JP7619078B2 - Tray-shaped container - Google Patents

Description

The present invention relates to a tray-shaped container.

Conventionally, plastic tray-shaped containers have been used, which are capable of storing food without requiring any special processing on the inner surface.
In recent years, in response to the trend toward eliminating or reducing plastic, there has been a shift from plastic tray-type containers to paper tray-type containers.
When food is placed in a paper tray-like container, oil dripping from the food will seep into the paper, so it has been proposed to laminate the paper with a resin such as polyethylene or polypropylene in advance, or to laminate and adhere a resin film layer to the inner surface of the tray-like container (see, for example, Patent Documents 1 to 3).

Japanese Patent Application Publication No. 10-114327 Special Publication No. 2013-545675 Special table 2015-528762 publication

Although resin films for forming the resin film layer have been developed that are stretchable and less likely to break, there is a problem that the resin film layer breaks when the resin film layer is laminated and bonded to the inner surface of the paper tray-shaped container depending on the shape of the tray-shaped container, and there is also a problem that the resin film layer breaks when the container is subjected to an impact.
Therefore, the objective of the present invention is to provide a tray-shaped container that prevents the resin film layer from breaking when the resin film layer is laminated and bonded to the inner surface of the opening side of the paper layer, and that can prevent the resin film layer from breaking even when an impact is applied.

As a result of intensive research, the inventors have found that in a tray-like container having an open top, a paper layer based on paperboard, and a resin film layer laminated and bonded to the inner surface of the paper layer on the opening side, the tray-like container having a bottom and side surfaces erected from the bottom surface, the side surfaces including main side surfaces erected from the bottom surface and directly connected to the periphery of the opening, the taper angle of the main side surface, the depth of the tray-like container, the basis weight of the paperboard, the Taber stiffness of the paper layer to which the resin film layer on the main side surface is laminated and bonded, and the adhesive strength between the paper layer on the main side surface and the resin film layer laminated and bonded to the paper layer are within specific ranges.
That is, the present invention relates to the following <1> to <7>.
<1> A tray-shaped container having an open top surface and including a paper layer based on paperboard and a resin film layer laminated and bonded to the inner surface of the paper layer on the opening side, the tray-shaped container having a bottom surface and a side surface extending from the bottom surface, the side surface including a main side surface extending from the bottom surface and directly connected to a periphery of the opening, the main side surface having a taper angle of 3.5° to 18°,
a tray-like container having a depth of 16 mm or more and 90 mm or less, a basis weight of the paperboard of 200 g/m2 or ^more and 600 g/m2 ^or less, a Taber stiffness of the paper layer to which the resin film layer is laminated and bonded on the main side of the container of 3 mN·m or more and 70 mN·m or less in both a first direction and a second direction perpendicular to the first direction, and an adhesive strength between the paper layer on the main side of the container and the resin film layer laminated and bonded to the paper layer of 0.40 N/25 mm or more in at least one of the first direction and the second direction perpendicular to the first direction.
<2> The tray-shaped container according to <1>, further comprising a flange surface disposed on the periphery of the opening.
<3> The tray-shaped container according to <2>, wherein the flange surfaces are on the same plane.
<4> The tray-shaped container according to any one of <1> to <3>, wherein the paper layer is bonded by the resin film layer.
<5> The tray-shaped container according to any one of <2> to <4>, wherein the paper layers at the four corners of the flange surface are separated and the paper layers at the four corners are joined by the resin film layer.
<6> The tray-shaped container according to any one of <1> to <5>, wherein the side surface further includes a sub-side surface that is erected from the bottom surface and is not directly connected to the periphery of the opening.
<7> The tray-shaped container according to any one of <1> to <6>, wherein the paperboard is made of at least one layer and at most eight layers.

The present invention provides a tray-shaped container that can prevent the resin film layer from breaking when the resin film layer is laminated and bonded to the inner surface of the opening side of the paper layer, and can also prevent the resin film layer from breaking even when an impact is applied.

FIG. 1 is a perspective view of a tray-shaped container according to a first embodiment of the present invention. FIG. 2 is a plan view showing the tray-shaped container of FIG. FIG. 3 is a cross-sectional view showing the AA section of FIG. FIG. 4 is a plan view of a blank sheet for the container body of FIG. FIG. 5 is a perspective view of a tray-shaped container according to a second embodiment of the present invention. FIG. 6 is a plan view showing the tray-shaped container of FIG. FIG. 7 is a plan view of a blank sheet for the container body of FIG. 8(a) to (d) are explanatory diagrams of modified examples of the tray-shaped container. FIG. 9 is a perspective view of a mold (a molding die) for manufacturing the tray-shaped container of FIG. FIG. 10 is an explanatory diagram of a method for manufacturing the tray-shaped container of FIG.

The present invention will be described in detail below.
In this specification, the definitions that are considered to be preferable may be adopted arbitrarily, and the combination of preferable definitions may be considered to be more preferable.
In addition, in this specification, the lower limit and upper limit described in stages for the preferred numerical range (for example, the range of the content, etc.) can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to obtain "10 to 60". In addition, in the numerical range described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples.
In addition, the term "taper angle" in this specification refers to the inclination angle of the main side surface with respect to the normal line (see "taper angle A" in Figure 3). When there are multiple main side surfaces, there will be multiple taper angles for one tray-shaped container, and the average value of these multiple taper angles will be the taper angle.
Furthermore, in this specification, the "depth of the tray-shaped container" means the minimum distance from the periphery (portion) of the opening to the bottom surface (see "depth B" in Figure 3).

[Tray-shaped container]
The tray-shaped container of the present invention is a tray-shaped container having an open top and a paper layer based on paperboard and a resin film layer laminated and bonded to the inner surface of the paper layer on the opening side, the tray-shaped container having a bottom and a side surface extending from the bottom, the side surface including a main side surface extending from the bottom surface and directly connected to the periphery of the opening, the taper angle of the main side surface being 3.5° or more and 18° or less, the depth of the tray-shaped container being 16 mm or more and 90 mm or less, and the basis weight of the paperboard being 200 g/m2 ^{or more} and 600 g/m2 or more. the Taber stiffness of the paper layer to which the resin film layer is laminated and bonded at the main side is 3 mN· ^m or more and 70 mN·m or less in both of the first direction and the second direction perpendicular to the first direction, and the adhesive strength between the paper layer at the main side and the resin film layer laminated and bonded to the paper layer is 0.40 N/25 mm or more in at least one of the first direction and the second direction perpendicular to the first direction. The tray-shaped container is capable of preventing the resin film layer from breaking when the resin film layer is laminated and bonded to the inner surface of the opening side of the paper layer, and of preventing the resin film layer from breaking even when an impact is applied.

The taper angle of the main side surface in the tray-shaped container of the present invention is not particularly limited as long as it is 3.5° or more and 18° or less, but it is preferably 4° or more, more preferably 4.5° or more, even more preferably 5° or more, and is preferably 17° or less, more preferably 16° or less, and even more preferably 15° or less.
In the tray-shaped container of the present invention, the taper angle of the main side surface is 3.5° or more, which makes it easier to laminate and adhere the resin film layer to the inner surface of the opening side of the paper layer and prevents the resin film layer from breaking. In addition, in the tray-shaped container of the present invention, the taper angle of the main side surface is 18° or less, which prevents the resin film layer from breaking even when an impact is applied.

The depth of the tray-shaped container of the present invention is not particularly limited as long as it is 16 mm or more and 90 mm or less, but it is preferably 17 mm or more, more preferably 18 mm or more, even more preferably 20 mm or more, and it is preferably 87 mm or less, more preferably 84 mm or less, and even more preferably 80 mm or less.
By making the depth of the tray-shaped container of the present invention 16 mm or more, the usefulness as a container can be improved, such as by improving the strength of the container and increasing the food filling capacity, etc. By making the depth of the tray-shaped container of the present invention 90 mm or less, it is possible to prevent the resin film layer from breaking when laminating and adhering the resin film layer to the inner surface of the opening side of the paper layer.

The Taber stiffness of the paper layer to which the resin film layer is laminated and bonded on the main side of the tray-shaped container of the present invention is not particularly limited, as long as it is 3 mN·m or more and 70 mN·m or less in both the first direction and the second direction perpendicular to the first direction, but is preferably 3.2 mN·m or more, more preferably 3.4 mN·m or more, even more preferably 3.6 mN·m or more, and is preferably 69.8 mN·m or less, more preferably 69.5 mN·m or less, and even more preferably 69.2 mN·m or less.
The Taber stiffness of the paper layer to which the resin film layer is laminated and bonded on the main side surface of the tray-like container of the present invention is 3 mN·m or more in both the first direction and the second direction perpendicular to the first direction, so that the shape of the tray is easily maintained, and in the form in which the resin film layer is laminated and bonded on the inner surface of the opening side of the paper layer, even if an impact is applied, the resin film layer can be prevented from peeling off from the paper layer and the resin film layer can be prevented from breaking. In addition, the Taber stiffness of the paper layer to which the resin film layer is laminated and bonded on the main side surface of the tray-like container of the present invention is 70 mN·m or less in both the first direction and the second direction perpendicular to the first direction, so that when the paper is bent, the stress that tries to return to the original unfolded state is weakened, and in the form in which the resin film layer is laminated and bonded on the inner surface of the opening side of the paper layer, even if an impact is applied, the resin film layer can be prevented from peeling off from the paper layer and the resin film layer can be prevented from breaking.
The Taber stiffness of the paper layer to which the resin film layer is laminated and bonded is measured by the method described in the Examples section below.

