JP4242872B2 - How to open a microwave packaging container - Google Patents

Description

The present invention is a packaging container foods are filled, still in its packaging container without removing the foods can be heated in a microwave oven for microwaves electricity which can prevent rupture of the package due to the rise in internal pressure due to heat The present invention relates to a method for opening a packaging container.

Conventionally, when heating a packaging container filled with food or the like in a microwave oven, in order to suppress an increase in internal pressure due to heating, a part of the lid of the packaging container is manually opened in advance to form a steaming port In addition, by expelling the steam to the outside, the rise in the internal pressure was suppressed (relief pressure) to prevent the rupture of the packaging container.

However, when manually opening the lid, variation occurs in the size of the formed mouth, and if the mouth is too large, the amount of water loss of food increases and the taste becomes poor. If the fume throat is too small or if you forget to open it, there is a problem that sufficient pressure cannot be released and the internal pressure rises, the packaging container bursts, and the contents scatter.

Further, as another conventional example, an annular cut portion is provided in the flange portion of the container body, and the annular cut portion and the inner edge of the heat seal portion are separated from each other, thereby having a pressure resistance against peeling of the lid material when the internal pressure increases. There is also a packaging container that can be used (Patent Document 1). When this packaging container is heated in a microwave oven, the packaging container is ruptured, or even when the rupture does not occur, high-temperature and high-pressure steam is used when the lid is opened. May cause burns and so on.
Japanese Patent Publication No. 5-67509

The present invention has been made to solve the above-described problems, and even when a packaging container filled with food or the like is heated in a microwave oven, by releasing the internal pressure increased by heating from a predetermined site, packaging container is ruptured contents may splash defect and is intended to provide a opening method of electronic range for packaging containers can be prevented or burns.

According to a first aspect of the present invention , there is provided a container main body formed by laminating a plurality of layers, and having a flange portion at the periphery of the opening, and closing the opening of the container main body. A microwave packaging container provided with a film-like lid material heat-sealed at a portion, and a heat-sealed portion heat-sealed at the flange portion, and the flange portion from an inner edge of the heat-sealed portion An annular notch provided inside the container body;
An easily peelable portion provided in the annular cut portion , wherein the distance between the annular cut portion and the inner edge of the heat seal portion is smaller than the other portion of the annular cut portion in a part of the annular cut portion; The peeling force of the easy peeling part is smaller than the peeling force of the heat seal part so that the easy peeling part peels to form a vapor discharge port due to an increase in internal pressure of the packaging container for microwave oven. The easy peeling part peels off by heating in a microwave oven to form the vapor discharge port, and after forming the vapor discharge port, the heat seal part is left on the lid material side, It is the opening method of the packaging container for microwave ovens peeled from the said container main body.

According to a second aspect of the present invention , there is provided a container body having a flange portion at the periphery of the opening, and storing a plurality of layers that close the opening of the container body and are heat-sealed by the flange portion. A microwave-type packaging container having a film-shaped lid material formed by the heat sealing portion heat-sealed by the flange portion, and the lid material from the inner edge of the heat-sealing portion. a notch portion of the annular provided inwardly of wood, provided the notch portion of the annular, the annular distance between the inner edge of said annular notch portion the heat-sealed portion in some cuts of the annular An easy peeling part smaller than the other part of the notch part, and the easy peeling part is peeled off to form a vapor outlet by increasing the internal pressure of the microwave packaging container. Before peeling force The peeling force of the heat seal part is smaller than that, and the easy peel part is peeled off by heating in a microwave oven to form the vapor discharge port, and after forming the vapor discharge port, the heat seal part is formed in the container body. It is the opening method of the packaging container for microwave ovens which leaves on the side and peels the said cover material from the said container main body.

According to a third aspect of the present invention , there is provided the microwave packaging container opening method according to the first or second aspect , wherein the peeling force between the flange portion and the lid member at a part of the annular cut portion is 1 N / It is the opening method of the packaging container for microwave ovens which is 15 mm-18N / 15mm.

The means which concerns on Claim 4 is the opening method of the packaging container for microwave ovens of any one of Claims 1-3, Comprising: The peeling force of the flange part and cover material in a part of cyclic | annular cut | notch part Is the opening method of the packaging container for microwave ovens which is 60% or less of the peeling force of the flange part and cover material in the other part of a cyclic | annular cut | notch part.

