JP2002192059A - Method for manufacturing design metallic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an excellent design metallic sheet which is uniform in coating application density of coating materials over the entire part of the surface of a belt-like metallic sheet by using a rotary atomization sprayer and conrolling the splashing direction and splashing amount of splashing coating material particles. SOLUTION: The method for manufacturing the design metallic sheet comprises the steps of applying a finish coating material by the rotary atomization sprayer to the surface of the belt-like metallic sheet on a continuous color coating line and further applying a coating material of a color tone different from the color tone of the finish coating material thereon while the finish coating material is in dry or undry state, then subjecting the coatings to drying by baking, in which a shielding plate is disposed between the sprayer and the belt-like metallic sheet and the coating application density of the coating materials applied on the belt-like metallic sheet is controlled to be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a coating material on a strip-shaped metal plate while the coating material is in a dry or undried state.
After applying a paint of a further different color on the overcoat film, the present invention relates to a method of manufacturing a design metal plate by baking and drying, and more specifically, by controlling the scattering direction and the amount of the discharged paint, The present invention relates to a method for uniformly producing a fine spot-like or irregular pattern over the entire surface of a strip-shaped metal plate.

[0002]

2. Description of the Related Art Recently, exterior wall materials, interior materials, doors,
There is an increasing demand for high-design precoated steel sheets such as roofing materials. Conventionally, in response to these needs, those having a design-printed film laminated on a steel plate, or a design steel plate directly subjected to a design print and then baked and dried printed steel plates, etc., have been provided. At present, all of the design steel sheets are not very popular because they are very expensive in terms of cost, and the patterns such as patterns are too artificial to be sufficiently satisfactory in decorativeness and designability. . In order to cope with such a situation, recently, a pre-coated steel sheet excellent in design has been proposed by spraying a paint of a color different from that of the top paint into a fine spot-like pattern on the top paint. .

[0003] Such a pattern is obtained by manufacturing a precoated steel sheet, processing it into a sheet, and spraying the sheet processed precoated steel sheet on a separate line. It is also possible to install an air spray device between the second coater and the second open in the continuous coating line of No. 1 to continuously produce in-line.

However, in each case, air spraying is used. In such a method, the size of the pattern is not uniform and the design is inferior. Has the disadvantage that a plurality of devices are required. Recently, instead of such a method, Japanese Patent Application Laid-Open Nos. Hei 8-216331, Hei 9-290211, Hei 11-612, Hei 11-612
76934, and a coating method using a rotary atomizing spray device as disclosed in JP-A-11-77895 and the like.

In these prior arts, a rotary atomizing spray device is generally installed between a second mouth coater and a second baking furnace in a continuous coating line, and spray coating is performed before baking the top coat. After the process of simultaneous baking, it is to produce a painted metal plate with excellent design, and the size and density of the baked pattern is controlled by the rotation of the paint discharge part (nozzle) of the rotary atomizing spray device Number,
Since a desired design is obtained by an appropriate combination of these conditions, since it is affected by a paint discharge amount, a paint viscosity, and the like.

[0006]

The above prior arts are all techniques for forming a pattern having a high design quality on a metal plate. However, a spot pattern is formed on a pre-coated steel plate such as a colored zinc iron plate by a rotary atomizing spray device. When performing the coating, there is a problem that the adhesion amount at the end portion of the metal plate is larger than that at the center portion, and unevenness in density is easily generated.

That is, as shown in FIG. 1, paint particles ejected under the centrifugal force of a spray nozzle 3 that rotates at high speed are applied in a donut shape on a strip-shaped metal plate 1, and a coil-shaped metal plate ( When painting on a steel plate), the painting distance becomes longer toward the outside as compared to immediately below the spray nozzle. In other words, the painting distance becomes longer from the center of the metal plate toward the edge (a <b <in the figure). c), the coating density of the coating material becomes higher toward the edge portion, and the thickness of the coating film becomes uneven in the width direction. Here, a is the coating distance at the center of the metal plate, b is the coating distance from the center of the metal plate toward the end, and c is the coating distance at the end of the metal plate.

