JP2021001008A - Package and package manufacturing method - Google Patents

Abstract

To provide a package limited in influence of the expansion of air in a head space cased by heat sterilization, and a method for manufacturing the package.SOLUTION: A container 1 is provided by molding the container 1 with a bottom part 2 projected outside from the container 1, and pressing the bottom part 2 from the outside of the container 1 to project it into the container 1. The bottom part 2 projects outside the container 1 so as to enlarge a storage space 1s upon reception of a force from the inside of the container 1, and projects into the container 1 so as to reduce the storage space 1s upon reception of a force from the outside of the container 1. A content 9 is stored in the storage space 1s of the container 1, the container 1 is sealed with a lid 8 so as to seal and pack the content 9 in the storage space 1s, and heat sterilization and subsequent cooling are performed, and thus a package 10 is provided.SELECTED DRAWING: Figure 4

Description

The present invention relates to a package and a method for producing the same, for example, a package for heat sterilization in which food is sealed and packaged as contents in a tray-shaped container, and a method for producing the same.

In order to reduce the burden of housework, demand for tray-type packaged foods (packaged foods such as prepared foods) is increasing at convenience stores and the like. The packaging of such foods is often heat sterilized (eg, boil heating or retort heating). However, in packaging using a tray-shaped container, the air in the head space (the space occupied by the contents in the storage space) between the container and the lid expands due to heat sterilization and the lid is peeled off from the container. It is necessary to pressurize during heat sterilization because there is a risk of causing it. Since pressure heat sterilization requires batch type (discontinuous type) equipment that can pressurize and heat in a closed space, for example, spray sterilization using heated steam at about 90 ° C. is continuously performed. The manufacturing process line cannot accommodate tray-shaped containers.

By increasing the adhesive strength between the container and the lid, it is possible to suppress the peeling of the lid without applying pressure. In that case, heat sterilization raises the air pressure in the headspace to expand the container, and subsequent cooling lowers the air pressure in the headspace to cause the container to contract. However, even if the container shrinks, it does not return to its original shape, and a dent may remain locally. In order to solve this problem, Patent Document 1 proposes a container having a shape having good shape resilience.

Japanese Patent No. 6492637

In the container described in Patent Document 1, emphasis is placed on suppressing the occurrence of local dents when the container returns to the pre-deformation state. Therefore, if the head space is large, the air in the head space is greatly expanded by heat sterilization, which greatly affects the lid and the container. For example, the lid may be deformed and peeled off from the container, or the container may be damaged (cracked or the like) due to the deformation of the lid.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a package having a small effect even if the air in the headspace expands due to heat sterilization, and a method for manufacturing the same. ..

In order to achieve the above object, the packaging body of the first invention is a packaging body compatible with heat sterilization treatment.
Contents that require heat sterilization, a tray-shaped container that has a storage space for the contents inside, and a lid that seals the container so that the contents are sealed and packaged in the storage space. And with
The container has a shape-variable portion that can be switched between a state of projecting out of the container and a state of projecting into the container.
When the shape-variable portion receives a force from the inside of the container, it protrudes out of the container so that the storage space becomes large, and when it receives a force from the outside of the container, it protrudes into the container so that the storage space becomes small. It is characterized in that it is in a state of being.

The package of the second invention is characterized in that, in the first invention, the container has a bottom portion formed of the shape-variable portion.

In the second invention, the package of the third invention is characterized in that the central portion of the bottom portion constituting the shape-variable portion is thinner than the peripheral portion.

In the second or third invention, the package of the fourth invention is formed so that the opening for taking in and out the contents in the container faces the bottom portion.
The container is characterized by including a flange portion formed so as to project outward from the peripheral edge of the opening, and a side surface portion connecting the bottom portion and the flange portion.

The package of the fifth invention is characterized in that, in the fourth invention, the container is a resin molded body in which the bottom portion, the flange portion, and the side surface portion are integrally formed.

In the package of the sixth invention, in any one of the first to fifth inventions, the shape-variable portion is in a state of protruding into the container in the container before the heat sterilization treatment. It is a feature.

The manufacturing method of the seventh invention is the manufacturing method of the package according to any one of the first to sixth inventions.
A container in which the variable shape portion protrudes outside the container is molded.
It is characterized in that the variable shape portion is pressed from the outside of the container so as to protrude into the container.

