JPH0316466B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a roofing material in which a metal plate is formed and colored mineral particles are adhered to the entire surface thereof, and a method for manufacturing the same. [Prior Art] Conventionally, there are roofing materials in which colored mineral particles are adhered to the flat or uneven surface of a metal plate using asphalt, synthetic resin emulsion, or synthetic resin paint. It has poor corrosion resistance and weather resistance, and it is extremely difficult to produce decorative steel sheets that meet the "certification standards for noncombustible materials" based on the Building Standards Act, and the areas where they can be used are therefore limited. . In other words, conventional roofing materials are made by spraying aggregate such as natural crushed stone or artificially colored crushed stone onto an asphalt layer provided on a metal plate, such as a galvanized iron plate, to hide the asphalt layer, and then adding synthetic material to the top surface of the asphalt layer. Although it is coated with a resin emulsion, asphalt has weak adhesive strength, so a large amount of coating of about 500 g/m ² is required. However, it is known from experience that in order to pass the certification test as a noncombustible material, the combustible substance in the roofing material components must be around 70g/m ² , so there is no way that the above roofing material is a noncombustible material. cannot be used in fire prevention areas or semi-fire prevention areas. Furthermore, asphalt-based adhesives used in roofing materials have the disadvantage that their adhesive strength deteriorates relatively quickly due to the effects of ultraviolet rays, repeated drying, wetness, and cold temperatures, and water permeation due to snowfall and rainfall, causing crushed stones to fall off. In addition, rainwater penetrates through cracks and pinholes that occur as a result of deterioration, promoting corrosion of the underlying metal plate surface.Furthermore, in the summer, the asphalt layer softens and oozes to the surface, significantly impairing the aesthetic appearance of the roof. It has many drawbacks as a material. Next, in the case of conventional products that use synthetic resin emulsion as a binding material for aggregate, the amount of aggregate spread is generally ^around 1500g/m2 in order to maintain the aesthetic appearance of the roof. However, from the viewpoint of adhesion and painting workability, the mixing ratio of synthetic resin emulsion and aggregate is approximately 1 by weight based on experience.
5, the coating amount of synthetic resin emulsion is approximately 150g/m ² (volatile content: 50 g/m 2 ).
(excluding %). This results in too much combustible material, making it unsuitable as a noncombustible material.
In addition, the water-soluble protective colloid and emulsifying agent remaining in the synthetic resin emulsion reduce the water resistance and cause a whitening phenomenon in which the emulsion is re-emulsified by rainwater or the like.
This promotes corrosion of the underlying metal plate and is therefore not suitable for practical use. In addition, as in Japanese Patent Publication No. 50-32728, aggregate particles are coated with a curable synthetic resin as a binder, coated to a thickness of at least 1 mm, and cured.The specific contents are summarized. Then it looks like this: (1) It has a shape that looks like several roof tiles connected and integrated. (2) Apply anti-rust treatment to galvanized iron plates, etc. as necessary.
Form it into a predetermined tile shape using a press or the like. (3) Colored mineral particles, such as colored silica sand, are mixed with a curable synthetic resin, such as a thermosetting acrylic resin emulsion, as a binder, so that the thickness of the coating layer can be adjusted.
