JPS6249867B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a designed steel plate having an excellent design effect, in which a heat-shrinkable synthetic resin film having a shading pattern is adhered to a vinyl chloride-coated steel plate, and recesses corresponding to the pattern are formed. Traditionally, the methods for adding designs to painted steel sheets are as follows:
Various methods have been used to give designs to so-called laminated steel plates, in which various synthetic resin films are heat-sealed to a vinyl chloride-coated steel plate coated with polyvinyl chloride plastisol and baked, by printing a pattern on the film or using a film. One method is to color the material itself to give it a desired pattern to enhance its design, and the other is to press a metal roll with a predetermined uneven pattern engraved on the surface to a laminated steel plate and mechanically create an uneven pattern on the coating surface of the laminated steel plate. There are two known methods: a method in which a three-dimensional surface shape is imparted by transferring the material to a surface to enhance the design, and a method in which the above-mentioned two methods are combined to further enhance the design. However, the method of printing a pattern on the film or coloring the film itself to give a desired pattern to improve the design quality is difficult to achieve because the pattern added to improve the design quality is two-dimensional. was inferior in In addition, the method of mechanically transferring an uneven pattern to the coating surface of a laminated steel plate to improve the design is expensive to produce metal rolls with engraved patterns, and is not suitable when many types of uneven patterns are required. Each time the pattern changes, metal rolls must be prepared accordingly, resulting in a significant decrease in workability on the production line.Furthermore, it is difficult to express fine and complex uneven patterns on the metal rolls, so uneven patterns are required. It tends to be relatively simple, and it is inferior in design because it is only a concave-convex pattern and there is no change in color or brightness. On the other hand, there is a method of printing a pattern on the film or coloring the film itself to give it a desired pattern, and then mechanically transferring the uneven pattern to the coating surface of the laminated steel plate to improve the design. This is a method to obtain a laminated steel plate with an extremely excellent design due to the mutual effect of changes in color and/or brightness and a three-dimensional uneven pattern, but as mentioned above, the metal used to form the uneven pattern is The rolls are expensive, a large number of metal rolls must be prepared, the workability is poor, the uneven pattern is simple, and it is extremely difficult to match the uneven pattern with the printing or coloring pattern applied to the film. It is difficult and has the drawback that if the same adjustment is not made even slightly, the commercial value of the product will be halved. Therefore, as a method of manufacturing a laminated steel plate with excellent design in which the printed pattern and the uneven pattern are synchronized, for example, a heat-shrinkable synthetic material printed using an ink containing a foaming inhibitor in the vehicle is used. A method has also been proposed in which a sheet material made of a composite of a resin film and a foamed resin layer is used to suppress foaming in the patterned area, thereby varying the amount of foaming in the foamed resin layer to form recesses that match the pattern. However, in this method, the foamed resin layer itself is soft, so even if it is composited onto a base material with a large weight such as a steel plate or steel strip, the uneven pattern will be smoothed out due to the weight of the base material during transportation or storage. However, there were drawbacks that significantly reduced its commercial value over time. Another method, as disclosed in Japanese Patent Publication No. 49-12102, is to form a flexible and transparent film layer with a printed pattern of varying tone and color density on a base material via a photosensitive resin layer. There is also a method for producing a three-dimensional decorative board in which a three-dimensional decorative board is formed by laminating the films together and irradiating ultraviolet rays from the film surface to form an uneven pattern with different depths that is synchronized with the printed pattern on the film surface. The photosensitive resins used are expensive and impractical. As a result of intensive research aimed at eliminating the drawbacks of the conventional methods, the present inventors succeeded in developing the revolutionary method of the present invention, which allows laminated steel plates with excellent design effects to be manufactured easily and inexpensively. That is, the first object of the present invention is to print on the synthetic resin film side surface of a laminated steel plate on which a synthetic resin film with a shading pattern printed on a vinyl chloride coated steel plate is adhered. An object of the present invention is to provide a method for manufacturing a designed steel plate that forms recesses corresponding to a shaded pattern. Another object of the present invention is to provide a method for manufacturing a designed steel sheet in which the formation of recesses corresponding to the above-mentioned shading pattern is carried out at high speed on a continuous line without mechanical or physical embossing. Still another object of the present invention is that the recesses formed corresponding to the light and shade pattern are deep recesses of 20 to 100 μm in depth starting from the vinyl chloride coating layer, which is the base layer, and are extremely aesthetically pleasing. It is an object of the present invention to provide a method for manufacturing a designed steel sheet with a rich three-dimensional effect.
