JP2008239157A - Plastic double container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double container capable of preventing water from entering a gap between an outer container and inner container after using hot water in a plastic double container. <P>SOLUTION: The outer container 1 and inner container 2 are threadedly engaged with each other by a threaded section provided on both bottom surface sections, and in the process of turning and screwing the inner container 1 to the outer container 2 in a fastening direction, the upper end 12 of an opening of the outer container and a flange 21 of the circumference of an opening of the inner container are force-fitted via a resilient ring-shaped gasket 4 to fix the outer container 1 and inner container 2 in a relative position. A designated gap is arranged between both side walls. A rib section 25 is arranged at a zone where the rib section is in close contact with the gasket 4 at an upper surface side of the inside of the flange. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a plastic double container.

  The plastic double container is composed of an outer container and an inner container, and an air layer can be retained by providing a gap between these containers. As a result, even when hot food such as soup is put inside, the heat retaining property is high and the container can be held with bare hands because it has heat insulation. Moreover, the same effect can be acquired also when cold foods, such as ice cream, are put in the inside.

  As such a double container, for example, it can be firmly coupled with good integrity by the fitting structure of the outer container and the inner container, and has sufficient shape retention strength without increasing the thickness of both containers (patent Document 1), there is a double container for instant food by the present applicant (Patent Document 2).

  Each of these containers has a unique effect. In the case of the double container disclosed in Japanese Utility Model Publication No. 63-6020, in order to prevent water from entering the gap between the outer container and the inner container when the container is washed, etc., at the open end of the outer container and the inner container. It is necessary to completely bond in the fitting. However, in this case, when a label or the like is inserted into the gap between the outer container and the inner container, there is a problem that this replacement becomes difficult.

  In addition, as for Japanese Patent Application No. 2006-307130 by the present applicant, the outer container and the inner container are screwed and locked at the connecting portions provided on both bottom surface portions, and the opening flange portion of the outer container and the inner container is interposed via a gasket. The structure of crimping and fitting is disclosed. If it is this double container, it is excellent in heat retention and heat insulation, and can hold | maintain a label without slack in the clearance gap between an outer container and an inner container. Nevertheless, the outer container and the inner container can be easily separated, and the label can be easily replaced.

Shoko 63-6020 Japanese Patent Application No. 2006-307130

  However, in the double container disclosed in Japanese Patent Application No. 2006-307130, as a result of the experiment using the hot water of the present inventor, after pouring the hot water and eating it, the double container was immersed in water or the like for cleaning. Then, it has been found that there is a possibility that water may enter the gap between the outer container and the inner container.

  The cause can be considered as follows. When hot water is poured into the plastic inner container, the inner container is heated, so the expansion due to heat is large. On the other hand, since the hot water does not directly contact the outer container, the expansion due to heat is relatively small. .

  In this way, the outer container does not expand, but only the inner container is in a expanded state, and the pressure bonding between the outer container and the inner container through the gasket is weakened. It is expected that water will easily enter the gap between the outer container and the inner container.

Therefore, the present inventors have improved the above-mentioned double container, and when hot water is used, the plastic double that can avoid the problem of deterioration of the crimpability through the gasket of the outer container and the inner container. The task was to develop a container.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that the water from the outside to the gap between the outer container and the inner container can be obtained even after using the plastic double container using hot water. An advantageous structure has been found in terms of preventing the intrusion of water.

  About the fixing method of the outer container (1) and the inner container (2) in the double container of this invention, the thread part (11, 22) is each provided in both bottom face parts, and the structure which screws these together is employ | adopted. However, both the containers (1, 2) are not locked and fixed by tightening at the main screw portions (11, 22).

  That is, the gasket (4) in which the outer container opening upper end (12) is inserted into the inner container flange (21) in the process of rotating and screwing the inner container (2) in the tightening direction with respect to the outer container (1). When it comes into contact with and begins to compress it, rotation in the tightening direction gradually becomes difficult. Then, by rotating to the extent that rotation in the tightening direction is prevented, the opening upper end portion (12) of the outer container and the flange portion (21) at the peripheral edge of the inner container opening have an elastic ring-shaped gasket (4). In this state, both containers are fixed.

  By adopting this structure, the hermeticity of the gap (6) between the two containers via the gasket (4) can be improved, and the gap is removed when washed with water or the like after use with hot water. Intrusion of water into the inside of (6) can be prevented.

