JP2001322684A - Packaging material for cooking by microwave oven and packaging bag using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging material for cooking by a microwave oven, which requires no use of a heat-generating sheet as an additional member for surface heating for the browning or the like of foodstuffs to be heated by a microwave oven. SOLUTION: The packaging material for cooking by a microwave oven is a film with a heat-generating member layer for the microwave oven, which is provided on one face of a heat-sealable polyester film having 10-30 μm in thickness. In this packaging material, the heat-sealable polyester film is of a co-extruding type, and a base layer is laminated on the heat-generating layer so as to cover the same. A packaging bag is formed by heat-sealing a heat- sealable polyester resin face of the packaging material for cooking by the microwave oven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material for microwave cooking which heats food in a microwave and browns it, and a packaging bag using the packaging material for microwave cooking.

[0002]

2. Description of the Prior Art In heating using a microwave oven, aluminum is vapor-deposited on a heat-resistant plastic film so that the surface of food or the like is particularly strongly heated so as to be browned or the surface is appropriately cured and heated to a crispy state. A heat generating sheet provided with a layer and a mixed vapor-deposited layer of aluminum and aluminum oxide is disclosed (Japanese Patent Publication No. 60-15548,
JP-A-4-68758). These heat generating sheets are placed in a microwave oven in a state in which they are in contact with food, and by irradiating high frequency, generate heat and can heat the surface of the food in contact more strongly than other parts. is there.

[0003]

However, since the heat generating sheet is flexible as it is and cannot stably come into contact with the portion of the food to be heated, it is conventionally attached to a rigid paperboard or the like to be packaged. To do so, it had to be inserted into a pouch or tray. In this case, only the surface in contact with the heat generating sheet is heated, and the other surfaces cannot be expected to be as effective as the contact surface. An object of the present invention is to provide a packaging material for microwave cooking that does not require the use of a separate heating sheet for surface heating such as browning in foods to be heated in a microwave.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a heat-sealing polyester film provided with a microwave heating element layer on one side, and the heat-sealing polyester film has a thickness of 10 to 30 μm. A microwave oven cooking packaging material, characterized in that the heat-sealable polyester film is a co-extrusion type, and that the base layer is laminated to cover the heating element layer. And a packaging bag obtained by heat-sealing the heat-sealable polyester resin surface of the packaging material for microwave cooking.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The packaging material for microwave oven cooking according to the present invention is a packaging material characterized by using a polyester film having heat sealing properties and providing a heating element layer. FIG. 1 is a sectional view of a layer structure showing an embodiment of the packaging material for microwave cooking of the present invention. FIG. 2 is a cross-sectional view of a configuration in which a base material layer is laminated on the packaging material for microwave cooking of the present invention. FIG. 3 shows an embodiment of a packaging bag using the packaging material for microwave cooking of the present invention, (a) a perspective view showing a state in which contents are sealed in the packaging bag, and (b) a packaged state. perspective view, a (c) X ₁ -X ₁ part cross-sectional view. FIG. 4 is a perspective view showing another embodiment of a packaging bag using the packaging material for microwave cooking according to the present invention.
(B) Conceptual sectional view showing a state in which the contents are stored, (c)
Y ₁ part enlarged view, an enlarged view (d) Y ₂ parts. FIG. 5 is an explanatory diagram of a form of a bag. A conventional method of setting a heating element used for microwave heating is to prepare a heating sheet separate from the hermetically sealed packaging material as a heating sheet, place contents to be heated on the heating sheet, It was a method of heating. At the time of heating, the sealed packaging bag was removed, and the food was placed on the heating sheet, or the heating sheet was laid in a tray, and an opening for sanity was provided in the sealed packaging material. It was high frequency heating inside. The present inventors have conducted intensive studies on a method of heating such as browning by high frequency using a microwave oven without using such a heat generating sheet and in a packaged state.
As shown in (a), it has been found that the problem can be solved by using a film in which a microwave heating element layer is provided on one side of a heat-sealable polyester film 2 as the hermetically sealed packaging material. It has arrived.