The adhesive strength between the paper layer on the main side surface of the tray-shaped container of the present invention and the resin film layer laminated and bonded to the paper layer is not particularly limited as long as it is 0.40 N/25 mm or more in at least one of the two directions, the first direction and the second direction perpendicular to the first direction, but is preferably 0.43 N/25 mm or more, more preferably 0.46 N/25 mm or more, and even more preferably 0.50 N/25 mm or more. Furthermore, a higher adhesive strength is preferable, and there is no particular upper limit, but it is preferably 10 N/25 mm or less when the resin film layer is peeled off from the paper layer after use of the container.
Since the adhesive strength between the paper layer on the main side of the tray-shaped container of the present invention and the resin film layer laminated and bonded to the paper layer is 0.40 N/25 mm or more in at least one of the two directions, a first direction and a second direction perpendicular to the first direction, it is possible to prevent the resin film layer from peeling off from the paper layer when the resin film layer is laminated and bonded to the inner surface of the opening side of the paper layer, and it is also possible to prevent the resin film layer from breaking and to prevent the resin film layer from breaking even when an impact is applied.
The adhesive strength between the paper layer and the resin film layer laminated and bonded to the paper layer is measured by the method described in the examples below.

The tray-shaped container of the present invention preferably further has a flange surface disposed around the periphery of the opening. By further having a flange surface disposed around the periphery of the opening, it is possible to perform a top seal on the opening of the tray-shaped container after the food is placed in the tray-shaped container.

In addition, it is preferable that the flange surfaces of the tray-like container of the present invention are on the same plane, i.e., the flange surfaces do not have overlapping portions. By having the flange surfaces on the same plane, when food is placed in the tray-like container and then the opening of the tray-like container is top-sealed, the airtightness of the tray-like container can be ensured, and the freshness of the food placed in the tray-like container can be maintained.
More specifically, the paper layers at the four corners of the flange surface are usually separated, but it is preferable that the flange surface does not have overlapping portions at the four corners. If the flange surface has overlapping portions at the four corners, air tends to enter and exit through the overlapping portions even when top sealing is performed. By not having overlapping portions at the four corners of the flange surface, it is possible to better ensure the airtightness of the tray-shaped container by top sealing the opening of the tray-shaped container after placing food in the tray-shaped container.

In the tray-shaped container of the present invention, the paper layer is preferably bonded with a resin film layer. By bonding the paper layer with a resin film layer, the tray-shaped container can be produced without using an adhesive.
In addition, in the tray-like container of the present invention, the paper layers at the four corners of the flange surface are usually separated, but it is preferable that the paper layers at the four corners are joined by a resin film layer.

The tray-shaped container of the present invention preferably further includes a sub-side surface that is erected from the bottom surface and is not directly connected to the periphery of the opening. By including a sub-side surface that is erected from the bottom surface and is not directly connected to the periphery of the opening, the resin film layer can be evenly and reliably laminated and bonded to the inner surface of the opening side of the paper layer by eliminating corners that are prone to distortion and holes in the resin film layer, and the ease of eating food stored in the tray-shaped container can be improved when the tray-shaped container is used as a lunch container (bowl).

In addition, the paperboard of the tray-shaped container of the present invention is preferably made of a single layer or more, and preferably has eight layers or less, more preferably has seven layers or less, even more preferably has six layers or less, and even more preferably has five layers or less.

Furthermore, the tray-shaped container of the present invention may or may not have an overlapping portion other than the flange surface. If there is an overlapping portion other than the flange surface, the strength of the tray-shaped container is improved. On the other hand, if there is no overlapping portion other than the flange surface, more reliable adhesion between the paper layer and the resin film layer can be achieved.

A tray-shaped container 100 according to a first embodiment will be described below with reference to FIGS.
In the first embodiment, a tray-shaped container is placed on a horizontal surface. The tray-shaped container 100 according to the first embodiment is symmetrical in the front-rear and left-right directions (indicated by "FBLR" in the drawings).
The vertical direction in which gravity acts is referred to as the downward direction (indicated by "D" in the figure), and the opposite direction of the downward direction is referred to as the upward direction (indicated by "U" in the figure). Furthermore, the space side in which the items are stored in the storage space of the container body is referred to as the inside, and the side opposite the inside is referred to as the outside.

Figure 1 is a perspective view of a tray-shaped container according to a first embodiment of the present invention, Figure 2 is a plan view of the tray-shaped container of Figure 1, Figure 3 is a cross-sectional view showing the A-A cross section of Figure 2, and Figure 4 is a plan view of a blank sheet for the container body of Figure 1.

As shown in Fig. 1, the tray-shaped container 100 is a bowl-shaped or rice bowl-shaped paper tray-shaped container. An example of the tray-shaped container 100 is a food packaging container that contains food. However, the tray-shaped container 100 can contain various items other than food.
The tray-shaped container 100 comprises a paper layer 100A forming the container body, and a resin film layer 12 laminated and bonded to the inner surface of the paper layer 100A on the opening 110A side.

The tray-shaped container 100 is a package having an octagonal opening 110A on the upper surface (top surface) and an internal storage space.
The tray-shaped container 100 has an octagonal (polygonal) bottom surface 20, side surfaces 30 standing upright from the bottom surface 20, and a flange surface 40 disposed on the opening periphery 13. The side surfaces 30 have a main side surface 31 standing upright from the bottom surface 20 and directly connected to the opening periphery 13, a first minor side surface 32A standing upright from the bottom surface 20 and not directly connected to the opening periphery 13, and a second minor side surface 32B directly connected to the opening periphery 13 and not standing upright from the bottom surface 20. Folds 14 extend between each side of the bottom surface 20 and the side surfaces 30.
There is no overlapping portion (overlapped piece) on the flange surface 40, and the flange surfaces are on the same plane. The paper layers 100A are joined by the resin film layer 12, and no adhesive or the like is used to join the paper layers 100A together.

The tray-shaped container 100 is formed into a truncated pyramid shape by folding eight sides 30 at creases 14.

As shown in Figures 1 to 3, when the side surfaces 30 are folded and formed into a truncated pyramid shape, the side edges 34, 35 of adjacent side surfaces 30 extending from the bottom surface 20 toward the opening 110A butt against each other to form corners of the truncated pyramid shape. The tray-shaped container 100 is formed into an octagonal truncated pyramid shape having eight corners where the side edges 34, 35 of the eight side surfaces 30 butt against each other. Note that the "corners" referred to here refer to the corners of the side surfaces 30 connecting the upper and lower bases of the truncated pyramid, and do not include the corners between the side surfaces 30 and the bottom surface 20.

A gap 36 is provided at the corner where the side edges 34, 35 are butted against each other.
The gap 36 is formed by separating the side edges 34, 35 from each other, and extends linearly between the bottom surface 20 and the opening 110A.
The gap portion 36 is a portion at the corner that connects the inner side (inside the storage space) and outer side (outside the storage space) of the container body formed by the paper layer 100A, and serves as a passage (flow passage) for air to pass from the inner side to the outer side of the paper layer (container body) 100A during vacuum suction in the manufacturing process of the tray-shaped container 100 described below.
The dimension by which the side edges 34, 35 are separated from each other at the gap 36 is set taking into consideration both the breathability during suction and the moldability of the container body.

The gap 36 in the first embodiment is set to a dimension longer than the dimension of a straight line connecting the bottom surface 20 and the opening 110A. The "straight line" here means a straight line connecting from a corner of the bottom surface 20 to the upper ends of the side edges 34, 35 of the side surface 30 (the intersections of the opening periphery 13 and the side edges 34, 35).
The gap 36 includes a bent portion 37 formed by bending the gap 36 at an intermediate position 100M between the bottom surface 20 and the opening 110A. In the first embodiment, the gap 36 is bent into an L-shape at the bent portion 37. A detailed configuration of the gap 36 will be described later.

In addition, the tray-shaped container 100 has a flange surface 40 that extends from the opening periphery 13 on the upper side (the opening 110A side) of each side surface 30 to the opposite side of the opening 110A. The flange surface 40 is a brim-shaped portion that is provided along the outer periphery of the opening 110A. The side edges of the flange surfaces 40 that extend from adjacent side surfaces 30 are also butted together and spaced apart to form a gap 36. In other words, the gap 36 extends to the flange surface 40.

The detailed configuration of the tray-shaped container 100 according to the first embodiment will be described.
The minor side 32 is formed by a first minor side 32A and a second minor side 32B connected to each other via a fold 38. The fold 38 is a broken line extending parallel to the edge of the bottom surface 20 along the surface of the minor side 32 at an intermediate position 100M. In the minor side 32, the first minor side 32A is folded toward the inside of the tray-shaped container 100 relative to the second minor side 32B via the fold 38.

The first minor side surface 32A has a trapezoidal shape that narrows from the bottom surface 20 toward the intermediate position 100M. The second minor side surface 32B has a trapezoidal shape that widens from the fold 38 corresponding to the upper base of the first minor side surface 32A toward the opening 110A.
That is, the minor side surface 32 is an hourglass-shaped surface portion that is constricted at a middle position 100M when viewed from the side, and both side edges 34 thereof are bent in an L-shape at the middle position 100M.

