Packaging film and sealed container

Abstract

To provide a packaging film which enables formation of a steam hole at a desired position in the packaging film.SOLUTION: A packaging film includes: a resin base material film having a first surface; and a first heat generation part and a second heat generation part which are arranged at an interval on the first surface. The first surface has: a first area in which the first heat generation part is printed; a second area in which the second heat generation part is printed; and a third area located between the first area and the second area. The first heat generation part and the second heat generation part include a heat-generating ink which absorbs microwaves to generate heat. The third area does not have a slit, but is configured to break as the first heat generation part and the second heat generation part generate heat.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a packaging film and a sealed container.

Background Art

[0002] Patent Document 1 discloses a package for storing frozen foods or chilled foods heated by a microwave oven. The package is, for example, a sealed container including a storage container and a packaging film for sealing the storage container. The packaging film includes a base material and a coating layer provided on the base material. The coating layer is made of an ink composition that generates heat by microwaves.

[0003] The coating layer of the packaging film in the sealed container generates heat by the microwaves of the microwave oven. At this time, the base material on which the coating layer is formed softens and shrinks. Further, the moisture of the contents in the sealed container becomes water vapor by the microwaves, and the internal pressure of the sealed container increases. As a result, steam holes are formed in the coating layer and the base material, and the water vapor in the sealed container escapes through the steam holes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technology of Patent Document 1 has the following problems. First, the melted base material may break into small pieces and fall off into the contents. Second, it is difficult to control the size and position of the pores in the coating layer, so it is difficult to appropriately control the amount of water vapor discharged. Third, when the internal pressure of the sealed container increases, there is a risk that the seal part between the storage container and the packaging film will peel off. Since unintentional pores are formed at the peeled part of the seal, water vapor is likely to be excessively discharged, and there is a risk that the contents cannot be heated appropriately.

[0006] One of the objects of the present invention is to provide a packaging film capable of forming pores at desired positions in the packaging film, and a sealed container including such a packaging film.

Means for Solving the Problems

[0007] (1) The packaging film according to one embodiment of the present invention includes a resin base film having a first surface, and a first heat generating portion and a second heat generating portion disposed at intervals on the first surface. The first surface has a first region where the first heat generating portion is printed, a second region where the second heat generating portion is printed, and a third region located between the first region and the second region. The first heat generating portion and the second heat generating portion contain heat generating ink that absorbs microwaves and generates heat, and the third region is configured to break along with the heat generation of the first heat generating portion and the second heat generating portion although it has no cut.

[0008] In the sealed container sealed by the packaging film described in the above (1), when the first heat generating part and the second heat generating part are heated by the microwave of the microwave oven, the resin-made first region and second region contract. At this time, a strong tensile stress acts on the third region sandwiched between the first heat generating part and the second heat generating part, so that the third region breaks and steam holes are formed in the third region. That is, by breaking the specific location of the third region sandwiched between the first heat generating part and the second heat generating part, the formation position of the steam holes in the packaging film can be controlled. Therefore, in the packaging film of the above form, it is easy to control the number of steam holes and the discharge amount of water vapor from the steam holes, and the contents can be appropriately heated.

[0009] The first region corresponding to the first heat generating part and the second region corresponding to the second heat generating part contract toward their respective centers. In the configuration of the prior art, when the base material melts at the position of the coating layer and steam holes are formed, the melted base material easily falls off into the sealed container as small pieces. In contrast, in the packaging film described in the above (1), since steam holes are formed in the third region as the first heat generating part and the second heat generating part generate heat, it is difficult for steam holes to be formed in the first region and the second region other than the third region. Therefore, in the sealed container sealed with the packaging film of the above form, the dropping of small pieces accompanying the formation of steam holes is suppressed.

[0010] The base film of the packaging film of the above form does not have a cut that serves as a starting point for breakage. Therefore, even if a mechanical load acts on the packaging film, the packaging film is not easily torn. For example, even if a plurality of sealed containers sealed with this packaging film are stacked and stored, it is difficult for holes to be formed in the packaging film of each sealed container, and the airtightness of the sealed container is easily maintained.

[0011] In the following description, the first heat generating part and the second heat generating part may not be distinguished and may simply be referred to as the heat generating part.

[0012] (2) In the packaging film described in (1) above, the first heat generating portion may have a first major axis, the second heat generating portion may have a second major axis, and the first major axis and the second major axis may be coaxially arranged. The distance S1 between the end points of the first major axis and the end points of the second major axis that are close to each other is shorter than the length L1 of the first major axis and the length L2 of the second major axis.

[0013] The first major axis is the longer one of the two central axes of the smallest rectangle circumscribing the first heat generating portion. The smallest rectangle is the rectangle with the smallest area among the rectangles circumscribing the first heat generating portion. That is, the first major axis is a straight line passing through the midpoint bisecting the short side of the smallest rectangle and extending parallel to the long side of the smallest rectangle. The first minor axis is the shorter one of the two central axes of the smallest rectangle. That is, the first minor axis is a straight line passing through the midpoint bisecting the long side of the smallest rectangle and extending parallel to the short side of the smallest rectangle. Similarly, in the second heat generating portion, among the two central axes of the smallest rectangle circumscribing the second heat generating portion, the longer central axis is the second major axis, and the shorter central axis is the second minor axis.

[0014] When the first heat generating portion having the first major axis generates heat and the first region contracts, the amount of contraction of the first region along the first major axis is larger than the amount of contraction of the first region along the first minor axis. Therefore, a large tensile stress acts in the vicinity of the end point of the first major axis in the third region. Similarly, when the second heat generating portion having the second major axis generates heat and the second region contracts, the amount of contraction of the second region along the second major axis is larger than the amount of contraction of the second region along the second minor axis. Therefore, a large tensile stress acts in the vicinity of the end point of the second major axis in the third region. In the configuration of (2) above, the first major axis of the first heat generating portion and the second major axis of the second heat generating portion are coaxially arranged, that is, the elongated first heat generating portion and the elongated second heat generating portion are arranged linearly side by side. Therefore, the tensile stress due to the contraction of the first region and the tensile stress due to the contraction of the second region concentrate in the third region, and pores are likely to be formed in the third region. Further, in the configuration of (2) above, since the distance S1 between the end point of the first major axis and the end point of the second major axis is shorter than the length L1 of the first major axis and the length L2 of the second major axis, pores are likely to be formed in the third region.