Spray and bake evenly to a thickness of 1.0 mm or more. (4) The particle size distribution of mineral particles is 10 mesh or less;
Preferably 3-8 meshes 5-30%, 80-200
Preferably 100 to 130 meshes remain. (5) The mixing ratio of the binder is adjusted so that the mineral particles are completely covered with the binder and the particles are not exposed on the surface. (6) According to the example, the mixing ratio of mineral particles and hardening synthetic resin is 80 weight ratio to 20 weight ratio. [Problems to be Solved by the Invention] In the known roofing materials as described above, for example, assuming that the dry coating thickness is the lower limit of 1 mm, the required amount of curable synthetic resin to be mixed is approximately 200 g/m ² . In other words, the amount of synthetic resin contained in the dry coating film/m ² =
(Coating film thickness x coating material specific gravity) x synthetic resin ratio x non-volatile content = (1 mm x 2.0) x 0.2 x 0.5 = 0.2 (Kg)/m ² = 200
g/ ^m2 Because the amount of synthetic resin, which is combustible, is high, it cannot be used as a noncombustible material, and most of the colored mineral particles used are fine particles with a size of 0.13 to 0.15 mm. It is in a state where coarse particles of 2.3 to 5.0 mm are scattered, which makes it unfavorable in terms of appearance.In addition, only one type of coating material has various quality characteristics required for roofing materials, such as nonflammability and adhesion. It is extremely difficult to satisfy water resistance, corrosion resistance, chemical resistance, weather resistance, appearance, etc. The present invention improves the shortcomings of the conventional metal sheet roofing materials as described above, passes the noncombustible material certification test, has excellent corrosion resistance, weather resistance, adhesion, water resistance, etc., and has good bending workability. The object of the present invention is to provide a roofing material with excellent appearance and a method for manufacturing the same. [Means for Solving the Problems] The metal plate molded noncombustible roofing material according to the present invention includes a metal plate that is undercoated with a thermosetting synthetic resin containing anticorrosive pigments and is formed into a predetermined roofing material shape. A coating layer of an intermediate coating made of a thermosetting synthetic resin or a thermoplastic synthetic resin to which a flame retardant has been added is formed on the undercoat coating film, and a particle size distribution of 8 to 8 is formed on the intermediate coating layer. 80 to 90% of coarse colored mineral particles of 35 mesh and 10 to 20% of fine colored mineral particles of 35 to 200 mesh are adhered, and the particle adhesive layer is covered with a transparent thermosetting material containing a flame retardant. A coating film of synthetic resin or thermoplastic synthetic resin top coat is formed. In addition, in a method for producing a metal plate molded noncombustible roofing material according to another invention, after a metal plate is undercoated with a thermosetting synthetic resin added with an anticorrosive pigment, the metal plate is coated so that the undercoated surface becomes the surface. After press-forming the board into the specified roof material shape and applying an intermediate coating made of thermosetting synthetic resin or thermoplastic synthetic resin containing a flame retardant to the undercoated surface, immediately paint 8 to 35 meshes. Sprinkle 80 to 90% of coarse mineral particles, then 10 to 20% of colored mineral fine particles of 35 to 200 mesh to fill the gaps between the coarse particles, bake and dry, and then coat the top surface with flame retardant. This is a method in which the material is coated with a top coat made of a transparent thermosetting synthetic resin or thermoplastic synthetic resin, and then baked. [Function] In the present invention, a flame retardant-added heat treatment layer is applied on the undercoat film of a metal plate that has been undercoated with a thermosetting synthetic resin containing anti-rust pigments and formed into a predetermined roof material shape. A coating layer of an intermediate coating made of a curable synthetic resin or a thermoplastic synthetic resin is formed, and a particle size distribution of 8 to 8 is applied on the intermediate coating layer.
