Packaging bag for microwave heating and packaged food for microwave heating

Abstract

To provide a packaging bag for microwave heating that can prevent hole opening when heated and has high laminate strength, and a packaged food product for microwave heating using the bag.SOLUTION: A laminated film 20 of the invention comprises: a base material layer 21 comprising a polyethylene terephthalate film having a barrier layer 21a of an oxide vapor deposited film; a first intermediate layer 24 comprising a polyethylene terephthalate film laminated on the inner surface side of the base material layer 21; a second intermediate layer 26 comprising a polyethylene terephthalate film laminated on the inner surface side of the first intermediate layer 24; and a heat-adhesive resin layer 28 comprising a polyolefin film laminated on the inner surface side of the second intermediate layer 26, wherein the first intermediate layer 24 or the second intermediate layer 26 has a linear tearing property at least at an opened portion.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a packaging bag for use in heating in a microwave oven and a packaged food product for use in heating in a microwave oven using the same. [Background technology]

[0002] A conventional packaged food for heating in a microwave oven is disclosed in Patent Document 1. In this packaged food for heating in a microwave oven, cooked food is filled and sealed in a packaging bag for heating in a microwave oven, and when eaten, the food is directly heated in a microwave oven while still sealed in the packaging bag for heating in a microwave oven.

[0003] The packaging bag for microwave heating is formed from a four-layer laminated film having, from the outer surface side, a base layer, a first intermediate layer, a second intermediate layer, and a heat-adhesive resin layer. The base layer is formed from a polyester film, and a printed layer is provided on the inner surface side. The first intermediate layer is formed from a polyester film, and a barrier layer such as an oxide vapor deposition film is provided on the outer surface side. The second intermediate layer is formed from a polyester film. The heat-adhesive resin layer is formed from a polyolefin film with heat sealability. Each of the four layers of film is dry laminated.

[0004] The packaging bag for microwave heating having the above-mentioned structure is filled with food and cooked in a microwave oven. During this process, the packaging bag for microwave heating can be prevented from being punctured by heating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-151945 A (pages 4 to 21, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned conventional packaging bags for microwave oven heating have a problem that the laminate strength is low and the bag is easily broken during transportation.

[0007] An object of the present invention is to provide a packaging bag for microwave heating which is capable of preventing holes from being formed during heating and has high lamination strength, and a packaged food for microwave heating using the same. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the packaging bag for microwave heating of the present invention is formed from a laminated film having a base layer made of a polyethylene terephthalate film having a barrier layer of an oxide vapor deposition film, a first intermediate layer made of a polyethylene terephthalate film laminated on the inner side of the base layer, a second intermediate layer made of a polyethylene terephthalate film laminated on the inner side of the first intermediate layer, and a heat-adhesive resin layer made of a polyolefin film laminated on the inner side of the second intermediate layer, and is characterized in that the first intermediate layer or the second intermediate layer has straight-line tearability at least at the opening location.

[0009] Furthermore, the present invention is characterized in that in the packaging bag for heating in a microwave oven having the above-mentioned configuration, the first intermediate layer or the second intermediate layer is made of a biaxially stretched film having linear tearability.

[0010] Furthermore, the present invention is characterized in that in the packaging bag for heating in a microwave oven having the above-mentioned configuration, the first intermediate layer or the second intermediate layer has a half-cut tear line.

[0011] The present invention also provides a packaging bag for microwave heating having the above-mentioned configuration, wherein the first intermediate layer or the The second intermediate layer is characterized by having a full cut tear line.

[0012] The present invention is also characterized in that in the packaging bag for microwave heating having the above-mentioned configuration, the base layer is disposed with the barrier layer on its inner surface side, and a printing layer is provided on the inner surface side of the barrier layer.

[0013] The packaged food for heating in a microwave oven of the present invention is characterized in that food is filled and sealed in a packaging bag for heating in a microwave oven having the above-mentioned configuration.

