JP2010240944A - Coated metal sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated metal sheet which can be colored as optionally decided as a roofing material and does not cause a working person on the roof to slip during a roofing operation, with superior snow sliding property on the roof during a wintertime. <P>SOLUTION: This coated metal sheet is made up of an organic coating layer with a glass transition temperature of 10 to 60°C, and contains 3 to 30 mass% of boron nitride powder with an average particle diameter of 0.01 to 10 μm, 0.5 to 10 mass% of silica powder with an average particle diameter of 0.05 to 5 μm, and 0.1 to 10 mass% of fluororesin microparticle with an average particle diameter of 0.01 to 10 μm. In addition, the organic coating layer is applied to the outdoor surface of the metal sheet, and also, the organic coating layer containing the boron nitride and more than one kind of carbon black may be formed on the indoor side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coated metal plate excellent in human slip resistance, snow sliding properties, design properties and the like during construction of a roof. More specifically, it is easy to color as a painted metal plate, it is difficult to slip even if an operator gets on it as a roofing material, it can be done safely, and if snow accumulates in winter, it will snow. The present invention relates to a so-called painted metal plate that is easy to slide down and has excellent human slip resistance and snow slide resistance.

  Painted metal plates having a colored organic coating layer on the surface are widely used as roofing materials mainly in Hokkaido and Tohoku. The performance required as a roofing material in Hokkaido and Tohoku is the appearance design, ease of construction, and snow sliding.

  In order to improve snow sliding performance, a method is known in which a fluorine resin such as vinylidene fluoride is applied to the organic coating layer of the coated metal plate, and a fluorine resin powder is added as a lubricant. For example, in Patent Document 1, a vinylidene fluoride resin is used for an organic coating layer, a fluororesin powder, polyacrylonitrile beads, a ceramic aggregate having a specified size are added, and combined with an undercoat organic coating layer, snow-sliding properties A technique for improving the above has been proposed. Certainly, this method improves snow sliding performance, but there is a problem that an operator who runs the roof is slippery.

  Patent Document 2 discloses that an organic coating layer contains 0.1 to 5% by mass of fluororesin particles having an average particle size of 10 μm or less as an invention that achieves both human slip resistance and snow sliding properties, and the organic coating layer. Proposed a colored metal plate characterized in that the surface has a surface roughness with a maximum surface roughness (Rmax) of 15 μm or more and a number of surface roughness peaks of 5 μm or more present per 10 mm of 10 or more. Has been. Certainly, this method improves the human slip resistance and snow sliding performance, but since the snow sliding performance is controlled by the manifestation of hydrophobicity of the fluororesin, there is a limit to the provision of snow sliding performance from hydrophobicity. The performance was insufficient.

  In the patent document 3, the present inventor has 3 to 60% by mass of carbon black and 0.5 to 5% by mass of silica powder having an average particle size of 5 μm or less, and an average particle size of 3% by mass. Painted metal plate with 0.05 to 5% by mass of fluororesin particles of 10 μm or less, coated with a paint that has a glass transition temperature of 10 to 50 ° C. of the organic coating layer after painting, is resistant to slip and snow. It states that it is excellent in performance. Certainly, this method improves the anti-slip and snow-sliding properties, but the organic coating layer turns black due to the essential inclusion of carbon black, and any commonly used pigments or dyes are used. However, there is a problem that it is difficult to control the color of the roof to an arbitrary color.

  In other words, as a roofing material, there is a coated metal plate that is highly compatible with human slip resistance, which makes it difficult for workers to slip during construction, and snow sliding performance that easily slides even when snow accumulates on the roof in winter. It was desired.

JP 2000-355671 A JP-A-9-277435 JP 2004-210974 A

  As described above, various types of painted metal sheets for roofs have been proposed so far, but a painted metal sheet that is highly compatible with human slip resistance and snow sliding properties and can be colored in any color is still available. Not proposed.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a coated metal plate excellent in human slip resistance, snow sliding performance and design.