The means according to claim 5 is the method for opening a packaging container for microwave oven according to any one of claims 1 to 4, wherein the container main body or the lid member on the outer surface of a part of the annular cut portion. It is the opening method of the packaging container for microwave ovens provided with the display indicating that it is a steam outlet.

According to invention of Claim 1 , it is a flange part of a container main body, Comprising: The cyclic | annular cut | notch part provided inside the container main body from the inner edge of the heat seal part, and this cyclic | annular cut | notch part and heat seal part of Because there is an easy peeling part smaller than the other part of the annular cut part at a part of the annular cut part, and the peeling force of the easy peel part is smaller than the peeling force of the heat seal part. The easy peeling part peels off due to the increase of the internal pressure due to heating in the microwave and the steam can be discharged, and the high temperature and high pressure steam can be prevented from being ejected when the lid member is opened.

According to invention of Claim 2 , it is a lid | cover material, The cyclic | annular cut | notch part provided in the inner side of the lid | cover material from the inner edge of the heat seal part, and this cyclic | annular cut | notch part and the inner edge of a heat seal part A microwave oven is provided because an easy peeling portion smaller than the other portion of the annular cut portion is provided at a part of the annular cut portion, and the peeling force of the easy peel portion is smaller than the peeling force of the heat seal portion. The easy peeling part peels off due to the increase of the internal pressure due to heating in the steam, and the steam can be discharged, and the ejection of high-temperature and high-pressure steam can be prevented when the lid member is opened.

According to invention of Claim 3 , in addition to the effect of Claim 1 or Claim 2 , since the peeling force of the easy peeling part was made into the range of 1N / 15mm-18N / 15mm, the internal pressure by the heating in a microwave oven The easy peeling part will surely peel off against the rise, causing vapor discharge, preventing the packaging container from bursting and splattering the contents, and during normal handling such as transportation, There is no leakage.

According to invention of Claim 4 , in addition to the effect of Claims 1 thru | or 3 , the peeling force of the flange part in a part of cyclic | annular cut-in part and a cover material is a flange in the other part of a cyclic | annular cut-in part. Because the difference between the peel strengths of the part and the lid material is reduced to 60% or less and the difference between the two peel forces is increased, the other part of the annular notch does not peel, and the easy peel part is always part of the annular notch. It is possible to discharge the steam by peeling off, and the variation in the area of the steam discharge port is reduced, the variation in moisture loss is suppressed, and the texture and taste quality can be maintained at a certain level.

According to the fifth aspect of the invention, in addition to the effects of the first to fourth aspects, a vapor discharge port is provided on the outer surface of the container main body or the lid member in the easy peeling portion which is a part of the annular cut portion. By providing a sign to the effect, the cook can be informed that the part is hot due to the discharge of steam, and the packaging container can be grasped by avoiding the steam discharge port, so that burns can occur in advance. Can be prevented.

An embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a partially broken plan view of one embodiment of the present invention, and A shows a microwave packaging container. The microwave packaging container A includes a container body 1 having a flange portion 3 at the periphery 31 of the opening to store the contents (not shown) and a plurality of layers, and the container body 1. A film-like lid member 5 is provided which is sealed by the heat seal portion 4 of the flange portion 3. Further, the flange portion 3 has an annular cut portion 2 provided inward of the container body 1 from the inner edge 41 of the heat seal portion 4.

The container body 1 described above has a plurality of layers, for example, a three-layer cross section as shown in FIG. 3A. The sealant layer 11 and the easily peelable layer 12 (of the heat seal part 4) are formed from the inside of the container body 1. It has a multi-layer structure in which an easy peeling layer 12) having a weaker peeling force than the peeling force and a base material 13 are laminated in this order. This multilayer structure is produced by thermoforming a multilayer sheet formed by, for example, a coextrusion casting method, a heat laminating method, a dry laminating method, a coextrusion laminating method or the like into a container shape by vacuum forming or pressure forming.

The sealant layer 11 is a layer heat-sealed with the lid member 5, for example, a polyolefin resin such as polyethylene, polypropylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, polystyrene resin, polyamide resin, A polyester resin or a mixture of these resins is used.

