JPS6125435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method that fully utilizes the structure of the uneven surface to be coated and the viscosity of the paint to enhance the three-dimensional appearance of a hard base decorative surface and improve workability.

Generally, metal plates, such as colored steel plates, have excellent physical properties such as weather resistance, and are widely used in construction panels and other fields. However, when this type of material was used as a building material, it had drawbacks such as poor smoothness and coldness. In an attempt to improve this, for example, a metal plate of this type is embossed to improve these defects, a so-called embossed color steel plate has also been commercialized. However, when this type of colored steel sheet is embossed, cracks, peeling, and other damage are clearly seen with the naked eye or under a microscope, especially in the boundary between the uneven and curved surfaces of the coating film on the surface. In other words, although there is a warranty period of about 10 years for colored steel sheets, this product is bad and rusting and peeling of the paint film were observed after a few days, and the surface paint film due to embossing was damaged. The negative effects were significant. In addition, when simply embossing an uneven surface, the three-dimensional effect is enhanced only by the mechanical unevenness.
Moreover, the depth of the embossing was about 0.3 to 0.8 mm, usually about 0.5 mm, and did not give a very three-dimensional effect.

In order to eliminate such defects, the present invention cures at least one layer on the entire surface of the decorative surface of the uneven surface, a double layer on some of the decorative surface, and a mixture of both coatings, thereby improving the mechanical strength of the uneven surface. The synergistic effect of the effect, the difference in coating thickness between concave and convex surfaces, the embossment of the base, the tone difference in the mixed coating area, the contrast, etc. makes it possible to form a crack-free surface with a three-dimensional effect on the coating. Provide a painting method.

The coating method according to the present invention will be explained in detail below using the drawings.

FIG. 1 is an enlarged process diagram for explaining the coating method according to the present invention, and FIG. 1a shows a surface 2 to be coated of a hard base material 1 or the like. The surface to be painted 2 is a concave surface 3
It is a pattern in which a convex surface 4 and a convex surface 4 are formed arbitrarily or regularly, and the depth is about 0.1 to 2 mm, and the size of the pattern is arbitrary. Also, the concave surface 3 and the convex surface 4
The balance is arbitrary. Furthermore, the boundary portion 5 of the uneven surface is formed to be somewhat curved or at right angles due to processing. FIG. 1b shows the step of forming an undercoat layer 6 over the entire surface 2 to be coated, the thickness of which is about 5 to 80 microns (wet).
As a means for forming this paint layer 6, a coating method such as a spray gun or a curtain flow coater is used.
The viscosity during this application is about 1 to 1000 centipoise at 20°C. Regarding the composition of the paint forming the paint layer 6, synthetic resins as color vehicles include, for example, acrylate resin, polyurethane resin, epoxy resin, melamine resin, alkyd resin, polyester resin, furan resin, vinyl resin, and urea resin. , maleic acid resin, styrene resin, phenolic resin,
These include oil-free polyester, styrenated alkyd resin, aluminum paint, chilimene enamel, vinyl copolymer, polyvinyl butyral, and ethyl cellulose. Further, the pigment used is a pigment having a color different from the base color of the hard substrate 1, that is, a so-called peripheral pigment having at least one of color and lightness different.

Further, in the composition of this paint, the blending ratio (weight ratio) of the color vehicle and the pigment is preferably in the range of about 10:1 to 19:1. This is because a thin coating film can be formed by following sudden changes at the boundary 5 of the convex surface, as will be described later, depending on the relationship between fluidity and elongation of the coating material. FIG. 1c shows a second step of wiping off (removing) the paint layer 6a present on the convex surface 4 of the undercoat paint layer 6 formed on the surface to be painted. This method exposes the underlying hard substrate by applying a single layer of coating on the convex surface. FIG. 1d shows the process of forming a top coat layer 7 on the entire surface to be painted,
For example, use a curtain flow coater or a spray gun to coat approximately 5 to 100 microns (wet).
The viscosity of the paint at this time is approximately 10 to 2000 centipoise. Although not shown, the final step is
For example, the coating method according to the present invention is completed by passing through a drying step by natural drying or forced drying.