35 mesh colored mineral coarse particles 80~90% and 35~
200 mesh of colored mineral fine particles of 10 to 20% are adhered, and a coating film of a transparent thermosetting synthetic resin or thermoplastic synthetic resin top coat containing a flame retardant is formed, covering the particle adhesive layer. It has excellent nonflammability, impact resistance, bending workability, and corrosion resistance.Also, since the colored mineral particles are bonded with both intermediate and top coats, it has excellent adhesion. By limiting the particle size distribution, a roofing material that satisfies the appearance, etc. can be obtained. In addition, a specific method for producing roofing materials is to apply an undercoat to a metal plate with a thermosetting synthetic resin containing anti-rust pigments, and then shape the metal plate into a predetermined roofing material shape so that the undercoated surface becomes the surface. Immediately after applying an intermediate coating made of thermosetting synthetic resin or thermoplastic synthetic resin containing a flame retardant to the undercoated surface, immediately apply 80 to 90 mesh of coarse particles of colored mineral. %, and then 10 to 20% fine particles of colored minerals of 35 to 200 mesh are sprinkled so as to fill the gaps between the coarse particles, baked and dried, and the upper surface is coated with a transparent thermosetting compound with a flame retardant added. Since it is created by coating and baking with a top coat made of resin or thermoplastic synthetic resin, the gaps between coarse particles can be completely filled with fine particles, and the adhesive layer of the particles is coated with a flame retardant. Since it is coated with a clear topcoat film, particles can be prevented from falling off and corrosion resistance can be prevented, and an excellent appearance can be maintained. In addition, each paint requires baking and drying, so
It is possible to form a painted surface with excellent adhesion, weather resistance, water resistance, and corrosion resistance. Furthermore, since a flame retardant is added in the intermediate coating and top coating steps, and the amount of coating is limited, roofing materials with extremely high noncombustibility can be manufactured. In the present invention, colored mineral particles refer to naturally colored or artificially colored natural or artificial inorganic mineral particles, and are hereinafter abbreviated as "particles."
In addition, the wet paint surface coated with intermediate paint is hereinafter referred to as "intermediate paint." The roofing material of the present invention is made up of a large amount of metal plates, undercoat, molding, intermediate coat, particle adhesion, and topcoat. These improvements have been made as a result of repeated performance tests such as performance tests, and each will be explained in detail below. The metal plate that is the material (core material) is often a galvanized iron plate with a thickness of 0.4 to 0.5 mm, but if necessary, aluminum plates, aluminized steel plates, aluminum-zinc alloys, etc.
Metal materials such as plated steel plates and stainless steel plates can be used. These are usually subjected to a chemical conversion treatment with phosphate or the like as a pre-painting treatment to prevent rust and improve paint adhesion to form a chemical conversion film layer. The main purpose of undercoating is to impart corrosion resistance, and to improve this effect, a thermosetting synthetic resin paint containing a rust-preventing pigment such as chromic acid is applied thinly to the metal plate and baked to dry. As the undercoating paint, acrylic resin paint, epoxy resin paint, polyester resin paint, etc. are preferable from the viewpoint of adhesion and corrosion resistance. The metal plate subjected to the above treatment is formed into a tile shape as shown in FIGS. 1 to 4 using, for example, a hydraulic press. Fig. 1 is a plan view of a 7-pitch tile, Fig. 2 is a perspective view of an eaves tile, Fig. 3 is a perspective view of a side tile, and Fig. 4 is a plan view of a 13-pitch tile. Because it has excellent adhesion, it can be processed into shapes that require fine workmanship without any problems. Next, the main purpose of the intermediate coating is to ensure adhesion with the particles described later and to provide nonflammability, but from Table 1 showing the test results regarding paint adhesion, it is classified as thermosetting. It has been found that polyester resin paints and fluororesin paints belonging to the thermoplastic category are desirable.

