JPH02211112A - Microwave absorption and heat generation type cooking container - Google Patents

Abstract

PURPOSE:To enable the efficient baking of a food, for example, frozen pizza of small to large size with a scorched line by providing a microwave absorption and heat generation metal oxide film on the surface of the cooking container base material of density quality and lithia ceramic. CONSTITUTION:A microwave absorption and heat generation metal oxide film 3 (e.g. tin oxide) is formed on the surface of a cooking container base material 2 made of density quality and lithia ceramic, thereby making a microwave absorption and heat generation cooking container 1. This container 1 is placed in a microwave oven and, for example, a microwave of 500W output is irradiated, thereby enabling heat generation up to 400 to 500 deg.C in three minutes. By using the aforesaid container 1, it is possible to efficiently bake a food such as pizza of small to large size with scorching.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a microwave-absorbing exothermic cooking container, which is particularly used for browning and baking cooking ingredients in a microwave oven.

(B) Conventional technology Conventionally, microwave ovens guide microwaves emitted from a magnetron into the oven chamber and irradiate the cooking ingredients to heat the ingredients for cooking, so they are suitable for browning and baking. There wasn't.

Therefore, we installed a sheathed heater inside the oven.
A microwave oven has been developed that uses heat radiated from the sheathed heater in addition to microwaves to heat cooking ingredients, but two types of heating means, a magnetron and a sheathed heater, must be provided as heat sources. Therefore, there are problems in that it increases the cost, complicates the configuration, and increases the size of the entire device.

In recent years, heating elements made of double-layered plates made by bonding a heat-generating substance (e.g. silicon carbide or ferrite) and an inorganic heat-insulating base material (e.g. glass or ceramic) that generate heat when irradiated with microwaves, or silicon carbide, have been developed. A microwave-absorbing, exothermic, electrically conductive gold dioxide thin film is formed on the heating element of the system ceramic molded plate, and on the surface of microwave-transparent glass, ceramics, and ceramics, allowing dielectric heating and thermal radiation using only microwave irradiation. Heating elements have been developed that are capable of both heating and heating.

(c) Problem to be solved by the invention The outer surface of a metal bread-making container that does not transmit microwaves (
150-160 A single-function microwave oven for home bakeries that heats bread to ℃ and browns it has been commercialized. recent years,
Furthermore, as microwave cooking methods for browning frozen foods have become popular, the temperature generated by microwaves has become higher. 400-500℃ in a short time
There is a demand for a microwave-absorbing exothermic cooking container that generates heat, but the conventional microwave-absorbing exothermic cooking container is
For example, the diameter is 200 to 300 mm.

Even when a concave container with a thickness of 1 to 01 was irradiated with microwaves with an output of 500 W for 3 minutes, the exothermic temperature was only 300°C.

This invention was made to solve the above-mentioned conventional problems, and aims to provide a microwave-absorbing exothermic cooking container that generates heat to 400 to 500° C. in a short period of about 3 minutes.

(d) Means for Solving the Problem This inventor has developed a method for heating 450 to 500°C in a short period of about 3 minutes.
In order to provide a microwave-absorbing, exothermic cooking container that generates heat, we conducted intensive research on ceramic cooking container base materials, and found that the microwave-absorbing, exothermic metal oxide film formed on the surface of the dense lithium ceramic was This invention was achieved by discovering the fact that 7() has a significantly high level of energy conductivity.

According to the present invention, there is provided a microwave-absorbing heat-generating cooking container having a microwave-absorbing heat-generating metal oxide film on the cooking container base material surface made of dense lithium ceramic.

O4 The dense lithium ceramic cooking container base material is
For example, lydium minerals such as lysiakite, petalite, eucryptite, beniunmo, chinwaldeunmo, manandonite, triphyllite, lysiophyllite, ambrigoite, fremontite, and silafurite, among which lydiumite and petalite are preferred. A powder having an average particle diameter of usually 1.0 to 3.0 μm obtained by pulverizing the powder is mixed with a binder such as polyvinyl alcohol or methyl cellulose and water and kneaded and pressed to form a kneaded mixture. This kneaded surface is molded into a predetermined shape using a molding machine such as an extrusion molding machine or a compression molding machine, and then dried at a temperature of usually 500°C or less while being placed in a frame to prevent the shape from deforming. It is removed by evaporation or combustion, and then fired at a temperature of usually 500 to 1,300°C to produce a dense molded body containing β-subodium structure as a main component. During the kneading process, 90 to 110 fTfm of powder of the 11 minerals listed in nQ and 2 parts of the binder are added.
It can be prepared by mixing 0 to 30 parts by weight, 20 to 30 parts by weight of water, and 3 to 7 parts by weight of other minerals such as Honbushi clay and kaolin.