[0015] (3) In the packaging film described in (1) above, the first heat generating portion has a first major axis, the second heat generating portion has a second major axis, and the first extension line obtained by extending the first major axis and the second extension line obtained by extending the second major axis may intersect in the third region. Among the first extension line, the portion located farther from the first heat generating portion than the intersection with the second extension line, and among the second extension line, the portion located closer to the second heat generating portion than the intersection, the angle θ therebetween is 90° or less, and the distance S1 between the end points of the first major axis and the end points of the second major axis that are adjacent to each other is shorter than the length L1 of the first major axis and the length L2 of the second major axis.

[0016] Even in the configuration of (3) above, similar to the configuration of (2), the tensile stress due to the shrinkage of the first region and the tensile stress due to the shrinkage of the second region are likely to concentrate in the third region, and pores are likely to be formed in the third region.

[0017] (4) In the packaging film described in (2) or (3) above, the first heat generating portion and the second heat generating portion may be rectangular.

[0018] The shape of the heat generating portion having a major axis is not particularly limited. For example, it may be a wedge shape, an elliptical shape, or a rectangular shape. A rectangular heat generating portion is easy to form a plate for printing the heat generating portion. The heat generating portion may be formed by intaglio printing or by relief printing.

[0019] (5) In the packaging film described in any one of (2) to (4) above, the first major axis and the second major axis may be along the printing direction of the first heat generating portion and the second heat generating portion.

[0020] The printing direction can be identified by observing the tailing of the heat - generating part of the packaging film under a microscope or the like. Tailing is a phenomenon in which the ink thins and spreads like a streak at the rear end in the printing direction. When the first heat - generating part and the second heat - generating part are arranged side by side along the printing direction, tailing is formed in the third region. That is, it can be considered that the printing area between the first heat - generating part and the second heat - generating part extends by the amount of the tailing. Since tensile stress tends to concentrate in the third region due to tailing, the third region is likely to break.

[0021] (6) In the packaging film according to any one of (1) to (5) above, a plurality of pairs each composed of the first heat - generating part and the second heat - generating part may be provided.

[0022] When there is one third region in the packaging film, the amount of water vapor discharged from the steam holes in that third region is small, and the internal pressure of the sealed container tends to be high. Since the packaging film described in (6) above has a plurality of third regions, a plurality of steam holes are formed when heating by a microwave oven. Since the water vapor in the sealed container is quickly discharged through the plurality of steam holes, the internal pressure of the sealed container does not become too high. As a result, the seal part between the storage container and the packaging film is difficult to peel off, and it is difficult for unintended steam holes to be formed in the seal part.

[0023] (7) In the packaging film according to (6) above, the plurality of pairs may include different pairs adjacent to each other in a direction orthogonal to the direction in which the first heat - generating part and the second heat - generating part are arranged side by side.

[0024] In the packaging film described in (7) above, a plurality of pairs can be densely arranged in a specific narrow range in the base film rather than arranging a plurality of pairs in one direction. As a result, since a plurality of steam holes are formed in a specific narrow range of the packaging film, it is easy to control the amount of water vapor discharged.

[0025] (8) In the packaging film according to any one of (4) to (7) including the configuration of (2), (3), or (2) or (3), the distance S1 may be 0.8 mm or more and 2.0 mm or less.

[0026] If the distance S1 is 0.8 mm or more, the first heat generating part and the second heat generating part are sufficiently separated, so that it is possible to suppress the formation of small pieces of the base film that would fall off into the sealed container as if the first heat generating part and the second heat generating part were one large heat generating part. If the distance S1 is 2.0 mm or less, the stress concentrated in the third region tends to be high, and pores are likely to be formed in the third region.

[0027] (9) In the packaging film according to any one of (4) to (8) including the configuration of the above (2), (3), or (2) or (3), the length L1 and the length L2 may be 1.0 mm or more and 3.0 mm or less.

[0028] If the lengths L1 and L2 are each 1.0 mm or more, the shrinkage amount of the first region along the first major axis and the shrinkage amount of the second region along the second major axis are sufficiently large, and a sufficient tensile stress can be applied to the third region. If the lengths L1 and L2 are 3.0 mm or less, the printing length of the heat generating part can be shortened, pores are less likely to be formed at the positions of the first region and the second region, and the falling off of small pieces associated with the formation of pores at those positions is suppressed.

[0029] (10) In the packaging film according to any one of (1) to (9) above, the area of each of the first heat generating part and the second heat generating part is 1 mm 2 or more and 10 mm 2 or less. If the area of each of the first heat generating part and the second heat generating part is 1 mm 2 or more, the shrinkage amount of the first region and the shrinkage amount of the second region are sufficiently large, and a sufficient tensile stress can be applied to the third region. If the area of each of the first heat generating part and the second heat generating part is 10 mm 2 or less, pores are less likely to be formed at the positions of the first region and the second region, and the falling off of small pieces associated with the formation of pores at those positions is suppressed.

[0030] (11) In the packaging film according to any one of (1) to (10) above, the material of the base film may be polypropylene resin, polyethylene resin, polyethylene terephthalate resin, or polyamide resin.

[0031] Polypropylene resin (PP resin), polyethylene resin (PE resin), polyethylene terephthalate resin (PET resin), or polyamide resin (PA resin) is not only easily available but also easily ensures airtightness in a sealed container when sealed to a storage container.

[0032] (12) In the packaging film according to any one of (1) to (11) above, the average thickness of the base film may be 10 μm or more and 100 μm or less.

[0033] The base film with an average thickness of 10 μm or more has a predetermined strength and is thus not easily torn during storage of the sealed container. The base film with an average thickness of 100 μm or less does not have too high a strength, so steam holes are easily formed when heating the sealed container with a microwave oven.

[0034] (13) In the packaging film according to any one of (1) to (12) above, an additional film adhered to the first surface may be further provided.

[0035] For the additional film, a film having different properties from the base film can be used. For example, the additional film is a heat-sealing film. The packaging film provided with the additional film made of a heat-sealing film is easily heat-sealed to a storage container and easily improves the airtightness of the sealed container.

[0036] (14) In the packaging film according to any one of (1) to (13) above, a thin layer portion printed in the third region is provided, and the thin layer portion may contain the exothermic ink. The thickness of the thin layer portion is 1 / 10 or less of the thickness of each of the first exothermic portion and the second exothermic portion.