The easy peeling layer 12 peels off when heated by a microwave oven to release pressure, or peels off the lid 5 from the container body 1 when opened. For example, polyethylene, polypropylene, ethylene-α-olefin copolymer, ethylene-acetic acid A polyolefin resin such as a vinyl copolymer, a polystyrene resin, a polyamide resin, a polyester resin, or a mixture thereof is used.

The base material 13 forms the structure of the container body 1. For example, a polyolefin resin such as polyethylene, polypropylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, polystyrene resin, polyamide resin, and polyester resin. A material such as a resin is used.

In addition, each material of the sealant layer 11, the easy peeling layer 12, and the base material 13 described above is selected and used from each group so that a predetermined peeling force can be obtained.

The annular cut portion 2 as shown in FIG. 1 and FIG. 2 is formed by, for example, pressing the cutting edge of a cutting tool, or forming an annular cut by laser processing, ultrasonic processing, or the like. The annular notch 2 is annularly provided inside the heat seal portion 4 along the circumferential direction of the flange portion 3, but the distance between the annular notch 2 and the inner edge 41 of the heat seal portion 4 is an annular notch. The part 2 a of the part 2 is an easily peelable part 6 that is smaller than the other part 2 b of the annular cut part 2. Although it is desirable that the depth of the annular cut portion 2 reaches the easy peeling layer 12 as shown in FIG. 3, the peeling of the easy peeling layer 12 is caused at the time of relief, and the lid 5 and the container body are opened at the time of opening. 1 may be shallow if it can be easily separated. Further, in FIG. 1 and FIG. 2, the portion 2 a of the annular cut portion 2 is configured to be close to the heat seal portion 4. However, as shown in FIG. 6, the portion 4 a of the heat seal portion 4 is connected to the container body 1. It is good also as a structure which is made to protrude inside and is close to the cyclic | annular cut | notch part 2. FIG.

The aforementioned lid material 5 is made of a material such as polyethylene, polypropylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, etc., in order to facilitate heat sealing with the sealant layer 11 of the container body 1. .

By the way, as shown in FIG. 3A, the distance between the part 2a of the annular notch 2 and the inner edge 41 of the heat seal part 4 is La, and as shown in FIG. When the distance between the other portion 2b of the cut portion 2 and the inner edge 41 of the heat seal portion 4 is Lb, the distance between the annular cut portion 2 and the inner edge 41 of the heat seal portion 4 is a part 2a of the annular cut portion 2. The reason why the structure is smaller than the other part 2b of the annular notch part 2 (La <Lb) is that the part 2a of the annular notch part 2 is easier to peel than the other part 2b of the annular notch part 2. This is because part 6 is used. That is, as shown in FIGS. 4A and 4B, when the internal pressure rises due to the heating of the contents by the microwave oven, the lid 5 swells and stress is concentrated at the position Pa of the inner edge 41 of the heat seal portion 4. However, the force applied to the position Qa depends on the distance between the position Pa where the stress is concentrated and the position Qa. The closer this distance is, the easier the separation from the position Qa occurs (FIG. 4A). The farther the position Qa is, the more difficult it is to peel off from the position Qa (FIG. 4B). And the multilayer structure of the container main body 1 is comprised so that the peeling force of the easy peeling part 6 may become smaller than the peeling force of the heat seal part 4. FIG. This is because the vapor discharge port is formed by peeling from the easy peeling portion 6 due to an increase in the internal pressure of the microwave packaging container A, and heating is performed by the inside and outside of the container body 1 communicating with each other through the vapor discharge port. The discharged steam is discharged.

In the above description, the cohesive delamination that causes the separation of the lid 5 and the container body 1 by breaking the delamination between the lid 5 and the container body 1 exclusively inside the easy peel layer 12 has been described. Instead, it may be a two-layer structure of the sealant layer 11 and the substrate 13 and may be delamination that causes delamination between the two layers, or may be a combined delamination of cohesive delamination and delamination. As an example of causing cohesive peeling, an easy peel material is used for the easily peelable layer 12, and as an example of causing delamination, resins having poor adhesion such as polypropylene resin and polyethylene resin are laminated adjacently. Or a method of adhering adjacent layers using a thermoplastic adhesive such as hot melt.

