Packaging

Abstract

To propose a package which has high resistance to vibration and shock, is less likely to cause accident in a distribution process, and has a steam permeable mechanism for automatically passing steam by heating by a microwave oven.SOLUTION: In a package 1 obtained by heat-sealing a lid material 4 having a sealant layer 7 to a flange part of a container body 2 having a flange part 3, when a portion of the flange part where a seal is peeled off due to steam generated when the container body sealed with the lid material filled with water is heated by a microwave oven is defined as a preferential steam permeable region 8, the preferential steam permeable region of the flange part is partially subjected to cutting processing, a cutting processing part 9 is not formed to communicate from the inside to the outside of the flange part, and does not have a depth that penetrates a thickness of the flange part, and a ratio of an area of the portion subjected to the cutting processing to an area of the preferential steam permeable region is 5% or more and 90% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a package, and more particularly to a package having a steam passage mechanism that automatically releases generated steam when the package is heated in a microwave oven while still sealed. [Background technology]

[0002] In recent years, as cooking methods using microwave ovens have become more common, attention has been focused on packaging containers that can be heated in their containers in order to avoid the hassle of first removing the contents from the container and then transferring them to another heat-resistant container or the like before heating them.

[0003] In order to prevent the container from exploding due to steam generated during heating, some containers are instructed to be opened by removing a portion of the seal before heating. However, the reality is that such instructions are not followed, and there are a constant stream of accidents in which explosions and scattering occur in microwave ovens.

[0004] In view of this, a package has been proposed that is equipped with a so-called steam passage mechanism, which allows the generated water vapor to automatically escape even when the package is heated without being opened in advance. The packaging material described in Patent Document 1 is a packaging material in which cutting lines are engraved on a stretched synthetic resin film, and an unstretched film is attached to the cutting lines via a low-melting point heat seal agent.

[0005] When a package made from the packaging material described in Patent Document 1 is heated in a microwave oven while unopened, the unstretched film at the cutting line engraved in the stretched film is broken by the heat and opens up, allowing the generated water vapor to escape, thereby preventing accidents such as explosions.

[0006] In a package using the packaging material described in Patent Document 1, the strength of the packaging material is inevitably weakened by the cutting line engraved in the stretched film that provides the strength of the packaging material. For this reason, not only is there a risk of the cutting line tearing and causing pinholes if the package is accidentally dropped, but there is also a risk of such accidents occurring due to vibrations or handling during distribution. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 4817583 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved by the present invention is to provide a package that is highly resistant to vibration and impact, is less likely to cause accidents during distribution, and is equipped with a steam-passing mechanism that automatically passes steam when heated in a microwave oven. [Means for solving the problem]

[0009] As a means for solving the above-mentioned problems, the invention described in claim 1 is a package formed by heat-sealing a lid material having a sealant layer to the flange of a container body having a flange, and when the container body sealed with the lid material and filled with water is heated in a microwave oven, the part of the flange where the seal peels off due to the generated steam is defined as a preferential steam passage region. The preferential steam passage region of the flange is partially machined, and the machined part is not formed so as to communicate from the inside to the outside of the flange, and does not penetrate the thickness of the flange. This packaging body is characterized in that the ratio of the area of ​​the cut portion to the area of ​​the preferential vapor passage region, rather than the depth of passage, is 5% or more and 90% or less.

[0010] The packaging body of the present invention has been subjected to cutting processing in the priority steam passage area, which is a part that is inherently easy for steam to pass through due to the shape of the container body, so that it can stably exhibit the function of automatically passing steam when heated in a microwave oven.

[0011] The invention described in claim 2 is the packaging body described in claim 1, characterized in that the lid material has a synthetic resin stretched film base material and an easily peelable sealant layer.

[0012] The invention described in claim 3 is the packaging body described in claim 2, characterized in that the lid material has a gas barrier layer.

[0013] The invention described in claim 4 is a packaging body described in any one of claims 1 to 4, characterized in that the container body is rectangular in shape, priority vapor passage areas are present at four corners, and cutting is performed on at least one of these areas.

[0014] The invention described in claim 5 is a packaging body described in any one of claims 1 to 4, characterized in that the shape of the container body is an oval shape having two opposing straight sides, the preferential vapor passage areas are present in a total of four locations at both ends of the two straight sides, and at least one of these locations has been subjected to cutting processing. Effect of the Invention

[0015] The packaging body of the present invention has been subjected to cutting processing in the priority steam passage area, which is a part that is inherently easy for steam to pass through due to the shape of the container body, so that it can stably exhibit the function of automatically passing steam when heated in a microwave oven.

