Double container

Abstract

To provide a double container capable of preventing an inner bag from floating up from a container body due to an unexpected rotation of the inner bag.SOLUTION: The present invention relates to a double container with a container body, the container body includes an inner bag and an outer shell arranged to cover the inner bag, and has a projection part on one of the inner bag and the outer shell, and a recessed part on the other of the inner bag and the outer shell, the projection part and the recessed part are configured to be engageable with each other by a relative rotation of the inner bag and the outer shell in one direction, and to be disengaged with each other by the relative rotation of the inner bag and the outer shell in the other direction, the projection part and the recessed part are engaged so that the projection part interferes with a side wall of the recessed part, and if the width of the projection part width and the recessed part width of the projection part in a natural state at a portion where the projection part interferes with the side wall are W1 and W2, respectively, then W1>W2.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 it by biaxially stretching and blow molding a preform formed by covering an inner preform with an outer preform. In the configuration of Patent Document 1, a mouth attachment member attached to the mouth of the container body includes a main body and a band, and by removing the band engaged with the outer shell, the main body engaged with the inner bag can be rotated together with the inner bag to pull out the inner bag. [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] However, in the configuration of Patent Document 1, it is necessary to remove the band part of the mouth attachment member before pulling out the inner bag, and it is desired to make it possible to pull out the inner bag with an easier operation. Therefore, a configuration can be considered in which a mouth attachment member that does not have a portion that engages with the outer shell and that engages with the inner bag in the circumferential and axial directions is adopted, and the inner bag is pulled out by rotating this mouth attachment member.

[0005] However, in the case of such a configuration, if the mouth attachment member is rotated accidentally, the inner bag will rotate together with the mouth attachment member, which may result in the inner bag floating up from the container body.

[0006] The present invention has been made in consideration of the above circumstances, and provides a double container that can prevent the inner bag from floating up from the container body due to unexpected rotation of the inner bag. [Means for solving the problem]

[0007] 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, a convex rib on one side of the inner bag and the outer shell and a concave rib on the other side of the inner bag and the outer shell, the convex rib and the concave rib are configured to be engageable with each other by relative rotation of the inner bag and the outer shell in one direction and to be disengageable by relative rotation of the inner bag and the outer shell in the other direction, the convex rib and the concave rib are engaged with each other such that the convex rib interferes with a side wall of the concave rib, and where W1 and W2 are the widths of the convex rib and the concave rib in their natural state at the portion where the convex rib and the side wall interfere with each other, W1>W2. [2] The double container according to [1], wherein the convex ribs are provided on the outer peripheral surface of the inner bag, and the concave ribs are provided on the inner peripheral surface of the outer shell. [3] A double container as described in [2], wherein a cam rail is provided on the outer peripheral surface of the outer shell, and the lower surface of the convex rib and the lower surface of the cam rail are inclined so as to approach the opening end as they proceed counterclockwise when viewed from the opening end side of the container body, and when the inner bag is rotated counterclockwise, the action of the cam mechanism formed by the convex rib and the cam rail causes the inner bag to move in the direction of coming out of the container body. [4] The double container according to any one of [1] to [3], wherein the value of (W1-W2) is 0.05 to 0.5 mm. [5] The double container according to any one of [1] to [4], wherein the convex strip is tapered toward its longitudinal end. Effect of the Invention

[0008] In the configuration of the present invention, the ridges and grooves are engaged so that the ridges interfere with the side walls of the grooves. This configuration increases the frictional force acting between the ridges and the side walls of the grooves, and increases the torque required to disengage the ridges and grooves, thereby preventing the inner bag from accidentally rotating. [Brief description of the drawings]

[0009] [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 indicate the boundary line where the curvature of the faces constituting 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] FIG. 2 is a perspective view of the vicinity of an open end of the outer shell 3. [Diagram 5] 5A is a front view of the vicinity of the mouth 5 of the container body 2 in FIG. 2, FIG. 5B is a cross-sectional view taken along line BB in FIG. 5A, FIG. 5C is an enlarged view of region C in FIG. 5B, and FIG. 5D is an exploded view of FIG. 5C. [Figure 6] FIG. 5B is an exploded view of FIG. 5A. [Figure 7] FIG. 2 is a vertical cross-sectional view of the double container 1 of FIG. [Figure 8] FIG. 2 is a perspective view showing a state in which the inner preform 14 and the outer preform 13 are separated. [Figure 9] 1 is a perspective view of a preform 15 formed by covering an inner preform 14 with an outer preform 13. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] <Detailed structure of outer shell 3 and inner bag 4> 2 to 5, 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.