  The present invention solves the above-mentioned problems, and the gist thereof is as follows.

(1) As the outermost layer on one side of the metal plate, 3 to 30% by mass of boron nitride having an average particle size of 0.01 to 10 μm, 0.5 to 10% by mass of silica powder having an average particle size of 0.05 to 5 μm, It has a first organic coating layer containing 0.1 to 10% by mass of fluororesin fine particles having an average particle size of 0.01 to 10 μm in a thickness of 10 to 50 μm, and the glass transition temperature of the organic coating layer is 10 to 10 μm. A painted metal plate characterized by being 60 ° C.
(2) A second organic coating layer containing 3 to 30% by mass of at least one of boron nitride and carbon black on the opposite surface of the metal plate on which the first organic coating layer is formed. The coated metal plate according to (1), having a thickness of 5 μm or more.
(3) The coated metal plate according to (1) or (2), wherein the metal plate is a plated steel plate.

  As described above, the coated metal plate of the present invention exhibits better anti-slip resistance during construction and winter snow-sliding properties than conventional coated metal plates, and can be colored in any color. It is suitable as a painted metal plate for roofs in snowy areas.

The present invention is described in further detail below.
In order to solve the above-mentioned problems and to develop a coated metal plate having excellent human slip resistance and snow sliding properties, the present inventor has developed the physical properties of the organic coating layer of the painted metal plate, the human slip resistance and the snow sliding performance. The relationship was examined in detail. As a result, as the outermost layer on one side of the metal plate, 3 to 30% by mass of boron nitride having an average particle size of 0.01 to 10 μm, 0.5 to 10% by mass of silica powder having an average particle size of 0.05 to 5 μm, A coated metal plate having a first organic coating layer containing 0.1 to 10% by mass of fluororesin fine particles having an average particle size of 0.01 to 10 μm or less in a thickness of 10 to 50 μm, wherein the first organic It has been found that a coated metal plate having a glass transition temperature of 10 to 60 ° C. of the coating layer is excellent in human slip resistance during construction and snow-sliding in winter, and can be colored in any color as a roofing material.

(About the first organic coating layer)
In the present embodiment, boron nitride having an average particle diameter of 0.01 to 10 μm is applied to the first organic coating layer (hereinafter sometimes simply referred to as “organic coating layer”) on the outermost layer on one side of the metal plate. 3-30 mass% is contained. There are two roles of boron nitride in this embodiment. One is the melting of snow by absorption of sunlight and the formation of a water film at the interface between the snow and the painted metal plate. The other is the absorption of heat inside the house and the outdoor side of the heat (the roof side). This is the formation of a water film at the interface between snow and the painted metal plate by melting the snow using the release to the surface. Boron nitride is a material that satisfactorily absorbs and emits infrared rays and far infrared rays, which are heat rays. Therefore, such melting of snow becomes possible.

  Carbon black is known as a substance having such properties, but there is a problem that the color of the organic coating layer becomes black as described above. On the other hand, since boron nitride is colorless unlike carbon black, it is possible to finish the roof in an arbitrary color without disturbing coloring with a general pigment or dye.

  The reason why the amount of boron nitride added is defined as 3 to 30% by mass is that if it is less than 3% by mass, the effect of melting snow due to heat absorption and release is insufficient, whereas if it exceeds 30% by mass. This is because the organic coating layer may be peeled off during the processing of the roof material. More preferably, it is 5-20 mass%. The reason why the average particle size is 0.01 to 10 μm is that classification is difficult if it is less than 0.01 μm, and it is difficult to obtain heat absorption and heat dissipation effects. This is because more boron nitride is exposed, resulting in an increase in surface roughness and a decrease in snow slidability. More preferably, it is 0.01-5 micrometers.

  The kind of boron nitride added to the organic coating layer according to this embodiment is not particularly limited, and cubic (zinc flash structure) boron nitride, hexagonal wurtz steel structure boron nitride, hexagonal graphite-like structure Boron nitride or the like can be applied. These can be applied singly or in a mixed state of two or more.