【table】

[Table] In addition, it is desirable to add pigments with good weather resistance to the intermediate coating paint in order to prevent deterioration due to ultraviolet rays, and the color of the pigment should be determined to have a concealing effect on the base after spray adhesion of the particles, which will be described later. It is best to use a similar color to the particles to enhance the appearance. In the present invention, one of the main purposes is to enhance the flame-blowing properties of the roofing material, and a flame retardant is added to the intermediate coating. As a flame retardant compound, one or a mixture of two or more selected from antimony trioxide (Sb ₂ O ₃ ), halogen phosphorus compounds, aluminum hydroxide [Al(OH) ₃ ], and bromide compounds is used as an intermediate coating. It is added in a range of 20 to 45% by weight based on the fixed content of the paint. As a result of experiments, it was found that if the addition rate of the above-mentioned flame retardant material was less than 20% by weight, it would not be possible to pass the non-combustible material qualification test. It has also been found that when the content exceeds 45% by weight, the water resistance of the intermediate coating film decreases, and furthermore, the adhesion force with the particles decreases. The above-mentioned intermediate coating paint is spray-painted onto a metal plate that has been primed and formed using an electrostatic paint sprayer, air sprayer, or air sprayer. dry coating weight) must be within the range of 20 to 60 g/ ^m2 . In other words, as mentioned above, one purpose of intermediate coating is the adhesion of particles, so the particles are dispersed in a wet state immediately after coating, but if the coating amount is less than 20g/ ^m2 , the adhesion of the particles may be insufficient. Moreover, if the amount exceeds 60 g/m ² , the total amount applied in relation to the amount of top coat applied exceeds 100 g/m ² , and there is a risk of failing the noncombustible material qualification test. Next, the particles to be adhered to the intermediate paint will be described. The features of the present invention lie in the particle size distribution, the method of dispersion, and the amount of dispersion. The purpose of spraying and adhering particles is to provide a roofing material with aesthetics, weather resistance, corrosion resistance, and sound insulation against rain noise, etc., and the quality conditions necessary for this purpose are as follows. (1) It is easy to color and does not discolor or fade during long-term roof use. (2) Low lime content (chemical resistance and difficult to dissolve). (3) High hardness (will not be crushed by impact). (4) Do not absorb moisture (adhesion will be impaired if absorbed). (5) No dust generation. Under the above conditions, for example, colored silica sand and colored basalt are preferable, but other natural colored or artificially colored inorganic grout particles can be used. In addition, regarding particle size distribution, in terms of the exterior design of roofing materials, 8
It is preferable to spray particles in the range of ~35 mesh (particle size 2.36 to 0.42 mm) (hereinafter referred to as Tyler standard sieve mesh) over the entire surface, but this particle size completely fills the gaps between particles and forms an intermediate coating film. It is difficult to completely hide the layers so that they are not exposed. Exposed areas of the intermediate coated surface deteriorate due to ultraviolet rays due to long-term outdoor use, and corrosion resistance decreases due to particles falling off due to decreased adhesion of particles, peeling of the paint film, and occurrence of rust. Therefore, in order to fill the gaps between the particles of 8 to 35 mesh on the intermediate coating surface, in the present invention, particles of 35 to 200 mesh (particle size of 0.42 to 0.07 mm) are mixed therein. The mixing ratio of the former coarse particles at 80 to 90% and the latter fine particles at 10 to 20% is appropriate for the work surface and purpose. The method of dispersing particles will be described later in the manufacturing method, but if the total amount of spraying is less than 1200g/ ^m2 , it will be difficult to sufficiently cover the intermediate coating, and if it exceeds 1600g/ ^m2 , the particles will polymerize. However, this is undesirable as it causes extremely weak adhesion points. In addition, the particles were sprinkled on the dry surface immediately after the intermediate coating to ensure sufficient adhesion, and then heated at approximately 200°C.
A strong adhesive structure is created by baking and drying for 3 minutes. Next, in the present invention, in order to protect the adhesive particle surface from external conditions, further impart non-combustibility to the roofing material, further improve water resistance and weather resistance, and bond the particles more firmly, difficult A top coat of transparent thermosetting synthetic resin or thermoplastic synthetic resin to which a retardant has been added is formed. The quality conditions required for this top coat are as follows. (1) It has good weather resistance, that is, there is little checking (thin cracks that occur on the painted surface) and cracking of the coating film due to yellowing and deterioration caused by ultraviolet rays. (2) Good water resistance and resistance to contamination. (3) Good adhesion to particles. As materials that satisfy the above conditions, thermosetting polyester resin clear paints and thermoplastic fluororesin clear paints are desirable. A mixture of antimony trioxide (Sb ₂ O ₃ ) and a halogen phosphorus compound is effective as a flame retardant to be added, and is mixed in an amount of 15 to 18% by weight based on the solid content of the top coat. If the amount added is less than 15%, it will be difficult to pass the nonflammability certification test, and if it exceeds 18%, the clear coating layer will become whitish, depending on the mixing ratio of antimony oxide, resulting in poor appearance. It is undesirable in terms of design. In addition, if the amount of top coat paint is less than 30g/ ^m2 , it will be difficult to coat it completely covering the particle layer, and if the amount is less than 30g/m2,
If it exceeds m ² , the total coating amount will increase due to the intermediate coating.