That is, when the coating method according to the prior art is used, a uniform coating density cannot be obtained along the width direction of the metal plate. Therefore, in order to obtain a clear pattern, the direction and amount of the paint mist must be controlled as needed. However, a technique that can change these two parameters systematically by easy handling has not been developed. It has not been proposed yet.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a method for spraying paint particles without any modification of a rotary atomizing spray device. An object of the present invention is to provide a method for producing an excellent design metal plate having a uniform coating density over the entire surface of a strip-shaped metal plate by controlling the direction of scattering and the amount of scattering.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to realize the above-mentioned object, and as a result, provided a shielding plate between a rotary atomizing spray device and a band-shaped metal plate. The present inventors have found that a coating film having a uniform coating density can be obtained by controlling the dispersion state of the coating particles applied to the strip-shaped metal plate, and have conceived an invention having the following content as a gist configuration.

That is, in the method for producing a decorative metal plate of the present invention, a top coat is applied to a surface of a band-shaped metal plate by a rotary atomizing spray device on a continuous color coating line.
A method for producing a decorative metal plate by applying a paint of a different color thereon while the top coat is in a dry or undried state, and then baking and drying the same, comprising a rotary atomizing spray device and a belt-like A shielding plate is disposed between the metal plate and the metal plate so as to make the dispersion state of the paint particles applied to the band-shaped metal plate uniform.

As shown in FIG. 3, when a shielding plate of a specific shape is disposed directly above a metal plate in a donut-shaped application area to which a coating material is applied, for example, the metal plate corresponding to the spray nozzle position is formed. A straight line passing through the center and extending in parallel with the longitudinal direction (passing direction) of the metal plate is divided by the shielded portion of the application area. Assuming that the partial lengths of the divided straight lines are a1, a2, a3, and a4, the sum of these partial lengths (a1 + a2 + a3 + a4) is the length of the linear coating area that passes through the center of the metal plate and extends along its longitudinal direction. That is, it represents the coating distance, and it is desirable that the coating distance be formed in a shape such that (a1 + a2 + a3 + a4) = constant at any point on the metal plate.

It is preferable that such a shielding plate is disposed so as to cover the metal plate at two places before and after the metal plate with respect to the spray nozzle position in the passing direction with respect to the center of the metal plate. By forming the legs in such a way that the legs are located outside the strip-shaped metal plate, the extra paint ejected from the nozzle toward the shielding plate and placed on the shielding plate to the outside A shape that is excluded as a drain is preferable.

As shown in FIG. 4, the shielding plate has an elliptical shape that covers the inner diameter of the elliptical paint application area, is wider than the steel plate, and extends in the width direction of the steel plate. Although it is possible, it is not limited to such a shape, the coating distance along a straight line passing through any point on the metal plate and parallel to the passing direction, for example, the metal plate Any shape may be used as long as it is equal to the coating distance at the center.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a method for manufacturing a designable metal plate according to the present invention will be described below with reference to FIGS.

FIG. 2 uses a rotary atomizing spray device (only nozzle 3 is shown) disposed between a second coater and a second oven (baking furnace) in a two-coat two-bake continuous coating line. Next, an outline of a process of uniformly applying a paint to the surface of the strip-shaped steel sheet 1 will be described.

The steel plate 1 has a width of 1 m, and is moved in a direction indicated by an arrow X at a speed of approximately 10 mpm to 200 mpm or less. First, a first coater and a second coater arranged on the upstream side in FIG. After primer coating and baking in one oven, the top coat (polyester white) is applied in the second coater, and subsequently, a paint (polyester black) of a different color from the top coat is applied on the steel sheet 1 by the coating method according to the present invention. Then, by baking in a second oven (induction heating furnace), a desired design metal plate is manufactured.

A shield plate 4 as shown in FIG. 2 is provided between the nozzle 3 of the rotary atomizing spray device and the strip-shaped steel sheet 1 so that the coating particles applied to the strip-shaped steel sheet 1 can be removed. The dispersion state is controlled, and a uniform coating thickness can be obtained.

As shown in FIG. 2, the width along the direction crossing the passing direction (total length L), the width at the end in the passing direction (maximum width Dmax), and the width at the center along the passing direction. The shape and size of the shielding plate can be substantially defined by the width (minimum width Dmin), the inner diameter (radius of curvature R), and the height H of the leg.
(1) Distance between spray nozzle and metal plate to be coated, (2)
Number of rotation of spray nozzle, (3) width of metal plate to be coated,
It is preferable to determine the value by appropriately selecting (4) the discharge amount of the paint, (5) the viscosity of the paint, and the like.