Still another object of the present invention is to provide an industrially superior method for producing a designed steel plate which has very good thermal efficiency and can be manufactured inexpensively and easily. That is, the present invention coats and bakes polyvinyl chloride plastisol on a steel plate to produce a vinyl chloride coating layer with a thickness of 50 to 400 μm,
When the temperature of the vinyl chloride coated steel sheet is cooled to within the range of 100 to 180℃, the shrinkage rate is 0.5 to 3μ thick with a shading pattern printed with ink on one side.
A heat-shrinkable synthetic resin film having a thickness of 35 to 70% and a thickness of 20 to 100μ is supplied at the same speed as the moving speed of the vinyl chloride-coated steel plate, and the printed surface of the heat-shrinkable synthetic resin film is coated with the vinyl chloride-coated steel plate. Immediately after that, near-infrared rays are irradiated from the heat-shrinkable synthetic resin film side onto the vinyl chloride coating layer, so that the maximum depth corresponds to the shading pattern printed on the heat-shrinkable synthetic resin film. The present invention relates to a method for producing a designed steel plate, which comprises producing a designed steel plate having concave portions in the range of 20 to 100 μm formed on its surface. Hereinafter, a method for manufacturing a designed steel sheet according to the present invention will be explained in detail with reference to the drawings. FIG. 1 is an explanatory enlarged cross-sectional view showing the state of a designed steel sheet manufactured by the method for manufacturing a designed steel sheet according to the present invention before it is irradiated with near-infrared rays, and FIG.
FIG. 3 is an explanatory enlarged sectional view showing the state of the designed steel sheet shown in the figure after being irradiated with near-infrared rays, and FIG. 3 is a schematic diagram of an apparatus for carrying out the method for manufacturing the designed steel sheet according to the present invention. In order to manufacture the designed steel sheet according to the present invention, first, the steel sheet 1 is coated with polyvinyl chloride plastisol.
PVC-coated steel sheets are produced by baking. As this steel plate 1, various steel plates are used, such as a cold-rolled steel plate, a galvanized steel plate plated by electroplating or hot-dip galvanizing, and an aluminum-plated steel plate plated by hot-dip galvanizing. can do. In order to manufacture a vinyl chloride-coated steel sheet by painting and baking polyvinyl chloride plastisol on the steel sheet 1, a chemical conversion treatment layer E is first formed on the steel sheet 1 for the purpose of improving the coating film adhesion and corrosion resistance of the steel sheet 1, Next, in order to improve the adhesion of the polyvinyl chloride plastisol to the chemical conversion treated steel sheet 1, a primer coating layer D is applied and formed, and then the polyvinyl chloride plastisol is painted and baked to form a vinyl chloride coating layer C. A method similar to the conventional manufacturing method for vinyl chloride-coated steel sheets is carried out. Thus, when producing a vinyl chloride coated steel sheet, the thickness of the vinyl chloride coating layer C is 50 to 400 mm.
This means that if the thickness of the vinyl chloride coating layer C is less than 50μ, not only will it not be possible to apply polyvinyl chloride plastisol uniformly when industrially roll coating it, but as will be described later, This is because a recess is also formed in the coating layer C, making it impossible to form a deep recess.
This is because if the thickness exceeds μ, not only will the effect of increasing the thickness not be noticeable in forming the recesses, but the price will become too high. Like this, the thickness is 50~
A 400μ thick vinyl chloride coating layer C is formed, and when the vinyl chloride coated steel sheet is cooled to a temperature within the range of 100 to 180°C, it is shaded with ink to a thickness of 0.5 to 3μ on one side. Equipped with ink layer B with a printed pattern, shrinkage rate is 35-70% and thickness is 20-20%.
