JP2000107680A - High-brightness coated steel sheet having excellent wear resistance, weatherability and design characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated steel sheet having excellent brightness, wear resistance and weatherability. SOLUTION: This high-brightness coated steel sheet has an upper layer coating film containing 1 to 30 wt.% pigments prepd. by coating flaky base bodies with metals and 1 to 30 wt.% organic beads. The two-layered coating films which are formed with a primer coating film on the steel sheet subjected to a chemical conversion treatment and are formed with the colored coating or transparent coating film containing. 1 to 30 wt.% high-brightness pigments formed by coating the flaky base bodies with the metals thereon or the three- layered coating films which are formed with the primer coating film, colored intermediate coating film and the transparent coating film containing the high- brightness pigments are formed on the steel sheet surface. As a result, the metallic feel free from orientability is obtained and the wear resistance of the coating films is improved by the compounding of the organic beads.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly brilliant coated steel sheet excellent in design and suitable for exterior materials, interior materials, and surface materials having a metallic feeling.

[0002]

2. Description of the Related Art As a coated steel sheet such as a pre-coated steel sheet for exterior use, an epoxy resin undercoat film containing a rust preventive pigment excellent in adhesion and corrosion resistance to a chemically treated steel sheet, a polyester resin, a fluorine resin, and the like. A multi-layer coated steel sheet on which an enamel or matte coating film based on is coated is generally used. In order to enhance the design, a metallic pigment may be blended in the top coat. As the metallic pigment, metal foil such as aluminum flake, copper flake, and stainless steel flake, mica, and plate-like iron oxide are used.

[0003] None of the conventionally used pigments have a brilliancy and weather resistance. Although the metal foil exhibits a certain degree of glitter, the glitter is inferior to the metal-coated glass flakes due to the difference in the manufacturing method. That is, since the metal foil is manufactured by machining such as a ball mill and a stamp mill, fine irregularities due to the machining remain on the foil surface and cause irregular reflection. In addition, metal foils such as aluminum flakes and copper flakes have a problem in 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 regard, glass flakes produced by cooling and solidifying from a liquid are scaly substrates having excellent luster because the surface is extremely smooth, and by utilizing this advantage, electroless Ni plating, electroless Ag plating, etc. A pigment coated with a metal has been developed (JP-A-4-359937).
JP, JP-A-5-17710, etc.).

[0004]

When a paint containing a flaky pigment is applied to the surface of a steel sheet to form a metallic coating, the flaky pigment tends to be oriented parallel to the surface of the coating. Due to this orientation, the ratio of the reflected light from the flaky pigment to the reflected light from the coating film surface is increased, and the glittering glitter does not appear. Further, when a gloss adjusting agent is added to the coating film containing the flaky pigment to deluster, the reflected light is absorbed in the coating film, and the glitter is reduced. Further, if the ends of the flaky pigment dispersed in the coating film protrude from the coating film surface, the coating film may be worn due to friction between the coating films.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been devised in order to solve such a problem, and a coating film containing a scaly pigment having excellent weather resistance and high brilliancy is formed on a steel plate. It is an object of the present invention to provide a coated steel sheet for exterior use which has a unique design with a brilliant feeling for a long period of time and has excellent wear resistance. In order to achieve the object, the highly bright coated steel sheet of the present invention has a plurality of coating layers formed on the surface of the steel sheet. It is a colored coating film containing 1 to 30% by weight of beads.

Specifically, an undercoating film is formed on a steel sheet which has been subjected to a chemical conversion treatment, and a colored coating film containing 1 to 30% by weight of a high glitter pigment obtained by coating a metal on a scaly substrate is formed thereon. The resulting two-layer coating film is obtained. A transparent coating film can be formed in place of the colored coating film.
% By weight of the highly brilliant pigment is included in the upper coating film. Furthermore,
It is also possible to form a three-layer coating film in which an undercoating film, a colored intermediate coating film, and a transparent coating film containing a highly brilliant pigment are formed on the surface of the steel sheet subjected to the chemical conversion treatment. As the high brilliant metallic pigment, glass flakes subjected to electroless Ni plating or electroless Ag plating can be used, but in order to obtain more excellent brilliancy, the average particle diameter is 10 to 300 μm and the average thickness is 0.1 μm.
A high glitter pigment is used in which a glass flake or pearl mica of 1 to 20 μm is used as a scaly substrate, and an Fe-based alloy or an Ni-based alloy having an austenite structure is sputter-coated with a film thickness of 50 to 300 °.