The main side surface 31 has a side edge 35 bent into a shape that matches the side edge 34 of the sub-side surface 32, and is a hexagonal-shaped side surface 30 having a portion that widens from the bottom surface 20 toward the intermediate position 100M.
Specifically, the side edge 35 of the main side surface 31 is bent along the side edge 34 of the adjacent sub-side surface 32 to form an L-shaped shape. Therefore, a L-shaped gap 36 is formed between the side edge 34 of the sub-side surface 32 and the side edge 35 of the main side surface 31, and this gap 36 is bent into an L-shape at a bend 37 at an intermediate position 100M.

In addition, in the tray-shaped container 100 of this first embodiment, multiple notches are intermittently formed along the folds 14 extending between each side of the bottom surface 20 and the side surfaces 30 (main side surfaces 31 and sub-side surfaces 32).
Additionally, a plurality of cuts are intermittently formed on the minor side 32 along a fold 38 extending between the first minor side 32A and the second minor side 32B.

The multiple cuts formed along the folds 14, 38 form gaps (slits penetrating the container body in the thickness direction) that extend intermittently in a line at the folds 14, 38, and serve as a passageway for air to pass from the inner surface to the outer surface of the container body during suction, as described below.
The dimensions of the cuts along the extension direction of the folds 14, 38 and the number of cuts are set taking into consideration both the breathability during suction and the moldability of the container body.

In addition, if the four minor sides 32 of the tray-shaped container 100 shown in Figures 1 to 3 are regarded as "corner surfaces forming the corners of a quadrangular pyramid," the tray-shaped container 100 can also be viewed as a quadrangular pyramid-shaped container having four main sides (main sides 31) and four corner surfaces (minor sides 32) provided between these sides.
In this way, when the tray-shaped container 100 is considered to have a quadrangular pyramid shape, it can be said to have gaps 36 bent in a dogleg shape along both side edges of the corners (sub-side surfaces 32) that form the corners of the quadrangular pyramid shape. The first sub-side surface 32A of the sub-side surface 32 can also be said to form a surface that is chamfered on the bottom surface 20 side of the corners that form the corners of the quadrangular pyramid shape.

As shown in FIG. 4, the blank sheet 100A' used to form the paper layer (container body) 100A has an octagonal bottom sheet piece 20' and side sheet pieces 30' extending from each side of the bottom sheet piece 20'. In the explanation of FIG. 4, the direction in which the side sheet piece 30' extends from each side of the bottom sheet piece 20' is referred to as the "extension direction", the side of the side sheet piece 30' that faces the bottom sheet piece 20' along the extension direction is referred to as the "inside" of the extension direction, and the opposite side is referred to as the "outside" of the extension direction.

A fold line 14' is provided between the bottom sheet piece 20' and the side sheet piece 30' along the edge of the bottom sheet piece 20'.
In each side sheet piece 30', a parallel fold line 13' is provided along the edge of the bottom sheet piece 20' at the outer edge in the extension direction, and a flange surface sheet piece 40' extends from the fold line 13' toward the outside in the extension direction.

Of each side sheet piece 30', the secondary side sheet piece 32' comprises a first secondary side sheet piece 32A' which has a trapezoidal shape whose width narrows from the edge of the bottom sheet piece 20' toward the outside in the extension direction, and a second secondary side sheet piece 32B' which is connected to the first secondary side sheet piece 32A' and has a trapezoidal shape whose width widens toward the outside in the extension direction toward the opening 110A.
The side edge 34' of the minor side sheet piece 32' is bent in an L-shape.

Of the side sheet pieces 30', the main side sheet piece 31' is hexagonal in shape with a portion that widens from the side of the bottom sheet piece 20' toward the outside in the extension direction. The side edge 35' of the main side sheet piece 31' is bent in a dogleg shape to fit the side edge 34' of the adjacent secondary side sheet piece 32'.

Since the tray-shaped container 100 according to the first embodiment has the configuration described above, it can achieve the following actions and effects (1) to (6).
(1) Since the gap 36 is set to a dimension longer than the dimension of a straight line connecting the bottom surface 20 and the opening 110A, the cross-sectional area of the air flow passage (the dimension of the gap 36 when viewed from the front) can be secured in the gap at the corner. Therefore, the air between the paper layer (container body) 100A and the resin film layer 12 is reliably sucked in, and the resin film layer 12 can be reliably laminated and bonded to the inner surface of the paper layer (container body) 100A.
In addition, since air is more easily sucked in uniformly through the linear gaps 36, the suction load is distributed and the resin film layer 12 is less likely to be damaged. From this point of view, the resin film layer 12 can be reliably laminated and bonded to the inner surface of the paper layer (container body) 100A.
Therefore, it is possible to provide a tray-shaped container 100 in which the resin film layer 12 is appropriately laminated and bonded to the inner surface of the paper layer (container body) 100A.

(2) Since the gap 36 is bent at the bend 37, the dimension of the gap through which air can pass can be increased with a simple configuration compared to a straight gap.
(3) The gaps 36 are bent in a L-shape along the side edges 35, 34 of the main side surface 31 and the sub-side surface 32, respectively, and the structure for ensuring that the dimensions of these pair of gaps 36 are long is simple.

Furthermore, the sub-side surface 32 is formed by the trapezoidal first sub-side surface 32A and the second sub-side surface 32B, and the number of planar portions at the corners of the container body 100A is increased, making the container body 100A less likely to bend and making it easier to ensure the strength of the container body 100A. By increasing the number of planar portions at the corners of the container body 100A, the shape of the inner surface of the storage space of the container body 100A becomes closer to a spherical shape, improving the heat circulation efficiency when the tray-shaped container 100 is heated and cooked in a microwave oven.

(4) Since multiple notches are formed along the folds 14 between each edge of the bottom surface 20 and the side surfaces 30, a linear gap is provided in addition to the gap portion 36, making it easier to pull the resin film sheet described below toward the bottom surface 20, and the resin film layer 12 can be formed more reliably.
(5) Since a plurality of cuts are formed along the fold 38 between the first minor side surface 32A and the second minor side surface 32B on the minor side surface 32, linear gaps can be further increased in addition to the gap portion 36. This makes it easier to draw in a resin film sheet (described later) on the minor side surface 32 side, and allows the resin film layer 12 to be formed more reliably.

(6) The flange surfaces 40 extend from each side surface 30, and the side edges of adjacent flange surfaces 40 are butted together, which reduces the likelihood of partial overlap between the flange surfaces 40 and the resulting step. This makes it easier to mold the upper surface of the flange surface 40 into a flat shape, and therefore the resin film layer 12 can be reliably formed on the upper surface of the flange surface 40 as well.

Next, a tray-shaped container 200 according to a second embodiment will be described with reference to FIGS.
Fig. 5 is a perspective view of a tray-shaped container according to a second embodiment of the present invention, Fig. 6 is a plan view showing the tray-shaped container of Fig. 5, and Fig. 7 is a plan view of a blank sheet for the container body of Fig. 5. The tray-shaped container 200 of Figs. 5 to 7 is different from the tray-shaped container 100 of Figs. 1 to 4 mainly in the side surfaces 50 (41, 42, 43) adjacent to each other at the corners of the container, and the gaps 46 and bent portions 47 provided at the corners, but the other configurations are the same. In the following description, descriptions that overlap with Figs. 1 to 4 will be omitted. The tray-shaped container 200 has less strength than the tray-shaped container 100.

As shown in Figures 5 and 6, the tray-shaped container 200 has a rectangular opening 110B and an octagonal bottom surface 21, and the eight side surfaces 50 extending from each side of the bottom surface 21 are folded to form a truncated pyramid shape.
The tray-shaped container 200 has three types of side surfaces 50 : a first main side surface 41 , a second main side surface 42 , and a sub-side surface 43 .

The first main side surface 41 and the second main side surface 42 butt against each other at their respective side edges 44, 45 in a region from the opening 110B to the intermediate position 200M. Each of the first main side surface 41 and the second main side surface 42 is formed in a hexagonal shape that widens from the bottom surface 21 toward the opening 110B, and the opening periphery 13 forms one side of the opening 110B.
The sub-side surface 43 is disposed between the first main side surface 41 and the second main side surface 42, and is formed in a triangular shape extending from the bottom surface 21 to the intermediate position 200M.

The gap 46 of the tray-shaped container 200 is formed by a side edge 45 of the first major side surface 41 , a side edge 44 of the second major side surface 42 , and a side edge 48 of the minor side surface 43 .
Specifically, the gap 46 is linear along the side edges 44, 45 from the opening 110B to the intermediate position 200M, and branches from the bent portion 47 at the intermediate position 200M toward the bottom surface 21 into two gaps: a gap along the side edge 44 of the second main side surface 42 and one side edge 48 of the sub-side surface 43, and a gap along the side edge 45 of the first main side surface 41 and the other side edge 48 of the sub-side surface 43.

In addition, in the tray-shaped container 200 shown in Figures 5 and 6, the secondary side surface 43 can be said to form a surface portion that is chamfered on the bottom surface 21 side of the four corners of the quadrangular pyramid shape. Also, the gap portion 46 can be said to be a "Y-shaped gap" that branches along the surface portion that is chamfered on the bottom surface 21 side of the four corners of the quadrangular pyramid shape.