[0037] The thin layer portion is formed by printing a paint containing heat - generating ink on the third region so that it is thinner in thickness and smaller in area than the heat - generating portion. The thin layer portion is so thin that it is difficult to visually confirm.

[0038] When printing the first heat - generating portion and the second heat - generating portion with a gravure printing machine, by forming a thin layer portion in the third region, the wear amount of the doctor blade provided in the gravure printing machine can be reduced. This point will be described in detail in the embodiments.

[0039] (15) A sealed container according to an aspect of the present invention includes a storage container that stores contents heated by microwaves, and a packaging film that seals the contents in the storage container, and the packaging film is the packaging film according to any one of (1) to (14) above.

[0040] The above - mentioned sealed container includes a packaging film according to an aspect of the present invention. Since the base film of the packaging film has no cut that serves as a starting point of breakage, the packaging film is difficult to tear. Therefore, the airtightness of the above - mentioned sealed container is easily maintained.

[0041] In the above - mentioned sealed container, when heated in a microwave oven, steam holes are formed at a predetermined position of the packaging film, and it is difficult for steam holes to be formed at unintended positions. Therefore, the contents are easily heated appropriately.

Brief Description of the Drawings

[0042]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

Figure 9

Figure 10

Figure 11

MODE FOR CARRYING OUT THE INVENTION

[0043] Hereinafter, specific examples of the packaging film and the sealed container of the present invention will be described with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts. The sizes of the members shown in each drawing are represented for the purpose of clarifying the description and do not necessarily represent actual dimensions. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0044] <Embodiment 1> ≪Overall Configuration≫ The sealed container 1 shown in FIG. 1 includes a box-shaped storage container 9 and a resin packaging film 2 that seals the storage container 9. As shown in FIG. 2, the storage container 9 stores the contents 8 inside. The contents 8 are, for example, frozen foods or chilled foods. The contents 8 are heated together with the sealed container 1 by a microwave oven. The heating conditions of the microwave oven are, for example, 1500 W for a commercial microwave oven in a convenience store or the like, and 500 W for a household microwave oven.

[0045] ≪Storage Container≫ The storage container 9 is made of a heat-resistant material that is difficult to deform by heating in a microwave oven. The material of the storage container 9 is, for example, PET resin. The storage container 9 may be transparent or opaque. If the storage container 9 is transparent, the contents 8 can be confirmed from the outside of the storage container 9. If the storage container 9 is opaque, the contents 8 are shielded from light, and it is easy to suppress the deterioration of the contents 8.

[0046] The external shape of the storage container 9 is not particularly limited as long as it is box-shaped with an opening 90 at the upper end. The external shape of the storage container 9 in this example is generally a reverse truncated square pyramid shape. Different from this example, the external shape of the storage container 9 may be, for example, a reverse truncated cone shape, a cylindrical shape, or a prismatic shape.

[0047] A flange portion 9F is formed at the edge of the opening 90 of the storage container 9. The packaging film 2 is heat-sealed to the flange portion 9F.

[0048] <<Packaging Film>> The packaging film 2 in this example includes a base film 3, a first heat-generating portion 41, and a second heat-generating portion 42. In the following description, the first heat-generating portion 41 and the second heat-generating portion 42 may be referred to as the heat-generating portion 4 without distinction.

[0049] [Base Film] The base film 3 includes a first surface 3f and a second surface 3b opposite to the first surface 3f. A heat-generating portion 4, which will be described later, is printed on a part of the first surface 3f. In order to improve the adhesion of the heat-generating portion 4, the first surface 3f may be pre-treated. The pre-treatment is, for example, corona treatment, plasma treatment, or ozone treatment. In this example, the first surface 3f faces the outside of the storage container 9, and the second surface 3b faces the storage container 9.

[0050] The base film 3 has a size that covers the entire opening 90 of the storage container 9. The outer peripheral edge of the second surface 3b of the base film 3 is heat-sealed to the flange portion 9F of the storage container 9. The seal portion 10 where the outer peripheral edge and the flange portion 9F are heat-sealed maintains the airtightness of the sealed container 1 and suppresses the deterioration of the contents 8.

[0051] The material of the resin-based substrate film 3 is not particularly limited as long as it has a predetermined tensile strength and can maintain the airtightness of the sealed container 1. The material of the substrate film 3 is, for example, PP resin, PE resin, PA resin, or PET resin.

[0052] The average thickness of the substrate film 3 is, for example, 10 μm or more and 100 μm or less. Since the substrate film 3 with an average thickness of 10 μm or more has a predetermined strength, it is not easily torn during storage of the sealed container 1. Since the substrate film 3 with an average thickness of 100 μm or less does not have too high a strength, steam holes 39 (Fig. 4) are easily formed when the sealed container 1 is heated by a microwave oven. The steam holes 39 will be described later. The average thickness of the substrate film 3 may be 12 μm or more and 60 μm or less.

[0053] The average thickness of the substrate film 3 can be obtained, for example, by a commercially available thickness gauge, such as a non-contact thickness gauge that measures the thickness of a thin film by irradiating light in a wide wavelength region. In this example, the thickness of the portion of the substrate film 3 where the first heat generating portion 41 and the second heat generating portion 42 are not formed is measured by a thickness gauge, and the average thickness of the substrate film 3 is obtained by averaging these measured values. The number of measurement locations is, for example, 5 or more.

[0054] There are no cuts in the substrate film 3. In particular, there are no cuts in the third region 33 located between the first heat generating portion 41 and the second heat generating portion 42 of the substrate film 3. If there are cuts in the substrate film 3, for example, when a plurality of sealed containers 1 are stacked, the substrate film 3 may be torn starting from the cuts. Since there are no cuts in the substrate film 3 of this example, the substrate film 3 will not be torn to the extent that a plurality of sealed containers 1 are stacked.

[0055] [Heat generating part] Each of the first heating part 41 and the second heating part 42 contains a heat-generating ink that absorbs microwaves and generates heat. The frequency of microwaves is generally from 300 megahertz to 300 gigahertz. The frequency of a household, commercial, or industrial microwave oven is 2450 megahertz. The heat-generating ink contains a conductive material. The conductive material is, for example, carbon black, silver, aluminum, indium tin oxide, or a conductive organic compound. The conductive organic compound is, for example, at least one selected from the group consisting of polyanilines, polypyrroles, and polythiophenes. The resin is, for example, a polyvinyl alcohol resin.