[0007] The upper layer coating film is blended with brilliant pigments and organic beads such as polyacrylonitrile (PAN), acrylic resin, nylon, polyolefin, and silicone resin. As the organic beads, when the thickness of the upper coating film is T, beads having a particle size R in a relationship of 1 ≦ R / T ≦ 3 are preferable, and are blended in the upper coating film in a ratio of 1 to 30% by weight. You. Further, 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]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The coating 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. Chemical treatment such as washing, surface adjustment, chromate, etc.
Apply primer paint containing rust-preventive pigment. As the undercoat paint, an epoxy resin-based resin, a polyester resin-based resin, or the like is used, but is not limited to the present invention. An average particle size of 10 to 300 μm and an average thickness of 0.1 to 2
1 to 30% by weight of 0 μm scaly high glitter pigment and PAN
A top coat containing 1 to 30% by weight of an organic resin bead is added to form an upper coat. Top coatings include
An enamel paint such as a polyester-based, fluorine-based, acrylic-based, or urethane-based paint or a polyester-based pattern-forming paint is used. As a result, a coated steel sheet having a two-layer coating film having excellent glitter and abrasion resistance can be obtained.

When a glittering pigment is blended into a top coat which is a transparent upper layer coating film, a glittering coating film can be obtained with a smaller amount of pigment added. The coating film formed on the original coating plate may have a two-layer structure or a three-layer structure. 2
In the coating film having a layer structure, an undercoat paint containing a rust-preventive pigment and a coloring pigment is applied, and then a transparent paint or a transparent pattern-forming paint containing a scaly high-brightness pigment and organic beads is applied. In a three-layer coating film, a color pigment-containing enamel paint is middle-coated on an undercoat film containing a rust-preventive pigment, and a transparent paint or a fine pattern forming paint is applied to the uppermost layer. Roll coating, spraying, curtain flow, die coating, and the like, which are used in the production of precoated steel sheets, are used for applying the paint.

The scaly substrate of the scaly high-brightness pigment to be incorporated in the topcoat paint has an average particle size of 10 to 300 μm,
Pearl mica and glass flake having an average thickness of 0.1 to 20 μm are preferred. A scaly substrate having an average particle size of less than 10 μm has a low reflected light intensity and does not exhibit sufficient glitter.
Considering the intensity of reflected light and manufacturability, the average particle size is 20 to 20.
A 0 μm scaly substrate is desirable. Although pearl mica having a thickness of 0.1 to 1 μm is commercially available as a pigment for paint, a scaly substrate thicker than commercially available pearl mica can also be used. The scaly substrate is coated with an Fe-based alloy or Ni-based alloy having an austenitic structure. The outermost layer of the coating layer of the Fe-based alloy or the Ni-based alloy is covered with a thin passivation film of several tens of atomic layers which is naturally generated by contact with air. As a result, the corrosion resistance and weather resistance are significantly improved while maintaining high gloss.

The coating of the Fe-based alloy or the Ni-based alloy is preferably applied to the scaly substrate by a powder sputtering method. In the powder sputtering method, a phenomenon in which a plurality of metal atoms constituting an alloy excited to a plasma state collide with the surface of the scaly substrate at high speed is repeated. Oxides such as SiO ₂ , Al ₂ O ₃ , and TiO ₂ constituting glass flakes and pearl mica react with the Fe-based alloy or Ni-based alloy due to the collision energy, and Fe
Compounds such as -Ti-O, Ni-Si-O, and Cr-Al-O are formed. The compound layer improves the adhesiveness of the Fe-based or Ni-based coating layer to the scaly substrate, and improves the dispersibility in the paint and the interlayer adhesion with the coating film hardening resin. In addition, the compound layer becomes a nucleus serving as a starting point of the coating layer formation,
Numerous nuclei are formed at very high densities. Therefore,
The surface of the scaly substrate is uniformly coated with a small amount of an Fe-based alloy or a Ni-based alloy, and the formed coating layer also has a dense structure without defects.

