Package

Abstract

To provide a package whose opening part can be resealed even after the package is once opened, which can be heated in a microwave oven together with a container after the opening part is resealed.SOLUTION: A package 1 comprises a container main body 2 and a lid material 3 sealing an opening part of the container main body, which can be heated in a microwave oven. The lid material has a U-shaped notch 4 serving as a take-out port for contents, where the lid material is attached with an adhesive sheet member 6 for resealing which covers the whole of the U-shaped notch. One side of a straight portion of the notch in the U-shape formed in the lid material is shorter than the other side thereof, and a through-hole 7 is formed in the adhesive sheet member for resealing, at a portion corresponding to an extension line of the short straight portion 5.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention mainly relates to a package for storing food, which has a resealable opening and can be heated together with the container in a microwave oven after resealing.

Background Art

[0002] In packages for storing food, various packages that can be heated and cooked together with the container in a microwave oven after being taken out of the refrigerator have been proposed. The lid material described in Patent Document 1 is a sealed lid material having a function of automatically venting steam when heated together with the container in a microwave oven.

[0003] The lid material described in Patent Document 1 has a steam vent hole and a steam vent label for sealing it. The steam vent label has a non-sticking area covering the steam vent hole, a weak sticking area forming a steam passage reaching from the non-sticking area to the label end, and a strong sticking area adjacent to the outside of the non-sticking area and the weak sticking area. The non-sticking area is obtained by coating a non-sticking coat layer with a coating area ratio of 100% on a strong sticking layer coated on the entire surface of the steam vent label. The weak sticking area is a lid material characterized in that a non-sticking coat layer is coated with a coating area ratio of 10% or more and 90% or less on a strong sticking area coated on the entire surface.

[0004] The package for microwave treatment and the steam-permeable label described in Patent Document 2 are packages in which the airtightness of the container is ensured by the steam-permeable label before microwave treatment (microwave oven heating), and the steam in the container can be released before the internal pressure becomes very high during microwave treatment.

[0005] The package described in Patent Document 2 has a container for microwave treatment having a steam vent opening, and a steam-permeable label provided with a non-adhesive surface and an adhesive surface surrounding the non-adhesive surface on a label base material, and the steam-permeable label covers the steam vent opening at the non-adhesive surface and is attached to the container via the adhesive surface. In the package, the adhesive surface is composed of the back surface of an adhesive layer provided on the back surface side of the label base material, and a part or all of the adhesive layer contains thermally expandable fine particles. It is a package for microwave treatment characterized by this.

[0006] Both the lid material described in Patent Document 1 and the package described in Patent Document 2 relate to packages that can be heated in a microwave oven together with the container. However, on the other hand, in a packaging container for storing foods that are not used up at once, it is highly convenient if it can be re-sealed even after opening, but in the packages described in Patent Documents 1 and 2, no description regarding re-sealing is found.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] The problem to be solved by the present invention is to propose a package that can re-seal the opening even after being opened once, and after re-sealing, can be heated in a microwave oven together with the container.

Means for Solving the Problems

[0009] As a means for solving the above problems, the invention according to claim 1 is a package having a container body capable of microwave heating and a lid member for sealing the opening of the container body. The lid member has a U-shaped cut serving as an outlet for the contents, and a resealing adhesive sheet member covering the entire U-shaped cut is attached to the lid member. One side of the straight portion of the U-shaped cut provided in the lid member is shorter than the other side, and a through hole is formed in the resealing adhesive sheet member at a portion corresponding to the extension line of this short straight portion. By peeling off the resealing adhesive sheet member upward from the bottom of the U-shaped cut, the short straight portion of the U-shaped cut in the lid member is torn and reaches the through hole formed in the resealing adhesive sheet member. When the package is microwave-heated after resealing, the through hole acts as a steam vent hole. This is the characteristic of the package.

[0010] The package according to the present invention can be resealed after opening and can be heated in a microwave oven together with the container after resealing.

[0011] Further, the invention according to claim 2 is the package according to claim 1, characterized in that the distance from the end point of the short straight portion of the cut in the lid member to the through hole of the resealing adhesive sheet member is 5 mm or more and 50 mm or less.

[0012] Further, the invention according to claim 3 is the package according to claim 1 or 2, characterized in that the adhesive strength of the resealing adhesive sheet member is 5 N / 15 mm or more and 15 N / 15 mm or less in 180° peel at a peeling speed of 300 mm / min.

Advantages of the Invention

[0013] The package according to the present invention has a resealing adhesive sheet member capable of resealing the outlet, so it can be used for applications where the contents are not used up at once. Also, after resealing, even if the container is heated in a microwave oven, since a steam vent hole is formed, the container will not explode.

[0014] By appropriately controlling the distance (d) between the end point of the short linear portion of the cut provided in the lid material and the through hole provided in the resealing adhesive sheet member, as in the invention described in claim 2, a more stable steaming operation can be obtained.