+iir firing is usually from 500 to 600°C to 1220°C.
It is preferable to gradually raise the temperature to ~1300°C, usually for 45 to 55 hours, and suitably maintain the temperature at least 1220°C to 1300°C, usually for 3 to 5 hours.

The microwave-absorbing exothermic metal oxide film in this invention is for heating cooking ingredients contained in a cooking container, and typically has a sheet resistivity of 102 to 103 Ω/cm'', and has a microwave-absorbing exothermic metal oxide film. It is suitable to have a film thickness of usually 0.1 to !μm, which can absorb heat and generate heat. It can be formed on the base material surface of a lithium-based ceramic treatment container by a vapor deposition method or a sol coating method.
The single-wave absorbing exothermic metal oxide film may be formed directly on the lithium-based ceramic cooking container base material surface, but it is better to form it with a heat-resistant black pigment layer interposed therebetween to prevent microwave irradiation. The infrared rays emitted from the microwave-absorbing exothermic cooking container are 1 to 4 μm in diameter, which has a high contribution rate to heating efficiency.
It is preferable because it contains more infrared rays with a wavelength of , so cooking ingredients can be baked efficiently and with a moderate color tone.

The heat-resistant black pigment layer is formed of a heat-resistant black pigment powder made of a transition metal oxide, an inorganic binder, etc., on either the inner surface, the outer surface, or both the inner and outer surfaces of the lithium ceramic cooking container base material. The coating liquid is applied by, for example, a printing method, a spraying method, a dipping method, etc., and after drying, it is usually
It can be fired at ~1250°C to form a film with a normal thickness of 20-100 μm. The coating liquid contains 25 to 35 parts by weight of a heat-resistant black pigment based on an oxide of a transition metal such as copper, chromium, manganese, or cobalt, such as AQtOs Bt.
US 5ift system (softening point 900℃), LitO+
90 to 110 parts by weight of an inorganic binder with a low coefficient of thermal expansion such as hatos 5iot type (softening point 1100 ° C.),
For example, it can be prepared by adding 5 to 15 parts by weight of a binder such as ethyl cellulose or terpineol, a low viscosity modifier, a surfactant, etc., and 1 part of 50 to 80 parts by weight of atomized water.

(E) Effect: The dense lithium-based ceramic structure easily forms a tin oxide layer with high electrical conductivity on the surface, and as the temperature rises, the electrical resistance decreases, forming a microwave-absorbing exothermic metal oxide film. It facilitates the flow of microwave absorption surface current, limits the microwave absorption exothermic temperature due to its thermal insulating properties, and emits a large amount of far infrared rays to promote browning of the food to be cooked.

(f) Example Embodiments of the invention will be described with reference to the drawings.

Example! Li, 04% or more, ^12, 0.20%, Si Ot
Petalite (Li, O,
^12ffiO1・8SiOz) powder and Honbushi clay 1
100 parts by weight of this mixed powder, 22 parts by weight of methylcellulose as a binder and 24 parts by weight of water were mixed in a ratio of 00:5, and kneaded using a roll kneader. , perform kneading to prepare a kneaded surface.

Next, the kneaded surface was molded into a 11-shaped shape using a compression molding machine, and this molded product was placed in a frame so as not to lose its shape and placed in an electric furnace, and the temperature was increased from room temperature to 500 °C at a heating rate of 2 °C/min. The temperature was raised to 1260°C, the binder was removed by incineration, and the binder was removed by incineration by holding at 500°C for 1 hour.
The temperature was gradually raised to 1260°C over 44 hours, and then fired at 1260°C for 4 hours to produce a dense lithium-based ceramic with a diameter of 200Iffi, whose main component was a β-subodumene structure.
A cooking container base material with a thickness of 3 mm was produced.

Next, aqueous ammonia is added to the aqueous solution of stannic chloride until phenolphthalein becomes colored to form a gel, and this gel is adjusted to 5nOtlO% by adding ammonia and water to the water-washing tank, and the autoclave is heated. using 22
Hydrothermal treatment was performed at 0° C. for 4 hours to prepare a SnO* gel coating solution, and this coating solution was applied to the center of the back surface of the lithium ceramic cooking container base material 2 with a diameter of 120 mm as shown in FIG.
III11, dried at 100°C for 1 hour, and baked at 500°C for 30 minutes to form a microwave-absorbing exothermic tin oxide film 3 with a film thickness of 1μ and a sheet resistivity of 10” to 1G3Ω/cm”. A microwave absorbing exothermic cooking container 1 was prepared.