For example, as (1) 30-150c
m, 300-4000 rpm as (2), 400-1500 mm as (3), 50-600 m as (4)
1 / min, (5) as Ford Cup No. 4 in 1
When 5 to 80 seconds is selected, the preferred size of the shielding plate is L = 500 to 1700 mm, Dmax = 100 to
600 mm, Dmin = 5 to 150 mm, H = 10 to 60
0 mm and R = 200 to 800 mm.

[0021]

[Spray conditions]

Paint viscosity: 25 seconds with No.4 Ford cup Paint discharge amount: 400 ml / min Nozzle rotation speed: 1000 rpm Height from steel plate surface to nozzle: 90 cm [Shape and size of shielding plate] Overall length L = 1200 mm, maximum width Dmax = 240 mm, minimum width Dmin = 20 mm, height H = 150 mm, and inner diameter (radius of curvature) R = 650 mm

(Embodiment 2) Discharge rate of paint is 200 ml / m
A design steel sheet was produced in the same manner as in Example 1 except that the in and the nozzle rotation speed were set to 500 rpm.

(Embodiment 3) The discharge amount of paint is 500 ml / m
A design steel sheet was produced in the same manner as in Example 1 except that the in and the nozzle rotation speed were set to 2000 rpm.

(Embodiment 4) The inner diameter R of the shielding plate 4 is 500 m.
m and the total length L were set to 1100 mm, and a design steel sheet was produced in the same manner as in Example 1.

Example 5 A design steel sheet was produced in the same manner as in Example 1 except that the shielding plate 4 was formed in the shape shown in FIG.

Comparative Example 1 A design steel sheet was produced under the same conditions as in Example 1 except that the shielding plate 4 was removed.

Comparative Example 2 The same conditions as in Example 1 were adopted except that the shielding plate 4 was formed into a regular triangle having a side of 50 cm as shown in FIG. A design steel sheet was produced.

Examples 1 to 5 and Comparative Example 1 as described above
The uniformity of coating of the painted design was evaluated by measuring whether or not there was coating unevenness in the width direction with respect to the decorative steel sheet prepared in any one of Examples 1 to 3. Table 1 shows the results. Table 1
As can be seen, in Examples 1 to 5, no uneven coating was observed in the width direction, but in Comparative Examples 1 and 2, uneven coating was observed.

[0029]

[Table 1]

[0030]

As described above, according to the present invention,
By installing a shielding plate between the nozzle that discharges the paint and the metal plate, it is possible to cut off excess paint in the edge direction of the metal plate and improve the uniformity of application density in the coil width direction, It is possible to manufacture a design metal sheet having stable design.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining coating unevenness that occurs at an end of a metal plate when a coating material is applied to a band-shaped metal plate by a rotary atomizing spray device.

FIG. 2 is a diagram for explaining a method for manufacturing a designable metal plate of the present invention.

FIG. 3 is a view showing a shape of a shielding plate used in Examples 1 to 4 of the method for manufacturing a designable metal plate of the present invention.

FIG. 4 is a view showing a shape of a shielding plate used in Embodiment 5 of the method for manufacturing a designable metal plate of the present invention.

FIG. 5 is a view showing the shape of a shielding plate used in Comparative Example 2 of the method for manufacturing a designable metal plate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 strip-shaped metal plate 2 coating film distribution 3 rotary atomizing spray (nozzle) 4 shielding plate 5 leg

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (Reference) B05D 7/14 B05D 7/14 G F-term (Reference) 4D073 AA01 BB03 DB04 DB17 DB19 DB22 DB25 DB29 4D075 AA08 AD16 AE06 BB24Z DA03 DB01 DC10 4F033 AA01 PB16

Claims (2)

[Claims] 1. On a continuous color coating line, a top coat is applied to the surface of a strip-shaped metal plate by a rotary atomizing spray device, and while the top coat is in a dry or undried state, it is further coated thereon. After applying paint of different colors,
In a method of manufacturing a decorative metal plate by baking and drying, a shielding plate is provided between the spray device and the band-shaped metal plate so that the coating density of the paint applied to the band-shaped metal plate is made uniform. A method for producing a designable metal plate, comprising controlling. 2. The shielding plate, when placed in a donut-shaped paint application area by a rotary atomizing spray device, passes through an arbitrary point on the metal plate in the application area. The method according to claim 1, wherein the shape is such that a coating distance formed along a straight line drawn in parallel with the direction is constant.