The manufacturing method of the eighth invention is the manufacturing method of the package according to any one of the above-mentioned first to sixth inventions.
A container in which the variable shape portion protrudes outside the container is molded.
By pressing the variable shape portion from the outside of the container, it is made to protrude into the container.
The contents are housed in the storage space,
The container is sealed with the lid so that the contents are hermetically packaged in the accommodation space.
It is characterized by heat sterilization and subsequent cooling.

According to the present invention, when the shape-variable portion receives a force from the inside of the container, it protrudes out of the container, and as a result, the accommodation space becomes large. Therefore, even if the air in the head space expands due to heat sterilization, The effect can be reduced. For example, it is possible to prevent the lid from peeling due to heat sterilization, and to prevent the container from being damaged (cracked or the like) due to the deformation of the lid.

The plan view which shows one Embodiment of a container and a package. FIG. 1 is a cross-sectional view taken along the line AA'in FIG. FIG. 1 is a sectional view taken along line BB'in FIG. The end view which shows the manufacturing process of the container and the packaging body of FIG. 1 in a schematic cross section. The end view which shows the state switching of the shape variable part in the container of FIG. 1 in a schematic cross section.

Hereinafter, the packaging body according to the embodiment of the present invention, the manufacturing method thereof, and the like will be described with reference to the drawings. The plan view of FIG. 1 shows a schematic configuration of the package 10. Further, a cross-sectional view taken along the line AA'in FIG. 1 is shown in FIG. 2, and a cross-sectional view taken along the line BB' in FIG. 1 is shown in FIG. In addition, in FIGS. 2 and 3, the corner rib 7 in FIG. 1 is not shown.

As shown in FIGS. 1 to 3, the package 10 includes a container 1, a lid 8, a content 9, and the like, and has a configuration corresponding to heat sterilization treatment. Here, since food (for example, delicatessen such as hamburger steak) is assumed as the content 9 arranged in the storage space 1s in the container 1, the package 10 corresponds to the packaged food, but the content 9 is It is not limited to food. Specific examples of the content 9 other than food include pharmaceuticals, medical devices, hygiene products, etc. that require heat sterilization treatment.

The container 1 has a tray shape capable of storing the contents 9 such as food in the internal storage space 1s. The container 1 is provided with a bottom portion 2, a flange portion 3, and a side surface portion 4 as main components, and is formed so that an opening 1a for inserting and removing the contents 9 faces the bottom portion 2. The opening 1a and the bottom 2 have a long shape in one direction, the flange 3 is formed so as to project outward from the peripheral edge of the opening 1a, and the bottom 2 and the flange 3 are connected by a side surface 4. doing.

The container 1 is a deformable resin molded body made of a thermoplastic resin such as polypropylene (PP), and the bottom portion 2, the flange portion 3, and the side surface portion 4 are integrally and thinly formed by a molding method such as injection molding or vacuum forming. (For example, thickness: 0.45 mm) is formed. Examples of the material of the container 1 include PP / EVOH (3%) / PP, PP containing a filler (the filler is made of an inorganic substance such as lime), and the like (EVOH: ethylene-vinyl alcohol plastic). Since the container 1 assumes food as the content 9 to be stored, it is compatible with heat sterilization treatment such as boiling heating (for example, spray sterilization using heated steam at 90 ° C.).

An annular portion 5 is provided as a part of the bottom portion 2 of the container 1. The outer shape of the annular portion 5, the inner shape of the flange portion 3 (the shape of the opening 1a), and the inner and outer shapes of the side surface portion 4 are substantially defined as having four curved corner portions and two straight portions adjacent thereto. It forms a rectangle (here, a substantially rectangular shape is assumed, but an elliptical shape or the like may be used), and they are in a substantially similar relationship with each other. Regarding the outer shape of the flange portion 3, the radius of curvature of the pair of diagonal portions is small so that the lid 8 can be easily peeled off by hand. When the package 10 is microwave-heated, the lid 8 is slightly peeled off from the corner having a small radius of curvature to enable safe steam removal during microwave oven heating.

The annular portion 5 is formed so as to project toward the outside of the container 1 (below the container 1) at the peripheral edge of the bottom portion 2 in order to improve the strength of the bottom portion 2 (FIGS. 2 and 3). Inside the annular portion 5, a side wall 5a and a bottom wall 5b having a track shape (that is, a composite shape of a rectangle and two semicircles) are located (FIG. 1), and the bottom wall 5b is above (opening 1a). The shape of the annular portion 5 protruding downward is formed by the shape of the annular portion 5 protruding downward (FIGS. 2 and 3).