[0014] The present invention is also characterized in that in the packaged food for heating in a microwave oven having the above-mentioned configuration, the solid content of the food is 80 mass % or more. Effect of the Invention

[0015] According to the present invention, it is possible to prevent holes from being formed in the packaging bag for microwave heating during microwave heating and to improve the laminate strength of the packaging bag for microwave heating. In addition, since the first intermediate layer or the second intermediate layer has linear tearability at the opening location, the packaged food for microwave heating can be easily opened. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a front view showing a packaged food for microwave heating according to a first embodiment of the present invention; [Diagram 2] FIG. 1 is a perspective view showing a packaging bag for a packaged food for heating in a microwave oven according to a first embodiment of the present invention; [Diagram 3] FIG. 1 is a cross-sectional view showing a laminate film forming a packaging bag for a packaged food to be heated in a microwave oven according to a first embodiment of the present invention. [Figure 4] FIG. 5 is a front view showing a packaged food for microwave heating according to a second embodiment of the present invention. [Diagram 5] FIG. 2 is a cross-sectional view showing a laminate film forming a packaging bag for a packaged food to be heated in a microwave oven according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view showing a laminated film forming a packaging bag for a packaged food to be heated in a microwave oven according to a modified example of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] First Embodiment Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows a front view of a packaged food for heating in a microwave oven according to a first embodiment. Packaged food for heating in a microwave oven 10 is produced by filling cooked food W into storage section 2 of a packaging bag 1 for heating in a microwave oven (hereinafter referred to as "packaging bag 1") and sealing it.

[0018] The packaging bag 1 is a four-sided sealed bag in which the periphery of two laminated films 20 is thermally sealed with a seal portion 3. The packaging bag 1 may be a three-sided sealed bag, a pouch with a gusset, a standing pouch, a pillow-shaped bag, etc. The packaging bag 1 may also be provided with a steaming portion that allows steam to pass through when heated in a microwave oven.

[0019] An opening initiation portion 4 consisting of a V-notch is provided on the sealed portion 3 at both the left and right ends of the upper portion of the packaging bag 1. The packaging bag 1 is opened by tearing from the opening initiation portion 4. The opening initiation portion 4 may be formed by an I-notch or U-notch, or may be formed by a group of scars consisting of multiple scars.

[0020] Fig. 2 shows a perspective view of the packaging bag 1 before it is filled with food W. After the packaging bag 1 has an opening 1a at the upper end and is filled with food W, the opening 1a is sealed with a seal part 3 to form a packaged food product 10 for heating in a microwave oven (see Fig. 1).

[0021] 3 shows a cross-sectional view of the laminated film 20. The laminated film 20 has a four-layer structure including a base layer 21, a first intermediate layer 24, a second intermediate layer 26, and a thermal adhesive resin layer 28 in this order from the outer surface side.

[0022] The substrate layer 21 is a base film made of a polyethylene terephthalate film, on the inner surface of which a barrier layer 21a and a printed layer 22 are formed. Specifically, a biaxially oriented polyethylene terephthalate film is used as the base film. The thickness of the substrate layer 21 is, for example, 5 to 50 μm.

[0023] Barrier layer 21a is formed by depositing an oxide vapor deposition film of aluminum oxide, silicon oxide, or the like on a base film. This provides packaging bag 1 with gas barrier properties. Barrier layer 21a has a thickness of, for example, 0.1 nm to 1 μm. Because barrier layer 21a is formed from an oxide vapor deposition film, packaged food 10 for microwave heating can be heated in a microwave oven.

[0024] The printed layer 22 is disposed on the inner surface side of the barrier layer 21a and forms a pattern or the like. That is, the printed layer 22 is printed on the barrier layer 21a. The printed layer 22 can be printed by gravure printing, offset printing, letterpress printing, screen printing, or the like. The thickness of the printed layer 22 is, for example, 2 to 5 μm.

[0025] The first intermediate layer 24 is laminated on the inner surface side of the base layer 21, and is formed of a polyethylene terephthalate film. Specifically, a biaxially oriented polyethylene terephthalate film having linear tearability is used as the first intermediate layer 24. As a result, the first intermediate layer 24 has linear tearability. The thickness of the first intermediate layer 24 is, for example, 5 to 50 μm.

[0026] The second intermediate layer 26 is laminated on the inner surface side of the first intermediate layer 24, and is formed of a polyethylene terephthalate film. Specifically, a biaxially oriented polyethylene terephthalate film is used as the second intermediate layer 26. The thickness of the second intermediate layer 26 is, for example, 5 to 50 μm.

[0027] The thermal adhesive resin layer 28 is laminated on the inner surface side of the second intermediate layer 26, and is formed of a polyolefin film that can be melted and welded by heat. As the polyolefin film that forms the thermal adhesive resin layer 28, a non-oriented polypropylene film (CPP), a linear low density polyethylene film (LLDPE), a low density polyethylene film (LDPE), a high density polyethylene film (HDPE), etc. can be used. The opposing thermal adhesive resin layers 28 are thermally bonded to form the seal portion 3 (see FIG. 1). The thickness of the thermal adhesive resin layer 28 is, for example, about 20 to 80 μm.