  In the present embodiment, 0.5 to 10% by mass of silica powder having an average particle size of 0.05 to 5 μm is added to the uppermost organic coating layer on one side of the metal plate. There are two roles of the silica powder in this embodiment. One is the addition of a matte appearance, and the other is the improvement of snow sliding performance by forming a wide water film at the interface between snow and painted metal due to the hydrophilicity of silica. A method for imparting a matte appearance by adding silica powder is generally used. Usually, an average particle size of about 3 to 30 μm is used. It was found that the sex was insufficient. Therefore, in this embodiment, snow sliding performance is ensured by making the average particle size 0.05 to 5 μm smaller than usual. Furthermore, the silica having a small average particle diameter according to the present embodiment is more likely to be concentrated on the surface of the organic coating layer than the large one, and this has the effect of expanding the area of the water film formed at the interface between the snow and the painted metal plate. It is possible to impart a realistic snow sliding property.

  The reason why the average particle size of the silica powder is defined as 0.05 to 5 μm is that it is difficult to give a matte appearance if it is less than 0.05 μm, and if it exceeds 5 μm, the matte appearance is obtained. This is because the roughness becomes high and snow sliding performance is lowered. The reason why the amount of silica powder added is 0.5 to 10% by mass is that if the amount is less than 0.5% by mass, sufficient snow-sliding property and matte appearance cannot be obtained sufficiently. This is because although the matte appearance can be obtained, the roughness becomes high and the snow sliding property may be insufficient.

  As described above, the silica powder is added for the matte appearance and the snow-sliding property. Therefore, the silica powder is indispensable for the coating on the outdoor side, but it may be added or not added to the indoor side.

  The kind of silica powder in the first (outdoor side) organic coating layer according to this embodiment is not particularly limited, and contains 60% or more of silicon dioxide, for example, containing quartz as a main component. Natural silica such as silica sand, heat treated silica such as fly ash, synthetic silica obtained by reaction of sodium silicate and acid, synthetic silica obtained by hydrolysis of alkoxysilane, synthetic silica obtained by reaction of calcium silicate and acid, Etc. are applicable. Particularly preferred is a fine powder of natural silica having an excellent matte appearance.

  In this embodiment, 0.1-10 mass% of fluororesin fine particles with an average particle diameter of 0.01-10 micrometers are contained in the organic coating layer of the outermost layer of the single side | surface of a metal plate. The role of the fluororesin fine particles in this embodiment is lubricity.

  The reason why the average particle size of the fluororesin fine particles is limited to 0.01 to 10 μm is that if the average particle size is 0.01 μm or less, the snow-sliding property is insufficient, and if it exceeds 10 μm, it is exposed from the surface of the organic coating layer. This is because the amount of fluororesin to be increased increases the resistance to human slip when constructing a roof.

  The reason why the amount of the fluororesin fine particles added is defined as 0.1 to 10% by mass is less than 0.1% by mass, since there are few fluororesin fine particles present on the surface of the organic coating layer, and sufficient snow sliding properties cannot be imparted. This is because when it exceeds 10% by mass, the slip resistance is poor.

  Thus, since the fluororesin fine particles are added for snow sliding properties, they are essential for outdoor coating, but may be added or not added to the indoor side.

  The kind of fluorine fine particles in the organic coating layer according to the present embodiment is not particularly limited, and generally used fluororesin fine particles can be applied. For example, polytetrafluoroethylene resin, polytetrafluoroethylene-perfluoropropyl vinyl ether copolymer resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-ethylene copolymer resin, polyvinylidene fluoride resin Polyvinyl fluoride resin or the like can be applied. Particularly preferred is a polytetrafluoroethylene resin having a low friction coefficient.

