JP3027141B2 - Stretchable plastic container structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin container, and more particularly, to an improved structure of a stretchable synthetic resin container in which a bent container wall surface is stretched at the time of use to form a predetermined container shape.

[0002]

2. Description of the Related Art For example, cup-type instant noodles and the like are sold with instant ingredients stored in a bowl or cup-shaped packaging container also serving as tableware. As this container, a molded article of a foamed synthetic resin is frequently used because of its functionality such as light weight and heat insulation.

[0003] Conventional containers of this kind are formed in a final shape as a bowl or a cup, so that there is a problem in that they are very bulky in transfer and storage. In particular, when a display at a sales floor or the like is displayed in a stack of several stages, it cannot be arranged in a large number because the area of the sales floor is limited. If the number of commodities is small or the replenishment is not sufficient, the purchaser's willingness to purchase is reduced due to psychology, which is not preferable for sales promotion.

[0004] In view of the above situation, the present applicant has previously proposed a structure of a stretchable synthetic resin container as Japanese Patent Application Laid-Open No. 9-150833. The packaging container having this structure has a reversing portion bent via a hinge portion on the container wall surface,
At the time of use, the inverted portion is inverted upward and stretched to form a predetermined container shape. In such an extendable container, the height of the wall surface of the container is reduced, which is extremely advantageous in terms of transfer and storage as compared with a normal container formed into a final shape, and also a display in a sales floor or the like. Occasionally more products can be stacked and displayed, which has great merits in sales promotion.

[0005] However, in the structure of the stretchable synthetic resin container, it is required that the strength and rigidity of the wall surface of the container during the extension of the reversing portion during use be assured and sufficient. In particular, when used for instant foods with containers as described above, since hot water is used as it is, there is a strong demand in terms of safety in use.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is directed to a stretchable synthetic resin container having a predetermined container shape formed by extending a wall surface of a container bent during use. It is an object of the present invention to provide a container structure having greater strength and more reliable rigidity when used, particularly when using hot water or the like.

[0007]

That is, the present invention provides:
A predetermined container shape is formed by inverting and inverting the inverted portion upward through a lower hinge portion and an upper hinge portion provided on the upper and lower sides of the inverted portion, which is bent on the container wall surface erected from the bottom portion. A synthetic resin container, wherein the synthetic resin container is formed of a single sheet-like molded article having a synthetic resin foam layer,
A heat-shrinkable film layer is formed on at least a surface of the sheet-like material on the inner surface side of the container.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing one embodiment of the stretchable synthetic resin container of the present invention, FIG. 2 is a central longitudinal sectional view of FIG. 1, FIG. 3 is a sectional view showing an expanded state of FIG. 2, and FIG. FIG. 5 is a schematic cross-sectional view of the main part showing the structure of the present invention, FIG. 6 is a schematic cross-sectional view of the main part at the time of heat shrinkage, and FIG. It is a schematic sectional drawing of the molded article shown.

The extensible synthetic resin container 10 of the embodiment shown in FIGS. 1 to 3 is a packaging container for instant noodles, and is a part of a container wall surface 12 erected from a bottom portion 11 in a circumferential direction. The lower hinge portion 21 having the inverted portion 15 provided on the upper and lower sides thereof as shown in FIG.
In addition, by inverting and extending upward through the upper hinge portion 22, a predetermined container shape 10A is formed. In the illustrated example, the reversing portion 15 of the container wall surface 12 is formed close to the bottom surface portion 11;
As described in 150833, it may be provided at an intermediate portion of the container wall surface. The reference numeral 16 denotes an auxiliary hinge for facilitating the reversal of the reversing unit 15, and 17 denotes a radial rib for facilitating the reversal.

As shown in FIG. 4, the synthetic resin container 10 is formed of a single sheet-like article 30P having a synthetic resin foam layer 31 in consideration of lightness and heat insulation. A heat-shrinkable film layer 35 is formed on at least the surface of the sheet-like material which is the inner surface side 10i of the container. The synthetic resin foam layer 31 has a thickness of 2
A foamed polystyrene resin of ３3 mm is suitably used as this kind of food container. As the heat-shrinkable film layer 35, a known polyethylene film, polypropylene film, polystyrene film, polyester film, or the like is used. The synthetic resin foam layer 31 and the heat-shrinkable film layer 35 are formed as a single sheet 30 that is laminated and integrated. In addition, as the sheet-like material 30, other film layers can be formed as necessary for decoration and printing on the outer surface side of the container.

As shown in FIG. 7, a single sheet-like material 30 shown in FIG.
It is formed into a predetermined container shape by vacuum forming (including plug assist) as shown in FIG. At this time, it is needless to say that the reversing portion 15 is also integrally formed via the hinge portions 21 and 22. The container-shaped molded product 30P molded from the single sheet-like material 30 is cut from the k-line in (A) and separated individually, and then the bottom surface portion 11 is raised as shown in (C) of FIG. And the reversing part 15 is moved upside down by hinges 21 and 22 by a pressing tool (not shown).
Then, it is pushed down into the container and bent to form an extendable container 10. Note that the container 10 shown in FIG.
Upside down.

Next, the operation of the extendable container 10 of the present invention will be described. As described above, in the stretchable container 10 of the present invention, the folded reversing portion 15 is turned upside down and stretched through the lower hinge portion 21 and the upper hinge portion 22 provided above and below the folded reversing portion 15 when used. Container shape 10A. Since the reversing portion 15 formed on the wall portion 12 is an inclined surface that is continuous in the circumferential direction and has a large diameter at the upper portion, after the reversing portion 15 is once turned over, the continuous wall surface is not easily restored. It functions as the unit 12.

Further, in the structure of the present invention, since the heat-shrinkable film layer 35 is formed on at least the surface of the sheet-like material 30 on the inner side 10i of the container, the container has a container shape 10A. When pouring hot water inside,
The heat-shrinkable film 35 causes a shrinkage action by the heat. 5 and 6 are enlarged schematic diagrams of the upper hinge portion 22. FIG. As described above, since this container is formed of a single molded product 30P of the sheet-like material 30, the synthetic resin foam layer 31 in the hinge portion 22 is a portion where the bubbles S are compressed as shown in FIG. 31a. When the heat-shrinkable film 35 is shrunk by hot water as shown by an arrow e in FIG. 6, the compressed portion 31a of the hinge portion 22 is pulled by it, and the compressed air bubbles S in the portion 31a become larger and the synthetic resin of the portion 31b becomes larger. The cross-sectional area of the foam layer 31 increases,
As a result, the strength of the hinge portion 22 increases and the stiffness increases.

The increase in the cross-sectional area of the synthetic resin foam layer 31 due to the shrinkage of the heat-shrinkable film layer 35 occurs in a portion where the air bubbles are compressed during molding. In the embodiment, the same occurs in the auxiliary hinge portion 16 or the radial rib 17. In addition, it is considered that the above phenomenon occurs in the hinge portion 21 on the outer surface side of the container in a certain range. In the embodiment, the heat-shrinkable film layer 35 is provided only on the inner side of the container.
The heat-shrinkable film layer 35 may be provided on both inside and outside of the container.

[0015]

As described above, according to the structure of the present invention, in a stretchable synthetic resin container in which a bent container wall surface is elongated at the time of use to form a predetermined container shape, synthetic resin foaming is performed. Since the heat-shrinkable film layer is formed on at least the inner surface side of the container, the heat-shrinkable film layer is formed on the surface of the sheet-like material at least on the inner side of the container. A container having greater strength and more reliable rigidity when using hot water or the like can be obtained. The structure of the present invention has a great advantage in terms of safety and the like in instant foods with containers in which hot water is used at the time of use.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a stretchable synthetic resin container of the present invention.

FIG. 2 is a central vertical sectional view of FIG.

FIG. 3 is a sectional view showing an extended state of FIG. 2;

FIG. 4 is an enlarged sectional view of a wall portion of FIG. 3;

FIG. 5 is a schematic sectional view of a main part showing the structure of the present invention.

FIG. 6 is a schematic cross-sectional view of a main part during heat shrinkage.

FIG. 7 is a schematic cross-sectional view of a molded product showing a manufacturing process of the stretchable synthetic resin container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stretch-type synthetic resin container 11 Bottom part 12 Container wall surface 15 Inversion part 21 Lower hinge part 22 Upper hinge part 30 Sheet-like material 31 Synthetic resin foam layer 35 Heat shrinkable film layer

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B65D 21/00-21/08 B65D 1/00-1/40 B65D 81/00-81/34

Claims (1)

(57) [Claims] 1. A lower hinge part (21) having an inverted part (15) bent on a container wall (12) erected from a bottom part (11) and provided above and below the inverted part, and an upper part. A synthetic resin container (10) having a predetermined container shape (10A) by being inverted and extended upward through a hinge portion (22), wherein the synthetic resin container is a synthetic resin foam layer (31). And a heat-shrinkable film layer (35) is formed on at least the surface of the sheet-like material (30i) on the inner surface side (10i) of the container. The structure of the stretchable synthetic resin container characterized by the above.