[0056] The printing method of the heating part 4 is not particularly limited. If it is intaglio printing or letterpress printing, the heat-generating ink can be efficiently printed on the base material film 3 wound around the drum. For example, the heating part 4 may be printed by the gravure printing machine 7 shown in FIG. 3. The gravure printing machine 7 is a kind of intaglio printing machine.

[0057] The gravure printing machine 7 includes an ink pan 71, a finisher roll 72, a gravure roll 73, a doctor blade 74, and a pressure roll 75. The ink pan 71 stores the heat-generating ink 70. The finisher roll 72 attaches the heat-generating ink 70 stored in the ink pan 71 to the cells of the gravure roll 73. The cells are recesses that hold the heat-generating ink 70. The screen ruling of the cells is, for example, 100 lines or more. The screen ruling is the number of dot patterns arranged in a width of 1 inch. The gravure roll 73 applies the heat-generating ink 70 to the substrate film 3 being conveyed. The doctor blade 74 removes the excess heat-generating ink 70 attached to the gravure roll 73. The pressure roll 75 presses the substrate film 3 against the gravure roll 73. In FIG. 3, the rotation directions of the rolls 72, 73, and 75 are indicated by white arrows, and the conveyance direction of the substrate film 3 is indicated by a solid arrow. The substrate film 3 in this example is a substrate film 3 whose shrinkage rate in the conveyance direction is higher than the shrinkage rate in the direction orthogonal to the conveyance direction. In this example, the rotation direction of the gravure roll 73 and the conveyance direction of the substrate film 3 are the same. According to such a gravure printing machine 7, the heat-generating portion 4 can be continuously printed on the first surface 3f of the substrate film 3, and the packaging film 2 can be efficiently produced. Note that, different from this example, reverse gravure printing in which the rotation direction of the gravure roll 73 and the conveyance direction of the substrate film 3 are opposite may also be used.

[0058] The forms of the first heat-generating portion 41 and the second heat-generating portion 42 printed on the substrate film 3 by the gravure printing machine 7 will be described with reference to FIG. 4. The first heat-generating portion 41 and the second heat-generating portion 42 shown in FIG. 4 have a rectangular shape. In FIG. 4, the printing direction of the heat-generating portion 4 is indicated by a white arrow. This printing direction is opposite to the conveyance direction of the substrate film 3 in FIG. 3.

[0059] As shown in FIG. 4, the first heating part 41 has a first major axis 41L and a first minor axis 41S indicated by a dashed line. The first major axis 41L is the longer central axis among the two central axes of the smallest rectangle circumscribing the first heating part 41. The smallest rectangle is the rectangle with the smallest area among the rectangles circumscribing the first heating part 41. When the first heating part 41 is rectangular as in this example, the smallest rectangle circumscribing the first heating part 41 substantially coincides with the first heating part 41. The first minor axis 41S is the shorter central axis among the two central axes. The length L1 of the first major axis 41L and the length W1 of the first minor axis 41S can be measured, for example, by image analysis. The measurement of the lengths L1 and W1 may be performed manually using, for example, calipers. Here, in the gravure printing machine 7, a trailing edge where the ink thins and extends is formed at the rear end in the printing direction. The trailing edge is formed in a very short range downward from each lower edge of the heating part 4. The width of the trailing edge orthogonal to the printing direction is substantially equal to the length W1. That is, the length L1 is longer than the length of the major axis of the printing pattern corresponding to the first heating part 41 on the gravure roll 73. On the other hand, since no trailing edge is formed in the direction orthogonal to the printing direction, the length W1 of the first minor axis 41S is substantially the same as the length of the minor axis of the printing pattern corresponding to the first heating part 41 on the gravure roll 73.

[0060] The second heating part 42 has a second major axis 42L and a second minor axis 42S indicated by a dashed line. The definitions of the second major axis 42L and the second minor axis 42S are the same as the definitions of the first major axis 41L and the first minor axis 41S. The definitions of the length L2 of the second major axis 42L and the length W2 of the second minor axis 42S are also the same as the definitions of the length L1 and the length W1.

[0061] The first heating part 41 and the second heating part 42 shown in FIG. 4 are arranged on the same straight line. Specifically, the first major axis 41L and the second major axis 42L are coaxially arranged. Also, the first major axis 41L and the second major axis 42L are along the printing direction.

[0062] The first heating part 41 and the second heating part 42 are arranged at intervals. That is, the first heating part 41 and the second heating part 42 are independent. The area where the first heating part 41 is printed on the first surface 3f of the base material film 3 is the first area 31. The area where the second heating part 42 is printed on the first surface 3f is the second area 32. Also, the area located between the first area 31 and the second area 32 on the first surface 3f is the third area 33. The third area 33 in this example is an area surrounded by the extension lines of the two long sides of the rectangular first area 31 and the extension lines of the two long sides of the rectangular second area 32.

[0063] The size of the interval between the first heating part 41 and the second heating part 42 affects the formation of the steam holes 39 described later. In this specification, the size of the interval is evaluated by the distance S1. The distance S1 is the length between the endpoints of the first major axis 41L and the endpoints of the second major axis 42L that are close to each other. The preferred value of the distance S1 will be described later.

[0064] When the sealed container 1 provided with such a packaging film 2 is heated by a microwave oven, steam holes 39 are formed at the position of the third area 33 in the base material film 3. Specifically, the first heating part 41 and the second heating part 42 are heated by the microwave of the microwave oven, and the resin-made first area 31 and second area 32 shrink. At that time, a strong tensile stress acts on the third area 33 sandwiched between the first heating part 41 and the second heating part 42, so that the third area 33 breaks and steam holes 39 are formed in the third area 33. The heating conditions of the microwave oven for forming the steam holes 39 are, for example, 1500W×10 seconds, or 500W×40 seconds. The heating conditions of 1500W×10 seconds and 500W×40 seconds are substantially equivalent heating conditions. The heating time can be extended according to the type and amount of the content 8.

[0065] According to the above configuration, steam holes 39 are formed in the third region 33 sandwiched between the first region 31 and the second region 32, so that water vapor is discharged from the steam holes 39. By forming the steam holes 39 in the third region 33, the first region 31 and the second region 32 other than the third region 33 are not broken, and the steam holes 39 are not formed in the first region 31 and the second region 32. Therefore, it is easy to suppress the dropping of small pieces of the base film 3 due to the formation of the steam holes 39 in the first region 31 and the second region 32.