  The glass transition temperature of the organic coating layer which concerns on this embodiment is 10-60 degreeC. The glass transition temperature of the organic coating layer has a great influence on the resistance to human slip. When the temperature of the atmosphere is lower than the glass transition temperature of the organic coating layer of the coated metal plate, the organic coating layer is hard and shows a so-called glass state. Conversely, when the ambient temperature is higher than the glass transition temperature, the organic coating layer is rubbery. It becomes a natural property and becomes viscous.

  Usually, in the snowy areas of Hokkaido, Tohoku, etc., roof construction work is mainly performed in the summer. In this case, the roof temperature often exceeds 60 ° C. Therefore, by setting the glass transition temperature of the organic coating layer to be close to or lower than the temperature of the roof in summer, the organic coating layer becomes viscous when laying the roof, increasing the friction with the shoe of the worker, Make the shoes more slippery and improve the slip resistance. On the other hand, the temperature of the roof in winter is approximately 5 ° C. or lower, which is lower than the glass transition temperature of the organic coating layer of the present embodiment, so that the organic coating layer exhibits a glass state, and snow becomes slippery.

  The reason why the glass transition temperature of the organic coating layer is limited to 10 to 60 ° C. is that if it is less than 10 ° C., the processability of the organic coating layer is lowered, and there is a high possibility that peeling of the organic coating layer occurs during molding. If the temperature exceeds ℃, the roof temperature during roof construction in summer may be lower than the glass transition temperature of the organic coating layer, so the organic coating layer does not exhibit viscosity and may be inferior in human slip resistance. . A more preferable range of the glass transition temperature is 15 to 45 ° C. The glass transition temperature of the organic coating layer in the present invention can be measured using a differential scanning calorimeter (generally called DSC) after peeling off the organic coating layer coated on the metal plate. .

(About the second organic coating layer)
A second organic coating layer (hereinafter simply referred to as “organic coating layer”) that efficiently absorbs heat on the back side of the painted surface (the surface on which the first organic coating layer is formed) of the painted metal plate according to the present embodiment. By absorbing the indoor heat and releasing it to the outside, the temperature of the organic coating layer on the outdoor side can be increased to melt the snow and improve the snow sliding performance. It becomes possible. By applying 5 μm or more of an organic coating layer containing 3 to 30% by mass of at least one of boron nitride or carbon black on the surface opposite to the outdoor surface (indoor side) of the coated metal plate according to this embodiment, the above effect can be obtained. can get.

  As described above, boron nitride and carbon black are substances that efficiently absorb and emit infrared rays and far infrared rays, which are heat rays. The kind of boron nitride is not particularly limited, and cubic (zinc flash structure) boron nitride, hexagonal wurtz steel structure boron nitride, hexagonal graphite-like structure boron nitride, and the like can be applied. The average particle size of the boron nitride powder is not particularly limited, but 10 μm or less equivalent to that on the outdoor side is convenient for producing a paint. These boron nitrides can be used alone or in a mixed state of two or more. In addition, since the back side of the coated metal plate does not require design properties, carbon black with a limited color tone can be used without any problem. The type of carbon black is not particularly limited, and channel black, thermal black, furnace black, acetylene black, and the like can be applied. More preferred are channel black and furnace black. The average particle size of these carbon black powders is not particularly limited, but is preferably 5 to 300 nm. These carbon blacks can be used alone or in a mixed state of two or more.

  The reason why the addition amount of boron nitride and carbon black powder is 3 to 30% by mass is that if the amount is less than 3% by mass, the effect of melting snow by heat absorption and heat dissipation is insufficient, while 30% by mass is added. This is because if it exceeds, the moldability becomes inferior. Especially preferably, it is 5-20 mass%. The reason why the thickness of the organic coating layer is set to 5 μm or more is that if it is less than 5 μm, the effect of melting snow by heat absorption and heat dissipation is insufficient. The upper limit is not particularly limited, but about 20 μm is appropriate considering the balance between cost and performance.