[0016] Furthermore, since the machined portion is provided without penetrating the flange portion either horizontally or vertically, the necessary resistance to shocks when dropped and vibrations during transportation is maintained.

[0017] By specifying the area of ​​the machined portion to be 5% to 90% of the area of ​​the preferential vapor passage region, both vapor passage stability and resistance to dropping and vibration are stably achieved.

[0018] When the covering material has a synthetic resin stretched film base material and an easily peelable sealant layer, as in the invention described in claim 2, it can more stably exhibit stable vapor permeability and resistance to dropping and vibration.

[0019] When the lid material has a gas barrier layer as in the invention described in claim 3, it is possible to impart long-term storage stability to the package.

[0020] When the container body is rectangular or oval in shape, as in the invention described in claim 4 or 5, the preferential vapor passage areas are present at the four corners, and by performing cutting processing on these parts, the features of the present invention can be maximized. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an explanatory plan view showing one embodiment of a package according to the present invention, in which the container body has a rectangular shape. [Diagram 2] FIG. 2 is a cross-sectional explanatory view showing the structure of the AA′ cross section of FIG. [Diagram 3] FIG. 3 is an explanatory plan view showing another embodiment of the package according to the present invention, in which the container body has a rectangular shape and the machined portion has a circular shape. [Figure 4] FIG. 4 is a cross-sectional explanatory view showing the structure of the cross section taken along line BB' of FIG. [Diagram 5] FIG. 5 is an explanatory plan view showing another embodiment of the package according to the present invention, in which the container body has an oval shape and the machined portion has a shape similar to a trapezoid. [Figure 6] FIG. 6 is an explanatory cross-sectional view showing another embodiment of the lid material used for the package according to the present invention. [Figure 7] FIG. 7 is a schematic plan view showing the shape of the container body of the package of the embodiment. [Figure 8] FIG. 8 is a schematic cross-sectional view of a package in which contents are placed in the container body of FIG. 7 and the lid is sealed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The package according to the present invention will be described in detail below with reference to the drawings. Fig. 1 is an explanatory plan view showing one embodiment of the package 1 according to the present invention, in which the shape of the container body 2 is rectangular. Fig. 2 is an explanatory cross-sectional view showing the structure of the AA' cross section in Fig. 1. Fig. 3 is an explanatory plan view showing another embodiment of the package according to the present invention, in which the shape of the container body is rectangular and the shape of the machined portion is circular. Fig. 4 is an explanatory cross-sectional view showing the structure of the BB' cross section in Fig. 3.

[0023] The package 1 according to the present invention is a package obtained by heat-sealing a lid material 4 having at least a sealant layer 7 to a flange portion of a container body 2 having a flange portion 3. For convenience of explanation, the lid material 4 is omitted in Fig. 1 as it is transparent.

[0024] Here, if we define the flange portion where the seal ultimately peels off due to the steam generated when a package made by filling an empty container body with water and sealing it with a lid is heated in a microwave oven as the preferential steam passage region, then when the container body is rectangular or square in shape, as shown in Figure 1, the preferential steam passage region appears at the four corners of the container body in the shape shown in the figure.

[0025] 5 is a plan view of another embodiment of the package 1 according to the present invention, in which the container body 2 has an oval shape with two opposing straight sides. In the case of such a shape, the preferential vapor passage regions appear in a Mount Fuji shape at four locations, at both ends of the two straight sides, as shown in the figure. These areas can also be expressed as being in the vicinity of the location where the curvature changes.

[0026] Although not specifically shown, when the shape of the container body is circular, the entire flange portion becomes the preferential vapor passage region.

[0027] The packaging body 1 according to the present invention is characterized in that cutting is applied partially within the preferential steam passage region 8 of the flange portion 3. The cut portion 9 is not formed so as to communicate from the inside to the outside of the flange portion 3, and does not extend deep enough to penetrate the thickness of the flange portion 3. Furthermore, the packaging body 1 according to the present invention is characterized in that the ratio of the area of ​​the cut portion to the area of ​​the preferential steam passage region 8 is 5% or more and 90% or less.

