JPH0422872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing a glazed cementitious base material having sufficient gloss and a glass layer formed on its surface with sufficient adhesion strength.

Prior art and problems Cementitious base materials, such as concrete plates,
Attempts have been made to form coating films on GRC boards, asbestos cement boards, and calcium silicate boards to improve weather resistance and give them a beautiful appearance. Methods such as applying and firing to obtain a glazed surface have been tried. However, the method of applying organic paint is insufficient in terms of weather resistance since the cementitious base material is mainly used for the exterior walls of buildings.
In addition, from the standpoint of fire prevention, heat resistance is low and it is difficult to say that it is safe.

Next, inorganic paints have been commercialized, but there are many problems that need to be solved in terms of film stability, heat resistance, stain resistance, etc., and there are no durable ones for surface finishing of building materials. Not obtained.

On the other hand, attempts have been made to form a glass layer by applying a glaze onto a cementitious base material and firing it, and a weather-resistant product has been obtained. Therefore, a huge amount of thermal energy is required, which is unfavorable in terms of energy saving and cost saving, and the cementitious base material deteriorates due to heating. Further, when the base material deteriorates further, the glass layer peels off. Currently, it cannot be used for cement base materials containing fiber materials, which are subject to severe thermal deterioration, such as GRC boards containing glass fibers and asbestos cement boards containing asbestos.

To solve these problems, heat sensitive e.g. 500
As a method for forming a glass layer on a cementitious base material that deteriorates thermally at °C, only the surface layer of the cementitious base material is locally heated with a gas burner to melt the surface of the base material itself, or Attempts to obtain a glass layer by melting glass raw materials applied to the surface of a base material, or attempts to melt glaze particles forming a glass layer in the flame and attach them directly to the base material. has been carried out.

However, in the above method, the flame is unstable and it is difficult to control the flame condition, making it difficult to obtain a glass layer that is uniform in thickness and color.
Therefore, since the glaze melts unevenly, peeling between the glass layer and the base material is likely to occur. Adjusting the color of the glass layer is also difficult because the soot adhesion caused by the flame and the oxidation conditions within the flame change the color of the glass layer. Furthermore, the surface of the base material also undergoes thermal deterioration due to heat transfer.

Furthermore, in the case of 2, the glaze particles were exposed to high temperatures in the flame and were decomposed, and blocking of the particles occurred, making it impossible to obtain a uniform glass layer. Furthermore, there are problems of peeling and thermal deterioration similar to those mentioned above.

The above problems are mainly due to (1) the nature of the cementitious base material which is susceptible to thermal deterioration, and (2) the nature of glazes which generally have a high melting point and can become quite viscous if melted insufficiently. This is due to the fact that Conventionally, it has been extremely difficult to adhere a glass layer to a substrate while simultaneously satisfying both of these contradictory properties (1) of the substrate and properties (2) of the glaze.

Solution According to the present invention, a glaze is applied to a cementitious base material to form a uniform glaze coating film, only the glaze coating film is melted in a short time by plasma flame, and the glass layer is attached to the cementitious base material. We succeeded in solving the above problem by using a method of adhering to the material. Note that the above-mentioned uniform glaze coating means that the applied glaze is even and the thickness and color of the coating are uniform.

The inventor applies a relatively moving plasma flame to a glaze coating on a substrate while maintaining a substantially constant distance to melt the glaze coating without thermally degrading the substrate. It has been unexpectedly discovered that a glass layer can be uniformly adhered to the substrate by using the above method.

This unexpected effect is caused by, for example: (a) Since the plasma flame has a very high temperature, the glaze is sufficiently melted almost instantaneously by the relative movement of the plasma flame, so that the heating of the substrate is (b) Furthermore, since the plasma flame continuously moves over the glaze coating film of the base material and sufficiently melts the glaze coating film uniformly and continuously, pinhole in glass layer,
This is thought to be due to the fact that the occurrence of cracks, etc. is avoided.

SUMMARY OF THE INVENTION The method of the present invention is advantageously applied to cementitious substrates which normally have a substantially planar glaze coating, but which have a curved glaze coating without abrupt changes in shape. It can also be applied to base materials. That is, in the latter case, if the change in the distance between the glaze coating and the plasma generator (for example, plasma gun) is within about 5%, it can be carried out in the same manner as in the case of a flat glaze coating. .

If the distance between the two changes by about 5% or more, move the position of the plasma gun in the direction of the distance according to the change in the curved surface so that the distance from the curved surface of the glaze coating remains almost constant. It is preferable to apply a plasma flame. In addition, when applying a glaze to the surface of a rod-shaped base material such as a cylindrical or cylindrical shape, the plasma flame can be applied, for example, by rotating and moving the glazed rod-shaped base material.

