JPH01182275A - Reheatable sealed laminated container - Google Patents

Abstract

PURPOSE:To permit foods received in a container to be uniformly heated for cooking, independently of the water content thereof and the uneven distribution of the foods in the container, by providing a layer containing not less than two layers of far- infrared radiative ceramics of differing wavelengths and wavelength distributions on the inner surface of a base material composed of a layer containing a metal capable of generating heat by a microwave. CONSTITUTION:The wall of a container is of a laminated structure formed by a base material 6 composed of a layer containing a metal capable of generating heat by a microwave and layers 7 and 8, each containing not less than two layers of far- infrared radiative ceramic of differing wavelengths and wavelength distributions, provided on the inner surface of the base material. The aforesaid wall and a lid 5 are heat sealed together through a flange 3 to form a sealed laminated container. Since each of the ceramics-containing layers 7 and 8 is composed of not less than two layers of differing wavelengths and wavelength distributions, the radiative far- infrared rays are amplified while subjected to complex refractions passing through a boundary between each layer. Therefore, the far-infrared rays are radiated upon foods received in the container in many directions, thereby attaining a uniform heating thereof and hence a good cooking.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a sealed laminated container that can be heated and cooked in a microwave oven, toaster oven, etc.
More specifically, 2f! with different wavelengths or wavelength distributions are formed on the inner surface of the base material. The present invention relates to a sealed laminated container that is provided with a ceramic-containing layer that has far-infrared radiation of a level higher than that of the same class, thereby increasing the heating effect.

(Prior art and its problems) Far infrared rays emitted from ceramics have an excellent heating effect on substances, and are also effective in cooking and sterilizing food. Are known.

For example, JP-A No. 61-142163 discloses that the outer layer, the intermediate layer, and the inner layer are composed of a paper-like material,
A food container is described that is made of synthetic resin or metal and the intermediate layer is ceramic, and in this container, far infrared rays are emitted when a temperature change is applied to the ceramic.
It is also described that the penetrating effect of this far infrared rays prevents temperature changes in the food in the container.

However, this invention aims to prevent as much as possible the temperature change of the food contained in the container, that is, to improve the heat retention of the container, and is aimed at improving the radiation efficiency of far infrared rays from the ceramic layer. However, if a plastic layer is provided adjacent to the ceramic layer in such a container, there is a problem in that the radiation efficiency of far infrared rays will be greatly reduced due to the transparency of the plastic layer. be.

Furthermore, JP-A-60-188115 describes a technology related to an oil cooking device, which includes arranging a ceramic that emits far infrared rays when heated on the inner bottom of the pot;
Further, as an example of the shape of this ceramic, a disk-like shape having a large number of concave portions and convex portions formed on the upper surface and a through hole provided therein is exemplified. By arranging the shape of the ceramic as described above, far infrared rays are emitted in all directions within a 180° range from the concave and convex portions and the sloped surface between them, so that the far infrared rays are emitted from only one point on the food to be cooked. The effect of preventing localized overheating due to concentration of far-infrared radiation is explained.

However, the ceramic disclosed in this invention emits far infrared rays in many directions, so although it is significant in that it has excellent heating efficiency, it also emits far infrared rays in many directions. In order to form concave and convex surfaces on the top surface of the ceramic plate,
It is necessary for the ceramic plate to have a certain degree of thickness, and such a shape cannot be applied to thin-walled laminated containers such as those used for cooking food in a microwave oven.

(Objective of the Invention) Therefore, the object of the present invention is to uniformly radiate far-infrared rays from multiple directions to foods stored in containers by providing two or more ceramic-containing layers with different wavelengths or wavelength distributions. To provide a laminated container capable of uniformly heating and cooking food stored in the container regardless of water content or its uneven distribution.

(Means for Solving the Problems) According to the present invention, a base material made of a metal-containing layer capable of generating heat by microwaves, and a layer having a different wavelength or wavelength distribution on the inner surface side of the base material. A reheatable sealed laminated container is provided, which is characterized by being provided with a ceramic-containing layer having far-infrared radiation properties greater than that of the ceramic layer.

(effect) FIG. 1, which shows an example of the container of the present invention, will be explained.

This container is composed of a cylindrical or tapered side wall 1, a bottom wall 2 that extends to the lower end of the side wall, and a flange 3 that extends to the upper end of the side wall.
is formed.

The container wall of each part has a base material 6 consisting of a metal-containing layer capable of generating heat using microwaves, and two or more layers with far-infrared radiation having different wavelengths or wavelength distributions provided on the inner surface thereof. It has a laminated structure consisting of ceramic-containing layers 7 and 8, and a sealed laminated container is formed by heat-sealing the lid 5 through the flange portion 3.

