JP4783274B2 - Painted metal plate - Google Patents

Description

  The present invention relates to a coated metal plate that has high decorative properties and good weather resistance and can be suitably used for building materials and the like.

In recent years, with the trend toward higher-grade buildings, it has become necessary to provide complex decorative patterns on the surface of metal plates used as interior materials and exterior materials for building materials. Examples of a method for applying such a decorative pattern include offset printing, screen printing, and ink jet printing. In particular, inkjet printing can easily form a complex multicolor pattern in a short time (see Patent Document 1). A printing layer formed by such ink jet printing or the like is provided with a clear coating film for surface protection.
JP 2001-29883 A JP 2001-105529 A

  However, when such a coated metal plate having a clear coating film and a printing layer is used outdoors, particularly as an exterior material, the clear coating film deteriorates and loses its gloss or permeates the clear coating film. When the light reaches the printing layer, the printing layer may be deteriorated to cause discoloration. In particular, when a complicated multicolor decorative pattern is formed by the printed layer, the sharpness of the decorative pattern is lost due to slight deterioration of the printed layer. Further, when such a clear coating film and a printing layer are precoated on a metal plate, it is also required that the clear coating film is not cracked or peeled off when the coated metal plate is bent.

  The present invention has been made in view of the above points, and is a coated metal plate having a printed layer, which can prevent discoloration of the printed layer and loss of sharpness even when exposed outdoors for a long period of time. An object of the present invention is to provide a coated metal plate that can be bent and has good bending workability.

  The coated metal plate according to the present invention is provided with a hue coating film 3 on the metal plate 2, a printing layer 4 is provided on at least a part of the outer surface of the hue coating film 3, and the outer ring layer of the printing layer 4 has a cyclic aliphatic polyhydric acid. A clear coating film 5 comprising a polyester resin comprising a basic acid and an aliphatic polyhydric alcohol and not containing an aromatic component, and at least one of an ultraviolet absorber and a light stabilizer is provided. For this reason, the clear coating film 5 has excellent adhesion to the hue coating film 3 and the printing layer 4, and even when the coated metal plate 1 is exposed to the outdoors for a long time, the coating film is cracked or peeled off. Etc. can be prevented, and further, discoloration and gloss deterioration of the coating film can be prevented. This is because even if a resin degradation reaction occurs due to light irradiation or the like, the chain reaction of the degradation as described above is blocked by the action of the ultraviolet absorber or the light stabilizer in the clear coating film, and is also generated by the degradation. It is presumed that the physical properties of the resulting product are also less brittle, and these synergistic effects work to provide good weather resistance.

  The print layer 4 is particularly preferably formed by ink jet printing. In this case, a complicated multicolor pattern can be easily formed in a short time by inkjet printing, and the printing layer 4 having a natural texture pattern can be formed at a desired position on the outer layer of the hue coating film 3. it can.

  The cycloaliphatic polybasic acid is preferably hexahydrophthalic anhydride, and the aliphatic polyhydric alcohol preferably contains at least one selected from 1,6-hexanediol and neopentyl glycol. In this way, high flexibility is imparted to the clear coating film, and cracking and peeling of the clear coating film can be remarkably suppressed when the coated metal plate 1 is bent, whereby the painted metal plate The weather resistance of 1 can be further improved.

  The polyester resin preferably has a number average molecular weight of 1000 to 10,000, a hydroxyl value of 20 to 150 mgKOH / g, and a glass transition point of -10 to 60 ° C. In this case, the coating film processability, handling property, solvent resistance, and coating film hardness of the clear coating can be improved with a good balance.

  Moreover, it is preferable that the said ultraviolet absorber is at least 1 type selected from a benzotriazole type ultraviolet absorber and a hydroxyphenyl triazine type ultraviolet absorber, In this case, the weather resistance of the coating metal plate 1 is further improved. Can do.