[0028] The shape of the cut-out portion 9 may be a plurality of straight lines as shown in FIG. 1, or may be a circle as shown in FIG. 3. In the example of FIG. 5, it is provided at the top of the Fuji-shaped preferential vapor passage area. Thus, there is no particular restriction on the shape of the cut-out portion 9, but it may be, for example, a straight line. In the case of FIG. 1, when comparing a case where the nozzles are formed radially toward the outside of the vessel body with a case where the same number of nozzles are formed perpendicularly to the radial shape, it has been confirmed that steam passes more smoothly when the nozzles are formed radially.

[0029] In either case of the examples shown in the figures, the machined portion 9 is not formed to communicate from the inside to the outside of the flange portion 3, and is not deep enough to penetrate the thickness of the flange portion 3. Furthermore, the ratio of the area of ​​the machined portion to the area of ​​the preferential vapor passage region 8 is 5% or more and 90% or less.

[0030] If the machined portion 9 is provided so as to communicate between the inside and outside of the flange portion 3, or if it is deep enough to penetrate the flange portion 3, this may cause poor sealing. It has been experimentally confirmed that if the ratio of the area of ​​the machined portion to the area of ​​the priority vapor passage region 8 is less than 5%, the effect of the machined portion in promoting vapor passage is weakened. It has also been found that if this ratio exceeds 90%, the resistance to vibrations and shocks during transportation is insufficient.

[0031] The machined portion 9 may be formed as a post-processing step after molding the container body 2, or may be formed simultaneously with molding. The method for forming the machined portion 9 may literally be a cutting process using a blade, or may be a method of pressing a heated jig like stamping. When there are multiple preferential vapor passage regions 8, the machined portion 9 is provided in at least one of them.

[0032] There are no particular restrictions on the material of the container body 2, but in consideration of heat resistance to microwave heating, moldability, cost, etc., heat-resistant general-purpose resins such as polypropylene resin, polyethylene terephthalate resin, polyamide resin, etc. As a multi-layer sheet, a resin layer with gas barrier properties may be provided on the inside.

[0033] The method for forming the container body 2 is not particularly limited, although vacuum forming and vacuum / compressed air forming are the most common. Press molding using male and female molds and injection molding are also possible.

[0034] The sealant layer 7 is essential for the lid material 4 since it is necessary to heat seal the container body 2 to seal it. Polyolefin resins are generally used as the material for the sealant layer 7, and specifically, ethylene resins 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, and ethylene-methacrylic acid resin copolymer, blend resins of polyethylene and polybutene, and polypropylene resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer are used. Commercially available easy-peel sealant films are also preferably used.

[0035] The base material for holding the sealant layer 7 may be polypropylene resin, polyethylene terephthalate resin, polyamide resin, paper, or the like.

[0036] Since the base material for the lid material is often subjected to printing processing, various synthetic resin oriented films with excellent printability are preferably used, such as oriented polypropylene resin film (OPP), oriented polyethylene terephthalate resin film (PET), and oriented polyamide film (O nylon).

[0037] A plurality of sheets are often laminated together to form the lid material 4. For the lamination, dry lamination using an adhesive, rudder lamination using a melt extruded resin, or the like is used.

[0038] When gas barrier properties are required for the lid material 4, a layer having gas barrier properties can be provided. Fig. 6 is a cross-sectional explanatory diagram showing another embodiment of the lid material 4 used in the package 1 according to the present invention. In this example, a synthetic resin stretched film substrate 5, a gas barrier layer 6, and a sealant layer 7 are bonded together. Note that the adhesive layer is omitted in the figure.

[0039] The gas barrier layer 6 may be a gas barrier film such as a polyvinylidene chloride film, a polyvinyl alcohol film, an ethylene-vinyl alcohol copolymer film, a gas barrier nylon film, or a gas barrier polyethylene terephthalate (PET) film; a metal vapor deposition film in which a metal such as aluminum is vapor-deposited on a PET film; an inorganic oxide vapor deposition film in which an inorganic oxide such as aluminum oxide or silicon oxide is vapor-deposited on a PET film; or a gas barrier coating layer such as a polyvinylidene chloride coating, a coating containing a water-soluble resin and an inorganic layered compound, or a coating in which a metal alkoxide or its hydrolysate is reacted with an isocyanate compound.

[0040] Metal foils such as aluminum foils that are generally used as gas barrier layers cannot be used in packages that are intended to be heated in a microwave oven, such as the package of the present invention. The package of the present invention will be described in more detail below based on examples and comparative examples.

[0041] <Example 1> The container body was made by forming a 600 μm thick polypropylene resin sheet containing filler into a square container by vacuum and pressure forming, as shown in Figures 7 and 8. The length and width are 185 mm, the depth is 50 mm, and the flange width is 6.5 mm.

[0042] When this container body was filled with water, sealed with a lid, and heated in a microwave oven, it was found that it had four corners with preferential vapor passage regions of the shape shown in Figure 1. Therefore, one of these corners was machined in a linear manner as shown in Figure 1 to form a machined part. The ratio of the area of ​​the machined part to the area of ​​the preferential vapor passage region (one place) (machined area ratio) was set to 5%.

[0043] The lid material used was a three-layer lid material shown below. <Covering material composition>: PET 12μm / printing ink / / gas barrier nylon film 15μm / / easy peel sealant film 30μm ( / / indicates lamination by dry lamination) <Material> PET: Toyobo E5100 Nylon film: Mitsubishi Chemical's Supernil EPW Easy peel sealant: Toray Film Processing Co., Ltd. CF9501K2 Dry lamination adhesive: Mitsui Chemicals aliphatic ester urethane resin adhesive (Base agent Takelac A626 / hardener Takenate A50)

[0044] The sealing initiation temperature of this lid material was 160° C., so the sealing temperature was set to 170° C. 200 g of chilled pasta was filled into the container body, and the lid material was sealed under the lid material sealing conditions of 170° C., 0.3 MPa, and 1.5 seconds.

[0045] The ratio of the area of ​​the machined portion to the area of ​​the priority steam permeation region (one location) (machined area ratio) was changed to 10%, 30%, 50%, 70%, and 90%, respectively, to give Examples 2, 3, 4, 5, and 6. Each of these samples was evaluated for steam permeability when heated in a microwave oven and drop impact resistance.

[0046] <Vapor permeability evaluation> Three samples of each were heated in a 1600W microwave oven for one minute, and the presence or absence of steam passing through the machined steam port was confirmed. ○: Steam passes through the steam vent ×: Steam passes through a port other than the steam port

[0047] <Drop impact resistance evaluation> Two containers were stacked on top of each other and dropped vertically from a height of 80 cm onto the bottom of the container, and the existence of damage to the lid material or flange coming off was confirmed. Each test was carried out three times. ○: No damage to the lid or flange ×: Cover broken or flange missing

[0048] <Comparative Example 1> A sample was prepared in the same manner as in Example 1, except that the ratio of the area of ​​the machined portion to the area of ​​the preferential vapor passage region (one portion) (machined area ratio) was set to 4%, and was evaluated in the same manner.

[0049] <Comparative Example 2> A sample was prepared in the same manner as in Example 1, except that the ratio of the area of ​​the machined portion to the area of ​​the preferential vapor passage region (one portion) (machined area ratio) was 95%, and was evaluated in the same manner.

[0050] <Comparative Example 3> The packaging material described in Patent Document 1 was used to create the packaging material used for the lid, and was evaluated in the same manner.

[0051] The results are summarized in Table 1.

[0052] [Table 1]

[0053] The results in Table 1 demonstrate that the package according to the present invention has stable vapor permeability and resistance to drop impact. [Explanation of symbols]

[0054] 1...packaging 2. Container body 3. Flange section 4...Lid material 5. Synthetic resin stretched film base material 6. Gas barrier layer 7. Sealant layer 8...Priority vaporization area 9...Cutting section

Claims

1. A package formed by heat-sealing a lid having a sealant layer to a flange of a container body, When a container body filled with water and sealed with a lid is heated in a microwave oven, the flange part where the seal peels off due to the generated steam is defined as the priority steam passing area. The flange portion is partially machined in the preferential steam passage region, and the machined portion is not formed so as to communicate from the inside to the outside of the flange portion, and does not extend through the thickness of the flange portion; The ratio of the area of ​​the cut portion to the area of ​​the preferential vapor passage region is 5% or more and 90% or less; A package, characterized in that the sealant layer is heat-sealed to the flange portion so as to surround the machined portion.

2. 2. The packaging body according to claim 1, wherein the cover material has a synthetic resin stretched film substrate and an easily peelable sealant layer.

3. The packaging body according to claim 2 , wherein the lid material has a gas barrier layer.

4. The package according to any one of claims 1 to 3, characterized in that the container body has a rectangular shape, the preferential vapor passage regions are present at four corners, and at least one of the corners is subjected to cutting processing.

5. The package according to any one of claims 1 to 3, characterized in that the container body has an oval shape having two opposing straight sides, the preferential vapor passage regions are present in a total of four locations at both ends of the two straight sides, and at least one of the locations is subjected to cutting processing.

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