A heat-shrinkable synthetic resin film A of 100 μm is pressed against the vinyl chloride coating layer C through the ink layer B at the same speed as the moving speed of the vinyl chloride-coated steel plate and with an appropriate tension applied to the heat-shrinkable synthetic resin. Film A is heat-sealed. Here, the type and color of the ink layer B, which prints a light and shade pattern on one side of the heat-shrinkable synthetic resin film A, depends on the blending ratio of the pigment contained in the underlying vinyl chloride coating layer C. However, it does not inhibit the heat fusion between the vinyl chloride coating layer C as the base and the heat-shrinkable synthetic resin film A as the outermost layer, and has light resistance,
Any material can be used as long as it has excellent water resistance and heat resistance, and its thickness is such that the pattern can be clearly distinguished and that it can be clearly printed using ordinary gravure printing, offset printing, letterpress printing, screen printing, etc. According to the conditions, a thickness of 0.5μ or more is required, and the vinyl chloride coating layer C and the heat-shrinkable synthetic resin film A
The thickness is preferably 3 μm or less in order to effectively form a recessed portion without inhibiting thermal fusion with the material. Note that the thickness of the ink layer B may normally be around 1 μm. Further, the shading pattern formed by this ink layer B may be a shading pattern of the same color, or a shading pattern of multiple colors including a dark color such as black, dark brown, or grayish brown, and a light color other than the dark color. The reason why the ink layer B is placed between the vinyl chloride coating layer C and the heat-shrinkable synthetic resin film A is because if the ink layer B is placed on the outermost layer, the design may be damaged due to abrasion, etc., or contamination may occur. There is a risk that the color and luster may deteriorate due to light, and as will be described later, when near infrared rays are irradiated, the effect of the heat extends to the vinyl chloride coating layer C, making it impossible to form deep recesses. This is for a reason. The heat-shrinkable synthetic resin film A on which the ink layer B is printed on one side may be a polyvinyl chloride film or a polymethyl methacrylate film that can be thermally bonded well to the underlying vinyl chloride coating layer C. An acrylic resin film is suitable, and the shrinkage rate is 35 to 70 when heated at 150℃ for about 10 minutes.
%, preferably 40 to 50%, in the width direction and/or length direction. This is because heat-shrinkable synthetic resin films with such shrinkage rates are easily available, and when the ink layer B is heated to a temperature of 250 to 400°C by near-infrared heating, which will be described later, 20 to 100 microns of This is because it satisfies the conditions for forming a recess with a maximum depth within the range of .If the shrinkage rate is less than 35%, the depth of the recess will be shallow and the design effect will not improve, and if the shrinkage rate exceeds 70%. This is because if the depth of the recess becomes too deep and the pattern formed by the ink layer B, cracks, wrinkles, or breaks may occur on the surface of the heat-shrinkable synthetic resin film A. The thickness of this heat-shrinkable synthetic resin film A is 20 to 100μ, preferably 40 to 80μ.
Use μ. In other words, the thicker the heat-shrinkable synthetic resin film A is, the deeper the recesses formed on the surface of the designed steel sheet tend to be, but when the thickness exceeds 100μ, the film becomes expensive. Not only is this not practical, but it is also undesirable because the effect of shrinkage due to heating of the ink layer B by near-infrared rays, which will be described later, does not extend to the surface, and if the thickness is less than 20μ, the underlying vinyl chloride coating Even though the adhesion strength with layer C was insufficient and heat-sealed, there was a risk that heat-shrinkable synthetic resin film A would peel off from vinyl chloride coating layer C during use, and furthermore, the thickness was too thin. This is because it is impossible to form recesses with a maximum depth in the range of 20 to 100 μm on the surface of the designed steel sheet, which is the objective of the present invention. In addition,
In order to enhance the design effect of the designed steel sheets manufactured,