[0066] The first heating part 41 and the second heating part 42 are preferably arranged at the central part of the base film 3, that is, at the central part of the opening 90 of the storage container 9. When the internal pressure in the storage container 9 increases, the central part of the packaging film 2 bulges. Therefore, if the steam holes 39 are formed at the bulging part, the water vapor in the sealed container 1 can be efficiently discharged.

[0067] The steam holes 39 are preferably formed before the internal pressure of the sealed container 1 rises excessively. If the steam holes 39 are formed earlier than the internal pressure of the sealed container 1 rises so much as to peel off the adhesion of the seal part 10 due to the steam generated from the content 8 during heating in the microwave oven, the possibility that the seal part 10 between the storage container 9 and the packaging film 2 comes off is very low. Therefore, in the packaging film 2 of the sealed container 1 in this example, the position where the steam holes 39 are formed can be substantially limited to the third region 33, and it is easy to control the amount of water vapor discharged from the steam holes 39.

[0068] The printing patterns of the first heating part 41 and the second heating part 42 are not limited to the example shown in FIG. 4. The printing patterns may be patterns A to F shown in FIG. 5. The white arrows in FIG. 5 indicate the printing direction of the heating part 4.

[0069] In pattern A of FIG. 5, a first extension line 41Le obtained by extending the first major axis 41L and a second extension line 42Le obtained by extending the second major axis 42L intersect in the third region 33. Also, among the first extension line 41Le, the angle θ between a portion farther from the first heat generating portion 41 than the intersection with the second extension line 42Le and a portion of the second extension line 42Le located closer to the second heat generating portion 42 than the intersection is less than 90°. In pattern B, the first extension line 41Le and the second extension line 42Le intersect in the third region 33, and the angle θ is 90°. In pattern A and pattern B, the first heat generating portion 41 is arranged along the printing direction, and the trailing of the first heat generating portion 41 extends toward the third region 33. Steam holes 39 can also be formed in the third region 33 in these patterns A and B.

[0070] In pattern C, the first major axis 41L and the second major axis 42L are coaxially arranged, but the first major axis 41L and the second major axis 42L are inclined with respect to the printing direction. In pattern D, the first major axis 41L and the second major axis 42L are coaxially arranged, but the first major axis 41L and the second major axis 42L extend in a direction perpendicular to the printing direction. Steam holes 39 can also be formed in the third region 33 in these patterns C and D.

[0071] Pattern E includes two pairs 4P arranged in a direction perpendicular to the printing direction. Each pair 4P is composed of a first heat generating portion 41 and a second heat generating portion 42. The distance S2 between the left pair 4P and the right pair 4P is equal to or greater than the distance S1 in each pair 4P. In this configuration, steam holes 39 are likely to be formed at the positions of the two third regions 33, but it is extremely difficult to form steam holes 39 in the region between the adjacent pairs 4P, 4P having the distance S2.

[0072] In pattern F, two pairs 4P are arranged side by side in the printing direction. The second heat generating part 42 of the upper pair 4P also serves as the first heat generating part 41 of the lower pair 4P. Further, in pattern F, different pairs 4P are also arranged in a direction orthogonal to the printing direction. That is, in this configuration, four pairs 4P and four third regions 33 corresponding to each pair 4P are formed. Also in this configuration, steam holes 39 are likely to be formed at the positions of the third regions 33, but it is extremely difficult to form steam holes 39 in the region having the distance S2.

[0073] The lengths L1 and L2 described with reference to FIGS. 4 and 5 are, for example, 1.0 mm or more and 3.0 mm or less. If the lengths L1 and L2 are each 1.0 mm or more, the amount of shrinkage of the first region 31 along the first major axis 41L and the amount of shrinkage of the second region 32 along the second major axis 42L are sufficiently large, and a sufficient tensile stress can be applied to the third region 33. If the lengths L1 and L2 are 3.0 mm or less, it is difficult to form steam holes 39 at the positions of the first region 31 and the second region 32, and the dropping of small pieces due to the formation of the steam holes 39 at those positions is suppressed. The lengths L1 and L2 at which the steam holes 39 are likely to be formed vary depending on the material and thickness of the base film 3. The numerical values of the lengths L1 and L2 may be appropriately selected according to the material and thickness of the base film 3. The lengths L1 and L2 may be 1.5 mm or more and 3.0 mm or less, or 1.5 mm or more and 2.5 mm or less, or 2.0 mm or more and 2.5 mm or less.

[0074] The length W1 and the length W2 are each less than the length L1 and the length L2. The lengths W1 and W2 are, for example, 0.5 mm or more and 2.0 mm or less. The lengths W1 and W2 may be 0.8 mm or more and 1.5 mm or less, or 1.0 mm or more and 1.5 mm or less.

[0075] The distance S1 is, for example, less than the length L1 and less than the length L2. The distance S1 is, for example, 0.8 mm or more and 2.0 mm or less. If the distance S1 is 0.8 mm or more, the first heating part 41 and the second heating part 42 are sufficiently separated, so that it is possible to suppress the formation of small pieces of the base film 3 that would cause the first heating part 41 and the second heating part 42 to fall off the sealed container 1 as if they were one large heating part. If the distance S1 is 2.0 mm or less, the stress concentrated in the third region 33 tends to be high, and the steam holes 39 are likely to be formed in the third region 33. The distance S1 may be 1.0 mm or more and 1.5 mm or less, or 1.0 mm or more and 1.3 mm or less.

[0076] The thickness of the heating part 4 is, for example, 0.3 μm or more and 3.0 μm or less. If the thickness is 0.3 μm or more, the amount of the heating ink contained in the heating part 4 is sufficiently ensured. If the thickness is 3.0 μm or less, the heating part 4 does not become too thick.

