JPH0811591B2 - Microwave oven sealed container - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hermetically-sealed container for containing food, and particularly for releasing steam generated when cooking in a microwave oven while food is contained in the hermetically-sealed container. The present invention relates to a sealed microwave cooking container in which a hole is automatically opened in the 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. According to the technique proposed in Japanese Unexamined Patent Publication No. 61-69576, a lid of a container is provided with an adhesion layer made of non-metallic microwave absorbing particles. Also, according to the technique disclosed in U.S. Pat. No. 4,210,674, a conductive material is provided on the lid of the container, and the size and shape of the conductive material are adjusted 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. By the way, 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.

In order to solve this problem, a relatively long conductive antenna is provided on the lid of the insulating flexible sheet of the hermetically sealed container to concentrate microwave energy when the antenna is exposed to microwaves in the microwave oven. Japanese Patent Application No. 62-250026 filed by the present applicant discloses a technique for rapidly heating a lid of a hermetically sealed container in a short time by energy to surely melt and open it to an appropriate size.

[Problems to be Solved by the Invention]

The technique disclosed in Japanese Patent Application No. 62-250026 has a considerable effect in reliably melting and opening the lid of the hermetically sealed container to an appropriate size. However, it has been found that the lid may not melt open depending on the type of microwave oven, the type and shape of the sealed container and contents or the location where the sealed container is placed in the microwave oven. The cause is considered as follows. That is, a standing wave is generated in the microwave oven, and the microwave intensity in the oven is not uniform and has a distribution. The microwave vibration direction is perpendicular to the traveling direction, but depending on the shape of the cabinet, the microwave radiation method and the opening position of the waveguide, and the type and shape of the irradiated object in the cabinet, etc. There may be a region in which not only the microwave intensity distribution but also the vibration direction is biased. On the other hand, when the microwave is received by the antenna, the antenna receives only the microwave vibration component in the same direction as the antenna. Therefore, when there is no microwave vibration component vibrating in the direction of the antenna in the vicinity of the antenna, the microwave energy cannot be concentrated on the antenna and the gas vent hole cannot be opened in the container.

The present invention has been made to solve the above-mentioned problems. Even when there is a region in which the micro-vibration direction is biased in the microwave oven, the lid of the hermetically sealed container is rapidly heated in a short time to ensure a proper temperature. It is an object to provide a means for melt opening to a size.

[Means for solving the problem]

An antenna made of an electric conductor is attached to the lid body of a container sealed by a lid body made of an insulating flexible sheet, and the antenna is provided with a portion inclined by 3 ° or more with respect to the bottom surface of the container. The microwave is concentrated at a specific location, and when the container is exposed to microwaves in a microwave oven, the microwave energy collected by the antenna is converted into heat, and the heat opens the lid body. Antennas of various shapes can be used, but microwave energy is applied to the tip of the band-shaped antenna, to the tip facing portion of the C-shaped antenna, and to the portions where the antennas are close to each other in the case of a combination of a plurality of antennas. Are collected. The collected microwave energy can be converted into heat by a heating element laminated on the lid body, and can also be converted into heat by dielectric loss of the lid body. 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 ₃ (However, as a substance that generates heat due to magnetic loss
Ferrite represented by (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.

Further, the insulating flexible sheet as used 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, polyvinyl chloride-vinyl acetate copolymer, vinylidene copolymer, acetal resin, diallyl phthalate resin, fluorine resin and resins composed of multiple combinations of these Can be mentioned. As thermosetting plastics, urea resin, phenol resin,
Examples thereof include epoxy resins, melamine resins, urethane resins, xylene-formaldehyde resins, and resins composed of a combination of a plurality of these.

[Action]