[0016] 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.

[0017] 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 28c (shown in FIG. 7) provided on the mouth mounting member 8 to climb over the annular protrusion 4c5 and the engaging protrusions 4c2.

[0018] The contact protrusion 4v is disposed at a position where it abuts against the opening end 3a and is a portion that protrudes radially outward from the protruding tube 4c1. The contact protrusion 4v abuts against the opening end 3a, thereby preventing the inner bag 4 from falling off into the outer shell 3. The contact protrusion 4v preferably includes a plurality of contact protrusions 4va disposed along the circumferential direction. Intermediate portions 4vb are provided between the plurality of contact protrusions 4va. The intermediate portions 4vb are portions that protrude less from the protruding tube 4c1 than the contact protrusions 4va or do not protrude at all from the protruding tube 4c1. The intermediate portions 4vb are less likely to deform than the contact protrusions 4va, and thus providing the intermediate portions 4vb suppresses deformation of the contact protrusions 4va.

[0019] The container body 2 is preferably a molded body produced by biaxially stretching and blow molding a preform 15 (shown in Figs. 8 and 9) formed by covering an outer preform 13 with an inner preform 14 formed by direct blow molding. When the inner preform 14 is formed by direct blow molding, the strength of the contact convex portion 4v is likely to be insufficient, and the contact convex portion 4v is likely to crack when the double container 1 is dropped. However, by providing an intermediate portion 4vb in the contact convex portion 4v, deformation of the contact protrusion 4va is suppressed, and cracking of the contact convex portion 4v is suppressed.

[0020] 3, a ridge 4g is provided on the outer circumferential surface of the inner bag 4 (more specifically, the inner bag main body 4d). The lower surface of the ridge 4g is inclined counterclockwise when viewed from the opening end 5c of the mouth portion 5 so as to approach the opening end 5c.

[0021] As shown in Figs. 3 and 4, the inner peripheral surface of the outer shell 3 is provided with a cam rail 3l and a groove 3m. The groove 3m is provided so that the lower surface of the groove 3m is continuous with the upper surface of the cam rail 3l. The upper surface of the cam rail 3l and the lower surface of the groove 3m are inclined so as to approach the opening end 3a as they proceed counterclockwise when viewed from the opening end 3a side. The protrusion 4g and the groove 3m are configured to be engageable by relative rotation of the inner bag 4 and the outer shell 3 in one direction, and to be disengaged by relative rotation of the inner bag 4 and the outer shell 3 in the other direction. In this embodiment, when viewed from the opening end 3a side, the protrusion 4g can be inserted into the groove 3m to be engaged, and the protrusion 4g can be disengaged from the groove 3m by rotating the inner bag 4 clockwise with respect to the outer shell 3, and the engagement can be released by rotating the inner bag 4 counterclockwise with respect to the outer shell 3.

[0022] The width of the convex rib 4g is slightly larger than the width of the concave rib 3m. Therefore, the convex rib 4g and the concave rib 3m engage with each other so that the convex rib 4g interferes with the side wall 3m1 of the concave rib 3m. More specifically, as shown in Figs. 5C to 5D, if the widths of the convex rib 4g and the concave rib 3m in the natural state (when no external force is applied) of the portion 33 where the convex rib 4g and the side wall 3m1 interfere are W1 and W2, respectively, W1>W2. W1 and W2 are lengths in the direction in which the central axis C of the mouth portion 5 extends.

