JPH04300676A - Method for coating inorganic building material - Google Patents

Abstract

PURPOSE:To obtain a good film with uniform thickness on the whole of an inorg. building material inclusive of the side surface thereof in good yield by applying electrostatic painting to the whole of the front and rear of the inorg. building material simultaneously or successively. CONSTITUTION:A panel 11 such as an autoclave-cured aerated concrete panel is arranged in an air jet type electrostatic painting apparatus. Spray guns 14 for electrostatic painting are respectively arranged on the sides of the front 12 and rear 13 of the panel 11 in said apparatus and paint is sprayed to the front 12 and rear 13 of the panel 11 from the spray guns 14. Whereupon, paint particles 15 are bonded to the panel 11 by electrostatic attraction force to form films 16. By this method, a good film with uniform thickness is obtained on an object having a complicated shape over the entire surface thereof.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a method for coating inorganic building materials, and can be applied to the entire surface coating of inorganic building materials such as ALC panels.

0002

BACKGROUND ART For example, ALC (autoclaved aerated concrete) panels are used as wall panels of unit houses. This type of ALC panel is made by pouring a concrete slurry containing air bubbles into a mold, which is mainly made of cement and silica sand, and hardening it first, then steaming it in a high temperature, high pressure autoclave. Manufactured by curing.

[0003] Thereafter, the manufactured ALC panel is coated to improve its waterproof and moisture-proof properties. It is desirable to apply this coating to the entire surface in order to improve the dimensional stability and durability of the object to be coated. Conventionally, as a method for painting the entire surface of such a panel, painting using air spray or airless spray, dipping painting, etc. have been used.

0004

[Problems to be Solved by the Invention] According to the above-mentioned painting method using air spray, the yield is about 30% on average.
The problem is that it is low. Further, a coating method using an airless spray improves the yield to about 60%, but the coating machine is prone to breakdowns and clogging, which increases the burden of maintenance. Moreover, with these spraying methods, even if a good film is obtained on the surface where the paint is directly sprayed by the spray gun, the paint does not adhere to the sides at the same time, and in order to paint the sides, it is necessary to spray from the side as well. It was time consuming because it had to be done.

Furthermore, according to the dip coating method, it is difficult to control the paint, and for example, especially in the case of inorganic building materials, there are problems such as foreign matter getting into the paint and a pot life of the liquid. be. In addition, there is also the disadvantage that the coating film tends to be defective due to non-uniform film thickness. An object of the present invention is to provide a coating method for inorganic building materials that has a high yield and provides a good coating film.

[0006]

[Means for Solving the Problems] The method for coating inorganic building materials according to the present invention is characterized in that electrostatic coating is applied to the front and back surfaces of the building materials, respectively, and the entire surface of the building materials is coated. Electrostatic painting on the front and back sides of building materials can be done simultaneously by placing electrostatic paint machines on the front and back sides, respectively, or by using the same electrostatic paint machine and turning the building materials over and painting on the front and back sides. The sides may be painted sequentially.

The inorganic building materials include ALC (autoclaved aerated concrete) panels, ceramic siding materials, and PC (precast concrete) boards. As a specific method for the electrostatic coating, air atomization electrostatic coating, airless electrostatic coating, etc. can be used.

[0008]

[Effect] By applying electrostatic coating to the front and back surfaces of inorganic building materials, a good coating film with uniform thickness can be obtained on the entire building material, including the sides, and the yield is high. Painting becomes possible.

[0009]

[Example] An example in which the present invention is applied to coating an ALC panel will be described. First, a lightweight aerated concrete slurry is poured into a molding frame covered with a patterned sheet and allowed to cure for a predetermined period of time to temporarily harden the concrete slurry. Next, the formed panel is transported into an autoclave and subjected to autoclave curing, for example, at 180° C., 10 atm, and 8 hours. After completion of this autoclave curing, the panel is removed from the autoclave.

Next, as shown in FIG.
is placed in an air atomizing electrostatic coating device. In this device, spray guns 14 for electrostatic painting are provided on the front 12 side and the back 13 side of the panel 11, respectively. Then, the paint is simultaneously ejected from these spray guns 14 toward the front 12 and back 13 of the panel 11, and the paint particles 1
5 is attached to the panel 11 by electrostatic attraction to form a coating film 16.
form.

That is, by applying a negative DC high voltage to each spray gun 14 and a positive DC high voltage to the panel 11, electrostatic lines of force are generated between the spray guns 14 and the panel 11. And a negatively charged spray gun 1
4 is atomized with air, and the atomized paint particles 15 are applied to the front surface 1 of the panel 11 along the electrostatic lines of force.
2 and the back surface 13 at the same time.

During this electrostatic coating, the paint particles 15 wrap around and adhere not only to the front 12 and back 13 of the panel 11 but also to the top, bottom, right, left, and right side surfaces 17 of the panel 11, so that the entire surface is coated. Next, after the electrostatic coating described above, forced drying is performed for about one hour to obtain the ALC panel 11 according to this example.

ALC panel 11 according to the above-mentioned embodiment
According to the painting method, the front 12 and back 13 of the panel 11
Since electrostatic coating is applied to each panel, a good coating film 16 having a uniform thickness can be obtained over the entire panel 11 including the upper, lower, left and right side surfaces 16. Therefore, by this coating method, an ALC panel 11 having excellent dimensional stability and durability can be obtained.

Furthermore, when the front side 12 and back side 13 of the ALC panel 11 are electrostatically coated, the top, bottom, left and right sides 17 of the panel 11 are also electrostatically coated at the same time, so there is no need to paint the side faces 17. As a result, painting efficiency can be improved. Furthermore, since most of the paint particles 15 ejected from the spray gun 14 adhere to the surface of the ALC panel 11, high-yield coating is possible.

Note that in the above embodiment, the ALC panel 11
When electrostatically painting the front 12 and back 13 of the , two spray guns 14 were placed on the front 12 side and the back 13 side, respectively, and the painting was carried out at the same time. The 12 side may be electrostatically coated, and then the panel 11 may be turned over and the back side 13 may be electrostatically coated.

Furthermore, in the above embodiment, the flat ALC panel 11 was explained as an example of the inorganic building material.
The shape of the building material is arbitrary; for example, even if the shape is complex, such as a corner panel, electrostatic coating can be applied to the entire surface.

[0017]

[Effects of the Invention] According to the method for coating inorganic building materials according to the present invention, a high yield and a good coating film can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a method of painting an ALC panel according to an embodiment of the present invention.

[Explanation of symbols]

11　ALC panel 12　Front side, which is an inorganic building material 13 Back side 14 Spray gun 15 Paint particles 16 Paint film 17 Side

Claims (1)

[Claims] 1. A method for painting inorganic building materials, which comprises applying electrostatic coating to the front and back surfaces of the inorganic building materials, respectively, and coating the entire surface of the building materials.