[0077] A thin layer part 43 (Fig. 4) may be formed in the third region 33. The thin layer part 43 is printed, for example, following the first heating part 41 using the gravure printing machine 7 shown in Fig. 3. The second heating part 42 is printed following this thin layer part 43. That is, since the thin layer part 43 is printed by the gravure roll 73 in Fig. 3 in the same manner as the heating part 4, it contains the heating ink 70. However, the thickness of the thin layer part 43 is 1 / 10 or less of the thickness of the heating part 4. The thin layer part 43 containing the heating ink of such a thickness is so thin that it is difficult to visually confirm. Also, since the amount of the heating ink contained in the thin layer part 43 is small, when the packaging film 2 is heated in a microwave oven, the temperature of the thin layer part 43 does not become high enough to melt the third region 33. Furthermore, even if the thin layer part 43 generates heat, the heat generation does not substantially shrink the third region 33 and also does not substantially affect the shrinkage of the first region 31 and the second region 32 due to the heat generation of the heating part 4. The thickness of the thin layer part 43 may be 1 / 20 or less of the thickness of the heating part 4, or 1 / 30 or less.

[0078] The thin layer portion 43 of this example is printed by the gravure roll 73 so as to be thinner than the heat generating portion 4. Here, the cells arranged in the printing area of the heat generating portion 4 in the gravure roll 73 are defined as reference cells, and the cells arranged in the printing area of the thin layer portion 43 in the same gravure roll 73 are defined as additional cells. For example, the additional cells are formed such that the opening area of each additional cell is 1 / 10 or less of the opening area of each reference cell. The heat generating ink transferred from each additional cell to the third region 33 spreads thinly, and the thin layer portion 43 is formed in the third region 33. When the plate depth of the reference cells is the same as the plate depth of the additional cells, the volume of the heat generating ink held in the plurality of additional cells is 1 / 10 or less of the volume of the heat generating ink held in the plurality of reference cells. As a result, the thickness of the thin layer portion 43 becomes 1 / 10 or less of the thickness of the heat generating portion 4.

[0079] The thin layer portion 43 may be formed over the entire surface of the third region 33 or may be formed partially. When the opening area of the additional cells for printing the thin layer portion 43 becomes small, the amount of the heat generating ink transferred from each additional cell to the third region 33 is small, and the droplets of the heat generating ink adjacent to each other in the third region 33 may not connect. In that case, the thin layer portion 43 may be composed of a plurality of island portions independent of each other. Each island portion is formed by each additional cell.

[0080] As described above, by forming additional cells in the corresponding portion corresponding to the third region 33 in the gravure roll 73, the area where the doctor blade 74 contacts the gravure roll 73 in the corresponding portion can be reduced. As a result, the wear amount of the doctor blade 74 is reduced, and the life of the doctor blade 74 is extended.

[0081] ≪Others≫ As shown in FIGS. 1 and 2, the packaging film 2 may further include a printing layer 30 that covers the heat generating portion 4. The printing layer 30 has a size that covers the heat generating portion 4 on the first surface 3f. The printing layer 30 does not contain heat generating ink. The printing layer 30 of this example contains, for example, a white coloring agent to make the heat generating portion 4 and the steam holes 39 (FIG. 4) less conspicuous.

[0082] In this example, the printing layer 30 is formed on a part of the first surface 3f, but it may be formed on the entire first surface 3f. The printing layer 30 may be depicted with a product name, a product image, etc. When the sealed container 1 is sold in a state of being stored in a packaging package, if the product name and the product image are printed on the packaging package, the printing layer 30 may not be provided on the packaging film 2.

[0083] <Embodiment 2> The sealed container 1 of Embodiment 2 will be described with reference to FIG. 6. The packaging film 2 of the sealed container 1 in FIG. 6 includes an additional film 5 in addition to the configuration of Embodiment 1. The additional film 5 is adhered to the base film 3 by an adhesive layer 50. Specifically, the base film 3 printed with the heat generating portion 4 is adhered to the additional film 5 provided with the adhesive layer 50.

[0084] The orientation of the heat generating portion 4 of the sealed container 1 in FIG. 6 is different from that of Embodiment 1. Specifically, the first surface 3f of the base film 3 on which the heat generating portion 4 is formed is arranged facing the storage container 9. That is, the second surface 3b is arranged facing the outside of the storage container 9. The additional film 5 is arranged to cover the first surface 3f.

[0085] The additional film 5 is made of a material having better heat sealability than the base film 3. Therefore, the packaging film 2 of this example is easily heat-sealed to the flange portion 9F of the storage container 9, and the seal portion 10 between the packaging film 2 and the flange portion 9F is difficult to peel off. The material of the additional film 5 is, for example, an epoxy resin. Also, the material of the adhesive layer 50 is, for example, a polyurethane-based adhesive, an ester-based adhesive, or an ether-based adhesive.

[0086] In the configuration of Embodiment 2, the thickness of the packaging film 2 is increased by the additional film 5 and the adhesive layer 50. In such a configuration, for example, by increasing the tensile stress acting on the third region 33 by increasing the lengths L1 and L2 or decreasing the distance S1, steam holes 39 can be formed in all layers of the packaging film 2 corresponding to the third region 33.

[0087] The packaging film 2 of this example further includes a heat-sensitive layer 35. The heat-sensitive layer 35 is a layer containing ink that develops color upon heating. By pressing a thermal head (not shown) against the heat-sensitive layer 35, information such as the manufacturing date is printed. The heat-sensitive layer 35 is not essential.

[0088] <Embodiment 3> The sealed container 1 of Embodiment 3 will be described with reference to FIG. 7. In this example, a printing layer 30 is formed on the first surface 3f of the base film 3, that is, between the base film 3 and the heat-generating portion 4. In other words, the heat-generating portion 4 is printed on the first surface 3f of the base film 3 with the printing layer 30 interposed therebetween. Since the printing layer 30 is disposed on the outer side of the sealed container 1 rather than the heat-generating portion 4, the heat-generating portion 4 is not prominent. Also, since the printing layer 30 is disposed inside the packaging film 2, the printing layer 30 is not damaged even if alcohol for disinfection or the like is applied to the second surface 3b of the packaging film 2. For example, even if a product name or the like is depicted on the printing layer 30, the product name does not disappear.

[0089] Unlike FIG. 7, the printing layer 30 may be formed on the second surface 3b. In that case, the printing layer 30 and the heat-sensitive layer 35 are preferably formed so as not to overlap on the second surface 3b so that printing on the heat-sensitive layer 35 by the thermal head is not inhibited. When the printing layer 30 is printed on the entire second surface 3b, the heat-sensitive layer 35 is preferably formed on the printing layer 30 so that printing on the heat-sensitive layer 35 is not inhibited.