As the heat-shrinkable synthetic resin film A, it is preferable to use one with a glossy surface rather than one with a matte surface. In this way, a laminated steel plate was manufactured in which a chemical conversion treatment layer E, a primer coating layer D, a vinyl chloride coating layer C, an ink layer B, and a heat-shrinkable synthetic resin film A were laminated in this order on a steel plate 1 as shown in FIG. Immediately after,
That is, while the temperature of the laminated steel plate is high, the heat-shrinkable synthetic resin film is irradiated from the A side with near-infrared rays with a wavelength of 0.5 to 3.0μ, preferably 0.7 to 2.0μ from an irradiation device that mainly irradiates the heat-shrinkable synthetic resin. The temperature of the dark colored part of ink layer B through film A is 250
It is heated for a short period of time to a temperature of ~400°C. By this heating, the vinyl chloride coating layer C and the heat-shrinkable synthetic resin film A on both sides of the ink layer B are locally heated only near the dark colored portion of the ink layer, and the heat-shrinkable synthetic resin film A is heated. Due to its shrinkability, only the locally heated portions contract and form recesses on the surface, and the vinyl chloride coating layer C, which has not yet been completely cured, softens again only in the locally heated portions. As a result, a recess shallower than the recess formed on the surface of the heat-shrinkable synthetic resin film A is simultaneously formed at the same position as the recess formed in the heat-shrinkable synthetic resin film A. In the method of the present invention, since recesses are formed not only in the heat-shrinkable synthetic resin film A but also in the vinyl chloride coating layer C, the maximum depth of the recesses formed on the surface of the designed steel sheet is 20 to 100 μm. It is possible to produce a highly designed steel sheet with a very deep depth, and a vinyl chloride-coated steel sheet is used to attach the heat-shrinkable synthetic resin film A to the vinyl chloride coating layer C of the vinyl chloride-coated steel sheet. Since the residual heat after baking the polyvinyl chloride plastisol during manufacturing is used, not only is there no need for adhesives, but thermal energy can be used effectively. Near-infrared rays that selectively heat the ink layer are used to heat the ink layer B between the film A, and since the near-infrared rays are irradiated while the temperature of the laminated steel plate is still high, the thermal energy is further reduced. This means making effective use of it. An embodiment of an apparatus for continuously carrying out the method of the present invention on long steel plates will be described with reference to FIG. A long steel plate 1 is uncoiled from an uncoiler 2, and a chemical conversion treatment layer E is formed in a chemical conversion treatment device 3, and then a primer paint is applied with a coating roll 4, and then the primer paint is baked in a heating furnace 5.
A primer coating layer D is formed by baking. Thereafter, it is coated with polychlorinated plastisol using a coating roll 6 and baked in a baking furnace 7.
A heat-shrinkable synthetic material in which a vinyl chloride coating layer C of 50 to 400 μm is formed to produce a vinyl chloride coated steel plate, and an ink layer B with a light and shade pattern is printed on one side of the vinyl chloride coated steel plate at a temperature of 100 to 180°C. When the resin film A has been cooled to within the optimum thermal fusion temperature range, it is supplied from the film feeding device 8 at the same speed as the moving speed of the steel plate 1 while being tensioned by the tensioning device 9. A heat-shrinkable synthetic resin film A with a shrinkage rate of 35-70% and a thickness of 20-100μ has an ink layer B with a shading pattern printed on one side of the steel plate 1 with a thickness of 0.5-3μ. A laminated steel plate is formed by heat-sealing the vinyl chloride coating layer C on the upper vinyl chloride coating layer C using a laminating roll 10. The laminated steel plate produced in this way is mainly 0.5
The near-infrared rays are irradiated from the heat-shrinkable synthetic resin film A side on the surface of the laminated steel plate from the near-infrared irradiation device 11 that irradiates near-infrared rays with a wavelength of ~3μ to form an ink layer B.
Particularly dark colored parts of the ink layer B are selectively heated.
400℃, which is a safe temperature that will not cause thermal decomposition in a short period of time.