The heat-sealable polyester film in the packaging material for microwave cooking according to the present invention may be a film made of a polyester resin which can be heat-sealed by a heat-sealing condition in a bag-making seal or a tray lid seal. The polyester resin,
For example, aliphatic diols and / or cycloaliphatic diols
A polyester resin other than polyethylene terephthalate derived from a diol component containing at least 80 mol% and a dicarboxylic acid component containing at least 50 mol% of terephthalic acid, and at least 50 mol% of the dicarboxylic acid component is terephthalic acid, The diol component is ethylene glycol 40-90
Mole% of ethylene oxide adduct of bisphenols
A polyester resin or the like containing 97 to 50 parts by weight of a copolymerized polyester composed of 10 to 60 mol% and 3 to 50 parts by weight of an epoxy group-containing ethylene copolymer can be used.

In the present invention, a heating element may be formed on the single film of the heat-sealable polyester. However, as shown in FIG. 1B, the heat-sealable polyester film is combined with the heat-sealable polyester resin. It is preferable to form a co-extruded film with a hydrophilic resin.

Examples of the heat resistant resin include resins such as polyethylene terephthalate, polycarbonate, polyacetal, polyamide, polyacetal, and polyimide. And in the co-extrusion film formation of these heat-resistant resin and the heat-sealable polyester resin,
Although not shown, a three-layer coextruded film including an adhesive layer between the heat-resistant resin and the heat-sealable polyester resin may be used.

The thickness of the heat-sealing resin layer of the heat-sealing polyester film is 10 to 30 μm.
It is desirable that Heat sealable resin layer is 10μ
If it is less than m, poor sealing may occur in the hermetic seal. The heat-sealing resin layer has a thickness of 30 μm.
If it exceeds m, it takes a long time for heat sealing, and the production efficiency is reduced.

As a means for providing a microwave heating element (hereinafter referred to as a heating element or a heating element layer) on the heat-sealable polyester film, a conventionally known method such as vacuum deposition, sputtering, or ion plating can be used. The microwave heating element layer is not particularly limited as long as it is a substance that generates heat by microwaves, but is preferably an aluminum deposited layer, a mixed deposited layer of aluminum and aluminum oxide, or ITO.

[0011] The packaging material for microwave cooking of the present invention includes:
As shown in FIG. 2A or 2B, it is desirable to laminate the base material 6. By laminating the base material 6, the heating element layer is protected, and it is possible to add a mechanical strength required as a packaging material or a protection function of the contents such as moisture proofness. In addition, it is preferable to perform printing required for a product on a substrate. As the substrate 6, a heat-resistant plastic film, polyethylene terephthalate,
Nylon, polypropylene, polymethylpentene, polycarbonate and the like can be used. In addition, paper,
A nonwoven fabric or the like may be used. When paper or non-woven fabric is used as the base material, it is preferably about ²⁰ to 100 g / m ² . *laminate

For laminating the packaging material for microwave cooking and a substrate, known methods such as a dry lamination method, a sandwich lamination method using a heat-adhesive resin as an adhesive layer, and a wet lamination method can be used.

When the contents are packaged using the packaging material for microwave cooking described above, the form of packaging is not limited. For example, the packaging material for microwave cooking of the present invention can be used in a bag type or a tray type as a usual packaging form. As the bag type, there is a pillow type bag 10 as shown in FIG. 3 (a). By filling the contents 10 into the bag 10 and sealing it as shown in FIG. 3 (b), FIG. As shown in (c), the bag (packaging material for microwave cooking) adheres to the surface Fs of the content. When it is desired to heat the entire surface of the food, vacuum packaging is preferred. By contacting the entire surface of the contents with the microwave cooking packaging material,
It can brown or crispy the food.

The packaging material for microwave cooking of the present invention includes:
The base material layer can be laminated as described above, and in particular, in the case of a packaging material in which the base material layer is laminated, it can be used as bags of various forms. The packaging material for microwave cooking of the present invention can be made into bags of various types as shown in FIGS. 5 (a) to 5 (h). Incidentally, the form of the bag illustrated in FIG. 3 is the pillow type shown in FIG. 5 (h).