  The light stabilizer is preferably a hindered amine light stabilizer. In this case, the weather resistance of the coated metal plate 1 can be further improved.

  According to the present invention, it is possible to impart excellent weather resistance to a coated steel sheet provided with a printed layer, and to prevent discoloration and loss of sharpness of a printed layer having a fine pattern. In addition, it has good bending workability, which makes it possible to reduce the cost of coated metal plates, relax restrictions on use, prevent adverse effects on the environment during disposal, and prevent complication of processes during mechanical processing. In addition, a coated metal plate having excellent weather resistance can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described.

  Although the appropriate steel plate etc. can be used as the metal plate 2 used by this invention, For example, plated steel plates, such as a hot-dip aluminum-zinc alloy plating steel plate and a hot dip galvanization steel plate, a stainless steel plate etc. can be mentioned.

  A chemical conversion treatment layer can be formed on the metal plate 2 prior to the formation of the coating film. Examples of the chemical conversion treatment layer include a chromate (chromate) treatment layer, a phosphate treatment layer, and a composite oxide film formation.

  In forming the chromate (chromate) treatment layer, the surface of the metal plate 2 can be treated with an aqueous solution containing hexavalent chromium and an inorganic acid such as sulfuric acid. A layer made of a hydrated oxide containing valent chromium is formed. Moreover, a phosphate process layer is a layer which consists of a 3rd phosphate formed by processing the metal plate 2 surface using the aqueous solution containing a 1st phosphate and phosphoric acid. Examples of the type of phosphate include zinc phosphate, manganese phosphate, and iron phosphate. In addition, the thickness of the chemical conversion treatment layer is generally in the range of 1 to 2 μm in the case of the phosphate treatment layer.

  The hue coating film 3 (color base coating film) formed on the surface of the metal plate 2 is colored by containing an appropriate resin such as polyester, epoxy, acrylic or urethane, and a colorant such as pigment or dye. It can be formed by applying and coating the applied hue paint.

  As the colorant contained in such a hue coating film 3, appropriate ones can be used. Specific examples thereof include, as pigments, titanium oxide, carbon black, iron oxide yellow, iron oxide red ( Bengala), aluminum flakes, mica flakes, colored glass flakes, organic blue (phthalocyanine blue) and the like. Examples of the dye include “AIZEN SPILON dye series” manufactured by Hodogaya Chemical Co., Ltd. The blending ratio of such a colorant in the hue paint is usually preferably 0.1 to 40% by weight, particularly preferably 0.5 to 35% by weight.

  In particular, by adding aluminum powder as a pigment in the hue paint, a metallic appearance can be imparted to the coating film. At this time, it is preferable to mix | blend aluminum powder in a hue coating material so that content in the hue coating film 3 may become the range of 10-25 weight%.

  In the application and film formation of the hue paint, apply by an appropriate method such as spray coating, bar coater coating, roller curtain coater, curtain flow coater, roll coater, etc., then pass through a hot air drying furnace or dielectric heating device etc. A film can be formed by heating and drying. The coating amount and film thickness of the hue coating film 3 are adjusted as appropriate, but it is preferable that the film thickness be in the range of 10 to 20 μm.

  In addition, the lower layer of the hue coating film 3 is used for the purpose of reducing the influence of the metal plate 2 on the coating material to improve the adhesion of the coating film or to provide rust prevention. 6 may be provided. As the undercoat paint (primer) for forming the undercoat paint film 6, an appropriate one such as an epoxy paint or a polyurethane resin paint can be used. Rust preventive pigments and the like can be included. In forming the undercoat film 6, the undercoat paint is applied onto the metal plate 2 by an appropriate method such as spray coating, bar coater coating, roller curtain coater, curtain flow coater, roll coater, etc., and then dried with hot air The undercoat film 6 can be formed by forming a film by heating and drying through a furnace, a dielectric heating device, or the like. The undercoating film 6 can be formed so as to be in close contact with the chemical conversion treatment layer when the chemical conversion treatment layer is provided, and can be formed so as to be in direct contact with the metal plate 2 when no chemical conversion treatment layer is provided. it can. At this time, two or more types of undercoat films 6 having different compositions may be sequentially provided to form a multi-layer undercoat film 6 having two or more layers. The coating amount and film thickness of the undercoat coating film 6 are appropriately adjusted, but it is preferable that the film thickness be in the range of 1 to 10 μm.

