JPH0667341B2 - Microwave oven sealed container - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hermetically-sealed container for containing food, and more particularly to releasing steam generated when cooking in a microwave oven while food is contained in the hermetically-sealed container. TECHNICAL FIELD The present invention relates to a sealed microwave cooking container in which a hole is automatically opened in a lid of the container.

[Conventional technology]

When cooking food in a sealed container made of plastic, paper, or the like in a microwave oven, it is convenient to be able to heat the food in a sealed container. When the food in the sealed container is heated in the microwave oven, the pressure in the container increases due to the generation of steam, and the container bursts. At this time, the food in the container may be scattered outside. Further, when the food is heated except for the lid of the hermetically sealed container, the water vapor from the food is large and the food is deteriorated. Therefore, in order to solve the above problem, a means for automatically opening the lid of the container when heating the food in the sealed container in a microwave oven has been proposed. Japanese Patent Laid-Open No. 61-6957
According to the technique proposed in No. 6, the container lid is provided with an adhesion layer of non-metallic microwave absorbing particles. Also, in accordance with the technique disclosed in U.S. Pat. No. 4,210,674, a conductive material is provided on the lid of the container and the vapor conductive material is sized and shaped to be suitable for microwave absorption. A means for heating and melting the lid and opening the lid by the microwave absorbing substance provided on the lid in this manner has been proposed.

[Problems to be solved by the invention]

In a microwave oven and a microwave cooking cabinet, a standing wave is generated in the cabinet and the microwave intensity in the cabinet is not uniform and has a distribution. According to the above-described conventional method of absorbing only microwaves and generating heat, when the heat generating substance is placed in the region where the microwave intensity is weak, the amount of heat generation is insufficient and the lid may not be opened. Further, since the heat-generating substance is made large in size because it is opened even in the region where the microwave is weak, if it is placed in the region where the microwave intensity is strong, a large hole is opened, the water vapor from the food is large, and the food deteriorates.

The present invention has been made to solve the above-mentioned problems of the prior art. The lid of the insulative flexible sheet of the hermetically sealed container is rapidly heated in a short time by microwave heating and melted and opened to an appropriate size surely. An object is to provide a sealed container for microwave oven cooking.

The insulating flexible sheet as referred to herein means a thermoplastic plastic sheet, a thermosetting plastic sheet, a paper material or the like alone or a sheet composed of two or more thereof.
As the thermoplastic, linear polyester such as polyethylene terephthalate, polyethylene, polypropylene, ethylene-propylene copolymer, polyolefin resin such as ionomer, acrylic resin, polystyrene resin, AS resin, ABS resin, polyamide resin,
Polyimide resin, polyimine resin, polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride-vinyl acetate copolymer, vinylidene-based copolymer, acetal resin, diallyl phthalate resin, fluorine-based resin, and resins composed of a plurality of combinations thereof. Etc.

Examples of thermosetting plastics include urea resins, phenol resins, epoxy resins, melamine resins, urethane resins, xylene-formaldehyde resins, and resins composed of a combination of a plurality of these.

[Means for solving problems]

An antenna made of a conductor is laminated on the lid body of the container which is sealed by the lid body made of an insulating flexible sheet,
When the container is exposed to microwaves in a microwave oven, microwave energy is collected in the vicinity of the opposing tips of the antenna, the energy is converted into heat, and the heat opens the lid body.

If a heating element is arranged at the portion where the microwave energy is collected, the heat generating action is further enhanced. When the heating element is arranged, even if the antenna is not arranged oppositely, by disposing the heating element at the corner of the antenna, microwave energy is converted into heat by the heating element and the lid body can be opened by the heat. .

The heating element referred to here may be not only a high resistance element but also a material that absorbs microwaves to generate heat, that is, a material that generates heat not only by resistance loss but also by magnetic loss, dielectric loss or discharge.

MOFe ₂ O is a substance that generates heat due to magnetic loss.
Examples thereof include ferrite represented by ₃ (M: divalent metal ion), iron, cobalt, nickel, and a ferromagnetic alloy composed of a combination of a plurality of these. Examples of the heating element due to dielectric loss include polymer compounds such as epoxy resin, neoprene, bakelite, nylon, and substances with large relative dielectric loss such as barium titanate.
Further, examples of the heating element by the discharge include a vacuum deposition film made of a metal material such as aluminum, iron and nickel, a vacuum deposition film made of a semiconductor material such as silicon, and a fibrous substance made of these materials.