A standing wave of microwaves stands in the microwave oven, but the shape of the microwave oven is a rectangular parallelepiped, and the microwaves reflected by the vertical and horizontal wall surfaces have vertical and horizontal vibration components. In some cases, one of the vertical and horizontal vibration components is strong and the other is weak. Since the bottom surface of the microwave receiving antenna of the present invention is in contact with the placing portion in the refrigerator in the state where the sealed container of the present invention is housed in the microwave oven cabinet, the antenna is inclined by 3 ° or more with respect to the placing section. Have. Therefore, the antenna has components in both vertical and horizontal directions with respect to the upper surface of the mounting portion (for example, with respect to the horizontal surface if the upper surface of the mounting portion is horizontal), and the vertical and horizontal components of the microwave standing wave are Even when only one of the two vibration components is strong and the other is weak, the microwave energy is always effectively concentrated to generate a strong electric field at the end. The concentrated microwave energy is converted into heat by the heating element or the lid body to melt and open the lid body.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. First
1 to 3 are diagrams showing a first embodiment of the present invention.
In the figure, reference numeral 1 denotes a lid main body made of an insulating flexible sheet, which is heat-sealed to a flange portion of a plastic container 2 for containing stored food. The lid body 1 has a band-shaped antenna 4 made of a conductor and an insulating flexible sheet 6
The laminated body consisting of is adhered. The heating element 5 is bonded to the lid body 1 at a position close to the end of the antenna 4. The insulative flexible sheet 6 is composed of two sheets partially adhered to each other, and the remaining portions are adhered to the lid body so as to extend in opposite directions, and the elastically attached portions extend vertically. There is. When supplied, the insulating flexible sheet 6 as shown in FIG.
Is pressed by the temporary lid 8 and bent horizontally,
When the temporary lid 8 is removed when cooking in the microwave, the state shown in FIG. 2 is obtained. In this state, the antenna 4 extends in the vertical and horizontal directions with respect to the bottom surface of the container 2. Therefore, even when only one of the vertical and horizontal vibration components of the microwave is strong, the antenna 4 effectively generates microwave energy as a heating element. 5 and the heating element 5 generates heat to melt and open the lid body.

Here, the heat generation principle will be described. When a conductor such as a piece of metal is introduced into the microwave region, eddy current flows because the microwave is reflected on the surface of the conductor, and if the surface resistance is large, heat is generated by resistance heating due to the eddy current, but the surface resistance is When it is small, both ends of the conductor become a strong electric field and act as if the microwave were concentrated. When a dielectric is present as the heating element 5 in this strong electric field, the heat quantity Q generated in the dielectric 5 is f for the microwave frequency, ε _r for the relative permittivity of the substance, and tan for the dielectric loss angle of the substance.
If δ, electric field strength is E, and constant is K, then Q = K × f × ε _r × tan δ × K ² , and the heat generation amount Q increases in proportion to the square of the electric field strength E. As a result, the heating element 5 rapidly heats the lid body 1 in a short time to open the vapor discharge hole of an appropriate size.

FIG. 4 is a side view of 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, and insulating flexible sheets 6'and 6 are laminated on the upper and lower sides of the antenna. The heat shrinkage rate in the longitudinal direction of the insulating flexible sheet 6'is larger than that of the insulating flexible sheet 6. A part of the laminated body thus formed is adhered to the lid body 1 made of an insulating flexible sheet by the adhesive layer 7. The heating element 5 is bonded to the lid body 1 at a position close to the end of the antenna 4. When this sealed container is heated in a microwave oven, the antenna 4 is bent as shown by the two-dot chain line in the figure due to thermal contraction of the insulating flexible sheet, and its direction has a vertical component with respect to the bottom surface of the container 2.

FIG. 5 is a side view of the hermetically sealed container according to the third embodiment of the present invention. Lid body 1 made of insulating flexible sheet
Is heat-sealed to the flange portion of the container 2 so as to be inclined at an angle α with the bottom surface of the container 2. It is preferable that α is 3 ° or more. The laminate of the conductive antenna 4 and the insulating flexible sheet 6 is bonded to the lid body 1 so that the longitudinal direction is the maximum inclination direction of the lid body 1. The heating element 5 is bonded to the lid body 1 at a position close to the end of the antenna 4. Also in this embodiment, the longitudinal direction of the antenna has both vertical and horizontal components with respect to the bottom surface of the container 2.

FIG. 6 is a side view of the hermetically sealed container according to the fourth embodiment of the present invention. Lid body 1 made of insulating flexible sheet
Is heat-sealed to the flange portion of the container 2. The laminated body of the conductor antenna 4 and the insulating flexible sheet 6 is adhered to both the lid body 1 and the side surface of the container 2. The heating element 5 is bonded to the lid body 1 at a position close to the end of the antenna 4. Also in this embodiment, the longitudinal direction of the antenna has both vertical and horizontal components with respect to the bottom surface of the container 2.

In the fifth embodiment of the present invention shown in FIGS. 7 and 8, laminates 14a and 14b of a band-shaped antenna and an insulating flexible sheet are used, and the laminate 14b is bonded to the entire lid body. However, a part of the laminated body 14a is adhered to the lid main body, and a portion not adhered to the lid main body extends in a direction perpendicular to the bottom surface of the container 2 due to elasticity of the laminated body itself. Microwave energy is collected between the stacks 14a and 14b where it is converted to heat by the dielectric loss of the lid body and melts and opens the lid body.