When the temperature reaches 250°C or higher at which the heat-shrinkable synthetic resin film A can stably shrink, it is cooled by the next cooling device 12 and the heat-shrinkable synthetic resin film is formed only in the dark-colored patterned portion of the ink layer B. Since A and the vinyl chloride coating layer C simultaneously form the recesses, a designed steel plate is manufactured, and the manufactured designed steel plate is wound up by the coiler 13. The cross-sectional shape of the designed steel sheet manufactured in this manner is as shown in FIG. Next, an example of the method for manufacturing a designed steel sheet according to the present invention will be described. Example 1 Zero-spangle galvanized steel plate treated with zinc phosphate, which is obtained by hot-dip galvanizing a cold-rolled ordinary steel sheet with a thickness of 0.35 mm [Zinc coating amount: Z25 specified in JIS G3302-1979 "galvanized iron sheet" (Minimum adhesion amount 250g/m ² )]
A primer paint made of acrylic urethane modified epoxy resin manufactured by Kansai Paint Co., Ltd. was applied to a thickness of 5 μm on one side of the substrate, and then baked in an oven. After that, apply Kansai Paint Co., Ltd. over the primer paint.
A cream-white polyvinyl chloride plastisol made of
A vinyl chloride-coated steel sheet was manufactured by applying the coating to a thickness of 100 μm at a speed of 30 m/min, and then passing the sheet through an oven at a speed of 30 m/min to heat the sheet to 210° C. and baking it. After that, a tile pattern was created on one side using a black ink composition with a vinyl chloride acrylic copolymer vehicle manufactured by Dai Nippon Printing Co., Ltd. with a line width of 0.8 mm.
A translucent heat-shrinkable acrylic resin film gravure-printed to an ink film thickness of 1μ [manufactured by Kanebuchi Chemical Co., Ltd., copolymer film of polymethyl methacrylate and butyl acrylate, shrinkage rate]
45~50%, film thickness 50μ] is applied under tension at a speed of 30 m/min, and the vinyl chloride coating layer is printed on a vinyl chloride coated steel plate whose temperature after passing through an oven is 140~160℃. Heat fusion bonding was performed by rubber roll pressure bonding while the surfaces were in contact with each other. Next, the obtained laminated steel plate was immediately exposed to a near-infrared irradiation device (output: 3KW/
Book, using a rod-shaped near-infrared lamp manufactured by Migrapic with a heat generation length of 500 mm, a reflector focal length of 100 mm,
The film surface was irradiated with near-infrared rays (maximum energy wavelength: 1μ) for 7 seconds at a threading speed of 6m/min at an irradiation distance of 50mm directly under the above-mentioned 5 devices in parallel).
Recesses are formed in the heat-shrinkable acrylic resin film and the lower vinyl chloride coating layer in the areas corresponding to the black printed parts of the laminated steel plate, creating a three-dimensional design with a maximum depth of 25μ for the recesses on the surface of the heat-shrinkable acrylic resin film. We were able to produce a steel plate with a design. Example 2 A primer-coated steel plate was manufactured by painting and baking the same primer paint as in Example 1 to a thickness of 5μ on one side of a zero-spangle galvanized steel plate treated with zinc phosphate as in Example 1, and then applying the same primer paint as in Example 1. A polyvinyl chloride-coated steel plate was produced by coating and baking the same polyvinyl chloride plastisol as in Example 1 on a primer paint to a film thickness of 200 μm. After that, a wood grain pattern was printed on one side with a sepia-colored ink composition using a vinyl chloride-acrylic copolymer vehicle manufactured by Dai Nippon Printing Co., Ltd., and the conduit portion of the wood grain pattern was inked by Dai Nippon Printing Co., Ltd.