[Operation] An alternating current flows in the microwave, which is a good conductor, in the microwave, and a high-frequency high electric field and high magnetic field are generated at the positions where the antennas face each other and at the corners of the antenna. If a resistor, which is a heating element, is arranged at the position where the high electric field and the high magnetic field are generated, heat is generated by Joule heat of the current flowing through the heating element, and the dielectric, which is the heating element, is arranged at the position of the high electric field. Then, heat is generated by dielectric heating of the dielectric. Furthermore, if a magnetic material, which is a heating element, is placed at a position where a high magnetic field is generated, heat is generated due to a hysteresis phenomenon under the magnetic field. Since the antenna does not substantially generate heat, even if the size is increased, the heat dissipation is small and the large amount of energy collected by the large size antenna is converted into heat by the small heating element, so the lid body is rapidly heated to a high temperature. It can be heated.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing a first embodiment of the present invention.
In the figure, reference numeral 1 denotes a lid body made of a thermoplastic plastic sheet, which is heat-sealed to a flange portion of a plastic container 2 containing a preserved food. A C-shaped antenna 4 made of a conductive material and a heating element 5 made of a high resistance material are laminated on the lid body 1. The position of the heating element 5 is above the heat-sealing portion of the lid body, and the position of the antenna 4 is the position sandwiching the heating element 5. The antenna is formed by coating conductive paint containing conductive powder, vacuum deposition method, sputtering method, spraying method of conductive material, chemical plating method or adhesion of metal foil, and the heating element is made of binder containing high resistance particles. It can be formed by painting or adhering a conductive plastic sheet. These may be laminated directly on the lid body, or may be laminated on a plastic sheet to form a label and the label may be adhered to the lid body.
When the heating element is formed by coating a binder containing high-resistance particles, the binder melts when the heating element is heated to a certain temperature or more, and the heating action stops, so the lid body is abnormally heated and thermal decomposition occurs. Things can be prevented. A foamable substance 6 is attached to a position of the flange portion of the container 2 facing the heating element 5. When the package configured in this manner is exposed to microwaves in a microwave oven, the current flowing through the antenna 4 generates a high electric field in the heating element 5 and the current flows inside the heating element 5 to generate heat. The seal portion heated by the heating element 5 melts and opens. The container and the lid main body can be easily separated by pulling the opened seal portion after microwave oven cooking. If a foaming substance is attached to the opening seal portion as in this embodiment, the lid can be separated more easily.

FIG. 3 is a plan view of a lid used for the hermetically sealed container according to the second embodiment of the present invention. In the figure, reference numeral 4 denotes an antenna made of a conductor, which is laminated on the lid main body 1 as in the first embodiment. The lid body 1 is heat-sealed in a container as in the first embodiment. In the case of the present embodiment, a high electric field is generated between the opposing tips of the C-shaped antenna 4 through which a current flows by the microwave, and the antenna tip proximity portion 1'of the lid body is dielectrically heated and melted and opened.

FIG. 4 is a plan view of a lid used for the hermetically sealed container according to the third embodiment of the present invention. In the figure, 4 and 4 are antennas made of a conductor, which are laminated on the lid body 1 as in the first embodiment. The heating element 5 is connected to both the antennas 4 and 4 and the heating element 5 is laminated on the lid body. This heating element may be made of the same material as the antenna or a different material, but the resistance value per unit length is the antenna. It needs to be large compared to. If the antenna and the heating element are made of the same material, the heating element must be smaller in width or thickness than the antenna. In the present embodiment, the heating element is connected to the antenna, but it may be in a proximity state without being connected. If such a lid is used as in the first embodiment, a high electric field is generated between the antennas 4 and 4, and a current flows through the heating element 5 to generate heat.

FIG. 5 is a plan view of a lid used for the hermetically sealed container according to the fourth embodiment of the present invention. In the figure, reference numeral 4 denotes an antenna made of a conductor, which is laminated on the lid main body 1 as in the first embodiment. A heating element, which is connected to a corner of the antenna 4 and has a resistance higher than that of the antenna, is laminated on the lid 5. In the present embodiment, the heating element is connected to the antenna, but it may be in a proximity state without being connected. If such a lid is used as in the first embodiment, a high electric field generated by the antenna 4 is applied to the heating element 5 and the heating element 5 generates heat to melt and open the lid body 4.

FIG. 6 is a plan view of a lid used for the sealed container which is the embodiment of FIG. 5 of the present invention. In the figure, reference numerals 4 and 4 denote antennas made of a conductor, and are arranged in a state in which the tips are close to each other.
The lid body 1 is laminated in the same manner as in the above embodiment. When such a lid is used as in the first embodiment, the high electric field generated between the antennas 4 and 4 causes the portion 1'of the lid body near the antennas 4 and 4 to be dielectrically heated and melted and opened.

