and therefore the bright pigment is formed by the organic beads. The orientation direction of is randomized, and a coating film surface having a metallic feeling without directivity is obtained. Further, abrasion of the coating film is improved because the physical buffering effect of the organic beads prevents the protrusion of the bright pigment from scraping off the surface of the other coating film. Moreover, Fe having an austenite structure
In the bright pigment in which the base alloy or the Ni-based alloy is coated on the scale-like substrate, since the passivation film is formed on the surface of the pigment, the glitter does not deteriorate even in the application of long-term exposure to sunlight. . In this way, the highly bright coated steel sheet of the present invention is used as a high-grade building material for exteriors, interiors, etc. by utilizing its excellent glitter, abrasion resistance and weather resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Kawanobe 7-1 Takatani Shinmachi, Ichikawa City, Chiba Nisshin Steel Co., Ltd. Technical Research Laboratory (56) Reference Japanese Patent Laid-Open No. 4-11672 (JP, A) Kaihei 10-259316 (JP, A) JP-A-5-1248 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B05D 1/00-7/26 B32B 15/08

Claims (4)

(57) [Claims] 1. A plurality of coating layers are formed on the surface of a steel sheet, and the upper coating layer has an average particle diameter of 10 to 300 μm and an average thickness.
A non- oriented high-brightness coated steel sheet which is a colored coating film containing 1 to 30% by weight of a pigment having a scale-like substrate of 0.1 to 20 μm coated with a metal and 1 to 30% by weight of organic beads. 2. A plurality of coating layers are formed on the surface of a steel sheet, and the upper coating layer has an average particle diameter of 10 to 300 μm and an average thickness.
Pigment of 0.1 to 20 μm scale coated with metal 0.1 to 5% by weight and organic beads 1 to 30% by weight
A highly bright coated steel sheet with no directivity that is a transparent coating film containing 3. A high-brightness pigment comprising glass flakes or pearl mica as a scaly substrate, and a sputter-coated Fe-based alloy or Ni-based alloy having an austenite structure with a film thickness of 50 to 300 Å is used. Fingers
Highly bright coated steel sheet with no tropism . 4. The thickness T of the upper coating film is 1 ≦ R / T ≦ 3.
3. A highly bright coated steel sheet having no directivity according to claim 1 or 2, wherein organic beads having a particle size R satisfying the relationship are used.