As shown in Figure 7, in the blank sheet 200B' used to form the paper layer (container body) 200B, the side sheet pieces 50' extending from each side of the octagonal-shaped bottom sheet piece 21' include a first main side sheet piece 41', a second main side sheet piece 42', and a secondary side sheet piece 43'.
Each of the first main side sheet piece 41' and the second main side sheet piece 42' has a hexagonal shape whose width increases from one side of the bottom sheet piece 21' toward the outside in the extension direction. Each of the first main side sheet piece 41' and the second main side sheet piece 42' has a side edge 45', 44' bent into a dogleg shape.

The minor side sheet piece 43' has a triangular shape extending outward in the extension direction from one side of the bottom sheet piece 21'. More specifically, the minor side sheet piece 43' has an isosceles triangular shape with both side edges 48' having the same length.
The dimension (height of the triangle) along the extension direction of the secondary side sheet piece 43' is set smaller than the dimensions along the extension direction of the first main side sheet piece 41' and the second main side sheet piece 42', so that the gap portion 46 in the paper layer (container body) 200B formed using the blank sheet 200B' branches into two at the intermediate position 200M.

Since the tray-shaped container 200 according to the second embodiment has the configuration described above, it can achieve the following actions and effects.
Since the gap 46 is branched into two, the gap can have a longer dimension for allowing ventilation compared to a straight gap. This makes it easier to ensure the suction properties of the resin film sheet described below, and ensures the formation of the resin film layer 12. In addition, the suction load is easily distributed, making it harder for the resin film sheet described below to tear, and ensuring the formation of the resin film layer 12.
Therefore, the tray-shaped container 200 can be manufactured appropriately.
Furthermore, triangular sub-side surfaces 43 are formed on the bottom surface 21 side at the corners of the container body 200B, and the number of planar portions at the corners of the container body 200B increases, making the container body 200B less likely to bend and making it easier to ensure the strength of the container body 200B. Since the number of planar portions at the corners of the container body 200B increases, the shape of the inner surface of the storage space of the container body 200B becomes closer to a spherical shape, improving the heat circulation efficiency when the tray-shaped container 200 is heated and cooked in a microwave oven.
In addition, the same configuration as the first embodiment provides the same effects as the first embodiment.

The above-described embodiments are merely examples, and are not intended to exclude the application of various modifications or techniques not explicitly stated in these embodiments. Each configuration of the present embodiment can be modified in various ways without departing from the spirit of the invention. In addition, they can be selected and combined as necessary.

For example, the gap is not limited to a bent shape at a bend portion, and may be a curved gap.
The shape of the tray-shaped container is not limited to the bowl-shaped or bowl-shaped (deep dish-shaped) described above, and may be any polygonal truncated pyramid shape, not limited to the octagonal truncated pyramid shape (FIG. 1) or square truncated pyramid shape (FIG. 5). Also, it may be any shape, not limited to each pyramid.
The notches provided at the folds of the tray-shaped container may be omitted.

In addition, as shown in FIGS. 8(a) to 8(d), holding pieces 180, 185, 190, and 195 may be provided extending from one edge of the side surface.
FIG. 8( a ) shows an M-shaped restraining piece 180 that extends from the side edge 35 of the main side surface 31 toward the sub-side surface 32 of the tray-shaped container 100 .
FIG. 8( b ) shows triangular restraining pieces 185 extending from both side edges 48 of the minor side surface 43 of the tray-shaped container 200 toward the first major side surface 41 and the second major side surface 42 .
FIG. 8( c ) shows a tray-shaped container 200 that, in addition to the holding piece 185 of FIG. 8( b ), has a trapezoidal holding piece 190 that extends from the side edge 45 of the first main side surface 41 toward the second main side surface 42 .
FIG. 8( d ) shows triangular restraining pieces 195 extending from both side edges 48 of the minor side surface 43 of the tray-shaped container 200 toward the first major side surface 41 and the second major side surface 42 .
The restraining pieces 180, 185, 190, and 195 can improve the connection strength between adjacent side portions.

<Paper layer>
As mentioned above, the paperboard constituting the paper layer is made of a single layer or more, and preferably has eight layers or less, more preferably has seven layers or less, even more preferably has six layers or less, and even more preferably has five layers or less.
The paper layer is preferably made of multiple layers from the viewpoint of being able to freely adjust the raw material composition, basis weight, papermaking conditions, etc. of each layer.

The paper layer may be a single layer (one layer of paperboard) without any adhesive layer or a multi-layer (multiple layers of paperboard) with adhesive layers.
When the paper layer has a multi-layer structure, the adhesive layer that bonds the paperboards together may be any layer made of a material having adhesive properties, but preferably contains a thermoplastic resin. By using a thermoplastic resin, a laminated paper layer can be easily obtained by coating at least one paperboard with a heated and melted resin and pasting the other paperboard.
Examples of the thermoplastic resin include polyolefin resins, polyester resins, polylactic acid, styrene resins, and acrylic resins. These may be used alone or in combination of two or more. Among these, polyolefin resins are preferred.

Examples of polyolefin resins include polyethylene (LDPE, MDPE, HDPE, LLDPE, etc.), polypropylene, polymethylpentene, etc. These may be used alone or in combination of two or more kinds.
Among these, polyethylene is preferred, LDPE (low density polyethylene) and MDPE (medium density polyethylene) are more preferred, and LDPE is even more preferred.

The adhesive layer may be formed as a single layer of a single resin, or may be formed as a single layer of a mixture of multiple resins, or may be formed as multiple layers made of the same or different types of resins.
The thickness of the adhesive layer is not particularly limited, but from the viewpoint of moldability, it is preferably from 10 μm to 50 μm, more preferably from 10 μm to 30 μm.

The thickness of the paperboard is preferably 200 μm or more and 1000 μm or less, more preferably 250 μm or more and 1000 μm or less, even more preferably 250 μm or more and 700 μm or less, and even more preferably 250 μm or more and 650 μm or less.

The characteristics of the paper layers are explained below, regardless of whether the paper layer is a single layer or a multi-layer structure. Note that if the paper layer is a single layer, the following characteristics refer to the characteristics of the paperboard itself. If the paper layer is a multi-layer structure, the characteristics are the characteristics of each paperboard excluding the adhesive layer, etc.

The thickness of the paper layer is preferably 200 μm or more and 1400 μm or less, more preferably 250 μm or more and 950 μm or less, even more preferably 250 μm or more and 750 μm or less, and even more preferably 260 μm or more and 750 μm or less.

The paper layer is based on a paperboard. The paperboard constituting the paper layer is not particularly limited as long as it is a commonly used paper, and is preferably paper containing plant-derived pulp as a main component, and more preferably paper containing wood pulp as a main component.
Specific examples include kraft paper, fine paper, (white) paperboard, base paper for paper containers, base paper for milk cartons, base paper for cups, liner paper, coated paper, one-sided glossy paper, glassine paper, graphene paper, etc. These may be used alone or in combination of two or more kinds.
Among these, kraft paper, fine paper, (white) paperboard, base paper for paper containers, base paper for cups, and one-sided glossy paper are preferred, and from the standpoint of rigidity, (white) paperboard (high-quality paperboard, special paperboard), base paper for cups, and kraft paper are more preferred.
Examples of the kraft paper include bleached kraft paper, unbleached kraft paper, and one-sided glazed bleached kraft paper. These may be used alone or in combination of two or more kinds.
Among these, bleached kraft paper and one-sided gloss bleached kraft paper are preferred from the standpoint of printability and hygiene.

Alternatively, cardboard consisting of three layers of liner, core and liner may be used as the paperboard, and in particular, microflute cardboard with a small thickness is preferred from the viewpoint of achieving both strength of the paper layer (container body) and moldability.

The basis weight of the paperboard is not particularly limited as long as it is 200 g/ ^m2 or more and 600 g/ ^m2 or less, but is preferably 210 g/m2 or ^more , more preferably 230 g/m2 or ^more , even more preferably 250 g/m2 or ^more , and is preferably 590 g/ ^m2 or less, more preferably 570 g/m2 or ^less , and even more preferably 550 g/m2 or ^less .
In addition, when cardboard is used as the paperboard, the total basis weight of the liner, core and liner is used.
By setting the basis weight of the paperboard to 200 g/m ² or more and 600 g/m ^{2 or} less, it is possible to prevent the resin film layer from breaking even when an impact is applied.
The basis weight of the paperboard is measured in accordance with JIS P8124: 2011. However, when a resin film layer is laminated and bonded to the inner surface of the tray-shaped container, the paper layer is peeled off from the tray-shaped container while taking care not to allow the paper to adhere to the resin film layer, and then the basis weight of the paperboard in the peeled paper layer is measured.

From the viewpoint of molding processability, the density of the paperboard constituting the paper layer is preferably 0.5 g/ ^cm3 or more and 1.2 g/cm3 or ^less , more preferably 0.6 g/cm3 or ^more and 1.0 g/cm3 ^{or less} , even more preferably 0.7 g/ ^cm3 or more and 0.95 g/cm3 or ^less , and even more preferably 0.8 g/cm3 or ^more and 0.95 g/cm3 or ^less .

