JPH0125683B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for coating asbestos-cement corrugated roof tiles. [Background technology] Conventionally, the surface of asbestos cement corrugated tiles has been painted using a flow coater coating machine, but there is a problem that the coating thickness is thinner in the peaks 4 of the corrugated tiles than in the valleys 5. It was hot. In other words, in FIG. 1, the widths a and b of the flow coater curtain are the same, but the coating lengths L and l of the peaks 4 and valleys 5 of the corrugated tile coated with the widths a and b are L>l. Therefore, there was a problem that the coating film thickness was thinner at the peaks, and the weather resistance and other properties differed depending on each part of the corrugated tile. In addition, asbestos cement corrugated tiles are formed from a flat object into a wavy shape using a press or the like, and as a result, cracks are likely to occur on the top surface of the ridges and at the bottom end of the ridges, and paint can get into the cracks. There was a problem that streaks were formed on the paint surface, making the appearance unsightly. [Object of the Invention] The present invention was invented in view of the above points, and its purpose is to make the surface coating film constant in thickness, so that weather resistance and other properties are the same in each part of the corrugated tile. Another object of the present invention is to provide a coating method for asbestos-cement corrugated roof tiles that makes it difficult for cracks to occur during corrugation and, even if they occur, to make them less noticeable. [Disclosure of the Invention] The coating method for asbestos cement corrugated roof tiles of the present invention involves forming a surface layer 2 having a smaller amount of fiber than the substrate layer 1 on the top of a raw asbestos cement sheet plate, forming this into a corrugated shape, Next, the undercoat 3 is spray-coated so that the amount of coating is larger on the surface of the peaks 4 than on the surface of the valleys 5, and then the topcoat 6 is applied to the surface using a flow coater. This method achieves the above-mentioned object of the present invention. The present invention will be explained in detail below. In the present invention, a surface layer 2 having a smaller amount of fibers than the substrate layer 1 is formed on the top of a blank raw board made of asbestos cement. Here, if the amount of fiber in substrate layer 1 is 10 to 20%, surface layer 2
The amount of fiber is 1 to 5%. In addition to the above-mentioned fibers being randomly arranged on the surface layer 2, it is also colored, and the color is made close to the color of the top coating 6 described later. In this way, a colored surface layer 2 with a smaller amount of fibers is laminated on the substrate layer 1 in a corrugated manner, and then the pigment of the top coat 6 is laminated.
An undercoat 3 having an amount of 10% or less is spray-coated so that the surface of the peaks 4 is coated in a larger amount than the surface of the valleys 5. In this case, for example, the ratio of the amount of coating on the peaks 4 and the valleys 5 should be about 2:1. In addition, the overall coating amount of the undercoat 3 should be set to such an extent that the coating performance does not deteriorate in the valleys 5, for example, 60~
80 g/m ² (clear content: 30 to 40 g/m ² ). After preheating, a top coat 6 is applied to the entire surface using a flow coater, and then baked. Next, Table 1 below shows the coating film test results for Examples of the present invention and Comparative Examples. This test is the result of Yamabe.

〔Effect of the invention〕

In the present invention, a surface layer with a smaller amount of fiber than the substrate layer is formed on the top of the asbestos cement blank raw board, and this is formed into a corrugated shape, and then an undercoat is applied so that the surface of the peaks is the same as the valleys. Spray painting is applied so that the coating amount is larger than that on the surface, and then a top coat is applied to the surface using a flow coater, so the thickness of the coating film at the peaks and valleys is constant, and there are areas with weather resistance and other properties. There is no difference in performance,
Every part of the tile has a certain level of performance, and since the amount of fiber in the surface layer is small, the surface layer moves easily when formed into a corrugated shape, making it difficult for cracks to occur.
Moreover, even if a crack occurs, the base paint is applied, so the crack is filled in by the base paint, and then the top coat is applied, so there will be no streaks along the crack on the paint surface. Since a large amount of base paint is applied to the ridges where cracks are likely to occur, cracks are often hidden and cannot be seen from the outside.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating application to a corrugated tile using a flow coater, and FIG. 2 is a cross-sectional view of a corrugated tile obtained by the present invention, in which 1 is a substrate layer, 2 is a surface layer,
3 is an undercoat paint, 4 is a peak part, 5 is a valley part, and 9 is a top coat paint.

Claims (1)

[Claims] 1. A surface layer with a smaller amount of fiber than the substrate layer is formed on the top of the original asbestos cement raw board, and this is formed into a wave shape, and then the undercoat is applied in a larger amount on the surface of the peaks than on the surface of the valleys. A method of painting corrugated asbestos cement tiles, which is characterized by spray painting the asbestos-cement corrugated tiles in a large amount, and then applying a top coat to the surface using a flow coater.