If the amount exceeds 100 g/m ² , there is a risk of failing the noncombustible material certification test, and at the same time, the phenomenon of paint sagging due to overcoating is likely to occur. Therefore, the appropriate coating amount is in the range of 30 to 50 g/m ² . The above is a fifth diagram illustrating the structure of the roofing material of the present invention.
It is as shown in the figure. In Fig. 5, 1 is a material metal plate;
For example, in galvanized iron plates, colored iron plates, etc., 2 is a chemical conversion coating layer, 3 is an undercoat coating layer, 4 is an intermediate coating layer, 5 is colored mineral particles, 6 is a topcoat clear coating layer, and 7 is a back coating layer. be. Note that the back coating layer 7 is a thin layer of acrylic paint applied for the purpose of rust prevention. Further, Table 2 shows the results of tests conducted to confirm the nonflammability effect, which is the main objective of the present invention. What is clear from Table 2 is that if the configuration and numerical limitations of the present invention and each desirable resin paint are used, it is certain that it will pass the nonflammable material qualification test, and that paints such as acrylic resin can be used as an intermediate coat and top coat. If used, there is a high probability of failure (Experiments 3 and 6), and even if an appropriate paint is used, if the amount of top coat exceeds 50 g/m ² , some test results will be poor.

[Table] [Example] Next, examples of the present invention and their quality test results will be explained. Example 1 Metal plate: A 0.4 mm thick galvanized iron plate was chemically treated using a phosphoric acid treatment agent, and an acrylic resin paint containing 7 to 8% anti-corrosion pigment was applied as an undercoat using a roll coater, and the plate was baked using a press. It was molded as shown in Figure 1. Intermediate coating: As a flame retardant, antimony oxide,
A fluororesin paint containing a halogen phosphorus compound and aluminum hydroxide added at a fixed ratio of 15, 15, and 10% by weight, respectively, for a total of 40% by weight, was applied at 35g/m ² and particles were sprinkled on it when it was wet. Particles: Colored silica sand (trade name Albel, particle size distribution 8
~35me′87.5%, 35~200me′12.5%) 1400g/
m ² was uniformly distributed on each particle and baked at 200°C for 3 minutes to dry. Top coat: 5% and 10% by weight of antimony oxide and halogen phosphorus compounds as flame retardants are added to the thermoplastic fluororesin clear paint, respectively, in a fixed proportion of the paint, and sprayed uniformly at a coating amount of 36g/ ^m2 . A coating film was formed by drying at 200°C for 3 minutes. Example 2 (Only data different from Example 1 are listed) Metal plate: The undercoat was a polyester resin paint with a coating amount of 40 g/m ² . Intermediate coating: A polyester resin paint containing 20% by weight of antimony oxide as a flame retardant and 15% of a halogen phosphorus compound and 10% of aluminum hydroxide was used in a coating amount of 40 g/m ² . Particles: Colored silica sand was sprinkled at 1490 g/m ² and baked to dry. Top coat film: A thermosetting polyester clear paint was used. Flame retardants Antimony oxide 5% by weight Halogen phosphorus compound 12% by weight Coating amount 40g/m ² were used. The quality test results of the above examples and comparative products are shown in Table 3 below.