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

[0013]

The coated steel sheet of the present invention has an upper coating film in which a glitter 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, light reflected on the pigment surface is observed regardless of the observation angle, and a glittering glitter is obtained. In this regard, in a coating film containing no organic beads, the scaly substrate is easily oriented in a direction parallel to the coating film surface, and as a result, directivity is produced in the glitter. The organic beads dispersed in the upper layer coating film serve to roughen the coating film surface and promote diffuse reflection. Therefore, the amount of use of the gloss adjusting agent such as silica can be reduced, and the light reflected by the high glitter pigment due to the addition of the gloss adjusting agent is suppressed from being absorbed in the coating film. This also makes it easier to develop glittering glitter.

The organic beads also have a physical buffering effect of reducing abrasion of the coating film due to cueing of the bright pigment. In a metallic coating film without organic beads, the edge of the pigment projects from the surface of the coating film, so that when the coating films rub against each other, the coating film is scraped off at the corners of the pigment and worn. On the other hand, in the coating film according to the present invention, since the organic beads are dispersed, the organic beads come into contact preferentially when the coating films are rubbed with each other, so that the chance of contact with the pigment is 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 organic beads having a particle size R equal to or greater than the thickness T of the upper layer coating film are used. However, organic beads having a particle size of R ≧ T × 3 are not preferable because they easily fall off from the coating film and cause defects of the coating film.

[0015]

EXAMPLE 1 A hot-dip galvanized steel sheet having a thickness of 0.5 mm and a zinc adhesion amount of 120 g / m ^{2 on} one side was pickled, surface-adjusted (NPC500, manufactured by Nippon Paint), and coated chromate (NRC300NS, After being subjected to a treatment (manufactured by Nippon Paint Co., Ltd.) and drying, an epoxy undercoat containing a chromic acid-based rust-preventive pigment was applied to a dry film thickness of 5 μm. Next, a colored polyester-based paint, a colored fluorine-based paint, or a shrink paint (Neomat manufactured by Kansai Paint) was applied as a top coat. In addition, each of the overcoat paints is a high brilliant pigment in which glass flakes having an average particle diameter of 130 μm and an average thickness of 4 μm are coated with Hastelloy of a Ni-based alloy, or Hastelloy-coated pearl mica having an average particle diameter of 22 μm and an average thickness of 0.2 μm. 10% by weight and average particle size 25 μm
Was prepared by adding 10% by weight of PAN beads. The top coat is a polyester paint with a dry film thickness of 15μ.
m, dry paint film thickness 22μ
m. Specimens were collected 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 at a radius of 8 mm with the coating surface facing outward. The convex part of the bent test piece is rubbed against the surface of the same type of plate-shaped coated test piece, and the coating film is worn under the 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) up to was counted, and the wear resistance was evaluated by the number of times of wear. The number of times was evaluated as ◎ when the number was 50 or more, ○ when the number was 40 or more and less than 50, Δ when the number was 20 or more and less than 40, and × when the number was less than 20. In the glitter test, 3
Using a test piece of 00 × 200 mm and visually observing it under sunlight, those with very excellent glitter were evaluated as ◎, those with excellent glitter as ○, those with little glitter as Δ, and with glitter. A sample showing no feeling was judged as x. In the weather resistance test, a 150 × 60 mm painted test specimen was measured using a sunshine weather meter (JIS K2246).
, And sprayed with continuous ultraviolet light and sprayed with pure water for 12 minutes / 60 minutes, and the color difference ΔE and gloss retention (GR) after 1000 hours were measured.

[0017]

No. Each of the samples 1 to 6 exhibited a surface with excellent glitter. In addition, although the appearance of each coating system was different, as can be seen from the test results in Table 1, all of the coated steel sheets were excellent in wear resistance and weather resistance (Nos. 1 to 3). Further, the same effect as that of the Hastelloy-coated glass flakes was obtained even with the overcoating film to which 10% 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 (Nos. 4 to 6).