  The printing layer 4 is provided on the outer layer of the hue coating film 3. Examples of the method for forming the printing layer 4 include flexographic printing, offset printing, screen printing, and inkjet printing. In providing the printing layer 4, the hue coating film 3 is used as a base, and by providing the printing layer 4 at an appropriate position on the outer surface of the hue coating film 3, an appropriate pattern is formed on the hue coating film 3 as the base. The printed layer 4 having the same can be formed. For example, when the printing layer 4 having a darker brown color is formed on the outer surface of the hue coating film 3 having a brown color, a pattern having a wood-like appearance can be formed. The printing layer 4 may be provided on a part of the outer surface of the hue coating film 3 or may be provided over the entire outer surface of the hue coating film 3.

  In providing the printing layer 4, it is particularly preferable to employ ink jet printing. In this case, a complicated multicolor pattern can be easily formed in a short time.

  Ink-jet printing is a method in which ink droplets are ejected from a printing device (printer) through thin nozzles to form a printing layer 4 directly on the hue coating 3, and an electric action is applied to the ink to form a clear printing layer 4. Obtainable. As a printer used for ink jet printing, a charge control method and a drop-on-demand method are known as industrial ink jets, and an appropriate method can be adopted according to a necessary print design pattern.

  On the other hand, for flexographic printing, offset printing, etc., it is basically possible to use printing materials and inks that are mainly used at present, and specifications according to the purpose and intended printing pattern can be applied. However, when the clear layer 5 is formed immediately in the subsequent process, it is necessary to pay attention to the drying property of the ink.

  As the ink used for forming the printing layer 4, an appropriate pigment-based ink or dye-based ink can be used. However, a clearer pattern can be formed by using a dye-based ink in particular. It is desirable to use a pigment-based ink when an adhesive application is required. Examples of pigments used in pigment-based inks include carbon black, disazo yellow, permanent red, and phthaloshanin blue. Examples of dyes used in dye-based inks include disazo black, monoazo yellow, and amino. Examples thereof include red phenol derivatives and blue metal phthalocyanine.

  In this way, a clear coating containing a polyester resin and at least one of an ultraviolet absorber and a light stabilizer is applied to the outer layer of the hue coating film 3 and the printing layer 4 formed on the metal plate 2, and a film is formed. A clear coating film 5 is formed.

  As said polyester resin, what has the structure which ester-polymerized the monomer component which contains a cyclic aliphatic polybasic acid and aliphatic polyhydric alcohol and does not contain an aromatic component is used. When a chain acid monomer or aromatic monomer is included as a monomer component, there is a risk that sufficient adhesion of the clear coating film 5 to the hue coating film 3 may not be obtained, and cracking or peeling occurs when exposed to the outdoors for a long time. , Discoloration and gloss deterioration may occur, and sufficient weather resistance cannot be obtained.

  An example of the cycloaliphatic polybasic acid is hexahydrophthalic anhydride. Examples of the aliphatic polyhydric alcohol include 1,6-hexanediol, neopentyl glycol, hydrogenated bisphenol A, and the like. In particular, when a polyester resin composed of hexahydrophthalic anhydride and at least one of 1,6-hexanediol and neopentyl glycol is used, the clear coating film 5 can be provided with high flexibility, and the coated metal plate 1 When bending is performed, the occurrence of cracking and peeling of the clear coating film can be remarkably suppressed, and the weather resistance of the coated metal plate 1 can be further improved.