It is preferable that the peeling force between the flange portion 3 and the lid member 5 in the part 2a of the annular cut portion 2 which is the easy peeling portion 6 is in a range of 1 N / 15 mm to 18 N / 15 mm. If it is 18 N / 15 mm or less, it is necessary to cause peeling with an increase in internal pressure. The reason why it is 1 N / 15 mm or more is the contents during normal handling such as transportation, for example, when the packaging container A for microwave oven is transferred. This is to prevent the contents from leaking due to peeling due to the force of the flow of the liquid or peeling due to the force applied from the outside. As described above, the peeling force can be obtained by adjusting the projecting dimension of the part 2a of the annular cut portion 2 toward the heat seal portion 4 side. In addition, the above-mentioned peeling force is a value measured at a tensile speed of 300 mm / min according to JIS K 6854-1 (adhesive-peeling peel strength test method-part 1: 90 degree peel).

Further, the peeling force between the flange portion 3 and the lid member 5 in the part 2a of the annular cut portion 2 is 60% or less of the peeling force between the flange portion 3 and the lid member 5 in the other portion 2b of the annular cut portion 2. Preferably there is. Whenever the internal pressure rises by heating the microwave packaging container A in the microwave oven by increasing the difference in the peel force between the part 2a of the annular notch 2 and the other part 2b of the annular notch 2 This is to cause peeling at the part 2 a of the annular cut portion 2 that is the easy peeling portion 6, and no peeling occurs at the other portion 2 b of the annular cut portion 2.

When the lid 5 is separated from the container body 1 and opened after heating by the microwave oven, the position Pb is close because the distance between the stress concentrated position Pb and the position Qb where peeling occurs is short as shown in FIG. The force applied to is easily transmitted to the position Qb, and the lid 5 can be easily peeled off from the container body 1 and opened. Further, since the annular cut portion 2 is formed in an annular shape over the entire circumference of the flange portion 3, the lid member 5 and the container body 1 can be easily and reliably separated at the time of opening, and the annular cut portion 2 is beautiful along the annular cut portion 2. The lid can be peeled off.

Further, in Examples 1 to 3 to be described later, the outer diameter of the lid member 5 is made larger than the outer diameter of the flange portion 3 of the container body 1 to provide a grip allowance, but there is an obstacle to the opening of the lid member 5. If not, the outer diameters of both may be the same.

Next, Example 1 which is the first embodiment of the present invention described above is shown below. As shown in FIG. 1 to FIG. 5, Example 1 has a container body 1 having a three-layer structure and is provided with a sealant layer 11, an easy release layer 12 and a base material 13. It is an example which peels the container main body 1 and the cover material 5. FIG.

(Example 1)
[Container body]
Base material: Polypropylene resin (thickness: 730 μm)
Easy peeling layer: Blend resin (thickness) in which 70 parts by mass of CMPS VX-94 manufactured by Mitsui DuPont Polychemical Co., Ltd., 20 parts by mass of polypropylene resin, and 10 parts by mass of ethylene-α-olefin copolymer were mixed. 20μm)
Sealant layer: Polypropylene resin (thickness 50 μm)
The base material 13, the easily peelable layer 12 and the sealant layer 11 are formed into a sheet shape by the coextrusion casting method so that the thickness of each layer becomes the above value, and further, an inner diameter of 70 mm, a depth of 50 mm by a pressure forming method, A circular container body 1 having a flange width of 8 mm was produced. In addition, an annular cut portion 2 (another portion 2b of the annular cut portion 2) having a depth of 75 μm and a width of 0.5 mm is provided in the flange portion 3 1 mm outside from the inner edge 31 of the flange portion 3, and a flange as the easy peeling portion 6 is provided. An annular cut portion 2 (a part 2a of the annular cut portion 2) having a width of 15 mm and an overhanging dimension of 4 mm was provided toward the outside of the portion 3.
[Cover]: A biaxially stretched polyester film (thickness 12 μm), a biaxially stretched polyamide film (thickness 15 μm), and an unstretched polypropylene film (thickness 50 μm) are laminated by a dry laminating method so as to have the above thickness. did.
[Heat seal]
The container body 1 was covered with a lid material 5 and heat sealed with a width of 2 mm from the outer edge of the flange portion under the conditions of a seal temperature of 180 ° C., a pressure of 0.4 MPa, and a sealing time of 2 seconds.
[Peel test results]
When the peel force was measured, it was 12 N / 15 mm (La = 0.5 mm) in the part 2 a of the annular cut part 2 that is the easy peel part 6, and 37 N / 15 mm (Lb) in the other part 2 b of the ring cut part 2. = 4.5 mm).
[Practical test results]
120 g of consommed soup is placed in the container body 1 and covered with the lid 5 and heat-sealed under the above heat-sealing conditions, and then heated in a microwave oven with an output of 600 W. Only a part 2a of the cut portion 2 was peeled off, and it was possible to release the pressure well without a plosive sound or leakage of contents.

