Film, packaging container, and packaging container with content

Abstract

To provide a film that can stably discharge vapor, a packaging container, and a packaging container with contents.SOLUTION: A film 3, which is used in a packaging container 2, 2A, comprises a seal part 12c that is sealed on a flange 23 provided on an opening end of a container main body 13 with a bottom formed in a rectangular shape which is long in one direction or sealed overlapping thereon in the rectangular frame shape that is long in one direction, and a linear processing part 12a that forms a fractured part 12b that is fractured by an increase in inner pressure thereof. The processing part 12a inclines along a direction that is orthogonal to a diagonal line D of the seal part 12c or in a range of -30° and 30° with respect to the direction that is orthogonal to the diagonal line D.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a film, a packaging container, and a packaging container containing contents, which discharge steam generated when the packaged contents are heated in a microwave oven to the outside.

Background Art

[0002] Conventionally, a container that houses contents and heats the contents in a microwave oven in a sealed state has been known. When such a container heats the contents by a microwave oven, the internal pressure increases. For this reason, a container having means for automatically discharging steam and reducing the internal pressure during microwave heating is also known.

[0003] For example, Patent Document 1 discloses a cup container and a film capable of discharging steam during microwave heating by providing a fracture portion having an unoriented portion disposed opposite to each other with an oriented portion of a crystalline stretched and oriented film interposed therebetween.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the container that automatically discharges steam and reduces the internal pressure during the above-described microwave heating, the fracture portion may not fracture at a desired internal pressure. For this reason, due to the internal pressure of the container rising too much, bag breakage may occur.

[0006] Therefore, an object of the present invention is to provide a film, a packaging container, and a packaging container containing contents that can stably discharge steam.

Means for Solving the Problems

[0007] According to one aspect of the present invention, the film is sealed to a flange provided at an open end of a bottomed container body formed in a rectangular shape long in one direction, or is overlapped and sealed in a rectangular frame shape long in one direction, and includes a sealing portion, and a linear processed portion that forms a breaking portion that breaks due to an increase in internal pressure. The processed portion extends along a direction orthogonal to the diagonal line of the sealing portion, or is inclined within a range of -30° to 30° with respect to the direction orthogonal to the diagonal line.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a film, a packaging container, and a packaging container containing contents that can stably discharge steam.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the configuration of the packaged container 1 with contents according to the embodiment of the present invention will be described with reference to FIGS. 1 to 9. FIG. 1 is a perspective view showing the configuration of the packaged container 1 with contents according to the embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the container body 11 used for the packaged container 1 with contents. FIG. 3 is a plan view showing the configuration of the processed portion 12a of the lid 12 (film 3) used for the packaged container 1 with contents. FIG. 4 is an explanatory view schematically showing a plurality of examples and comparative examples of the packaged container 2 used in Evaluation Test 1. FIG. 5 is an explanatory view showing an example of the result of Evaluation Test 2, and FIGS. 6 to 8 are explanatory views showing an example of the analysis result of Evaluation Test 2. FIG. 9 is an explanatory view showing an example of the result of Evaluation Test 3, and FIGS. 10 to 11 are explanatory views showing an example of the analysis result of Evaluation Test 3.

[0011] As shown in FIG. 1, the packaged container 1 with contents includes a packaging container 2 and contents 100 accommodated in the packaging container 2. The packaged container 1 with contents is a packaging container for heating the contents 100 accommodated in the packaging container 2 by a microwave oven in a state where the packaging container 2 is sealed. Here, the contents 100 contain moisture that is heated by a microwave oven, and include, for example, foods cooked by heating with a microwave oven and articles such as wet wipes heated by a microwave oven.

[0012] The packaging container 2 is formed, for example, by using a film 3 having a processed portion 12a that breaks due to an increase in internal pressure as the lid 12, or by forming the film 3 into a bag shape. In the example of the present embodiment, the packaging container 2 includes a container body 11 and a lid 12 that seals the container body 11.

[0013] As shown in FIGS. 1 and 2, the container body 11 is a bottomed container capable of accommodating the contents 100. The container body 11 is a container such as a cup shape, a dish shape, or a tray shape formed in a rectangular shape that is long on one side. That is, the container body 11 extends in a direction in which a pair of long sides and a pair of short sides are orthogonal. Note that the corners continuous with the long sides and the short sides of the container body 11 may be inclined with respect to the long sides and the short sides, or may be formed in a curved surface shape. In the present embodiment, an example in which the corners of the long sides and the short sides of the container body 11 are formed in a curved surface shape will be described. The container body 11 includes a body portion 21, a bottom portion 22, and a flange 23. The container body 11 is formed of, for example, a resin material, and as a specific example, polypropylene (PP) or polystyrene (PS). The container body 11 is formed by vacuum forming or pressure-air forming. The container body 11 is set to have a size such that the area of the region defined by the outer peripheral edge of the flange portion 23a is 50 cm2 or more and 900 cm2 or less.