[0028] The base material layer 21 on which the printing layer 22 is printed and the first intermediate layer 24 are dry laminated with an adhesive layer 23 made of an adhesive. The first intermediate layer 24 and the second intermediate layer 26 are dry laminated with an adhesive layer 25 made of an adhesive. The second intermediate layer 26 and the thermal adhesive resin layer 28 are dry laminated with an adhesive layer 27 made of an adhesive.

[0029] In packaged food 10 for heating in a microwave oven having the above configuration, when food W is to be eaten, packaging bag 1 is heated in a microwave oven while being sealed. The upper end of packaging bag 1 is then torn open from opening start part 4, and food W is removed. If the four layers of film in packaging bag 1 had different orientations, opening would be difficult, but since first intermediate layer 24 made of a biaxially oriented film has linear tearability, packaged food 10 for heating in a microwave oven can be opened easily.

[0030] There is no particular limitation on the food W to be packed in the packaging bag 1. By forming the packaging bag 1 with the laminated film 20 having the above-mentioned configuration, it is possible to prevent the packaging bag 1 from being punctured by heating in a microwave oven. In addition, it is possible to prevent the packaging bag 1 from being punctured even when heated in a 1000 to 1900 W commercial microwave oven.

[0031] In particular, in food W with a high solid content, the solid content that becomes hot is likely to come into contact with the inner surface of the packaging bag 1. In addition, in food W that contains solid content and high-viscosity liquid content, the solid content that becomes hot and has a relatively small particle size (for example, 1 to 5 mm) is likely to be sandwiched in the narrow space near the seal portion 3 and come into contact with the inner surface of the packaging bag 1. In addition, in food W with a high viscosity liquid content and high Brix degree, the inner surface of the packaging bag 1 is likely to become hot due to the viscosity and sugar content. Examples of such food W include sauces such as meat sauce, white sauce, and carbonara sauce, rice bowl bases for beef bowls, oyakodon, and Chinese rice bowls, and cooked foods such as curry, stew, mapo tofu, sweet and sour pork, and taco rice meat.

[0032] The packaging bag 1 configured as above can prevent holes from being formed in the packaging bag 1 when heated in a microwave oven for food W with a solid content of 80% by mass or more. Furthermore, the packaging bag 1 configured as above can prevent holes from being formed in the packaging bag 1 when heated in a microwave oven for food W with a liquid content of 3000 to 20000 mPa s and a solid content of 1% by mass or more. Furthermore, the packaging bag 1 configured as above can prevent holes from being formed in the packaging bag 1 when heated in a microwave oven for food W with a liquid content of 3000 to 20000 mPa s and a Brix degree of the liquid content of 10 to 35%.

[0033] The Brix degree is the number of grams of sucrose in 100 g of sucrose solution at 20° C. In this application, the measured value including various sugars, organic acids, etc. measured by a refractometer is converted into sucrose and used as the Brix degree.

[0034] Furthermore, the laminated film 20 having the above-mentioned configuration can increase the laminate strength of the packaging bag 1, and can prevent the packaging bag 1 from breaking during transportation or the like due to delamination.

[0035] According to this embodiment, the laminated film 20 has a base layer 21 made of a polyethylene terephthalate film having a barrier layer 21a, a first intermediate layer 24 made of a polyethylene terephthalate film, a second intermediate layer 26 made of a polyethylene terephthalate film, and a heat-adhesive resin layer 28 made of a polyolefin film. This makes it possible to prevent holes from being formed in the packaging bag 1 (packaging bag for microwave heating) during microwave heating. In addition, the laminate strength of the packaging bag 1 can be improved, and tearing of the packaging bag 1 during transportation, etc. Furthermore, since the first intermediate layer 24 has linear tearability, the packaged food 10 for microwave heating can be easily opened.

[0036] Moreover, since first intermediate layer 24 is made of a biaxially stretched film having straight-line tearability, first intermediate layer 24 having straight-line tearability can be easily realized. If second intermediate layer 26 is formed from a biaxially stretched film having straight-line tearability, packaged food 10 for heating in a microwave oven can be easily opened. Therefore, it is sufficient that first intermediate layer 24 or second intermediate layer 26 has straight-line tearability.