As described above, the raw material pulp of the paperboard constituting the paper layer is preferably wood pulp, more preferably kraft pulp.
Kraft pulp is classified into hardwood kraft pulp (LKP) and softwood kraft pulp (NKP) based on the difference in raw materials.
In addition, depending on the treatment state, bleached kraft pulp (BKP), unbleached kraft pulp (UKP) and oxygen bleached kraft pulp (OKP) can be mentioned, and from the viewpoint of printability, bleached kraft pulp (BKP) is preferred.
Among these, the raw material pulp is preferably hardwood kraft pulp (LKP) or softwood kraft pulp (NKP), and more preferably a combination of hardwood kraft pulp (LKP) and softwood kraft pulp (NKP). When hardwood kraft pulp (LKP) and softwood kraft pulp (NKP) are used in combination, the mass ratio (LKP/NKP) is not particularly limited as long as it is a ratio used in general paper, and is preferably 1/99 to 99/1, more preferably 20/80 to 99/1, even more preferably 30/70 to 99/1, even more preferably 50/50 to 99/1, and particularly preferably 70/30 to 95/5.
Furthermore, as the hardwood kraft pulp (LKP), hardwood bleached kraft pulp (LBKP) is preferred, and as the softwood kraft pulp (NKP), softwood bleached kraft pulp (NBKP) is preferred.

The disintegration freeness (freeness) of the raw pulp of the paperboard constituting the paper layer, measured in accordance with JIS P8121:2012, is preferably 800 mL or less, more preferably 700 mL or less, even more preferably 600 mL or less, and even more preferably 500 mL or less. The lower limit is preferably 100 mL or more, more preferably 200 mL or more, and even more preferably 300 mL or more. Here, disintegration freeness refers to the Canadian standard freeness (CSF) of the pulp obtained by disintegrating paper after papermaking in accordance with JIS P8220-1:2012, measured in accordance with JIS P8121:2012. The method of beating the pulp to adjust the disintegration freeness can be a known method.

The sizing degree of the paperboard constituting the paper layer is not particularly limited, but it is preferable that the Stockigt sizing degree is 1 second or more in accordance with JIS P8122: 2004. The sizing degree of the paperboard constituting the paper layer can be controlled by the type and content of the internal sizing agent, the type of pulp, smoothing treatment, etc.
Examples of the internal sizing agent include rosin-based, alkyl ketene dimer-based, alkenyl succinic anhydride-based, styrene-acrylic, higher fatty acid-based, petroleum resin-based, etc. These may be used alone or in combination of two or more.
The content of the internal sizing agent is preferably 3 parts by mass or less per 100 parts by mass of the raw pulp of the paperboard constituting the paper layer.

In addition to the internal sizing agent, other known internal additives may be added to the paperboard constituting the paper layer. Examples of internal additives include coagulants (aluminum sulfate), fillers, paper strength agents, retention aids, pH adjusters, drainage improvers, water resistance agents, softeners, antistatic agents, defoamers, slime control agents, dyes and pigments, etc. These may be used alone or in combination of two or more.
Examples of the filler include titanium dioxide, kaolin, talc, calcium carbonate, etc. These may be used alone or in combination of two or more kinds.

In making the paperboard that constitutes the paper layer, a known wet papermaking machine can be appropriately selected and used.
Examples of the paper machine include a Fourdrinier paper machine, a gap former type paper machine, a cylinder paper machine, a short wire paper machine, a twin wire paper machine, etc. These may be used alone or in combination of two or more kinds.
The paper layer formed by the paper machine is preferably conveyed, for example, on a felt and dried in a dryer. A multi-stage cylinder dryer may be used as a pre-dryer before drying in the dryer.

The paperboard obtained as described above may be surface-treated with a calendar to make the thickness and profile uniform. For the calendar treatment, a known calendaring machine can be appropriately selected and used.
The paperboard constituting the paper layer preferably has an Oken smoothness of 5 seconds or more, more preferably 10 seconds or more and 1000 seconds or less. From the viewpoint of printability, the paperboard preferably has a 75° gloss of 5% or more, more preferably 10% or more and 70% or less. From the viewpoint of reducing environmental load, the content of the paper layer in the entire tray-shaped container is preferably 50% by mass or more, more preferably 80% by mass or more.
The material used for the paper layer (container body) is not limited to the above, and various paper materials can be used.

<Resin film layer>
The resin film layer in the tray-shaped container of the present invention is a layer in which the inner surface of the paper layer (container body) is covered (interiorly) with a resin film sheet. The resin film layer is a functional layer that not only maintains the folded state of each side of the paper layer (container body), but also imparts functions such as water resistance and heat resistance to the inner surface of the paper layer (container body).
The resin film sheet used in the resin film layer is made of a sheet material with properties according to the function to be imparted. For example, a plastic sheet with extensibility that takes into account the extension of the resin film sheet when it is attached to the paper layer (container body), water resistance, heat resistance, heat fusion, etc. is used for the resin film sheet.

The resin film layer in the tray-shaped container of the present invention is preferably a resin laminate having extensibility and barrier properties, from the viewpoint of having a role of protecting the surface of the paper layer (container body) from the stored items such as food. The resin laminate includes a barrier layer in the middle layer, and since the layer in contact with the inner surface of the paper layer (container body) needs to be heat-sealed to the paper layer (container body), it is more preferable that the resin laminate has a layer made of a thermoplastic resin.

The barrier layer is not limited to resin and may be metal foil or the like. From the viewpoint of allowing the printed surface of the paper layer to be visible and enhancing the design, however, it is preferable that the barrier layer be made of resin, and more preferably of transparent resin.
The resin constituting the barrier layer is preferably at least one selected from the group consisting of polyamide resins, polyvinyl alcohol, ethylene-vinyl alcohol copolymers (EVOH), and polyvinylidene chloride resins, and more preferably at least one selected from the group consisting of polyamide resins, polyvinyl alcohol, and ethylene-vinyl alcohol copolymers.
The polyamide resin constituting the barrier layer is preferably an aromatic polyamide, more preferably polyamide MXD6.
Examples of resins constituting the layer in contact with the inner surface of the paper layer (container body) of the resin laminate include polyolefin resins such as polyethylene (PE) and polypropylene (PP), aliphatic polyamide resins such as nylon 6, and polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). These may be used alone or in combination of two or more.
The layer facing the inside of the storage space is, for example, ethylene vinyl acetate (EVA), polypropylene (PP) resin, specifically, homopolypropylene, random polypropylene copolymer, or block polypropylene copolymer, and it is particularly preferable to use a random polypropylene copolymer.

Examples of polyamide resins constituting the layer in contact with the inner surface of the paper layer (container body) of the resin laminate include aliphatic polyamide polymers such as nylon 6, nylon 66, nylon 69, nylon 610, nylon 612, nylon 11, nylon 12, etc.; aliphatic polyamide copolymers such as nylon 6-66 (a copolymer of nylon 6 and nylon 66, hereinafter the same), nylon 6-10, nylon 6-12, nylon 6-69, nylon 6-610, nylon 66-69, etc. These may be used alone or in combination of two or more kinds.
Among these, aliphatic polyamide copolymers are preferred, and nylon 6-66, nylon 6-10, or nylon 6-12 is more preferred.

Examples of polyester resins constituting the layer in contact with the inner surface of the paper layer (container body) of the resin laminate include poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene terephthalate/isophthalate), and poly(ethylene glycol/cyclohexane dimethanol/terephthalate). Furthermore, these polymers may contain, as copolymerization components, diols or isophthals such as ethylene glycol, butylene glycol, cyclohexane dimethanol, neopentyl glycol, and pentanediol; dicarboxylic acids such as benzophenone dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, propylene bis(phenyl carboxylic acid), diphenyl oxide dicarboxylic acid, oxalic acid, maleic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and diethylsuccinic acid.

Examples of polyolefin resins constituting the layer in contact with the inner surface of the paper layer (container body) of the resin laminate include polyethylene resins such as linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, and high-density polyethylene; polypropylene resins such as polypropylene; propylene-ethylene copolymers; ethylene-vinyl acetate copolymers; ionomer resins; ethylene-(meth)acrylic acid copolymers; ethylene-(meth)acrylic acid-unsaturated carboxylic acid ester copolymers; etc. These may be used alone or in combination of two or more.
Among these, polyethylene resins are preferred, and linear low-density polyethylene is more preferred.

The resin film sheet used for the resin film layer may have the above-mentioned configuration, or may have a multi-layer configuration in which various types are combined.
From the viewpoint of reducing the environmental load, it is also preferable to use a biodegradable resin such as polylactic acid (PLA), polyglycolic acid (PGA), polybutylene succinate (PBS) as the resin film sheet used for the resin film layer.
The resin film sheets used in the resin film layers may be laminated by a dry lamination method, but are preferably films formed by a co-extrusion method in which the resin film sheets are simultaneously melt-extruded. The resin film sheets A to C used in the examples described later are films formed by a co-extrusion method.

The film thickness of the resin film layer is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more, and is preferably 300 μm or less, more preferably 250 μm or less, and even more preferably 200 μm or less.
By setting the film thickness of the resin film layer to 300 μm or less, the mass of the paper layer can be made greater than the mass of the resin film layer, and the tray-shaped container can be used as a target for applying a paper mark.
Commercially available resin laminates (laminate films) suitable for use in the resin film layer include a PE (polyethylene)/PE (polyethylene)/EVA (ethylene vinyl acetate) three-layer film (product name: Skin Pack, thickness 150 μm) manufactured by Enshu Kasei Co., Ltd., a PP (polypropylene)/EVOH (ethylene-vinyl alcohol copolymer)/special adhesive layer (undisclosed) three-layer film (product name: Diamiron F680, thickness 200 μm) manufactured by Mitsubishi Chemical Corporation, and a PP (polypropylene)/EVOH (ethylene-vinyl alcohol copolymer)/PP (polypropylene) three-layer film (trade name: Diamiron F001, film thickness 40 μm), PP (polypropylene) / PVOH (polyvinyl alcohol) / PP three-layer film (trade name: ECO-B, film thickness 20 μm) manufactured by Futamura Chemical Industry Co., Ltd., NY6 (nylon 6) / EVOH (ethylene-vinyl alcohol copolymer) / NY6 three-layer film (trade name: Heptax HP, film thickness 17 μm) manufactured by Gunze Ltd., NY6 / MXD6 (polyamide MXD6) / NY6 three-layer film (trade name: Embron M, film thickness 15 μm) manufactured by Unitika Ltd., etc. These may be used alone or in combination of two or more kinds.

