JPH0676267B2 - Manufacturing method of decorated baked products - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fired product such as a tile having a decorative layer on the surface of the substrate, and more specifically, a reducing gas is directly blown to the decorative layer having a reducing coloring component on the surface of the substrate. To develop the reduction coloring component,
The present invention relates to a decorative fired product formed by producing a decorative layer and a method for manufacturing the same.

(Prior Art) Ceramic tiles and other fired products can be obtained by firing them in various kilns as they are, or by firing with a glaze on the surface.

The color of the fired product obtained in this manner changes subtly depending on the atmosphere during firing, and particularly when firing in a reducing atmosphere, sometimes a deeply tasty color / pattern is obtained.

For this reason, conventionally, a reducing atmosphere is created during firing in the firing process in a kiln, and the surface is subjected to reduction treatment simultaneously with firing.

This reducing atmosphere is generally created by making the air-fuel ratio of the burner lower than that during normal firing. However, in reducing firing in such a reducing atmosphere, it is described below that the reducing conditions are uniformly maintained and controlled. It is extremely difficult as mentioned above.

Reduction of the calcined product is performed by removing oxygen in the calcined product. The reducing gas used to reduce the calcined product is
Fuel gas containing carbon and hydrogen (eg propane gas)
When using, CO, H decomposed and produced by burner flame
A mixed gas of _two gases, of which CO gas has a large amount of C in the gas and is relatively stable in the high temperature range of 1200 ° C. or higher, but is unstable if the conditions are not satisfied, and even a little. If O ₂ is present, it becomes CO ₂ , and as the temperature decreases, it decomposes into C and CO ₂ due to the carbon deposition reaction, and it does not function as a reducing gas.

When a reducing atmosphere is created in the kiln to reduce the calcined product, it is extremely difficult to completely shut off the reducing atmosphere from the external atmosphere such as the atmosphere of the preceding and following processes, and the reduction suitable for the reduction of the calcined product. It is difficult to secure the atmosphere.

The temperature of the fired product during the reduction treatment is also an important factor,
It is extremely difficult to reduce the temperature of the fired product evenly in such an atmosphere while adjusting the temperature. For this reason, in the conventional method, it is not possible to stably produce a product having a uniform and desired reduced color.

Therefore, the inventors of the present invention have devised a method in which the reducing gas ejected from the ejection holes is directly blown to the fired product in a heated state so that the decorative layer as the surface layer is colored in a reducing color.

According to this method, unlike the reduction in the reducing atmosphere, the reduction treatment is performed in a state where the surface of the fired product is surrounded by the reducing gas blown out from the ejection holes at a constant flow rate. That is, since the reduction is performed in a state in which the invasion of the external atmosphere is blocked by the reducing gas flow, it becomes easy to maintain and control the reducing conditions uniformly, and thereby a stable reducing color can be obtained.

(Problems to be solved by the invention) By the way, most of the color-forming components in the decorative layer are transition metal elements, and when oxidized and baked, the color-forming components are in an oxidized state to develop a color unique to that state, In addition, when reduced and baked, it becomes a reduced state and develops a unique color. The reduced color is often deep and beautiful.

On the other hand, however, these coloring components are inferior in chemical resistance in the reduced state, and therefore, while the surface is washed with a detergent, the surface becomes cloudy, discolored or brown. Therefore, in the case of a fired product such as a tile formed by reducing and coloring a decorative layer such as a glaze on the surface, there is a disadvantage that its use is limited despite having a beautiful color and luster. For example, if CuO is included in the glaze as a coloring component and this is subjected to a reduction treatment, Cu crystals precipitate and a metallic metallic beautiful glaze layer is obtained, but these metal crystals come into contact with chemicals. It is eluted and lost from the glaze.
For this reason, the fired product, which initially had a beautiful metallic copper color, was washed with solvent many times, and the original beautiful color,
The luster is lost.

As a means for solving this, it is conceivable to form a decorative layer by reduction coloring on the surface of the base material of the fired product and then form a translucent chemical resistant protective film on the surface.

In this way, by the action of the translucent chemical-resistant protective film on the upper side of the decorative layer having a reducing color, even if the fired product comes into contact with various chemicals, the coloring component of the decorative layer is not attacked, and therefore the original You can hold beautiful colors forever. Therefore, such a baked product can be used for various purposes.

By the way, when forming a translucent chemical resistant protective film on the upper side of the decorative layer, generally, after forming the decorative layer and reducing and coloring it, a chemical resistant protective film is further formed on the upper side thereof. It is a general method to do so, but if done in this way, the step of forming the decorative layer, the step of reducing and developing the decorative layer, and the step of forming the protective film on the upper side of the decorative layer are performed separately. Manufacturing process becomes complicated and the manufacturing cost becomes high.

(Means for Solving the Problem) The invention of the present application has been made for the purpose of solving such a problem, and its gist is to provide uncolored decoration containing a reducing color-forming component on the surface of the substrate. In the method for producing a decorative fired product in which a layer is formed and subjected to a reduction treatment to reduce the coloring of the decorative layer, a translucent chemical resistant protective film is formed on the surface of the decorative layer before the reduction coloring. A reducing gas is directly blown to the surface of the protective film in a state in which the formed and baked product is heated to reduce and develop the coloring component of the decorative layer.