[0090] <Test Example 1> In Test Example 1, packaging films 2 of Sample No. 1 to Sample No. 15 were produced, and the influence of the heat-generating portion 4 on the formation of the steam holes 39 was examined.

[0091] ≪Sample No. 1≫ A packaging film 2 including the base film 3 and the additional film 5 shown in FIG. 6 was produced. The material of the base film 3 was a PET resin (E5202 manufactured by Toyobo Co., Ltd.), and the material of the additional film 5 was an epoxy resin (E7800TT manufactured by DIC Corporation). The average thickness of the base film 3 was 12 μm, and the average thickness of the additional film 5 was 60 μm.

[0092] The heating ink contained in the heating part 4 was the LG-MW heat agent manufactured by Tokyo Ink Co., Ltd. The conductive organic compound contained in the heating ink was carbon black, and the content of the organic compound was 90% by mass when the mass of the heating ink was 100% by mass.

[0093] For the printing of the heating part 4, the gravure printing machine 7 illustrated in FIG. 3 was used. A printing pattern for forming the heating part 4 shown in FIG. 4 was formed on the gravure roll 73. The screen ruling of the printing pattern was 100 lines, and the plate depth was 90 μm. The printing pattern is shown in the column of "Printing Pattern" in the matrix diagram of FIG. 8. The filled rectangular printing areas shown in the printing pattern include a large number of cells. The downward arrow in this column indicates the printing direction. The first heating part 41 was printed by the printing area arranged upstream in the printing direction, and the second heating part 42 was printed by the printing area arranged downstream. In the matrix diagram, "L" is the length of the printing area along the printing direction, "W" is the length of the printing area along the direction perpendicular to the printing direction, and "SL" is the length between two printing areas along the printing direction. "L" corresponds to the lengths L1 and L2 of the heating part 4. "W" corresponds to the lengths W1 and W2 of the heating part 4. "SL" corresponds to the distance S1. The length L of Sample No. 1 was 2.5 mm, the length W was 1 mm, and the distance SL was 1.5 mm.

[0094] As already described, trailing is formed in gravure printing. Therefore, the lengths L1 of the first heating part 41 and L2 of the second heating part 42 formed on the base film 3 are slightly longer than the length L of the printing area on the gravure roll 73. Therefore, the distance S1 on the base film 3 is also slightly shorter than the distance SL of the printing area on the gravure roll 73. On the other hand, since trailing is not formed in the direction perpendicular to the printing direction, the lengths W1 and W2 of the heating part 4 coincide with the length W of the printing area.

[0095] Next, a rectangular parallelepiped container made of PET was prepared, and water was put into the container. The amount of water was 60 milliliters when the heating condition described later was 1500 W, and 20 milliliters when it was 500 W. The volume of the container was 400 cm 3 3 was used. Packaging film 2 was placed over the opening of the container filled with water. An annular sealing material was attached to the edge of the container to seal the gap between the edge of the container and packaging film 2, thereby producing a test container simulating the sealed container 1. The test container was heated using a microwave oven, and it was examined whether steam holes 39 were formed in the packaging film 2. The heating condition of the microwave oven was 1500 W × 10 seconds. The presence or absence of the steam holes 39 was confirmed visually.

[0096] The presence or absence of the steam holes 39 in the table indicates whether the steam holes 39 are formed at the position of the distance S1, that is, in the third region 33. The results are also shown in the table of FIG. 8.

[0097] ≪Samples No. 2 to No. 10≫ Samples No. 2 to No. 10 have a different printing pattern from Sample No. 1. The printing patterns of Samples No. 2 to No. 10 are printing patterns for forming a plurality of pairs 4P such as patterns E and F in FIG. 5. The lengths L, W of the printing regions of the printing pattern and the distances SL, SW are as shown in FIG. 8 or FIG. 9. Here, 'SW' is the distance between the printing regions along the direction orthogonal to the printing direction. The distance SW corresponds to the distance S2. The distance S2 is the same as the distance SW. The configurations other than the printing pattern are the same as those of Sample No. 1.

[0098] In the tests using Samples No. 2 to No. 10, in addition to the heating condition of 1500 W × 10 seconds, the presence or absence of the formation of the steam holes 39 was also examined under the heating condition of 500 W × 40 seconds. The results are shown in FIGS. 8 and 9.

[0099] ≪Samples No. 11 to No. 15≫ Samples Nos. 11 to 15 were prepared by sealing a container with a packaging film 2 having the configuration shown in FIG. 7. The printing layer 30 disposed between the base film 3 and the heat generating portion 4 was formed of a white ink that does not contain heat generating ink. Samples Nos. 11 to 15 have a different printing pattern from Sample No. 1. The lengths L, W of the printing regions of the printing pattern and the distances SL, SW are as shown in FIG. 10. In FIG. 10, the formation range of the printing layer 30 is indicated by a two-dot chain line. It is considered that the formation of the printing layer 30 makes it difficult to form steam holes 39 in the packaging film 2.

[0100] For Samples Nos. 11 to 15 as well, it was examined whether steam holes 39 were formed under two heating conditions of 1500 W × 10 seconds and 500 W × 40 seconds. The results are shown in FIG. 10.

[0101] ≪Summary of test results≫ The column of "Presence or absence of steam holes" in FIGS. 8 to 10 indicates the presence or absence of steam holes 39 in the third region 33. "Yes" in Sample No. 1 indicates that steam holes 39 are formed in the third region 33. "Yes" in Samples Nos. 2 to 15 indicates that steam holes 39 are formed in at least one of the plurality of third regions 33. "No" indicates that no steam holes 39 are formed in any of the plurality of third regions 33. Here, although not shown in FIGS. 8 to 10, no steam holes 39 were formed at the position of the heat generating portion 4 in any of the samples. That is, in the base film 3, the first region 31 and the second region 32 corresponding to the heat generating portion 4 were not broken. Also, in any of the samples, no steam holes 39 were formed in the region of the distance S2. As an example, a photograph of the packaging film 2 of Sample No. 2 processed under the heating condition of 500 W × 40 seconds is shown in FIG. 11.