  Such a polyester resin can be produced using a known method.

  The polyester resin preferably has a number average molecular weight of 1,000 to 10,000. When the number average molecular weight is less than 1000, the crosslink density becomes too high when the clear coating film 5 is formed with this clear paint, so that the flexibility is lowered and the workability may be problematic. On the other hand, if the number average molecular weight exceeds 10,000, the viscosity of the solution becomes high, handling becomes difficult, and there is a possibility of causing a problem in the coating workability when a clear coating is used. Further, the hydroxyl value (OH value) of the polyester resin is preferably in the range of 20 to 150 mgKOH / g, and if the hydroxyl value is less than 20 mgKOH / g, the clear coating has low curability and the resulting clear coating film 5 Sufficient film hardness may not be obtained, solvent resistance may be reduced, and if the hydroxyl value exceeds 150 mgKOH / g, the coating processability of the resulting clear coating film 5 may be decreased. Absent. Moreover, the acid value of this polyester resin has the preferable range of 1-25 mgKOH / g. Further, the glass transition temperature of the polyester resin is preferably −10 to 60 ° C. If the glass transition temperature is less than −10 ° C., the hardness of the clear coating film 5 to be obtained may be lowered. When the temperature exceeds 60 ° C., the coating film processability of the clear coating film 5 to be obtained may be lowered, which is not preferable.

  The clear coating preferably contains a curing agent for the polyester resin. Examples of such curing agents include polyisocyanate compounds containing at least two thermally dissociable blocked isocyanate groups in one molecule, melamine, and the like.

  Examples of such polyisocyanate compounds include compounds called isocyanate monomers such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and the like. Examples include those prepared by blocking a part or all of isocyanate groups of a polyisocyanate compound with a blocking agent, such as polyisocyanate derivatives such as biuret bodies, isocyanurate bodies, and adduct bodies of trimethylolpropane. Examples of this blocking agent include, for example, ketoxime blocking agents such as ε-caprolactam, methyl ethyl ketoxime, methyl isoamyl ketoxime, methyl isobutyl ketoxime, and phenol blocking agents such as phenol, cresol, catechol and nitrophenol. And alcohol blocking agents such as isopropanol and trimethylolpropane, and active methylene blocking agents such as malonic acid esters and acetoacetic acid esters. These polyisocyanate compounds may be used alone or in combination of two or more.

  Although the content of the curing agent is appropriately adjusted, in order to give the clear coating film 5 particularly excellent weather resistance, the hydroxyl group in the polyester resin and the reactive functional group (polyisocyanate in the curing agent). In the case of a compound, the molar ratio with the thermally dissociable blocked isocyanate group) is such that the reactive functional group in the curing agent is in the range of 0.8 to 1.5 mol with respect to 1 mol of hydroxyl group in the polyester resin. Is preferred. Moreover, when it contains melamine, it is preferable to make it be the range of 10-50 weight part of melamine with respect to 100 weight part of polyester resins.

  Further, a curing reaction catalyst may be contained in the clear paint. Examples of the curing reaction catalyst include tin compounds and zinc compounds. Examples of tin compounds include tin halides such as tin chloride and tin bromide, and organic tin compounds such as dibutyltin diacetate and dibutyltin dilaurate. Examples of zinc compounds include zinc halides such as zinc chloride and zinc bromide. And zinc salts of organic acids such as zinc octylate and zinc laurate. One kind of tin compound or zinc compound as a curing reaction catalyst may be used, or two or more kinds may be used in combination, or may be used in combination with another curing reaction catalyst. The curing reaction catalyst is preferably used at a ratio of 0.01 to 5% by weight with respect to the total heating residue in the clear paint. If this amount is less than 0.01% by weight, the effect of promoting the curing reaction may not be sufficiently exerted, and if it exceeds 5% by weight, the water resistance and moisture resistance of the clear coating film 5 are reduced, As a result, the stain resistance, decontamination property, weather resistance and the like of the clear coating film 5 may be reduced. From the viewpoint of the balance between the curing speed and the physical properties of the clear coating film 5, a more preferable blending amount of the curing reaction catalyst is in the range of 0.01 to 2% by weight with respect to the total heating residue in the composition.