[0014] The lower end of the body portion 21 is closed by the bottom portion 22, and the upper end where the flange 23 is integrally formed is open. The body portion 21 is, for example, a rectangular shape that is long in one direction and extends in a direction in which a pair of long sides and a pair of short sides are orthogonal. Further, for example, the corners continuous with the long sides and the short sides of the body portion 21 may be inclined with respect to the long sides and the short sides, or may be formed in a curved surface shape. In the present embodiment, the body portion 21 is formed in a curved surface shape in which the corners are curved with a predetermined radius of curvature. The body portion 21 includes, for example, a first side portion 21a that is integrally continuous with the bottom portion 22 and whose width gradually decreases from the flange 23 side toward the bottom portion 22, and a second side portion 21b that connects the upper end of the first side portion 21a and the flange 23.

[0015] The first side portion 21a is formed in a tapered shape that is inclined with respect to the axial direction of the body portion 21 such that the width gradually decreases from the flange 23 side toward the bottom portion 22 side. The second side portion 21b is set to have a width larger than the width of the upper end of the first side portion 21a.

[0016] The bottom portion 22 is integrally formed at the lower end of the body portion 21. The bottom portion 22 is formed in a flat plate shape. For example, the central side may protrude toward the flange 23 side more than the outer edge side.

[0017] The flange 23 is integrally formed, for example, at the upper end (open end) of the barrel portion 21. The flange 23 is formed in an annular shape extending in a direction orthogonal or intersecting to the axial direction of the barrel portion 21 along the outer peripheral shape of the barrel portion 21 from the upper end edge of the barrel portion 21. For example, the flange 23 is in a rectangular shape that is long in one direction, and a pair of long sides and a pair of short sides extend in orthogonal directions. Also, for example, the flange 23 has corners continuous with the long sides and short sides inclined with respect to the long sides and short sides. The flange 23 includes, for example, a flat flange portion 23a, a skirt portion 23b extending downward from the outer edge of the flange portion 23a, and a hem portion 23c extending outward from the lower end of the skirt portion 23b.

[0018] The flange portion 23a is formed in an annular flat plate shape extending along the outer peripheral shape of the barrel portion 21. For example, the flange portion 23a is formed such that the width in a direction orthogonal to the extending direction is substantially constant, and is in a rectangular shape that is long in one direction. For example, the corners continuous with the long sides and short sides are inclined with respect to the long sides and short sides. The lid 12 is heat-sealed to the upper surface of the flange portion 23a. As a specific example, a jig for heat-sealing is disposed on the lower surface of the flange portion 23a, and the lid 12 is heated while being pressed against the upper surface of the flange portion 23a, so that the lid 12 is heat-sealed to the flange portion 23a. The flange portion 23a is formed, for example, to be slightly inclined such that the outer edge side is downward with respect to the vertical direction or with respect to a direction orthogonal to the vertical direction. The flange portion 23a is formed in an annular flat plate shape.

[0019] The skirt portion 23b is formed in a ring shape and extends downward from the outer edge of the flange portion 23a. The length of the skirt portion 23b is preferably 3 mm or more and 15 mm or less. More preferably, the length of the skirt portion 23b is 4 mm or more and 9 mm or less. Here, the length of the skirt portion 23b is the length along the outer surface extending downward of the skirt portion 23b from the ridge portion between the flange portion 23a and the skirt portion 23b to the ridge portion between the skirt portion 23b and the hem portion 23c. Further, the length of the skirt portion 23b may be different, for example, on the long side and the short side. In this case, for example, the length of the skirt portion 23b on the long side is longer than the length of the skirt portion 23b on the short side.

[0020] The hem portion 23c is formed in a ring shape and extends outward from the lower end of the skirt portion 23b. For example, the hem portion 23c extends outward along a direction orthogonal to the axial direction of the container body 11 from the lower end of the skirt portion 23b. The length of the hem portion 23c is preferably 1.5 mm or more and 10 mm or less. More preferably, the length of the hem portion 23c is 2.0 mm or more and 5.0 mm or less. Here, the length of the hem portion 23c is the length along the upper surface in the extending direction of the hem portion 23c from the ridge portion between the skirt portion 23b and the hem portion 23c to the end portion of the hem portion 23c. For example, the hem portion 23c is formed when the container body 11 is trimmed from a sheet material of a resin material which is a molding material during the molding of the container body 11.

