JPH0535707B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for sealing vent holes provided in a ceramic body by firing in order to prevent damage during firing in the production of ceramics.

[Conventional technology]

In conventional ceramics, for example, as shown in FIG. 9, a yokote tea utensil a is provided with a hollow lateral hand b for gripping, and a ventilation hole c is provided below the lateral hand b. The ventilation hole c is located at the side of the molded substrate.
This was provided to prevent the Yokote b from being damaged if the hollow part is attached to the base of the tea utensil with it sealed, the pressure of the gas in the hollow part becomes several times higher than normal pressure during firing. It is. Therefore, Yokote b
The ventilation holes c remain even after being glazed and fired.

The present inventor has also applied for a heat-retaining tableware in which an airtight cavity for heat insulation is interposed between the container body and the outer container part in Utility Application No. 144967/1987.

In this heat-retaining tableware, in order to prevent the airtight cavity from being damaged during firing, it is described that a ventilation hole is made in the base material of the outer container part, and that the ventilation hole is sealed with an adhesive or the like after firing.

[Problem to be solved by the invention]

Like the Yokote tea set a mentioned above, there is a ventilation hole c in the Yokote b.
If the tea utensils are left behind, the water that entered during cleaning may remain in the hollow part of the yokote (b) during use, and may leak out while the tea utensils are being handled. For this reason, it is not desirable for ceramic products to have ventilation holes because water tends to remain after cleaning, and the appearance is not good either.

On the other hand, the present inventor has developed the heat retention and cold retention properties of a heat-retaining tableware that has an airtight cavity with sealed ventilation holes and a tableware that has a cavity but communicates with the outside air without sealing the ventilation hole. I compared them and found that the former is much better.

However, in order to commercialize the heat-retaining tableware for which the application has been filed, a process is required to seal the ventilation holes remaining in fired ceramics with adhesive, which is one of the factors that increases the cost of heat-retaining tableware. There is. Moreover, if the adhesive that seals the ventilation holes comes off, the function as a heat-retaining tableware will deteriorate.

In addition, as a manufacturing method for heat-retaining tableware that has already been applied for, there is a method in which the airtight cavity is reduced in pressure when it is in the raw state so that it will not be destroyed by the thermal expansion of the internal gas, but we have experienced that this is time-consuming and often fails. are doing.

An object of the present invention is to provide a method for sealing ventilation holes provided in a base material by firing, in order to eliminate these drawbacks of ceramics having hollow parts or cavities.

[Means to solve the problem]

In order to achieve the purpose of the method for sealing a substrate of the present invention, a hole-sealing glaze is deposited close to and above the ventilation holes provided in the substrate, and the glaze that is melted during firing is applied to the ventilation holes. It is characterized in that it is allowed to solidify after flowing into it.

The features of the present invention will be specifically explained below using examples.

〔Example〕

Example 1 The present invention will be described with reference to a heat-retaining tableware having a double wall structure and an airtight cavity as shown in FIGS. 1 and 2.

The base 1 of the heat-retaining tableware consists of an outer container 2 and an inner container part 3 integrally joined to the outer container 2. A cavity 4 is formed between the two container parts 2 and 3.

If base material 1 is fired as it is, the firing temperature will be 1000℃.
℃, the cavity 4 becomes under high pressure and is damaged during firing, so a vent hole 5 is provided in the base wall of the outer container 2 to prevent the internal pressure of the cavity 4 from becoming too high.

In the present invention, as shown in FIG. 1, in addition to coating the surface of the base 1 with a glaze 6 to be applied by firing, a hole sealing material is provided above the ventilation hole 5. A thick layer of glaze 7 is deposited locally.

The glaze 6 for the vessel surface is for covering almost the entire surface of the base 1 to be fired with a glassy film,
This is a so-called conventional glaze.

On the other hand, the hole sealing glaze 7 is a glaze for sealing the ventilation holes 5.

A preferred example of the present invention is characterized in that the hole-sealing glaze 7 that seals the ventilation holes 5 has a melting point higher than the melting point of the glaze 6 used for coating the surface of the base 1. shall be.

The hole-sealing glaze 7 used has a melting point about 50° C. higher than the glaze 6 for the vessel surface. For example, when the glaze 6 for tableware has a melting point of 900°C, the glaze 7 for sealing the holes has a melting point of 950°C.

