JP2796066B2 - Food packaging for microwave cooking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package such as a packaging bag or a packaging container for packaging foods cooked by using a microwave oven.

[0002]

2. Description of the Related Art With the spread of microwaves, foods in which food is sealed in a packaging bag or a packaging container made of a heat-resistant material so that the food can be cooked as it is by a microwave oven, Due to its simplicity, in recent years, the production volume has been increased and the types thereof have been diversified. In this kind of food,
The contents are completely sealed when the contents are prepared at the factory and packed in bags or packed in containers to prevent contamination by bacteria during transportation and display at stores, but the sealed food is kept as it is. When heated in a microwave oven, water vapor is generated in the bag or the container, and the vapor pressure causes the cover sheet portion of the bag or the container to burst. Therefore,
Prior to or during heating, a hole was made in the bag to release steam, or a part of the cover sheet portion was peeled off from the container. However, since it is troublesome to open a hole in each bag or peel off a part of the cover sheet portion, it is difficult to form a hole for vapor release naturally on the bag surface or the cover portion of the container when heated. Has been devised.

[0003] For example, Japanese Patent Application Laid-Open No. Sho 62-271864 discloses that in a hermetically sealed container in which a lid body is mainly sealed by a lid made of thermoplastic plastic, conductive powder such as metal powder or carbon powder is coated on the outer surface of the lid body. A locally formed printed film having a small circular shape or the like, or a conductive vapor-deposited film made of aluminum, chromium, tin oxide, indium oxide, etc., is formed with a conductive paint containing magnetic powder containing magnetic powder such as ferrite. When the closed container is placed in a microwave oven, the printed film or the conductive vapor-deposited film is rapidly heated, and the lid body of the portion where the printed film or the vapor-deposited film is formed is melted. In addition, a technique has been disclosed in which a perforated portion for vapor release is formed in a lid. Also, JP-A-63-30
Japanese Patent No. 7085 discloses that a sheet having a layer of indium oxide, aluminum, nickel, tin or the like which generates heat by microwaves on a base film is provided with an adhesive so as to close a hole for allowing water vapor to escape in the container. Discloses a food package for cooking in a microwave oven. Further, in Japanese Utility Model Laid-Open No. 1-116186, a predetermined position of a heat-resistant packaging material having heat bonding property is thermally bonded to an inner surface, and a conductive material such as aluminum is sandwiched in a part of the heat bonding portion. There is disclosed a microwave oven package in which when heated in a microwave oven, the adhesive strength of a heat-bonded portion having a conductive material interposed therebetween decreases with an increase in temperature, thereby preventing an increase in internal pressure.

[0004]

However, as disclosed in Japanese Patent Application Laid-Open No. Sho 62-271864, a printed film is locally applied to the outer surface of a lid body made of a thermoplastic plastic with a conductive paint or a magnetic paint. In a closed container having a configuration in which a perforated portion is formed or a conductive vapor-deposited film is locally formed, a large amount of heat is required to form a perforated portion penetrating through the lid main body, and the perforated portion is formed in the lid main body. It can be conceived that it takes a long time to perform effective steam release. Further, as disclosed in JP-A-63-307085, a hole for vapor release is previously provided in a container, and the hole is closed by sticking a sheet having a layer of a material which generates heat by microwaves. The food package having the above-described configuration requires a process of forming a hole in a container and a process of attaching a sheet for closing the hole, and has a problem that the number of steps is increased and the manufacturing process is complicated. Further, as disclosed in Japanese Utility Model Laid-Open Publication No. 1-116186, in a package having a structure in which a conductive material is sandwiched between a part of a heat bonding portion of a packaging material, a steam vent is formed in the heat bonding portion. In order to form the deaeration passage, a large amount of heat is required, and there is a problem similar to that of the closed container disclosed in Japanese Patent Application Laid-Open No. 62-271864.