<Method of manufacturing tray-shaped container>
First, the structure of a molding die 160 used in manufacturing the tray-shaped container 100 using the blank sheet 100A' shown in FIG. 4 will be described with reference to FIGS.
FIG. 9 is a perspective view of a mold 160 used to manufacture the tray-shaped container 100 using the blank sheet 100A'.
The forming die 160 is a metal mold (cavity, female die) for forming the blank sheet 100A' into a pyramidal paper layer (container body) 100A and for laminating and bonding (pressing) the resin film layer 12 to the inner surface of the paper layer (container body) 100A by vacuum suction.

The molding die 160 has a recess 72 recessed into the upper surface side of a base portion 161. The base portion 161 is a base portion that supports the recess 72. The recess 72 is formed in a shape corresponding to the paper layer (container body) 100A (see FIGS. 1 to 3) to be molded, and forms a recess into which the blank sheet 100A' is pressed.
In order to perform suction processing, a plurality of air holes (indicated by reference numeral 78 in FIG. 10 described later) are provided on the inner surface of the recess 72, which communicates between the inside and outside of the recess 72. These air holes are spaced apart from one another and are scattered about.

The recess 72 has a plurality of surface portions 65 on its inner surface that correspond to the surface shape of the paper layer (container body) 100A (see Figures 1 to 3) when the paper layer (container body) 100A (see Figures 1 to 3) is placed on it.
The multiple surface portions 65 specifically include one first surface portion 60 corresponding to the bottom surface 20 (see Figures 1 to 3) of the paper layer (container body) 100A (see Figures 1 to 3) when the paper layer (container body) 100A (see Figures 1 to 3) is placed in the recess 72, and eight second surface portions 71 corresponding to the side surfaces 30 (see Figures 1 to 3) of the paper layer (container body) 100A.

The mold 160 has a flange surface portion 53 extending from the upper edge of the recess 72 toward the outside of the recess 72. The flange surface portion 53 can be divided into eight portions along the outer periphery of the recess 72 corresponding to the eight second surface portions 71, respectively.
Furthermore, a stepped portion 90 is provided so as to protrude along the outer periphery of each flange surface portion 53. The stepped portion 90 forms a step that rises outward relative to the surface portion of each flange surface portion 53.

A groove portion 70 is provided on the inner surface of the recess 72, extending along a linear region corresponding to a linearly extending gap in the paper layer (container body) 100A (see Figures 1 to 3) when the paper layer (container body) 100A is placed in the recess 72.
The groove portion 70 is provided in communication with at least two of the scattered air holes, and forms an air flow passage that extends linearly on the inner surface of the recess 72 during suction processing.
The grooves 70 in this embodiment extend linearly along the boundaries between the multiple surface portions 65 on the inner surface of the recess 72. The boundaries between the multiple surface portions 65 are recessed facing the locations where each edge of the bottom surface 20 contacts the side surface 30 on the paper layer (container body) 100A (see FIGS. 1 to 3 ) and the locations where adjacent side surfaces 30 butt against each other.
The groove portion 70 illustrated here includes a side groove portion 75 extending along the boundary between the second surface portions 71 among the boundaries between the multiple surface portions 65, a bottom groove portion 76 extending along the boundary between the first surface portion 60 and the second surface portion 71, an upper groove portion 73 extending along the boundary between the flange surface portions 53, and a middle groove portion 77 extending along a linear region corresponding to the fold 38.

The side groove portion 75 is provided between the side edges of the second surface portion 71 that correspond to the side surface 30 (see FIGS. 1 to 3) when the paper layer (container body) 100A (see FIGS. 1 to 3) is placed in the recess 72. The bottom groove portion 76 faces between the bottom surface 20 and the side surface 30 of the container body 100A (see FIGS. 1 to 3) when the container body 100A (see FIGS. 1 to 3) is placed in the recess 72.
The upper groove portion 73 faces the gap between the side edges of the flange surface 40 of the paper layer (container body) 100A (see Figures 1 to 3) when the paper layer (container body) 100A is placed in the recess 72.
The middle groove portion 77 faces between the first minor side surface 32A and the second minor side surface 32B of the minor side surface 32 when the paper layer (container body) 100A (see Figures 1 to 3) is placed in the recess 72.

The mold used to manufacture a tray-shaped container 200 using the blank sheet 200B' in Figure 7 has a recess formed in a shape corresponding to the paper layer (container body) 200B (see Figures 5 and 6) to be molded, and differs from the mold 160 in Figure 9 in that it has a groove portion corresponding to the container body, but the other configurations are the same.
The inner surface of the mold recess used to manufacture the tray-shaped container 200 is provided with grooves, such as a side groove portion facing the point where the first main side surface 41, the second main side surface 42 and the sub-side surface 43 are butted together when the paper layer (container body) 200B is placed on it, a bottom groove portion facing the area between the bottom surface 21 and the side surface 50, and an upper groove portion facing the gap between the side edges of the flange surfaces 40.

Next, with reference to FIG. 10, a manufacturing apparatus 150 for manufacturing the tray-shaped container 100 using the molding die 160 will be described.
The manufacturing apparatus 150 includes a first preparation section 201 that folds and arranges a blank sheet 100A' of a paper layer (container body) 100A along the recess 72 of the molding die 160, a second preparation section 202 that arranges a resin film sheet 12A' above the blank sheet 100A' folded in the first preparation section 201, a press section 203 that heats and presses the resin film sheet 12A' arranged in the second preparation section 202 toward the blank sheet 100A' arranged in the first preparation section 201, and a suction section 204 that presses the resin film sheet 12A' pressed in the press section 203 against the blank sheet 100A' by vacuum suction.

The suction section 204 is equipped with a suction device (not shown) that draws in air through the air hole 78 .
The pressing section 203 is equipped with a heating device (not shown) for heating and softening the resin film sheet 12A', and a protruding portion 80 for pressing the resin film sheet 12A'. The protruding portion 80 is a mold (plug, male mold) having a protruding shape corresponding to the recessed portion 72, and is biased downward by a biasing device (not shown). The protruding shape of the protruding portion 80 is set to a smaller dimension than the recessed portion 72.

The method for manufacturing the tray-shaped container 100 by the above-mentioned manufacturing apparatus 150 includes the following steps S1 to S4.
Step S1: A first preparation step of folding and arranging a blank sheet 100A' of a paper layer (container body) 100A along the recess 72 of the forming mold 160. Step S2: A second preparation step of arranging a resin film sheet 12A' above the blank sheet 100A' folded in the first preparation step. Step S3: A pressing step of pressing the resin film sheet 12A' arranged in the second preparation step toward the blank sheet 100A' arranged in the first preparation step while heating it. Step S4: A suction step of pressing the resin film sheet 12A' pressed in the pressing step to the blank sheet 100A' by vacuum suction.

In the above manufacturing device 150, when the resin film sheet 12A' arranged in the second preparation section 202 is heated and pressed toward the blank sheet 100A' arranged in the first preparation section 201, the blank sheet 100A' pressed into the recess 72 has its side surface 30 folded against the bottom surface 20 to form a paper layer (container body) 100A.

In this state, when air is sucked in through the air hole 78 by the suction section 204, the air between the paper layer (container body) 100A and the resin film sheet 12A' is sucked outward through the gap 36 in the paper layer (container body) 100A and the cuts in the folds 14 and 38. This creates a vacuum between the paper layer (container body) 100A and the resin film sheet 12A', and the resin film sheet 12A' is tightly attached to the bottom surface 20, side surface 30, and flange surface 40, forming (vacuum forming) a tray-shaped container 100 in which the resin film layer 12 is laminated and bonded to the inner surface of the paper layer (container body) 100A.

In the tray-shaped container 100 molded as described above, when food or other objects are stored in the storage space of the tray-shaped container 100, the storage space of the paper layer (container body) 100A is replaced with gas, and the opening 110A is closed with a sealing material (film sheet) attached to the flange surface 40.

The molding die 160 is not limited to a structure in which the grooves extend along all the boundaries of the multiple surface portions, but may have a structure in which the grooves extend along some of the boundaries of the multiple surface portions. For example, the upper groove 73 of the flange surface portion 53 may be omitted.
The manufacturing apparatus 150 is not limited to performing only vacuum forming in the above-mentioned suction step (suction means 204), but may also perform vacuum/pressure forming using both vacuum suction and compressed air.

