JPH0510308B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for sealing an air outflow hole formed in a ceramic double structure container.

(Prior Technology) Traditionally, ceramic containers such as coffee cups, mugs, teacups, and other ceramic containers have been kept warm.
Some have a double layered structure to enhance their cooling function. When manufacturing this type of double-layered ceramic container, the inner and outer walls of the container are usually molded by casting or using a potter's wheel, and then combined and bonded with slurry. Air outflow holes must be left open. This allows the expanded air to escape to the outside in order to prevent the container from being destroyed by the expansion of the air in the void surrounded by the double walls when firing at high temperatures after molding and drying. It's for a reason.

As described above, air outflow holes are essential in manufacturing double-layered ceramic containers.

By the way, such double-walled ceramic containers have better heat and cold retention functions than single-walled containers, but on the other hand, when washing the container, water gets into the double wall through the air outlet holes, making cleaning difficult. Even after wiping off the water droplets on the surface of the container, in case of unexpected
Water remaining inside the heavy wall may drip to the outside, so care must be taken when cleaning, and air outflow holes reduce the commercial value of the double-walled container.

Conventionally, therefore, in the manufacture of this type of double-layered container, the air outflow hole has been plugged with an adhesive such as epoxy resin after the overlay has been baked.

(Problems to be Solved by the Invention) With the above-mentioned method of sealing the air outflow hole with adhesive, there is a considerable temperature difference between when the container is filled with hot drinks and when it is not in use, so the method is repeated over a long period of time. The disadvantage is that the adhesive peels off during use.

Furthermore, the sealing method using adhesive is carried out after the overglaze printing operation, which is the final step in ordinary ceramic manufacturing, but the increase in the number of steps results in an increase in manufacturing costs.

In view of these drawbacks, the present invention provides a method for sealing the air outlet hole of a ceramic double-layered container, which allows the air outlet hole to remain sealed even during long-term use and does not require any special process. It is about providing.

(Means for Solving the Problems) The present invention provides a method in which a glaze made by mixing ceramic coarse particles with a medium for overglazes is perforated into a ceramic double-structure container during overglaze painting. The glaze is applied to the air outflow hole, and the ceramic double structure container is overglazed with the outflow hole facing upward, thereby melting the glaze and sealing the air outflow hole. That is.

(Example) As shown in Fig. 1, a ceramic mug 1 with a double structure is composed of an outer wall part 2 and an inner wall part 3 which are molded separately in advance. A heavy-duty mug is made. During molding of the outer wall portion 2, air outflow holes 4 are bored.

The mug then undergoes the drying, glazing, and firing processes, and then the overlay painting process.

The work of overpainting is done by hand, using rubber stamps, spraying, transfer, etc. for each individual product, but according to the present invention, during this overpainting process, the second As shown in the figure, air outlet hole 4
A glaze 6 made by mixing coarse ceramic particles 5 with a medium for top paint is applied using a brush.

In this example, 30.8% by weight of lead oxide (PbO) and sodium oxide (Na ₂ O) were used as the medium for the top paint.
A frit with a composition of 28.5% by weight, 21.9% by weight of boron oxide (B ₂ O ₃ ), and 18.8% by weight of silicic acid (SiO ₂ ) was used. Coarsely crushed particles with a particle size of around 0.5 mm were used. Coarse ceramic particles were mixed into this frit, and 15% of tin oxide (SnO ₂ ) was added as a color base to 75% of the frit. The glaze prepared in this way can be used as a white glaze paint.

After this glaze is melted with a viscous liquid and applied to the air outlet holes 4, the painting is fired at a low temperature of approximately 750° C. with the air outlet holes 4 facing upward. As the temperature within the void 7 surrounded by the outer and inner walls gradually rises, the air within the void 7 expands, spreads the applied glaze 6, and flows out to the outside, resulting in a reduced pressure state. Furthermore, when the temperature within the void increases and reaches a temperature equal to the temperature inside the kiln, the air within the void no longer flows out to the outside.
The applied glaze 6 is continued to be baked at this temperature until it is completely melted. The melted glaze has fluidity and if left as it is, it would drip into the voids 7 through the air outflow holes 4. However, according to the present invention, since coarse ceramic particles 5 are mixed in the glaze 6, the voids 7 The air does not drip into the air outflow hole 4, but instead accumulates inside the air outflow hole 4 and blocks the air outflow hole 4. In this embodiment, the air outflow hole 6 is formed into a funnel shape in order to make it easier for the glaze 6 to accumulate inside the air outflow hole 6. When cooled after firing, the glaze 6 becomes glassy and adheres closely to the surface of the outer wall portion 2, and the inside of the gap 7 is sealed under reduced pressure.

In this example, the composition described above was used as a medium for the overpaint, and tin oxide was added as a pigment to prepare a white overpaint. This is because the sealed portion of the air outflow hole becomes less noticeable.
The composition of the frit is not limited to this example, and other compositions may be used as long as it is a medium for overpainting that melts at low temperatures. If it is applied to the air outflow hole during printing, the air outflow hole can be sealed. Further, the particle size of the ceramic should be appropriately selected depending on the diameter of the air outflow hole so that the molten glaze accumulates in the air outflow hole, and is not limited to the particle size described in the examples.

(Effects of the Invention) According to the present invention, a glaze for blocking the air outflow holes is applied at the same time as the overglaze is applied, and this glaze melts at the firing temperature during the overglaze firing. If you print the image, the air outflow hole will be closed naturally, and the air outflow hole formed in the double-layered ceramic container can be closed without the need for any special process, thereby reducing the increase in manufacturing costs. It never comes.

In addition, the glaze for sealing the air outflow holes does not require any special raw materials or composition; instead, it is made by crushing ceramic waste such as bricks and fragments of saggers into the frit used when mixing the overglaze. It is only necessary to mix the coarse particles granulated by the process, and it can be easily procured.

Furthermore, since the air outlet holes are sealed with glaze, it will not peel off even after repeated use over a long period of time.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of a ceramic mug with a double structure, and FIGS. 2 and 3 are partially enlarged sectional views thereof. 1...Double structure ceramic mug, 2...Outer wall part, 3...Inner wall part, 4...Air outflow hole, 5...Coarse particles, 6...Glaze, 7...Void.

Claims (1)

[Claims] 1. During overglaze painting, a glaze made by mixing coarse ceramic particles with a medium for overglazing is applied to an air outlet hole drilled in a double-layered ceramic container, and the air outlet hole is opened upward. Sealing the air outlet hole of a ceramic double structure container, characterized in that the ceramic double structure container is overglazed in a state facing toward the surface, thereby melting the glaze and sealing the air outlet hole. Method.