FIG. 7 is a plan view of a lid used for the hermetically sealed container according to the sixth embodiment of the present invention. In the figure, 4 and 4 are antennas made of a conductor, and in the state where the ferrite BSF-547 manufactured by Toda Kogyo and the heating element 5 made of epoxy resin are close to each other between the long sides of the antenna, as in the first embodiment. Lid body 1
To be laminated. If such a lid is used in the same manner as in the first embodiment, the ferrite generates heat and opens linearly.

FIG. 8 is a plan view of a lid used for the hermetically sealed container according to the seventh embodiment of the present invention. In the figure, 4 and 4 are antennas made of a conductor, which are laminated on the lid body 1 in the same manner as in the first embodiment, with the heating elements 5 made of a metal aluminum vapor deposition film being close to each other between the tip portions. If such a lid is used in the same manner as in the first embodiment, the vapor deposition film generates heat due to the high electric field generated between the antennas 4 and 4, and the lid is opened.

FIG. 9 is a plan view of a lid used for the hermetically sealed container according to the eighth embodiment of the present invention. In the figure, 4 is a C-shaped antenna made of a conductor, and 5 is a heating element made of barium titanate and epoxy resin, which is laminated on the lid main body 1 in the state of being close to the antenna as in the first embodiment. . If such a lid is used as in the first embodiment, the barium titanate-epoxy resin is dielectrically heated by the high electric field generated between the antennas 4, and the lid is opened.

〔The invention's effect〕

As described above, microwave energy is collected by an antenna with a large size, and this is converted into heat in a narrow part, so that the lid of the container can be rapidly heated to high temperature, and the sealed container of the microwave can be reliably heated during microwave oven cooking. The lid can be opened. Further, when the opening is provided in the seal portion, the lid and the container can be easily separated.

[Brief description of drawings]

1 is a plan view of a hermetically sealed container according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a hermetically sealed container according to a second embodiment of the present invention. FIG. 4 is a plan view of a lid used for a sealed container according to a third embodiment of the present invention, and FIG. 5 is a plan view of a lid used for a sealed container according to a fourth embodiment of the present invention. FIG. 6 is a plan view of a lid that is used, and FIG. 6 is a plan view of a lid that is used in a sealed container that is a fifth embodiment of the present invention. FIG. 7 is a plan view of a lid used for a hermetically sealed container according to a sixth embodiment of the present invention, and FIG. 8 is a plan view of a lid used for a hermetically sealed container according to the seventh embodiment of the present invention. The figure is a plan view of a lid used for a hermetically sealed container according to an eighth embodiment of the present invention. 1 ... Lid body, 2 ... Container, 3 ... Preserved food, 4 ... Antenna, 5 ... Heating element, 6 ... Foaming substance

Claims (8)

[Claims] 1. A container sealed by a lid body made of an insulating flexible sheet, wherein an antenna made of a C-shaped conductor is laminated on the lid body, and the container is a microwave oven. A microwave-sealed sealed container for microwave cooking, wherein microwave energy is collected by the antenna in the vicinity of the opposite end of the antenna when exposed to waves, the energy is converted into heat, and the lid body is opened by the heat. 2. A heating element that is heated by microwaves is stacked between the opposite end portions of the antenna close to or connected to the antenna, and the microwave energy collected by the antenna is converted into heat by the heating element. The sealed container for microwave oven cooking according to claim 1. 3. The sealed container for microwave oven cooking according to claim 1, wherein a position where the lid body is melted and opened is a sealing portion with the container. 4. A container hermetically sealed by a lid body made of an insulating flexible sheet, wherein a plurality of antennas made of a conductor are laminated on the lid body, and the container is microwaved in a microwave oven. A microwave-sealed container for microwave cooking in which microwave energy is collected by the antenna in the vicinity of the opposite end portion of the antenna when exposed, the energy is converted into heat, and the lid body is opened by the heat. 5. A heating element that is heated by microwaves is laminated between adjacent tip portions of the antenna so as to be close to or connected to the antenna, and the microwave energy collected by the antenna is converted into heat by the heating element. The sealed container for microwave oven cooking according to claim 4. 6. The container for microwave oven cooking according to claim 4, wherein a position where the lid main body melts and opens is a sealing portion with the container. 7. A container sealed by a lid main body made of an insulating flexible seal, wherein an antenna made of a conductor is laminated on the lid main body, and a heating element is provided at a corner portion provided on the antenna. When in close proximity or connected and the container is exposed to microwaves in a microwave oven, the antenna collects microwave energy, which is converted into heat by the heating element, which heat opens the lid body. A sealed container for microwave oven cooking. 8. The sealed container for microwave oven cooking according to claim 7, wherein a position where the lid body is melted and opened is a sealing portion with the container.