(Comparative Example 1)
A comparative packaging container was produced under the same conditions as in Example 1 except that the flange portion was not provided with a part 2a of the annular cut portion 2 that was the easy peeling portion 6, and a container body 1 and a lid were produced under the same conditions. The peeling force with the material 5 is 38 N / 15 mm (Lb = 4.5 mm), and in a similar test in which 120 g of consomme soup is put in the container body 1, the heat seal part 4 has a burst sound after heating 95 seconds. About 1/3 of the entire circumference peeled off, and the contents were blown out.

As described above, in Example 1, by forming the easy peeling portion 6 in the flange portion 3, even if the internal pressure in the microwave packaging container A heated by the microwave rises, the easy peeling portion 6 peels off. Since the inside and outside of the container body 1 communicate with each other and the steam is released, the pressure is surely released, and the contents can be cooked without causing the generation of a plosive sound or leakage of the contents.

Next, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 7A, this embodiment differs from Example 1 in that the container body 1 is not provided with the easily peelable layer 12 and has a two-layer structure of the sealant layer 11 and the base material 13. This is an example in which a vapor discharge port is formed to release pressure by delamination that causes delamination in the interlayer 14 with the base material 13. Example 2 which is the second embodiment of the present invention will be described below.

(Example 2)
[Container body]
Base material: Blend resin (thickness: 750 μm) in which 65 parts by mass of polypropylene resin, 20 parts by mass of ethylene-α-olefin copolymer and 15 parts by mass of low-density polyethylene resin are mixed.
Sealant layer: High density polyethylene (thickness 50μm)
The base material 13 and the sealant layer 11 are formed into a sheet shape by the coextrusion casting method so that the thickness of each layer becomes the above value, and further, a circular shape having an inner diameter of 70 mm, a depth of 50 mm, and a flange width of 8 mm by a pressure forming method. A microwave packaging container A was prepared. Similarly to the configuration shown in FIG. 7 (b), an annular notch 2 having a depth of 60 μm and a width of 0.5 mm is formed in the flange 3 that is 1 mm outside the inner edge 31 of the flange 3 (of the annular notch 2). The other part 2b) was provided, and the easily peelable part 6 was provided with an annular cut part 2 (a part 2a of the annular cut part 2) having a width of 15 mm and an overhanging dimension of 4 mm toward the outside of the flange part 3.
[Cover]: A biaxially stretched polyester film (thickness: 12 μm), a biaxially stretched polyamide film (thickness: 15 μm), and a linear low-density polyethylene film (thickness: 50 μm) were sequentially laminated by a dry laminating method.
[Heat seal]
The container body 1 was covered with a lid 5 and heat sealed with a width of 2 mm from the outer edge of the flange portion 3 under the conditions of a seal temperature of 170 ° C., a pressure of 0.4 MPa, and a sealing time of 2 seconds.
[Peel test results]
When the peel force was measured, it was 7 N / 15 mm (La = 0.5 mm) in the part 2 a of the annular cut part 2 that is the easy peel part 6, and 41 N / 15 mm (Lb) in the other part 2 b of the ring cut part 2. = 4.5 mm).
[Practical test results]
After 120 g of consomme soup was put in the container body 1 and covered with the lid 5 and heat-sealed under the above heat-sealing conditions, the microwave packaging container A was heated in a microwave oven with an output of 600 W. After 75 seconds of heating, Only a part 2a of the annular cut portion 2 as the easy peeling portion 6 was peeled off, and it was possible to release the pressure well without a bursting sound or leakage of contents.