[0023] In this case, when the inner bag 4 is rotated with respect to the outer shell 3 to insert the convex strip 4g into the concave strip 3m, the convex strip 4g is pushed into the concave strip 3m so that the convex strip 4g and the side wall 3m1 push each other aside. In FIG. 5C, for convenience of illustration, the convex strip 4g and the concave strip 3m are illustrated without deformation, but in reality, when the convex strip 4g is pushed into the concave strip 3m, one or both of the convex strip 4g and the concave strip 3m are deformed from their natural state, and the convex strip 4g and the side wall 3m1 are pressed against each other by the restoring force, increasing the frictional force. As shown in FIG. 5D, when the convex strip 4g is hollow, the convex strip 4g is more easily deformed than the concave strip 3m, so that when the convex strip 4g is pushed into the concave strip 3m, the convex strip 4g is more likely to be deformed preferentially. To release the engagement between the convex strip 4g and the concave strip 3m from this state, it is necessary to apply a torque exceeding the frictional force acting between the convex strip 4g and the side wall 3m1. This prevents the inner bag 4 from being accidentally rotated before the contents are used up. The magnitude of the torque required to rotate the inner bag 4 can be adjusted by changing the degree of interference between the ridge 4g and the side wall 3m1.

[0024] Instead of having the ridges 4g and the side wall 3m1 interfere with each other, it is possible to prevent the inner bag 4 from rotating unexpectedly by, for example, engaging a ridge on the inner bag 4 with an engaging portion on the outer shell 3, but in this case, if force is applied to the ridge, the ridge may break and pinholes may be formed in the inner bag 4. In contrast, in this embodiment, the width of the ridges 4g is made slightly larger than the width of the recessed ridges 3m to increase the friction between them and prevent the inner bag 4 from rotating unexpectedly, thereby preventing the occurrence of pinholes caused by breakage of the ridges.

[0025] The value of (W1-W2) is, for example, 0.05 to 0.5 mm (0.2 mm in this embodiment), specifically, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50 mm, and may be in the range between any two of the values ​​exemplified here. Here, the value of (W1-W2) is the value at the portion where the interference between the protrusion 4g and the side wall 3m1 is strongest.

[0026] In other words, the value of {(W1-W2) / W2} is, for example, 3 to 33% (approximately 13% in this embodiment), and this value may be specifically, for example, 3, 5, 10, 15, 20, 25, 30, or 33%, or may be in a range between any two of the numerical values ​​exemplified here.

[0027] It is preferable that the ridge 4g is tapered (the width becomes smaller) toward the tip 4g1 in the longitudinal direction of the ridge 4g. It is more preferable that the width of the ridge 4g at the tip 4g1 is the same as or smaller than the width of the groove 3m. In this case, there is an advantage that the ridge 4g can be easily inserted into the groove 3m.

[0028] W1 is, for example, 1.0 to 3.0 mm (in this embodiment, 1.5 mm at the portion near the tip 4g1 and 1.7 mm at the portion where interference with the side wall 3m1 is strongest), and more specifically, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.5, 3.0 mm, and may be in a range between any two of the numerical values ​​exemplified here.

[0029] The ridge 4g is preferably tapered in the direction protruding from the inner bag body 4d (leftward in FIG. 5D). In other words, the width of the ridge 4g is preferably increased toward the base of the ridge 4g in the protruding direction (that is, toward the inner bag body 4d). In addition, the base of the ridge 4g is provided with a curved portion 4g3 that is convex inward, which is expected to have technical effects such as suppressing cracking in the ridge 4g and improving the releasability of the ridge 4g. The width of the ridge 4g is wider at the curved portion 4g3, and the curved portion 4g3 interferes with the side wall 3m1. The protruding height of the ridge 4g is, for example, 0.5 to 1.5 mm (1.0 mm in this embodiment), 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.

[0030] The length L1 of the protrusion 4g in the longitudinal direction is, for example, 5 to 40 mm (about 22 mm in this embodiment), specifically, for example, 5, 10, 15, 20, 25, 30, 35, or 40 mm, or may be in the range between any two of the numerical values ​​exemplified here.L1 / W1 is, for example, 5 to 30 (about 13 in this embodiment), specifically, for example, 5, 10, 15, 20, 25, or 30, or may be in the range between any two of the numerical values ​​exemplified here.