[0021] Further, for example, the angle between the flange portion 23a and the skirt portion 23b is set to be 90 degrees or more and 120 degrees or less. Here, the angle between the flange portion 23a and the skirt portion 23b is the angle between the lower surface of the flange portion 23a and the inner surface of the skirt portion 23b. Also, for example, the angle between the skirt portion 23b and the hem portion 23c is set to be 60 degrees or more and 120 degrees or less. Here, the angle between the skirt portion 23b and the hem portion 23c is the angle between the outer surface of the skirt portion 23b and the upper surface of the hem portion 23c.

[0022] The container body 11 configured as described above can be formed in a stackable manner because the width of the body portion 21 decreases downward. For example, a predetermined interval, e.g., an interval of 3 mm or more, is formed in the axial direction between the lower end of the skirt portion 23b of the upper container body 11 and the upper surface of the flange portion 23a of the lower container body 11 when the container bodies 11 are stacked adjacent to each other. Further, the plurality of container bodies 11 may have a plurality of ribs for stacking and reinforcement in order to provide a predetermined interval between adjacent container bodies 11 when stacked.

[0023] The lid 12 is formed, for example, by a film 3 having a resin layer capable of heat-sealing on the flange portion 23a. The lid 12 has a processing portion 12a that forms a breaking portion 12b that breaks when the internal pressure of the container body 11 with the heat-sealed lid 12 rises and reaches a predetermined internal pressure or higher. The processing portion 12a is formed in a part of the lid 12, and the breaking portion 12b is formed by breaking due to the rise in internal pressure, and a steam outlet through which steam escapes is formed by this breaking portion 12b. Various techniques can be applied to the processing portion 12a. That is, the processing portion 12a formed on the lid 12 may have, for example, a plurality of portions 12a1 with relaxed orientation, and a breaking portion may be formed between these portions 12a1 with relaxed orientation, as long as it is configured to break due to the rise in internal pressure and form the breaking portion 12b serving as a steam outlet. Alternatively, the processing portion 12a may be formed by reducing the strength of a part of the lid 12, and configured to break earlier than other parts of the lid 12 when the internal pressure rises, and form the breaking portion 12b in a part of the processing portion 12a.

[0024] Further, the lid 12 (film 3) is formed by a multilayer film having a seal layer on one main surface, for example, the main surface on the container body 11 side. The lid 12 is welded to the flange portion 23a of the container body 11 by heat-sealing or the like, thereby forming a seal portion 12c. Since the seal portion 12c is an area welded to the flange portion 23a, in the present embodiment, it is formed in an annular rectangular frame shape that is long in one direction and has the same shape as the flange portion 23a, for example, a pair of long sides and a pair of short sides.

[0025] The processing portion 12a is formed in a long linear shape in one direction. Also, the processing portion 12a may be configured to be formed in a single long linear shape in one direction, or may be configured to have a plurality of portions 12a1 formed in a long linear shape in one direction and arranged side by side in that one direction.

[0026] In the present embodiment, as shown in FIG. 3, the processing portion 12a is formed by arranging a plurality of, for example, four portions 12a1 formed in a long linear shape in one direction side by side, and a break portion 12b is formed between adjacent portions 12a1. As an example, the portion 12a1 is formed, for example, by heating the film 3 (lid 12) linearly with a laser beam or the like to cause non-crystallization and relieve or lose the orientation. In other words, the processing portion 12a is formed in a long shape in one direction and by providing three non-processed sites partially in the middle part in the longitudinal direction.

[0027] Such a processing portion 12a that is long in one direction is arranged such that its longitudinal direction is perpendicular to the diagonal line D of the seal portion 12c of the lid 12 (i.e., 90° with respect to the diagonal line D), or is inclined at a predetermined angle, for example, an angle of ±30°, with respect to the direction perpendicular to the diagonal line D. Preferably, the longitudinal direction is arranged along the short side of the seal portion 12c of the lid 12 or is inclined within a range of ±30° as a predetermined angle with respect to the short side of the seal portion 12c. In other words, the angle of the longitudinal direction of the processing portion 12a with respect to the direction perpendicular to the diagonal line D of the seal portion 12c is set in the range of -30° to 30° (0° ± 30°). More preferably, the angle of the longitudinal direction of the processing portion 12a with respect to the direction perpendicular to the diagonal line D of the seal portion 12c is set in the range of -15° to 15° (0° ± 15°).

[0028] Further, the processing portion 12a is an area inside the inner peripheral edge of the seal portion 12c in the lid 12 (film 3), and in the direction along the diagonal line D of the seal portion 12c, from a distance of 20% of the distance from the corner of the inner peripheral edge of the seal portion 12c to the center of the diagonal line D of the seal portion 12c, at least a part is provided on the diagonal line D within the range up to the center of the diagonal line D. That is, the processing portion 12a is inside the inner peripheral edge of the seal portion 12c, and at least a part is arranged in the 80% area on the central side in the direction of the diagonal line D of the seal portion 12c.

[0029] That is, as shown in each of the embodiments of FIGS. 1 and 4, in the area within the inner peripheral edge of the seal portion 12c, when assuming that there is a diagonal line D, the processing portion 12a is in a posture within an angle range of -30° to 30° with respect to the direction orthogonal to the diagonal line D, and is arranged within a range of 20% or more of the range from the corner of the inner peripheral edge of the seal portion 12c to the center in the direction of the diagonal line D.

[0030] The packaging container 1 containing the contents configured in this way has, in the area inside the inner peripheral edge of the seal portion 12c of the lid 12 (film 3), the longitudinal direction of the processing portion 12a within a range of 0° ± 30° with respect to the direction orthogonal to the diagonal line D of the seal portion 12c, and is provided in the range from a distance of 20% to the center in the direction along the diagonal line D from the corner of the inner peripheral edge of the seal portion 12c. With such a configuration, when the contents 100 in the packaging container 1 containing the contents are heated by a microwave oven, steam is generated from the moisture contained in the contents 100, the internal pressure rises, and the lid 12 (film 3) expands. When the lid 12 (film 3) expands, the linear processing portion 12a expands in the direction orthogonal to the longitudinal direction of the processing portion 12a, breaks at the breaking portion 12b, and the steam in the packaging container 2 escapes to the outside to perform steam venting.

[0031] When the lid 12 (film 3) extends evenly, by forming the processed part 12a at 0° with respect to the direction orthogonal to the diagonal line D of the seal part 12c or by forming it to be inclined at an angle of ±30° with respect to the direction orthogonal to the diagonal line D, the length by which the processed part 12a extends in the short side direction of the processed part 12a becomes longer, and the breakage part 12b becomes easier to break. Thus, by providing the lid 12 (film 3) such that the longitudinal direction of the processed part 12a is within the range of 0° ± 30° with respect to the direction orthogonal to the diagonal line D, the breakage part 12b can be surely broken, and the packaging container 1 containing the contents can stably discharge steam.

[0032] Also, when the internal pressure of the packaging container 2 increases, deformation is likely to occur on the long side of the packaging container 2, and deformation is likely to occur on both the long side and the short side toward the central side rather than the corner side. That is, the long side of the packaging container 2 has lower strength than the short side, and both the long side and the short side of the packaging container 2 have lower strength at the central side than at the corner side. Therefore, when the lid 12 deforms into a dome shape due to an increase in internal pressure, the long side deforms, and there is a possibility that the central side deforms on both the long side and the short side. For this reason, the expansion of the lid 12 expands more on the corner side than on the central side of each side of the seal part 12c in the vicinity of the seal part 12c, and expands as a whole at the central side of the internal region of the seal part 12c. For this reason, the lid 12 tends to extend in the direction of the diagonal line D of the seal part 12c. Therefore, the lid 12 (film 3) of the packaging container 2 of the embodiment is formed by making the linear processed part 12a parallel or inclined within a predetermined range with respect to the direction orthogonal to the diagonal line D of the seal part 12c, so that the breakage part 12b becomes easier to break.

[0033] Also, when the lid 12 deforms into a dome shape, in the direction of the diagonal line D, the range from the position 20% separated from the corner to the center has a greater elongation than near the corner of the seal part 12c. Therefore, by arranging the processed part 12a in the range from the position 20% separated from the corner to the center, the processed part 12a easily extends in the short side direction, so that the breakage part 12b becomes easier to break. Therefore, the packaging container 2 can stably discharge steam.

[0034] In addition, in the packaging container 1 containing the contents, as the internal pressure rises, the lid 12 deforms into a dome shape. Generally, however, the long side of the flange portion 23a may deform more than the short side. However, by providing the skirt portion 23b on the flange 23 of the packaging container 2, the strength of the flange 23 can be improved. Therefore, when the contents 100 are heated in a microwave oven and the lid 12 expands into a dome shape, it is possible to suppress the flange 23 from deforming due to the stress generated by the deformation of the lid 12, and the rupture portion 12b can be stably ruptured. Further, since the strength of the skirt portion 23b can be improved by providing the hem portion 23c that extends outward from the lower end of the skirt portion 23b on the flange 23, the strength of the flange 23 can be further improved, and the deformation of the flange 23 can be further suppressed.

[0035] Next, as an example of the evaluation test of the container body 11 configured as described above, Evaluation Test 1 and Evaluation Test 2 will be described with reference to FIGS. 4 to 8. Note that the evaluation test is for clarifying the characteristics of the container body 11 of the present embodiment, and the scope of the present invention is not limited to the following examples.

[0036] [Evaluation Test 1] As Evaluation Test 1, the packaging container 2 of Example 1 and the container of Comparative Example 1 were produced, and samples in which the lid 12 was heat-sealed with the container body 11 of Example 1 and the container body 11 of Comparative Example 1 in an empty state were produced. Further, the longitudinal length W1 of the flange 23 and the lid 12 of the container body 11 of the packaging container 2 was set to 153 mm, the lateral length W2 of the flange 23 and the lid 12 was set to 117 mm, the longitudinal length W3 at the inner peripheral edge of the seal portion 12c of the lid 12 was set to 134 mm, and the lateral length W4 at the inner peripheral edge of the seal portion 12c was set to 98 mm.

[0037] The lid 12 used a PET(16) / easy peel(30) film. Four portions 12a1 were formed in the processed portion 12a formed on the lid 12 so that three rupture portions 12b were formed, and the longitudinal length of the processed portion 12a, that is, the distance between the ends located outside the outermost portion 12a1 in the arrangement direction, was set to 46 mm.

[0038] As shown in FIG. 4, for the packaging container 2 of Example 1, the angle of the long processing part 12a in one direction was set as the direction (0°) along the direction perpendicular to one diagonal line D of the seal part 12c, and the center of the longitudinal direction of the processing part 12a was set as the position of 40% of the distance from the corner part to the center. Here, the distance from the corner part to the center is the distance within the inner peripheral edge of the seal part 12c. Specifically, it is the length from the end (corner part) of the diagonal line D on the inner peripheral edge of the seal part 12c to the center of the diagonal line D. Also, as shown in FIG. 4, for the packaging container of Comparative Example 1, the angle of the long processing part 12a in one direction was set as the direction along one diagonal line D of the seal part 12c, that is, 90° with respect to the direction perpendicular to the diagonal line D, and the center of the longitudinal direction of the processing part 12a was set as the position of 40% of the distance from the corner part to the center.

[0039] Then, three samples of the packaging containers 2 of Example 1 and Comparative Example 1 were formed. For each packaging container 2 of each example and each comparative example, after immersing the lid 12 in the water surface of a constant temperature water bath set at 90°C using a seal tester (FKT - 100J) manufactured by Sanken Science, a needle was inserted from the bottom of the container body 11 to inject air into the packaging container 2, and the opening pressure (kPa) at the fracture part 12b of the processing part 12a was measured respectively.

[0040] [Results of Evaluation Test 1] The opening pressures P (kPa) of the three fracture parts 12b measured three times each in Example 1 and Comparative Example 1 are described for reference in each example of FIG. 4. Note that the opening pressure in FIG. 4 is the pressure value when at least any one of the three fracture parts 12b breaks. As shown in FIG. 4, the opening pressures P (kPa) of the fracture parts 12b measured three times in Example 1 were 8.5 kPa, 8.5 kPa, and 8.5 kPa. In contrast, the opening pressures P (kPa) of the fracture parts 12b measured three times in Comparative Example 1 were 12 kPa or more, 12 kPa or more, and 12 kPa or more.

[0041] As is clear from these results, the opening pressure P of the packaging container 2 of Example 1 was P ≤ 9 kPa, while that of the packaging container 2 of Comparative Example 1 was P > 9 kPa. As is also clear from the opening pressure P, the packaging container 2 of Example 1 can reduce the internal pressure required for the opening (rupture) of the rupture portion 12b, and it was revealed that the rupture of the rupture portion 12b can be easily and surely performed.

[0042] [Evaluation Test 2] Next, as Evaluation Test 2, an analysis was performed on models of the packaging container 2 of Example 2 and the packaging container 2 of Comparative Example 2 below. The model analysis was performed using LS-DYNA manufactured by Ansys. As the analysis conditions, the thickness t1 of the packaging container 2 was set to 0.50 mm and the elastic modulus was set to 1300 MPa. Among the thickness t2 of the lid 12, the thickness of the processed portion 12a was set to 0.05 mm and the elastic modulus was set to 15 MPa, and the thickness of the portion (non-processed portion) other than the processed portion 12a of the lid 12 was set to 0.05 mm and the elastic modulus was set to 1600 MPa. Further, in the processed portion 12a, four portions 12a1 having a length of 11 mm in the longitudinal direction and a width of 0.5 mm were arranged along the longitudinal direction, and the interval between adjacent portions 12a1 was set to 1.0 mm.

[0043] Also, similar to the packaging container 2 of Example 1, the packaging container 2 of Example 2 had the angle of the long processed portion 12a in one direction along the direction (0°) perpendicular to one diagonal line D of the seal portion 12c, and the center of the longitudinal direction of the processed portion 12a was set at the position 40% of the distance from the corner to the center.

[0044] Similar to the packaging container 2 of Comparative Example 1, the packaging container 2 of Comparative Example 2 had the angle of the long processed portion 12a in one direction along one diagonal line D of the seal portion 12c, that is, 90° with respect to the direction perpendicular to the diagonal line D, and the center of the longitudinal direction of the processed portion 12a was set at the position 40% of the distance from the corner to the center.

[0045] Then, a part of the container body 11 of the packaging containers 2 of Example 2 and Comparative Example 2 was fixed, and the internal pressure was increased at 300 kPa / s. Then, the maximum value of the stress generated between the portions 12a1 of the processed portion 12a, that is, at the rupture portion 12b, was plotted.

[0046] Also, the maximum principal stress σ (MPa) and the elongation δ (mm) in the short direction orthogonal to the longitudinal direction of the portion 12a1 of the processed portion 12a were determined when the pressure P inside the packaging container 2 was 10 kPa.

[0047] [Results of Evaluation Test 2] Hereinafter, the results of Evaluation Test 2 will be described with reference to FIGS. 5 to 8. FIG. 5 is a graph showing the relationship between the pressure (kPa) inside the packaging container 2 and the stress (MPa) at the fracture portion 12b. FIG. 6 is an explanatory diagram showing the stress distribution of the lid 12 and the maximum principal stress of the processed portion 12a when the pressure P inside the packaging container 2 is 10 kPa. FIG. 7 is an explanatory diagram showing the deformation of the processed portion 12a and the stress distribution in the processed portion 12a when the pressure P inside the packaging container 2 is 10 kPa, and FIG. 8 is an explanatory diagram showing the deformation of one fracture portion 12b of the processed portion 12a and the stress distribution at the fracture portion 12b when the pressure P inside the packaging container 2 is 10 kPa.

[0048] As shown in FIG. 5, a higher stress occurred in the fracture portion 12b of the packaging container 2 of Example 2 than in the packaging container of Comparative Example 2. From this, it can also be seen that by making the processed portion 12a of the present embodiment, suitable stress is generated in the processed portion 12a due to the increase in the internal pressure of the packaging container 2, and the fracture of the fracture portion 12b is improved.

[0049] Also, as shown in FIGS. 6 to 8, in the packaging container 2 of Example 2, the maximum principal stress σ was 326.2 MPa, and the maximum elongation δ in the short direction of the portion 12a1 of the processed portion 12a was 0.61 mm.

[0050] On the other hand, in the packaging container 2 of Comparative Example 2, the maximum principal stress σ was 195.0 MPa, and the maximum elongation δ in the short direction of the portion 12a1 of the processed portion 12a was 0.24 mm.

[0051] In the packaging container 2 of Example 2, it was revealed that the maximum principal stress σ and elongation δ in the processed portion 12a were greater than those in the processed portion 12a of the packaging container of Comparative Example 2. Thus, also from the analysis results, by making the processed portion 12a of the present embodiment, suitable stress is generated in the processed portion 12a due to the increase in the internal pressure of the packaging container 2, and it can be understood that the breakage of the broken portion 12b becomes good.

[0052] [Evaluation Test 3] Next, as Evaluation Test 3, the models of the packaging containers 2 of Examples 3 to 6 below were analyzed, and the maximum principal stress σ and elongation δ were compared according to the distance from the corner of the seal portion 12c. The model analysis was performed using LS-DYNA manufactured by Ansys. As the analysis conditions, similar to Evaluation Test 2, the thickness t1 of the packaging container 2 was set to 0.50 mm, the elastic modulus was set to 1300 MPa, and among the thickness t2 of the lid 12, the thickness of the processed portion 12a was set to 0.05 mm, the elastic modulus was set to 15 MPa, the thickness of the portion other than the processed portion 12a (non-processed portion) of the lid 12 was set to 0.05 mm, and the elastic modulus was set to 1600 MPa. Further, in the processed portion 12a, four portions 12a1 having a length of 11 mm in the longitudinal direction and a width of 0.5 mm were arranged along the longitudinal direction, and the interval between adjacent portions 12a1 was set to 1.0 mm.

[0053] Also, similar to the packaging container 2 of Example 1, the packaging container 2 of Example 3 had the angle of the long processed portion 12a in one direction along the direction (0°) perpendicular to one diagonal line D of the seal portion 12c, and the center of the longitudinal direction of the processed portion 12a was set at a position 20% of the distance from the corner to the center.

[0054] Also, similar to the packaging container 2 of Example 1, the packaging container 2 of Example 4 had the angle of the long processed portion 12a in one direction along the direction (0°) perpendicular to one diagonal line D of the seal portion 12c, and the center of the longitudinal direction of the processed portion 12a was set at a position 40% of the distance from the corner to the center.

[0055] Further, similar to the packaging container 2 of Example 1, the packaging container 2 of Example 5 had the angle of the long processing portion 12a in one direction set as the direction (0°) along the direction perpendicular to one diagonal line D of the seal portion 12c, and the center of the longitudinal direction of the processing portion 12a was set at the position of 70% of the distance from the corner portion to the center.

[0056] Further, similar to the packaging container 2 of Example 1, the packaging container 2 of Example 6 had the angle of the long processing portion 12a in one direction set as the direction (0°) along the direction perpendicular to one diagonal line D of the seal portion 12c, and the center of the longitudinal direction of the processing portion 12a was set at the center of the seal portion 12c (100% of the distance from the corner portion to the center).

[0057] That is, the processing portion 12a of the packaging container 2 of Example 3 was closest to the corner portion of the seal portion 12c, and the processing portion 12a of the packaging container 2 of Example 6 was at the center of the inner region of the seal portion 12c.

[0058] Then, a part of the container body 11 of the packaging containers 2 of Examples 3 to 6 was fixed, and the internal pressure was increased at 300 kPa / s. Then, the maximum value of the stress generated at the break portion 12b, that is, between the portions 12a1 of the processing portion 12a, was plotted.

[0059] Also, the maximum principal stress σ (MPa) and the elongation δ (mm) in the short direction perpendicular to the longitudinal direction of the portion 12a1 of the processing portion 12a were obtained when the pressure P inside the packaging container 2 was 10 kPa.

[0060] [Results of Evaluation Test 3] Hereinafter, the results of Evaluation Test 2 will be described with reference to FIGS. 9 to 11. FIG. 9 is a graph showing the relationship between the pressure (kPa) inside the packaging container 2 and the stress (MPa) at the break portion 12b. FIGS. 10 and 11 are explanatory diagrams showing the stress distribution of the lid 12 and the maximum principal stress of the processing portion 12a when the pressure P inside the packaging container 2 is 10 kPa.

[0061] As shown in Fig. 9, the highest stress occurred at the fracture part 12b in the packaging container 2 of Example 3. Next, high stress occurred at the fracture part 12b in the packaging container 2 of Example 4. In Example 5 and Example 6, although lower than that in the packaging container 2 of Example 4, substantially the same stress occurred at the fracture part 12b. From this, it can be seen that the stress occurring at the fracture part 12b increases from the central side to the corner of the seal part 12c.

[0062] Also, as shown in Fig. 10, in the packaging container 2 of Example 3, the maximum principal stress σ was 377.5 MPa, and the maximum elongation δ in the short direction of the portion 12a1 of the processed part 12a was 0.78 mm.

[0063] As shown in Fig. 10, in the packaging container 2 of Example 4, the maximum principal stress σ was 326.2 MPa, and the maximum elongation δ in the short direction of the portion 12a1 of the processed part 12a was 0.61 mm.

[0064] As shown in Fig. 11, in the packaging container 2 of Example 5, the maximum principal stress σ was 350.4 MPa, and the maximum elongation δ in the short direction of the portion 12a1 of the processed part 12a was 0.58 mm.

[0065] As shown in Fig. 11, in the packaging container 2 of Example 6, the maximum principal stress σ was 374.4 MPa, and the maximum elongation δ in the short direction of the portion 12a1 of the processed part 12a was 0.57 mm.