As described above, in Example 2, by forming the easy peeling part 6 in the flange part 3, even if the internal pressure in the microwave packaging container A heated by the microwave rises, the base material of the easy peeling part 6 In the interlayer 14 between the sealant 13 and the sealant 11, the inside and outside of the container body 1 communicate with each other due to delamination, so that the vapor escapes. Can be cooked.

Next, a third embodiment of the present invention will be described with reference to FIGS. In this embodiment, peeling due to an increase in internal pressure is performed not on the container body 1 side but on the lid material 5 side, and the lid material 5 has a multilayer structure as shown in FIG. B is a microwave packaging container. This microwave packaging container B includes a container body 1 having a flange portion 3 at the periphery 31 of the opening and storing contents (not shown), and the container body 1. A film-like lid member 5 formed by laminating a plurality of layers that closes the opening and is heat-sealed by the flange portion 3 is provided. Further, as shown in FIG. 9, the lid member 5 has the annular cut portion 8 which is the lid member 5 and is provided inward of the lid member 5 from the inner edge 41 of the heat seal portion 4. The distance between the notch 8 and the inner edge 41 of the heat seal part 4 is such that the part 8a of the annular notch 8 forms an easily peelable portion 7 that is smaller than the other part 8b of the annular notch 8. Then, as in the case of the easy peeling part 6 of the container body 1 of Example 1, the peeling force of the easy peeling part 7 is made smaller than the peeling force of the heat seal part 4, and the internal pressure of the packaging container B for microwave oven is increased. Peeling is performed from the peeling unit 7 to form a steam discharge port, and the steam discharged from the container body 1 is discharged through the vapor discharge port. For example, as shown in FIG. 8, the above-described lid material 5 has a three-layer cross section, and the sealant layer 51 and the easy peeling layer 52 (with a peeling force weaker than the peeling force of the heat seal portion 4) from the container body 1 side. It has a multilayer structure in which an easy peeling layer 52) and a base material 53 are laminated in this order. In addition, since the constituent material in the lid | cover material 5, an effect, etc. are the same as the case of the container main body 1 of Example 1, detailed description is abbreviate | omitted. Hereinafter, Example 3 which is the third embodiment of the present invention will be described.

(Example 3)
[Container body]
Base material: Polypropylene resin (thickness 800 μm)
The base material 13 was formed into a sheet shape, and a circular container body 1 having an inner diameter of 70 mm, a depth of 50 mm, and a flange width of 10 mm was produced by a pressure forming method.
[Cover material]
Base material: A film obtained by laminating a biaxially stretched polyester film (thickness: 12 μm) and a biaxially stretched polyamide film (thickness: 15 μm) was used as the base material 53.
Easy release layer: Blend resin (thickness 20 μm) in which 70 parts by mass of CMPS VX-94 manufactured by Mitsui DuPont Polychemical Co., Ltd., 20 parts by mass of polypropylene resin, and 10 parts by mass of ethylene-α-olefin copolymer are mixed. )
Sealant layer: Polypropylene resin (thickness 30 μm)
The easy peeling layer 52 and the sealant layer 51 described above were produced by a coextrusion cast method, and a base material 53 was laminated to form a lid 5 by a dry lamination method. In addition, an annular cut portion 8 (the other portion 8b of the annular cut portion 8) having a diameter of 74 mm and a depth of 40 μm is provided on the heat seal surface side of the lid member 5, and the easily peelable portion 7 has a width of 15 mm toward the outside. An annular cut portion 8 (part 8a of the annular cut portion 8) having an overhanging dimension of 4 mm was provided.
[Heat seal]
Cover the container body 1 with the lid 5, align the center of the container body 1 with the center of the annular notch 8 of the lid 5, and seal the flange under the conditions of a seal temperature of 180 ° C., a pressure of 0.4 MPa, and a sealing time of 2 seconds. Heat sealing was performed with a width of 2 mm from the outer edge of part 3.
[Peel test results]
When the peeling force was measured, 15 N / 15 mm (the distance La between the portion 8 a of the annular cut portion 8 and the inner edge 41 of the heat seal portion 4... 0 mm) and 38 N / 15 mm (the distance Lb = 5.0 mm between the other portion 8 b of the annular cut portion 8 and the inner edge 41 of the heat seal portion 4) at the other portion 8 b of the annular cut portion 8.
[Practical test results]
After 120 g of consommed soup was put in the container body 1 and covered with the lid 5 and heat-sealed under the above heat-sealing conditions, the packaging container B for microwave oven was heated in a microwave oven with an output of 600 W. After 75 seconds of heating, Only a part 8a of the annular cut portion 8 which is the easily peelable portion 7 was peeled off, and it was possible to release the pressure well without a burst sound or leakage of contents.