The packaging material for microwave cooking of the present invention can be used for a tray container as shown in FIG. 4 (a) or 4 (b). As a tray container, FIG.
As shown in the figure, the tray comprises a molding tray 21 and a lid member 22.
The layer configuration of the forming tray 21 is, for example, as shown in FIG. 4D, the packaging material for microwave cooking of the present invention laminated on a plastic sheet 8 having moldability with its heating element layer as a laminate surface. The formed sheet is formed by means such as vacuum forming and pressure forming to form a concave portion for storing the contents, and after the contents are stored in the concave portion, covered with the lid member 22 and heat-sealed at the flange portion of the tray. It is to be sealed. In the present invention, a packaging material for microwave cooking can be used also for the lid material. FIG.
As shown in (c), the use of the microwave oven packaging material of the present invention in which the base material is laminated on the heating element layer allows the upper and lower surfaces Fs of the contents to be crispy,
In addition, the surface can be appropriately charred.

In the present invention, as described above, the contents are stored and sealed in a bag or a tray formed by using a packaging material for microwave cooking, and when heated, a steam escape is required if necessary. After forming the mouth, it is possible to make the surface of the food crispy or brown by simply storing it in a microwave oven and performing high-frequency heating under predetermined conditions. When using a conventional heating element,
Heating with a heating element to heat it by placing it under the content or on top of the content, heating only the surface that is in contact with the heating element, and if only one heating element is inserted The effect of only one side of the contents is obtained, but in the case of the present invention, the contents of the portion in contact with the bag or the tray are heated.

[0017]

Next, the packaging material for microwave oven cooking and the packaging bag using the same according to the present invention will be described in more detail with reference to examples. Example 1 Aluminum was applied to the homo-type resin layer surface of a two-layered co-extruded heat-sealable polyester film composed of a homo-type resin having a thickness of 12 μm and a copolymer-type resin by a vacuum evaporation method. 70
A heat generating layer was formed by vapor deposition to a thickness of 0 nm to obtain a packaging material for microwave cooking. Next, 50 g / m ² of thin paper was laminated on the surface of the packaging material on which the heating element layer was formed by a dry lamination method to obtain a packaging material example 1 of a packaging material for microwave cooking. Using the packaging material example 1, 125 mm x 160 mm
A pillow-type bag having a size of, a fried potato dough is stored therein, and the package is sealed to form a package example 1.
This was frozen. A part of the bag of the frozen packaged product of Example 1 was cut off with scissors and cooked in a microwave oven. The cooking conditions were as follows. Microwave oven: 500 watt Using a rotating table Heating time 3 minutes by thawing and heating The surface of the heated french fries was crispy and a good texture was obtained. Example 2 As a packaging material for microwave cooking, the surface of a heat-extrudable polyester film of a co-extrusion type (heat-resistant polyester resin layer 10 μm, heat-sealable polyester resin layer 10 μm, total thickness 20 μm) Aluminum is vacuum-deposited to a thickness of 700 nm, and 300 μm of polypropylene is laminated on the deposition surface as a moldable plastic sheet by a dry lamination method to form a molded sheet, and the molded sheet is formed using a pressure molding machine. Tray Example 2 was obtained by forming the concave portion to have a size of 70 mm × 150 mm and a depth of 30 mm, and setting the width of the flange portion to 10 mm. As the lid material, a co-extruded heat-sealable polyester film (heat-resistant polyester resin layer 10 μm, heat-sealable polyester resin layer 10 μm co-extruded film total thickness 10 μm)
m) Aluminum on the heat-resistant resin layer surface of 600 m
Was formed into a packaging material for microwave cooking by forming a heating element layer by vacuum evaporation to a thickness. A lid material example 2 was obtained by laminating a biaxially stretched polyester film 12 μm on the surface of the heating element layer by a dry lamination method. The meat pie was placed in the concave portion of the tray example 2, the cover material example 2 was covered, and the periphery was heat-sealed to obtain a package body example 2. The effect was confirmed by heating in a microwave oven (under the following conditions). Microwave oven: 500 w using a rotating table Heating time: 2 minutes The heated and baked meat pie was slightly browned on the front and back surfaces, and a finished product excellent in texture was obtained. Comparative Example 1 Biaxially stretched polyester film 1 of 12 μm
2 μm and 40 μm of the linear low-density polyethylene film were dry-laminated to obtain a packaging material comparative example 1. Separately, a heating element layer having a thickness of 700 nm is formed on one side of a heat-resistant polyethylene terephthalate film 12 μm by aluminum vapor deposition, and the surface of the heating element layer is bonded to 270 g / m ² of paperboard to have a size of 100 mm × 110 mm. Into a heat generating sheet. Using the packaging material comparative example 1, 125 mm ×
A pillow-type bag having a size of 160 mm was made (each having a seal width of 10 mm), and the heat-generating sheet and the fried potato dough were stored and sealed therein. Comparative Example 1 of frozen package
Was cut off with scissors and cooked in a microwave. The cooking conditions were as follows. Microwave oven: 500w Rotary table use Heating time 3 minutes by thawing and heating The surface of the heated french fries was crispy, and the contents that were in contact with the heating sheet had a crispy texture, but other parts In contrast to the texture described above, the overall heating was uneven. In addition, it was confirmed that the cost required for preparing the heat generating sheet and charging in the bag was increased and the definition was reduced. [Comparative Example 2] Using a compressed air molding machine, polypropylene as a moldable plastic sheet having a thickness of 300 µm and a concave portion of 70 was used.
A tray comparative example 2 was obtained by molding with a size of mm × 150 mm and a depth of 30 mm and a width of the flange portion of 10 mm. As the lid material, a biaxially stretched polyester film 12 μm and a copolymer type cast polypropylene film 5
0 μm was dry-laminated to obtain a lid material comparative example 2.
Separately, heat-resistant polyethylene terephthalate film 12
A heating element layer having a thickness of 600 nm was formed on one side of aluminum having a thickness of 600 nm by aluminum vapor deposition.
² and cut into a size of 100 mm × 110 mm to obtain a heat generating sheet. The heating sheet was laid in the recess of the tray comparative example 2, and the meat pie was placed thereon,
The lid material Comparative Example 2 was covered, and the periphery was heat-sealed to obtain a packaged body example 2. The effect was confirmed by heating in a microwave oven (under the following conditions). Microwave oven: 500 w using rotating table Heating time: 2 minutes The back side of the heated meat pie was slightly burnt, but the surface was too soft.