As shown in FIG. 1, the annular portion 5, the side wall 5a and the bottom wall 5b constituting the bottom portion 2 are arranged so that the side wall 5a surrounds the bottom wall 5b and the annular portion 5 surrounds the periphery thereof. There is. Therefore, the bottom portion 2 can be deformed around the bottom wall 5b when it receives a force, and as shown in FIGS. 2 and 3, the bottom portion 2 protrudes out of the container 1 (long broken line) and protrudes into the container 1. It constitutes a variable shape part that can be switched from the state (solid line). With this structure capable of advancing and retreating, for example, when the bottom 2 receives a force (arrow md) from the inside of the container 1, the bottom 2 protrudes to the outside of the container 1 so that the accommodation space 1s becomes large, and the bottom 2 is from the outside of the container 1. When a force (arrow mu) is received, the accommodation space 1s is projected into the container 1 so as to be small.

In the bottom portion 2 protruding out of the container 1 (long broken line), the annular portion 5 is flat, but in the bottom portion 2 protruding inward of the container 1 (solid line), the annular portion 5 is a side wall 5a. Similarly, the curved surface is inclined, and the side wall 5a and the bottom wall 5b form a rounded curved surface. Therefore, there is no shape symmetry between the bottom 2 in the state of protruding out of the container 1 and the bottom 2 in the state of protruding into the container 1, and the bottom 2 in the state of protruding into the container 1 (solid line) is the container. 1 It takes a state of being symmetrical with respect to a state of protruding outward (long broken line) and a state of being further shifted into the container 1. Therefore, the head space HS in the container 1 can be made relatively small, and the loading of the container 1 can be easily stabilized. If the boundary between the annular portion 5 and the side wall 5a and the boundary between the side wall 5a and the bottom wall 5b are formed of a smooth curved surface, the occurrence of local dents can be effectively prevented.

A step portion 4a is formed on the side surface portion 4 of the container 1 near the upper portions of the long side and the short side of a substantially rectangular shape. Further, the side surface portion 4 is formed so that two corner ribs 7 (FIG. 1) project into the container 1 at each of four substantially rectangular corner portions. The step portion 4a and the corner rib 7 are provided to improve the strength of the side surface portion 4, and in particular, the corner rib 7 effectively acts to reinforce the corner portion of the side surface portion 4. Further, the side surface portion 4 is formed with a stack portion 4s for proper stacking of the containers 1. By locating the stack portion 4s at the boundary portion with the flange portion 3, the connection with the flange portion 3 is also strengthened.

The container 1 is sealed with a lid 8 so as to cover the opening 1a. The sealing is performed by adhering the lid 8 to the entire surface of the flange portion 3. The lid 8 has high flexibility that can be easily deformed, and has a base film forming the outermost layer and a sealant film (heat-adhesive resin film) located on the opening 1a side for sealing the container 1. ) And has a laminated structure.

Specific examples of the material of the lid 8 include laminated film materials such as PET (polyethylene terephthalate) 12 μm / ONY (biaxially stretched nylon) 15 μm / EP (easy peel sealant material) 50 μm, PET 12 μm / EP 50 μm, ONY 15 μm / EP 50 μm, and the like. .. The lid 8 is not limited to the resin film, and may be a multilayer base material in which each layer made of paper, metal foil, or the like is combined, and an adhesive may be used instead of the heat adhesive layer. When gas barrier properties are required, an aluminum foil layer or a thin-film vapor deposition film layer may be provided as the outermost layer or intermediate layer of the lid 8.

Here, a method for manufacturing the container 1 and the package 10 will be described. The end view of FIG. 4 shows a schematic cross section of the manufacturing process of the container 1 and the package (packaged food) 10. First, as shown in FIG. 4A, the container 1 in which the bottom portion 2 protrudes to the outside of the container 1 is molded by a molding method such as vacuum forming. Then, by pressing the bottom portion 2 from the outside of the container 1 by mechanical operation or manual operation, the bottom portion 2 is brought into a state of protruding into the container 1 as shown in FIG. 4 (B). As described above, the bottom 2 in the state of protruding into the container 1 (solid line) is in a state of being further shifted into the container 1 from a state symmetrical with respect to the state of protruding out of the container 1 (broken line). The head space HS occupying the accommodation space 1s is relatively small.