[0015] By setting the adhesive force of the resealing adhesive sheet member within an appropriate range, as in the invention described in claim 3, smoother opening performance can be obtained.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0017] Hereinafter, with reference to the drawings, the package 1 according to the present invention will be described in detail. FIG. 1 is a perspective view showing an embodiment of the package 1 according to the present invention. FIG. 2 is a schematic plan view of the resealing adhesive sheet member 6. FIG. 3 is a plan explanatory view showing a state where the resealing adhesive sheet member 6 is attached to the lid material 3. FIG. 4 is a plan explanatory view showing a state where the resealing adhesive sheet member 6 is peeled off from the state of FIG. 3 and resealed. Hereinafter, the package 1 according to the present invention will be described with reference to these drawings.

[0018] The package 1 according to the present invention is a package having a container body 2 capable of being heated in a microwave oven and a lid member 3 capable of being heated in a microwave oven for sealing the opening of the container body 2. The lid member 3 has a U-shaped cut 4 serving as an outlet for the contents, and a resealing adhesive sheet member 6 covering the entire U-shaped cut 4 is attached to the lid member 3.

[0019] One side of the straight portion of the U-shaped cut 4 provided in the lid member 3 is shorter than the other, and a through hole 7 is formed in the resealing adhesive sheet member 6 at a portion corresponding to the extension line of the short straight portion 5.

[0020] By peeling the resealing adhesive sheet member 6 upward from the bottom of the U-shaped cut 4, the short straight portion 5 of the U-shaped cut 4 of the lid member 3 is torn and reaches the through hole 7 formed in the resealing adhesive sheet member 6. When the package 1 is heated in a microwave oven after resealing, the through hole 7 acts as a steam vent hole.

[0021] The U-shaped cut 4 provided in the lid member 3 may penetrate the lid member 3 or may be semi-penetrating. However, in the case of semi-penetrating, when the resealing adhesive sheet member 6 attached on the U-shaped cut 4 is peeled off, the lid member must be torn and the outlet must be opened.

[0022] Generally, the resealing adhesive sheet member 6 is provided with a knob portion 9 so that it can be easily held by hand when starting to peel. The knob portion 9 has no adhesiveness or has weak adhesiveness so that it is easy to provide a starting point for peeling. The knob portion 9 may be formed by forming a non-adhesive layer on the adhesive layer formed on the entire surface, or may be formed by not applying an adhesive to the base material from the beginning.

[0023] The shape of the through hole 7 is an ellipse with the longer side in the direction perpendicular to the peeling direction in Fig. 2, but there are no particular restrictions on the shape of the through hole 7. However, when peeling off the re-sealing adhesive sheet member 6, the crack in the lid member 3 does not necessarily exactly follow the extension of the short straight portion 5 of the U-shaped cut 4. Therefore, it is desirable that the width in the lateral direction is somewhat wide so that the crack does not deviate.

[0024] Fig. 3 is a plan explanatory view showing a state where the re-sealing adhesive sheet member 6 is attached to the lid member 3. The U-shaped cut 4 provided in the lid member 3 is completely covered by the re-sealing adhesive sheet member 6. Fig. 4 is a plan explanatory view showing a state where the re-sealing adhesive sheet member 6 is peeled off from the state of Fig. 3 and then re-sealed.

[0025] By peeling off the re-sealing adhesive sheet member 6, the lid member inside the U-shaped cut 4 is opened together with the re-sealing adhesive sheet member 6 to form an opening. By further peeling off the re-sealing adhesive sheet member 6, the short straight portion 5 of the U-shaped cut 4 in the lid member 3 generates a crack 10 from its end point 8, reaches the through hole 7, passes through the through hole 7, and reaches a height approximately the same as that of the longer straight portion of the U-shaped cut 4.

[0026] When heating the package 1 in a microwave oven in a re-sealed state, as shown in Fig. 5, the steam 11 ejected from the crack 10 of the lid member is ejected to the outside of the package through the through hole 7 of the re-sealing adhesive sheet member 6, so the container will not burst.

[0027] Fig. 6 is an explanatory view of the distance (d) from the end point 8 of the short straight portion 5 of the U-shaped cut 4 in the lid member 3 to the through hole 7 of the re-sealing adhesive sheet member 6. Since there will inevitably be some variation in the attachment position of the re-sealing adhesive sheet member 6 to the lid member 3, if the distance (d) is too short, there is a risk that the end point 8 of the short straight portion of the U-shaped cut 4 in the lid member 3 will be exposed from the through hole 7.

[0028] On the other hand, since the crack 10 in the lid material 3 does not necessarily proceed linearly from the short straight-line portion 5 of the U-shaped cut 4, if the distance (d) is too long, the crack 10 in the lid material may deviate from the through-hole 7.

[0029] Regarding the value of the distance (d), it has been found that a more stable steaming operation can be expected when it is 5 mm or more and 50 mm or less.