In this way, when the pottery glaze 6 and the hole-sealing glaze 7, which have two different melting points, are used for the walls of the base 1 and the ventilation holes 5, the base 1 can be fired to a temperature around 950°C. In this case, low melting point glaze 6
The glaze 7 for sealing the holes, which has a high melting point, melts, but because of its high viscosity, it slowly flows down the wall of the substrate 1 in a granular form, and the glaze 7 for sealing the holes has a high melting point.
stays in place after being sealed.

The amount of the hole-sealing glaze 7 is approximately the same as the internal volume of the vent hole 5, and is sufficient to seal the vent hole 5.

As the hole sealing glaze 7 and the vessel surface glaze 6, commercially available products can be used.

As a preferred example of the present invention, as shown in FIG. It is characterized by having a glaze guide path 8 that extends along the glaze.

Since the hole-sealing glaze 7 has the glaze guide path 8, the high-viscosity glass-like hole-sealing glaze 7 that is melted during firing flows down the glaze guide path 8 and flows into the vent hole 5. , seal it.

As another preferred example of the present invention, as shown in FIG. It is characterized in that it becomes larger toward the wall side of the substrate 1 on which it is deposited.

The ventilation hole 5 is made of a base material 1 on which a hole-sealing glaze 7 is deposited.
Since the wall side is formed with a large diameter and the opposite side is formed with a small diameter, the molten hole sealing glaze 7 can be applied to the ventilation hole 5.
It flows from the large diameter side to facilitate sealing.

Furthermore, as another preferable example of the present invention, as shown in FIGS. 1 and 2, the vent hole 5 is heated so that the molten hole sealing glaze 7 can easily seal the vent hole 5.
It is characterized by making a notch 9 in.

Making the notch 9 in the ventilation hole 5 means that the ventilation hole 5
This increases the inner area of the hole-sealing glaze 7 to make it easier for the molten hole-sealing glaze 7 to infiltrate into the vent hole 5 due to capillary action, and to physically prevent the bonding between the base material 1 and the hole-sealing glaze 7 after firing. Strengthen.

As another preferred example of the present invention, as shown in FIGS. 1 and 2, holes are provided in the vicinity of the ventilation holes 5 so that the molten hole-sealing glaze 7 can easily seal the ventilation holes 5. Partition wall 10 that dams up the flow of sealing glaze 7
It is characterized in that it is provided on one wall of the base material.

In FIG. 1, a partition wall 10 is provided on the back side of the wall of the base 1 so as to prevent the hole-sealing glaze 7 from flowing down through the ventilation holes 5. Therefore, as shown in FIG.
It collects on top of the vent hole 5 and seals it. The hole sealing glaze 7 is used without waste to seal the ventilation holes 5.

In the present invention, for example, as shown in FIG.
After applying a glaze 6 for the vessel surface and locally depositing a glaze 7 for sealing the holes on the ventilation holes 5, the dried product is fired in a kiln. Firing conditions are usually 900 to 1300
℃, and the temperature conditions were determined by setting the maximum firing temperature near the melting point of the hole-sealing glaze 7 used.
It is similar to the conventional firing method.

During firing, the cavity 4 of the substrate 1 communicates with the interior of the kiln through the ventilation hole 5, so the temperature is high but the pressure is normal. Then, the base 1 where the glaze 6 for the vessel surface was melted first.
coated on the outer surface of Next, the hole-sealing glaze 7 having a high melting temperature melts and flows into the vent hole 5 in a granular state, and remains in the vent hole 5 due to capillary action.
Seal.

After firing for a predetermined period of time, the kiln's crater and flue are closed and allowed to cool. The vitreous hole-sealing glaze 7 that seals the air holes 5 of the fired base 1 begins to solidify from a high viscosity state. In this state, the hole-sealing glaze 7 has a strength close to that of the wall of the base 1, and the cavity 4 becomes airtight and under negative pressure. On the other hand, since the interior of the kiln during cooling is communicated with the outside, the temperature is high and the pressure is normal, but since the temperature inside the kiln is approximately constant, the substrate 1 will not be damaged regardless of the cooling inside the kiln. and,
The temperature is lowered to near room temperature and the product 11 of the heat-retaining tableware is taken out from the kiln. The internal pressure of the cavity 4 of this heat-retaining tableware is inversely proportional to the absolute temperature during firing,
For example, the pressure is close to vacuum, such as 1/4 atmosphere.