  Further, as the ultraviolet absorber (UVA), a benzotriazole ultraviolet absorber as shown in the following formula (1), a hydroxyphenyl triazine ultraviolet absorber as shown in the following formulas (2) to (7), and the like are used. These can be used alone or in combination of two or more. Examples of such UV absorbers include product numbers “TINIVIN 384-2”, “TINIVIN 400”, “TINIVIN 411L”, “TINIVIN 900”, “TINIVIN 928” and the like provided by Ciba Specialty Chemicals Co., Ltd. Can be used.

  Further, as the light stabilizer (HALS), high molecular weight type hindered amine light stabilizers as shown in the following formulas (8) and (9), and hindered amine light stabilizers as shown in the following formulas (10) to (13). These can be used alone or in combination of two or more. Examples of such light stabilizers include product numbers “TINUVIN 111 FDL”, “TINUVIN 123”, “TINUVIN 144”, and “TINUVIN 292” provided by Ciba Specialty Chemicals.

  Only one of these ultraviolet absorbers and light stabilizers may be contained in the clear paint, but it is more preferred that both are contained. At this time, the contents of the ultraviolet absorber and the light stabilizer are appropriately adjusted. However, if these contents are excessive, the clear coating film 5 may be markedly yellowed, and the clear paint is preserved. Sometimes, in a low temperature environment, the ultraviolet absorber or the light stabilizer is likely to crystallize and aggregate, and it may be difficult to regenerate it. Therefore, when the clear paint contains only the ultraviolet absorber, the content is preferably in the range of 1 to 3% by weight with respect to the total amount of the resin components in the clear paint, and contains only the light stabilizer. When making it, it is preferable to make the content into the range of 1-3 weight% with respect to the resin component whole quantity. When the ultraviolet absorber and the light stabilizer are used in combination, the content of the ultraviolet absorber is in the range of 0.5 to 3% by weight relative to the total amount of the resin component, and the content of the light stabilizer is the total amount of the resin component. On the other hand, it is preferable that the range is 0.5 to 3% by weight, and the total amount of both is preferably 1 to 5% by weight with respect to the total amount of the resin components.

  When applying clear coating and film formation, spray coating, bar coater coating, roller curtain coater, curtain flow coater, roll coater, etc. are applied to the metal plate 2 on which the hue coating film 3 and the printing layer 4 are formed. The film can be formed by applying by an appropriate method, and then curing and drying by heating through a hot air drying furnace or a dielectric heating device.

  The temperature and time required for curing the clear coating depend on the type of each component and the reaction catalyst used, but are generally in the range of 180 to 250 ° C. and about 10 seconds to several minutes. There are no particular restrictions on the coating amount or film thickness when forming this clear paint, but if it is too thick, there is a risk of wrinkling during film formation, and the film thickness should normally be in the range of 3 to 20 μm. It is preferable.

  The glass transition temperature of the clear coating film 5 thus formed is preferably 10 to 80 ° C. If the glass transition temperature is less than 10 ° C., the coating film hardness may be lowered. If the glass transition temperature exceeds 80 ° C., the workability may decrease, which is not preferable.