[0005] A package is formed by using a sheet material composed of a multilayer film, and an opening is formed in advance in the innermost film of the sheet material, so that the outer layer film and the innermost film are separated from each other. There is also a method in which degassing is performed through a gap to prevent the package from being ruptured during cooking by heating in a microwave oven. However, in this method, it is necessary to form an opening portion in the innermost film in advance, so that the processing step is troublesome, and since there is an opening portion in the packaging material, the package body is not the same as the contents. It cannot be used for packaging foods or liquids whose contents require strict shielding from the outside air.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it has been found that through-holes are formed relatively quickly in a part of a packaging material by heating with a microwave oven, so that effective vapor release is performed. It is an object of the present invention to provide a package of food for microwave cooking that has a relatively simple manufacturing process and can completely seal the contents.

[0007]

The invention according to claim 1 is
The present invention relates to a package formed in a bag shape by bonding peripheral portions of a sheet material to each other, and the invention according to claim 2 covers an opening surface of the container by covering an opening surface of the container with the sheet material. The present invention is directed to a package in which a portion and a peripheral portion of a sheet material are bonded to each other. In the invention according to claim 1, the sheet material constituting at least one surface of the bag, and in the invention according to claim 2, the sheet material constituting the cover part of the container is referred to as an inner film and an outer film, respectively. In the invention according to claim 1, the two films are partially laminated to the sheet material so that the sheet material does not adhere to the peripheral portion of the sheet material except for the bonded portion. Forming a deaeration passage that extends to the edge and opens, and in the invention according to claim 2, the sheet material includes:
By not partially bonding the two films, a deaeration path is formed that extends from a portion other than an adhesive portion between the peripheral portion of the opening surface of the container and the peripheral portion of the sheet material to the edge of the sheet material and opens. . And at any position on the outer surface side of the inner film, corresponding to the formation portion of the deaeration path,
Heat was generated by microwave irradiation, and a part of the inner film was melted to attach a conductive material for forming a through hole in the inner film.

[0008]

According to the first and second aspects of the present invention, when the food packaged and sealed by the microwave oven is cooked by a microwave oven, the inner film of the laminated film forming the sheet material is formed. The conductive material attached to the outer surface side generates heat by the irradiation of the microwave, and the temperature of the portion rises, so that a part of the inner film is melted and a hole is formed in the inner film. The inside of the bag or the inside of the container and the deaeration path communicate with each other through the through-hole, so that the steam generated by heating the contents passes through the through-hole from the inside of the bag or the inside of the container to the sheet material. Flows out to the deaeration path formed between the inner film and the outer film of the sheet material, and further flows out through the opening at the edge of the sheet material through the deaeration path. By degassing in this manner, an increase in the internal pressure inside the bag or inside the container during heating and cooking can be suppressed. Then, the inner film of the laminated film forming the sheet material is formed to be thinner than the outer film and is formed of a material which is easily melted, so that the inner film is easily melted and the through holes are easily formed. By doing so, through holes are quickly formed in the inner film, and deaeration is performed smoothly.

[0009]

Preferred embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show one embodiment of the invention according to claim 1, FIG. 1 is a plan view of a packaging bag for food for cooking microwave oven, and FIG. FIG. 3 is a partially enlarged view of a vertical section taken along line III-III of FIG. In these figures, illustration of the contents is omitted.

The packaging bag includes two sheets of front and back sheets 10,
12 are superimposed on each other, and the peripheral portions of both sheet materials 10 and 12 are thermally bonded to each other so that both sheet materials 10 and 12
Is formed in a bag shape having a housing portion 16 surrounded by each inner surface of the above and the heat bonding portion 14. Then, the contents are stored in the storage section 16 and sealed. In this packaging bag, the sheet material 10 on the front side is composed of the outer film 18 and the inner film 20.
Are laminated and bonded to each other. Also,
The outer film 18 and the inner film 20 forming the front sheet material 10 are left unbonded in a strip shape so as to cross in the left-right direction. Deaeration path 2 opened at each
The two ends are deaeration ports 24.
Then, a conductive material 26 is adhered in a small circular shape on the outer surface side of the inner film 20 at a position corresponding to the formation portion of the deaeration passage 22 by a method such as printing or vapor deposition.