[0037] In addition, the barrier layer 21a is disposed on the inner surface side of the base material layer 21, and the printed layer 22 is provided on the inner surface side of the barrier layer 21a. Therefore, the barrier layer 21a made of a vapor deposition film having low adhesive strength with an adhesive is not in direct contact with the adhesive layer 23, so that the laminate strength of the packaging bag 1 can be easily increased.

[0038] Furthermore, even in the case of food W having a solid content of 80% by mass or more, it is possible to prevent holes from being formed in the packaging bag 1 due to heating in a microwave oven.

[0039] Furthermore, even in the case of food W having a liquid content of 3000 to 20000 mPa·s and a solid content of 1 mass % or more, it is possible to prevent holes from being formed in the packaging bag 1 due to heating in a microwave oven.

[0040] Furthermore, even in the case of food W having a liquid content with a viscosity of 3000 to 20000 mPa·s and a Brix degree of the liquid content of 10 to 35%, it is possible to prevent holes from being formed in the packaging bag 1 due to heating in a microwave oven.

[0041] <Second embodiment> Next, Fig. 4 shows a front view of a packaged food 10 for heating in a microwave oven according to a second embodiment, and Fig. 5 shows a cross-sectional view of a main part of a laminated film 20 forming a packaging bag 1. In this embodiment, a tear line 5 is provided on the upper part of the packaging bag 1. The other parts are the same as those of the first embodiment.

[0042] The tear line 5 is formed on the second intermediate layer 26 by laser processing or half-cutting with a cutting blade, and connects the left and right tear start portions 4. This gives the packaging bag 1 linear tearability in the left-right direction at the tearing location. Therefore, the packaged food 10 to be heated in a microwave oven can be easily opened along the tear line 5.

[0043] According to this embodiment, it is possible to obtain the same effects as in the first embodiment. In addition, since the half-cut opening line 5 is provided in the second intermediate layer 26, the packaged food 10 for heating in a microwave oven can be easily opened. The half-cut opening line 5 may be provided in the first intermediate layer 24 instead of the second intermediate layer 26.

[0044] 6, the opening line 5 may be formed by cutting the entire first intermediate layer 24 or the second intermediate layer 26 with a cutting blade. This allows the opening portion of the packaging bag 1 to be given linear tearability in the left-right direction. EXAMPLES

[0045] Next, examples and comparative examples of packaged food 10 for microwave heating will be described, but the present invention is not limited to the following examples. As shown below, for each example and comparative example, the occurrence of holes in packaging bag 1 and the laminate strength of packaging bag 1 during microwave heating were examined.

[0046] In each of the Examples and Comparative Examples, the viscosity of the liquid content of Food W was measured at 50° C. using a B-type rotational viscometer. As described above, the Brix degree of the liquid content of Food W was calculated by converting the measured value, including various sugars, organic acids, and other components, measured at 20° C. using a refractometer into sucrose, to obtain the Brix degree.

[0047] Examples 1 to 7 use packaging bags 1 having the same configuration as the first embodiment. The base layer 21 is a 12 μm-thick biaxially oriented polyethylene terephthalate film on which a barrier layer 21a of an aluminum oxide vapor deposition film and a printed layer 22 are provided. The first intermediate layer 24 uses a 12 μm-thick biaxially oriented polyethylene terephthalate film. The second intermediate layer 26 uses a 12 μm-thick biaxially oriented polyethylene terephthalate film. The thermal adhesive resin layer 28 uses a 60 μm-thick unoriented polypropylene film.

[0048] The food W of Example 1 is taco rice meat having a solid content of 100% by mass (liquid content of 0% by mass). EXAMPLES

[0049] Food W in Example 2 is sweet and sour pork with a solid content of 90% by mass and a liquid content of 10% by mass. The liquid content of Food W has a viscosity of 3000 mPa·s and a Brix degree of 10%. EXAMPLES

[0050] Food W in Example 3 is sweet and sour pork with a solid content of 80% by mass and a liquid content of 20% by mass. The liquid content of Food W has a viscosity of 3000 mPa·s and a Brix degree of 10%. EXAMPLES

[0051] Food W in Example 4 is a tomato sauce having a solid content of 1 mass % and a liquid content of 99 mass %. The liquid content of Food W has a viscosity of 3650 mPa·s and a Brix degree of 15%. EXAMPLES

[0052] Food W in Example 5 is a tomato sauce having a solid content of 1 mass % and a liquid content of 99 mass %. The liquid content of Food W has a viscosity of 15000 mPa·s and a Brix degree of 18%. EXAMPLES

[0053] Food W in Example 6 is a pasta sauce having a solid content of 22% by mass and a liquid content of 78% by mass. The liquid content of Food W has a viscosity of 5000 mPa·s and a Brix degree of 14%. EXAMPLES

[0054] Food W of Example 7 is a pasta sauce having a solid content of 22% by mass and a liquid content of 78% by mass. The liquid content of Food W has a viscosity of 20000 mPa·s and a Brix degree of 25%. EXAMPLES

[0055] Food W in Example 8 is a pasta sauce having a solid content of 20% by mass and a liquid content of 80% by mass. The liquid content of Food W has a viscosity of 16000 mPa·s and a Brix degree of 10%.