In the present invention, paper, thermoplastic resin, or a laminate thereof may be further provided as an outer layer on the outer surface side of the metal-containing layer.

That is, the container of the present invention is characterized in that two or more ceramic-containing layers having far-infrared radiating properties with different wavelengths or wavelength distributions are provided on the inner surface of the base material consisting of a metal-containing layer. .

When a container having such a layered structure is filled with food and heated in a microwave oven, toaster oven 1, or other heating mechanism, the metal-containing layer 6 is heated, and the heat causes the ceramic-containing layer 7.8 heats up and emits far-infrared rays. At this time, since the ceramic-containing layer 7.8 is composed of two or more layers each having a different wavelength or wavelength distribution, the radiated far infrared rays are refracted in a complicated manner at the interface of each layer. As a result, the far-infrared rays are radiated from multiple directions to the food stored in the container, greatly increasing the heating efficiency of the food, allowing the far-infrared rays to penetrate deep into the food contents. Since the radiation directions are multi-directional, more uniform heating can be achieved and good cooking can be achieved.

Furthermore, a metal-containing layer 6 is provided on the outside of the ceramic-containing layer 7.8.
Due to the presence of the metal-containing layer, the far-infrared rays emitted outward from the ceramic-containing layer are all reflected inward by the metal-containing layer, making it possible to heat the food contents even more efficiently. .

In the ceramic-containing layer, by making the outer layer (the ceramic-containing layer provided in contact with the base material) a layer with a smaller wavelength, efficient heat conduction is performed.

FIG. 2 showing another example of the container of the present invention will be explained. This container has at least two layers of ceramic containing layers with different wavelengths or wavelength distributions, each of which is not a single layer made of the same ceramic, but has two or more layers of ceramic, such as a striped pattern. It shows an aspect in which it is provided in a pattern.

According to this example, the ceramic-containing layer 8 is not of the same ceramic, but of several types of ceramic, and is provided as a patterned layer 9, 10 in the form of diagonal stripes, the outer ceramic-containing layer being opposite to the inner layer. Diagonal striped pattern 11.1
2.

As in this example, even if the ceramic-containing layers are patterned and provided in multiple layers, if each ceramic has a different wavelength or wavelength distribution, uniform and efficient It is capable of far-infrared heating.

(Description of preferred embodiments) The ceramic having far-infrared radiation used in the present invention has a microwave heating temperature of generally 80 to 160
At a temperature of ℃, the spectral emissivity (sample radiation intensity per black body radiation intensity) in the far infrared region, especially from 3 to 14 μm, is 80%.
Among the above, in particular, 2f with wavelengths different by 1 μm or more, preferably 2 μm or more from among those that are 90% or more! This type of ceramic is used by laminating at least two layers.

Ceramics having such far-infrared radiation include alumina (A-poor zos), zirconia (ZrO2),
Mullite (3A/!, os・2SiOs), cordierite (2Mg0・2A6203・5Si02), titania (Ti02), steatite (MgO-5i(h)
, silica (Si(h), oxide ceramics such as silica alumina; silicon carbide (SIO), tungsten carbide (WC),
Carbide ceramics such as zirconium carbide (ZrC); nitride ceramics such as boron nitride (BN), titanium nitride (TiN), and silicon nitride (SiaN4); borides such as zirconium boride (ZrB2) and titanium boride (TiB2) Ceramic; Examples include silicide ceramics such as tungsten silicide (WSi2) and molybdenum silicide (MoSi2),
Among these, preferable ceramics that have little effect on foods, etc. include one type or a mixture of two or more of titania, alumina, silica, cordierite, etc., but in particular titania-cordierite, alumina - The combination of cordierite is excellent because the difference in wavelength is moderate.

Figures 3, 4, and 5 of the attached drawings show the temperature at 140°C.
The far-infrared spectral intensity curves of alumina, titania, and cordierite are shown in (dotted lines indicate specifics). From this drawing, titania is a radiant material with excellent emissivity, and alumina has good emissivity and is inexpensive, so
It is desirable to use at least one of these as the ceramic in the present invention.

The metal-containing layer in the present invention means a metal-containing layer that transmits microwaves, such as a metal foil, a metal vapor-deposited film, an electroless plating film, or a packed layer of metal fibers or metal powder.

Metals tend to reflect microwaves when they are thick, so microwaves rarely generate heat.
In a thin state, the metal-containing layer tends to transmit microwaves, and generates heat due to the eddy current generated when the microwaves transmit, so the metal-containing layer of the above type becomes a heating element by microwaves.