(Resins used for organic coating layers)
The resin used for the organic coating layer according to the present embodiment is not particularly limited as long as the glass transition temperature after coating can be adjusted to a range of 10 to 60 ° C., but considering that it is used outdoors. Those having excellent weather resistance, discoloration resistance, gloss retention and water resistance are preferred. Examples of such resins include polyolefin resins, acrylic resins, urethane resins, epoxy resins, polyester resins, silicon polyester resins, vinyl chloride resins, fluororesins, butyral resins, polycarbonate resins, and phenol resins. Modified products, mixtures and copolymers can also be used. Moreover, an isocyanate resin, an amino resin, a silane coupling agent, or a titanium coupling agent can be used in combination as an auxiliary component.

  For applications where severe processing is applied, resin systems that crosslink polyester resins with melamine, resin systems that crosslink polyester resins with isocyanate, vinyl chloride resins, fluororesins (solvent-soluble, dispersion-mixed with acrylic resins) ) Is desirable. The form as the paint is not particularly limited, and examples thereof include organic solvent paints, water paints, colloidal dispersion paints, and powder paints. The organic coating layer of the coated metal plate according to the present embodiment can be formed by painting a liquid or molten resin coating on the metal plate, or boron nitride, silica powder, or fluorine fine particles according to the present embodiment. It is also possible to produce a film containing, and laminate the metal plate in the film state. Examples of the resin suitable for laminating include a fluororesin, an acrylic resin, a polyvinyl chloride resin, and a PET resin, and a commonly used adhesive or corona discharge may be used in combination.

(About additives)
In the resin-organic coating layer of the coated metal plate according to this embodiment, any additive that is usually added to a paint can be added without any problem. For example, as a pigment, a publicly known thing can be used irrespective of inorganic type, organic type, and a composite system of both, cyanine pigments such as titanium white, zinc yellow, alumina white, and cyanine blue, pyrazolone orange, Examples include azo pigments, bitumen, and condensed polycyclic pigments. Other examples include glittering pigments such as metal pieces, metal oxides, pearl pigments, mica pigments, indigoid dyes, sulfur dyes, phthalocyanine dyes, diphenylmethane dyes, nitro dyes, acridine dyes, and the like. The pigment concentration is not particularly limited, and may be determined according to the necessary color and hiding power. Further, in addition to the color pigment, any pigment that is usually added to a paint can be added without any problem. Examples of such additives include extender pigments such as calcium carbonate, talc, gypsum, and clay, organic crosslinked fine particles, and inorganic fine particles. If necessary, a surface smoothing agent, an ultraviolet absorber, a hindered amine light stabilizer, a viscosity modifier, a curing catalyst, a pigment dispersant, a pigment settling inhibitor, a color separation inhibitor, and the like can be used.

(About average particle size)
The “average particle size” of particles such as boron nitride, silica powder, fluororesin fine particles, and carbon black contained in the organic coating layer of the present invention means the number average particle size of the primary particles, and laser It can be measured by a diffraction method.

(About the thickness of the organic coating layer)
The thickness of the organic coating layer of the coated metal plate according to the present embodiment is 10 to 50 μm in terms of dry film thickness on the surface on the outdoor side. If it is less than 10 μm, sufficient snow sliding properties cannot be imparted. If it exceeds 50 μm, the effect is saturated and it is not economical. A more preferable organic coating layer thickness is 10 to 20 μm. On the other hand, the surface on the indoor side is 5 μm or more. If it is less than 5 μm, there is no coating effect, and a sufficient indoor heat absorption effect cannot be obtained. The upper limit of the film thickness is not particularly limited, but is 50 μm in consideration of the occurrence of wrinkles and costs during manufacturing.

(Regarding the method of forming the organic coating layer)
The organic coating layer of the coated metal plate according to the present embodiment is applied and baked according to the form of the paint using a brush, roll coater, curtain flow coater, roller curtain coater, blade coater, die coater, laminator, etc. It is cured and dried or heated and pressed. In order to bake the paint, it may be heated using a hot air furnace, an induction heating furnace, a near infrared furnace, a far infrared furnace, or an energy beam curing furnace. These may be used in combination.