Gravure printing was carried out using a blackish brown ink composition containing a PVC-acrylic copolymer manufactured by Co., Ltd. as a vehicle, with a line width of 0.2 to 0.8 mm and an ink film thickness of 1 μm. Same translucent heat shrinkability as in Example 1. An acrylic resin film and a transparent heat-shrinkable polyvinyl chloride resin film (manufactured by Sanpo Jushi Co., Ltd., shrinkage rate 40-50%, film thickness 40 μm) were each separately heated at the same speed as the vinyl chloride-coated steel sheet by applying tension. The vinyl chloride coating layer of the vinyl chloride coated steel plate and the printed surface were in contact with each other at 140 to 160°C and were thermally fused by rubber roll pressure bonding. Immediately after that, the two types of laminated steel plates obtained were immediately irradiated with near-infrared rays on the film surface under the same conditions as in Example 1 using the same near-infrared irradiation device as in Example 1. In the heat-shrinkable acrylic resin film, a recess is formed between the heat-shrinkable polyvinyl chloride resin film and the lower vinyl chloride coating layer, and the maximum depth of the recess on the heat-shrinkable film surface is It was possible to produce a designed steel plate with a three-dimensional design of 65μ and 80μ in the case of heat-shrinkable polyvinyl chloride resin film. Example 3 A primer-coated steel sheet was manufactured by painting and baking the same primer paint as in Example 1 to a thickness of 50μ on one side of a zero spangle galvanized steel sheet treated with zinc phosphate as in Example 1, and then applying the same primer paint as in Example 1. The same polyvinyl chloride plastisol as in Example 1 was coated on the primer paint to a film thickness of 100 μm and baked to produce a vinyl chloride-coated steel sheet. Thereafter, a transparent heat-shrinkable acrylic resin film was gravure printed with a tile pattern on one side using the same black ink composition as in Example 1 with a line width of 0.8 mm and an ink film thickness of 2 μm [Kanebuchi Chemical Co., Ltd.] Co., Ltd., shrinkage rate 40-45%,
[film thickness 75μ] was applied with tension and heat-fused by rubber roll pressure bonding at the same speed as the vinyl chloride-coated steel plate, with the vinyl chloride coating layer of the vinyl chloride-coated steel plate and the printed surface being in contact with each other at 170°C. Next, with the obtained laminated steel plate at a temperature of 120 to 140°C, the film surface was irradiated with near-infrared rays under the same conditions as in Example 1 using the same near-infrared irradiation device as in Example 1. As a result, the black printed portion of the laminated steel plate It is possible to produce a designed steel sheet with a three-dimensional design in which depressions are formed in the corresponding portions of the heat-shrinkable acrylic resin film and the lower vinyl chloride coating layer, and the maximum depth of the depressions on the surface of the heat-shrinkable film is 40μ. did it. Example 4 A cold-rolled ordinary steel sheet with a thickness of 0.4 mm was treated with zinc phosphate, and one side of the sheet was coated with the same primer paint as in Example 1 and baked to the same thickness as in Example 1. Thereafter, the same polyvinyl chloride plastisol as in Example 1 was coated and baked on the primer paint to a thickness of 150 μm to produce a vinyl chloride-coated steel sheet. After that, a wood grain pattern was printed on one side with a beige-colored ink composition using a PVC-acrylic copolymer vehicle manufactured by Dai Nippon Printing Co., Ltd., and a PVC manufactured by Dai Nippon Printing Co., Ltd. was printed on the conduit portion of the wood grain pattern. - A black ink composition that uses an acrylic copolymer as a vehicle to improve line width.
The same translucent heat-shrinkable acrylic resin film as in Example 1, which was gravure printed to give an ink film thickness of 1 μm at 0.2 to 0.8 mm, was then heated at 160 to 180°C at the same speed as the vinyl chloride-coated steel sheet. The vinyl chloride coating layer of the vinyl chloride-coated steel plate and the printed surface were heat-sealed by rubber roll pressure bonding in a state in which they were in contact with each other. Next, the film surface of the obtained laminated steel plate was immediately irradiated with near-infrared rays using the same near-infrared irradiation device as in Example 1 under the same conditions as in Example 1, and the heat shrinkage of the portion corresponding to the black printed part of the laminated steel plate was confirmed. Recesses were formed between the acrylic resin film and the lower vinyl chloride coating layer, and it was possible to produce a designed steel sheet with a three-dimensional design in which the maximum depth of the recesses on the surface of the heat-shrinkable film was 70 μm. Example 5 Zinc phosphate treatment was applied to an aluminized steel plate made by hot-dipping aluminum to a thickness of 40μ on a cold-rolled ordinary steel plate with a thickness of 0.5 mm, and one side of the aluminized steel plate was treated with the same conditions as in Example 4. A vinyl chloride-coated steel plate was produced by painting and baking a primer paint and polyvinyl chloride plastisol, and then a laminated steel plate was produced by heat-sealing the same translucent heat-shrinkable acrylic resin film as in Example 4. . Next, the obtained laminated steel plate was immediately prepared in Example 4.