In the first to fourth embodiments described above, the antenna (conductor)
The heating element placed close to the heating element is designed to generate heat in a strong electric field. However, by disposing a plurality of antennas as in the fifth embodiment and generating a stronger strong electric field therebetween, the heating element is heated. It is also possible to melt and open the vapor discharge hole by heat generation due to the dielectric loss of the lid body itself without providing.

In the sixth embodiment of the present invention shown in FIGS. 9 and 10, laminated bodies 14a and 14b of a band-shaped antenna and an insulating flexible sheet are used, and the laminated body 14b is bonded to the entire lid body. The laminated body 14a is adhered to both the lid body 1 and the side surface of the container 2. Microwave energy is collected between the stacks 14a and 14b where it is converted to heat by the dielectric loss of the lid body and melts and opens the lid body.

In the seventh embodiment of the present invention shown in FIG. 11, a laminated body 14a of a C-shaped antenna and an insulating flexible sheet is used, and a part of the laminated body 14a is adhered to the lid body. The non-existing part is separated from the lid body by the elasticity of the laminate itself. The microwave energy is collected between both ends of the laminated body 14a, and is converted into heat by the dielectric loss of the lid body, and the lid body is melted and opened.

In the eighth embodiment of the present invention shown in FIG. 12, a laminated body 14a of a C-shaped antenna and an insulating flexible sheet is used, and the laminated body 14a adheres to both the lid body 1 and the side surface of the container 2. Has been done. The microwave energy is collected between both ends of the laminated body 14a, and is converted into heat by the dielectric loss of the lid body, and the lid body is melted and opened.

In the ninth embodiment of the present invention shown in FIG. 13, two band antennas and an insulating flexible sheet laminate 14b, 14 are provided.
The same laminated body 14a as b is used, and the laminated bodies 14b and 14b are entirely adhered to the lid body, but the laminated body 14a is partially adhered to the lid body and is not adhered. Is separated from the lid body by the elasticity of the laminated body itself. Microwave energy is collected between the stacks 14b, 14b and 14a where it is converted to heat by the dielectric loss of the lid body and melts and opens the lid body.

In a tenth embodiment of the present invention shown in FIG. 14, a laminate 14b, 14 of two strip antennas and an insulating flexible sheet is provided.
The same laminated body 14a as b is used, and the laminated bodies 14b and 14b are entirely adhered to the lid main body, but the laminated body 14a is adhered to both the lid main body 1 and the side surface of the container 2. . Microwave energy is collected between the stacks 14b, 14b and 14a where it is converted to heat by the dielectric loss of the lid body and melts and opens the lid body.

In the eleventh embodiment of the present invention shown in FIG. 15, a laminate 14b of a C-shaped antenna and an insulating flexible sheet, and a laminate 14a of a strip antenna and an insulating flexible sheet 14a.
The laminated body 14b is entirely adhered to the lid main body, but the laminated body 14a is partially adhered to the lid main body and the non-adhered portion is separated from the lid main body by the elasticity of the laminated body itself. It's getting away. The microwave energy is collected between the tips of the laminated body 14b and between the laminated bodies 14a, where it is converted into heat by the dielectric loss of the lid body and melts and opens the lid body.

In the twelfth embodiment of the present invention shown in FIG. 16, a laminated body 14b of a C-shaped antenna and an insulating flexible sheet, a laminated body 14a of a strip antenna and an insulating flexible sheet 14a.
While the laminated body 14b is entirely adhered to the lid body, the laminated body 14a is adhered to both the lid body 1 and the side surface of the container 2. The microwave energy is collected between the tips of the laminated body 14b and between the laminated bodies 14a, where it is converted into heat by the dielectric loss of the lid body and melts and opens the lid body.

Preparation of a sealed container similar to that of the first embodiment except that the sealed container according to the first to twelfth embodiments (the lid body is made of a laminate of polyester / nylon / polypropylene) and the longitudinal direction of the antenna is horizontal. 200g of red rice was sealed inside and placed in the center of National Microwave NE-M200 (500W, downward stirrer) and heated for 2 minutes. All of the examples were opened in 10 to 30 seconds, but there were cases where the antenna with the longitudinal direction being horizontal did not reach the full aperture.

The embodiment of the present invention is configured as described above, but the invention is not limited to this. For example, the combination of the antennas of the fifth to twelfth embodiments is used, and this is used as the lid main body of the third embodiment. May be entirely adhered to, or a heating element may be provided between the antennas where microwave energy is collected.

〔The invention's effect〕

As described above, according to the present invention, when the sealed container is placed in the microwave oven, the antenna provided in the sealed container has a portion inclined by 3 ° or more with respect to the bottom surface of the container. Since the antenna has both vertical and horizontal components in the chamber, the lid of the sealed container is heated rapidly in a short time even when there is a region where the microwave vibration direction is biased in the chamber of the microwave oven. Make sure the melt opening to the proper size.