(Comparative Example 2)
A comparative packaging container was produced with the same configuration and the same conditions as in Example 3 except that the lid member 5 was not provided with a part 8a of the annular cut portion 8 which is the easy peeling portion 7, and the container body 1 and The peeling force with the lid 5 is 38 N / 15 mm (distance Lb = 5.0 mm between the annular cut 8 and the inner edge 41 of the heat seal part 4), and a similar test in which 120 g of consomme soup is put in the container body 1 Then, about 1/3 with respect to the entire circumference of the heat seal part 4 was peeled off with a plosive sound after 100 seconds of heating, and the contents were blown out.

As described above, in Example 3, by forming the easy peeling part 7 on the lid member 5, even if the internal pressure in the microwave packaging container B is increased by the microwave oven, the steam is passed through the easy peeling part 7. Since it escapes to the outside, it is possible to reliably release pressure, and to cook the contents without generating a plosive sound or leaking the contents.

Note that the peeling force of the part 8a of the annular notch 8 which is the easy peeling part 7 and the peeling force of the other part 8b of the annular notch 8 are the inner edges of the heat seal part 4 as in the first and second examples. It can be adjusted to a predetermined value by changing the distance between 41 and the annular cut portion 8.

By the way, when the container main body 1 and the lid | cover material 5 are made into a multilayer structure in this invention, the gas barrier layer which has gas barrier property can also be provided in the layer to comprise, for example. This gas barrier layer is made of ethylene vinyl alcohol copolymer resin, polymetaxylylene adipamide resin, polyvinylidene chloride resin, polyvinyl alcohol resin, etc., but the contents are oxidized because it does not allow oxygen or water vapor to permeate. Since it does not absorb moisture and does not allow the vapor of the contents to pass through, deterioration of flavor and the like can be prevented, and quality can be maintained over a long period of time.

Moreover, the shape of the part 2a of the cyclic | annular cutting part 2 which is the easy peeling part 6, and the part 8a of the cyclic | annular cutting part 8 which is the easy peeling part 7 can adjust the distance with the inner edge 41 of the heat seal part 4. For example, the projecting shape may be a semicircular shape as shown in FIG. 10A or a V-shaped protruding shape as shown in FIG.

Furthermore, although Example 1-3 demonstrated the example which made the shape of the opening part of the container main body 1 circular, what is necessary is just the container main body 1 which has the flange part 3 in the opening part periphery 31, and the shape of an opening part is an ellipse. It may be a shape or a polygon such as a rectangle.

Furthermore, as shown in FIG. 11, one or two or more auxiliary cut portions 21, 21,... (When provided in the flange portion 3) outside the part 2a of the annular cut portion 2 which is the easy peeling portion 6 are provided. Alternatively, one or two or more auxiliary cut portions 81, 81,... (When provided in the lid member 5) may be provided outside the part 8 a of the annular cut portion 8 that is the easy peeling portion 7. By providing the auxiliary cut portions 21 and 81, peeling starts from the auxiliary cut portions 21 or 81 close to the heat seal portion 4 even when the container body 1 and the lid member 5 are displaced and heat sealed. In addition, it is possible to reliably release the internal pressure increased by heating.

Furthermore, in the present invention, as described above, the internal pressure relief caused by the heating of the contents is always subjected to the easy peeling portion 6 which is a part 2a of the annular cut part 2 or a part of the annular cut part 8. In order to carry out through the easy peeling part 7 which is 8a, as shown in FIG. 12, the outer surface of the container main body 1 or the cover material 5 in the part 2a of the cyclic | annular cut | notch part 2 (in FIG. By providing an indication 9 on the outer surface) indicating that it is a steam outlet (for example, “steam outlet / high temperature precautions”), the cook avoids the easy peeling portions 6 and 7 and attaches the microwave packaging containers A and B to each other. It can be gripped and burns and the like can be prevented in advance.

