JP7610110B2 - Container and method for manufacturing the container - Google Patents

Description

The present invention relates to a container and a method for manufacturing the container.

Conventionally, containers that can be sealed by heat fusing the container body and the lid have been proposed. For example, Patent Document 1 discloses a microwave container that includes a flange portion formed to extend outward from the opening of the container body, and a heat-sealing portion that is formed in a rib shape around the entire periphery of the upper surface of the flange portion and is heat-sealed to a film-like lid portion (lid material) that closes the opening.

JP 2016-69004 A

However, depending on the function or use of the container, the container body may be made of a material different from that of the lid, making it difficult to control the bonding strength achieved by fusion.

In view of the above, the present invention aims to provide a container and a method for manufacturing the container that allows easy control of the bonding strength between the container body and the lid.

The container of the present invention comprises a container blank having an opening and formed by pulp molding with a flange portion around the periphery of the opening, and a resin fused portion protruding from the flange portion around the edge of the opening, the fused portion including a steam exhaust portion and an opening portion, the steam exhaust portion and the opening portion being formed in an M shape, the upper surface of the steam exhaust portion inclining downwardly so as to be lower than the upper surface of the sharp portion of the opening portion, and the upper surface of the opening portion being formed lower than the upper surface of the fused portion.

The method for manufacturing a container of the present invention is characterized by including the steps of : using an injection molding device in which an injection hole is connected via a gate to a position of the fused portion different from the portion where the fused surface is formed, inserting a container blank formed by pulp molding , having an opening and a flange portion around the periphery of the opening , into a mold of the molding device ; and resin- molding a fused portion that protrudes from the flange portion around the edge of the opening and includes a steam exhaust portion and an opening portion by injection molding.

The present invention provides a container and a method for manufacturing the container that allows easy control of the bonding strength between the container body and the lid.

FIG. 1 is a perspective view of a container according to an embodiment of the present invention. 2A and 2B are diagrams showing the periphery of the flange portion according to an embodiment of the present invention, in which (a) is an enlarged plan view of the corner portion of the container body on the opening portion and steam exhaust portion side, and (b) is a schematic cross-sectional view of the container body of FIG. 2A taken along line IIb-IIb. 1A and 1B are diagrams showing a method for manufacturing a container according to an embodiment of the present invention, in which (a) shows the container body being placed in a molding device, and (b) shows the formation of a fused portion in the container body by injection molding. 2 is a schematic cross-sectional view showing a fused portion in a modified example of an embodiment of the present invention, taken along the line IIb-IIb. FIG. FIG. 13 is a diagram showing a container body in a modified example of the embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described. Fig. 1 is a perspective view of a microwave oven container 10. Fig. 2(a) is an enlarged plan view of a corner of a container body 20 on the side of an opening section 43 and a steam exhaust section 44. The container 10 comprises a container body 20 and a lid section 50 for sealing the container body 20. The container body 20 is formed by a container blank 30 and a fusion section 40 provided on the container blank 30. In this embodiment, the fusion section 40 and the lid section 50 are made of resin. The container blank 30 is formed from a material derived from pulp, and in this embodiment, is produced by pulp molding .

The container blank 30 is formed in a generally rectangular box shape and has an opening 31 at the top. The container blank 30 also has a flange portion 32, which is a brim-like edge portion extending outward from the periphery of the opening 31. The outer peripheral shape of the flange portion 32 is generally rectangular in plan view. The four corners of the flange portion 32 are formed as wide portions 321 that are wider than the other parts of the flange portion 32. The upper surface 322 of the flange portion 32 is formed with a rib-like fusion portion 40 that protrudes upward with a width W2 shorter than the width W1 of the upper surface 322 (see FIG. 2(a)). The fusion portion 40 is formed along the upper surface 322 of the flange portion 32 around the entire edge of the opening 31. Therefore, the fusion portion 40 is arranged in a ring shape so as to surround the outer peripheral edge of the opening 31.

The lid portion 50 is formed in a film shape with approximately the same outer peripheral shape as the flange portion 32. The lid portion 50 can be attached to the fusion portion 40 by thermal fusion after placing the contents in the container blank 30, thereby sealing the opening 31. Figure 1 shows a state in which a part of the lid portion 50 is peeled off from the fusion surface 421 of the fusion portion 40 (the tip portion shown in the IIb-IIb cross-sectional view of Figure 2 (b)).

Inside the container blank 30, a plurality of storage chambers 341 to 343 (34) are formed, which are partitioned by a plurality of partition walls 331, 332. Furthermore, the storage chamber 341 is formed with a larger volume than the storage chambers 342, 343.