Example 2 In this example, as shown in FIGS. 4 and 5, ventilation holes 5 are provided at the bottom of the base 1 of the heat-retaining tableware. A hole-sealing glaze 7 is deposited adjacent to the ventilation hole 5. Since the bottom of the base 1 is formed into a concave surface, when the base 1 is fired, the vent holes 5 are sealed with the molten hole sealing glaze 7, and the cavity 4 is depressurized as in Example 1. A product 11 of thermal tableware having the following is obtained.

Further, as shown in FIG. 6, a product 11 of thermal tableware having a cavity 4 sealed with a hole-sealing glaze 7
etc. can also be obtained.

Example 3 The present invention will be explained with reference to the manufacture of Yokote tea utensils, as shown in FIGS. 7 and 8.

In manufacturing the base 1 for tea utensils, when joining the yokote 12 to the main body, the yokote 12 is placed close to the upper side of the ventilation hole 5 where the glaze 7 for hole sealing has been provided in the yokote 12 in advance.
It is deposited in the cavity 4 of.

When the base 1 is fired, as shown in FIG. 8, the ventilation holes 5 are sealed with the molten hole-sealing glaze 7, and a Yokote tea utensil product 11 without any ventilation holes 5 is obtained.

Since no ventilation holes 5 remain in the Yokote tea utensil, there is no risk of water leaking out, and the appearance is good.

〔Effect of the invention〕

According to the method for sealing vents in a substrate of the present invention, the vents provided in the substrate are sealed with a hole-sealing glaze deposited near the vents during firing. Therefore, it is possible to easily and reliably bake tableware for keeping warm or cold, which has a double wall structure and an insulating wall with an airtight cavity, without failure. In tableware for keeping warm and cold, the airtight double-walled cavity has negative pressure, so it has good insulation properties. In addition, since no ventilation holes remain, the product has a good appearance and can be supplied at low cost.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cutaway front views showing the vicinity of the vent hole of the base material before and after firing, respectively, which are sealed according to the present invention, and FIG. 3 shows the vent hole of the base material and the glaze for sealing the hole. The sketch, FIGS. 4 and 5 are cutaway front views of another example of the present invention before and after firing, and FIG. 6 is a cutaway front view of still another example after firing, and FIGS. 7 and 8. 9 is a cutaway front view of another example before and after firing, and FIG. 9 is a bottom view of a conventional ceramic Yokote tea utensil having ventilation holes. DESCRIPTION OF SYMBOLS 1...Base body, 2...Outer container part, 3...Inner container part, 4...Cavity part, 5...Vent hole, 6...Glaze for tableware surface, 7...Glaze for hole sealing, 8... …Glaze guideway,
9... cut, 10... partition wall, 11... product,
a...Yokote tea set, b...Yokote, c...ventilation hole.

Claims (1)

[Scope of Claims] 1. A glaze for sealing the holes is deposited close to and above the ventilation holes provided in the base material, and the glaze melted during firing is allowed to flow into the ventilation holes and then solidified. How to seal vents in substrates. 2. The method according to claim 1, wherein the hole-sealing glaze that seals the ventilation holes has a melting point higher than the melting point of the glaze for vessel surfaces used to cover the surface of the base. How to seal vents in substrates. 3. A patent claim characterized in that the molten pore-sealing glaze has a glaze guide path extending toward the vent so that the molten pore-sealing glaze is easily guided to the vent along the wall of the base material. A method for sealing vents in a substrate according to item 1. 4. Claim 1, characterized in that the shape of the vent hole is enlarged toward the base wall on which the hole-sealing glaze is deposited so that the molten hole-sealing glaze is easily guided into the vent hole. A method for sealing vents in a substrate according to item 1 or 3. 5. Any one of claims 1, 3, and 4, characterized in that a notch is made in the ventilation hole so that the molten hole-sealing glaze can easily seal the ventilation hole. Method for sealing vents in substrates as described in section. 6. A patent claim characterized in that a partition portion for damming the flow of the hole-sealing glaze is provided on the base wall in proximity to the air hole so that the molten hole-sealing glaze can easily seal the air hole. A method for sealing air holes in a substrate according to any one of items 1, 3, 4, and 5.