(About the base metal plate)
The base metal plate of the coated metal plate according to the present embodiment is not particularly limited, but a stainless steel plate, a plated steel plate, and an aluminum alloy plate are suitable. Examples of the stainless steel plate include a ferritic stainless steel plate, a martensitic stainless steel plate, and an austenitic stainless steel plate. As the plated steel sheet, galvanized steel sheet, zinc-iron alloy plated steel sheet, zinc-nickel alloy plated steel sheet, zinc-chromium alloy plated steel sheet, zinc-aluminum alloy plated steel sheet, zinc-aluminum-magnesium alloy plated steel sheet, zinc-aluminum- Examples include magnesium-silicon alloy plated steel sheets, aluminum-silicon alloy plated steel sheets, galvanized stainless steel sheets, aluminum-silicon alloy plated stainless steel sheets. As aluminum alloy plates, JIS1000 series (pure Al series), JIS2000 series (Al-Cu series), JIS3000 series (Al-Mn series), JIS4000 series (Al-Si series), JIS5000 series (Al -Mg system), JIS6000 system (Al-Mg-Si system), JIS7000 system (Al-Zn system), and the like. Among them, a plated steel plate having a good balance between cost and performance is suitable as the base metal plate of the present invention.

  Examples of the pre-coating treatment for the metal plate include washing with water, washing with hot water, pickling, alkali degreasing, grinding, polishing, and the like, and these may be performed alone or in combination as necessary. What is necessary is just to select the conditions of pre-coating treatment suitably.

  Chemical conversion treatment may be performed on the metal plate as necessary. The chemical conversion treatment is performed for the purpose of enhancing the adhesion between the coating and the base metal plate and for improving the corrosion resistance. As the chemical conversion treatment, known techniques can be applied. For example, zinc phosphate treatment, chromate treatment, chromate-free treatment, silane coupling treatment, composite oxide film treatment, tannic acid treatment, titania treatment, zirconia treatment These composite treatments are exemplified.

  For the purpose of improving the corrosion resistance, an undercoat coating having a rust preventive pigment may be provided between the chemical conversion treatment layer and the coating according to the present embodiment. As the rust preventive pigment, known rust preventive pigments can be applied, for example, zinc phosphate, iron phosphate, aluminum phosphate, aluminum tripolyphosphate, zinc phosphite and other phosphate-based rust preventive pigments, calcium molybdate, Molybdate antirust pigments such as aluminum molybdate and barium molybdate, vanadium antirust pigments such as vanadium oxide, ion exchange silica anticorrosion pigments such as calcium ion exchange silica, strontium chromate, zinc chromate, calcium chromate, potassium Chromate rust preventive pigments such as chromate and barium chromate, fine silica such as water-dispersed silica and fumed silica, ferroalloys such as ferrosilicon, and the like can be used. These may be used alone or in combination.

  You may add 3-30 mass% of at least 1 or more types of boron nitride and carbon black to undercoat. As described above, boron nitride and carbon black are substances that efficiently absorb and release heat. Therefore, by adding boron nitride or carbon black to the undercoat layer, the heat inside the roof can be efficiently transmitted to the top coat, and the snow sliding property can be further improved. The thickness of the undercoat layer to which boron nitride or carbon black is added is preferably 3 μm or more. If it is less than 3 μm, the heat transfer effect is insufficient. On the other hand, the upper limit is not particularly limited, but is 10 μm or less from the viewpoint of undercoating.

  The type of boron nitride added to the undercoat layer is not particularly limited, and cubic (zinc flash structure) boron nitride, hexagonal wurtz steel structure boron nitride, and hexagonal graphite-like structure boron nitride should be applied. Can do. The average particle diameter of the boron nitride powder is not particularly limited, but 10 μm or less equivalent to that on the outdoor side is convenient for producing a paint. These boron nitrides can be used alone or in a mixed state of two or more.