The sheet members 10 and 12 are formed of, for example, a synthetic resin film such as polyethylene, polypropylene, nylon and polyester. In addition, the conductive material 26
As, for example, indium oxide, aluminum, tin,
Nickel, carbon and the like are used. Note that the outer film 18 and the inner film 2 forming the front side sheet material 10 are formed.
0 is the same type of synthetic resin film, the inner film 20 is formed to be thinner than the outer film 18, and when the outer film 18 and the inner film 20 are different types of synthetic resin films, the inner film is The film 20 is made of a material that is easier to melt at a lower temperature than the outer film 18.

When the food sealed in the packaging bag having the above structure is placed in a microwave oven and cooked, the conductive material 26 attached to the outer surface of the inner film 20 of the sheet material 10 on the front side is converted into a microwave. Heat is generated by the irradiation, and the temperature of the portion locally increases in a short time. Then, a part of the inner film 20 is melted by the heat, and FIG.
As shown in FIG. 5, the through holes 28 are formed in the inner film 20, and the conductive material 26 is burned off. At this time, the contents are heated to generate water vapor inside the bag, and this water vapor flows into the deaeration passage 22 from the inside of the bag through the through hole 28 formed in the inner film 20, and The air is discharged from the bag through the deaeration port 24 through the inside of the bag 22. By performing degassing from the inside of the bag in this way, an excessive increase in the internal pressure inside the bag during heating and cooking is suppressed, and bursting of the bag is prevented.

FIG. 5 is a partially enlarged longitudinal sectional view of a packaging container for food for microwave cooking, showing one embodiment of the second aspect of the present invention. Note that illustration of the contents is omitted in this figure.

In this packaging container, the entire upper opening surface of the container body 30 having an open upper surface is completely covered with a cover sheet material 32 made of a synthetic resin film such as polyethylene, polypropylene, or nylon. The peripheral portion 34 of the surface and the peripheral portion of the cover sheet material 32 are bonded by an adhesive or thermally bonded, and the contents are sealed inside the container. The cover sheet material 32 has the same configuration as the sheet material 10 on the front side of the packaging bag described above. That is, the cover sheet material 32 is formed of the outer film 36.
And the inner film 38 are laminated and adhered to each other. The outer film 36 and the inner film 38 are not shown, but are not partially adhered in a strip shape. A deaeration passage 40 opened at the edge is formed.
Is a deaeration port 42. Then, a conductive material 44 such as indium oxide, aluminum, tin, nickel, or carbon is locally applied to a position corresponding to a portion where the degassing passage 40 is formed on the outer surface side of the inner film 38 by a method such as printing or vapor deposition. Is attached.

When the food sealed in the packaging container having the structure shown in FIG. 5 is placed in a microwave oven and cooked, the food adheres to the outer surface of the inner film 38 of the cover sheet material 32 as in the case of the above-mentioned packaging bag. The heated conductive material 44 generates heat due to the irradiation of microwaves, and the temperature of that portion locally rises in a short time, and the heat causes the inner film 38 to be heated.
When a part of is melted, through holes 46 are formed in the inner film 38 and the conductive material 44 is burned off as shown in FIG. Then, through the through-holes 46 formed in the inner film 38, the steam generated inside the container due to the heating of the contents flows from the inside of the container into the deaeration path 36,
The air passes through the inside of the deaeration passage 36 and is discharged from the deaeration port 42 to the outside of the container. By being degassed outside the container in this way,
The rise of the internal pressure inside the container during the heating and cooking is suppressed, and the rupture of the cover sheet material 32 is prevented.