[0056] [Comparative Example 1] In the packaging bag 1 of the packaged food 10 for microwave heating in Comparative Example 1, a barrier layer is provided on the first intermediate layer 24. That is, the base layer 21 has a printed layer 22 provided on a biaxially oriented polyethylene terephthalate film having a thickness of 12 μm. The first intermediate layer 24 has a barrier layer of an aluminum oxide vapor deposition film provided on the outer surface of a biaxially oriented polyethylene terephthalate film having a thickness of 12 μm. The second intermediate layer 26 uses a biaxially oriented polyethylene terephthalate film having a thickness of 12 μm. The thermal adhesive resin layer 28 uses a non-oriented polypropylene film having a thickness of 60 μm. The food W in Comparative Example 1 is the same taco rice meat as in Example 1.

[0057] [Comparative Example 2] The packaging bag 1 of the packaged food 10 for heating in a microwave oven in Comparative Example 2 is the same as that in Comparative Example 1. The food W in Comparative Example 2 is the same sweet and sour pork as in Example 3.

[0058] [Comparative Example 3] The packaging bag 1 of the packaged food 10 for microwave heating in Comparative Example 3 is formed in a three-layer structure omitting the second intermediate layer 26, and the other parts are the same as those in Example 1. The food W in Comparative Example 3 is the same taco rice meat as in Example 1.

[0059] [Comparative Example 4] The packaging bag 1 of the packaged food 10 for heating in a microwave oven in Comparative Example 4 is the same as that in Comparative Example 3. The food W in Comparative Example 4 is the same sweet and sour pork as in Example 3.

[0060] [Table 1]

[0061] Table 1 shows the results of investigating holes in the packaging bag 1 and the laminate strength of the packaging bag 1 when the packaged food 10 for heating in a microwave oven of each Example and Comparative Example was heated in a 1900 W microwave oven. In Table 1, cases in which no holes in the packaging bag 1 occurred are indicated with "◯", and cases in which holes occurred are indicated with "X". Furthermore, for the laminate strength, "◯" indicates 2N / 15mm or more, and "X" indicates less than 2N / 15mm.

[0062] According to Examples 1 to 3, when the solid content of the food W is 80 mass % or more, holes are generated. No hole formation occurred in the packaging bags 1 of Examples 1 to 8, but holes occurred in the packaging bags 1 of Comparative Examples 3 and 4, which were filled with the same food W. According to Examples 2 to 8, in the case of food W containing a solid component and a high-viscosity liquid component, no hole formation occurred in the food W containing a high-viscosity liquid component with a high Brix degree. Furthermore, while the packaging bags 1 of Examples 1 to 8 had high laminate strength, the packaging bags 1 of Comparative Examples 1 and 2 had low laminate strength. [Industrial Applicability]

[0063] The present invention can be used in packaged foods for heating in a microwave oven. [Explanation of symbols]

[0064] 1. Packaging bag (packaging bag for microwave heating) 2 Storage area 3. Seal Part 4 Opening start part 5 Opening Line 10. Packaged foods for microwave heating 20 Laminated Film 21 Base material layer 21a Barrier layer 22 Printing layer 23, 25, 27 Adhesive layer 24 First Middle Class 26 The second middle class 28 Heat adhesive resin layer W Food

Claims

[Claim 1] A packaging bag for heating in a microwave oven is formed from a laminated film having a base layer made of a polyethylene terephthalate film having a barrier layer of an oxide vapor deposition film, a first intermediate layer made of a polyethylene terephthalate film laminated on the inner side of the base layer, a second intermediate layer made of a polyethylene terephthalate film laminated on the inner side of the first intermediate layer, and a heat-adhesive resin layer made of a polyolefin film laminated on the inner side of the second intermediate layer, wherein the first intermediate layer or the second intermediate layer has linear tearability at least at the opening location.

Images