[0018]

According to the packaging material for microwave oven cooking of the present invention, food can be sealed and packaged for distribution. When heating in a microwave oven without using a heating sheet, which was conventionally made as a separate body, when heating in a microwave oven as it is (although a steam escape part is formed if necessary) as a package, Can be browned or crispy.

[Brief description of the drawings]

FIG. 1 is a sectional view of a layer constitution showing an embodiment of a packaging material for microwave cooking of the present invention.

FIG. 2 is a cross-sectional view of a configuration in which a base material layer is laminated on the packaging material for microwave cooking of the present invention.

FIG. 3 shows an embodiment of a packaging bag using the packaging material for microwave cooking of the present invention, (a) a perspective view showing a packaged state,
(B) a X ₁ -X ₁ part cross-sectional view.

4 (a) is a perspective view showing a packaging state, and FIG. 4 (b) is a conceptual sectional view showing a state in which contents are stored, showing another embodiment of a packaging bag using the packaging material for microwave cooking of the present invention. It is. (C) Y ₁ part enlarged view, an enlarged view (d) Y ₂ parts.

FIG. 5 is an explanatory view of a form of a bag.

[Explanation of symbols]

 P Package F Contents FS Surface of contents in contact with packaging material 1. Packaging material for microwave cooking 2. Heat-sealable polyester film Heat-sealable polyester resin layer 4. Heat resistant resin layer 5. Heating element layer 6. Base material layer 7 Adhesive layer 8 Molded base material sheet 10 Bag 11 Seal part 12 Back adhering part 13 Opening 20 Tray pack 21 Tray main body 22 Lid material 23 Depression 24 Flange part 25 Molded sheet

 ──────────────────────────────────────────────────続 き Continued on front page F-term (reference) DA20 EH20 EH66B GB15 JG05B JL05 JL12A YY00A

Claims (4)

[Claims] 1. A film comprising a heat-sealable polyester film provided with a microwave heating element layer on one side,
The heat-sealing polyester film has a thickness of 10 to 30 μm. 2. The packaging material for microwave cooking according to claim 1, wherein the heat-sealable polyester film is of a co-extrusion type. 3. The packaging material for microwave cooking according to claim 1, wherein a base material layer is laminated so as to cover the heating element layer. 4. A packaging bag obtained by heat-sealing a heat-sealable polyester surface of the packaging material for microwave cooking.