  In the coated metal plate 1 such as a coated steel plate configured as described above, the clear coating film 5 has excellent adhesion to the hue coating film 3 and the printed layer 4, and the coated metal plate 1 is outdoors. Even when exposed for a long period of time, it is possible to prevent the coating film from being cracked, peeled off, and the like, and to prevent the coating film from fading and deterioration of gloss. In particular, even when a dye-based ink that is inferior in weather resistance to a pigment-based ink is used as an ink for forming the printed layer 4, the pattern represented by the printed layer 4 maintains its sharpness. The occurrence of defects such as blurring or blurring of the pattern is prevented. This is because even if a resin degradation reaction occurs due to light irradiation or the like, the chain reaction of the degradation as described above is blocked by the action of the ultraviolet absorber or the light stabilizer in the clear coating film, and is also generated by the degradation. The physical properties of the resulting product are also less brittle, and it is assumed that these synergistic effects work to exhibit good weather resistance.

  For this reason, the weather resistance which was excellent in the coating film of the coating metal plate 1 can be provided, Thereby, the cost reduction of the coating metal plate 1, relaxation of the restrictions regarding use, prevention of the bad influence on the environment at the time of disposal, It is possible to obtain a coated metal sheet 1 having excellent weather resistance while preventing complicated processes during mechanical processing.

(Examples 1-11, Comparative Examples 1-4)
The surface of a molten aluminum-galvanized steel sheet having an aluminum content of 55% by weight with a thickness of 0.35 mm was subjected to a coating-type chromate treatment so as to be 40 mg / m ^{2 in} terms of Cr amount.

  Next, an undercoat paint (“NSC667 Primer” manufactured by Nippon Fine Coatings Co., Ltd.) was applied and baked and cured by heating at a final reached plate temperature of 200 ° C. for 30 seconds to form an undercoat film 6 having a thickness of 4 μm. .

  Next, a hue paint ("NSC300HQ brown color" manufactured by Nippon Fine Coatings Co., Ltd .; polyester type; containing carbon black, titanium oxide, iron oxide yellow and iron oxide red) is applied, and the final reached plate temperature is 220 ° C. Baking and hardening by heating for 2 seconds, film thickness 15μm, carbon black content 0.5% by weight, titanium oxide content 3% by weight, iron oxide yellow content 6% by weight, iron oxide red content 6% by weight A hue coating 3 was formed.

  A printed layer 4 having a wood grain pattern was formed on the surface of the hue coating film 3. The printing layer 3 was formed by any one of offset printing, inkjet printing, and flexographic printing.

  At this time, in the case of offset printing, ink (manufactured by Toyo Ink Manufacturing Co., Ltd., Dainichi Seika Kogyo Co., Ltd., etc.) is placed on the plate and transferred to the blanket, and this is transferred onto the hue coating film 3 by forward rotation. The printing layer 4 was formed by transfer.

  In the case of inkjet printing, a pigment-based ink (Dainippon Ink Chemical Co., Ltd., Sakata Inx Co., Ltd., etc.) is used, and printing is performed on the hue coating 3 with an inkjet printer. Formed.

  In the case of flexographic printing, a pigment-based ink (manufactured by Toyo Ink Manufacturing Co., Ltd.) is applied to the convex portions of a plate made using a photosensitive resin, transferred onto the hue coating film 3, and the printing layer. 4 was formed.

  A clear coating film 5 was formed on the outer layer of the hue coating film 3 and the printing layer 4 to obtain a coated steel sheet.

  As the clear paint for forming the clear coating film 5, Examples 1 to 3, 5, 6, 8 to 11 and Comparative Examples 1 and 2 with respect to each polyester resin varnish shown in Tables 1 to 3 Block isocyanate (“Desmodur VPLS 2253” manufactured by Sumika Bayer Urethane Co., Ltd.), which is a crosslinking agent, is blended so that the equivalent ratio of hydroxyl group to isocyanate group is 1: 1.2, and further to 100 parts by weight of polyester resin. On the other hand, as a curing catalyst, 0.5 parts by weight of an organotin catalyst (“SCAT-24” manufactured by Sansha Co., Ltd.), 0.5 parts by weight of an acrylic resin-based surface conditioner, and 0.2% by weight of wax Part (amount of active ingredient) was added.