2(b) is a schematic cross-sectional view of the container body 20 of FIG. 2(a) taken along line IIb-IIb. The fusion portion 40 provided on the upper surface 322 of the flange portion 32 has a base end 41 fixed to the container blank 30 and a tip end 42 protruding from the base end 41 upward from the container blank 30. The base end 41 and the tip end 42 are connected in a stepped manner. The tip end 42 is provided with a width W3 smaller than that of the base end 41. The tip end 42 is formed long in the vertical direction in cross-sectional view and is formed so as to narrow as it moves from the base end 41 side to the fusion surface 421 side above. The inner side surface 42a and the outer side surface 42b of the tip end 42 of the container blank 30 are inclined. The fusion surface 421 located on the upper surface of the fusion portion 40 is formed as a substantially horizontal flat surface. This fusion surface 421 is provided so as to be fusion-bondable to the resin lid 50.

As shown in FIG. 2(a), the fusion portion 40 in one of the wide portions 321 of the flange portion 32 has an unsealing portion 43 and a steam exhaust portion 44 and is formed in an approximately M-shape. Each unsealing portion 43 is formed on both sides of the steam exhaust portion 44, sharing a portion with the steam exhaust portion 44, and is formed in an approximately V-shape that expands toward the inside of the container body 20 in a plan view. The upper surface of the unsealing portion 43 is also provided as a fusion surface 421. By providing the unsealing portion 43, when the lid portion 50 around the unsealing portion 43 is pulled upward, stress is concentrated on the sharp portion of each unsealing portion 43, and the lid portion 50 and the unsealing portion 43 can be easily peeled off. Therefore, the unsealing portion 43 is formed so that the peel strength is relatively weaker than other fusion portions when the lid portion 50 is opened.

2A, the steam exhaust portion 44 is formed in a substantially V-shape expanding toward the outside of the container body 20. The upper surface of the steam exhaust portion 44 is also provided as a fusion surface 421. The upper surface of the steam exhaust portion 44 is inclined downward so as to be lower than the upper surface of the sharp tip of the unsealing portion 43, and the upper surface of the sharp tip of the unsealing portion 43 is formed lower than the upper surface (fusion surface 421) of the fusion portion 40. In addition, the width of the unsealing portion 43 and the steam exhaust portion 44 is set so as to be narrower than the width of the fusion portion 40. Note that, as shown in FIG. 2A, the width of the M-shaped straight portion including the unsealing portion 43 and the steam exhaust portion 44 is formed narrower than the width of the sharp tip of the unsealing portion 43 and the steam exhaust portion 44. By providing the steam exhaust section 44, when the contents are heated in the microwave, the steam pressure inside the container body 20 rises, and the force that separates the lid section 50 from the container body 20 is concentrated at the sharp tip of the steam exhaust section 44, which is formed in an approximately V-shape, making it easy to peel the lid section 50 and the steam exhaust section 44 apart. In this way, the steam exhaust section 44 is formed so that its peel strength against the steam pressure inside the container body 20 is relatively weaker than other fused parts.

The molding device 60 shown in Figures 3(a) and 3(b) has a mold device (a first mold 61 and a second mold 62), a plasticization section 63, and an injection section 64. The molding device 60 of this embodiment is a pre-plastication type injection molding device. The cavity 621 of the second mold 62 is provided with a recess 621a capable of molding the fusion section 40.

The plasticizing section 63 includes a heating cylinder 631 and a screw 632 rotatably arranged within the heating cylinder 631. Thermoplastic resin, which is the molding material supplied from a supply section 633 on the hopper side and plasticized, is stored within the heating cylinder 631 and can be advanced by the rotation of the screw 632.

The injection section 64 includes an injection cylinder 641, an injection plunger 642 arranged so as to be able to advance and retreat within the injection cylinder 641, and an injection chamber 643, which is a space located at the tip side of the injection plunger 642. Plasticized molding material is supplied to the injection chamber 643 from the plasticizing section 63. The tip of the injection chamber 643 is connected to an injection hole 644 of the nozzle. The injection hole 644 is further connected to a recess 621a of the cavity 621 of the second mold 62. The molding material supplied from the supply section 633 is injected into the recess 621a through the heating cylinder 631, the injection chamber 643, and the injection hole 644.

Next, each step in the manufacturing method of a container will be described. As shown in Fig. 3(a), first, the container blank 30 is inserted into the cavity 611 of the first mold 61. Fig. 3(a) shows the flange portion 32 in the cross-sectional position of IIb-IIb in Fig. 2 (a) after being placed in the first mold 61.

Next, the first mold 61 and the second mold 62 are brought close to each other and clamped, and the flange portion 32 of the container blank 30 is brought close to the cavity 621 of the second mold 62. The flange portion 32 is arranged in contact or sandwiched between the cavity 611 and the cavity 621. The recess 621a provided in the cavity 621 is adjacent to the upper surface 322 of the flange portion 32.

After the first mold 61 and the second mold 62 are clamped together, the molten resin, which is the molding material, is injected from the injection hole 644 to fill the recess 621a (see FIG. 3B). After the resin in the recess 621a has solidified through a cooling period, the first mold 61 and the second mold 62 are opened. In this embodiment, since the container blank 30 is molded using a pulp mold, the upper surface 322 is configured as a rough surface with fine irregularities formed by fibers, etc. However, since the molten resin solidifies in contact with this rough upper surface 322, it is reliably fixed to the upper surface 322. In this way, the fusion portion 40 protruding toward the opening 31 side of the container blank 30 (container body 20) can be provided in the flange portion 32 by resin molding (see FIG. 2B).

As an example of how the container 10 is used, first, food or other contents are stored in each of the storage chambers 341-343 of the container body 20 that are not sealed by the lid portion 50. Then, the lid portion 50 is abutted against the fusion surface 421 of the fusion portion 40 provided on the flange portion 32, and the abutting portion is heated to fuse and join the fusion surface 421 and the lid portion 50. Since the fusion surface 421 is formed in an annular shape, the contents can be stored in the container body 20 that is sealed by the lid portion 50 to form an airtight space. In this way, the container 10 of this embodiment has a portion that comes into contact with the lid portion 50 made of a resin fusion portion 40 (including the opening portion 43 and the steam exhaust portion 44), so that the sealing bonding strength can be increased. In addition, since the fusion portion 40 is formed of resin, the smoothness of the fusion surface 421 can be increased, and the fusion area between the fusion surface 421 and the lid portion 50 can be easily controlled. Therefore, the bonding strength can be controlled more easily than when the fusion part on the container blank 30 side is made of a rough surface made of pulp molding. The fusion part 40 can be made of a pulp-derived material, and can be formed integrally with the container blank 30, for example. However, for areas that require high precision, such as the opening part 43 and the steam exhaust part 44, it is preferable to mold them from resin as described in this embodiment.

When removing the contents, the corners 51 of the lid 50 located on the opening section 43 and steam exhaust section 44 side are pinched and pulled away from the container body 20, so that the lid 50 can be easily peeled away from the sharp tip of the opening section 43. When the contents are heated in a microwave oven, the lid 50 is easily peeled away from the fused section 40 from the sharp tip of the steam exhaust section 44, and the internal space is opened so that steam can be exhausted. In this way, when the corners 51 are pinched to peel off the lid 50 or when the container body 20 is heated in a microwave oven, even if most of the container body 20 is formed from pulp molding, the fused section 40, which is a part that is fused to the lid 50 by secondary processing (secondary molding), is formed from the same resin as the lid 50, so that the peeling part due to the peeling operation of the lid 50 or the escape of steam can be easily controlled.

Next, as a modified example of this embodiment, an example in which a fusion portion 40A is provided on the flange portion 32 instead of the fusion portion 40 will be described with reference to FIG. 4. The fusion portion 40A is formed in a trapezoidal shape in cross section so as to narrow toward the upper fusion surface 421 (i.e., from the base end portion 41A toward the tip end portion 42A). The inner side surface 40a and the outer side surface 40b of the container blank 30 at the tip end 42A are inclined. The fusion portion 40A can be formed with a wider fusion surface 421 than the fusion portion 40. Therefore, the fusion portion 40A can increase the bonding strength of the lid portion 50.

In the above, in this embodiment, a container 10 is described that includes a pulp-made container blank 30 having an opening 31 and a resin-made fusion part 40 that is provided around the edge of the opening 31 and protrudes toward the opening 31. As a result, the container 10 can be sealed with the lid part 50 via the fusion part 40 that is provided in advance on the container blank 30, making it possible to make a container 10 in which the bonding strength between the container body 20 and the lid part 50 can be easily controlled.

In the description of this embodiment, FIG. 3(a) shows the injection hole 644 in the molding device 60 connected to a position in the recess 621a corresponding to the fusion surface 421 of the fusion portion 40, but the injection hole 644 may be configured to be connected via a gate to a position different from the portion where the fusion surface 421 is molded, such as the side wall in the recess 641a (i.e., the inner side surface 42a or the outer side surface 42b of the fusion portion 40). By connecting the gate to a position different from the fusion surface 421, the fusion surface 421 can be easily molded smoothly.

In addition, in this embodiment, the fused portion 40 in FIG. 2(b) and the fused portion 40A in FIG. 4 are described, but the shape and arrangement of the fused portion can be configured arbitrarily. In addition, the container 10 may have a mixture of the fused portion 40 and the fused portion 40A around the edge of the opening 31 of the container blank 30, for example.

In addition, in this embodiment, an example in which the fusion parts 40, 40A are provided by injection molding has been described, but the fusion parts 40, 40A may be provided on the container blank 30 by other methods. For example, the fusion parts 40, 40A prepared in advance may be attached to the container blank 30.

The configuration of this embodiment can be applied to containers of any configuration, not limited to the container 10 (container body 20) shown in Figures 1 to 4. Figure 5 shows a container body 20B, which is mainly different in shape from the container body 20. In the description of the container body 20B, the same components as those of the container body 20 are given the same reference numerals, and the description thereof is omitted or simplified. The container body 20B has a container blank 30B having a circular deep dish shape as a whole, and a fusion portion 40B provided on the upper surface 322 of a circular annular flange portion 32 protruding around the edge of the opening 31 of the container blank 30B. The container blank 30B is also formed of a material derived from pulp. The fusion portion 40B is also formed of a resin material. As shown in the enlarged view of the V-V cross section, the fusion portion 40B has an inner side surface 40c and an outer side surface 40d that are approximately perpendicular to the upper surface 322, and is formed in a generally elongated rectangular shape in cross section. Therefore, the fusion portion 40B is provided so as to protrude in a flat plate shape from the upper surface 322. Even in the container 10B using the container body 20B, the fusion surface 421 is formed in an annular shape, so the contents can be stored in the storage chamber 344, which is sealed by the lid 50 to form an airtight space.

In addition, in this embodiment, an example has been described in which the resin fused portions 40, 40A, 40B are arranged in a ring shape to surround the outer periphery of the opening 31, but one or both of the opening portion 43 and the steam exhaust portion 44 may be formed from resin, and the other portions may be formed from a pulp-derived material other than resin. This allows one or both of the opening portion 43 and the steam exhaust portion 44 to be formed with high precision while reducing the amount of resin in the container body 20, 20B.

The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and essence of the invention, and are included in the scope of the invention and its equivalents described in the claims.

10, 10B Container 20, 20B Container body 30, 30B Container blank 31 Opening 32 Flange portion 40, 40A, 40B Welded portion 40a, 40c Inner side surface 40b, 40d Outer side surface 41, 41A Base end portion 42, 42A Tip portion 42a Inner side surface 42b Outer side surface 43 Opening portion 44 Steam exhaust portion 50 Lid portion 51 Corner portion 60 Molding device 61 First mold 62 Second mold 63 Plasticization portion 64 Injection portion 321 Wide portion 322 Top surface 331 Partition wall 332 Partition wall 341 to 344 Storage chamber 421 Welded surface 611, 621 Cavity 621a Recess 631 Heating cylinder 632 Screw 633 Supply portion 641 Injection cylinder 641a Recess 642 Injection plunger 643 Injection chamber 644 Injection hole W1, W2, W3 Width

Claims (5)

a container blank having an opening and a flange portion on a periphery of the opening, the container blank being formed by pulp molding;
a resin fusion portion provided protruding from the flange portion around the edge of the opening;
Equipped with
The fusion portion includes a steam exhaust portion and an opening portion,
The steam exhaust portion and the opening portion are formed in an M shape,
The upper surface of the steam exhaust portion is inclined downward so as to be lower than the upper surface of the pointed portion of the opening portion,
A container characterized in that an upper surface of the opening portion is formed lower than an upper surface of the fused portion. The container according to claim 1, characterized in that the fusion portion is provided on the upper surface of the flange portion of the container blank in the form of a rib having a width shorter than that of the upper surface. The container according to claim 1 or 2, characterized in that the fused portion has a base end portion that is fixed to the container blank and a tip end portion that is narrower than the base end portion. a container blank having an opening and a flange portion on a periphery of the opening, the container blank being formed by pulp molding;
a resin fusion portion provided protruding from the flange portion around the edge of the opening;
Equipped with
The fusion portion includes a steam exhaust portion and an opening portion,
The steam exhaust portion and the opening portion are formed in an M shape,
The upper surface of the steam exhaust portion is inclined downward so as to be lower than the upper surface of the pointed portion of the opening portion,
The upper surface of the tearing portion is formed lower than the upper surface of the fusion portion,
The fusion portion is provided on an upper surface of the flange portion of the container blank in the form of a rib having a width shorter than that of the upper surface,
The fusion portion has a base end portion fixed to the container blank and a tip end portion narrower than the base end portion, and the base end portion and the tip end portion are connected in a step shape,
A container characterized in that the fused portion is formed so as to narrow toward the fused surface side of the tip portion. using an injection molding device in which an injection hole is connected through a gate to a position of a fusion portion different from a portion where a fusion surface is formed;
a step of inserting a container blank formed by pulp molding, the container blank having an opening and a flange portion on a periphery of the opening, into a mold of the molding device;
A step of resin-molding a fusion portion including a steam exhaust portion and an unsealable portion protruding from the flange portion around the edge portion of the opening by injection molding;
A method for manufacturing a container, comprising:

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