Furthermore, since the molding die 160 has the above-mentioned configuration, it is possible to obtain the following actions and effects (1) to (6).
(1) The grooves 70 are provided in the recesses 72 of the mold 160, communicating with at least two air holes 78, and extend along linear regions corresponding to the linearly extending gaps 36 in the paper layer (container body) 100A, allowing the resin film sheet on the upper surface side of the paper layer (container body) 100A to be sucked in a linear fashion. This distributes the suction load, ensuring uniform adsorption of the resin film sheet.
(2) The forming die 160 is used to manufacture a tray-shaped container 100 having a top surface (top surface) with an opening 110A, a plurality of side surfaces 30 folded at creases 14 along each side of a polygonal bottom surface 20, and a paper layer (container body) 100A formed into a truncated pyramid shape with side edges 34, 35 of adjacent side surfaces 30 butted together to form corners, and a resin film layer 12 formed by pressing a resin film sheet laminated on the inner surface of the paper layer (container body) 100A. The forming die 160 is suitable for the truncated pyramid-shaped tray-shaped container 100 configured as described above, since it can suck the resin film sheet linearly and uniformly along a linear region corresponding to the linearly extending gap portion 36 in the paper layer (container body) 100A.

(3) The grooves 70 extend linearly along the boundaries between the multiple surface portions 65 that correspond to the surface shape of the paper layer (container body) 100A, so that the paper layer (container body) 100A can be sucked uniformly linearly along the contact points between each edge of the bottom surface 20 and the side surface 30 and along the contact points between adjacent side surfaces 30. This distributes the suction load and ensures uniform adsorption of the resin film sheet.
(4) The side grooves 75 allow the resin film sheet on the upper surface side of the paper layer (container body) 100A to be sucked evenly along the gaps 36 at the joints between the side surfaces 30. This makes the adhesiveness of the resin film sheet more reliable.
Furthermore, since the side grooves 75 function as clearances for the side edges 34, 35 at the butting points of the side surfaces 30, a gap can be reliably secured between the side edges 34, 35 of the side surfaces 30 at the butting points. Also, the side surfaces 30 are less likely to be arranged overlapping each other, ensuring the formability of the paper layer (container body) 100A.

(5) The bottom groove portion 76 allows suction along the boundary between the bottom surface 20 and the side surface 30 of the paper layer (container body) 100A, so that the resin film sheet can be reliably drawn into the bottom side of the recess 72.
(6) The upper groove portion 73 ensures a clearance at the point where the flange surfaces 40 are butted together, making it difficult for the flange surfaces 40 to be positioned overlapping each other, thereby ensuring the formability of the paper layer (container body) 100A.
In addition, the stepped portion 90 provided in a protruding manner along the outer periphery of the flange surface portion 53 makes it easier to peel the resin film sheet from the molding die 160 after the tray-shaped container 100 has been molded.

The features of the present invention are explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below.

[Preparation of paper sheet as paperboard substrate for paper layer]
<Production Example 1>
90 parts by mass of bleached hardwood kraft pulp (LBKP) and 10 parts by mass of bleached softwood kraft pulp (NBKP) were mixed and beaten to obtain a pulp slurry.
To 100 parts by mass of the obtained pulp slurry, 0.40 parts by mass (solid content equivalent) of aluminum sulfate (aluminum sulfate) was added to prepare five layers of paper stock for the surface layer, the surface underlayer, the middle layer, the underlayer, and the back layer. The Canadian Standard Freeness (CSF) of this paper stock was 450 mL. Using this paper stock, paper was made using a five-layer twin-wire papermaking machine with the same basis weight for all five layers to obtain paper sheet A1.

<Production Example 2>
Paper sheet A2 was obtained in the same manner as paper sheet A1, except that the surface of the paper sheet was smoothed once with a calendar.

<Production Example 3>
Paper sheet A3 was obtained in the same manner as paper sheet A1, except that a coating liquid (paraffin wax (product name: Sizepine SPW-116H)) manufactured by Arakawa Chemical Industries Co., Ltd. was applied to the surface (film contact surface) of the paper sheet using a bar coater to a dry mass of 10 g/ ^m2 and then dried to form a coating layer.

<Production Example 4>
Paper sheet A4 was obtained in the same manner as paper sheet A1, except that a coating liquid (paraffin wax (product name: Size Pine SPW-116H)) manufactured by Arakawa Chemical Industries Co., Ltd. was applied to the surface (film contact surface) of the paper sheet using a bar coater to a dry mass of 30 g/ ^m2 and then dried to form a coating layer.

<Production Example 5>
Paper sheet A5 was obtained in the same manner as paper sheet A1, except that the surface of the paper sheet was smoothed twice with a calendar.

<Production Example 6>
Paper sheet B was obtained in the same manner as paper sheet A1, except that 70 parts by mass of LBKP and 30 parts by mass of NBKP were mixed and beaten to obtain a pulp slurry.

<Production Example 7>
Paper sheet C was obtained in the same manner as paper sheet A1, except that a pulp slurry using recycled paper pulp with a Canadian Standard Freeness (CSF) of 280 mL was used instead of LBKP and NBKP in only the middle layer of the five paper layers.

[Preparation of resin film sheet constituting resin film layer]
The following three types of resin film sheets were prepared.
(1) Resin film sheet A: Company name: Enshu Kasei Co., Ltd., Product number: Skin Pack, Layer structure: PE (polyethylene) / PE (polyethylene) / EVA (ethylene vinyl acetate) (/paper layer), Thickness: 150 μm
(2) Resin film sheet B: Company name: Mitsubishi Chemical Corporation, Product number: Diamiron F680, Layer structure: PP (polypropylene) / EVOH (ethylene-vinyl alcohol copolymer) / Special adhesive layer (not disclosed) (/ Paper layer), Thickness: 200 μm
(3) Resin film sheet C: Company name: Mitsubishi Chemical Corporation, Product number: Diamiron F001, Layer structure: PP (polypropylene) / EVOH (ethylene-vinyl alcohol copolymer) / PP (polypropylene) (/paper layer), Thickness: 40 μm

[Production of tray-shaped containers]
Example 1
A blank sheet made from the paper sheet A1 obtained in Production Example 1 was sucked from above with a vacuum, the sucked blank sheet was inserted into a mold, and the blank sheet was pressed into the mold by sucking air through the air holes, and folded into a box shape (length of one side of the flange surface 40: about 16.5 cm) as shown in Figure 5 to obtain a paper layer (container body). Next, using a film laminating machine (manufactured by Wakisaka Engineering Co., Ltd., product number: FVT-400), the heater setting temperatures for both the upper and lower heaters were set to 450°C, and three types of resin film sheets A to C were each used and heated for 10 seconds, after which they were vacuum- and air-pressurized adsorbed to the inner surface of the opening side of the paper layer (container body) to laminate and bond them as a resin film layer, to obtain three types of tray-shaped containers 1.

[Physical property measurement and evaluation]
<Measurement of basis weight of paper sheet>
The basis weight of the paper sheet as the paperboard was measured in accordance with JIS P8124:2011. However, when a resin film layer was laminated and bonded to the inner surface of the opening side of the paper layer (container body), the paper layer was peeled off from the resin film layer while being careful not to let the paper adhere to the resin film layer, and then the basis weight of the paperboard (paper sheet) in the peeled paper layer was measured. The measurement results are shown in Table 1.
<Measurement of thickness of paper sheets>
The thickness of the paper sheet as the paperboard was measured in accordance with JIS P 8118:2014. However, when a resin film layer was laminated and bonded to the inner surface of the opening side of the paper layer (container body), the paper layer was peeled off from the resin film layer while being careful not to let the paper adhere to the resin film layer, and then the thickness of the paperboard (paper sheet) at the peeled paper layer was measured. The measurement results are shown in Table 1.
<Density measurement of paper sheets>
The density of the paper sheet as the paperboard was measured in accordance with JIS P 8118:2014. However, when a resin film layer was laminated and bonded to the inner surface of the opening side of the paper layer (container body), the paper layer was peeled off from the resin film layer while being careful not to let the paper adhere to the resin film layer, and then the density of the paperboard (paper sheet) in the peeled paper layer was measured. The measurement results are shown in Table 1.

<Film Breakability>
The resin film sheets A to C adsorbed on the tray-shaped container 1 obtained by vacuum and pressure adsorption were checked for tearing. Furthermore, 300 mL of water was added to the tray-shaped container 1 obtained by vacuum and pressure adsorption, and the container was heated for 300 seconds at 500 W using a microwave oven (company name: SHARP Corporation, product number: RE-T2), after which the resin film sheets A to C of the tray-shaped container 1 were evaluated for tearing according to the following criteria. The evaluation results are shown in Table 1.
<<Evaluation criteria>>
A: In all of the tray-shaped containers 1 obtained using the resin film sheets A to C, no tears were observed in the resin film sheet after heating in a microwave oven.
B: In any of the tray-shaped containers 1 obtained using the resin film sheets A to C, lifting was observed in the resin film sheet after heating in a microwave oven.
C: In any of the tray-shaped containers 1 obtained using the resin film sheets A to C, tears were observed in the resin film sheet after heating in a microwave oven.
D: In any of the tray-shaped containers 1 obtained using the resin film sheets A to C, tears were observed in the resin film sheet before heating in the microwave oven.