Example 2 A hot-dip galvanized steel sheet having a thickness of 0.5 mm and a zinc adhesion amount of 120 g / m ^{2 on} one side was pickled and then surface-adjusted (NPC500, manufactured by Nippon Paint).
After applying and drying a coating-type chromate (NRC300NS, manufactured by Nippon Paint Co., Ltd.), a polyester-based undercoat containing a chromic acid-based rust-preventive pigment and a coloring pigment was applied to a dry film thickness of 15 μm. Next, a polyester-based transparent paint, a fluorine-based transparent paint, or a transparent shrink paint (Neomat manufactured by Kansai Paint) was applied as an overcoat paint. Each top coat has an average particle size of 130.
High brilliant pigment in which glass flakes having a thickness of 4 μm and an average thickness of 4 μm are coated with Hastelloy of a Ni-based alloy or an average particle size of 22 μm
m, a coating containing 0.5% by weight of Hastelloy-coated pearl mica having an average thickness of 0.2 μm and 2% by weight of PAN beads having an average particle size of 25 μm was prepared. The top coat was provided so that the dry film thickness was 15 μm of a polyester paint, and the dry film thickness was 22 μm of a fluorine paint and a fine paint.

Each coated steel sheet was examined for wear resistance, brilliancy and weather resistance in the same manner as in Example 1. No. 7-12
Each of the coated steel sheets had an excellent glittering coating surface. In addition, although the appearance of each coating system was different, as can be seen from the survey results in Table 2, it was 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 as a high glitter pigment was added to the overcoat film, the same effect as that of the Hastelloy-coated glass flakes was obtained (N
o. 10-12).

[0021]

Example 3 A hot-dip galvanized steel sheet having a thickness of 0.5 mm and a zinc coating weight of 120 g / m ^{2 on} one side was pickled and then surface-adjusted (NPC500, manufactured by Nippon Paint).
After applying a coating type chromate (NRC300NS, manufactured by Nippon Paint) and drying, apply an epoxy undercoat containing a chromic acid-based rust-preventive pigment to a dry film thickness of 5 μm, and further apply a colored polyester paint or 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. Next, a polyester-based transparent paint, a fluorine-based transparent paint, or a transparent shrink paint (Neomat manufactured by Kansai Paint) was applied as an overcoat paint. Each top coat has an average particle size of 130 μm,
High brilliant pigment in which glass flakes having an average thickness of 4 μm is coated with Hastelloy of a 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 was added to which 2% by weight of PAN beads having an average particle size of 25 μm was added. The top coat was provided so that the dry film thickness was 15 μm of a polyester paint, and the dry film thickness was 22 μm of a fluorine paint and a fine paint.

Each of the coated steel sheets was examined for wear resistance, glitter and weather resistance in the same manner as in Example 1. No. 13-1
Each of the coated steel sheets of No. 8 had a coated surface with high glitter and excellent abrasion resistance. In addition, although the appearance of each coating system was different, as shown in the investigation results in Table 3, the coating system was excellent in weather resistance and also showed a small color difference ΔE (No.
13-15). Average particle size 22 μm as high brilliant pigment,
Even when 0.5% by weight of Hastelloy-coated pearl mica having an average thickness of 0.2 μm was added to the top coat, the same effect as that of Hastelloy-coated glass flakes was obtained (No.
16-18).

[0024]

COMPARATIVE EXAMPLE 1 A two-layer coating of the same color paint system as in Example 1 except that a high glitter pigment whose average particle diameter and addition amount were out of the ranges specified in the present invention was dispersed in the overcoat film. Painted steel sheet with film formed (No. 19-20), average particle size,
A coated steel sheet (N) in which a transparent top coat was formed on a colored undercoat in the same manner as in Example 2 except that a high glitter pigment whose addition amount was out of the range specified in the present invention was dispersed in the top coat.
o. 21 to 23) were prepared, and the wear resistance, brilliancy and weather resistance were similarly examined. As can be seen from the investigation results in Table 4, the average particle size of the high glitter pigment dispersed in the top coat was too small. No. 19-1, the amount of the high brilliant pigment was too small. In No. 19-2, the surface of the coating film could not obtain sufficient glitter. The average particle size is too large. 20
No.-1, in which a high glitter pigment was excessively added. In No. 20-2, the coating was hindered.