[0031] The length L2 of the groove 3m in the longitudinal direction is, for example, 3 to 30 mm (8.5 mm in this embodiment), preferably 3 to 15 m, specifically, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 mm, or may be in the range between any two of the numerical values ​​exemplified here.L2 / W2 is, for example, 3 to 20, specifically, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, or may be in the range between any two of the numerical values ​​exemplified here. If the length of the inner circumference of the outer shell 3 at the portion where the recess 3m is provided is L3, then L2 / L3 is preferably, for example, 0.05 to 0.30, and specifically, for example, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.20, 0.25, 0.30, and may be in a range between any two of the numerical values ​​exemplified here.

[0032] Before the inner bag 4 is pulled out from the container body 2, the lower surface of the convex strip 4g abuts against the upper surface of the cam rail 3l. The convex strip 4g and the cam rail 3l form the cam mechanism 31. In this embodiment, the concave strip 3m is a through hole, but it may be a blind hole.

[0033] When an attempt is made to rotate the inner bag 4 counterclockwise, the rotation is restricted by the frictional force between the ridges 4g and the side wall 3m1. This restriction is not strong, and when a strong torque (torque equal to or greater than the inner plug rotation torque T2 described below) is applied to the inner bag 4, the engagement between the ridges 4g and the recesses 3m is released, allowing the inner bag 4 to rotate freely relative to the outer shell 3. When the inner bag 4 is further rotated counterclockwise, the inner bag 4 moves in a direction that allows it 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 its diameter is reduced.

[0034] <Rotation direction and torque of the overcap 27 and the inner plug 26> 7, the mouth attachment member 8 is preferably a cap 8a, and includes an inner plug 26 and an overcap 27. The inner plug 26 is engaged with the mouth 5 of the inner bag 4 in the circumferential and axial directions by a plugging method. The overcap 27 is screwed onto the inner plug 26. It is preferable that the mouth attachment member 8 is not engaged with the outer shell 3 in either the circumferential or axial directions.

[0035] The overcap 27 is preferably screwed onto the inner plug 26 by a clockwise thread. Therefore, by rotating the overcap 27 relative to the inner plug 26 in the clockwise loosening direction, the screw engagement between the overcap 27 and the inner plug 26 can be released. Also, by rotating the inner plug 26 relative to the outer shell 3 in the clockwise loosening direction, the inner bag 4 is configured to move in a direction in which it comes out of the container body 2. In this way, by rotating the overcap 27 in the clockwise loosening direction, the overcap 27 can be removed, and by rotating the inner plug 26 in the clockwise loosening direction, the inner bag 4 can be lifted up. Both operations are performed in the same rotation direction, and therefore have the advantage of being simple.

[0036] On the other hand, in the case of the above configuration, when the container body 2 and the overcap 27 are grasped and the overcap 27 is rotated in the clockwise loosening direction, the overcap 27 does not rotate relative to the inner stopper 26, but the overcap 27 and the inner stopper 26 rotate together relative to the container body 2, which may result in the inner bag 4 floating up.

[0037] In order to prevent the occurrence of such problems, if the overcap rotation torque required to initially rotate the overcap 27 relative to the inner plug 26 in the clockwise loosening direction is T1, and the inner plug rotation torque required to initially rotate the inner plug 26 relative to the outer shell 3 in the clockwise loosening direction is T2, then it is preferable that T2 / T1 is 1.2 or more. By applying a torque equal to or greater than the overcap rotation torque T1 to the overcap 27, the overcap 27 can be rotated in the loosening direction. By applying a torque equal to or greater than the inner plug rotation torque T2 to the inner plug 26, the inner plug 26 can be rotated in the loosening direction.

[0038] In this case, when the container body 2 and the overcap 27 are gripped and the overcap 27 is rotated in the clockwise loosening direction, the overcap 27 rotates relative to the inner plug 26 before the inner plug 26 rotates relative to the outer shell 3, thereby preventing the occurrence of the above problem. T2 / T1 is, for example, 1.2 to 5, and preferably 1.5 to 3. Specifically, T2 / T1 is, for example, 1.2, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0, and may be within a range between any two of the numerical values ​​exemplified here.