Next, as shown in FIG. 4C, the content (food or the like) 9 is placed in the storage space 1s of the container 1 through the opening 1a. Then, as shown in FIG. 4D, the lid 8 is arranged on the container 1 so as to cover the opening 1a, and the lid 8 is pressed against the flange portion 3 at a predetermined temperature (for example, about 150 to 300 ° C.). ) To heat. The lid 8 is made of the resin-made laminated film described above, and has a heat-adhesive sealant film on one side. The sealant film heat-bonds (heat seals) the lid 8 over substantially the entire upper surface of the flange portion 3.

By heat-adhering the lid 8 to the flange portion 3, the content 9 is hermetically packaged in a state of being arranged in the accommodation space 1s in the container 1. In this way, the tray-shaped container 1 having the storage space 1s inside, the content 9 housed in the storage space 1s and requiring heat sterilization, and the container 1 so that the content 9 is hermetically packaged. A packaging body 10 comprising a lid 8 for sealing is obtained.

When the package 10 in which the opening 1a of the container 1 is closed by the lid 8 is subjected to a heat sterilization treatment at about 90 ° C. in the steam sterilization step, the air pressure in the head space HS of the accommodation space 1s becomes high, and FIG. As shown in E), the bottom 2 and the lid 8 are deformed. That is, due to the force due to the expansion of the air in the head space HS, the bottom portion 2 is in a state of protruding to the outside of the container 1, and the lid 8 is in a state of being slightly inflated toward the outside of the container 1.

Since the bottom 2 of the container 1 is molded so as to protrude out of the container 1 (FIG. 4A), the shape of the container 1 at the time of molding (for example, during thermoforming in vacuum forming or the like) is stored. Therefore, even if the bottom 2 is in a state of protruding into the container 1 (FIG. 4 (D)), the bottom 2 is a force from the inside of the container 1 (that is, a force due to the expansion of air in the headspace HS due to heat sterilization). When it receives, it easily returns to the state (memory shape) protruding to the outside of the container 1. As a result, the amount of expansion of the air in the head space HS is absorbed by the deformation of the bottom 2 protruding out of the container 1. As a result, even if the air in the headspace HS expands due to heat sterilization, the lid 8 is deformed very little, and the lid 8 is not deformed so as to damage the package 10. For example, the lid 8 does not peel off from the container 1, and the container 1 is not damaged (cracked or the like) due to the deformation of the lid 8.

Then, when cooling is performed after heat sterilization, the air pressure in the head space HS of the accommodation space 1s becomes low, and the lid 8 and the container 1 return to their original shapes (FIG. 4D). In this way, even if the air in the headspace HS expands due to heat sterilization, the heat sterilized package 10 is obtained with little effect.

The state switching due to the deformation of the bottom portion 2 as a variable shape portion will be described in more detail. The end view of FIG. 5 shows the state switching of the bottom portions 2d and 2u in the container 1 in a schematic cross section. When the bottom 2d receives a force from the outside of the container 1 (arrow mu), it becomes a bottom 2u in a state of protruding into the container 1 so that the accommodation space 1s becomes smaller, and the bottom 2u becomes a force from the inside of the container 1 (arrow md). When it receives, it becomes the bottom 2d in a state of protruding to the outside of the container 1 so that the accommodation space 1s becomes large. The bottom portion 2u in the state of projecting into the container 1 is in a state of being further shifted into the container 1 from a state symmetrical with respect to the state of projecting out of the container 1 (broken line).

Even if the wall thickness of the container 1 before molding is uniform, the thickness of the bottom 2 can be changed by molding the container 1 by a molding method such as vacuum forming (FIG. 4 (A)). .. An example thereof is the bottom portion 2d in a state of protruding outside the container 1 in FIG. At the bottom 2d, the central portion is thinner than the peripheral portion. That is, the bottom wall 5b of the bottom portion 2d is thinner than that of the annular portion 5, and the side wall 5a is thinner as it approaches the bottom wall 5b side. Due to this non-uniform wall thickness, the bottoms 2d and 2u are easily deformed. That is, during heat sterilization, the bottom 2 easily protrudes out of the container 1, and during cooling, the bottom 2 easily protrudes into the container 1. Further, due to the non-uniform wall thickness, the bottom portion 2u shifts from a state symmetrical with respect to the state of projecting out of the container 1 (broken line in FIG. 5) to a state of projecting into the container 1.