Thus, the heat generated by the heating and conducted from the metal-containing layer 6 is amplified by the ceramic-containing layer 7 and further conducted to the other ceramic-containing layer 8 .

At this time, the far infrared rays emitted at the interface between the ceramic layers go through complicated refraction because both layers have different wavelengths or wavelength distributions, and the amount of heat is further amplified. It will heat up.

The ceramic inner layer and outer layer may be provided on the inner and outer surfaces of a pre-formed container, or they may be coated on the inner and outer surfaces of a base material and then formed into a container shape such as a tray or cup using a sheet forming method such as vacuum forming. Good too.

In the present invention, the amount of ceramic coating per layer is generally 0.05 to 5 g/dI112, preferably 0.1 to 2 g/dm2, although it varies depending on the type of ceramic.

In order to provide two coating layers of far-infrared radiating material on the inner surface of the container base material, a thin film forming method such as evaporation, ion beam evaporation, plasma evaporation, thermal spraying, chemical vapor deposition, or sputtering is used to form each ceramic layer. Methods such as directly applying the paint to the inner surface of the container material, applying a ceramic-containing paint to the inner surface of the material, or laminating two ceramic-containing resin layers on the inner surface of the material are adopted.

The ceramic used as the ceramic-containing resin coating generally has a particle size of 0.1 to 100 μm, particularly 0.3 μm.
It is preferable to use particles of 50 μm to 50 μm. Examples of coating film forming resins include epoxy-phenol paints, epoxy-amino paints, epoxy-acrylic paints, epoxy-vinyl paints, thermosetting acrylic paints, vinyl paints, vinyl-amino paints, etc. used.

(Effects of the Invention) According to the present invention, the food contents can be stored stably for a long period of time by sealing, and when the food contents are required, they can be stored in a microwave oven, a toaster oven 5, or other heating means. The food contents can be cooked by heating the food contents in each container, and in this case, the container itself has excellent heat resistance during heating, and the food contents can be heated uniformly and efficiently from multiple directions. It is possible to provide packaging containers that can

(Example) Example 1 On the inner surface of aluminum foil with a thickness of 50 μm, an average particle size of 25 μm was added.
Cordierite (2Mg0・2Af 203・5
A 75 μm polypropylene film containing 50% by weight of SiO2) and a 70 μm polypropylene film containing 50% by weight of titania (TiO2) with an average particle size of 20 μm are sequentially laminated on the polypropylene film side to form a three-layer structure. I got a laminate.

This laminate was press-molded to form a tray-shaped container with a length of 180 mm, a width of 110 mm, and a depth of 20+ nm. This container containing about 95% of the internal volume of gratin was heated in the center of an 800W microwave oven for 8 minutes. When we measured the temperature at 10 evenly spaced locations throughout the gratin, the final temperature at each location was within the range of 74 ± 1°C, indicating that heating was extremely uniform and efficient. It has been proven that there is.

Example 2 An average grain size of 25 μm was applied to the inner surface of a 50 μm thick steel foil.
m cordierite (2Mgo・2Af 20s・5
An epoxy-amino paint containing 50% by weight of Si02) was applied to form a coating film with a thickness of about 65 μm. After this coating film had dried, a layer with an average particle size of 2
An epoxy-amino paint containing 50% by weight of 0 μm alumina (AfzOs) was applied to form a coating film with a thickness of about 60 μm.

This laminate was press-molded to a length of 180 mm,
A tray-shaped container with a width of 110 mm and a depth of 20 mm was molded. This container was filled with about 95% of its internal volume of stew and heated in the center of an 800W microwave oven for 8 minutes. When we measured the temperature at 10 equally spaced locations throughout the stew, the final temperature at each location was 73±1°C.
It was proved that heating was performed extremely uniformly and efficiently.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the container of the present invention, FIG. 2 is a sectional view showing another example of the container of the invention, and FIGS. FIG. 2 is a diagram showing far-infrared spectral intensity curves of alumina, titania, and kobueyerite in C. In Figures 1 and 2, 1... Side wall part, 2... Bottom wall part, 3...
...Flange part, 4... Food storage part, 5.
...Lid body, 6...Base material, 7...
Ceramic-containing outer layer, 8... Ceramic-containing inner layer, 9.10... Patterned ceramic-containing inner layer, 11.12... Ceramic-containing outer layer formed into a nopetan. Patent applicant: Toyo Seikan Co., Ltd.

Claims (1)

[Claims] (1) A base material consisting of a metal-containing layer that can generate heat using microwaves, and two or more ceramic-containing layers having far-infrared radiating properties with different wavelengths or wavelength distributions on the inner surface of the base material. A reheatable sealed laminated container characterized by: