JP2021070489A - Double container - Google Patents

Abstract

To provide a double container which enables efficient peeling of an inner bag from an outer shell immediately after taking-out of a content.SOLUTION: This double container comprises: an outer shell; an outside air introduction hole; and an inner bag. The outer shell can be pressed from the outside, and is configured such that a content stored in the inner bag flows out through a mouth due to this pressing. The outside air introduction hole is provided in a specific region of the bottom side of the outer shell. The bottom side is a side far from the mouth when the double container is bisected in a height direction, and configured such that a check valve fits. By beams of this check valve, air is introduced into a space between the inside of the outer shell and the outside of the inner bag so as to restore the shape of the outer shell after flowing-out of the content. The inner bag is configured so as to be pressed by the air introduced into the space and contracted after reduction of the content.SELECTED DRAWING: Figure 1

Description

The present invention relates to a double container.

A double container (laminated peeling container) having an outer shell and an inner bag and capable of containing the contents in the inner bag is known (for example, Patent Document 1). The outer shell can be pressed from the outside, and the contents contained in the inner bag flow out from the mouth by this pressing. Then, after pressing, air is introduced between the outer shell and the inner bag through a check valve provided on the outer shell to restore the shape of the outer shell and the inner bag gradually withers.

Japanese Unexamined Patent Publication No. 2018-087036

However, in the prior art described in Patent Document 1, since the air introduction hole through which the check valve is inserted is near the mouth portion, air is introduced from the lower side to the upper side of the container immediately after the contents are taken out. It is inefficient.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a double container capable of more efficiently peeling the inner bag from the outer shell immediately after taking out the contents.

According to one aspect of the present invention, the double container is provided with an outer shell, an outside air introduction hole, and an inner bag, and the outer shell can be pressed from the outside and is housed in the inner bag by this pressing. The contents are configured to flow out from the mouth, and the outside air introduction hole is provided in a specific area on the bottom side of the outer shell, where the bottom side is the height direction of the double container. A check valve is fitted on the side far from the mouth when divided into two equal parts, and the check valve allows the outer shell to return to the shape of the outer shell after the contents flow out. Air is introduced into the intermediate space inside the shell and outside the inner bag, and the inner bag is configured to be pressed by the air introduced into the intermediate space and contract when the contents are reduced. Is provided.

Since this double container is provided with a specific area for providing an air introduction hole on the bottom side of the outer shell, it is advantageous that the inner bag can be efficiently peeled off from the outer shell immediately after the contents are taken out. It works.

The perspective view of the double container 1 which concerns on 1st Embodiment is shown. The mode in which the cap 30 is removed from the state of FIG. 1 is shown. The front view and the back view of the double container 1 which concerns on 1st Embodiment are shown. The mode in which the cap 30 is removed from the state of FIG. 3 is shown. The left side view and the right side view of the double container 1 which concerns on 1st Embodiment are shown. The mode in which the cap 30 is removed from the state of FIG. 5 is shown. A plan view and a bottom view of the double container 1 according to the first embodiment are shown. The mode in which the cap 30 is removed from the state of FIG. 7 is shown. It is an end view which shows the internal structure of the double container 1 which concerns on 1st Embodiment. The detailed structure of the check valve 6 is shown. The perspective view of the double container 1 which concerns on 2nd Embodiment is shown. The mode in which the cap 30 is removed from the state of FIG. 11 is shown. The front view and the back view of the double container 1 which concerns on 2nd Embodiment are shown. The mode in which the cap 30 is removed from the state of FIG. 13 is shown. The left side view and the right side view of the double container 1 which concerns on 2nd Embodiment are shown. The mode in which the cap 30 is removed from the state of FIG. 15 is shown. A plan view and a bottom view of the double container 1 according to the second embodiment are shown. The mode in which the cap 30 is removed from the state of FIG. 17 is shown. It is an end view which shows the internal structure of the double container 1 which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The features shown in the embodiments shown below can be combined with each other. In addition, the invention is independently established for each feature.

1. 1. First Embodiment This section describes the configuration of the double container 1 according to the first embodiment. FIG. 1 shows a perspective view of the double container 1 according to the first embodiment. FIG. 2 shows a mode in which the cap 30 is removed from the state of FIG. FIG. 3 shows a front view and a rear view of the double container 1 according to the first embodiment. FIG. 4 shows a mode in which the cap 30 is removed from the state of FIG. FIG. 5 shows a left side view and a right side view of the double container 1 according to the first embodiment. FIG. 6 shows a mode in which the cap 30 is removed from the state of FIG. FIG. 7 shows a plan view and a bottom view of the double container 1 according to the first embodiment. FIG. 8 shows a mode in which the cap 30 is removed from the state of FIG.

1.1 Body 2
The double container 1 is a so-called laminated peeling container. As shown in FIGS. 1 to 8, the double container 1 includes a main body 2 (outer shell 21 and inner bag 22) and an outside air introduction hole 52. The outer shell 21 can be pressed from the outside. By this pressing, the contents contained in the inner bag 22 (accommodation space 26) are configured to flow out from the mouth portion 3. When the contents are reduced, the inner bag 22 is configured to be pressed by the air introduced into the intermediate space 25 through the outside air introduction hole 52 and contract.

The outer shell 21 and the inner bag 22 are subjected to blow molding as a multi-layer parison and are molded in a state of being integrally joined. For example, the inner bag 22 is peeled from the outer shell 21 in advance before use. Then, the contents are filled until the inner bag 22 comes into contact with the outer shell 21. By pushing out the contents, the inner bag 22 contracts smoothly. Alternatively, the inner bag 22 may be left joined to the outer shell 21 so that the inner bag 22 peels off from the outer shell 21 and contracts as the contents are discharged.

As described above, the main body 2 includes an outer shell 21 and an inner bag 22, and the outer shell 21 is formed to be thicker than the inner bag 22 so as to have high resilience.

The outer shell 21 is composed of, for example, low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, an ethylene-propylene copolymer and a mixture thereof. The outer shell 21 has a single layer or a plurality of layers, and it is preferable that at least one of the innermost layer and the outermost layer contains a lubricant. When the outer shell 21 has a single-layer structure, the single layer is the innermost layer and the outermost layer, so that the layer may contain a lubricant. When the outer shell 21 has a two-layer structure, the layer on the inner surface side of the container is the innermost layer, and the layer on the outer surface side of the container is the outermost layer. Therefore, at least one of them may contain a lubricant. When the outer shell 21 is composed of three or more layers, the layer on the innermost surface side of the container is the innermost layer, and the layer on the outermost surface side of the container is the outermost layer.

The innermost layer of the outer shell 21 is a layer in contact with the inner bag 22, and by incorporating a lubricant in the innermost layer of the outer shell 21, the peelability between the outer shell 21 and the inner bag 22 can be improved. On the other hand, the outermost layer of the outer shell 21 is a layer that comes into contact with the mold during blow molding, and the mold releasability can be improved by incorporating a lubricant in the outermost layer of the outer shell 21.

One or both of the innermost layer and the outermost layer of the outer shell 21 can be formed of a random copolymer between propylene and another monomer. Thereby, the shape restoration property, transparency, and heat resistance of the outer shell 21 which is the outer shell can be improved.

The content of the monomer other than propylene in the random copolymer is smaller than 50 mol%, preferably 5 to 35 mol%. As the monomer copolymerized with propylene, ethylene is particularly preferable as long as it improves the impact resistance of the random copolymer as compared with the homopolymer of polypropylene. In the case of a random copolymer of propylene and ethylene, the ethylene content is preferably 5 to 30 mol%. The weight average molecular weight of the random copolymer is preferably 100,000 to 500,000, more preferably 100,000 to 300,000.

The tensile elastic modulus of the random copolymer is preferably 400 to 1600 MPa, preferably 1000 to 1600 MPa. This is because the shape resilience is particularly good when the tensile elastic modulus is in such a range.

If the container is excessively hard, the feeling of use of the container is deteriorated. Therefore, a flexible material such as linear low-density polyethylene may be mixed with the random copolymer to form the outer shell 21. However, the material to be mixed with the random copolymer is preferably mixed so as to be less than 50% by weight with respect to the entire mixture so as not to significantly impair the effective properties of the random copolymer. For example, the outer shell 21 can be made of a material obtained by mixing a random copolymer and a linear low-density polyethylene in a weight ratio of 85:15.

The inner bag 22 includes, for example, an EVOH layer provided on the outer surface side of the container, an inner surface layer provided on the inner surface side of the container of the EVOH layer, and an adhesive layer provided between the EVOH layer and the inner surface layer. By providing the EVOH layer, the gas barrier property and the peelability from the outer shell 21 can be improved.

The EVOH layer is a layer made of an ethylene-vinyl alcohol copolymer (EVOH) resin, and is obtained by hydrolysis of an ethylene-vinyl acetate copolymer. The ethylene content of the EVOH resin is, for example, 25 to 50 mol%, preferably 32 mol% or less from the viewpoint of oxygen barrier properties. The lower limit of the ethylene content is not particularly specified, but 25 mol% or more is preferable because the flexibility of the EVOH layer tends to decrease as the ethylene content decreases. Further, the EVOH layer preferably contains an oxygen absorber. By incorporating an oxygen absorber in the EVOH layer, the oxygen barrier property of the EVOH layer can be further improved.

The melting point of the EVOH resin is preferably higher than the melting point of the random copolymer constituting the outer shell 21. The outside air introduction hole 52 is preferably formed in the outer shell 21 by using a heating type drilling device, but the outside air is introduced into the outer shell 21 by making the melting point of the EVOH resin higher than the melting point of the random copolymer. When forming the hole 52, the hole is prevented from reaching the inner bag 22. From this point of view, the difference between (melting point of EVOH)-(melting point of random copolymer layer) is preferably large, preferably 15 ° C. or higher, and particularly preferably 30 ° C. or higher. This difference in melting point is, for example, 5 to 50 ° C.

The inner layer is a layer that comes into contact with the contents of the double container 1, from polyolefins such as, for example, low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymers and mixtures thereof. It is preferably made of low density polyethylene or linear low density polyethylene. The tensile elastic modulus of the resin constituting the inner surface layer is preferably 50 to 300 MPa, preferably 70 to 200 MPa. This is because the inner layer is particularly flexible when the tensile modulus is in such a range.

The adhesive layer is a layer having a function of adhering the EVOH layer and the inner surface layer. For example, an acid-modified polyolefin in which a carboxyl group is introduced into the above-mentioned polyolefin (eg, maleic anhydride-modified polyethylene) is added, or ethylene acetic acid. It is a vinyl copolymer (EVA). An example of an adhesive layer is a mixture of low density polyethylene or linear low density polyethylene and acid modified polyethylene.

Also, it should be noted that the main body 2 has a flat shape as a whole. With such a configuration, the user can easily press the contents, and the contents can be easily squeezed out, which is an advantageous effect.

1.2 Check valve 6
The outside air introduction hole 52 and the check valve 6 will be described. FIG. 9 is an end view showing the internal configuration of the double container 1 according to the first embodiment. In particular, it should be noted that the region surrounded by the alternate long and short dash line in FIG. 9 has a design feature. FIG. 10 shows the detailed structure of the check valve 6.

As shown in FIG. 9, the outside air introduction hole 52 is provided in the specific region 51 on the bottom side of the outer shell 21. Here, the bottom side is the side far from the mouth 3 when the double container 1 is bisected in the height direction. In particular, it should be noted that in the present embodiment, the specific region 51 is a part of the side surface of the outer shell 21. Specifically, the specific region 51 is located in the recess 5 in the outer shell 21.

The outside air introduction hole 52 is configured to fit the check valve 6. As the check valve 6, for example, a ball valve may be adopted. By this check valve 6, air is introduced into the intermediate space 25 inside the outer shell 21 and outside the inner bag 22 so as to return the shape of the outer shell 21 after the contents flow out. That is, the intermediate space 25 and the external space are communicated with each other by the outside air introduction hole 52.

In this way, the outside air introduction hole 52 is provided in the specific area 51 on the bottom side of the outer shell 21, so that the outside air is directed from above to below through the outside air introduction hole 52 immediately after the contents are taken out. It will be introduced in the space 25. That is, the inner bag 22 can be peeled off from the outer shell 21 more efficiently than in the past.

Subsequently, the check valve 6 fitted in the outside air introduction hole 52 will be described. As shown in FIGS. 10A to 10G, the check valve 6 is a ball valve composed of a cylinder body 60 and a ball 69. The tubular body 60 has a hollow portion 6s provided so as to communicate the external space and the intermediate space 25. The ball 69 is housed so as to be movable in a specific direction in the cavity 6s. Specifically, the diameter of the cavity 6s in the cross section is slightly larger than the diameter of the ball 69 in the corresponding cross section, and the ball 69 can freely move in a specific direction (here, in the vertical direction of the paper surface). It has a possible shape.

The tubular body 60 includes a shaft portion 61 arranged in the outside air introduction hole 52, a locking portion 62 provided on the external space side of the shaft portion 61 and preventing the tubular body 60 from entering the intermediate space 25, and a shaft portion. It has a bulging portion 63 provided on the intermediate space 25 side of the 61 and preventing the tubular body 60 from being pulled out from the outside of the main body 2. The shaft portion 61 has a tapered shape toward the intermediate space 25 side. Then, the tubular body 60 is attached to the main body 2 by bringing the outer peripheral surface of the shaft portion 61 into close contact with the edge of the outside air introduction hole 52.

The surface 66 surrounding the cavity 6s is provided with a stopper portion 65 that locks the ball 69 when the ball 69 moves from the intermediate space 25 side toward the external space side. The stopper portion 65 is formed of an annular protrusion, and when the ball 69 comes into contact with the stopper portion 65, the flow of air through the cavity portion 6s is blocked.

Further, the tip of the tubular body 60 has a flat surface 641, and the flat surface 641 is provided with an opening 64 communicating with the cavity 6s. In addition, it has a plurality of slit portions 642 that radiate from the opening 64.

As shown in FIG. 10F, the check valve 6 is inserted into the outside air introduction hole 52 from the enlarged diameter portion 63 side, and when the locking portion 62 is pushed to a position where it abuts on the outer surface of the outer shell 21, the shaft portion The outer peripheral surface of 61 is held by the outer shell 21 in a state of being in close contact with the edge of the outside air introduction hole 52. When the outer shell 21 is compressed with air in the intermediate space 25, the air in the intermediate space 25 enters the cavity 6s through the opening 64 and pushes up the ball 69 to bring it into contact with the stopper 65. When the ball 69 comes into contact with the stopper portion 65, the flow of air through the cavity portion 6s is blocked.

When the outer shell 21 is further compressed in this state, the pressure in the intermediate space 25 increases, and as a result, the inner bag 22 is compressed and the contents are discharged from the accommodation space 26 inside the inner bag 22. Further, when the compressive force on the outer shell 21 is released, the outer shell 21 tries to be restored by its own elasticity. As the inside of the intermediate space 25 is depressurized with the restoration of the outer shell 21, a force F in the inner direction of the container is applied to the ball 69 as shown in FIG. 10G. As a result, the ball 69 moves toward the bottom of the cavity 6s to be in the state shown in FIG. 10F, and outside air (air) enters the intermediate space 25 through the gap between the ball 69 and the surface 66 and the opening 64. be introduced.

It should be noted that the check valve 6 is a ball valve as described above, which is merely an example, and is not limited to this. Any structure may be used as long as the outside air is introduced into the intermediate space 25 and the backflow is prevented.

1.3 Mouth 3 and cap 30
In the main body 2, the mouth portion 3 is configured so that a cap 30 which is a lid can be attached. Specifically, a male screw portion is provided in the mouth portion 3, and a cap 30 having a female screw is attached to the male screw portion. Here, the cap 30 is configured so that it can be placed upside down with its top surface 31 as a ground plane. Of course, the bottom surface 23 of the double container 1 can be used as a mounting surface, and the double container 1 can be placed upright. In order to stabilize the inversion, if the area of the top surface 31 of the cap 30 is S1 and the area of the mouth 3 is S2 in the double container 1, it is preferable that S1 ≧ 1.5 × S2 is satisfied.

Specifically, if S1 = k × S2, then k = 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2 .4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3 .7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 , 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3 , 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6 , 7.7, 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9 , 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, and the range between any two of the numerical values exemplified here. It may be inside. Since it can be placed in an inverted state, the residual rate can be suppressed even when a viscous substance such as jam, mayonnaise, or ketchup is contained as a content.

By the way, referring to FIG. 9 again, the specific region 51 is configured to have an inclination angle with respect to the opening surface 53 defining the recess 5. Assuming that the inclination angle is θ, it is preferable that the inclination angle θ is 5 degrees or more and 45 degrees or less in the double container 1. Specifically, for example, θ = 5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25, It is 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45 degrees, and any of the numerical values exemplified here. It may be within the range between the two.

By having such an inclination angle θ, the outside air is introduced into the intermediate space 25 so as to go from the upper side to the lower side more smoothly. That is, such a configuration also contributes to efficiently peeling the inner bag 22 from the outer shell 21.

Further, the wall 54 defining the recess 5 is configured to be non-perpendicular to the opening surface 53. Assuming that the angle formed by these is φ, it is preferable that the angle φ is 5 degrees or more and 75 degrees or less in the double container 1. Specifically, for example, φ = 5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25, 26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50, 51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75 degrees It may be within the range between any two of the numerical values exemplified here. Further, it is preferable that φ ≧ θ is satisfied.

By having such an angle φ, when the inner bag 22 is peeled from the outer shell 21, the possibility that the inner bag 22 is caught in the concave portion 5 (convex shape when viewed from the inner bag 22 side) is suppressed. That is, such a configuration also contributes to efficiently peeling the inner bag 22 from the outer shell 21.

Further, the double container 1 further includes a groove 55. Specifically, the groove portion 55 is provided on the bottom side of the outer shell 21 with respect to the specific region 51. By providing such a groove portion 55, when the outside air introduction hole 52 is drilled in the manufacturing process, a fixing jig (not shown) having a convex portion that can be accommodated in the groove portion 55 is used as a positioning reference. be able to. However, the depth of the groove 55 is preferably shallower than the depth of the recess 5. This is because it is good in design that the dents are not conspicuous when the shrink film on which the contents and the like are written is attached to the outside of the double container 1.

2. Second Embodiment In this section, the double container 1 according to the second embodiment will be described. FIG. 11 shows a perspective view of the double container 1 according to the second embodiment. FIG. 12 shows a mode in which the cap 30 is removed from the state of FIG. FIG. 13 shows a front view and a rear view of the double container 1 according to the second embodiment. FIG. 14 shows a mode in which the cap 30 is removed from the state of FIG. FIG. 15 shows a left side view and a right side view of the double container 1 according to the second embodiment. FIG. 16 shows a mode in which the cap 30 is removed from the state of FIG. FIG. 17 shows a plan view and a bottom view of the double container 1 according to the second embodiment. FIG. 18 shows a mode in which the cap 30 is removed from the state of FIG. FIG. 19 is an end view showing the internal configuration of the double container 1 according to the second embodiment. In particular, it should be noted that the region surrounded by the alternate long and short dash line in FIG. 19 has a design feature.

Although the double container 1 according to the second embodiment has the same basic configuration as the double container 1 according to the first embodiment, as shown in FIGS. 11 to 19, the shape of the main body 2 is formed. Please note that is different. In particular, it should be noted that in the second embodiment, the double container 1 has a rounded bottom surface 23 (above the paper surface) and does not stand on its own with the bottom surface 23 as the mounting surface. Therefore, the configuration is based on the premise that the top surface 31 of the cap 30 is the mounting surface.

Further, it should be noted that in the double container 1 according to the second embodiment, the extension surface of the specific region 51 is configured to intersect the pinch-off 231 on the bottom surface 23. With such a configuration, the inner bag 22 tends to wither with the pinch-off 231 as a fulcrum, and the contents are less likely to accumulate on the bottom side, which is an advantageous effect.

Also in the second embodiment, the outside air introduction hole 52 is provided in the specific area 51 on the bottom side of the outer shell 21, so that the outside air flows from above to below through the outside air introduction hole 52 immediately after the contents are taken out. It will be introduced into the intermediate space 25 so as to face. That is, the inner bag 22 can be peeled off from the outer shell 21 more efficiently than in the past.

3. 3. Conclusion As described above, according to the embodiments described so far, it is possible to realize a double container in which the inner bag can be peeled off from the outer shell more efficiently immediately after the contents are taken out.
It may be provided in each of the following aspects.
In the double container, the mouth portion is configured so that a cap can be attached, and the cap is configured so that it can be placed upside down with its top surface as a ground plane.
In the double container, assuming that the area of the top surface of the cap is S1 and the area of the mouth portion is S2, S1 ≧ 1.5 × S2 is satisfied.
In the double container, the specific area is a part of the side surface of the outer shell.
In the double container, the specific region is located in a recess in the outer shell and is configured to have an inclination angle with respect to an opening surface defining the recess.
In the double container, the inclination angle is 5 degrees or more and 45 degrees or less.
In the double container, the wall defining the recess is configured to be non-perpendicular to the opening surface.
In the double container, a groove portion is further provided, and the groove portion is provided on the bottom side of the outer shell with respect to the specific region.
In the double container, the depth of the groove is shallower than the depth of the recess.
In the double container, the check valve is a ball valve.
Of course, this is not the case.

Finally, various embodiments of the present invention have been described, but these are presented as examples and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

1: Double container 2: Main body 3: Mouth part 5: Recessed part 6: Check valve 6s: Cavity part 13: Inner layer 21: Outer shell 22: Inner bag 23: Bottom surface 231: Pinch-off 25: Intermediate space 26: Storage space 30 : Cap 31: Top surface 51: Specific area 52: Outside air introduction hole 53: Opening surface 54: Wall 55: Groove portion 60: Cylindrical body 61: Shaft portion 62: Locking portion 63: Expanded diameter portion 64: Opening portion 65: Stopper Part 66: Surface 69: Ball 641: Flat surface 642: Slit part F: Force θ: Inclined angle φ: Angle

Claims (10)

It ’s a double container,
Equipped with an outer shell, an outside air introduction hole, and an inner bag,
The outer shell can be pressed from the outside, and the contents contained in the inner bag are configured to flow out from the mouth by this pressing.
The outside air introduction hole is
It is provided in a specific area on the bottom side of the outer shell, where the bottom side is the side far from the mouth when the double container is bisected in the height direction.
A check valve is configured to fit, and the check valve allows air to enter the intermediate space inside the outer shell and outside the inner bag so as to return the shape of the outer shell after the contents flow out. Was introduced,
The inner bag is configured to be pressed by the air introduced into the intermediate space and contract when the contents are reduced. In the double container according to claim 1,
The mouth portion is configured so that a cap can be attached.
The cap is configured so that it can be placed upside down with its top surface as a ground plane. In the double container according to claim 2.
Assuming that the area of the top surface of the cap is S1 and the area of the mouth portion is S2,
S1 ≧ 1.5 × S2
Those that meet. In the double container according to any one of claims 1 to 3.
The specific region is a part of the side surface of the outer shell. In the double container according to any one of claims 1 to 4.
The specific area is
Located in a recess in the outer shell
Those configured to have an inclination angle with respect to the opening surface defining the recess. In the double container according to claim 5.
The inclination angle is 5 degrees or more and 45 degrees or less. In the double container according to claim 5 or 6.
The wall defining the recess is configured to be non-perpendicular to the opening surface. In the double container according to any one of claims 5 to 7.
With more grooves
The groove is provided on the bottom side of the outer shell with respect to the specific region. In the double container according to claim 8.
The depth of the groove is shallower than the depth of the recess. In the double container according to any one of claims 1 to 9.
The check valve is a ball valve.

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