  Moreover, about Examples 4 and 7 and Comparative Examples 3 and 4, with respect to each polyester resin varnish shown in Tables 1 to 3, melamine resin varnish (Dainippon Ink Chemical Co., Ltd. Min. J-820-60 ") is blended in a solid content ratio of 20 parts by weight with respect to 100 parts by weight of the solid content of the polyester resin, 0.5 parts by weight of the acrylic resin-based surface conditioner, and 0.2% of the wax. Part by weight (active ingredient amount) was added.

  In addition, when a UV absorber (“TINUVIN400” manufactured by Ciba Specialty Chemicals Co., Ltd.) and a light stabilizer (“TINUVIN144” manufactured by Ciba Specialty Chemicals Co., Ltd.) are blended in the clear paint, the required amount of xylol is previously added. It melt | dissolved in and mix | blended.

  Then, this clear paint is applied to the surface of the hue paint with a bar coater, and is baked and cured by heating at a final reached plate temperature of 230 ° C. for 40 seconds to form the clear coating film 5 having the thickness shown in Tables 1 to 3. Formed to obtain a coated steel sheet.

<< Accelerated weathering test 1 >>
About the coated steel plate of each Example and a comparative example, the test based on JISK5400 (1990) 9.8 was performed in the state which adhered and covered the polyester tape to the edge part, and the glossiness by a sunshine carbon arc lamp type | formula at this time The retention rate and hue change were measured. At this time, a continuous irradiation test was performed at a black panel temperature of 83 ° C., and evaluation after 2000 hours was performed according to the following criteria.

Gloss retention ◎… 70% or more.
○: 50% or more and less than 70%.
Δ: 30% or more and less than 50%.
X: Less than 30%.

Hue change ◎ ... 3.0 or less.
○: More than 3.0 and 6.0 or less.
Δ: More than 6.0 and 9.0 or less.
X: Over 9.0.

Pattern residue ○: Pattern pattern is clearly visible.
Δ: The pattern is not easily visible.
X: The pattern design disappears and cannot be visually recognized.

<< Accelerated weather resistance test 2 >>
For the coated steel sheets of each Example and Comparative Example, polyester tape is attached to the edge portion to cover, and an ultra accelerated weathering tester (“SUV-F2” manufactured by Iwasaki Electric Co., Ltd.) and a moisture resistance tester (“CT” manufactured by Suga Tester Co., Ltd.) -3 type "), a UV irradiation test under conditions of an irradiation time of 24 hours, a black panel temperature of 63 ° C. and an ultraviolet intensity of 100 mW / cm ² , a test time of 24 hours, a bath temperature of 50 ° C., and a bath humidity of 98%. The gloss retention and hue change were measured after repeating the test cycle of 10 cycles of the wet test under the above conditions, and evaluation was performed according to the following criteria.

Gloss retention ◎… 70% or more.
○: 50% or more and less than 70%.
Δ: 30% or more and less than 50%.
X: Less than 30%.

Hue change ◎ ... 3.0 or less.
○: More than 3.0 and 6.0 or less.
Δ: More than 6.0 and 9.0 or less.
X: Over 9.0.

《Bending adhesion test》
For the coated steel sheets of each Example and Comparative Example, after bending 180 ° with the coated surface outside at a room temperature of 20 ° C., cellophane adhesive tape was applied to the surface of the bent portion, and was thoroughly rubbed with fingers to adhere. I immediately pulled it off. This test was performed by changing the T number at the time of bending, and the place where the cellophane adhesive tape was peeled off at the bent portion was visually observed and evaluated as follows. The T number is the number of plates having the same thickness as the coated steel plate sandwiched inside the bent portion during bending.
◎… No peeling of coating film by 0T folding.
○: Peeling of the coating occurs at 2T or less.
X: Peeling of the coating occurs at 3T or less.