[0030] Regarding the adhesive force of the re-sealing adhesive sheet member 6, if the adhesive force is too strong, it will be difficult to peel off. On the other hand, if the adhesive force is too weak, there is a risk that the lid material cannot be opened or the crack cannot proceed on the extension line of the U-shaped cut 4.

[0031] Regarding the adhesive force of the re-sealing adhesive sheet member 6, it has been found that it is more desirable that it be 5 N / 15 mm or more and 15 N / 15 mm or less in a 180° peel at a peel rate of 300 mm / min.

[0032] Regarding the material, shape, molding method, etc. of the container body 2, there are no particular restrictions as long as it has a flange portion so that it can be hermetically sealed with the lid material 3. For example, it may be a tray-shaped formed by vacuum pressure forming a synthetic resin sheet, a cup-shaped formed by injection molding of synthetic resin, or a paper container formed into a tray shape or a cup shape. However, the flange surface needs to be made of a material capable of heat sealing so that the lid material 3 can be sealed.

[0033] Regarding the lid material 3, there are no particular restrictions on its layer structure as long as it has a sealant layer on the inner surface in order to heat-seal the flange portion of the container body 2. Various synthetic resin sheets and papers can be used in combination.

[0034] Regarding the layer structure of the re-sealing adhesive sheet member 6, a base material layer and an adhesive layer are essential, but there are no particular restrictions on the layer structure of the base material layer. Various synthetic resin sheets and papers can be used in combination.

[0035] A gas barrier layer can also be provided on the container body 2, the lid material 3, and the resealing adhesive sheet member 6. By providing the gas barrier layer, the storability of the contents is enhanced. However, due to the necessity of heating the entire container in a microwave oven, a metal foil such as aluminum foil cannot be used. Based on the following examples, the package according to the present invention will be described more specifically.

Example

[0036] As the container body, a container formed by vacuum pressure molding a three-layer sheet of polypropylene resin / ethylene vinyl alcohol copolymer resin / polypropylene resin having the shape shown in FIG. 1 was used. The container dimensions are an outer dimension of 130 mm × 250 mm × 50 mm, and the outer dimension of the bottom surface is 120 mm × 240 mm.

[0037] As the lid material, a laminate sheet of polyethylene terephthalate resin (thickness 12 μm) and unstretched polypropylene resin (thickness 50 μm) was used. The lid material was provided with a cut in a U shape with a short straight portion on one side as shown in FIG. 2. The width of the U shape is 80 mm.

[0038] As the resealing adhesive sheet member, an adhesive sheet having a layer structure of polyvinylidene chloride coated (K coat) stretched polypropylene resin film (thickness 20 μm) / adhesive / stretched polypropylene resin film (thickness 50 μm) / adhesive and having the shape shown in FIG. 2 was used. The dimensions are 105 mm × 200 mm. The dimensions of the elliptical through-hole are a major axis of 30 mm and a minor axis of 10 mm.

[0039] Samples of Examples 1 to 8 were each prepared by changing the distance (d) from the end point of the short straight portion of the cut in the lid material to the through-hole of the resealing adhesive sheet member from 2 mm to 60 mm. Each sample was filled with 50 g of curry, once opened and resealed, and then heated in a 600 W microwave oven to confirm the steam permeability. The results are summarized in Table 1.

[0040]

Table 1

[0041] From the results in Table 1, it can be seen that when the distance (d) is from 5 mm to 50 mm, more stable steam permeability can be expected.

Explanation of reference numerals

[0042] 1 ··· Package 2 ··· Container body 3 ··· Lid material 4 ··· U-shaped cut 5 ··· Short straight line portion 6 ··· Re-sealable adhesive sheet member 7 ··· Through hole 8 ··· End point of the short straight line portion 9 ··· Knob portion 10 ··· Crack of the lid material 11 ··· Water vapor d ··· Distance from the end point of the short straight line portion to the through hole

Claims

1. A package having a container body capable of being heated by a microwave oven and a lid member for sealing an opening of the container body, the lid member has a U-shaped cut serving as an outlet for the contents, and a resealing adhesive sheet member covering the entire U-shaped cut is attached to the lid member, one side of the straight portion of the U-shaped cut provided in the lid member is shorter than the other side, and a through hole is formed in the resealing adhesive sheet member at a portion corresponding to the extension line of this short straight portion, by peeling off the resealing adhesive sheet member upward from the bottom of the U-shaped cut, the short straight portion of the U-shaped cut in the lid member is torn and reaches the through hole formed in the resealing adhesive sheet member, a package characterized in that when the package is heated in a microwave oven after resealing, the through hole acts as a steam vent hole.

2. The package according to claim 1, characterized in that the distance (d) from the end point of the short straight portion of the cut in the lid member to the through hole of the resealing adhesive sheet member is 5 mm or more and 50 mm or less.

3. The package according to claim 1 or 2, characterized in that the adhesive strength of the resealing adhesive sheet member is 5 N / 15 mm or more and 15 N / 15 mm or less at a peeling speed of 300 mm / min and 180° peeling.

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