<Drop impact resistance>
300 mL of water was poured into the tray-shaped container 1 obtained by vacuum and compressed air adsorption, and the tray-shaped container 1 with the water poured therein was top-sealed with a film having heat sealability, and a drop test was performed in accordance with JIS Z0238:1998 under the following drop test conditions. After the drop test, the top-sealed film was opened, and the container was visually evaluated according to the following criteria as to whether the resin film sheet attached to the tray container 1 had floated, whether the tray-shaped container 1 had warped, and whether there was any water leakage. The evaluation results are shown in Table 1.
The drop impact resistance was evaluated using the tray-shaped container 1 obtained by using the resin film sheet A.
<<Drop test conditions>>
Drop height: 0.50m
Drop surface: SUS plate Drop method: Drop each sample once in the horizontal and vertical directions as specified in JIS Z0238:1998 Number of tests: 5 times (5 identical samples are prepared and each is tested)
<<Evaluation criteria>>
A: None of the tested samples exhibited lifting of the resin film sheet or water leakage.
B: Resin film sheet peeling occurred in 1 to 5 of the tested samples.
C: Distortion of the tray-shaped container was observed in 1 to 5 of the tested samples.
D: The resin film sheet was broken, and water leakage occurred in 1 to 5 of the tested samples.

<Taber stiffness measurement>
Using a Taber stiffness meter (digital Taber stiffness tester manufactured by Toyo Seiki Seisakusho, Ltd.), in accordance with JIS P8125:2000 (Testing method for stiffness of paper and cardboard: Taber stiffness tester method), the Taber stiffness of tray-shaped container 1 obtained using resin film sheet A was measured for three test samples (n=3) in the x direction (approximately UD direction in FIG. 5: direction along the main side surface) of one main side surface and the y direction (FB direction or LR direction in FIG. 5) perpendicular to the x direction, and the average values for each of the x and y directions are shown in Table 1.
In addition, when the size of the tray-shaped container 1 did not allow the test sample to have a predetermined length (70 mm), the measurement was performed with the test sample having a shorter length.

<Adhesive strength (180° peel)>
A test sample having a width of 25 mm in the x direction (approximately UD direction in FIG. 5: direction along the main side) and a length of 70 mm in the y direction (FB direction or LR direction in FIG. 5) perpendicular to the x direction was obtained on one main side of the tray-shaped container 1 obtained using the resin film sheet A. 20 mm of the resin film sheet was peeled off from the obtained test sample of 70 mm length, and a polyester film (A4300 manufactured by Toyobo Co., Ltd.: thickness 75 μm, width 25 mm, length 100 mm) was fixed to the peeled resin film sheet of 20 mm with tape and then bonded to obtain a measurement sample. The obtained measurement sample was pressed by rolling it back and forth twice with a 2 kg roller, and then left to stand for one day in an environment of 23 ° C. and 50% RH in accordance with JIS Z0237:2009, and then left to stand for one day in the same environment (23 ° C. and 50% RH) at atmospheric pressure and room temperature. Under the same environment, the unlaminated portion of the measurement sample (a test sample obtained by cutting out from the tray-shaped container 1) was grasped with an RTC-1210A manufactured by Shimadzu Corporation, and the adhesive strength [N/25 mm] was measured for three measurement samples (n=3) while pulling in the 180° direction at a pulling speed of 300 mm/min, and the average value for each in the y direction was listed in Table 1. Similarly, a test sample having a width of 25 mm in the y direction (FB direction in FIG. 5) and a length of 70 mm in the x direction (approximately UD direction in FIG. 5: direction along the main side surface) perpendicular to the y direction was obtained, and the same measurement was performed, and the average value for each in the x direction was listed in Table 1.
In addition, when the size of the tray-shaped container 1 did not allow the test sample to have a predetermined length (70 mm), the test sample was shortened in length and the measurement was performed.

<Examples 2 to 15 and Comparative Examples 1 to 9>
Tray-shaped containers were obtained in the same manner as in Example 1, except that the manufacturing conditions (tray-shaped container shape, paper layer (paperboard) type, paper layer (paperboard) basis weight, paper layer (paperboard) thickness, paper layer (paperboard) density, single-layer or multi-layer paper layer (paperboard), tray-shaped container depth, and main side taper angle) were changed as shown in Table 1, and evaluation was also performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

The results in Table 1 show that the tray-shaped containers of Examples 1 to 15 prevent the resin film layer from breaking when the resin film layer is laminated and bonded to the inner surface of the opening side of the paper layer, and can also prevent the resin film layer from breaking even when an impact is applied.
In addition, in Examples 11 and 12, the adhesive strength between the paper layer and the resin film layer is changed by changing the surface condition of the paper layer (the surface in contact with the film). Specifically, the adhesive strength is improved by the coating layer (paraffin wax layer) penetrating into the gaps in the paper layer due to the heat during molding, and by the adhesion between the coating layer (paraffin wax layer) and the resin film layer.
Furthermore, it is found that the adhesive strength between the paper layer and the resin film layer decreases when the paper layer surface is smoothed by calendaring, by comparing Example 1, Example 10, and Comparative Example 1. This is presumably because smoothing (calendering) the paper layer reduces the gaps in the paper layer, so that even if the resin film layer melts due to heat, it is difficult for it to enter the gaps in the paper layer.

According to the present invention, a tray-shaped container can be obtained which prevents the resin film layer from breaking when the resin film layer is laminated and bonded to the inner surface of the opening side of the paper layer, and in which the resin film layer will not break even when an impact is applied.
The tray-shaped container of the present invention can be used as a container for food, medicines, medical supplies, electronic components, daily necessities, etc., but is preferably suitable for storing fresh foods such as vegetables, meat, fresh fish, and other fresh foods, as well as processed foods made from these foods, since the items can be stored in a sealed manner.
When the tray-shaped container of the present invention is used as a food container, food can be placed in the tray-shaped container, the inside of the tray-shaped container can be replaced with an inert gas, and the top can be sealed with a film, and the tray-shaped container can be displayed in convenience stores, supermarkets, etc.
Furthermore, the tray-shaped container of the present invention has excellent sealing properties and is suitable for storing, transporting, and displaying food for long periods of time.

12 Resin film layer 12A' Resin film sheet 13 Opening periphery 13' Fold line 14 Fold 14' Fold line 20 Bottom surface 20' Bottom sheet piece 21 Bottom surface 21' Bottom sheet piece 30 Side surface 30' Side sheet piece 31 Main side surface 31' Main side sheet piece 32 Minor side surface 32' Minor side sheet piece 32A First minor side surface 32A' First minor side surface sheet piece 32B Second minor side surface 32B' Second minor side surface sheet piece 34 Side edge 34' Side edge 35 Side edge 35' Side edge 36 Gap portion 37 Bend portion 38 Fold 38' Fold line 40 Flange surface 40' Flange surface sheet piece 41 First major side surface 41' First major side surface sheet piece 42 Second major side surface 42' Second major side surface sheet piece 43 Minor side surface 43' Minor side surface sheet piece 44 Side edge 44' Side edge 45 Side edge 45' Side edge 46 Gap portion 47 Bent portion 48 Side edge 48' Side edge 50 Side surface 50' Side sheet piece 53 Flange surface portion 60 First surface portion 65 Surface portion 70 Groove portion 71 Second surface portion 72 Recess portion 73 Upper groove portion 75 Side groove portion 76 Bottom groove portion 77 Middle groove portion 78 Air hole 80 Convex portion 90 Step portion 100 Tray-shaped container 100A Paper layer (container body)
100A' Blank sheet 100M Intermediate position 110A Opening 110B Opening 150 Manufacturing device 160 Mold 161 Base portion 180 Holding piece 185 Holding piece 190 Holding piece 195 Holding piece 200 Tray-shaped container 200B Paper layer (container body)
200B' Blank sheet 200M Intermediate position 201 First preparation section 202 Second preparation section 203 Press section 204 Suction section (suction means)
A Taper angle B Depth D Down U Up

Claims (7)

A tray-shaped container having an open top and a paper layer based on paperboard and a resin film layer laminated and bonded to the inner surface of the paper layer on the open side,
The tray-shaped container has a bottom surface and a side surface extending upright from the bottom surface,
The side surface includes a main side surface extending from the bottom surface and directly connected to the periphery of the opening, and a sub-side surface extending from the bottom surface,
A side edge of the main side surface and a side edge of the sub-side surface are butted against each other, and a gap is formed by separating the side edges,
The taper angle of the main side surface is 3.5° or more and 10° or less,
The depth of the tray-shaped container is 55 mm or more and 90 mm or less,
The basis weight of the paperboard is 200 g/m ² or more and 600 g/m ² or less,
The Taber stiffness of the paper layer to which the resin film layer is laminated and bonded on the main side surface is 3 mN·m or more and 70 mN·m or less in both a first direction and a second direction perpendicular to the first direction,
The adhesive strength between the paper layer and the resin film layer laminated and bonded to the paper layer on the main side is 0.40 N/25 mm or more in at least one of two directions, a first direction and a second direction perpendicular to the first direction;
A tray-shaped container, wherein the density of the paperboard constituting the paper layer is 0.8 g/cm3 or ^more and 1.2 g/cm3 ^or less. The tray-shaped container according to claim 1, further comprising a flange surface disposed around the periphery of the opening. The tray-like container according to claim 2, wherein the flange surfaces are coplanar. The tray-shaped container according to any one of claims 1 to 3, wherein the paper layer is bonded by the resin film layer. 4. The tray-shaped container according to claim 2 , wherein the paper layers at the four corners of the flange surface are separated, and the paper layers at the four corners are joined by the resin film layer. A tray-shaped container according to any one of claims 1 to 5, in which the secondary side surface is not directly connected to the periphery of the opening. 7. The tray-like container according to claim 1, wherein the paperboard is made of at least one layer and at most eight layers.