Next, as shown in FIG. 2, the microwave-absorbing heat-generating cooking container 1 is placed on a dish-shaped body 4 using a ceramic sealing adhesive 5, and a microphone [1-wave absorbing heat-generating cooking utensil 6] is attached. This microwave absorbing exothermic cooking utensil 6 is connected to a magnetron 7, a waveguide 8, and a microwave irradiation port 9 as shown in FIG.
, is installed in a microwave oven 11 consisting of a heating chamber 10, and has an output of 5.
When irradiated with 00W microwave, the microwave absorbing exothermic cooking container 1 reached 450°C in 3 minutes of irradiation time as shown in Fig. 4, which was higher than the conventional microwave absorbing exothermic cooking container 1. A significant improvement in heat generation properties was confirmed.

Example 2 On the day of the example, 20 parts by weight of a copper oxide heat-resistant black pigment, AQtOs 11tOs-8i (
A coating solution consisting of 80 parts by weight of glass frit with a softening point of 900°C, 5 parts by weight of ethyl cellulose, 2 ffl parts of polyvinyl butyral, 1 part by weight of a surfactant, 5 parts by weight of dibutyl phthalate, and 3 parts by weight of terpineol was applied by a printing method. , a heat-resistant black film with a film thickness of 45 gm was formed by firing at 1190°C, and a microwave-absorbing exothermic tin oxide film was formed on this heat-resistant black film.
A microwave-absorbing exothermic cooking container made of lithian ceramic was produced in the same manner as described above. It was confirmed that this microwave-absorbing heat-generating cooking container made of lithian ceramic exhibited good heat-generating properties as in Example 1, and it was possible to efficiently brown a large frozen pizza and bake it to a suitable color tone. confirmed.

Comparative Example 1 In Example 1, instead of raising the temperature of the kneaded compact to 1260°C, the temperature was raised to 1150°C, and the temperature was held at 1150°C for 4 hours for firing. A microwave-absorbing exothermic cooking container was prepared in the same manner as described above. This microwave absorbing exothermic cooking container is made of porous lithium ceramics, the microwave absorbing exothermic tin oxide film has an area resistivity of 107 to 10"Q/c+++1, and is irradiated with microwaves with an output of 500 W. However, as shown in FIG. 4, the heat generation property was poor.

Comparative Example 2 In Example 1, instead of using the lithium ceramic cooking container base material, Sin, 1to3,
A composition for crystallized glass prepared by adding a crystal nucleating agent such as zirconia and some additives to LltOl is melted at a high temperature of about 1700°C, press-formed in the same manner as ordinary glass, and then slowly cooled to remove strain. This amorphous glass is heated to 90°C using a tunnel kiln for crystallization.
A microwave absorbing exothermic cooking container was produced in the same manner as in Example 1 except for using crystallized glass obtained by heating and firing at 0 to 1200°C. This microwave-absorbing exothermic cooking container had low exothermic properties as shown in FIG.

(G) Effects of the Invention According to the present invention, it is possible to provide a microwave-absorbing exothermic cooking container that generates heat to 400 to 500° C. in 3 minutes. By using the microwave-absorbing exothermic cooking container of the present invention, it is possible to efficiently brown and bake, for example, frozen pizzas ranging in size from small to large.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a microwave-absorbing heat-generating cooking container produced in an example of the present invention, and FIG. 2 is a cooking utensil constituted by a microwave-absorbing heat-generating cooking container produced in an example of the present invention. FIG. 3 is an explanatory diagram of the cooking utensil shown in FIG. 2 used in the embodiment of this invention arranged in a microwave oven.
FIG. 4 is a graph showing the exothermic properties of the microwave-absorbing exothermic cooking containers of Examples and Comparative Examples of the present invention. 1...Microwave absorbing exothermic cooking container, 2...
...Lithia ceramic cooking container base material, 3...
...Microwave absorbing exothermic tin oxide film, 4...
・Dish-shaped body, 5... Seal adhesive, 6.
...Microwave absorbing exothermic cooking utensil, 7...
・Magnetron, ... waveguide, 9...
Microwave irradiation port, 10... Heating chamber, 11...
····microwave oven. Figure 1 1!2W1 13 Figure

Claims (1)

[Claims] 1. On the surface of the dense lithium ceramic cooking container base material,
A microwave-absorbing exothermic cooking container comprising a microwave-absorbing exothermic metal oxide film. 2. The microwave-absorbing heat-generating cooking container according to claim 1, wherein a heat-resistant black coating is interposed between the dense lithium ceramic cooking container base material surface and the microwave-absorbing heat-generating metal oxide film.