  Further, in this structure, the heat insulation and heat insulation of the double container can be ensured by forming a gap (6) having a predetermined width between the side walls of the outer container (1) and the inner container (2). In addition, the label (8) can be inserted into the interval (6), and an original My Cup with a favorite picture or photo can be enjoyed.

That is, the first invention of the present application is
A plastic double container including a cup-shaped outer container and an inner container, and having a downwardly recessed flange portion fitted to the outer container opening upper end at the inner container opening periphery,
(1) The outer container and the inner container are screwed together by screw portions provided on both bottom surface portions, and the outer container opening upper end portion and the contents in the process of screwing the inner container into the outer container by rotating in the tightening direction. The flange portion at the peripheral edge of the vessel opening is crimped and fitted through an elastic ring-shaped gasket to prevent rotation in the tightening direction, thereby fixing the relative position of the outer container and the inner container. And
(2) A gap having a predetermined width is formed between each side wall of the outer container and the inner container.
A plastic double container, characterized by
It is.

  Further, in terms of preventing water from entering the gap (6), in particular, the crimping state of the upper end portion (12) of the opening of the outer container, the gasket (4), and the flange portion (21) at the peripheral edge of the inner container opening. Although related, it closely adheres by forming one or several ribs (25) along a circumferential region that is in close contact with the gasket (4) on the upper surface of the flange (21) inner surface of the inner container opening periphery. It has been found that water can be further prevented from entering the gap (6) between the outer container (1) and the inner container (2).

That is, the second invention of the present application is
2. The plastic double container according to claim 1, wherein one or several convex ribs are formed in a circumferential region in close contact with the gasket on the upper surface side of the inner container flange portion inner surface,
It is.

  Next, in the case where the lower end (23) of the side wall of the inner container (2) is in contact with the inner bottom surface of the outer container (1) or has an interval equal to the contact, the inner container ( As for 2), the side wall part is expanded by expansion. In this case, the lower end (23) of the side wall of the inner container contacts the inner bottom surface of the outer container, the inner container (2) is pushed upward, and the outer container (1) and inner container ( It is expected that the pressure bonding of 2) is weakened, and this makes it easier for water to enter the gap (6) between the outer container and the inner container when the double container is washed.

  Similarly, in the threaded portion (22) of the inner container, the position of the male threaded portion (22) on the inner container side may extend downward due to thermal expansion of the inner container. In this case, if the screwed state of the male screw part (22) and the female screw (11) is not able to rotate in the tightening direction or is substantially close to this, the inner container (2) is also pushed upward, It is conceivable that water easily enters the gap (6) of the inner container.

  In addition, it is thought that the deformation | transformation by these thermal expansions advances gradually also by repeated use using hot water.

  Therefore, if a predetermined gap exists between the lower end (23) of the side wall of the inner container and the inner side of the bottom surface of the outer container, the lower end (23) of the side wall of the inner container is not affected by expansion due to thermal deformation. Similarly, if the screwed state in the threaded portion is further rotatable in the tightening direction, the above-described problem does not occur.

That is, the third invention of the present application is
The plastic double container according to claim 1 or 2,
(A) The lower end of the side wall of the inner container has a predetermined gap from the inside of the bottom surface of the outer container,
(B) The threaded state of the threaded portion is a state that can be further rotated in the tightening direction.
Plastic double container,
It is.

  Next, the gasket (4) is inserted into the flange portion (21) at the peripheral edge of the inner container opening, but the outer container (1) and the inner container (2) are separated in work such as replacement of the label (8). In doing so, if the gasket (4) falls from the inner container (2), it is necessary to insert it again, which is complicated. Therefore, it is convenient if a convex portion (24) for preventing the gasket drop is provided on the side surface of the inner surface of the flange portion at the peripheral edge of the inner container opening or near the upper end of the side wall portion.

That is, the fourth invention of the present application is
The plastic double container according to any one of claims 1 to 3, wherein a convex portion for preventing a gasket drop is provided near the upper end of the side wall of the inner container or on the side surface of the inner surface of the flange.
It is.

  Next, if the side wall portion of the outer container (1) and the side wall portion of the inner container (2) have substantially the same taper shape, the label (8) can be inserted into the gap (6) without looseness, In the gap (6) between the two containers, the distance between the side walls of the two containers can be set short, so that the label or the like can be held without sagging.