It is a partially broken top view which shows 1st embodiment of this invention. It is an enlarged plan view of the flange part of the container main body of FIG. FIG. 3A is a vertical sectional view in the vicinity of the flange portion of FIG. 1, FIG. 3A is a sectional view cut along line AA in FIG. 2, and FIG. 3B is a sectional view cut along line BB in FIG. Is shown. 4A and 4B are vertical sectional views of the vicinity of the flange portion during heating in FIG. 1, FIG. 4A being a cross-sectional view cut along line AA in FIG. 2, and FIG. 4B being cut along line BB in FIG. FIG. FIG. 2 is a vertical sectional view in the vicinity of a flange portion at the time of opening in FIG. 1. It is a partially broken top view which shows the other example of 1st embodiment of this invention. It is a figure which shows 2nd embodiment of this invention, Fig.7 (a) is a vertical sectional view of the flange part vicinity, FIG.7 (b) is a partially broken top view. It is a vertical sectional view in the vicinity of the flange portion showing the third embodiment of the present invention. It is a top view by the side of the container main body of the lid | cover material of FIG. FIG. 10 is a view for explaining various shapes of a part of the annular cut portion of the present invention, and FIG. (B) is a part of the annular cut portion formed into a V shape. It is a figure of the structure which provided the auxiliary cut part in the outer side of a part of cyclic | annular cut part of this invention. It is the perspective view of the packaging container for microwave ovens of this invention, and is the figure which displayed the warning that it is a vapor | steam discharge port on the outer surface of an easily peelable part.

Explanation of symbols

A, B Packaging container for microwave oven 1 Container body 2 Annular cut 3 Flange 4 Heat seal 5 Lid 6 Easy peel 7 Easy peel 8 Annular cut 9 Display

Claims (5)

A container body that has a flange portion at the periphery of the opening, stores the contents, and is formed by laminating a plurality of layers, and closes the opening of the container body, and is heat-sealed at the flange portion. A packaging container for a microwave oven comprising:
A heat seal part heat sealed at the flange part,
An annular notch provided at the inner side of the container body from the inner edge of the heat seal portion at the flange portion;
An easily peelable portion provided in the annular cut portion , wherein the distance between the annular cut portion and the inner edge of the heat seal portion is smaller than the other portion of the annular cut portion in a part of the annular cut portion; Prepared,
The peeling force of the easy peeling part is smaller than the peeling force of the heat seal part so that the easy peeling part peels to form a vapor discharge port due to an increase in internal pressure of the microwave packaging container,
The easy peeling part peels off by heating in a microwave oven to form the vapor discharge port, and after forming the vapor discharge port, the heat seal part is left on the lid material side, and the lid material is A method for opening a packaging container for a microwave oven, wherein the container is peeled from the container body. A film-like lid formed by laminating a container body having a flange part at the periphery of the opening, and containing the contents, and a plurality of layers that close the opening part of the container body and are heat-sealed by the flange part A packaging container for a microwave oven comprising:
A heat seal part heat sealed at the flange part,
An annular notch provided on the inside of the lid from the inner edge of the heat seal part,
An easily peelable portion provided in the annular cut portion , wherein the distance between the annular cut portion and the inner edge of the heat seal portion is smaller than the other portion of the annular cut portion in a part of the annular cut portion; Prepared,
The peeling force of the easy peeling part is smaller than the peeling force of the heat seal part so that the easy peeling part peels to form a vapor discharge port due to an increase in internal pressure of the microwave packaging container,
The easy peeling part peels off by heating in a microwave oven to form the vapor outlet, and after forming the vapor outlet, the heat seal part is left on the container body side, A method for opening a packaging container for a microwave oven, wherein the container is peeled from the container body. The method for opening a packaging container for a microwave oven according to claim 1 or 2 , wherein a peeling force between the flange portion and the lid member in a part of the annular cut portion is 1 N / 15 mm to 18 N / 15 mm. . Claim 1, wherein the peel strength between the flange portion and the lid member in some cuts of the annular is not more than 60% of the peel strength between the flange portion and the lid member in the other portion of the cut portion of the annular- 4. A method for opening a microwave packaging container according to any one of 3 above. The microwave oven packaging according to any one of claims 1 to 4, wherein an indication of a steam outlet is provided on an outer surface of the container main body or the lid member in a part of the annular cut portion. How to open the container.

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