  The reason why the addition amount of the carbon black powder and boron nitride is 3 to 30% by mass is that if the amount is less than 3% by mass, the effect of melting snow due to heat absorption and heat dissipation is insufficient. This is because if it exceeds, the moldability becomes inferior. Especially preferably, it is 5-20 mass%. The type of carbon black is not particularly limited, and channel black, thermal black, furnace black, acetylene black, and the like can be applied. More preferred are channel black and furnace black. The average particle size of these carbon black powders is not particularly limited, but is preferably 5 to 300 nm. These carbon blacks can be used alone or in a mixed state of two or more.

  When an undercoat layer containing boron nitride or carbon black is provided, it is more preferable that the coating containing boron nitride or carbon black is also treated on the back side as described above. This is a synergistic effect of the heat transfer improvement effect on the back side and the heat transfer effect on the front side, so that the heat on the indoor side is efficiently transferred to the surface on which snow is placed, promoting the melting of the snow, and the snow and organic coating layer This is because the formation of a water film at the interface is facilitated and the snow sliding property is improved.

  As the resin used for the undercoating according to this embodiment, generally known resins can be applied depending on the application. That is, polyolefin resin, acrylic resin, urethane resin, epoxy resin, polyester resin, silicon polyester resin, vinyl chloride resin, fluorine resin, butyral resin, polycarbonate resin, phenol resin, and the like. Mixtures and copolymers of these can also be used. In addition, an isocyanate resin, an amino resin, a silane coupling agent, a titanium coupling agent, or the like can be used in combination as an auxiliary component.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these at all.

As the metal plate, a molten Zn-11% Al-3% Mg-0.2% Si alloy-plated steel plate having a thickness of 0.8 mm was used. Degreasing treatment (manufactured by Nippon Parkerizing Co., Ltd., FC4670) was performed on the plated steel sheet. Thereafter, washing and drying were performed, and subsequently chromate-free chemical conversion treatment (manufactured by Nippon Parkerizing Co., Ltd., CT-E300) was treated with an adhesion amount of 300 mg / m ² .

  As an undercoat organic coating layer, 30 mass% of aluminum tripolyphosphate (manufactured by Teika Co., Ltd., K-WHITE G105) and Ca ion exchange silica (manufactured by GRACE, SHILDEX C303) are added as a rust preventive pigment at a mass ratio of 1: 1. The modified epoxy resin-based undercoat organic coating layer was formed to a thickness of 3 μm. Furthermore, the level which made the addition amount of a rust preventive pigment 15 mass%, added boron nitride and carbon black, and made the film thickness 3 micrometers was also produced.

  Polyester system containing various boron nitride or carbon black, silica powder, fluororesin fine particles (polytetrafluoroethylene resin) as the topcoat organic coating layer on the undercoat organic coating layer and adjusted to various glass transition temperatures An organic coating layer was painted. In addition, the organic coating layer is made by adding 5% by mass of phthalocyanine blue and coloring it in blue, and in addition to that, by adding 5% by mass of phthalocyanine green and coloring it in green, and adding 5% by mass of red pepper Then, a product colored brown was prepared for evaluation of colorability. Table 1 shows the specifications of the painted surface on the outdoor side (snowfall surface). The indoor side was made of polyester resin as a base and boron nitride and carbon black were added. Table 2 shows the indoor coating specifications.

  The man-made slip resistance, snow-sliding property, workability, and colorability of the coated metal plate produced at each level were evaluated according to the following evaluation criteria, and the results are shown in Tables 3 and 4.

[Evaluation method for human slip resistance]
A simulated roof having a 5 inch slope (26.6 °) with respect to the ground was produced. This simulated roof was exposed outdoors in Ebetsu City in the summer, and a person wearing an underground tabi actually walked on the simulated roof and evaluated the ease of sliding according to the following criteria. ○ The above was accepted.