Next, an example will be explained.

As upper and lower paints, 3 g of brown pigment, 57 g of acrylic resin (vehicle), and 50 g of thinner (solvent) were stirred to a viscosity of approximately 9.9 seconds using a #4 food cup. In addition, the underlying metal plate (color steel plate, plate thickness 0.27 mm, base color cream color, uneven pattern is as shown in Figure 3, and the depth of the uneven pattern is approximately 0.4 mm.
mm) as shown in FIG. 2, and the coating method according to the present invention is applied only to the surface to be coated. Furthermore, this metal plate moves at a speed of 60 m/s in a fixed direction while maintaining its horizontal position. Further, as a paint application device, curtain flow coaters were arranged at intervals of about 20 mm, and wiping devices using rubber rollers were arranged in multiple stages between them.

Then, by passing the metal plate through a curtain flow coater for forming an undercoat layer, an undercoat layer as shown in FIG. 1b is formed on the surface 2 to be coated (first step). In this case, the coating film is about 10 microns thick when wet. Next, the paint layer 6a on the convex surface 4 of the paint layer 6 is removed in an uncured state using a roller R as shown in FIG. 1c (step 2). Next, the same paint as above is applied in the second stage curtain flow coater, and by passing the paint under this, a top coat layer 7 as shown in FIG. 1d is formed on the surface to be painted 2. (Third step). In this case, the coating thickness was 10 microns wet. Next, this metal plate is fed into a baking furnace, where it passes through a preheating zone for baking in which the temperature is sequentially increased from 100 to 180 degrees for about 10 minutes, and then passes through a baking zone at 200℃ for 1 minute. (4th step). The decorative surface painted in this way has a large amount of resin as a color vehicle, so there is a sudden structural change, and the border area that shows the outline of the so-called convex surface is thin and spreads well, and the density of the pigment is low, resulting in a translucent film. The underlying color is visible through the image, and the contours stand out. Furthermore, there was no lack of coating film or cracks in the boundary portion 5, and excellent weather resistance was exhibited. Furthermore, during painting, the top and bottom paints are the same and can be applied with the same viscosity, eliminating mistakes in the work process.Furthermore, there are no problems with color misalignment between the top and bottom paints or compatibility during application, making it easy to apply. It has features that allow it to work.

As described above, according to the coating method of the present invention, the contrast between the coating thickness of the paint (bottom and top), the base color and the paint is applied to the surface to be painted, which has an uneven spot pattern formed by means such as embossing. The three-dimensional effect is enhanced by the mutual effect of the layers. Since the wet paints have good compatibility and are the same paint, a uniform product can be obtained. A coating film is reliably formed at the boundary area. During the drying process, the difference in film thickness between the concave and convex forms, combined with the vertical positional relationship of the concave forms, results in curing in the same drying time. Furthermore, since the paints used in the coating work have the same viscosity and the same color, there is an advantage that the temperature, control, and coating equipment can be the same.

[Brief explanation of the drawing]

FIGS. 1A to 1D are explanatory diagrams showing an embodiment of the coating method according to the present invention, and FIG. 2 is a perspective view showing an example of a panel having a painted surface according to the above invention. DESCRIPTION OF SYMBOLS 1... Hard base material etc., 2... Surface to be painted, 3... Concave surface, 4... Convex surface, 5... Boundary portion, 6... Undercoat paint layer, 7... Topcoat paint layer.

Claims (1)

[Claims] 1. Apply a paint of a different color from the surface to be painted, with a pigment and color vehicle composition ratio of 1:10 to 1:19 by weight, to the uneven surface to be painted to form an undercoat paint layer. A first step, a second step of removing the paint present on the convex surface while the undercoat layer is uncured, and applying a paint with almost the same color composition as the undercoat to the entire surface to be painted, and applying a topcoat. A third step of forming a layer;
A coating method comprising a fourth step of drying these paint layers.