[0102] As shown in the result column of Sample No. 1 in Fig. 8, by forming two heat generating portions 4 arranged in the printing direction, steam holes 39 were formed in the third region 33 between the two heat generating portions 4. Also, as shown in the result columns of Samples No. 2, 3, 4, 5, 7, 8, and 9, when the lengths L1 and L2 in each of the plurality of pairs 4P were longer than the distance S1, steam holes 39 were formed in the third region 33. In these samples, a part of the third region 33 did not fall off into the container as small pieces. On the other hand, in Samples No. 6 and 10 where the lengths L1 and L2 in each of the plurality of pairs 4P were shorter than the distance S1, although wrinkles were formed in the third region 33, steam holes 39 were not formed.

[0103] As shown in the result column in Fig. 10, steam holes 39 were formed in the third region 33 in Samples No. 11 to No. 14, but steam holes 39 were not formed in the third region 33 in Sample No. 15. This is presumably because although the distance S1 of Sample No. 15 was shorter than the lengths L1 and L2, the distance S1 in Sample No. 15 was longer than the distance S1 in Samples No. 12 to No. 14.

[0104] From the above results, it became clear that by adjusting the lengths L1, L2, and the distance S1 of the first heat generating portion 41 and the second heat generating portion 42 according to the configuration of the packaging film 2, steam holes 39 can be formed only in the third region 33.

[0105] <Test Example 2> In addition to the same printing pattern as Sample No. 3, Samples No. 2 - 1, 2 - 2, and 2 - 3 in which a thin layer portion 43 was formed in the third region 33 by forming a plurality of additional cells between rectangular printing regions were produced. The total area of the additional cells per unit area in each of Sample No. 2 - 1, Sample No. 2 - 2, and Sample No. 2 - 3 was 1%, 2%, or 3% of the total area of the reference cells per unit area corresponding to the heat generating portion 4. The plate depth of the reference cells and the plate depth of the additional cells were the same. Therefore, the thickness of the thin layer portion 43 of Sample No. 2 - 1, Sample No. 2 - 2, and Sample No. 2 - 3 was 1 / 10 or less of the thickness of the heat generating portion 4.

[0106] The heating test was conducted on each sample under the same conditions as in Test Example 1. As a result, in each sample of Test Example 2, the same results as those of Sample No. 3 in Test Example 1 were obtained. That is, in each sample of Test Example 2, steam holes 39 were formed at the position of the third region 33, but a part of the third region 33 did not fall off into the container as small pieces.

Explanation of Signs

[0107] 1 Sealed container 10 Sealing part 2 Packaging film 3 Base film 3b Second surface, 3f First surface 30 Printing layer 31 First region, 32 Second region, 33 Third region 35 Heat-sensitive layer, 39 Steam hole 4 Heating part 4P Pair 41 First heating part, 41L First major axis, 41Le First extension line, 41S First minor axis 42 Second heating part, 42L Second major axis, 42Le Second extension line, 42S Second minor axis 43 Thin layer part 5 Additional film 50 Adhesive layer 7 Gravure printing machine 70 Heat-generating ink, 71 Ink pan, 72 Finisher roll 73 Gravure roll, 74 Doctor blade, 75 Pressure roll 8 Contents 9 Storage container 9F Flange part, 90 Opening L1, L2, W1, W2 Lengths S1, S2 Distances θ Angle

Claims

1. A resin-based substrate film having a first surface, a first heat generating portion and a second heat generating portion disposed at intervals on the first surface, wherein the first surface, a first region where the first heat generating portion is printed, a second region where the second heat generating portion is printed, and a third region located between the first region and the second region, wherein the first heat generating portion and the second heat generating portion contain a heat generating ink that absorbs microwaves and generates heat, wherein the third region is configured to break along with the heat generation of the first heat generating portion and the second heat generating portion although it has no cut, a packaging film.

2. The first heat generating portion has a first major axis, the second heat generating portion has a second major axis, the first major axis and the second major axis are coaxially arranged, and a distance S1 between an end point of the first major axis and an end point of the second major axis that are close to each other is shorter than a length L1 of the first major axis and a length L2 of the second major axis. The packaging film according to Claim 1.

3. The first heat generating portion has a first major axis, the second heat generating portion has a second major axis, a first extension line obtained by extending the first major axis and a second extension line obtained by extending the second major axis intersect in the third region, an angle θ between a portion of the first extension line that is farther from the first heat generating portion than the intersection with the second extension line and a portion of the second extension line that is closer to the second heat generating portion than the intersection is 90° or less, and a distance S1 between an end point of the first major axis and an end point of the second major axis that are close to each other is shorter than a length L1 of the first major axis and a length L2 of the second major axis. The packaging film according to Claim 1.

4. The first heat generating portion and the second heat generating portion are rectangular. The packaging film according to Claim 2 or Claim 3.

5. The first major axis and the second major axis are along the printing direction of the first heat generating portion and the second heat generating portion. The packaging film according to Claim 2 or Claim 3.

6. The packaging film according to any one of Claims 1 to 3, comprising a plurality of pairs each composed of the first heat generating portion and the second heat generating portion.

7. The plurality of pairs include different pairs adjacent to each other in a direction orthogonal to the direction in which the first heat generating portion and the second heat generating portion are arranged. The packaging film according to Claim 6.

8. The distance S1 is 0.8 mm or more and 2.0 mm or less. The packaging film according to Claim 2 or Claim 3.

9. The packaging film according to claim 2 or claim 3, wherein the length L1 and the length L2 are not less than 1.0 mm and not more than 3.0 mm.

10. The area of each of the first heat generating portion and the second heat generating portion is 1 mm ２ or more and 10 mm ２ or less. The packaging film according to any one of claims 1 to 3.

11. The packaging film according to any one of claims 1 to 3, wherein the material of the base film is polypropylene resin, polyethylene resin, polyethylene terephthalate resin, or polyamide resin.

12. The packaging film according to claim 11, wherein the average thickness of the base film is not less than 10 μm and not more than 100 μm.

13. Furthermore, the packaging film according to any one of claims 1 to 3, further comprising an additional film adhered to the first surface.

14. Comprising a thin layer portion printed in the third region, The thin layer portion contains the exothermic ink, The packaging film according to any one of claims 1 to 3, wherein the thickness of the thin layer portion is 1 / 10 or less of the thickness of each of the first exothermic portion and the second exothermic portion.

15. A storage container containing contents heated by microwave, And a packaging film for sealing the contents in the storage container, The packaging film is the packaging film according to any one of claims 1 to 3, Sealed container.

Images