[Brief description of drawings]

FIG. 1 is a plan view of a hermetically sealed container according to a first embodiment of the present invention, FIG. 2 is a side view of the hermetically sealed container of the same embodiment, and FIG. 3 is a sectional view of the hermetically sealed container of the same embodiment. FIG. 5 is a side view of a hermetically sealed container which is a second embodiment of the present invention, FIG. 5 is a side view of a hermetically sealed container which is a third embodiment of the present invention, and FIG. 6 is a fourth view of the present invention.
FIG. 7 is a side view of the hermetically sealed container of the fifth embodiment, FIG. 7 is a plan view of the hermetically sealed container of the fifth embodiment of the present invention, FIG. 8 is a side view of the hermetically sealed container of the same embodiment, and FIG. FIG. 10 is a plan view of a hermetically sealed container according to a sixth embodiment of the invention, FIG. 10 is a side view of the hermetically sealed container according to the same embodiment, and FIG. 11 is a perspective view of a hermetically sealed container according to a seventh embodiment of the present invention. Is a perspective view of the hermetically sealed container of the eighth embodiment of the present invention, FIG. 13 is a perspective view of the hermetically sealed container of the ninth embodiment of the present invention, and FIG. 14 is a hermetically sealed container of the tenth embodiment of the present invention. FIG. 15 is a perspective view of the hermetically sealed container according to the eleventh embodiment of the present invention, and FIG. 16 is a perspective view of the hermetically sealed container according to the twelfth embodiment of the present invention. 1 ... Lid body, 2 ... Container, 3 ... Preserved food, 4 ... Antenna,
5 ... Heating element, 6, 6 '... Insulating flexible sheet, 7 ...
Adhesive layer, 8 ... Temporary lid, 14a, 14b ... Laminated body of antenna and insulating flexible sheet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 62-271864 (JP, A) JP 61-69576 (JP, A) JP 61-173028 (JP, A) JP HEI 1- 267179 (JP, A) US Patent 4210674 (US, A)

Claims (10)

[Claims] 1. A container hermetically sealed by a lid body made of an insulating flexible sheet, wherein the lid body is provided with an antenna having a portion made of a conductor and inclined by 3 ° or more with respect to the bottom surface of the vessel. When the container is exposed to microwaves in a microwave oven, microwave energy is concentrated at a specific location around the end of the antenna, the energy is converted into heat, and the heat causes the antenna to open the lid body. A sealed container for microwave oven cooking, comprising: 2. A heating element for converting the microwave energy into heat is laminated on the lid main body in proximity to or connected to an end of the antenna, and the microwave concentrated by the heating element by the antenna. The sealed container for microwave oven cooking according to claim 1, wherein energy is converted into heat. 3. The sealed container for microwave oven cooking according to claim 1, wherein the microwave energy concentrated by the antenna is converted into heat by dielectric loss of the lid body. 4. The microwave cooking apparatus according to claim 1, wherein the antenna has a C-shaped expanded shape and concentrates the microwave energy between opposed tip portions. Sealed container. 5. The microwave cooking apparatus according to claim 1, wherein two or more antennas are combined and the microwave energy is concentrated at a position where these antennas are close to each other. Sealed container. 6. The sealed container for microwave oven cooking according to claim 2, wherein the antenna has a strip shape, and the heating element is laminated on the lid body so as to be close to or connected to an end of the antenna. . 7. The lid body is arranged horizontally, the antenna is laminated on an insulating flexible sheet, and a part of the insulating flexible sheet is adhered to the lid body and not adhered to the lid body. 7. The sealed container for microwave oven cooking according to any one of claims 1 to 6, wherein is biased by the elasticity of the insulating flexible sheet so as to separate from the lid body. 8. The lid body is arranged horizontally, and at least two types of insulating flexible sheets having different heat shrinkage rates are laminated on the antenna, and a part of the laminated body formed in this manner is the lid body. 7. The electronic device according to claim 1, wherein a portion which is not adhered to the lid main body is adhered to the lid main body and heated by a microwave oven so as to be separated from the lid main body by thermal deformation. Sealed container for range cooking. 9. When the container is placed with its bottom surface in contact with a horizontal plane, at least a part of the lid body is tilted by 3 ° or more from the horizontal plane, and the antenna is stacked in the tilted direction of the lid body. The sealed container for microwave oven cooking according to any one of claims 1 to 6, wherein the sealed container is for microwave oven cooking. 10. The sealed container for microwave oven cooking according to any one of claims 1 to 6, wherein the antenna is bonded to the lid body and the side wall of the container.