That is, the fifth invention of the present application is
The double container according to any one of claims 1 to 4, wherein the side wall part of the outer container and the side wall part of the inner container have substantially the same tapered shape,
It is.

  Further, when the lower end (23) of the side wall of the inner container is continuous to the inner side of the bottom surface of the outer container continuously with the side wall of the inner container, the screw portion (11 , 22) etc. are not visible from the outside, are visually superior, and are advantageous because the label can be set to cover the entire side wall of the inner container.

That is, the sixth invention of the present application is
The double container according to any one of claims 1 to 5, wherein the lower end portion of the side wall of the inner container is formed to extend to the vicinity of the inside of the bottom surface of the outer container continuously with the side wall portion of the inner container.
It is.

The plastic double container according to the present invention can prevent water from entering the gap between the outer container and the inner container even after use using hot water, and wets the label inserted in the gap between the two containers. It can be safely held without any problems.

  Hereinafter, examples of the present invention will be described with reference to the drawings. However, the present examples are only one form of the present invention, and are not limited to these examples.

  1 and 2 show an embodiment of a double container according to the present invention. 1 and 2, reference numeral (1) is a plastic outer container whose upper surface is open, and (2) is a plastic inner container whose upper surface is also open. The inner container (2) can be accommodated in the outer container (1), and the inner container (2) is closed by the lid member (3). The outer container (1) and the inner container (2) are formed with a female thread part (11) formed by projecting from the inner center part of the bottom part of the outer container, and a male thread part projecting from the outer center part of the bottom part of the inner container ( 22) screwed together.

  In addition, the aspect of screwing of a thread part is not limited to what was shown to Fig.1 (a). For example, there is also an embodiment shown in FIG. Further, the outer container (1) may have a male thread portion and the inner container (2) may have a female thread portion.

  The side walls of the outer container (1) and the inner container (2) have substantially the same taper shape, and an air layer gap (6) is formed between both side walls.

  Further, details of each part are described. Various plastics can be selected for the outer container (1), and examples thereof include acrylonitrile styrene and polycarbonate.

  When the label (8) is inserted between the outer container (1) and the inner container (2) as described above, the outer container 1 is made of a transparent or translucent material so that the label can be visually recognized from the outside. It is preferable to use it.

In the outer container (1), a female screw part (11) is integrally formed so as to protrude to the inside of the bottom part.
A grounding portion (7) is provided outside the bottom surface portion for the purpose of preventing slipping. Grounding part (7
) Can be used, for example, silicone rubber, ethylene-
There are propylene rubber and nitrile rubber.

  The inner container (2) may come into contact with hot water, but various plastics can be used as long as it is heat resistant. For example, there are heat-resistant polypropylene and polyethylene naphthalate resins. In addition, the inner container (2) may be in-mold molded in addition to a plain color to give a specific design to the outer surface of the side wall.

  The inner container (2) has a flange (21) formed at the upper end of the opening. FIG. 3 shows an enlarged view of the flange portion. In this embodiment, as shown in FIG. 3A, the flange portion is loosely attached near the upper end of the side wall portion of the flange portion to which the ring-shaped gasket (4) is attached. A convex part (24) is provided. By providing such a convex portion, when the gasket (4) is mounted, it can be prevented from dropping. The drop-preventing convex portion may be provided on the side surface of the inner surface of the flange portion as shown in FIG. 3 (b), or may be provided on both sides as shown in FIG. 3 (c). Next, on the upper surface side of the inner surface of the flange portion (21) of the inner container, the rib portion (25) is circular in order to improve the sealing property of the gap (6) between the outer container (1) and the inner container (2). Two are provided along the circumference.

  The flange part (21) of the inner container (2) and the upper open end part (12) of the outer container have a structure in which they are crimped via a gasket (4). FIG. 4 is an enlarged view of this structure after the double container is assembled.

  The opening upper end part (12) of the outer container is adjusted to be thin so that it can be fitted to the flange part (21) of the inner container (12).

  A gasket (4) is attached to the flange portion (21) of the inner container, and the gasket (4) has a flange portion when the upper open end portion (12) of the outer container is fitted into the flange portion (12). It is sandwiched between the inner surface and the upper open end (12) of the outer container and is compressed and deformed by pressure, and is in close contact with both containers.

  The ring-shaped gasket (4) needs to be an elastic material because it has the above-described structure, but the type is not particularly limited, and various materials can be used. Examples thereof include silicone rubber and ethylene-propylene rubber.

  Next, the rib portion (25) of the inner container flange portion (21) is in a state of biting into the gasket (4), thereby enhancing the effect of preventing water from entering the gap (6) from the outside.

  According to the present embodiment, the rib portion (25) has a triangular cross section. However, the rib portion (25) is not limited to this shape, and may be an ellipse or a rectangle. The number of ribs may be one or more. Specifically, about 1 to 5 is preferable.

  When the rib portion (25) is provided, the reason why the water intrusion prevention effect is improved is not clear. However, for example, as shown in FIG. 5, when (a) when the rib portion (25) is provided and (b) when the rib portion (25) is not provided are compared, first, when the rib portion (25) is not provided (FIG. 5). In (b)), the gasket (4) is compressed and is not easily crushed. Therefore, it is considered that sufficient adhesion cannot be maintained between the gasket (4), the upper end of the outer container, and the inner container flange (12). It is done.

  On the other hand, when the rib portion is provided (FIG. 5A), the gasket is easily crushed by the rib portion, and the gasket can be stably compressed. It is considered that a state in which the instrument flange portion (12) is in close contact with the case without the rib portion can be obtained. For these reasons, it is presumed that water can be effectively prevented from entering the gap (6).

  In this embodiment, the gasket has a circular cross section, but is not limited to this, and the cross section may be a square or the like.

  As for the inner surface of the flange portion (21), the size of the gasket (4), and the size of the rib portion (25), the flange portion may have a width corresponding to the diameter of the gasket, and the rib to be used As the size, for example, if the gasket (4) has a circular cross section with a diameter of about 2 mm, the height may be about 0.2 to 0.7 mm.

  The outer container (1) and the inner container (2) are screwed together by a female threaded portion (11) formed by protruding from the inner side of the bottom surface of the outer container and a male threaded portion (22) protruding from the outer side of the bottom surface of the inner container. Has been.

  When fixing the outer container (1) and the inner container (2), by rotating the inner container with respect to the outer container and screwing it in the tightening direction, the female screw part (11) of the outer container and the inner container male screw The part (22) is screwed together.

  In this case, when rotation in the tightening direction is started and this is advanced, the opening upper end portion (12) of the outer container and the gasket (4) mounted in the inner container flange portion begin to approach, and eventually FIG. a) As shown in the upper figure, the open upper end (12) of the outer container reaches the gasket (4) and starts to compress it. Accordingly, rotation in the tightening direction gradually becomes difficult.

  When the rotation in the tightening direction is further advanced, the gasket (4) is further compressed, and as shown in the lower diagram of FIG. 5 (a), the gasket (4) is eventually crushed and deformed so that it cannot be compressed. ) And the inner surface of the flange portion (12) of the inner container opening peripheral edge are pressure-bonded via the deformed gasket (4). In this state, the screw part itself is in a state where it can be further screwed in the tightening direction, but the degree of crimping at the outer container opening upper end part (12) and the inner container flange part (12) is increased, It is difficult to rotate more inner containers in the tightening direction.

  On the other hand, in the loosening direction, the gasket has elasticity and is in close contact with the outer container opening upper end (12) and the inner container flange (12). Unless added, it cannot rotate in the loose direction. Here, fixing of the relative position of the outer container (1) and the inner container (2) is completed.

  FIG. 6 shows the vicinity of the bottom surface of both containers when the outer container (1) and the inner container (2) are fixed. Here, the lower end (23) of the side wall of the inner container reaches the inner side of the bottom of the outer container. As a result, even if the label (8) is inserted inside, it can be held along the side wall, so that the label (8) can be held without sagging to the vicinity of the inside of the bottom surface of the outer container.

  However, as shown in FIG. 6, the side wall lower end (23) has a structure that maintains a predetermined distance d1 from the inside of the bottom surface. As described above, when the side wall lower end portion (23) is in contact with or equal to the inner bottom surface of the outer container, the shape of the inner container expands and changes due to the use of hot water and extends in the vertical direction. In this case, the lower end of the side wall of the inner container contacts the inside of the bottom surface of the outer container and the flange portion (12) of the inner container is pushed upward, and the crimping of the outer container and the inner container via the gasket is weakened. It is estimated that water easily enters the gap between the outer container and the inner container when the double container is washed.

  Therefore, a predetermined gap (d1) is provided in advance between the lower end of the side wall of the inner container and the bottom surface of the outer container. The gap (d1) may be approximately 0.3 to 1.0% or more of the length of the side wall of the inner container, although it depends on the plastic material used.

  In addition, when the threaded portion of the threaded portion cannot be rotated in the tightening direction, the male threaded portion (22) of the inner container expands due to the thermal expansion of the inner container (2). ) Is pushed upward, and it is estimated that water easily enters the gap between the outer container (1) and the inner container (2). For this reason, as shown in FIG. 6, the screwed state at the threaded portion is in a state where it can be further rotated in the tightening direction without considering the crimping at the inner container flange portion (21).

  Further, in such a state, a gap (d2) is generated between the inner side of the bottom surface of the outer container and the lowermost part of the male screw part (22) projecting from the inner container (2).

As for how much the male screw part (22) can be further rotated in the tightening direction,
Although depending on the material of the plastic or the like, since the progress when the male screw portion is rotated becomes a gap (d2), the gap (d2) is approximately 0.3-1. The gap may be about 0% or more.

  Next, the cover material (3) is also assumed in this embodiment. As shown in FIGS. 1 and 2, the lid member (3) has a circular outer shape so as to substantially follow the opening of the inner container (2), and a concentric circle having a smaller radius than the wall surface at the lower part of the wall surface. The convex part has a flange part (31) toward the outer side from the center of the circle. A second gasket (5) is fitted into the flange (31). As shown in FIG. 4, the lid member (3) can be fitted in close contact with the opening of the inner container (2) via the second gasket (5), and the second gasket (5). By using this elasticity, it is possible to form a retaining shape. Further, the lid member (3) may be provided with a knob part (33) for easy opening of the lid.

Also, usually, after storing instant food in the container of the present invention, hot water or the like is poured, and when the inner container is fitted and brought into close contact with the lid material (3), the lid material ( There is a risk of problems such as 3) jumping and flying. Therefore, a small hole (32) is provided for the purpose of removing excess steam.

The side walls of the outer container (1) and the inner container (2) of this container have substantially the same taper, and an air layer gap (6) is formed between both side walls. A label (8) can be inserted into the gap (6) of the air layer. Various insertion methods are possible. For example, the label (8) is brought into close contact with the inner peripheral surface of the barrel of the outer container (1) or the outer peripheral surface of the barrel of the inner container, and in this state, the outer container (1) There is a method in which the inner container (2) is housed in and the label (8) is inserted into the gap between the two containers by screwing. This label (8) can be made of various materials such as paper. For example, various materials such as polyethylene terephthalate having relatively elasticity can be used in addition to paper. You can freely replace your favorite pictures and photos to print.

As the instant food that can be stored and eaten in this container, foods of various shapes and types are possible as long as they can be stored in the inner container (1). In particular, instant food is suitable because hot water can be poured. Specifically, instant noodles, instant wontons and instant soups are possible.

Among the instant foods, particularly instant noodles are instant foods in which the present container can be used effectively. In this case, repackaged instant noodles that are simply packaged are preferred.

Specifically, for example, instant packaging noodles described in Japanese Patent Application No. 2006-254247 by the applicant of the present application are suitable. That is, the technology can restore and eat noodles, soups and ingredients just by adding hot water like commercial instant cup noodles, yet unlike instant cup noodles, packaging It is a packaged instant noodle that is moved from the body to a container and eats. If it is instant noodles for packaging, the cup container is not discarded, and the packaging material to be discarded can be reduced as much as possible.

  As shown in FIG. 7 (a), the packaged instant noodle is a packaged instant noodle in which the instant noodle chunks (9) for refilling are deaerated and wrapped with a soft wrapping material (10), as shown in FIG. 7 (b). As shown in FIG. 7 (c), the double container according to the present invention is covered from the top and turned upside down. Then, as shown in FIG. 9) is taken out and stored in the double container of the present invention, so that hot water can be poured and then eaten.

In particular, when the shape of the instant noodle mass (9) is adjusted to match the tapered shape of the container of the present application and can be held in the middle as shown in FIG. 8 (a), hot water is poured into the container. In this case, the hot water can restore the noodle mass not only from the upper part but also from the lower part of the noodle mass, so that it can be restored quickly. Further, in the state in which the label (8) is inserted, as shown in FIG. 8 (b), the label (8) can be stably held without sagging.

If the plastic double container of the present invention is used, it is possible to prevent water and the like from entering the gap between the outer container and the inner container even after use using hot water or the like. Can be held stably. This allows consumers to insert their favorite pictures and photos, provide original My Cups, and clearly display their contents. Thus, by using this container, it is possible to further develop foods, particularly instant foods such as instant noodles.

It is an end view of the longitudinal cutting part of the double container of an Example. (A) is a longitudinal section end view of the present embodiment, (b) is a longitudinal section end view of a modification. It is a disassembled perspective view of the double container of an Example. It is an enlarged view of the flange part longitudinal section of only an inner container. (A) is a longitudinal cross-sectional view of a present Example, (b), (c) is a longitudinal cross-sectional view of a modification. It is an enlarged view of the longitudinal cross-section of the flange part vicinity of the double container of an Example. It is the longitudinal cross-sectional view which showed the compression state of the gasket. It is the longitudinal cross-sectional view which showed the state of the thread part of the double container of an Example, and the inner container side wall lower end part. It is a perspective view at the time of utilizing a package instant noodle for the double container of an Example. (A) is a perspective view of packaging instant noodles. (B) is the perspective view of the state which started peeling off the opening lid | cover of the said packaging instant noodles. (C) is the perspective view which covered the double container on the packaging instant noodles after opening. (D) is a perspective view of the state which accommodates instant noodle chunks in the double container of an Example. It is a perspective view of the state which stored the instant noodle chunk in the double container of an Example. (A) is a perspective view of the state which stored the instant noodle chunk in the double container. (B) is a perspective view at the time of further inserting a label in (a).

Explanation of symbols

1 Outer container 2 Inner container 3 Lid 4 First gasket (for inner container flange)
5 Second gasket (for lid)
6 Gap 7 Grounding part 8 Insert label 9 Instant noodle mass 10 Packaging container 11 Female thread part 12 Outer container opening upper end part 21 Inner container flange part 22 Male thread part 23 Side wall lower end part 24 Fall prevention convex part 25 Rib part 31 Convex shape Joint (saddle for second gasket)
32 Small hole 33 of the lid material Grip d1 of the lid material A gap d2 between the lower end of the inner container side wall and the inner side of the bottom of the outer container d2 A gap between the lower end of the inner container male screw and the bottom of the outer container

Claims (6)

A plastic double container including a cup-shaped outer container and an inner container, and having a downwardly recessed flange portion fitted to the outer container opening upper end at the inner container opening periphery,
(1) The outer container and the inner container are screwed together by screw portions provided on both bottom surface portions, and the outer container opening upper end portion and the contents in the process of screwing the inner container into the outer container by rotating in the tightening direction. The flange portion at the peripheral edge of the vessel opening is crimped and fitted through an elastic ring-shaped gasket to prevent rotation in the tightening direction, thereby fixing the relative position of the outer container and the inner container. And
(2) A gap having a predetermined width is formed between each side wall of the outer container and the inner container.
A plastic double container characterized by that.
2. The plastic double container according to claim 1, wherein one or several convex ribs are formed in a circumferential region in close contact with the gasket on the upper surface side of the inner container flange portion inner surface.
The plastic double container according to claim 1 or 2,
(A) The lower end of the side wall of the inner container has a predetermined gap from the inside of the bottom surface of the outer container,
(B) The threaded state of the threaded portion is a state that can be further rotated in the tightening direction.
Plastic double container.
The plastic double container according to any one of claims 1 to 3, wherein a convex portion for preventing a gasket drop is provided in the vicinity of the upper end of the side wall of the inner container or on the side of the inner surface of the flange.
The double container according to any one of claims 1 to 4, wherein the side wall part of the outer container and the side wall part of the inner container have substantially the same tapered shape.
The double container according to any one of claims 1 to 5, wherein the lower end portion of the side wall of the inner container is formed so as to extend to the vicinity of the inside of the bottom surface of the outer container continuously with the side wall portion of the inner container.

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