(Operation and effect of the invention) In this method for producing a decorated fired product, a reducing gas is sprayed onto the decorative layer on the surface of the fired product to cause the reducing color-forming component to develop a reducing color. A protective film is formed on the surface of the decorative layer, and a reducing gas is blown onto the baked product in a heated state (preferably from a close distance of 15 to 80 mm) to carry out a reduction treatment, thereby reducing the color of the decorative layer. The feature is that it is colored.

Therefore, in the present invention, for example, a first glaze layer is formed as a decorative layer containing a reducing coloring component on the surface of the base material of the tile, and a translucent second glaze layer is formed as a chemical resistance protective film on the surface. In the case of applying these glazes to the surface of the tile base in two layers in advance and firing it in a firing furnace, at that time, a reducing gas is ejected from the ejection holes at predetermined locations inside the oven and sprayed onto the tile surface, By reducing the color of the lower glaze layer to be the decorative layer, the formation of the decorative layer, the formation of the chemical resistant protective film, and the reduction color of the decorative layer can be performed all at once in substantially the same step. The manufacturing cost can be reduced, and the productivity can be improved.

The present inventor initially applied a glaze layer having a reducing coloring component to the two layers in advance on the surface of the tile substrate and spraying a reducing gas in parallel with firing, and the glaze in the upper layer melts to give the belly. I thought that it may form and block the lower glaze layer and not reduce the color down to the lower glaze layer, but by experiment, about reducing color not only to the upper glaze layer but also to the deep part of the lower glaze layer I got the knowledge. Although the reason for this is not clearly understood, one possibility is that the reducing gas acts on the decorative layer through the fine micropores in the base material. However, this has not been proven. The present invention has been completed based on these findings.

The reduction treatment is conveniently performed concurrently with the firing of the fired product or immediately after the firing, but this reduction treatment can be performed independently of the firing as a treatment step separate from the firing. is there.

The present invention can also be applied to fired products of various forms and materials other than the above tiles.

Further, a transparent or translucent glaze is preferable as the chemical-resistant protective film, but the material and the form thereof are not particularly limited, and another one may be used.

(Example) Next, in order to further clarify the characteristics of the present invention, an example will be described in detail below.

As shown in FIG. 1, a glaze (lower glaze) 10 having a reducing coloring component having the composition shown in Table 1 is blended and formed on the surface of the tile base 12 as a decorative layer, and further on it. Then, a glaze (upper glaze) 14 having the composition shown in Table 2 was applied as a chemical-resistant protective film forming material. The lower glaze and the upper glaze were applied in the amounts shown in Table 3, respectively.

Then the tiles with these glazes were baked at a maximum firing temperature of 1180
Firing was performed under conditions of ℃ and firing time of 30 minutes. Immediately after the firing, as shown in FIG. 2B, a reducing flame (reducing gas) generated by the reducing burner 16 was jetted and sprayed onto the tile surface, whereby the lower glaze 10 was reduced and colored (C). .

The conditions of the reducing gas blowing process are shown in Table 4.

As a result, as shown in the reference photograph (a), a tile having a glazed surface with a beautiful metallic tone based on Cu precipitation was obtained. For comparison, the reference photograph (b) shows the surface condition of the fired tile when the upper glaze 14 was not applied.

Next, this fired tile was subjected to a chemical resistance test under the conditions shown in Table 5. At this time, in order to investigate the effect of the upper glaze 14, the same test was performed on the tiles without the upper glaze 14. The results are shown in the reference photographs (C) and (D) ((C) the top glaze 14 was applied, and (D) the top glaze was not applied).

As a result of this experiment, as is clear from the comparison of the reference photos (a) and (b), the one with the upper glaze 14 has a beautiful metallic glaze surface like the one without the upper glaze, and Regarding the chemical resistance, as is clear from the comparison of the reference photographs (C) and (D), it was confirmed that the product with the upper glaze 14 was significantly superior to the product without this.

Although the embodiments of the present invention have been described in detail above, the present invention can be configured and implemented in variously modified forms based on the knowledge of those skilled in the art without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodied state of a decorative tile and a surface reduction treatment method thereof according to an embodiment of the present invention. 10: Lower glaze 12: Tile base 14: Upper glaze 16: Reduction burner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Iwahashi, 3-6, Koiemotocho, Tokoname City, Aichi Prefecture Inax Co., Ltd. Nippon Steel Co., Ltd., Equipment Technology Headquarters (72) Inventor Kazumi Kurayoshi 1-1-1, Edamitsu, Hachimanto-ku, Kitakyushu, Kitakyushu, Fukuoka (72) Inventor, Akio Ishii, Kitakyushu, Fukuoka Prefecture 1-1-1 Emitsu, Hachimanto-ku, Yokohama-shi, Nippon Steel Co., Ltd. Equipment Engineering Headquarters (56) Reference JP-A-63-236635 (JP, A)

Claims (1)

[Claims] 1. A method for producing a decorative fired product, comprising forming an uncolored decorative layer containing a reducing color-forming component on the surface of a base material, subjecting this to a reduction treatment, and reducing the colored color of the decorative layer. A translucent, chemical-resistant protective film is formed on the surface of the decorative layer before reduction coloring, and a reducing gas is directly blown to the surface of the protective film in a state where the baked product is heated to reduce the coloring component of the decorative layer. A method for producing a decorated fired product, which is characterized by coloring.