The packaging bags and packaging containers according to the first and second aspects of the present invention are configured as described above.
Is not limited by the above description and the contents of the drawings, and may include various modifications without departing from the scope of the invention. For example, the invention according to claim 1 can be applied to various types of packaging bags such as a gusset bag and a standing pouch, and the shape, position, and the like of the deaeration path are not limited to those in the illustrated example. . In addition, the position, area, and number of conductive materials to be formed may be arbitrarily determined. By setting them variously, the steaming effect and prevention of steaming of the contents can be controlled to some extent. become. Further, the material of the sheet material and the type of the conductive material are not limited to those described above.

[0018]

Since the inventions according to the first and second aspects are constructed and operate as described above, when the packaging bag and the packaging container according to the first and second aspects are used, When the food sealed in the packaging bag or packaging container is heated and cooked in a microwave oven, a part of the packaging material is relatively quickly formed with a through-hole so that effective steam release can be performed. Further, the rupture of the cover sheet portion of the bag or the container can be effectively prevented. Further, the manufacturing process of the packaging bag or the packaging container is relatively simple. The packaging bag and the packaging container have a strict shut-off property between the contents and the outside air.

[Brief description of the drawings]

FIG. 1 is a plan view of a packaging bag for food for microwave cooking, showing one embodiment of the invention according to claim 1;

FIG. 2 is a partially enlarged view of a vertical cross section taken along line II-II of FIG.

FIG. 3 is a partially enlarged view of a vertical section taken along line III-III of FIG. 1;

4 is a partially enlarged longitudinal sectional view showing a state in which a through hole is formed in an inner film of a sheet material of the packaging bag shown in FIG. 1;

FIG. 5 is a partially enlarged longitudinal sectional view of a packaging container for food for microwave cooking, showing one embodiment of the invention according to claim 2;

6 is a partially enlarged longitudinal sectional view showing a state in which a through-hole is formed in an inner film of a cover sheet material of the packaging container shown in FIG. 5;

[Explanation of symbols]

 10, 12 sheet material 14 thermal bonding portion of sheet materials 10, 12 18 outer film of front sheet material 20 inner film of front sheet material 22, 40 deaeration path 24, 42 deaeration ports 26, 44 conductive material 28 , 46 through-hole 30 container body 32 cover sheet material 36 outer film of cover sheet material 38 inner film of cover sheet material

Claims (2)

(57) [Claims] 1. A package for a microwave cooking food in which peripheral portions of a sheet material are adhered to each other to form a bag, and a food is enclosed therein, wherein a sheet material constituting at least one surface of the bag is formed. An inner film and an outer film are laminated and bonded to each other to form a sheet material. By not partially bonding the two films to the sheet material, the end of the sheet material is removed from a portion excluding the bonded portion at the peripheral edge of the sheet material. A deaeration path extending to the edge and opening is formed, and a portion of the inner film that is heated by microwave irradiation and is heated at any position corresponding to a portion where the deaeration path is formed on the outer surface side of the inner film. A food package for microwave cooking, characterized in that a conductive material for forming a through hole in the inner film by adhering to the inside film is adhered. 2. A package for food for cooking microwave oven, wherein an opening surface of the container is covered with a sheet material, a peripheral portion of the opening surface of the container is adhered to a peripheral portion of the sheet material, and a food is enclosed therein. The sheet material is formed by laminating an inner film and an outer film and bonding them to each other, and by not partially bonding the two films to the sheet material, the opening surface periphery of the container and the sheet material are formed. Along with forming a deaeration path that extends from a portion excluding the adhesive portion with the peripheral portion to the edge of the sheet material and opens, the outer surface side of the inner film,
A conductive material that generates heat by microwave irradiation and melts a part of the inner film to form a through hole in the inner film is attached to any position corresponding to a portion where the degassing path is formed. Packaging of food for microwave cooking.