A: It is difficult to slip.
○: Slightly slippery △: Slightly slippery ×: Very slippery

[Sliding evaluation method]
A hut having a simulated roof with a 5 inch slope (26.6 °) with respect to the ground was produced. This simulated roof was exposed outdoors in Ebetsu City in winter, and the remaining degree of snow during snowfall was visually evaluated over several days, and the relative snow sliding performance was evaluated according to the following criteria. ○ The above was accepted. An air conditioner was installed in the hut, and the room temperature was controlled to be 22 ± 2 ° C.

A: Snow is seen and there is almost no snow on the roof.
○: Snow is seen and there is little snow on the roof.
Δ: Snow sliding is observed, but much snow remains on the roof.
×: No snow sliding is observed.

[Processing evaluation method]
Bend 180 ° with two sheets of the same thickness between them. Adhesive tape (trade name “Cello Tape (registered trademark)” manufactured by Nichiban Co., Ltd.) is applied to the processed part, and it is quickly pulled up 45 ° diagonally. The degree of the organic coating layer peeled and peeled was visually evaluated, and the workability was evaluated according to the following criteria. ○ The above was accepted.

A: No peeling.
○: Peel very slightly (5% or less).
Δ: Peel 25% or more.
X: Peel 50% or more.

[Evaluation method of colorability]
In the case of an organic coating layer to which phthalocyanine blue was added, it was judged acceptable if blue was confirmed visually. In the case of the organic coating layer to which phthalocyanine green was added, it was determined that the green color could be visually confirmed. In the case of the organic coating layer to which the bricks were added, it was judged acceptable if the brown color could be confirmed visually.

  By applying an organic coating layer composed of boron nitride, silica powder, fluororesin fine particles, and glass transition temperature within the range of the present invention from Table 3 to a coated metal plate, good slip resistance and snow sliding properties can be imparted, It turns out that it is excellent also in coloring property. In Table 1, No. 4 shows that the glass transition temperature is as low as 5 ° C., so that it is inferior in workability even though it can satisfy the snow sliding performance and the human slip resistance. No. From 21 to 23, it is understood that the snow sliding property is slightly improved by containing carbon black or boron nitride as the undercoat organic coating layer. No. using carbon black for the topcoat organic coating layer. Although No. 20 is excellent in snow-sliding properties, it is understood that carbon black has a strong influence, and despite the addition of phthalocyanine blue, the color is black and the colorability is inferior. On the other hand, no. No. 20 which was colored blue with phthalocyanine blue other than 20, No. 20 which was colored green with phthalocyanine green. 24, No. 24, brown with brown In No. 25, the color of each color pigment was confirmed by visual observation.

  No. in Tables 4-6. From 21 to 23, it can be seen that by providing an organic coating layer containing boron nitride or carbon black on the back surface, the snow sliding property is further improved.

  As described above, the coated metal plate according to the present embodiment is excellent in colorability, has both human slip resistance and snow sliding properties, can be provided at low cost without the need for complicated processing, It is suitable as a painted metal sheet for roofs.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to this example. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

Claims (3)

As the outermost layer on one side of the metal plate, 3 to 30% by mass of boron nitride having an average particle size of 0.01 to 10 μm, 0.5 to 10% by mass of silica powder having an average particle size of 0.05 to 5 μm, and the average particle size Having a first organic coating layer containing 0.1 to 10% by mass of 0.01 to 10 μm of fluororesin fine particles in a thickness of 10 to 50 μm;
A coated metal sheet, wherein the organic coating layer has a glass transition temperature of 10 to 60 ° C.   5 μm or more of a second organic coating layer containing 3 to 30% by mass of at least one of boron nitride and carbon black on the opposite surface of the metal plate on which the first organic coating layer is formed. The coated metal plate according to claim 1, having a thickness of The painted metal plate according to claim 1, wherein the metal plate is a plated steel plate.