[Table] The preparation conditions for each comparative example are as follows. Comparison product 1...Commercially available roofing material, metal plate...0.27mm thick zinc iron plate, chemical conversion treated, intermediate coating...acrylic resin paint coated with colored quartz particles, top coating...acrylic resin clear paint, comparative product 2... ...Imported roofing material, Metal plate...0.45mm thick galvanized iron plate, Intermediate coating...Natural crushed stone coated with Alpha Alto adhesive, Top coating...Synthetic resin clear paint, As is clear from Examples 1 and 2 above. In addition, the roofing material of the present invention has passed the noncombustible material certification test, has excellent impact resistance and bending workability, and is particularly superior to conventional products in corrosion resistance. This metal roofing material has excellent adhesion because it is bonded with paint, and has an excellent aesthetic design due to its limited particle size distribution, and can solve most of the problems and drawbacks of conventional roofing materials. did it. Next, a manufacturing method according to an embodiment of the present invention will be explained in order of manufacturing steps.

【table】

[Table] In addition, spraying in each painting process of intermediate coating and top coating may be done by any method such as electrostatic coating, air spray, airless spray, etc., and can be selected manually or automatically, but the spraying of particles is performed during intermediate coating. It must be completed within 10 minutes after application. A feature of the present invention in dispersing particles is that the dispersion of coarse particles and the dispersion of fine particles are carried out in two separate steps, thereby making it possible to completely fill the gaps between coarse particles with fine particles, The painted surface is not exposed,
It is possible to prevent particles from falling off and a decrease in corrosion resistance due to paint deterioration, and to maintain an excellent appearance. Furthermore, since each paint is baked and dried, it is possible to form a painted surface with excellent adhesion, weather resistance, water resistance, and corrosion resistance. Furthermore, since a flame retardant is added in the intermediate coating and top coating steps, and the amount of coating is limited, roofing materials with extremely high noncombustibility can be manufactured. [Effects of the Invention] As explained above, the present invention provides a coating that is difficult to apply on top of the undercoat film of a metal plate that has been undercoated with a thermosetting synthetic resin containing anti-corrosion pigments and formed into a predetermined roofing material shape. A coating layer of an intermediate coating made of a thermosetting synthetic resin or a thermoplastic synthetic resin to which a retardant has been added is formed, and on the intermediate coating layer, coarse particles of a colored mineral having a particle size distribution of 8 to 35 mesh are applied. 90
Fine particles of colored minerals of 10-20% and 35-200 mesh
% are adhered to each other, and a coating film of a transparent thermosetting synthetic resin or thermoplastic synthetic resin top coat containing a flame retardant is formed covering the particle adhesive layer, so it is non-flammable, It has excellent impact resistance, bending workability, and corrosion resistance, and since the colored mineral particles are bonded with both intermediate and top coats, it has excellent adhesion, and the limited particle size distribution improves appearance. You can obtain roofing materials that satisfy your needs. Further, the roofing material is prepared by applying an undercoat to a metal plate with a thermosetting synthetic resin containing anti-rust pigments, and then press-molding the metal plate into a predetermined roofing shape so that the undercoated surface becomes the surface. Immediately after applying an intermediate coat of thermosetting synthetic resin or thermoplastic synthetic resin containing a flame retardant to the undercoated surface,
Sprinkle 80-90% of colored mineral coarse particles of ~35 mesh, then sprinkle 10-20% of 35-200 mesh of colored mineral fine particles to fill the gaps between the coarse particles, bake and dry, and then The upper surface is coated with a top coat of transparent thermosetting synthetic resin or thermoplastic synthetic resin containing flame retardant and baked, so the gaps between coarse particles are completely filled with fine particles. Since the particle adhesion layer is covered with a transparent topcoat film containing a flame retardant, it is possible to prevent particles from falling off and deterioration of corrosion resistance, and to maintain an excellent appearance. In addition, each paint undergoes a baking drying process, so
It is possible to form a painted surface with excellent adhesion, weather resistance, water resistance, and corrosion resistance. Furthermore, since a flame retardant is added in the intermediate coating and top coating steps, and the amount of coating is limited, it is possible to produce roofing materials with extremely high nonflammability.

