JPS63311910A - Heat accumulation type ceramic tableware - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention ``Object of the Invention'' The present invention relates to a heat storage type ceramic tableware, which exhibits a heat or cold retention function when serving meals, etc., allows eating and drinking under favorable temperature conditions, and has ensured strength. The aim is to provide quality tableware.

(Industrial field of use) Ceramic tableware for storing various types of food for eating and drinking.

(Conventional technology) Tableware is an essential appliance in our daily lives, and various materials are used for such tableware, but ceramic ones have a unique texture, solidity, and style. It is well known that tableware has a value that cannot be found in tableware made of other synthetic resins, and it has been used in various ways since ancient times.

In other words, it is a vessel made of china clay, etc., with a glazed layer formed on the base surface, and there are various shapes and types such as a dish shape, a bowl shape, a plate shape, and a teacup shape. is generally dense in the thickness direction.

In addition, when heat retention is particularly required for general items such as those that are hollow or double-walled in the wall thickness direction, and laminated tableware that uses heat insulating materials, for example, Japanese Patent Laid-Open No. 61-215246 discloses Publication No. 60-318
This is proposed in Publication No. 77, etc.

(Problems to be Solved by the Invention) However, in the conventional ceramic tableware as described above, the heat-retaining effect is not necessarily favorable.

In other words, the temperature of the food and drink stored or served on such tableware is suitable for eating and drinking, which is the reason why you can eat and drink carefully prepared food deliciously and comfortably. When serving food that has been heated and baked in tableware as is, party dishes,
When preparing meals for a large number of people at a school or hospital, etc., or when the food is consumed after reaching the customer in a delivery order, etc., the food and drink stored during the time elapsed from cooking to being served and being consumed. Depending on the food, for example, 50-60℃ for high-temperature cooking, 5-10℃ for low-temperature cooking.
It is difficult to ensure the optimum temperature for expiration, such as around ℃.

Of course, when eating and drinking in other households, restaurants, etc., it is not always easy to maintain appropriate temperature conditions that are favorable for taste until the end of the meal, depending on the type of food and the season.

For this reason, some hollow or double-walled tableware, or laminated tableware using heat-insulating materials, which have been proposed, require complicated and sophisticated technology to manufacture, and are inevitably expensive. I don't get it. In addition, such hollow or laminated type items are generally inferior in strength, require careful handling, and are used in large quantities at parties, school lunches, etc. as mentioned above. transporting tableware,
Under handling conditions such as washing, wiping, and drying, the possibility of damage is extremely high.

"Structure of the invention" (Means for solving the problem) 30 to 70 wt% of either or both of alumina and zirconia raw materials are blended into a ceramic material,
Thermal conductivity is 0.0 on the base surface of the vessel whose specific gravity is 2.6 or more.
022cal/am ・A heat-storage type ceramic tableware characterized by having a glaze-baked layer having a thickness of 0.5 or more and having a thickness of 0.5 or more and covering at least the open surface side.

(Function) By blending 30% or more by weight (hereinafter simply referred to as %) of alumina or zirconia raw materials into ceramic materials, strength is ensured in the fired ceramic body, and its specific gravity is 2.6 or more. This increases the heat capacity of the substrate and provides heat storage properties. In addition, by keeping the content of either or both of these alumina and zirconia materials at 70% or less, low-temperature sinterability and glaze spreadability are ensured, and 0.5 tm
It is possible to stably form a glaze-baked layer having the above thickness, and avoid disadvantages in equipment and cost due to relatively high firing temperatures. The thermal conductivity of the glaze baking layer is 0.022 cal! /cIII・℃・sec
By setting the following, it is possible to reduce the amount of heat radiated from the surface of the substrate under conditions where the heat capacity of the substrate body is high, and it is possible to achieve the desired heat/cool retention time.

Furthermore, by setting the thickness of this baked glaze layer to 0.5 f1 or more, the above-mentioned properties, particularly low thermal conductivity, of the baked glaze layer can be appropriately obtained. A preferable lower limit is 0.7 cranes.

The upper limit of the thickness of the glaze baking layer is 1.8 fl or less, especially 1.5 fl or less, and if the glaze baking layer is thicker than this limit, the heat storage time required to preheat and precool the tableware itself to a predetermined temperature will increase. This is not desirable because it takes a long time and is not practical, and cracks are likely to occur in the glaze baking layer due to the difference in thermal expansion with the base material.

By setting the upper limit to this level, those disadvantages can be eliminated.
□No products can be made.

(Example) To further explain the present invention as described above, clay, which has been commonly used as a ceramic material,
Materials such as feldspar, pottery stone, silica stone, kaolin, and sericite can be widely used.

In addition, as raw materials for one or both of alumina and zirconia for such ceramic materials, alumina and zircon sand (SiO'z・ZrO□) generated by the Bayer process in the aluminum manufacturing process are preferable. These substances are added singly or in combination in an amount of 30 to 70%.

By blending 30% or more of alumina into a ceramic material, a specific gravity of at least 2.6 or more can be obtained,
When 30% of zirconia is blended, the specific gravity becomes 3.5 or more. Also, if more than 70% alumina is blended, the specific gravity will be 3.4.
~3.6, and when 70% zirconia is blended, the specific gravity will be about 4.9 to 5.3, and when these are mixed, it will have a specific gravity between them depending on the mixing ratio. Therefore, the specific gravity of the substrate body in the present invention is 2.6 to 5.3, preferably 2.8 to 5.
．． It is obtained as having an average specific gravity of 3.

The overall composition according to specific formulation examples is typically as follows.

5in2: 0.6-1.2 mol tltOs: 0.2-0.5 mol Zr0t: 0.2-0.5 mol IhO+RO:
0.01 to 0.3 mol (R is Nas Cas
(K% Ba5Pbs Mg5Zn, etc.) The glaze is compatible with the above-mentioned material properties and has a thermal conductivity of 0.0.
022 Cal / cm ・If it is less than "C-sec", it may be related to the decoration etc., and an appropriate value will be adopted, but preferably 0.0008~O,0O18Ca 1
2/mouth・℃・sec. The raw materials for this glaze are:
Glass lift, feldspar, clay, limestone, talc, pottery stone,
Examples include alumina, zirconia, silica, magnesite, kaolin, bone ash, etc. Sodium silicate is used as a dispersing agent in water, and sodium methacrylate and popal are used as spreading agents on the substrate. Here are some typical examples of formulations:
It is as shown in the table.

Regarding the concentration of the glaze slurry in Table 1, the film thickness per coat can be increased by increasing the concentration, but the usual method may be used.

For example, the coating can be suitably applied with a glaze in a range of 40 to 70% and water in a range of 60 to 30%, and any coating method such as dipping, spray coating, or brush coating may be used. Regarding the coating, it is preferable to completely coat the supporting seat part, which is generally formed in this type of tableware, without leaving the base material exposed.

In production, alumina and zirconia raw materials are added and mixed with ceramic materials, water is added and kneaded, and the resulting clay is molded into tableware bodies. After drying the obtained product, 60
Bisque firing is carried out in an oxidizing atmosphere at 0 to 900° C. for about 24 hours, and a glaze mixed with water is applied to the bisque fired base. For example, glaze-coated items are pre-dried using an infrared dryer, then heated to 1100~1380
Fired at ℃ for about 24 hours, then painted.
The product is made by painting and firing at 50 to 1000°C. It is well known that there are two types of glazes: overglaze and overglaze, and the glazing process is quite different.

Some examples of the tableware of the present invention that can be obtained are shown in Figures 1 to 5, and there are plate-shaped, bowl-shaped, pot-shaped, cup-shaped, sake bottle-shaped, etc. It may also be implemented as a double-walled type (a bowl-shaped type is shown as a representative example, but the same applies to other types) as shown in Fig. 6, and in any case, the above-mentioned A glaze baking layer 2 is applied. The baked glaze layer 2 according to the present invention is formed on the entire inner and outer surfaces as shown in FIG. Furthermore, as shown in FIG. 3, the glaze baking layer 2 according to the present invention can be formed on the outer surface of a conventional ordinary glaze baking layer 3 formed on the entire surface.

To explain specific manufacturing examples and comparative examples,
It is as follows.

Production Example 1 A rice bowl-shaped base container having a wall thickness of 7 nm and an internal volume of 180 cJ according to the present invention and Comparative Examples A, B and C were prepared. That is, the compositions of Comparative Examples A and B, which are production examples of the present invention using alumina, silica, feldspar, titanium oxide, limestone, etc. by the Bayer process, are as shown in Table 2 below, and Comparative Example C
is a melamine resin product.

Table 2 (%) The composition of the glaze applied to each surface of the above-mentioned base container is feldspar, silica, zircon, sand, and beryllia, and the slurry concentration is 60% as shown in Table 3 below. The one was adopted.

Table 3 (Mole) Specific gravity and film thickness of the glaze baking layer for the product of the present invention and each comparative example (comparative example C is a melamine resin molded product as described above) and removal after being held at 92°C for 2 hours in a disposer. The temperature drop state and intensity due to heat radiation in the substance when left at room temperature in a windless state are as shown in Table 4 below.

That is, according to Table 4, it can be seen that the product according to the present invention has heat retention properties that are approximately the same as the melamine resin product of Comparative Example C, and this can be said to be an impressive result for such a ceramic product.

However, the temperature at which general grilled and boiled dishes are considered to be best for eating is 60 to 70°C, and Comparative Examples A and H have a temperature of 1.
It was confirmed that while the temperature drops out of the proper temperature state after about 0 minutes, the device according to the present invention can maintain the proper temperature state even after twice that time.

It is natural that having the above-mentioned heat-retaining properties will also have the same effect on cold storage. For example, if you put soup at 90°C and keep it at 50-60°C, it will take at least 20-40 minutes. Also, experimentally, the time that a 5°C beverage can be kept at 10°C is 40 to 90 minutes, and this cold retention time is generally more than twice that of conventional ceramic tableware.

Production example 2 40 parts of alumina, 20 parts of feldspar, 3 parts of clay by Bayer method
0 parts, 10 parts of kaolin, and 10 parts of zirconia sand were blended as base materials to produce Western tableware with a wall thickness of 5 mm and a radius of 6 inches, and fired at 1280° C. for 2 hours.

The specific gravity of the obtained product was 3.2, and the thermal conductivity was 0.0.
028Ca j! / ”C・am・sec,
Its chemical composition was as follows.

S! Oz: 25 wt%, 412203 =
62tstt%, ZrO2: 5 wt%, Ti
0z: 3 wt%, (NazO+KzO):
2.5 wt%, CaO: 0.5 wt%, F
e40z: 1wt%, while 50 parts of feldspar, 40 parts of clay
A glaze having the following chemical composition was prepared by mixing 1 part of lime, 3 parts of lime, 10 parts of zirconia, and 5 parts of glass frit.

. 5iOz: t, a mol, AβzOi: 0
．． 4 mol, (KZO+NaZO): 0.4 mol, B
, O,: 0.1 mol, CaO: 0.1 mol Based on this glaze, a 50 wt% aqueous glaze solution and a coating thickness of 1.4 μm were used. Each 70wt% aqueous glaze solution was prepared for Oam use, and the pottery was dipped into the glaze solution and coated on the entire surface, pre-dried, and then fired at 1000°C for 15 minutes.

The thermal conductivity of the generated glaze layer is 0.0012Ca! ! /
cm -°C·sec.

Next, it was placed in a 92° C. incubator and maintained at a constant temperature for 2 hours, and then taken out and left on a table at room temperature to observe how the temperature decreased.

The results are shown in Table 5, and it can be seen that even if the base materials have the same heat capacity, the heat storage properties differ significantly depending on the thickness of the glaze layer.

"Effects of the Invention" It is clear that the present invention as explained above has the desirable feel, solidity, and style of ceramic tableware, and also maintains a suitable temperature for eating and drinking for a long period of time. It is obvious that the above-mentioned heat storage type tableware can be obtained relatively easily and at low cost since such an effect is generally obtained by a single-layer product, and it is also strong. Because of its excellent properties, it is possible to provide ceramic tableware that can withstand cleaning and other handling not only as tableware for general household use but also for use in hotels, banquets, schools, hospitals, etc. that handle a large number of foods. Therefore, it is clear that it has an outstanding industrial effect.

[Brief explanation of drawings]

The drawings illustrate the technical contents of the present invention, and FIGS. 1 to 6 are partially cutaway side views showing some examples of ceramic tableware according to the present invention. In these drawings, 1 is the base material, 2 is the glaze-baked layer, and 3 is the conventional glaze-baked layer. Patent applicant Nippon Light Metal Co., Ltd. Inventor Mamoru Takahashi Procedural amendment (voluntary)

Claims (1)

[Claims] 30 to 70 wt% of either or both alumina and zirconia raw materials are blended into the ceramic material,
Thermal conductivity is 0.0 on the base surface of the vessel whose specific gravity is 2.6 or more.
022cal/cm・℃・sec or less, thickness 0.5m
A heat storage type ceramic tableware characterized in that at least the open surface side is coated with a baked glaze layer of m or more.