<Coating hardness>
The hardness of the top coat film of the coated aluminum-zinc alloy plated steel sheet of each example and comparative example was determined in accordance with JIS K5400 (1990) 8.4.2.
○: Cracks in the coating leading to the substrate occur at 3H or higher.
Δ: Cracks in the coating film leading to the substrate occur at H or higher.
X: Cracks in the coating leading to the substrate occur at F or higher.

<Adhesion test>
For each example and comparative example, after the coated steel sheet was immersed in boiling ion exchange water at 98 ° C. or higher for 6 hours and then immersed in ion exchange water at 23 ° C. for 18 hours, this was subjected to 5 cycles. Then, it was dried at room temperature for 2 hours, and then 10 × 10 = 100 film cut grids were made at 1 mm intervals. This coated steel sheet was extruded 6 mm with Erichsen to allow the cellophane adhesive tape to adhere to the coating film, which was immediately peeled off and evaluated according to the following evaluation criteria.
◎… No peeling of clear film.
○: Less than 5% peeling of clear coating film.
X: Peeling of the coating film of 5% or more of the clear coating film or less than the hue coating film occurs.

《Salt spray test》
For each of the examples and comparative examples, the edge of the coated steel sheet cut to dimensions of 7 cm wide and 15 cm long is sealed with polyester tape, and further, the lower region divided into the upper and lower parts of the coated steel sheet is cut with a cutter knife. Two cut flaws intersecting the cross were formed and used as test samples. This test sample is subjected to a salt spray test for 3000 hours by the test method defined in JIS K 5400 9.1, and the occurrence of white rust and blister is observed on the coating film and the cut part of the flat part, and the following evaluation criteria are used. evaluated.
A: There is no abnormality in the upper region, and the rust blistering of the cut portion in the lower region is 5 mm or less on one side.
○: No abnormality in the upper region, and the rust bulge of the cut portion in the lower region is 10 mm or less on one side.
X: Rust blistering occurs in the upper area.

  In Tables 1 to 3, (* 1) is "Death Module VPLS 2253" manufactured by Sumika Bayer Urethane Co., Ltd. (* 2) is "Super Becamine J-820-60" manufactured by Dainippon Ink & Chemicals, Inc. (* 3) is “SCAT-24” manufactured by Sansha Co., Ltd., (* 4) is “TINUVIN400” manufactured by Ciba Specialty Chemicals, and (* 5) is Ciba Specialty Chemicals stock. The company “TINUVIN 144” is shown.

It is a schematic sectional drawing which shows an example of the coating metal plate which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Painted metal plate 2 Metal plate 3 Hue coating 4 Printed layer 5 Clear coating

Claims (6)

  A hue coating (3) is provided on the metal plate (2), a printing layer (4) is provided on at least a part of the outer surface of the hue coating (3), and a cyclic aliphatic group is formed on the outer layer of the printing layer (4). A clear coating film (5) comprising a polyester resin comprising a polybasic acid and an aliphatic polyhydric alcohol and containing no aromatic component and at least one of an ultraviolet absorber and a light stabilizer is provided. Painted metal plate.   The coated metal plate according to claim 1, wherein the printed layer (4) is formed by ink jet printing.   The cycloaliphatic polybasic acid is hexahydrophthalic anhydride, and the aliphatic polyhydric alcohol contains at least one selected from 1,6-hexanediol and neopentyl glycol. Item 3. The painted metal sheet according to item 1 or 2.   4. The polyester resin according to claim 1, wherein the polyester resin has a number average molecular weight of 1,000 to 10,000, a hydroxyl value of 20 to 150 mgKOH / g, and a glass transition point of −10 to 60 ° C. 5. Painted metal plate.   5. The coated metal plate according to claim 1, wherein the ultraviolet absorber is at least one selected from a benzotriazole ultraviolet absorber and a hydroxyphenyltriazine ultraviolet absorber.   The coated metal sheet according to any one of claims 1 to 5, wherein the light stabilizer is a hindered amine light stabilizer.

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