[Brief explanation of the drawing]

1 to 4 are a plan view and a perspective view showing an example of the shape of the undercoated metal plate after molding in the present invention, and FIG. 5 is a sectional view showing the structure of the roofing material of the present invention. 1... Material metal plate, 2... Chemical conversion film layer, 3...
Undercoat film layer, 4... Intermediate coat layer, 5... Colored mineral particles, 6... Top coat film layer.

Claims (1)

[Scope of Claims] 1. Heat treatment with a flame retardant added on top of the undercoat film of a metal plate coated with an undercoat of a thermosetting synthetic resin added with anti-corrosion pigments and molded into a predetermined roof material shape. A coating layer of an intermediate coating made of a curable synthetic resin or a thermoplastic synthetic resin is formed, and on the intermediate coating layer, 80 to 90% coarse particles of a colored mineral with a particle size distribution of 8 to 35 mesh and 35 to 35 mesh are applied. 200 mesh of colored mineral fine particles of 10 to 20% are adhered, and a coating film of a transparent thermosetting synthetic resin or thermoplastic synthetic resin top coat containing a flame retardant is formed, covering the particle adhesive layer. A metal plate molded noncombustible roofing material characterized by: 2. The intermediate coating layer is made of one or a mixture of two or more selected from antimony oxide, halogen phosphorus compounds, aluminum hydroxide, and bromide compounds, and contains a flame retardant of 20 to 45% by weight as a fixed proportion of the paint. Depending ^on the intermediate coating material containing
The metal plate molded noncombustible roofing material according to claim 1, characterized in that it is formed of a metal sheet. 3. The top coat is a mixture of antimony trioxide and a halogen phosphorus compound, and the fixed ratio of the paint is 15.
The metal plate according to claim 1 or 2, characterized in that the metal plate is formed with the top coat containing ~18% by weight of flame retardant at a coating amount of 30~50g/ ^m2 . Molded noncombustible roofing material. 4. After applying an undercoat to a metal plate with a thermosetting synthetic resin added with anti-corrosion pigments, press-form the metal plate into a predetermined roofing material shape so that the undercoat surface becomes the surface, and apply an undercoat coating to the undercoat surface. After applying an intermediate coat of thermosetting synthetic resin or thermoplastic synthetic resin containing a repellent, immediately sprinkle 80 to 90% of coarse particles of colored minerals in 8 to 35 meshes, and then apply 35 to 200 meshes of coloring. 10 to 20% of minerals and fine particles are sprinkled to fill the gaps between the coarse particles, baked and dried, and the top surface is coated with a top coat of transparent thermosetting synthetic resin or thermoplastic synthetic resin containing a flame retardant. 1. A method for producing a noncombustible roofing material formed from a metal sheet, the method comprising coating and baking the metal sheet. 5. A flame retardant in which the intermediate coating is a mixture of one or more selected from antimony oxide, halogen phosphorus compounds, aluminum hydroxide, and bromide compounds, and the fixed proportion of the paint is 20 to 45% by weight. 5. The method for manufacturing a noncombustible roofing material formed from a metal sheet according to claim 4, characterized in that the coating amount is 20 to 60 g/m ² . 6 The top coat is a mixture of antimony trioxide and a halogen phosphorus compound, and the fixed ratio of the paint is 15.
The metal sheet molded noncombustible roofing material according to claim 4 or 5, which contains a flame retardant in an amount of ~18% by weight and has an application amount of 30 to 50 g/ ^m2 . manufacturing method. 7 The total amount of spraying of the coarse particles and fine particles is
7. The method for manufacturing a metal sheet molded noncombustible roofing material according to any one of claims 4 to 6, characterized in that the metal sheet is sprayed at a density of 1200 to 1600 g/ ^m2 .