Further, since the container 1 is stabilized by having a shape at the time of molding (shape memory), a force for returning to the original shape acts even if the container 1 is deformed, and it becomes easy to return to the shape at the time of molding. As a result, the bottom 2 from the state of protruding into the container 1 (bottom 2u in FIG. 5 and FIG. 4 (D)) to the state of protruding outside the container 1 (bottom 2d in FIG. 5 and FIG. 4 (E)). Is easy to deform. That is, during heat sterilization, the bottom portion 2 tends to protrude out of the container 1. Therefore, molding is performed assuming a deformed state during heat sterilization (FIG. 4 (A)), and the bottom portion 2 is inside the container 1 between the time when the container 1 is molded and the time when the lid 8 is heat-bonded to the flange portion 3. If it is set in a protruding state (FIGS. 4 (B) and 4 (C)), heat sterilization can be performed without any problem. Then, by cooling after heat sterilization, it is possible to return to the state before heat sterilization (FIG. 4 (D), the state at the time of display at the store).

According to the above embodiment, as described above, when the bottom portion 2 formed of the variable shape portion receives a force from the inside of the container 1, it protrudes out of the container 1, and as a result, the accommodation space 1s becomes large. Therefore, even if the air in the head space HS expands due to heat sterilization, the influence thereof can be reduced. For example, it is possible to prevent the lid 8 from being peeled off by heat sterilization, or to prevent the container 1 from being damaged (cracked or the like) due to the deformation of the lid 8.

In the container 1 described above, the shape-variable portion is formed on the bottom portion 2d, but the shape-variable portion may be formed on the side surface portion 4. Since the step portion 4a is formed on the side surface portion 4 as a part thereof, the deformation control of the side surface portion 4 is easy. For example, the side surface portion 4 protrudes to the outside of the container 1 so that the accommodation space 1s becomes larger when a force from the inside of the container 1 is received, and the container so that the accommodation space 1s becomes smaller when a force from the outside of the container 1 is received. If the state is such that it protrudes into 1, it becomes possible to cope with the heat sterilization treatment by changing the shape in the same manner as the bottom portion 2d.

1 Container 1a Opening 1s Storage space 2 Bottom (variable shape)
2d Bottom of the container protruding out of the container (variable shape)
2u Bottom of the container protruding (variable shape)
3 Flange part 4 Side part 4a Step part 4s Stack part 5 Ring part (variable shape part, peripheral part)
5a Side wall (variable shape)
5b Bottom wall (variable shape, center)
7 Corner rib 8 Lid 9 Contents (food)
10 Package (packaged food)
HS headspace

Claims (8)

A package that is compatible with heat sterilization
Contents that require heat sterilization, a tray-shaped container that has a storage space for the contents inside, and a lid that seals the container so that the contents are sealed and packaged in the storage space. And with
The container has a shape-variable portion that can be switched between a state of projecting out of the container and a state of projecting into the container.
When the shape-variable portion receives a force from the inside of the container, it protrudes out of the container so that the storage space becomes large, and when a force from the outside of the container is received, it protrudes into the container so that the storage space becomes small. A package characterized by being in a state of being in a state of being. The package according to claim 1, wherein the container has a bottom portion formed of the variable shape portion. The package according to claim 2, wherein the central portion of the bottom portion constituting the variable shape portion is thinner than the peripheral portion. In the container, an opening for taking in and out the contents is formed so as to face the bottom portion.
The packaging according to claim 2 or 3, wherein the container includes a flange portion formed so as to project outward from the peripheral edge of the opening, and a side surface portion connecting the bottom portion and the flange portion. body. The package according to claim 4, wherein the container is a resin molded body in which the bottom portion, the flange portion, and the side surface portion are integrally formed. The package according to any one of claims 1 to 5, wherein the shape-variable portion is in a state of protruding into the container before the heat sterilization treatment is performed. The method for manufacturing a package according to any one of claims 1 to 6.
A container in which the variable shape portion protrudes outside the container is molded.
A method for manufacturing a package, characterized in that the variable shape portion is pressed from the outside of the container so as to protrude into the container. The method for manufacturing a package according to any one of claims 1 to 6.
A container in which the variable shape portion protrudes outside the container is molded.
By pressing the variable shape portion from the outside of the container, it is made to protrude into the container.
The contents are housed in the storage space,
The container is sealed with the lid so that the contents are hermetically packaged in the accommodation space.
A method for producing a package, which comprises heat sterilization and subsequent cooling.

Images