When the film surface was irradiated with near-infrared rays under the same conditions as described above, a designed steel plate having a three-dimensional design similar to that of Example 4 could be manufactured. Example 6 After manufacturing a primer-coated steel plate under the same conditions as in Example 1, the polyvinyl chloride plastisol used in Example 1 was then applied to a coating thickness of 100μ, and the baking temperature of the polyvinyl chloride plastisol was varied. Then, a heat-shrinkable acrylic resin film printed with the same tile pattern as in Example 1 was heat-sealed to produce a laminated steel plate, and then immediately under the same conditions as in Example 1 using the same near-infrared irradiation equipment as in Example 1. A designed steel sheet was produced by irradiation with near-infrared rays, and the results of investigating the influence of the baking temperature of polyvinyl chloride plastisol on the workability and adhesion of the coating film of the obtained designed steel sheet are shown in the table. Note that a laminated steel plate that is not irradiated with near-infrared rays was used as a comparative material. In the workability test, the processed part was 3 mm thick at 20°C.
Impact deformation was performed using a Gardner impact tester with a load of 1.82 lb x height of 750 mm so that the bending radius was doubled, and coating film cracking at the bent portion was evaluated using the following evaluation criteria. ◎ No abnormality 〇 Very slight cracking occurs △ Slight cracking occurs × Significant cracking occurs Adhesion test was performed by immersing in boiling water for 4 hours at 20℃ humidity
After being left in a constant temperature and humidity atmosphere of 60% for 24 hours, the coating film was forcibly peeled off, and the degree of peeling was evaluated using the following evaluation criteria. ◎ No abnormalities 〇 Very slight peeling △ Slight peeling × Easy peeling

[Table] From the above results, it was confirmed that the designed steel sheet manufactured by the method of the present invention, which irradiates with near-infrared rays, has improved workability and coating adhesion compared to comparative materials. It was observed that the baking temperature of polyvinyl chloride plastisol had little effect on membrane performance. As detailed above, the method for producing a designed steel sheet according to the present invention involves painting and baking polyvinyl chloride plastisol on a steel sheet so that the thickness of the vinyl chloride coating layer is 50 to 50 mm.
A heat-shrinkable composite with a thickness of 20 to 100 μm is produced by manufacturing a 400μ PVC-coated steel plate, and using the residual heat from baking the PVC plastisol of the PVC-coated steel plate, a shading pattern is printed with ink on one side. A laminated steel plate is manufactured by heat-sealing a resin film so that the printed surface is in contact with the vinyl chloride coating layer of a vinyl chloride-coated steel plate, and then the laminated steel plate is heated in a still hot temperature range of 100 to 180°C. The heat-shrinkable synthetic resin film is irradiated with near-infrared rays from the side to selectively heat the dark-colored printed surface, softening and shrinking the heat-shrinkable synthetic resin film in areas corresponding to the shading pattern formed by the ink layer. A design that utilizes the characteristics to form concavities with a maximum depth of 20 to 100μ on the surface, and has a concave-convex pattern on the surface that is easy to work with, is rich in realism and beauty, and has an excellent decorative effect and three-dimensional effect. The present invention relates to a method of manufacturing a steel plate.
The resulting decorative steel sheets can be used in a wide variety of fields, including interior materials for buildings and vehicles, materials for shutters, and decorative steel sheets for vending machines, home appliances, office equipment, furniture, and cabinets. It is. Furthermore, the method of the present invention has various advantages as listed below, and its industrial value is extremely large. (1) This is a method for manufacturing decorative steel sheets from laminated steel sheets in which a printing ink layer with a dark and light pattern exists between the outermost heat-shrinkable synthetic resin film and the vinyl chloride coating layer that serves as the base layer. Designed steel sheets are less susceptible to deterioration of the color, shading, and gloss of the printed pattern due to surface abrasion or contamination. (2) The polyvinyl chloride plastisol that will serve as the base layer is baked on the steel plate by two methods: normal baking before heat-sealing the heat-shrinkable synthetic resin film, and baking using near-infrared irradiation to heat the printing ink layer. Since it is performed using two-stage heating, the baking temperature can be controlled lower than that of normal baking to form the optimal vinyl chloride coating layer, saving thermal energy and reducing near-infrared irradiation. Since the process is carried out in a state where the laminated steel plate has sufficient heat immediately after heat-sealing the heat-shrinkable synthetic resin film with a shaded pattern printed on the vinyl chloride coating layer, preheating is not required at all. Since the printed portion can be easily heated to a desired temperature and a recessed portion corresponding to the pattern printed portion can be effectively formed, thermal energy can be used effectively. (3) When forming recesses corresponding to pattern printing areas, there is no need to use metal mold rolls or the like as in the past, and recesses corresponding to fine or complex patterns can be easily formed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory enlarged cross-sectional view showing the state of a designed steel sheet manufactured by the method for manufacturing a designed steel sheet according to the present invention before it is irradiated with near-infrared rays, and FIG.
