packaging container

Abstract

To propose a packaging container which has achieved both functions of steam cooking and browning cooking.SOLUTION: A packaging container which stores food and can be heated in a microwave oven in an unopened state, includes: an inner container on which food is placed; and an outer bag for storing the same. The inner container includes a heat generating body which generates heat by the irradiation of microwaves on a surface of a base material having heat resistance where the food comes into contact. The outer bag comprises a laminate in which a biaxially-oriented film which is the outermost layer, a polyolefin resin layer which is an intermediate layer, and thermoplastic nonwoven fabric which is the innermost layer and in which cellulose pulp is mixed are laminated. At an upper part of the packaging container, a steam discharge port is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] To provide a packaging container for storing food, which can brown food in addition to providing a steaming effect by generating steam when heated in a microwave oven in an unopened state. [Background technology]

[0002] Packaging bags equipped with a mechanism for releasing steam pressure (steam-passing mechanism) are known to prevent the packaging bag from bursting or the contents from scattering due to the pressure of steam generated when the packaging bag containing food is heated in a microwave oven. The packaging material and packaging product described in Patent Document 1 are packaging materials in which small holes generated by the pressure of steam expand and contract according to the amount of steam generated, thereby maintaining the internal pressure at or above normal pressure. This packaging material allows for continuous heating for a certain period of time, making steam cooking possible.

[0003] On the other hand, there is known a technique for browning food or making it crispy by heating it in a microwave oven. The container for microwave heating described in Patent Document 2 is a container that uses a heating element that generates heat when exposed to microwaves.

[0004] Some foods, such as frozen dumplings, require both steaming and browning, but simply combining the container and packaging bag described above is not feasible because the high heat generated by the heating element causes the outer packaging bag to melt and adhere to the container. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4817583 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-218769 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a packaging container that can perform both steam cooking and browning cooking functions. [Means for solving the problem]

[0007] As a means for solving the above-mentioned problems, the invention described in claim 1 is a packaging container that can store food and can be heated in a microwave oven when unopened, comprising an inner container on which the food is placed and an outer bag that stores the inner container, the inner container having a heat-resistant base material and a heating element that generates heat when irradiated with microwaves on the surface that comes into contact with the food, the outer bag being a laminate of a biaxially oriented film layer as the outermost layer, a polyolefin resin layer as the middle layer, and a thermoplastic resin nonwoven fabric mixed with cellulose pulp as the innermost layer, and a bag on the top of the packaging container. To release steam generated when heated in a microwave oven A packaging container characterized by having a water vapor release port.

[0008] The packaging container according to the present invention uses a thermoplastic resin nonwoven fabric containing highly heat-resistant cellulose pulp as the innermost layer of the outer bag, thereby preventing the outer bag from fusing due to heat.

[0009] The invention described in claim 2 is the packaging container described in claim 1, characterized in that the water vapor release port is a scratched opening that penetrates the outermost layer and the innermost layer of the laminate.

[0010] The invention described in claim 3 is the packaging container described in claim 1 or 2, characterized in that the thermoplastic resin constituting the thermoplastic resin nonwoven fabric is a polyolefin resin.

[0011] The invention described in claim 4 is the packaging container described in any one of claims 1 to 3, characterized in that the food to be stored is pan-fried dumplings. [Effects of the Invention]

[0012] The packaging container of the present invention comprises an inner container equipped with a heating element that generates heat when irradiated with microwaves, and an outer bag that houses the inner container. By arranging a thermoplastic resin nonwoven fabric mixed with highly heat-resistant cellulose pulp in the innermost layer of the outer bag, the inner surface of the outer bag does not melt and adhere to the inner container or food when heated in a microwave oven.

[0013] The outer bag is provided with a steam release port, so the outer bag will not burst when heated. Furthermore, if the steam release port is made by scratching the outermost and innermost layers of the laminate, the amount of steam released can be controlled as desired by changing the length of the scratch, making it easy to achieve optimal steam cooking.

[0014] The packaging container according to the present invention is ideally suited for storing foodstuffs that require both steaming and browning, such as pan-fried dumplings. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing one embodiment of a packaging container according to the present invention. [Figure 2] FIG. 2 is a perspective view showing a state in which the packaging container has been opened from the state shown in FIG. 1, the outer bag has been removed, and food has been placed in the inner container. [Figure 3] FIG. 3 is an explanatory cross-sectional view showing one embodiment of the laminate used in the outer bag of the packaging container according to the present invention. [Figure 4] FIG. 4 is an explanatory cross-sectional view showing one embodiment of the laminate used for the inner container of the packaging container according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The packaging container according to the present invention will be described in detail below with reference to the drawings. Fig. 1 is a perspective view showing one embodiment of a packaging container 1 according to the present invention. Fig. 2 is a perspective view showing a state in which the packaging container 1 has been opened from the state shown in Fig. 1, the outer bag 20 has been removed, and food 30 has been placed in the inner container 10. Fig. 3 is a cross-sectional explanatory view showing one embodiment of a laminate 21 used in the outer bag 20 of the packaging container 1 according to the present invention. Fig. 4 is a cross-sectional explanatory view showing one embodiment of a laminate used in the inner container 10 of the packaging container 1 according to the present invention.