[0039] T1 is, for example, 30 to 150 N·cm, and preferably 50 to 120 N·cm. T2 is, for example, 100 to 200 N·cm, and preferably 130 to 170 N·cm. T1 is specifically, for example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 150 N·cm, and may be within a range between any two of the numerical values ​​exemplified here. T2 is specifically, for example, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 N·cm, and may be within a range between any two of the numerical values ​​exemplified here.

[0040] In this embodiment, as shown in FIG. 7, the inside plug 26 includes a main body 28 and an opening part 32. The main body 28 and the opening part 32 are connected to each other via an easily tearable connecting part 30. The opening part 32 is provided with an engagement tube 32a provided with an engagement part (not shown), and the engagement tube 27a provided on the overcap 27 and the engagement tube 32a are engaged in the circumferential direction and the axial direction. With this configuration, it is possible to rotate the engagement tube 32a relative to the main body 28 by rotating the overcap 27 relative to the main body 28, thereby breaking the connecting part 30. By breaking the connecting part 30, the opening part 32 is separated from the main body 28, and a flow hole is formed in the inside plug 26. The contents in the inner bag 4 can be discharged through this flow hole.

[0041] In this embodiment, the overcap rotation torque T1 is a torque required to break the connecting portion 30 and separate the opening portion 32 from the main body portion 28. In another embodiment, instead of providing the opening portion 32 on the inside plug 26, an opening ring is provided on the overcap 27 via an easily tearable connecting portion, and the opening ring engages with the inside plug 26 in the circumferential direction. In such a configuration, the torque required to break the thin-walled portion and separate the opening ring from the overcap 27 is the overcap rotation torque T1. In yet another embodiment, a rotation restriction structure is provided to restrict the rotation of the overcap 27 relative to the inside plug 26, and when the restriction on rotation by the rotation restriction structure is released at a predetermined torque (for example, when the convex portion of the overcap 27 and the convex portion of the inside plug 26 come into contact with each other to restrict rotation, and the convex portion of the overcap 27 overcomes the convex portion of the inside plug 26 to release the restriction), the torque required to release the restriction is the overcap rotation torque T1.

[0042] In this embodiment, the inner plug rotation torque T2 is a torque required to release the engagement between the convex rib 4g and the concave rib 3m.

[0043] Furthermore, if the overturn torque required to initially rotate the inner plug 26 in the clockwise loosening direction relative to the inner bag 4 is T3, then T3 / T2 is preferably 1.2 or more. This prevents the inner plug 26 from spinning freely relative to the inner bag 4. T3 / T2 is, for example, 1.2 to 5, and preferably 1.5 to 3. Specifically, T3 / T2 is, for example, 1.2, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0, and may be within a range between any two of the numerical values ​​exemplified here, or equal to or greater than any one of them.

[0044] T3 is, for example, 200 N·cm or more, preferably 200 to 1000 N·cm, and specifically, for example, 200, 250, 300, 350, 400, 500, or 1000 N·cm, and may be within a range between any two of the numerical values ​​exemplified here or equal to or greater than any one of them. In this embodiment, the overturn torque T3 is the torque required for the engaging protrusion (not shown) of the inside plug 26 to overcome the engaging protrusion 4c2.

[0045] <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.

[0046] 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.

[0047] According to this configuration, by rotating the mouth attachment member 8, the inner bag 4 can be moved in a direction that causes it to come out of 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.

[0048] 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. 9. In addition, the double container 1 can be manufactured by attaching the mouth attachment member 8 to the container body 2.

[0049] <Configuration of inner preform 14, outer preform 13, and preform 15> As shown in FIG. 8, 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 .

[0050] As shown in Fig. 8, the inner preform 14 is a bottomed tubular member, and includes an opening 14a, a body 14b, and a bottom 14c. The opening 14a is provided with a protrusion 14d and a convex 14g. The protrusion 14d is provided with an engagement portion 14m and abutment convex 14v. The engagement portion 14m, the abutment convex 14v, and the convex 14g become the engagement portion 4m, the abutment convex 4v, and the convex 4g, respectively, after molding. The bottom 14c is provided to close the lower end of the body 14b.