FIG. 3 is an explanatory enlarged sectional view showing the state of the designed steel sheet shown in the figure after being irradiated with near-infrared rays, and FIG. 3 is a schematic diagram of an apparatus for carrying out the method for manufacturing the designed steel sheet according to the present invention. DESCRIPTION OF SYMBOLS 1... Steel plate, 2... Uncoiler, 3... Chemical conversion treatment equipment, 4... Coating roll, 5... Baking heating furnace, 6... Coating roll, 7... Baking heating furnace, 8
...Film feeding device, 9...Tension applying device, 1
0... Laminating roll, 11... Near-infrared irradiation device, 12... Cooling device, 13... Coiler, A
... Heat-shrinkable synthetic resin film, B ... Ink layer, C ... Vinyl chloride coating layer, D ... Primer coating layer, E ... Chemical conversion treatment layer.

Claims (1)

[Claims] 1. Painting polyvinyl chloride plastisol on a steel plate.
After baking, the thickness of the vinyl chloride coating layer is 50~400μ
A vinyl chloride coated steel plate is manufactured, and when the temperature of the vinyl chloride coated steel plate is cooled to within the range of 100 to 180℃, a shading pattern is printed with ink to a thickness of 0.5 to 3μ on one side. A heat-shrinkable synthetic resin film having a shrinkage rate of 35 to 70% and a thickness of 20 to 100μ is fed at the same speed as the vinyl chloride-coated steel plate, and the printed surface of the heat-shrinkable synthetic resin film is It is heat-sealed onto the vinyl chloride coating layer of a vinyl chloride-coated steel plate, and immediately after that, near-infrared rays are irradiated from the heat-shrinkable synthetic resin film side to correspond to the shading pattern printed on the heat-shrinkable synthetic resin film. 1. A method for producing a designed steel plate, which comprises producing a designed steel plate having a surface formed with recesses having a maximum depth of 20 to 100μ. 2. The method for manufacturing a designed steel sheet according to claim 1, wherein near-infrared irradiation is performed using an irradiation device that mainly irradiates near-infrared rays with a wavelength of 0.5 to 3.0 μ. 3 Near infrared rays are printed on a heat-shrinkable synthetic resin film when the temperature of the dark ink on the printed surface is 250 to 400℃.
A method for manufacturing a designed steel sheet according to claim 1 or 2, in which irradiation is performed under conditions such that: 4 Claim 1 in which a cold-rolled steel plate is used as the steel plate coated with polyvinyl chloride plastisol
A method for manufacturing a designed steel sheet according to any one of paragraphs to paragraphs 3 to 3. 5. The method for manufacturing a designed steel sheet according to any one of claims 1 to 3, wherein a galvanized steel sheet is used as the steel sheet coated with polyvinyl chloride plastisol. 6. The method for manufacturing a designed steel sheet according to any one of claims 1 to 3, wherein an aluminum-plated steel sheet is used as the steel sheet coated with polyvinyl chloride plastisol. 7. The method for producing a designed steel sheet according to any one of claims 1 to 6, wherein a polyvinyl chloride film is used as the heat-shrinkable synthetic resin film. 8. The method for manufacturing a designed steel sheet according to any one of claims 1 to 6, wherein an acrylic resin film is used as the heat-shrinkable synthetic resin film.