[0066] As described above, the maximum principal stress σ and the elongation δ were suitable values in any of the packaging containers 2 of Examples 3 to 6. Regarding the elongation δ, it tended to gradually decrease from the corner side (Example 3) to the center (Example 6) of the seal portion 12c. The maximum principal stress was the highest at the center (Example 6), but when deviating from the center, it tended to gradually decrease from the corner side (Example 3) to the center side (Example 5). For this reason, when providing the processing portion 12a at a position excluding the center (Example 6) within the inner peripheral edge of the seal portion 12c of the packaging container 2, it is preferable to arrange at least a part of the processing portion 12a in the range of 20% to 70% of the length from the end (corner) of the diagonal line D to the center of the diagonal line D.

[0067] As described above, according to the lid 12 (film 3) used for the packaging container 1 containing the content according to the present embodiment, when the internal pressure of the packaging container 2 increases, the breaking portion 12b breaks preferably, so that the vapor can be discharged stably.

[0068] Note that the present invention is not limited to the above-described embodiments. For example, in the above example, the packaging container 2 is described as being formed by sealing the lid 12 formed by the container body 11 and the film 3, but it is not limited thereto. For example, as shown in FIG. 12, the packaging container 1 containing the contents may be formed into a bag shape or a pouch shape as the packaging container 2A by bending a single film 3 and heat-sealing the edges, or by stacking two or more films 3 and heat-sealing the edges. When a plurality of films 3 are used for the packaging container 2A, the processing portion 12a is formed on any one of the films 3. Further, the packaging container 2 is heat-sealed in a rectangular frame shape that is long in one direction, or a seal portion 12c with three sides heat-sealed is formed, and the longitudinal direction of the processing portion 12a is within a range of 0° ± 30° with respect to the direction orthogonal to the diagonal D of the inner peripheral edge of the seal portion 12c, and in the direction along the diagonal D of the inner peripheral edge of the seal portion 12c, it is provided in a range of 20% or more of the distance from the corner to the center. The packaging container 2 formed by welding one or more films 3 configured as described above, like the packaging container 2 having the container body 11 and the lid 12 described above, can stably discharge steam because the breaking portion 12b preferably breaks when the internal pressure of the packaging container 2 rises.

[0069] Note that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist thereof at the implementation stage. Also, the respective embodiments may be implemented in appropriate combinations, and in that case, the combined effects can be obtained. Furthermore, the above embodiments include various inventions, and various inventions can be extracted by combinations selected from the plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, if the problem can be solved and the effects can be obtained, the configuration with these deleted constituent elements can be extracted as an invention.

Explanation of Reference Numerals

[0070] 1…Packaging container with contents, 2, 2A…Packaging containers, 3…Film, 11…Container body, 12…Lid, 12a…Processing part, 12a1…Part, 12b…Breaking part, 12c…Sealing part, 21…Barrel part, 21a…First side part, 21b…Second side part, 22…Bottom part, 23…Flange, 23a…Flange part, 23b…Skirt part, 23c…Hem part, 100…Contents.

Claims

1. A seal part that is sealed to a flange provided at an open end of a bottomed container body formed in a rectangular shape long in one direction, or is overlapped and sealed in a rectangular frame shape long in one direction; A linear processed part that forms a breaking part that breaks due to an increase in internal pressure; Comprising; The processed part is a film that extends along a direction perpendicular to the diagonal of the seal part or is inclined within a range of -30° to 30° with respect to the direction perpendicular to the diagonal.

2. The film according to claim 1, wherein at least a part of the processed part is arranged in a range of 20% or more of the length from the end of the diagonal to the center of the diagonal.

3. The film according to claim 2, wherein at least a part of the processed part is arranged in a range of 20% to 70% of the length from the end of the diagonal to the center of the diagonal.

4. The film according to claim 1, wherein the processed part is inclined within a range of -15° to 15° with respect to the direction perpendicular to the diagonal.

5. A bottomed container body formed in a rectangular shape long in one direction, having one end open in the axial direction, and having a flange provided at the opening; A lid formed of the film according to any one of claims 1 to 4, wherein the seal part is sealed to the flange; A packaging container comprising.

6. The packaging container according to claim 5, wherein the container body has a skirt part extending toward the bottom direction at the periphery of the flange and having a length of 3 mm to 15 mm in the axial direction of the container body.

7. The packaging container according to claim 6, wherein the container body has a hem part extending outward from the outer peripheral edge of the skirt part and having a length of 1.5 mm to 10 mm in a direction perpendicular to the axial direction of the container body.

8. The packaging container according to claim 5; Contents provided in the packaging container; A packaging container with contents comprising.

9. A packaging container formed in a bag shape by overlapping the films according to any one of claims 1 to 4 and sealing them at the seal part.

10. The packaging container according to claim 9; Contents provided in the packaging container; A packaging container with contents comprising.

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