No. 21 to 23 have a three-layer coating similar to that of Example 3 when an epoxy-based primer is applied prior to the undercoating coating shown in Table 4, but in a coating structure without a primer layer, The average particle size of the high glitter pigment was smaller than 10 μm. No. 21-1 and No. 21 containing less than 0.1% of the high glitter pigment. As can be seen from 21-2, almost no glitter was exhibited, and the coating surface was poor in design. Further, the average particle size of the high glitter pigment is 300 μm.
No. exceeding In No. 22, painting was difficult regardless of the amount of addition. From these facts, No. 19-2
In No. 3, a test piece that could be used for the glitter test and the weather resistance test was not obtained. The same tendency was exhibited when a fluorine-based resin was used instead of the polyester-based resin.

[0027]

Comparative Example 2: A coated steel sheet (N
o. 24 to 29), PAN was applied to the same transparent coating film as in Example 2.
Painted steel sheets (Nos. 30 to 35) containing no beads were manufactured, and the effects of the presence or absence of PAN beads on abrasion resistance, glitter, and weather resistance were investigated. The weather resistance is not much different from the examples of the present invention as can be seen from the investigation results in Table 5, but the abrasion resistance of the coating film was extremely poor. In addition, there was a difference in the metallic feeling depending on the viewing direction. The results are shown in Examples 1 to
Compared with 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 also makes the orientation direction of the high-brightness pigment non-uniform. It can be seen that.

[0029]

[0030]

As described above, since the highly brilliant coated steel sheet of the present invention forms an upper layer coating film containing a flat brilliant pigment and organic beads, the brilliant pigment is formed by the organic beads. Is randomized, and a coating film surface having a metallic feeling without directivity is obtained. In addition, since the protrusion of the glittering pigment prevents the other coating film surface from being scraped off by the physical buffer effect of the organic beads, the abrasion resistance of the coating film is also improved. Moreover, the austenitic structure Fe
In a glitter pigment obtained by coating a flaky substrate with a base alloy or a Ni-base alloy, since a passive film is formed on the surface of the pigment, the glitter does not deteriorate even in an application that is exposed to sunlight for a long period of time. . In this way, the highly brilliant coated steel sheet of the present invention is used as a high-grade building material for exteriors, interiors, and the like, utilizing the excellent brilliancy, abrasion resistance, and weather resistance.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kumon Fumijo 7-1 Takaya Shinmachi, Ichikawa City, Chiba Prefecture Nisshin Steel R & D Co., Ltd. (72) Inventor Hiroyuki Kawanobe 7-1 Takaya Shinmachi, Ichikawa City, Chiba Prefecture Nisshin Steel Co., Ltd. Technical Research Laboratory F-term (reference) 4D075 AA01 CA32 CB15 DA06 DB05 DC03 EA07 EB16 EB35

Claims (4)

[Claims] 1. A steel sheet having a plurality of coating layers formed on the surface thereof, wherein the upper coating layer is a colored coating film containing 1 to 30% by weight of a pigment coated on a scaly substrate with a metal and 1 to 30% by weight of an organic bead. Highly brilliant coated steel sheet with excellent wear resistance, weather resistance and design. 2. A plurality of coating layers are formed on the surface of a steel sheet, and the upper coating layer is a transparent coating containing 0.1 to 5% by weight of a pigment coated on a scaly substrate with a metal and 1 to 30% by weight of an organic bead. High brilliant coated steel sheet with excellent abrasion resistance, weather resistance and design. 3. A glass flake or pearl mica having an average particle size of 10 to 300 μm and an average thickness of 0.1 to 20 μm is used as a scaly substrate, and a Fe-based alloy or an Ni-based alloy having an austenite structure is formed in a thickness of 50 to 300 °. 3. The highly brilliant coated steel sheet according to claim 1 or 2, wherein the brilliant pigment is sputter-coated and has excellent abrasion resistance, weather resistance and design. 4. The thickness T of the upper layer coating film is 1 ≦ R / T ≦ 3.
3. A highly brilliant coated steel sheet having excellent wear resistance, weather resistance and design properties according to claim 1 or 2, wherein organic beads having a particle size R having the following relationship are used.