[0051] As shown in Fig. 8, 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 convex portion 13d. The mouth portion 13a is provided with a flange portion 13e. The mouth portion 13a is provided with a concave strip 13m, which becomes the concave strip 3m after molding.

[0052] 9, a 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.

[0053] 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 mainly stretched in the biaxial stretch blow molding. The mouth portion 15a is hardly deformed during molding and becomes the mouth portion 5 of the container body 2. The above-mentioned contents regarding the configuration included in the mouth portion 5 can also be applied to the configuration included in the mouth portion 15a as long as it is not contrary to the spirit thereof.

[0054] <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.

[0055] <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.

[0056] 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.

[0057] 2. Other embodiments In the above embodiment, the convex rib 4g that constitutes the cam mechanism 31 is engaged with the concave rib 3m that is connected to the cam rail 3l that constitutes the cam mechanism 31 to suppress unexpected rotation of the inner bag 4. However, unexpected rotation of the inner bag 4 may also be suppressed by engaging a convex rib and a concave rib that are provided independently of the cam mechanism 31. In the above embodiment, the convex ridges on the inner bag 4 and the concave ridges on the outer shell 3 are engaged with each other, but the concave ridges on the inner bag 4 and the convex ridges on the outer shell 3 may also be engaged with each other to prevent the inner bag 4 from rotating unexpectedly. [Explanation of symbols]

[0058] 1:Double container 2: Container body 3: Outer shell 3a: Open end 3l: Cam rail 3m: Concave 3m1: side wall 4: Inner bag 4c:Protrusion 4c1:Protruding tube 4c2: Engagement convex part 4c5: Circular convex part 4c8: Tapered surface 4d: Inner bag body 4g: Convex stripe 4g1: Tip 4g3: Curved section 4m: Engagement part 4v: Contact convex part 4va: Contact protrusion 4vb: middle part 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 13m: Concave 14: Inner preform 14a: Mouth 14b: Torso 14c: Bottom 14d:Protrusion 14g: Convex strip 14m: Engagement part 14v: Contact convex part 15: Preform 15a: Mouth 15b: Torso 15c: bottom 26: Inner stopper 27: Overcap 27a: Engagement tube 28: Main body 28c: Circular convex part 30:Connection part 31: Cam mechanism 32: Opening section 32a: Engagement tube 33: Part C: Central axis T1: Overcap rotation torque T2: Inner plug rotation torque T3: Overturn torque

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. A convex strip is provided on one of the inner bag and the outer shell, and a concave strip is provided on the other of the inner bag and the outer shell, the protrusions and the recesses are configured to be engageable with each other by relative rotation of the inner bag and the outer shell in one direction, and to be disengaged with each other by relative rotation of the inner bag and the outer shell in the other direction, The protrusion and the recess are engaged such that the protrusion interferes with a side wall of the recess; A double container, in which, when the width of the convex rib and the width of the concave rib in a natural state at a portion where the convex rib and the side wall interfere with each other are W1 and W2, respectively, W1 > W2.

2. The double container according to claim 1, The protrusion is provided on an outer circumferential surface of the inner bag, The recessed ribs are provided on the inner peripheral surface of the outer shell.

3. The double container according to claim 2, A cam rail is provided on the outer peripheral surface of the outer shell, The lower surface of the convex strip and the lower surface of the cam rail are inclined so as to approach the open end as they proceed counterclockwise when viewed from the open end side of the container body, The double container is configured such that when the inner bag is rotated counterclockwise, the inner bag moves in a direction to come out of the container body due to the action of a cam mechanism formed by the protrusion and the cam rail.

4. The double container according to any one of claims 1 to 3, A double container, wherein the value of (W1-W2) is 0.05 to 0.5 mm.

5. The double container according to any one of claims 1 to 3, The convex strip is tapered toward its longitudinal end.

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