[0017] The packaging container 1 according to the present invention is a packaging container that can store food and be heated in a microwave oven in an unopened state, and comprises an inner container 10 on which food 30 is placed, and an outer bag 20 that stores the inner container. The inner container 10 is provided with a heating element 12 that generates heat when irradiated with microwaves on the surface of a heat-resistant substrate 11 that comes into contact with the food 30, and the outer bag 20 is made of a laminate 21 that is made up of a biaxially oriented film layer 22 as the outermost layer, a polyolefin resin layer 23 as the middle layer, and a thermoplastic resin nonwoven fabric 24 mixed with cellulose pulp as the innermost layer. A steam release port 25 is provided at the top of the packaging container 1.

[0018] In the example shown in Figure 1, the outer bag 20 is a pillow packaging bag with a palm-sealed portion on the bottom surface, but there are no particular restrictions on the shape of the packaging bag, and it can be any shape such as a three-sided sealed bag, a four-sided sealed bag, or a gusseted pillow packaging bag.

[0019] 3 is a cross-sectional explanatory diagram showing an example of a laminate 21 constituting the outer bag 20. The laminate 21 is formed by laminating at least a biaxially oriented film layer 22 as the outermost layer, a polyolefin resin layer 23 as the middle layer, and a thermoplastic resin nonwoven fabric 24 containing cellulose pulp as the innermost layer. Although not shown in the figure, a printed layer is usually provided on the front or back surface of the biaxially oriented film layer 22. Furthermore, an adhesive layer is provided as needed to laminate the layers together.

[0020] The outermost biaxially oriented film layer 22 is usually printed, and therefore a biaxially oriented film with excellent printability is used. Examples of biaxially oriented films include common polyethylene terephthalate resin (PET) films and biaxially oriented polypropylene resin (OPP) films, and, when greater heat resistance is required, various heat-resistant films such as polybutylene terephthalate resin (PBT) films, polycarbonate resin films, polyvinylidene chloride resin films, cellulose triacetate resin films, and nylon films can be used.

[0021] The polyolefin resin layer 23 that serves as the intermediate layer may be an ethylene-based resin such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, or ethylene-methacrylic acid resin copolymer; or a blend resin of polyethylene and polybutene; or a polypropylene-based resin such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, or propylene-α-olefin copolymer.

[0022] The thermoplastic resin nonwoven fabric 24 that forms the innermost layer can be a nonwoven fabric made by mixing cellulose pulp with fibers obtained from the same material as that used for the polyolefin resin layer 23. Since cellulose pulp does not melt when heated, when this is used for the innermost layer of the outer bag 20, it is possible to prevent the innermost layer from melting and adhering to the inner container or food even when heated in a microwave oven.

[0023] However, when the laminate 21 is made into the outer bag 20, the innermost thermoplastic resin nonwoven fabric 24 must be heated together to function as a sealant, so the cellulose pulp mixing rate is preferably about 30% to 70%.

[0024] The water vapor release vent 25 can take various forms, such as sealing a through-hole previously provided in the laminate with a fragile seal, or providing a narrow fragile section in part of the sealed section of the packaging bag, and is not particularly limited. However, in the case of the outer bag of the present invention, since a three-layer laminate is used, the simplest and most stable method is to provide a scratching process 26 that penetrates through the outermost layer and the innermost layer.

[0025] The scratches can be made using a blade or a laser processing machine. By using this method, the size of the opening can be set to an appropriate size by adjusting the length of the scratches, so that an appropriate steaming time can be maintained.

[0026] 2 is a perspective view showing a state in which the packaging container 1 has been opened from the state shown in FIG. 1, the outer bag 20 has been removed, and food 30 has been placed in the inner container 10. The inner container 10 is made of a heat-resistant base material 11 such as cardboard, and a heating element 12 that generates heat when exposed to microwaves is partially provided on the base material 11. A tray-shaped container is used. A vapor-deposited film, called a susceptor, in which a metal such as aluminum is vapor-deposited on a heat-resistant base film such as a PET film can be used as the heating element 12. The heating element 12 is provided in the minimum area necessary to place the food on it.

[0027] As described above, the packaging container of the present invention can simultaneously perform both steaming and browning cooking, making it ideal for storing foods such as the pan-fried dumplings shown in Figure 2. [Explanation of symbols]

[0028] 1...Packaging container 10. Inner packaging 11...Base material 12 Heating element 20···Outer bag 21...Laminate 22. Biaxially oriented film layer 23 Polyolefin resin layer 24...Thermoplastic resin nonwoven fabric 25···Water vapor outlet 26···Wound Processing 30···Food

Claims

1. A packaging container that can store food and can be heated in a microwave oven when unopened, comprising an inner container for placing the food therein and an outer bag for storing the inner container, the inner container having a heat-resistant base material on the surface that comes into contact with the food, a heating element that generates heat when irradiated with microwaves, the outer bag being a laminate comprising a biaxially oriented film layer as the outermost layer, a polyolefin resin layer as the middle layer, and a thermoplastic resin nonwoven fabric mixed with cellulose pulp as the innermost layer, and a steam outlet at the top of the packaging container for releasing steam that is generated when the packaging container is heated in a microwave oven.

2. 2. The packaging container according to claim 1, wherein the water vapor release port is formed by scratching the outermost layer and the innermost layer of the laminate.

3. 3. The packaging container according to claim 1, wherein the thermoplastic resin constituting the thermoplastic resin nonwoven fabric is a polyolefin resin.

4. 4. The packaging container according to claim 1, wherein the food to be stored is pan-fried dumplings.

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