The apparatus for use in the present invention consists essentially of at least one plasma gun and a support for holding the plasma gun and the glazed substrate, respectively;
In order to uniformly apply the plasma flame to the entire glaze coating, the apparatus is characterized by comprising means for moving the gun support and/or the substrate support. For example, a conveying machine that moves a glazed substrate by fixing a plurality of plasma guns arranged at predetermined intervals and maintaining a fixed distance from the guns in a direction substantially perpendicular to the arrangement of the guns. An example of a device having the following configuration is illustrated. An example is also exemplified in which one plasma gun is moved back and forth in a direction perpendicular to the transport method instead of the plurality of guns. Furthermore, in the case of a base material having a curved glaze coating as described above, the position of the plasma gun can be changed in the direction of the distance between the two in accordance with changes in the curved surface. Note that each moving means in each of the above embodiments can be automatically controlled by electronics. These control means can be implemented based on common technical knowledge of, for example, automatic machine tools, so a detailed description of control by electronics will be omitted.

In order to improve these points, the present invention forms a uniform glaze coating film on a cementitious base material by spraying or covering with a suspension of glaze particles, so-called glaze slurry, and then forms a stable glaze coating film on a cementitious base material. The glaze coating on the surface of the substrate was heated for a short time using a plasma flame capable of heating.

The reason why plasma flame was used in the present invention is that the thickness and color of the glass layer can be controlled better with plasma flame than with ordinary flame, and there is no need to heat the inside of the cementitious base material. This is because it is sufficient to form a glass layer on the surface of the base material instead of melting the glaze coating film by heating with a plasma flame for a short time to form a glass layer.

As a result, it is possible to obtain a glossy glass layer which has a uniform thickness, which has been difficult to obtain up to now, has no pinholes or cracks, and has excellent adhesion strength.

DETAILED DESCRIPTION OF THE INVENTION The term "cementitious base material" as used in the present invention means a base material made of a molded article containing a hydraulic inorganic cement material as an essential component, and typically the base material is substantially flat. It has a shaped surface to be glazed, but the surface may be curved. The above-mentioned inorganic cement materials include, for example, Portland cement, alumina cement, blast furnace cement, jet cement, slag cement, gypsum cement, and the like.

The plasma flame used in the present invention mainly includes:
A high-temperature, high-speed plasma jet formed by ionizing an inert gas such as nitrogen gas, argon gas, or neon gas. Furthermore, hydrogen, air, etc. may be used in addition to the inert gas, if necessary.

The energy range of the plasma flame applied to the glaze coating is not particularly limited, but all commercially available plasma guns can be advantageously applied.

The area to which the plasma flame is applied at a moment varies depending on the energy generated by the plasma, but it is usually applied in the form of a circular surface with a diameter of about 1 cm to 10 cm. Further, the distance between the plasma gun and the glaze coating is usually between about 5 cm and 30 cm and varies mainly depending on the melting temperature of the glaze.

Example 1 A suspension was prepared by mixing 100 parts by weight of glaze particles (blue enamel powder, trade name: V2804 manufactured by Blythe Co., Ltd.), 50 parts by weight of ethyl alcohol, and 150 parts by weight of water, and this was made into a suspension using an air spray gun. It was sprayed onto a JIS standard asbestos cement substrate (300 x 300 x 3 mm thick) held vertically. The amount of glaze applied is about 9 grams. It was left in the air for 5 minutes.
The following plasma gun (Meteco type 9MB)
Apply plasma flame horizontally to the surface of the substrate using
Scanning was performed at a speed of mm/sec, and only the glaze coating was melted while descending vertically by 3 cm with each scan.
Application time required approximately 2 minutes. The plasma generation conditions were 440 A, 75 V, N ₂ flow rate: 2.83 m ³ /hour, H ₂ flow rate: 0.57 m ³ /hour, and the distance between the plasma gun and the substrate was 17 cm. Approximately one operation above
A glass layer with a film thickness of 30 μm was obtained. It was confirmed that a glass layer having a desired thickness could be obtained by repeating the above operations as necessary. This glass layer was glossy, free of pinholes and cracks, and had good adhesion. Moreover, the substrate was not damaged.

Example 2 A cement concrete substrate (300 x 300 x 10 mm thick) was used in place of the asbestos cement substrate of Example 1. The rest was carried out in the same manner as in Example 1.

As a result, a glossy glass layer with good adhesion was obtained. Moreover, the cement concrete base material was not destroyed.

Effects By using plasma flame, a uniform glass layer can be obtained. As a result, unnecessary stress is not generated on the surface of the cementitious base material.
No pinholes or cracks occur, and adhesion strength is improved.

Since the glass layer is homogeneous, a glass layer without uneven gloss can be obtained.

By using plasma flame, it is possible to melt only the glaze coating on the surface of the cementitious base material, so it is possible to melt only the glaze coating on the surface of the cementitious base material, so it is possible to melt only the glaze coating on the surface of the cementitious base material. ) can also be glazed.

Since only the glaze coating film on the base material is heated and the entire base material is not heated, the energy saving effect is also large.

Claims (1)

[Claims] 1 Applying glaze on the cementitious base material, moving the base material and/or the plasma generator relatively to melt only the glaze coating film by plasma flame, and bringing the glass layer into close contact with the cementitious base material. A method for producing a glazed cementitious base material, characterized in that: