Double container

Abstract

To provide a double container in which occurrence of cracking in an abutting protrusion part is suppressed in a low-temperature fall test even when a container body is formed by biaxially stretching blow-molding a preform constituted by putting an external preform on an internal preform formed by direct blow molding.SOLUTION: A double container comprises a container body. The container body includes an inner bag, and an outer shell arranged so as to cover the inner bag. The inner bag includes a projection part projecting from an opening end of the outer shell. The projection part includes a projection cylinder and an abutting protrusion part. The abutting protrusion part is arranged at a position abutting on the opening end, and is a portion projecting radially outward from the projection cylinder, and further, has an upper wall and a lower wall extending radially outward from the projection part. The upper wall is arranged nearer the opening end of the inner bag than the lower wall, and is provided with a reinforcement part for suppressing rotation of the upper wall with respect to the lower wall.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a dual container. [Background technology]

[0002] Conventionally, a double container having a container body having an outer shell and an inner bag is known. For example, Patent Document 1 discloses a method of manufacturing a container body having an inner bag and an outer shell covering the inner bag by biaxially stretching and blow molding a preform formed by covering an inner preform with an outer preform. In addition, in the container body of Patent Document 1, the inner bag has a protruding portion protruding from the opening end of the outer shell, and the protruding portion is provided with an abutting protrusion that abuts against the opening end of the outer shell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-26868 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors conducted a drop test at low temperatures on a double container having a container body with the same configuration as in Patent Document 1 and found that when the inner preform was direct blow molded, cracks were likely to occur at the contacting convex parts.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and provides a double container in which cracks are suppressed at the contacting convex parts in a low-temperature drop test, even when a preform consisting of an inner preform formed by direct blow molding and an outer preform covered thereon is biaxially stretched blow molded to form a container body. [Means for solving the problem]

[0006] According to the present invention, the following inventions are provided. [1] A double container comprising a container body, the container body comprising an inner bag and an outer shell arranged to cover the inner bag, the inner bag comprising a protrusion protruding from an open end of the outer shell, the protrusion being provided with a protruding tube and a contact protrusion, the contact protrusion being arranged at a position to abut against the open end and being a portion protruding radially outward from the protruding tube, the contact protrusion having an upper wall and a lower wall extending radially outward from the protrusion, the upper wall being arranged closer to the open end of the inner bag than the lower wall, and a reinforcing portion being provided to suppress rotation of the upper wall relative to the lower wall. [2] A double container as described in [1], wherein the abutment convex portion has a plurality of abutment protrusions arranged along the circumferential direction, an intermediate portion is provided between the plurality of abutment protrusions, the intermediate portion is a portion that protrudes from the protruding tube by a smaller amount than the abutment protrusions or does not protrude from the protruding tube, and the reinforcing portion is constituted by the intermediate portion. [3] The double container according to [2], wherein the number of the abutment protrusions is 4 or 8. [4] A double container as described in any one of [1] to [3], wherein the protrusion has an engagement portion for attaching a mouth attachment member at a position closer to the opening end of the inner bag than the abutment convex portion. [5] A double container according to any one of [1] to [4], wherein the container body is a molded body produced by biaxially stretching blow molding a preform formed by covering an outer preform onto an inner preform formed by direct blow molding. Effect of the Invention

[0007] When the inner preform is formed by direct blow molding, unlike when it is formed by injection molding, the contact convex part is not integrated, but has a shape with an upper wall and a lower wall. This shape is also inherited almost as it is by the container body formed by biaxial stretch blow molding, and when the container body is formed by biaxial stretch blow molding of a preform formed by covering an outer preform on an inner preform formed by direct blow molding, the contact convex part has a shape with an upper wall and a lower wall, and it was found that when a force is applied in a direction that rotates the upper wall relative to the lower wall in a low-temperature drop test, the contact convex part is likely to crack. Based on this knowledge, the present inventor found that it is possible to suppress the occurrence of cracks in the contact convex part by providing a reinforcing part that suppresses the rotation of the upper wall relative to the lower wall, and thus completed the present invention. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of a double container 1 according to a first embodiment of the present invention. The dashed and dotted lines in the figure represent the boundary lines at which the curvature of the faces that make up the surface shape changes. The same is true for the other figures. [Diagram 2] FIG. 2 is a perspective view of a container body 2 in FIG. [Diagram 3] FIG. 3 is an exploded perspective view of the vicinity of the mouth portion 5 in FIG. 2. [Figure 4] 4A is a vertical cross-sectional view passing through the center of the mouth portion 5 of the container body 2 of FIG. 2, FIG. 4B is an end view of the cross-section BB in FIG. 4A, and FIG. 4C is an enlarged view of the region C in FIG. 4A. [Diagram 5] FIG. 2 is a perspective view showing a state in which the inner preform 14 and the outer preform 13 are separated. [Figure 6] 1 is a perspective view of a preform 15 formed by covering an inner preform 14 with an outer preform 13. FIG. [Figure 7] FIG. 4 is an exploded perspective view corresponding to FIG. 3, of a double container 1 according to a second embodiment of the present invention. [Figure 8] 8 is an end view corresponding to FIG. 4B of the double container 1 of FIG. 7. [Figure 9]FIG. 11 is a perspective view of an inner preform 14 used in a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described. Various features shown in the following embodiments can be combined with each other. Also, each feature can be an invention independently.

[0010] 1. First embodiment 1-1. Structure of double container 1 <Basic configuration> As shown in FIG. 1, a double container 1 according to a first embodiment of the present invention comprises a container body 2 and a spout mounting member 8. The double container 1 has a container body 2 and a spout mounting member 8. The spout mounting member 8 is made of a material such as aluminum.

[0011] As shown in Figs. 2 and 3, the container body 2 has a mouth 5, a trunk 6, and a bottom 7. The mouth 5 is a tubular (preferably cylindrical) portion having an open end 5c. The open end 5c is the open end of the container body 2 and also the open end of the inner bag 4. The mouth 5 has an engagement portion 4m to which a mouth attachment member 8 can be attached. In this embodiment, the mouth attachment member 8 is a cap 8a, but may be a pump. The mouth 5 is provided with a flange 5b. The flange 5b can be used to support the mouth 5 when the mouth attachment member 8 is attached to the mouth 5.

[0012] The body 6 is disposed adjacent to the mouth 5 on the side farther from the open end 5c than the mouth 5. The body 6 has a larger outer diameter (in this specification, "outer diameter" means a circular equivalent diameter when the cross section is not circular) than the mouth 5. The body 6 is cylindrical, and the bottom 7 is provided at the lower end of the body 6 and closes the lower end of the body 6. The body 6 has a shoulder 6b whose outer diameter increases with increasing distance from the mouth 5. The body 6 also has a body main body 6c on the bottom 7 side of the shoulder 6b. The body main body 6c has a shape in which the outer diameter is approximately constant toward the bottom 7, or a shape in which the diameter decreases toward the bottom 7, for example.

[0013] 3, the container body 2 includes an inner bag 4 and an outer shell 3 arranged to cover the inner bag 4. The inner bag 4 has an inner bag body 4d other than the protruding portion 4c housed within the outer shell 3. In the following description, the portions of the inner bag 4 that correspond to the mouth 5, body 6, and bottom 7 of the container body 2 will be referred to as the mouth 5, body 6, and bottom 7 of the inner bag 4, respectively. The same applies to the outer shell 3.

[0014] <Detailed structure of outer shell 3 and inner bag 4> 2 to 4, the inner bag 4 has a protruding portion 4c protruding from the open end 3a of the outer shell 3. The protruding portion 4c has a protruding tube 4c1, an engaging protruding portion 4c2, an annular protruding portion 4c5, and a contacting protruding portion 4v.

[0015] The annular protrusion 4c5 engages with the mouth attachment member 8 in the axial direction. The engaging protrusion 4c2 engages with the mouth attachment member 8 in the circumferential direction. The engaging protrusion 4c2 and the annular protrusion 4c5 form an engaging portion 4m. The engaging portion 4m is disposed at a position closer to the open end 5c of the inner bag 4 than the abutting protrusion 4v. In this specification, the "axial direction" refers to the direction in which the central axis C of the mouth 5 extends, in other words, the direction in which the inner bag 4 is pulled out from the container body 2. The "circumferential direction" refers to the direction in which the mouth 5 rotates around the central axis C of the mouth 5, in other words, the direction in which the inner bag 4 is rotated relative to the outer shell 3 at the mouth 5.

[0016] The engaging protrusions 4c2 are preferably provided at a plurality of locations (eight locations in this embodiment) spaced apart in the circumferential direction. The engaging protrusions 4c2 are disposed on the annular protrusion 4c5 and are provided so as to protrude radially outward from the annular protrusion 4c5. The annular protrusion 4c5 and the engaging protrusions 4c2 are provided with a tapered surface 4c8 on the upper surface. This makes it easier for the annular protrusion (not shown) provided on the mouth mounting member 8 to climb over the annular protrusion 4c5 and the engaging protrusions 4c2.

[0017] The contact protrusion 4v is disposed at a position where it contacts the open end 3a and is a portion that protrudes radially outward from the protruding tube 4c1. The contact protrusion 4v contacts the open end 3a, thereby preventing the inner bag 4 from falling off into the outer shell 3. The details of the contact protrusion 4v will be described later.

[0018] As shown in Fig. 3, a cam protrusion 4g is provided on the outer peripheral surface of the inner bag body 4d. The lower surface of the cam protrusion 4g is inclined so as to approach the opening end 5c as it progresses counterclockwise when viewed from the opening end 5c side of the mouth portion 5. In addition, a cam rail 3l is provided on the inner peripheral surface of the outer shell 3.

[0019] Before the inner bag 4 is pulled out from the container body 2, the lower surface of the cam protrusion 4g abuts against the upper surface of the cam rail 3l. The cam protrusion 4g and the cam rail 3l form a cam mechanism 31. When the inner bag 4 is rotated counterclockwise, the inner bag 4 moves in a direction to come out of the container body 2 due to the action of the cam mechanism 31. At this time, the inner bag 4 is twisted and reduced in diameter.

[0020] <Removing inner bag 4> The mouth attachment member 8 is preferably configured to be attachable to the mouth 5 of the container body 2 in a plug-type manner, and by placing the mouth attachment member 8 over the mouth 5 and pressing the mouth attachment member 8 in the direction of the bottom 7, the mouth attachment member 8 can be engaged with and attached to the mouth 5.

[0021] The mouth attachment member 8 is engaged with the mouth 5 of the inner bag 4 in the circumferential and axial directions, and is configured so that the inner bag 4 rotates relative to the outer shell 3 as the mouth attachment member 8 rotates. The inner bag 4 is configured to move in a direction coming out of the container body 2 as the inner bag 4 rotates due to the action of a cam mechanism 31 provided between the inner bag 4 and the outer shell 3.

[0022] According to this configuration, by rotating the mouth attachment member 8, the inner bag 4 can be moved in a direction that allows it to be removed from the container body 2 while twisting, and then by pulling the mouth attachment member 8, the inner bag 4 can be pulled out of the container body 2. Note that the inner bag 4 may be separated from the container body 2 by pulling it in the axial direction without twisting it. Even in this case, according to the configuration of the present invention, the force required to separate the inner bag 4 is reduced.

[0023] <Details of the contact protrusion 4v> As described later, the container body 2 is preferably a molded body produced by biaxially stretching and blow molding a preform 15 (shown in Figs. 5 and 6) formed by covering an outer preform 13 on an inner preform 14 formed by direct blow molding. When the inner preform 14 is formed by direct blow molding, the contact protrusion 4v is not integrated unlike when it is formed by injection molding, and the upper wall 4v1 and the lower wall 4v2 are connected at the tip 4v3 as shown in Fig. 4C. The upper wall 4v1 is disposed closer to the opening end 5c of the inner bag 4 than the lower wall 4v2. When the thickness of the base of the contact protrusion 4v is greater than the total thickness of the upper wall 4v1 and the lower wall 4v2, a gap 4v4 is formed between the upper wall 4v1 and the lower wall 4v2. The gap 4v4 gradually narrows toward the tip 4v3.

[0024] The low-temperature drop test of the double container 1 is performed with the mouth attachment member 8 attached to the engagement portion 4m, and when the body 6 of the double container 1 hits the ground, a rotational force is applied to the mouth attachment member 8, and the rotational force is applied to the contact protrusion 4v via the engagement portion 4m. If the contact protrusion 4v is formed integrally, the contact protrusion 4v is unlikely to crack due to the rotational force generated during the drop, but if the contact protrusion 4v has an upper wall 4v1 and a lower wall 4v2, the rotational force generated during the drop applies a force in a direction that rotates the upper wall 4v1 relative to the lower wall 4v2, which can easily cause a problem of cracking the contact protrusion 4v.

[0025] In this embodiment, in order to solve such a problem, a reinforcing portion 4w that suppresses rotation of the upper wall 4v1 relative to the lower wall 4v2 is provided. The reinforcing portion 4w may have any configuration capable of suppressing rotation of the upper wall 4v1 relative to the lower wall 4v2.

[0026] In this embodiment, the contact protrusion 4v includes a plurality of contact protrusions 4va arranged along the circumferential direction. Intermediate regions 4vb are provided between the plurality of contact protrusions 4va. The intermediate regions 4vb are regions that protrude less from the protruding tube 4c1 than the contact protrusions 4va, or do not protrude from the protruding tube 4c1. The reinforcing portion 4w is formed by the intermediate regions 4vb. In this embodiment, the intermediate regions 4vb are regions that do not protrude from the protruding tube 4c1. The intermediate regions 4vb are less likely to deform than the contact protrusions 4va, and therefore providing the intermediate regions 4vb suppresses deformation of the contact protrusions 4va.

[0027] The contact protrusion 4v is configured by forming a plurality of contact protrusions 4va intermittently spaced apart from each other (preferably at equal intervals) in the circumferential direction. The number of the contact protrusions 4va is, for example, 2 to 16, preferably 4 or 8, and more preferably 8. When the inner preform 14 is formed by direct blow molding, it is necessary to demold the inner preform 14 from a split mold for molding. In consideration of demoldability, the number of the contact protrusions 4va is preferably 4 or 8. In addition, the more the number of the contact protrusions 4va, the higher the effect of suppressing cracking of the contact protrusions 4v, so the number of the contact protrusions 4va is more preferably 8. The contact protrusions 4va and the intermediate portion 4vb are preferably connected via an inclined surface 4vc. The inclined surface 4vc is preferably provided so as not to cause an undercut when demolding from a split mold that opens and closes in the left-right direction of FIG. 4B. The protruding inclination of the contact protrusion 4va (i.e., the inclination of the inclined surface 4vc) may be gentler than the protruding inclination of the engagement protrusion 4c2. It is preferable that the engaging protrusion 4c2 has a steep protruding inclination so as to engage with the mouth attachment member 8 in the circumferential direction, but the abutment protrusion 4va is provided to prevent the inner bag from falling off, and does not need to be engaged with another member in the circumferential direction.

[0028] The ratio of the intermediate portion 4vb to the total of the contact projection 4va and the intermediate portion 4vb is, for example, 10 to 90%, and preferably 20 to 80% (32% in the present embodiment, and 44% in the second embodiment). This value is, for example, 10, 20, 30, 40, 50, 60, 70, 80, or 90%, and may be in a range between any two of the numerical values ​​exemplified here. The total angle occupied by the intermediate portion 4vb is, for example, 60 to 300 degrees, and preferably 80 to 200 degrees (112 degrees in the present embodiment, and 140 degrees in the second embodiment). This value is, for example, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 250, or 300 degrees, and may be in a range between any two of the numerical values ​​exemplified here.

[0029] The vertical length H between the upper edge of the contact protrusion 4v and the lower edge of the engagement portion 4m is, for example, 2 mm or more, and preferably 3 mm or more (3.1 mm in this embodiment). The longer this length H is, the greater the rotational force applied to the contact protrusion 4v becomes, and the more significant the significance of applying the present invention becomes. This length is, for example, 2 to 20 mm, specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, or 20 mm, and may be in the range between any two of the numerical values ​​exemplified here, or any greater than any one of them.

[0030] The thickness of the inner bag 4 midway between the upper edge of the contact protrusion 4v and the lower edge of the engagement portion 4m is, for example, 0.5 to 1.5 mm, specifically, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5 mm, and may be in the range between any two of the numerical values ​​exemplified here.

[0031] 1-2. Manufacturing method of double container 1 The container body 2 can be manufactured by biaxially stretching and blow molding a preform 15 shown in Fig. 6. In addition, the double container 1 can be manufactured by attaching the mouth attachment member 8 to the container body 2.

[0032] <Configuration of inner preform 14, outer preform 13, and preform 15> As shown in FIG. 5, the preform 15 includes an inner preform 14 which becomes the inner bag 4 and an outer preform 13 which becomes the outer shell 3 .

[0033] As shown in FIG. 5, the inner preform 14 is a bottomed tubular member, and includes a mouth portion 14a, a body portion 14b, and a bottom portion 14c. A protrusion 14d is provided at the open end of the mouth portion 14a. The protrusion 14d is not deformed during molding and becomes the protrusion 4c in its original shape. The protrusion 14d is provided with an engagement portion 14m and a contact protrusion 14v. The engagement portion 14m and the contact protrusion 14v become the engagement portion 4m and the contact protrusion 4v, respectively, after molding. The bottom portion 14c is provided so as to close the lower end of the body portion 14b. The matters described above regarding the protrusion 4c, the engagement portion 4m, and the contact protrusion 4v can also be applied to the protrusion 14d, the engagement portion 14m, and the contact protrusion 14v, as long as they are not contrary to the spirit thereof.

[0034] As shown in Fig. 5, the outer preform 13 is a bottomed tubular member, and includes a mouth portion 13a, a body portion 13b, and a bottom portion 13c. The bottom portion 13c is provided so as to close the lower end of the body portion 13b. The bottom portion 13c is provided with an annular protrusion 13d. The mouth portion 13a is provided with a flange portion 13e.

[0035] 6, the preform 15 can be formed by covering the inner preform 14 with the outer preform 13. In the preform 15, the mouth portion 14a faces the mouth portion 13a, and the body portion 14b faces the body portion 13b.

[0036] The mouth portions 13a and 14a become the mouth portion 15a of the preform 15, the body portions 13b and 14b become the body portion 15b of the preform 15, and the bottom portions 13c and 14c become the bottom portion 15c of the preform 15. The body portion 15b and the bottom portion 15c are primarily stretched in the biaxial stretch blow molding.

[0037] <Materials and manufacturing methods of inner preform 14, outer preform 13, and preform 15> The inner preform 14 and the outer preform 13 can be formed from a thermoplastic resin such as polyester (e.g., PET) or polyolefin (e.g., polypropylene, polyethylene). The inner preform 14 can be formed by direct blow molding. The outer preform 13 can be formed by direct blow molding or injection molding.

[0038] <Manufacturing of inner preform 14 by direct blow molding> The inner preform 14 is preferably formed by direct blow molding using a tubular parison in a molten state. Since direct blow molding is easier to make the inner bag 4 thinner than injection molding, forming the inner preform 14 by direct blow molding makes it possible to make the inner bag 4 thinner. In addition, in order to form the inner bag 4 with a multi-layer structure, it is desirable for the inner preform 14 to be configured to have an inner layer, a gas barrier layer, and an outer layer in this order from the inside. In addition, it is not easy to form the inner preform 14 with such a configuration by multi-layer injection molding. For example, if a gate is provided at the bottom 14c of the inner preform 14, the resin constituting the gas barrier layer may not reach the opening end of the inner preform 14, which may result in a decrease in gas barrier properties. In particular, the smaller the thickness of the inner preform 14, the more difficult it is for the resin to flow, and the above problem becomes more pronounced. On the other hand, in direct blow molding, a tubular parison having a configuration corresponding to the inner layer, the gas barrier layer, and the outer layer is used for molding, so it is easy to provide the gas barrier layer over the entire inner preform 14.

[0039] Preferably, the gas barrier layer is made of, for example, EVOH, and the inner layer and the outer layer are made of polyolefin (e.g., polypropylene). At least one of the inner layer and the outer layer may be provided with a recycled layer. The recycled layer is made of a resin containing recycled resin, and is preferably made of a mixed resin made of recycled resin and virgin resin. By providing a recycled layer, it is possible to reduce the environmental impact and the container manufacturing costs.

[0040] 2. Second embodiment A second embodiment of the present invention will be described with reference to Figs. 7 to 9. This embodiment is similar to the first embodiment, and the description of the first embodiment can be applied to this embodiment as long as it does not go against the gist of the first embodiment. The main difference between this embodiment and the first embodiment is that the number of contact protrusions 4va provided on the contact protrusion 4v is four. Even in this form, the intermediate portion 4vb between two adjacent contact protrusions 4va functions as a reinforcing portion 4w, and cracking of the contact protrusion 4v can be suppressed. The container body 2 having such a structure can be manufactured using an inner preform 14 having a contact protrusion 14v with four contact protrusions, as shown in Fig. 9.

[0041] 3. Other embodiments In the above embodiment, the inner bag 4 is configured to be removable from the container body 2 . However, the inner bag 4 may be configured to be unremovable from the container body 2 . In the above embodiment, the mouth-mounted member 8 is attached to the mouth 5 by a plugging method, but the mouth-mounted member 8 may be attached to the mouth 5 by another method, such as a screw method. In the above embodiment, the intermediate portion 4vb is a portion that does not protrude from the protruding tube 4c1. However, even if the intermediate portion 4vb protrudes from the protruding tube 4c1, if the amount of protrusion of the intermediate portion 4vb is smaller than that of the protruding tube 4c1, the intermediate portion 4vb can suppress deformation of the abutment protrusion 4va and therefore functions as a reinforcing portion 4w. Instead of or in addition to providing the intermediate portion 4vb that functions as the reinforcing portion 4w, at least a part of the gap 4v4 may be filled with resin to suppress rotation of the upper wall 4v1 relative to the lower wall 4v2. In this case, the portion filled with resin becomes the reinforcing portion 4w. EXAMPLES

[0042] 1. Manufacturing of container body and thickness measurement <Example 1> The container body 2 (capacity 300 mL) having the shape shown in Figures 1 to 4 was obtained by biaxially stretching and blow molding the preform 15 having the shape shown in Figures 5 to 6. The thickness of the inner bag 4 at the midpoint between the upper edge of the contact protrusion 4v and the lower edge of the engagement portion 4m was about 0.8 mm. After filling the obtained container body 2 with 280 mL of water, the cap 8a shown in Figure 1 was attached to obtain a double container 1.

[0043] The inner preform 14 was produced by direct blow molding a propylene-ethylene random copolymer (type: Wintec, manufactured by Japan Polypropylene). The outer preform 13 was produced by injection molding PET (type: titanium-based catalyst grade, manufactured by Teijin) at 300°C to give the shape of the outer preform, and then quenching it to 20°C. The molten PET was made into an amorphous state by quenching. The biaxial stretch blow molding was carried out by heating the preform 15 to 110°C (the temperature at the center of the longitudinal direction of the preform 15).

[0044] <Example 2> Instead of the inner preform 14 shown in FIG. 5, the inner preform 14 shown in FIG. 9 was used to manufacture the double container 1 in the same manner as in the first embodiment.

[0045] <Comparative Example 1> Instead of the inner preform 14 shown in Figure 5, an inner preform 14 in which the abutment protrusion 14v is provided at a constant height around the entire circumference (i.e., there is no intermediate portion 4vb which becomes the reinforcing portion 4w) was used, and a double container 1 was manufactured in a manner similar to that of the first embodiment.

[0046] 2. Low temperature drop test After leaving the samples of double container 1 of the examples and comparative examples at rest for 10 hours at 5℃, they were dropped upright onto linoleum from a height of 1.2 m. The samples were dropped five times with the bottom facing down (vertical drop) and five times with the sample horizontally placed (horizontal drop), and were evaluated according to the following criteria.

[0047] The above test was carried out on 20 samples, and the number of samples in which cracks occurred in the inner bag 4 was as follows: Example 1:0 Example 2:1 Comparative Example 1:2

[0048] From the above results, it was found that the occurrence of cracks in the inner bag 4 can be suppressed by providing the reinforcing portion 4w. [Explanation of symbols]

[0049] 1:Double container 2: Container body 3: Outer shell 3a: Open end 3l: Cam rail 4: Inner bag 4c:Protrusion 4c1:Protruding tube 4c2: Engagement convex part 4c5: Circular convex part 4c8: Tapered surface 4d: Inner bag body 4g: Cam protrusion 4m: Engagement part 4v: Contact convex part 4v1 :Top wall 4v2: lower wall 4v3: Tip 4v4: Gap 4va: Contact protrusion 4vb: middle part 4vc: Inclined surface 4w: Reinforcement 5: Mouth 5b: Flange 5c: Open end 6: Torso 6b:Shoulder 6c: Main body 7: Bottom 8: Mouth attachment member 8a: Cap 13: Outer preform 13a: Mouth 13b: Torso 13c: Bottom 13d: Annular protrusion 13e: Flange part 14: Inner preform 14a: Mouth 14b: Torso 14c: Bottom 14d:Protrusion 14m: Engagement part 14v: Contact convex part 15: Preform 15a: Mouth 15b: Torso 15c: bottom 31: Cam mechanism

Claims

1. A double container comprising a container body, The container body includes an inner bag and an outer shell arranged to cover the inner bag. The inner bag has a protrusion protruding from an open end of the outer shell, The protruding portion is provided with a protruding tube and a contact protrusion, the contact protrusion is disposed at a position where it contacts the opening end and protrudes radially outward from the protruding tube, The contact protrusion has an upper wall and a lower wall extending radially outward from the protruding portion, the upper wall is disposed closer to an open end of the inner bag than the lower wall; A double container having a reinforcing portion that suppresses rotation of the upper wall relative to the lower wall.

2. The double container according to claim 1, The contact protrusion includes a plurality of contact projections arranged along a circumferential direction, An intermediate portion is provided between the plurality of contact protrusions, The intermediate portion is a portion that protrudes from the protruding tube by a smaller amount than the contact protrusion, or does not protrude from the protruding tube, The reinforcing portion is constituted by the intermediate portion.

3. The double container according to claim 2, A double container, wherein the number of the abutment protrusions is 4 or 8.

4. The double container according to any one of claims 1 to 3, The double container has an engagement portion for attaching a spout attachment member at a position closer to the open end of the inner bag than the contact protrusion.

5. The double container according to any one of claims 1 to 3, The container body is a molded body produced by biaxially stretching blow molding a preform constituted by covering an outer preform on an inner preform formed by direct blow molding, the double container being a molded body.

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